Author Topic: Using a hypersonic aircraft as a LEO launcher  (Read 66608 times)

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« on: 06/27/2014 06:56 pm »
I recently saw a picture of the SR-71 with the D-21 rocket powered drone on its back and though it's not the same it made me wonder if you could piggyback a launcher for small payloads to LEO on something like the proposed SR-72 hypersonic aircraft. Would there be any advantages to launching from a aircraft at Mach 6 flying at say something like 150,000 feet compared to a more conventional launch aircraft? Or would any advantages be offset by greater difficulties from using such a vehicle.

http://www.lockheedmartin.co.uk/us/news/features/2013/sr-72.html


Offline Alf Fass

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #1 on: 06/28/2014 04:18 am »
There have been a few proposals for supersonic and hypersonic air launch over the years (eg. Sanger II), the problem has always been the enormous cost of the aircraft. For even a modest payload to LEO you need a really big (expensive) supersonic plane, so far it looks cheaper to just go with an existing plane (Orbital Science Corporation L-1011 "Stargazer" plane), or possibly a more extensive modification of existing hardware (Stratolaunch).
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Offline hop

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #2 on: 06/28/2014 04:37 am »
People have been thinking about this since the dawn of the space age. See Spiral for example.... but large hypersonic aircraft are really expensive to develop. It's not at all clear this is a win over a conventional booster.

I'm not clear what the payload capacity of the SR-72 is supposed to be, but if it's comparable to the SR-71 it would only be good for a tiny tiny. The D21 was something like 5 tons (also it was ramjet powered, not rocket). For comparison, the original Pegasus (not XL) was more like 18 tons.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #3 on: 06/28/2014 08:32 am »
This notion keeps coming up. In effect it was also the plan for the original STS concept.

A good rule of thumb for any launch assist technology is "Does it reduce the number of stages of the LV."

Pegasus didn't. It's 3 stage + aircraft (or 5 if you go with the liquid upper stage)

The payoff in that case was the much simplified range rules.

Normal TSTO ELV's stage about M10, so you're looking at a big very high velocity aircraft to do this.

That's a lot of pain for not much gain.  :(
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Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #4 on: 06/28/2014 10:20 am »

People have been thinking about this since the dawn of the space age. See Spiral for example.... but large hypersonic aircraft are really expensive to develop. It's not at all clear this is a win over a conventional booster.

I'm not clear what the payload capacity of the SR-72 is supposed to be, but if it's comparable to the SR-71 it would only be good for a tiny tiny. The D21 was something like 5 tons (also it was ramjet powered, not rocket). For comparison, the original Pegasus (not XL) was more like 18 tons.

The concept of the SR-72 from the information LM put out in AW posits an aircraft that looks slightly bigger than the SR-71. I was thinking along the lines of deploying the smaller end of satellites perhaps cubesats and a bit bigger. Would that be a workable concept, or would the launcher for such payloads still need to be too big for such a size of aircraft?

The thing is if LM have created a concept for a workable engine allowing hypersonic performance is there anything in theory stopping them putting these on a larger airframe.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #5 on: 06/28/2014 11:04 am »
The concept of the SR-72 from the information LM put out in AW posits an aircraft that looks slightly bigger than the SR-71. I was thinking along the lines of deploying the smaller end of satellites perhaps cubesats and a bit bigger. Would that be a workable concept, or would the launcher for such payloads still need to be too big for such a size of aircraft?
Well the SR71 accomdated the D21 drone at about 5 tonnes. Given the usual ELV payload is 3% of GTOW that would about 150Kg to orbit.
Provided someone has put up the shed load of cash to build the "SR72" (which is a powerpoint plane at this point) and this ELV add on.

That kind of money buys an awful lot of Pegasus launches.
Quote
The thing is if LM have created a concept for a workable engine allowing hypersonic performance is there anything in theory stopping them putting these on a larger airframe.
Let's go through the logic chain.

 if LM have a viable engine and if they get a sponsor (because you can bet they won't internally fund this) to build the aircraft and if they get a sponsor to build the LV then yes they probably could launch payloads to LEO.

Now why would they want to?

What's in it for them?

My instinct is that when the first SCEPTRE engine starts ground tests in about 3 years they will still be talking about this.

As they will in 7 years time, when the first Skylon starts flight testing.
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Offline Nomadd

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #6 on: 06/28/2014 11:19 am »
 If you compared it with Stratolauncher, you'd lose the advantages that air launch has over ground launch and 90-95% of the payload.
« Last Edit: 06/28/2014 11:20 am by Nomadd »
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Offline dror

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #7 on: 06/28/2014 12:49 pm »
The point as I see it is not about developing an airplane and building or buying it.
The point is using an existing one for the differnt purpose of aiding an LV.
There's a wide range of existing airplanes + LV that could be considered.
One example is Pegasus, so the principal is proven.
The coming one will be Stratolaunch so we know the principle can be extended.
What will the next one be?

Take Rockwell B1 Lancer - an active supersonic heavy bomber:

"Payload: 125,000 lb (56,700 kg) ; internal and external ordnance combined
Maximum speed: At altitude: Mach 1.25
Service ceiling: 60,000 ft (18,000 m)
"(Wiki http://en.m.wikipedia.org/wiki/Rockwell_B-1B_Lancer )

Seems like it can take a substantial mass to a sustantial hight and speed.
What kind of LV can it carry?
What size of a of payload?
How much is the cost of one flight compared to the cost of the launch pad and first stage?
Is it viable?

The next level is hypersonic, but we are not there yet.
« Last Edit: 06/28/2014 12:53 pm by dror »
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Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #8 on: 06/28/2014 03:47 pm »
Take Rockwell B1 Lancer - an active supersonic heavy bomber:
Wrong.

The B1a was supersonic. The B1B has fixed inlets and is subsonic.  :(

It's certainly not hypersonic.
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Offline bubbagret

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #9 on: 06/28/2014 04:53 pm »
Take Rockwell B1 Lancer - an active supersonic heavy bomber:
Wrong.

The B1a was supersonic. The B1B has fixed inlets and is subsonic.  :(

It's certainly not hypersonic.
The B1-B is supersonic at altitude with fixed inlets, M1.25. The B1-A was M2.2+ capable with variable inlets.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #10 on: 06/28/2014 07:34 pm »
The concept of the SR-72 from the information LM put out in AW posits an aircraft that looks slightly bigger than the SR-71. I was thinking along the lines of deploying the smaller end of satellites perhaps cubesats and a bit bigger. Would that be a workable concept, or would the launcher for such payloads still need to be too big for such a size of aircraft?
Well the SR71 accomdated the D21 drone at about 5 tonnes. Given the usual ELV payload is 3% of GTOW that would about 150Kg to orbit.
Provided someone has put up the shed load of cash to build the "SR72" (which is a powerpoint plane at this point) and this ELV add on.

That kind of money buys an awful lot of Pegasus launches.
Quote
The thing is if LM have created a concept for a workable engine allowing hypersonic performance is there anything in theory stopping them putting these on a larger airframe.
Let's go through the logic chain.

 if LM have a viable engine and if they get a sponsor (because you can bet they won't internally fund this) to build the aircraft and if they get a sponsor to build the LV then yes they probably could launch payloads to LEO.

Now why would they want to?

What's in it for them?

My instinct is that when the first SCEPTRE engine starts ground tests in about 3 years they will still be talking about this.

As they will in 7 years time, when the first Skylon starts flight testing.

At the time of the AW piece appearing some online suggested that LM released this concept because of REL, I personally don't quite see the logic of this as they are hardly comparable being as REL have actual hardware in existence and LM is a design concept. But that's the internet for you the home of unfounded speculation.:)
« Last Edit: 06/28/2014 08:00 pm by Star One »

Offline lkm

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #11 on: 06/28/2014 08:53 pm »
I was wondering a while ago about the possibility of half scale SABRE engines for a test vehicle and it occurred to me  that if you could could replace the B1 lancer's fuel tanks with cryogenic tankage and the jet engine pods with SABRE nacelles the B1 airframe is designed to handle mach 2+ and could possibly rock zoom from there  to mach 8 for an air launch. It would make an interesting test aircraft both for engine development and for the logistics of cryogenically fueled aircraft management and handling. The B1 has about 215m3 of fuel volume, or about 16mt of Hydrogen IIRC.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #12 on: 06/28/2014 10:02 pm »
I was wondering a while ago about the possibility of half scale SABRE engines for a test vehicle and it occurred to me  that if you could could replace the B1 lancer's fuel tanks with cryogenic tankage and the jet engine pods with SABRE nacelles the B1 airframe is designed to handle mach 2+ and could possibly rock zoom from there  to mach 8 for an air launch. It would make an interesting test aircraft both for engine development and for the logistics of cryogenically fueled aircraft management and handling. The B1 has about 215m3 of fuel volume, or about 16mt of Hydrogen IIRC.
A single B1 engine in full burner is 30 000lbf of thrust. A SABRE is 360 000 lbf of thrust.

Firstly there no B1B has been released for test purposes. Secondly there is no real point in building a 1/12 scale SABRE to fit to such a vehicle. Thirdly a full air breathing cycle for a SABRE is to M5.5. A B1B will not 
survive sustained flight at that

The best flight test vehicle for SABRE remains a Skylon.
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Offline IslandPlaya

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #13 on: 06/28/2014 10:14 pm »
In operation, how long would Skylon spend between Mach 3 and 5.5 when it enters rocket mode?

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #14 on: 06/28/2014 10:17 pm »

I was wondering a while ago about the possibility of half scale SABRE engines for a test vehicle and it occurred to me  that if you could could replace the B1 lancer's fuel tanks with cryogenic tankage and the jet engine pods with SABRE nacelles the B1 airframe is designed to handle mach 2+ and could possibly rock zoom from there  to mach 8 for an air launch. It would make an interesting test aircraft both for engine development and for the logistics of cryogenically fueled aircraft management and handling. The B1 has about 215m3 of fuel volume, or about 16mt of Hydrogen IIRC.
A single B1 engine in full burner is 30 000lbf of thrust. A SABRE is 360 000 lbf of thrust.

Firstly there no B1B has been released for test purposes. Secondly there is no real point in building a 1/12 scale SABRE to fit to such a vehicle. Thirdly a full air breathing cycle for a SABRE is to M5.5. A B1B will not 
survive sustained flight at that

The best flight test vehicle for SABRE remains a Skylon.

Yes well that depends on them finding someone willing to give them the not inconsiderable amount of money to build Skylon, something I am far from convinced is going to happen anytime soon.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #15 on: 06/28/2014 11:25 pm »

Yes well that depends on them finding someone willing to give them the not inconsiderable amount of money to build Skylon, something I am far from convinced is going to happen anytime soon.
No. It requires REL finding someone to lend them the money (at market rates) to build it. Given they have a) Met all development schedules to date when fully funded and b) Had extensive outside verification that their technology is sound the chances are surprisingly good.

Somewhat more likely than REL building a pair of 1/12th scale SABRE engines and getting them fitted to an B1B.

However this remains off topic as the B1B was not designed to be anywhere near hypersonic IE > M5.

In fact AFAIK the nearest thing to what you're looking for is DARPA's XS1 project, which is designed to hit M10.
« Last Edit: 06/28/2014 11:39 pm by john smith 19 »
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Offline lkm

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #16 on: 06/28/2014 11:31 pm »
I was wondering a while ago about the possibility of half scale SABRE engines for a test vehicle and it occurred to me  that if you could could replace the B1 lancer's fuel tanks with cryogenic tankage and the jet engine pods with SABRE nacelles the B1 airframe is designed to handle mach 2+ and could possibly rock zoom from there  to mach 8 for an air launch. It would make an interesting test aircraft both for engine development and for the logistics of cryogenically fueled aircraft management and handling. The B1 has about 215m3 of fuel volume, or about 16mt of Hydrogen IIRC.
A single B1 engine in full burner is 30 000lbf of thrust. A SABRE is 360 000 lbf of thrust.

Firstly there no B1B has been released for test purposes. Secondly there is no real point in building a 1/12 scale SABRE to fit to such a vehicle. Thirdly a full air breathing cycle for a SABRE is to M5.5. A B1B will not 
survive sustained flight at that

The best flight test vehicle for SABRE remains a Skylon.
Yes it would be tremedously over powered and this was really just a thought experiment regarding whether there were any suitable existing airframes you could stick a SABRE on but I was really rather thinking of it as something the USAF might do down the road to to explore the performance and needs of the engine type before committing to a cruise engine development program for some future bomber and not something REL would be doing.   Also I wasn't suggesting airbreathing to M5.5, rather that you could go to the rocket mode before you hit the limit of the airframe somewhere around Mach 3.

Offline hop

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #17 on: 06/28/2014 11:49 pm »
The concept of the SR-72 from the information LM put out in AW posits an aircraft that looks slightly bigger than the SR-71.
The airframe being slightly bigger does not mean the payload capacity is bigger. One would expect a hypersonic vehicle to have a worse payload fraction.

There's also the issue of deploying the launcher. The D-21 was originally planned to be launched from the SR-71, but they ended up switching to a conventional solid rocket booster launched from a B-52 instead because launching it from the SR-71 was too hairy. Some of this has to do with the specifics of the SR-71 setup, but unless you can get out of the atmosphere for the actual deployment it will generally get harder at higher speeds.

Just carrying the launcher is also likely to be challenging. Hypersonic aerodynamics are very sensitive, so a large external payload is likely to have a major performance impact if it is possible at all. An internal payload bay may be possible, but will put constraints on the launcher dimensions and add a lot of cost if it isn't part of the normal SR-72 design.
Quote
I was thinking along the lines of deploying the smaller end of satellites perhaps cubesats and a bit bigger. Would that be a workable concept, or would the launcher for such payloads still need to be too big for such a size of aircraft?
I've read PSLV-CA launches go for something like $17 million, and can put ~1 ton into to LEO. That's a lot of cubesats, any very tiny fraction of what something like the SR-72 program would cost. Even if you assume the basic SR-72 program is paid for by someone else, just the cost of developing the launch system would buy you a pretty substantial number of conventional smallsat launches.

Offline IslandPlaya

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #18 on: 06/28/2014 11:50 pm »
I was wondering a while ago about the possibility of half scale SABRE engines for a test vehicle and it occurred to me  that if you could could replace the B1 lancer's fuel tanks with cryogenic tankage and the jet engine pods with SABRE nacelles the B1 airframe is designed to handle mach 2+ and could possibly rock zoom from there  to mach 8 for an air launch. It would make an interesting test aircraft both for engine development and for the logistics of cryogenically fueled aircraft management and handling. The B1 has about 215m3 of fuel volume, or about 16mt of Hydrogen IIRC.
A single B1 engine in full burner is 30 000lbf of thrust. A SABRE is 360 000 lbf of thrust.

Firstly there no B1B has been released for test purposes. Secondly there is no real point in building a 1/12 scale SABRE to fit to such a vehicle. Thirdly a full air breathing cycle for a SABRE is to M5.5. A B1B will not 
survive sustained flight at that

The best flight test vehicle for SABRE remains a Skylon.
Yes it would be tremedously over powered and this was really just a thought experiment regarding whether there were any suitable existing airframes you could stick a SABRE on but I was really rather thinking of it as something the USAF might do down the road to to explore the performance and needs of the engine type before committing to a cruise engine development program for some future bomber and not something REL would be doing.   Also I wasn't suggesting airbreathing to M5.5, rather that you could go to the rocket mode before you hit the limit of the airframe somewhere around Mach 3.
I think this is a valid idea for the USAF supported by REL. I'm guessing but if the airframe could support close to M3 in sustained flight then maybe it could do a sprint to >M4 for a limited period. Hence my question above. All done unmanned of course.
« Last Edit: 06/28/2014 11:51 pm by IslandPlaya »

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #19 on: 06/29/2014 08:11 am »
I've read PSLV-CA launches go for something like $17 million, and can put ~1 ton into to LEO. That's a lot of cubesats, any very tiny fraction of what something like the SR-72 program would cost. Even if you assume the basic SR-72 program is paid for by someone else, just the cost of developing the launch system would buy you a pretty substantial number of conventional smallsat launches.
That's dirt cheap but of course but with the US government paranoia about overseas launches you'd probably only have the Pegasus XL available.

While this is reckoned to be the most expensive LV per lb/$ to orbit I'd guess any realistic development programme budget would be the equivalent of several Pegasus launches a year for a decade.
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Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #20 on: 06/29/2014 08:21 am »
In operation, how long would Skylon spend between Mach 3 and 5.5 when it enters rocket mode?

The Skylon C1 trajectory data can be found here

http://www.reactionengines.co.uk/tech_docs.html

It's roughly 6 minutes.



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Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #21 on: 06/29/2014 08:31 am »
I think this is a valid idea for the USAF supported by REL. I'm guessing but if the airframe could support close to M3 in sustained flight then maybe it could do a sprint to >M4 for a limited period. Hence my question above. All done unmanned of course.
I'm really struggling to understand how shoe horning one or more SABRE's onto a B1B airframe will have any relevance to the idea of a hypersonic launch assist stage. :( That's the title of this thread.

IRL the USAF would need REL to design a sub scale SABRE for them, they can't do it themselves and neither can their regular contractors (because they don't know how).

Hempsell on the Skylon threads stated LH2/LO2 engines scale down badly. He estimated they would spend Ł250m on a scaled down LH2 pump for the SCEPTRE ground test engine. At that point they decided to go for a little bit more funding and go with a full size ground test, instead of a sub scale.

OTOH REL have studied an M5 aircraft and an engine to power it under LAPCAT.

It's a very different beast because it's a very different mission.
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Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #22 on: 06/29/2014 09:13 am »
I hope this isn't too OT but is correct that back in the nineties REL were offered US money for development?

Offline lkm

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #23 on: 06/29/2014 10:56 am »
I think this is a valid idea for the USAF supported by REL. I'm guessing but if the airframe could support close to M3 in sustained flight then maybe it could do a sprint to >M4 for a limited period. Hence my question above. All done unmanned of course.
I'm really struggling to understand how shoe horning one or more SABRE's onto a B1B airframe will have any relevance to the idea of a hypersonic launch assist stage. :( That's the title of this thread.

IRL the USAF would need REL to design a sub scale SABRE for them, they can't do it themselves and neither can their regular contractors (because they don't know how).

Hempsell on the Skylon threads stated LH2/LO2 engines scale down badly. He estimated they would spend Ł250m on a scaled down LH2 pump for the SCEPTRE ground test engine. At that point they decided to go for a little bit more funding and go with a full size ground test, instead of a sub scale.

OTOH REL have studied an M5 aircraft and an engine to power it under LAPCAT.

It's a very different beast because it's a very different mission.

Well, as I think you'll agree, there are no existing hypersonic aircraft, certainly no large ones capable of air launch. Also the cost of designing and building a new purpose built aircraft would be at least as much, if not more, than the cost of building Skylon. It's for this reason that most schemes for supersonic airlaunch involve sticking some rockets on an existing subsonic aircraft for a rocket zoom out of the atmosphere, bodging is cheaper.
So if you want to do hypersonic air launch, as per the thread, a bodged B1 would be cheaper than a new aircraft. Should the USAF wish to do such a crazy thing, of course REL would be contracted for the engine, and paid handsomely for it, no doubt it would have to be the notional US subsidiary supplying the notional US Skylon airframer being contracted. 

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #24 on: 06/29/2014 11:35 am »
Well, as I think you'll agree, there are no existing hypersonic aircraft, certainly no large ones capable of air launch. Also the cost of designing and building a new purpose built aircraft would be at least as much, if not more, than the cost of building Skylon. It's for this reason that most schemes for supersonic airlaunch involve sticking some rockets on an existing subsonic aircraft for a rocket zoom out of the atmosphere, bodging is cheaper.
So if you want to do hypersonic air launch, as per the thread, a bodged B1 would be cheaper than a new aircraft. Should the USAF wish to do such a crazy thing, of course REL would be contracted for the engine, and paid handsomely for it, no doubt it would have to be the notional US subsidiary supplying the notional US Skylon airframer being contracted.
AFAIK the only one currently being talked about is the XS1 project from DARPA.

That is looking to go to M10 with a 3000lb payload. If you can pack an ELV in 3000lb then that would pretty much fit the bill.

The X15 did get to M6.15 in the mid 60's.

The B1B is not  rated beyond about M2.25 (which is what the a version got to). If you're air breathing anyway you'd go with the LAPCAT engine instead and only have to worry about LH2 storage, not both LH2 and LO2.

The idea of airborne launch assist (both sub and supersonic) has been discussed at length on this site and on various news groups (primarily sci.space.tech) for the last 25 years.

You might like to read some of that before commenting further.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #25 on: 06/29/2014 02:06 pm »

Well, as I think you'll agree, there are no existing hypersonic aircraft, certainly no large ones capable of air launch. Also the cost of designing and building a new purpose built aircraft would be at least as much, if not more, than the cost of building Skylon. It's for this reason that most schemes for supersonic airlaunch involve sticking some rockets on an existing subsonic aircraft for a rocket zoom out of the atmosphere, bodging is cheaper.
So if you want to do hypersonic air launch, as per the thread, a bodged B1 would be cheaper than a new aircraft. Should the USAF wish to do such a crazy thing, of course REL would be contracted for the engine, and paid handsomely for it, no doubt it would have to be the notional US subsidiary supplying the notional US Skylon airframer being contracted.
AFAIK the only one currently being talked about is the XS1 project from DARPA.

That is looking to go to M10 with a 3000lb payload. If you can pack an ELV in 3000lb then that would pretty much fit the bill.

The X15 did get to M6.15 in the mid 60's.

The B1B is not  rated beyond about M2.25 (which is what the a version got to). If you're air breathing anyway you'd go with the LAPCAT engine instead and only have to worry about LH2 storage, not both LH2 and LO2.

The idea of airborne launch assist (both sub and supersonic) has been discussed at length on this site and on various news groups (primarily sci.space.tech) for the last 25 years.

You might like to read some of that before commenting further.  :(

Hasn't effectively all US hypersonic research been canned outside of the project you've mentioned above. The only thing I've seen talked about in recent years is developing something a some point from the Waverider project.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #26 on: 06/30/2014 02:46 pm »
Making a "point" the B-1B/A that folks keep missing:
"Payload: 125,000 lb (56,700 kg) ; internal and external ordnance combined"

That's split between two forward and one aft bomb-bay, (seperated by a fuel tank) and several external payload hard-points. Any SINGLE point can "probably" handle around 4,000lbs, and it you're going to get anywhere NEAR a decent LV you have to find/build a way to tie multiple hardpoints together with a "carry-pylon" AND the fact that it's external is going to seriously mess with your engine inlet airflow. (Supersonic is going to be tough if possible at all) IF you use "just" the bays you still need a specialized "pylon" structure to tie the hard-points together AND cover over the bay doors which would have to be removed. A LOT of work in other words, for not so much effect.

The MAIN problem with any existing airframe is the amount of modification needed to turn it into a carrier aircraft. Price and difficulty go up as your speed of seperation does. AirLaunch priced the conversion of a 747 to their launch system to around 20 million dollars IIRC, (with the "side" benefit of being capable of still carrying cargo AND being a "fire-tanker" aircraft as secondary incomes) and the "difficulty" and price would skyrocket from there for something supersonic, which currently none "usable" exist, let alone something hypersonic :)

'Course "I" know the answer to the problem :) (Really, don't we all at some point? :) )

In aerospace large is expensive, "fast" is even more expensive, just so everyone is on the same page though, in "air-launch" your top-three things you want to achieve are in order:
1) Speed
2) Altitude
3) AoA (Angle-of-Attack in comparision to the "local" horizon. The higher the better)

So of course a "nominal" rocket Launch Vehicle 1st stage is going to be somewhere between 40-to-70 degrees AoA, at an altitude of over 200,000ft and a speed of over Mach-6 (nominally Mach-10) to put a second stage and payload into LEO. That's damn tough to "beat" with an aircraft, probably greatly difficult to match even but that's "about" what Skylon is planning give or take a few percentages. From there its not more airbreathing and rocket all the way to orbit. Which only makes sense really because prolonged hypersonic airbreathing/travel only get tougher the longer you do it.

But Skylon is designed to be an SSTO, (Single Stage To Orbit) vehicle, and despite JS-19 claim that fewer stages is better SOMETIMES that's not so true. Besides the thread topic is using a hypersonic aircraft as a LEO launcher :)

The "question" comes down to how much 'hypersonic' aircraft do you need?
Interestingly enough, looking at the Zubrin/Clapp Analog article on the "Black Horse" LV has some interesting figures in it. (http://risacher.org/bh/analog.html) Specifically figures 2 and beyond where they did a "Trade Study" of 4 different propellant types and adding air-breathing engines to the vehicle to achieve "launch" speeds of Mach 0.8, 3.0, and 5.5. From the article:
"We assumed that the subsonic L/D (Lift/drag) for APT (Black Horse) vehicles was equal to 10, supersonic L/D was set equal to 3. Rocket engines were assumed to have a T/W of 60, jet engines a T/W of 8. Tanks were assumed to have a mass fraction of 4% of the propellant they contain if the propellant was water density; this fraction scaling inversely with the 2/3 power of propellant density."

Problem is then the APT/BH vehicle has to carry those airbreathing engines all the way to orbit and back, not to mention the added mass to the vehicle for structure and systems. That would be where a carrier aircraft comes in to the picture. What kind of carrier aircraft? Well lets look at our old buddy the B-1B Lancer...

First we get rid of anything we do not need... Like the crew, most of the airframe except for the landing gear, a couple of fuel tanks and the four F101-GE-102 afterburning turbofans. Now mount the already "podded" engines onto a frame carrying the landing gear and fuel tanks (add some space for some "additive" systems like a tank of LOX and a tank of water, we'll need variable inlets to get the podded engines back up to B-1A operation at Mach-2.2 and probably some more landing gear to carry all the mass) and attach the ATP/BH to the top using the bomb shackles/hardpoints we also kept from the B-1B. The ex-B1 frame has a minimum autopilot system to get it back from where it's dropped off to base using either parafoils or extendable wings, (open-or-closed wings are lighter than actual "variable" wings) and interfaces directly with the ATP/BH vehicle who's pilot flies both vehicles to the seperation point.

The water/LOX is used for Mass Injection Pre-Compressor Cooling (MIPCC) for added thrust and to allow the nominally Mach-2.2 turbofans to achieve speeds up to Mach-5 at high altitude, at that point the pair is put into a climb at full throttle, (AoA @70 degrees) and the ATP/BH fires its rockets and the two seperete. (With no real "lift" of its own the engine-sled will drop away while the ATP/BH still will be getting some lift from its wings ensuring seperation) The engine-sled drops to a lower altitude deploys parafoils or wings and flies back to base to be checked out and then mated to another ATP/BH for the next flight.

"Better" would be to not use "lifting" flight at all and remove all the wings-and-wheels and just go for a near vertical trajectory from a vertical launch using MIPCC and jet engines to reach staging at Mach-5 and 150,000ft or so where the hypersonic lifting body "ATP/BH" takes over on rocket power to orbit. First stage flies back to a vertical landing and is quickly checked out and ready to go within hours at most. See, easy :)

Randy

From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #27 on: 06/30/2014 05:01 pm »
As we are talking about the future here why not go the whole hog if you're going to want a big airframe surely the Long Range Strike Bomber whatever that turns out to be would be more appropriate than a B1-B.
« Last Edit: 06/30/2014 05:04 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #28 on: 06/30/2014 07:20 pm »
As we are talking about the future here why not go the whole hog if you're going to want a big airframe surely the Long Range Strike Bomber whatever that turns out to be would be more appropriate than a B1-B.

Probably not there seems to be less of a trend towards heavy aircraft being supersonic so its more likley the LRSB will be slower (and more stealthy) rather than faster. Right now it looks like the LRSB is the "last-hope" for the Blended-Wing-Body aircraft to see the light of day... Someday :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #29 on: 06/30/2014 09:18 pm »

As we are talking about the future here why not go the whole hog if you're going to want a big airframe surely the Long Range Strike Bomber whatever that turns out to be would be more appropriate than a B1-B.

Probably not there seems to be less of a trend towards heavy aircraft being supersonic so its more likley the LRSB will be slower (and more stealthy) rather than faster. Right now it looks like the LRSB is the "last-hope" for the Blended-Wing-Body aircraft to see the light of day... Someday :)

Randy

The USAF have hinted it will be supersonic.

http://breakingdefense.com/2014/06/air-force-keeps-mum-on-new-bomber-rfp/

Offline Asteroza

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #30 on: 06/30/2014 11:22 pm »
For reference, a B-1B-esqe system seemed to have been proposed.

Using a civil variant of the TU-160 Blackjack bomber called the TU-160SK, there was an air launched LV called Burlak (later improved variant called Diana-Burlak after germany became involved). TU-160 had variable intakes so nominally can go faster than a B-1B in theory. The conversion suggests that the TU-160SK had a centerline external LV payload, with a carrier pylon closely hung and spanning all the former bomb bays. Burlak was predicted to be able to do 700 Kg to equatorial LEO, 1100 Kg for Diana-Burlak.

http://www.aerospaceguide.net/burlak.html

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #31 on: 07/01/2014 10:48 am »
"Better" would be to not use "lifting" flight at all and remove all the wings-and-wheels and just go for a near vertical trajectory from a vertical launch using MIPCC and jet engines to reach staging at Mach-5 and 150,000ft or so where the hypersonic lifting body "ATP/BH" takes over on rocket power to orbit. First stage flies back to a vertical landing and is quickly checked out and ready to go within hours at most. See, easy :)
TBF at M5 almost anything has some aerodynamic lift, the question is do you want to use it?

I think you've hit the nail on the head that "modding" an aircraft to get to M5 is going to be nightmareishly complex and building one from scratch eyewateringly expensive.  :( The "launch assist platform" architecture still looks quite good for this, ideally with minimal changes to the engine nacelles if possible.

AFAIk the only thing that comes close to this plan (in the US) is the DARPA Experimental Spaceplane 1 programme, but I'm not sure if there's been any action on it lately. :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline high road

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #32 on: 07/01/2014 11:35 am »

The big problem with airlaunch is the development cost. So a good launcher is capable of doing more than just space launch. Skylon will be used for supersonic/hypersonic travel as wel as launching stuff into LEO. The ALTO crossbow design was intended to be used as a conventional airplane, a mobile missile launcher, and what not. The sales pitch is more convenience for passengers and airline companies. Launching things into space is only a small part of what it does. (Great infographics in the L2 section, btw).

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #33 on: 07/01/2014 01:13 pm »
The USAF have hinted it will be supersonic.

http://breakingdefense.com/2014/06/air-force-keeps-mum-on-new-bomber-rfp/

The Air Force "wants" a lot out of the LRSB. Supersonic cruise and/or dash is one of those aspects that keeps coming and going depending on who's asking the questions. Because of the conflicting goals of high-payload/high-speed and long range it seems less and less likely that "high-speed" is going to be supersonic as high-subsonic keeps coming out ahead on fuel econmy. Then there is the whole "UAV versus Manned versus Stand-off versus Stealth..." infighting going on.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #34 on: 07/01/2014 01:19 pm »
For reference, a B-1B-esqe system seemed to have been proposed.

Using a civil variant of the TU-160 Blackjack bomber called the TU-160SK, there was an air launched LV called Burlak (later improved variant called Diana-Burlak after germany became involved). TU-160 had variable intakes so nominally can go faster than a B-1B in theory. The conversion suggests that the TU-160SK had a centerline external LV payload, with a carrier pylon closely hung and spanning all the former bomb bays. Burlak was predicted to be able to do 700 Kg to equatorial LEO, 1100 Kg for Diana-Burlak.

http://www.aerospaceguide.net/burlak.html

The Blackjack also has a bit more space between the engines which relieves the intake issues with an externally carried pod. The main issue with the Burlak/Diana-Burlak as far as I can tell is the Blackjack doesn't get a very high AoA for release leaving that to aero-propulsive manuevers by the LV which hurts your payload to orbit. (And the fact the "civil" Blackjack is pretty far fetched at the moment)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #35 on: 07/01/2014 01:38 pm »
"Better" would be to not use "lifting" flight at all and remove all the wings-and-wheels and just go for a near vertical trajectory from a vertical launch using MIPCC and jet engines to reach staging at Mach-5 and 150,000ft or so where the hypersonic lifting body "ATP/BH" takes over on rocket power to orbit. First stage flies back to a vertical landing and is quickly checked out and ready to go within hours at most. See, easy :)
TBF at M5 almost anything has some aerodynamic lift, the question is do you want to use it?

Every little bit helps right? :) Actually much beyond Mach-5 your heating and aeroloads are becoming so much of an issue you're ending up designing and building a hypersonic "aircraft" as WELL as an orbital launch vehicle. Which can be both good and bad depending on what you want out of the design, however in most cases what you "have" will not be very good as low-supersonic or subsonic speeds anymore which is an issue for something that "takesoff" on its own :)

A "spaceplane" that can fly from zero-to-lightoff-point is going to be a very different creature from something that has hypersonic/high-supersonic lift and control. It's the difference between the APT/Black-Horse and somthing like Bud Reddings "Spacecruiser" vehicle. The former can go from zero to maybe Mach-3 "efficently" enough that getting to Mach-5 is just a matter of power-to-weight, the latter can't take off on its own or even "fly" at low-supersonic/subsonic speeds without some help. (In its case a parafoil)
http://www.up-ship.com/apr/extras/scruiser1.htm
http://www.astronautix.com/craft/spauiser.htm
Quote
I think you've hit the nail on the head that "modding" an aircraft to get to M5 is going to be nightmareishly complex and building one from scratch eyewateringly expensive.  :( The "launch assist platform" architecture still looks quite good for this, ideally with minimal changes to the engine nacelles if possible.

AFAIk the only thing that comes close to this plan (in the US) is the DARPA Experimental Spaceplane 1 programme, but I'm not sure if there's been any action on it lately. :(

XS-1 is supposed to be a straight "booster" platform which is why the criteria "varies" between Mach-6 and Mach-10 to "cover" the various booster stage ranges. I really don't see anything being built from it as despite all the "hype" about not wanting the restrict the design they pretty much HAVE to go with a rocket powered flyback stage to meet the requirements. And as we're all aware that's "been-done" a dozen times already and nothings been built.

It's why the idea of Launch Assist Platforms keep coming back up, yes it's really a "stage" and yes normally it's going to be a pain to work with because you will not get the full performance you WANT, but you also won't be paying as much to build an entire "vehicle" as you normally would.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #36 on: 07/01/2014 01:57 pm »
One thing that's a big problem with hypersonic flight is the huge heat build up on the airframe. I have a hunch that any advanced design in the future might be using metamaterials as the solution to this particular issue. The large heat build up & strain on the airframe has been one of the main limitations on sustained hypersonic flight (as touched on in the link below). As a launch platform I would think sustained hypersonic velocities would be best.

http://phys.org/news/2012-04-darpa-hypersonic-glider-anomaly.html
« Last Edit: 07/01/2014 02:16 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #37 on: 07/01/2014 03:09 pm »
The big problem with airlaunch is the development cost. So a good launcher is capable of doing more than just space launch. Skylon will be used for supersonic/hypersonic travel as wel as launching stuff into LEO. The ALTO crossbow design was intended to be used as a conventional airplane, a mobile missile launcher, and what not. The sales pitch is more convenience for passengers and airline companies. Launching things into space is only a small part of what it does. (Great infographics in the L2 section, btw).

Good points, however:
1) Skylon will NOT be useable fo supersonic/hypersonic travel, it's an orbital launch vehicle ONLY. This is a key point with Skylon.

In addition to the ALTO information on L2 I'd recommend reading this report which though nominally on the ALTO study itself also is known as Cargo Rocket Space System Box Wing or CRoSSBoW Air Launch To Orbit concept.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070002822.pdf
http://thehuwaldtfamily.org/jtrl/research/Space/Launch%20Vehicles/Air%20Launch/Air%20Launch%20To%20Orbit%20-%20ALTO%20-%20Crossbow-concept,%20MSFC.pdf

On page 9 of this study under the paragraph title of "Economics" it gets right down to the nitty gritty where the actual ECONOMIC factors of Air Launch are explained, examined and expounded upon :) Two main key points is that 1) Air Launch Carrier Aircraft MUST substantially reduce launch costs, And 2) the Carrier Aircraft MUST have a continual utility beyond Launch Services.

Simply put if Air Launch doesn't reduce launch costs then what's the point? And "economy" also tells you that for at least the first "little-bit" any launch business is going to be only a small segment of your operations and if that's ALL your "aircraft" can do then you are going to be taking a serious hit monitarily from "sitting around" waiting on payloads. Hence both "available" and "custom" aircraft would "tend" to have other uses as well as LV carrier use. Or you'd think so anyway but in reality the idea of an air-launch carrier aircraft being able to "multitask" doesn't get much attention.

The main "point" always seems to be find the "best" method of achieving effective "air-launch" along with efficeincy:
https://wiki.umn.edu/pub/AEM_Air_Launch_Team/LaunchTrajectoryDesign/aiaa2001-4619.pdf
"Economy" often seems "thrown-in" if mentioned at all.

The "key" efficiency factors end up being
1) Speed
2) Altitude
3) AoA

"Economics" if considered at all dictated trying to use the best "available" airframe, either civil or military and then using some sort of method to optimize at least two of the above three criteria. Normally since all current airframes are subsonic and there is little change of improving performance enough to reach a critical speed then altitude or AoA were favored. Yet the argument was made and accepted that a "custom-built" carrier aircraft could be just as "economical" hence the WhiteKnight and StratoLaunch aircraft were built.

"Converted" commercial and military aircraft would for the most part still be able to carry "normal" cargo loads and in certain specific instances would have added operational modes. (Fire Tanke ability when a carrier aircraft has liquid storage and "balancing" systems such as the AirLaunch 747)

"Custom" aircraft though not so much though it should be pointed out that aircraft like the WhiteKnight and StratoLaunch COULD carry "podded" cargo in place of their LV cargos. It hasn't been suggested that they do and given the rather sharp focus of the "owners" it might never be. However a similar concept called Configurable Air Transport System (CATS) proposed by Mike Sneed  would offer somewhat similar advantages and can be used as an example:
http://mikesnead.net/resources/cat/tech_presentation_configurable_air_transport.pdf
http://mikesnead.net/resources/cat/tech_paper_configurable_air_transport.pdf

Somewhat in contrast though the ALTO is a minimalist concept (and I agree the info in L2 is quite good! :) ) reducing the "carrier" aircraft to wings and engines which allows a much more versitile "aircraft" that is almost totally "configurable" to a users needs. Of course that's actually "downside" as well because getting such an "airframe" certified would be "fun" given how many things it COULD do but was not specifically designed and built for :) (I've been told that at least one FAA representative "felt-like-crying" at the thought of having to define the criteria for such an aircraft :) ) I'd like to see exactly what would be required though as the concept has a lot going for it as a "universal" airframe for various operations. I mean imagine not only a "podded" passenger and.or cargo aircraft that can be "changed" in minutes but a air launch carrier that can fly both the DreamChaser AND the Dragon-V2 :)

However I need to point out you STILL are "stuck" with only two out of the three factors mentioned above, speed still isn't there and for that you can't really use a "modular" platform to achieve.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #38 on: 07/01/2014 03:11 pm »
One thing that's a big problem with hypersonic flight is the huge heat build up on the airframe.
True.

So why do it?

There is a fairly extensive series of threads on this (on this site and in the various sci.space.* newsgroups)
The key take away is
                         

                         launch is not cruise.

This is why Virgin Galactic plan to build a "Mach Three" space plane out of carbon fibre composite (and some ablatives) for a few secondsand SR71 had to be built out of Titanium for sustained high Mach flight.

What you need for a vehicle to survive the 4 hours from Brussels to Sydney (IE LAPCAT) at M5 is a very different proposition to what you'd need for (in theory) a "dash" from say M2.2 (which Concorde did uncooled using an RR58 Aluminium alloy skin for about 30 years) to M5+ for (maybe) 60 secs before beginning to decelerate back down again.   :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #39 on: 07/01/2014 03:21 pm »
One thing that's a big problem with hypersonic flight is the huge heat build up on the airframe. I have a hunch that any advanced design in the future might be using metamaterials as the solution to this particular issue. The large heat build up & strain on the airframe has been one of the main limitations on sustained hypersonic flight (as touched on in the link below). As a launch platform I would think sustained hypersonic velocities would be best.

http://phys.org/news/2012-04-darpa-hypersonic-glider-anomaly.html

Actually you want the "velocity" but you want to avoid doing those speeds as much as possible INSIDE the atmosphere :)

Above Mach-5 (more to the point things start getting complicated after Mach-3 and REALLY complicated after Mach-4) you want to really start thinking of getting out of the atmosphere as much as possible to reduce the heating and aerodynamic loading. Beyond that "practical" airbreathing propulsion after Mach-5 gets more and more complicated as your speed goes up. A normal (subsonic combustion) ramjet can be used up to about Mach-8 if you're really, really lucky. After that you have to go to some type of supersonic combustion ramjet and those have proven to be problimatical at best. (Strangly enough its been known for quite some time that rather than "internal-combustion" SCramjets, after about Mach-6 it actually becomes easier and more efficent to use "external-combustion" where the shape of the vehicle and the hypersonic "Mach-shock" wave are used as the "engine" surfaces. This is a bit easier and both greatly reduces drag and provides extra lift at hypersonic speeds)

For an LV also getting up and out of the atmosphere after Mach-5 greatly reduces the seperation issues for the next stage.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #40 on: 07/01/2014 03:28 pm »
One thing that's a big problem with hypersonic flight is the huge heat build up on the airframe.
True.

So why do it?

Because its there! No wait, wrong mountain... :)

I think this is a common misconception that ends up going back to "airbreathing" to orbit ideas such as NASP etc. When some folks talk or think about "hypersonic" flight they tend to make the "assumption" that it is in the atmosphere rather than being a "velocity" factor.

What you're doing for a LAUNCH VEHICLE is "hitting" those speeds (Mach-5+ or Mach10+) for a short time to facilitate the launch and then dropping down to slower speeds for the return flight.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline cordwainer

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #41 on: 07/01/2014 03:34 pm »
Seems like some kind of supersonic turbo-rocket would be more effective. Maybe a using a high altitude launch of a solid fuel air augmented rocket launched from a mothership aircraft would be more practical than a "hypersonic" craft. I would expect at high enough altitude Mach 4 might be sufficient to get you small payloads into space.

Offline lkm

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #42 on: 07/01/2014 03:43 pm »
Can I just point out that I never suggested moding a B1 to do hypersonic airbreathing. My thinking was airbreathing to mach 2+, whatever the limit of the airframe, and then rocket zoom out of the atmosphere to release the payload safely then glide back.
The payload would be something like  a Pegasus at 20mt for space launch or a hypersonic strike weapon, either way carried externally from the hardpoints as the bomb bays would be cryogenic fuel tanks. 

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #43 on: 07/01/2014 05:04 pm »
Can I just point out that I never suggested moding a B1 to do hypersonic airbreathing.

No you can't, and further "just" because its your idea doesn't mean WE can't interpret any way we want to! So there :P

Quote
My thinking was airbreathing to mach 2+, whatever the limit of the airframe, and then rocket zoom out of the atmosphere to release the payload safely then glide back.
The payload would be something like a Pegasus at 20mt for space launch or a hypersonic strike weapon, either way carried externally from the hardpoints as the bomb bays would be cryogenic fuel tanks. 

"Limit" of the airframe is right :) Pretty much even the B-1 can't pull off manuevers that complicated when flying a heavy payload. I'm not even sure the airframe could handle the extra load of a rocket motor without serios beefing up. Pretty much with a "standard" airframe you're limited to a "zoom" climb under full AB and then release. The fact of the matter is that most airframes aren't built to handle loads like that because they don't normally "do" those manuevers for their job.

Given the constraints it makes "sense" in most cases to try and optimize to what the airframe can do rather than try and "fix" the problems. On the other hand it makes probably MORE sense to simply come up with an airframe that CAN do what you want, or at least a "system" that will get you as close as possible :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #44 on: 07/01/2014 06:05 pm »
Seems like some kind of supersonic turbo-rocket would be more effective. Maybe a using a high altitude launch of a solid fuel air augmented rocket launched from a mothership aircraft would be more practical than a "hypersonic" craft. I would expect at high enough altitude Mach 4 might be sufficient to get you small payloads into space.

Depends really. An ATR would require an engine development program as well, even though we have several "dozen" already planned, built and tested "motors" none of them have been flight tested as of yet. Which is why I suggested using "off-the-shelf" engines with "bolt-on" mods. (In fact the Boeing Small Launch Vehicle, http://aviationweek.com/awin/boeing-unveils-air-launched-space-access-concept, planned on using a MIPCC enhanced turbojet as the "first" stage for pretty much the same reasons... Then they went off into "la-la" land with SCramjet powered second stage...)

Mach-4 at around 100,000ft+ is a good "start" for a couple of rocket powered stages, it might, "might" give you enough margin to allow total recoverability. As far as "I" see though any use of solids puts you right out of the "economy" equation though.

As for economics I'm not sure a small launcher can "afford" a carrier aircraft unless its simply "dumping" them out the back of an existing airframe at around 10,000ft or so. (Think C-130 at best) Beyond that I highly suspect that LAP is going to be required for small launchers to be econmical at all. As a thought-experiment/BOTE exercise I put some numbers together for a Mach-1.5 ground "air-cannon" LAP with a ramjet second and rocket third stage, along with a Jet-LAP TSTO and an Air-Launch TSTO (afore mentioned C-130) small sat launch vehicles and frankly the number were marginal unless I could get a pretty high (weekly) launch rate. I made a good number of assumptions to make them work but frankly there's a reason why my wife does the budget and not me :)

It comes down to how much someone would be willing to pay to ORBIT a "small-payload" and as Jim has pointed out currently they really don't PAY anything so why switch if they dont have to?
(But then Jim and I get into that whol "useful-payload" discussion and things go down hill from there :) )

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #45 on: 07/01/2014 06:09 pm »
Wasn't the Soviet Union supposed to be developing a hypersonic aircraft for satellite launch, or did I imagine that?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #46 on: 07/01/2014 06:43 pm »
Wasn't the Soviet Union supposed to be developing a hypersonic aircraft for satellite launch, or did I imagine that?

You're imagining things, really sit down and take a deep breath, close your eyes and let the nice men in the white coats fit you for your nice padded cell... :)

The Spirel 50/50: http://www.aerospaceguide.net/spaceplanes/spiral.html
http://www.spacebanter.com/showthread.php?t=54715

Depending on which "version" you're looking at the carrier aircraft was either high-supersonic (Mach-4) or low hypersonic (Mach-6) at release of the second stage vehicle which would be outfitted with either the Mig105-11/13 space plane of a satellite.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #47 on: 07/01/2014 07:34 pm »

Wasn't the Soviet Union supposed to be developing a hypersonic aircraft for satellite launch, or did I imagine that?

You're imagining things, really sit down and take a deep breath, close your eyes and let the nice men in the white coats fit you for your nice padded cell... :)

The Spirel 50/50: http://www.aerospaceguide.net/spaceplanes/spiral.html
http://www.spacebanter.com/showthread.php?t=54715

Depending on which "version" you're looking at the carrier aircraft was either high-supersonic (Mach-4) or low hypersonic (Mach-6) at release of the second stage vehicle which would be outfitted with either the Mig105-11/13 space plane of a satellite.

Randy

It's very frustrating trying to do any research into this particular subject and hypersonic aviation in general online as the whole topic seems infested with exaggerated claims and projects that either never existed or never got off the drawing board. That said there seems to be more interest and money being poured into this area than ever before and this combined, as this new article on Space Review says, maybe the time of the airborne launcher is here at last.

http://www.thespacereview.com/article/2543/1

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #48 on: 07/01/2014 08:46 pm »

It's very frustrating trying to do any research into this particular subject and hypersonic aviation in general online as the whole topic seems infested with exaggerated claims and projects that either never existed or never got off the drawing board. That said there seems to be more interest and money being poured into this area than ever before and this combined, as this new article on Space Review says, maybe the time of the airborne launcher is here at last.

http://www.thespacereview.com/article/2543/1
"a combination of nitrous oxide and acetelyene, mixed together in the same propellant tank and “slightly chilled” below room temperature, Clapp said. "

That's kind of sporty.

Acetylene is notorious as being very shock sensitive.  :( I wonder if they will be using some kind of catalyst involved?

Note the bigitem. No new aircraft, only ones that can be assigned without complex (IE recertifiable) changes.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline IslandPlaya

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #49 on: 07/01/2014 09:42 pm »
Quote
Acetylene is notorious as being very shock sensitive.
I seem to remember my old metalwork teacher, Gripper Grundy, fair throwing around the acetylene cylinder when changing it in when we were cutting up some metal sheet...

Offline AnalogMan

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #50 on: 07/01/2014 11:35 pm »
Quote
Acetylene is notorious as being very shock sensitive.
I seem to remember my old metalwork teacher, Gripper Grundy, fair throwing around the acetylene cylinder when changing it in when we were cutting up some metal sheet...

That's fine.

Acetylene cylinders are packed with a porous medium (usually agamassan these days) and half filled with an organic solvent in which the acetylene gas dissolves (and renders it non-explosive).  The porous material absorbs gaseous acetylene that is not in solution to prevent it from forming larger unstable volumes.  This technique is effective in making acetylene cylinders safe to handle.

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #51 on: 07/02/2014 06:37 am »


It's very frustrating trying to do any research into this particular subject and hypersonic aviation in general online as the whole topic seems infested with exaggerated claims and projects that either never existed or never got off the drawing board. That said there seems to be more interest and money being poured into this area than ever before and this combined, as this new article on Space Review says, maybe the time of the airborne launcher is here at last.

http://www.thespacereview.com/article/2543/1
"a combination of nitrous oxide and acetelyene, mixed together in the same propellant tank and “slightly chilled” below room temperature, Clapp said. "

That's kind of sporty.

Acetylene is notorious as being very shock sensitive.  :( I wonder if they will be using some kind of catalyst involved?

Note the bigitem. No new aircraft, only ones that can be assigned without complex (IE recertifiable) changes.

Well if they are going to put that F-15E imagine how much larger the payload capacity could be on an evolved version if carried on a larger future airframe.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #52 on: 07/02/2014 07:04 am »
Well if they are going to put that F-15E imagine how much larger the payload capacity could be on an evolved version if carried on a larger future airframe.
AFAIK the one of the reasons the F15 is liked is because it has a very high (for an aircraft) T/W ratio and can do high AoA climbs. I'm not sure if it can do fully vertical (relying on engine thrust alone) but well above 45deg to the horizontal.

You'll note it's an old design and AFAIK nothing comes close in that area because they were not designed to do so.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline IslandPlaya

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #53 on: 07/02/2014 10:21 am »
Quote
Acetylene is notorious as being very shock sensitive.
I seem to remember my old metalwork teacher, Gripper Grundy, fair throwing around the acetylene cylinder when changing it in when we were cutting up some metal sheet...

That's fine.

Acetylene cylinders are packed with a porous medium (usually agamassan these days) and half filled with an organic solvent in which the acetylene gas dissolves (and renders it non-explosive).  The porous material absorbs gaseous acetylene that is not in solution to prevent it from forming larger unstable volumes.  This technique is effective in making acetylene cylinders safe to handle.
Thanks for the info! I learn something new from you good folks every day.  :)

Offline Jim

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #54 on: 07/02/2014 10:24 am »

AFAIK the one of the reasons the F15 is liked is because it has a very high (for an aircraft) T/W ratio and can do high AoA climbs. I'm not sure if it can do fully vertical (relying on engine thrust alone) but well above 45deg to the horizontal.

It was one of the first operational fighters with a T/W>1.

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #55 on: 07/02/2014 10:24 am »

Well if they are going to put that F-15E imagine how much larger the payload capacity could be on an evolved version if carried on a larger future airframe.
AFAIK the one of the reasons the F15 is liked is because it has a very high (for an aircraft) T/W ratio and can do high AoA climbs. I'm not sure if it can do fully vertical (relying on engine thrust alone) but well above 45deg to the horizontal.

You'll note it's an old design and AFAIK nothing comes close in that area because they were not designed to do so.  :(

As you yourself say it is an old design. The average age of the USAF fleet is something like 24 years old & the F15 is contributing to that high average. As the USAF have indicated they want stealth everywhere it wouldn't surprise me if we don't see it replaced sooner rather than later.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #56 on: 07/02/2014 01:20 pm »
As you yourself say it is an old design. The average age of the USAF fleet is something like 24 years old & the F15 is contributing to that high average. As the USAF have indicated they want stealth everywhere it wouldn't surprise me if we don't see it replaced sooner rather than later.
Looking up the Wikipedia entry on thrust to weight ratio I see the T/W for the F15k is reckoned to be about 1.15 :1 while the newer design F22 is just a little better at 1.19:1 while none of the F35 variants listed is above 0.9:1

High rate of climb is useful for "scrambles" but I get the feeling stealth is prized much more and that tends to cut performance, not least because at > M1 the whole aircraft makes a good IR target, regardless of what radar coating or shaping has been used.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #57 on: 07/02/2014 01:29 pm »
As you yourself say it is an old design. The average age of the USAF fleet is something like 24 years old & the F15 is contributing to that high average. As the USAF have indicated they want stealth everywhere it wouldn't surprise me if we don't see it replaced sooner rather than later.
Looking up the Wikipedia entry on thrust to weight ratio I see the T/W for the F15k is reckoned to be about 1.15 :1 while the newer design F22 is just a little better at 1.19:1 while none of the F35 variants listed is above 0.9:1

High rate of climb is useful for "scrambles" but I get the feeling stealth is prized much more and that tends to cut performance, not least because at > M1 the whole aircraft makes a good IR target, regardless of what radar coating or shaping has been used.  :(

It wouldn't surprise if that dichotomy will not be resolved with the advances in stealth technology especially to deal with IR signature. I say this as it's pointless to have stealth in some areas of the electromagnetic spectrum but not others and that is why the holy grail seems to be broad spectrum stealth. I am hopeful that an airframe will arise that can take on this particular task from the F15.

DARPA have a lot more knowledge than us about what will arise in future and this launcher seems to be plug & play for a better use of words so it wouldn't surprise me if it was easily adaptable to future platforms.
« Last Edit: 07/02/2014 01:38 pm by Star One »

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #58 on: 07/02/2014 05:45 pm »
It wouldn't surprise if that dichotomy will not be resolved with the advances in stealth technology especially to deal with IR signature. I say this as it's pointless to have stealth in some areas of the electromagnetic spectrum but not others
True.
Quote
and that is why the holy grail seems to be broad spectrum stealth. I am hopeful that an airframe will arise that can take on this particular task from the F15.
That's more debatable. Again it won't be hypersonic either. IRL the nearest to a large M5 aircraft has been the XB70, designed to carry 50 tonnes of bombs to Moscow. That managed M3 in a cost effective stainless steel honeycomb ( but man what an RCS)
Quote
DARPA have a lot more knowledge than us about what will arise in future and this launcher seems to be plug & play for a better use of words so it wouldn't surprise me if it was easily adaptable to future platforms.
True but so what? will the new aircraft have a bigger payload to allow a bigger payload to orbit? Will it have a higher top speed? In either case I'd have to say doubtful. "Makes a good ELV launcher" is IMHO not at the top of any USG aircraft contractor (although obviously it's at the top of Stratolaunches  :) ).
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #59 on: 07/02/2014 07:10 pm »
It's very frustrating trying to do any research into this particular subject and hypersonic aviation in general online as the whole topic seems infested with exaggerated claims and projects that either never existed or never got off the drawing board.

The main problem is no one has found a "good" reason to build an actual hypersonic (cruise) aircraft and items that only "pass" (accellerate/decellerate) through it are more "usefully" powered by rocket engines. That has never stopped design and some testing but its never given enough reason to increase interest. 40+ years ago it was "assumed" that hypersonic flight would be just a step along the progression of speed, just like supersonic was. But hypersonic turned out to be a lot harder and a lot less "usefull" than people had assumed once we had more data on flight at those speeds. Similarly the use of hypersonic airbreathing for space launch was seen as easier to engineer than it turned out to be.

A good overview of the "thinking" can be found in this paper:
http://www.thefreelibrary.com/Origins+of+Hypersonic+Propulsion%3a+A+Personal+History.-a068507621

Two key thoughts you will note is that in the 1950s several highly credible scientist put forth the idea that there "was no natural limit to how fast an aircraft can fly" which significantly influanced high-speed aircraft thinking. (Leave aside the "how" of the question because that's "just" engineering after all :) )
The second was the idea of the SCRamjet engine which by 1957 had "math" to prove it COULD operate to speeds well over that of orbital, and you suddenly "see" how seductive all this becomes...

It still is as can be seen in some of the slides from this presentation from 2006, (note the presenter :) ):
http://www.sei.aero/eng/papers/uploads/archive/AIAA-2006-8056_present.pdf
(Edit: Found the "paper" refered to in presentation: http://www.sei.aero/eng/papers/uploads/archive/AIAA-2006-8056.pdf)
Simply put flying/airbreathing up to high-hypersonic speeds (Mach-12+) gives you the BEST payload to orbit fractions. Period.

The problem is actually GETTING to and maintaning those speeds in a "practical" way with an afforable airframe. And that IS the most serious problem because while the "math" says all the right things "real-world" issues like materials and actual operations say going past Mach-5 is really, really hard and really, really expensive.
Quote
That said there seems to be more interest and money being poured into this area than ever before and this combined, as this new article on Space Review says, maybe the time of the airborne launcher is here at last.

http://www.thespacereview.com/article/2543/1

Well not a "hypersonic" one at any rate, not yet :) And I still say they need to drop the whole "carrier aircraft" idea..

Randy
« Last Edit: 07/02/2014 08:16 pm by RanulfC »
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #60 on: 07/02/2014 07:43 pm »
It wouldn't surprise if that dichotomy will not be resolved with the advances in stealth technology especially to deal with IR signature. I say this as it's pointless to have stealth in some areas of the electromagnetic spectrum but not others
True.

Actually, its NOT true because "stealth" has always been a "compromise" situation. You HAVE to give up something in order to reduce your "emissions" to a level where stealth works. Stealth is the "art" of hiding as many emissions as possible so the enemy has a harder time finding you, but in order to make it "work" at all YOU have limit what "emissions" you provide in the first place. Not turning on your radar or using other "active" emissions systems is a big step, but then you MUST also control passive emissions such as radar-cross-section and IR. And the higher the "speed" the more you radiate. IR is especially difficult because you can't NOT supress IR for any significant length of time and the higher the "power" the higher the emissions you need to supress. This is especially true of air-friction! At speeds over Mach-1 current MISSILE sensors are capble of locking onto and tracking an aircraft by the heat generated over its leading airfoil edges, this only gets worse as speed increases.

And various IR tracking sensors on the aircraft themselves are much more capable than a missiles sensor.
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and that is why the holy grail seems to be broad spectrum stealth. I am hopeful that an airframe will arise that can take on this particular task from the F15.
That's more debatable. Again it won't be hypersonic either. IRL the nearest to a large M5 aircraft has been the XB70, designed to carry 50 tonnes of bombs to Moscow. That managed M3 in a cost effective stainless steel honeycomb ( but man what an RCS)

Worse actually as the "active-lift" of capturing the supersonic shockwave under the wings by folding the wingtips increased the RCS ten-fold by themselves! (Which is why a small "Quail" ECM-decoy can look to a radar as big as the B-52s which carried it! http://en.wikipedia.org/wiki/ADM-20_Quail)

Seriously the F-22 IS the "replacement" for the F-15 as the F-35 is supposed to "replace" the F-16, and both 'replacement' airframes are not in many ways as "capable" as the aircraft they are replacing. The only current military "planned" hypersonic vehicles are drones or weapons. There is no need forseen for any manned hypersonic vehicles in the forseeable future :(
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DARPA have a lot more knowledge than us about what will arise in future and this launcher seems to be plug & play for a better use of words so it wouldn't surprise me if it was easily adaptable to future platforms.
True but so what? will the new aircraft have a bigger payload to allow a bigger payload to orbit? Will it have a higher top speed? In either case I'd have to say doubtful. "Makes a good ELV launcher" is IMHO not at the top of any USG aircraft contractor (although obviously it's at the top of Stratolaunches  :) ).

Actually I'd be surprised if the government isn't looking at the StratoLaunch aircraft as a possible "test-bed" for testing ideas on modular strategic mobility and support aircraft as pointed to in the CATS concept I mentioned above. In a lot of ways it makes sense to move in that direction for both civil and military "heavy" aviation needs.

In general there is little interest in "supersonic" aircraft for civil and military use (the military really only "needs" speed to allow flexible engagement parameters, I.E. you can run when you don't want to fight or engage an enemy who's trying to run away, but the old "Interceptor" role is much less of a priority than manueverability is these days) outside of certain narrow and mostly un-economical uses. Hypersonics is only sees an "possible" should long-distance travel show a very high need for "shorter" travel times. This has actually not been the case since telecommunications allow almost as much flexiability with lower economic costs.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #61 on: 07/02/2014 08:04 pm »
As a note on aircraft and jet engine T/W and manuevers: The F-15 and F-16 were the first aircraft in the world that could actually ACCELLERATE in a vertical (90-degree) climb, though they had to have a "light" loading to do so. So called "Viking Departures" were all the rage of the 80s where they would hit the end of the runway about 100 feet off the ground and then go vertical and into full-AB and climb out of sight. And that was using the older, less powerful F100 model engines they initially came out with :)

Meanwhile civil turbofan engines have gone with higher and higher bypass ratios for more efficent cruise rather than shear power.

Jet engines, especially miltary low or medium-bypass models are still capable of very good T/W ratios. For example the F135 engine of the F-35 only gives an "installed" T/W (at a 50% fuel loading) of 1.07 while the engine itself is capable of engine alone has a T/W of 11.467! Granted this drops as you load "essentials" onto it, (such as fuel, framing, tankage, and avionics for example) but not so fast that you can't retain enough T/W to give a decent take-off accelleration to a LAP vehicle.

Then again that gets back into the whole "specialized" airframe stuff that Clapp noted in his presentation that tends to RAISE not lower costs. But you have to wonder if there isn't a point where that can be balanced out...

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #62 on: 07/02/2014 09:33 pm »
Worse actually as the "active-lift" of capturing the supersonic shockwave under the wings by folding the wingtips increased the RCS ten-fold by themselves! (Which is why a small "Quail" ECM-decoy can look to a radar as big as the B-52s which carried it! http://en.wikipedia.org/wiki/ADM-20_Quail)
Indeed, a 3 sided conductive metal reflector. You couldn't really design a better way to increase the RCS.  :(
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Seriously the F-22 IS the "replacement" for the F-15 as the F-35 is supposed to "replace" the F-16, and both 'replacement' airframes are not in many ways as "capable" as the aircraft they are replacing. The only current military "planned" hypersonic vehicles are drones or weapons. There is no need forseen for any manned hypersonic vehicles in the forseeable future :(
The F22 seems to be a bit better in the T/W ratio, but I'm not sure how that translates into actual payload size.
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Actually I'd be surprised if the government isn't looking at the StratoLaunch aircraft as a possible "test-bed" for testing ideas on modular strategic mobility and support aircraft as pointed to in the CATS concept I mentioned above. In a lot of ways it makes sense to move in that direction for both civil and military "heavy" aviation needs.

In general there is little interest in "supersonic" aircraft for civil and military use (the military really only "needs" speed to allow flexible engagement parameters, I.E. you can run when you don't want to fight or engage an enemy who's trying to run away, but the old "Interceptor" role is much less of a priority than manueverability is these days) outside of certain narrow and mostly un-economical uses. Hypersonics is only sees an "possible" should long-distance travel show a very high need for "shorter" travel times. This has actually not been the case since telecommunications allow almost as much flexiability with lower economic costs.
It's a very interesting point. How well you build a LV that slots into (or onto) an existing aircraft with minimal (ideally zero) modification.

It seems there are so few big freighters with a rear openable payload door in flight.  :(

Outside of aircraft you're back to cutting development cost by going to a stripped down LAP concept.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #63 on: 07/02/2014 11:09 pm »
For the military the reasons for developing Hypersonic vehicles appear to be that speed is seen as the next level of stealth. Also there has been a growing realisation that satellites are not the be all & end all of intelligence gathering as they suffer from both being predictable & vulnerable to increasingly sophisticated anti-satellite weapons. A capability was lost when the SR-71 went away and now maybe that capability is sought again. Once the military have the reason to spend money on this kind of research then hopefully secondary functions such as satellite launch can follow along on the coat tails so too speak.

I suspect you could launch a spaceplane something like the XS-1 from the StratoLaunch aircraft. In fact maybe rather than a hypersonic aircraft as launcher but instead it being the payload on a larger carrier aircraft.
« Last Edit: 07/02/2014 11:21 pm by Star One »

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #64 on: 07/03/2014 07:32 am »
For the military the reasons for developing Hypersonic vehicles appear to be that speed is seen as the next level of stealth. Also there has been a growing realisation that satellites are not the be all & end all of intelligence gathering as they suffer from both being predictable & vulnerable to increasingly sophisticated anti-satellite weapons. A capability was lost when the SR-71 went away and now maybe that capability is sought again. Once the military have the reason to spend money on this kind of research then hopefully secondary functions such as satellite launch can follow along on the coat tails so too speak.

I suspect you could launch a spaceplane something like the XS-1 from the StratoLaunch aircraft. In fact maybe rather than a hypersonic aircraft as launcher but instead it being the payload on a larger carrier aircraft.
The loss of on  demand imaging capability that went away when the SR71 was retired was why it was revived for a short time.

Historically the process has been (for reconnaissance aircraft) altitude --> speed + altitude + low RCS (but high IR signature) --> altitude +low RCS + low IR (drones).

The concept of "responsive space" is an attempt to shift the argument to an "on demand" launch system capable of putting small(ish) pre prepared (possibly modular) satellites) into LEO over a battlefield to give those capabilities

Your desire for a high altitude high speed vehicle is frankly fairly unlikely (IMHO) to happen.  :(
« Last Edit: 07/03/2014 07:48 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #65 on: 07/03/2014 08:56 am »

For the military the reasons for developing Hypersonic vehicles appear to be that speed is seen as the next level of stealth. Also there has been a growing realisation that satellites are not the be all & end all of intelligence gathering as they suffer from both being predictable & vulnerable to increasingly sophisticated anti-satellite weapons. A capability was lost when the SR-71 went away and now maybe that capability is sought again. Once the military have the reason to spend money on this kind of research then hopefully secondary functions such as satellite launch can follow along on the coat tails so too speak.

I suspect you could launch a spaceplane something like the XS-1 from the StratoLaunch aircraft. In fact maybe rather than a hypersonic aircraft as launcher but instead it being the payload on a larger carrier aircraft.
The loss of on  demand imaging capability that went away when the SR71 was retired was why it was revived for a short time.

Historically the process has been (for reconnaissance aircraft) altitude --> speed + altitude + low RCS (but high IR signature) --> altitude +low RCS + low IR (drones).

The concept of "responsive space" is an attempt to shift the argument to an "on demand" launch system capable of putting small(ish) pre prepared (possibly modular) satellites) into LEO over a battlefield to give those capabilities

Your desire for a high altitude high speed vehicle is frankly fairly unlikely (IMHO) to happen.  :(

We'll have to agree to disagree on that last point, from my reading of the situation I believe there will be sufficient interest in such a vehicle sooner rather than later that there will be some movement on the matter.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #66 on: 07/07/2014 05:01 pm »
In general there is little interest in "supersonic" aircraft for civil and military use (the military really only "needs" speed to allow flexible engagement parameters, I.E. you can run when you don't want to fight or engage an enemy who's trying to run away, but the old "Interceptor" role is much less of a priority than manueverability is these days) outside of certain narrow and mostly un-economical uses. Hypersonics is only sees an "possible" should long-distance travel show a very high need for "shorter" travel times. This has actually not been the case since telecommunications allow almost as much flexiability with lower economic costs.
It's a very interesting point. How well you build a LV that slots into (or onto) an existing aircraft with minimal (ideally zero) modification.

It seems there are so few big freighters with a rear openable payload door in flight.  :(

Well, "technically" any of them can be opened in flight... Once ;)
Seriously the most "efficent" looking Air-Launch system for use with current "air-freighters" seems to be the AirLaunch T-LAD system and modifying a "standard" airframe to accomodate a multi-barrel, underslung LV. Anything else is too much money and/or work to look economical. (StratoLaunch gets "away" with using a purpose built carrier aircraft simply because thier LV is going to be too big for any existing airframe)

In the main it allows you to keep "multipurposing" the airframe until and unless flight rates become high enough for launch to be your main business.

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Outside of aircraft you're back to cutting development cost by going to a stripped down LAP concept.  :(

Pretty much

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #67 on: 07/08/2014 07:12 pm »
As good a place as any to put this.

Quote
WASHINGTON — The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.

http://www.spacenews.com/article/military-space/41161afrl-to-establish-new-hypersonics-facility-at-arnold


Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #68 on: 07/08/2014 07:51 pm »
As good a place as any to put this.

Quote
WASHINGTON — The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.

http://www.spacenews.com/article/military-space/41161afrl-to-establish-new-hypersonics-facility-at-arnold
A new hypersonics research programme.

Who knows? In 50 years of tests of SCramjets they've got to 6 minutes of positive thrust.

We'll have to see if this turns out to be another money pit.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #69 on: 07/08/2014 08:50 pm »
As good a place as any to put this.

Quote
WASHINGTON — The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.

http://www.spacenews.com/article/military-space/41161afrl-to-establish-new-hypersonics-facility-at-arnold
A new hypersonics research programme.

Who knows? In 50 years of tests of SCramjets they've got to 6 minutes of positive thrust.

We'll have to see if this turns out to be another money pit.  :(

"Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #70 on: 07/08/2014 09:12 pm »
"Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.
Perhaps they might call it the "Skylon Lab?"

Just kidding of course. But that makes it look a lot more viable than what's happened historically.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #71 on: 07/09/2014 06:24 am »

As good a place as any to put this.

Quote
WASHINGTON — The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.

http://www.spacenews.com/article/military-space/41161afrl-to-establish-new-hypersonics-facility-at-arnold
A new hypersonics research programme.

Who knows? In 50 years of tests of SCramjets they've got to 6 minutes of positive thrust.

We'll have to see if this turns out to be another money pit.  :(

"Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.

Randy

I really doubt that will be the case, looking at how things have gone in this area.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #72 on: 07/09/2014 06:36 am »
I really doubt that will be the case, looking at how things have gone in this area.
Perhaps you could expand that comment?
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #73 on: 07/09/2014 12:25 pm »
I really doubt that will be the case, looking at how things have gone in this area.
Perhaps you could expand that comment?

Well would you say practical Hypersonic research in the US has had a positive outcome of late?

Unless you're going to follow the assumption I believe that some small number of individuals make that all the best stuff is classified. Such claims I would treat  with an extremely high degree of scepticism.

To be fair Hypersonic flight is a massively hard nut to crack, let alone to maintain flight at that speed for useful periods of time within the atmosphere without the vehicle being ripped to pieces and that's just one issue with it. That's why it has been clear to me that something like the infamous Aurora is nothing but an urban fairy tale.

It's good they have set a place like this up, just that I will keep my expectations low and hope to be pleasantly surprised.

What is your thinking here?
« Last Edit: 07/09/2014 12:42 pm by Star One »

Offline vulture4

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #74 on: 07/09/2014 07:50 pm »
I agree. The drag losses during hypersonic flight in the atmosphere are so high that for all but short-range missiles it is more practical to go into orbit. To the extent that air launch is practical, the rocket will likely separate from the aircraft at subsonic speed.

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Using a hypersonic aircraft as a LEO launcher
« Reply #75 on: 07/09/2014 09:16 pm »
AFRL launches hypersonic branch at AEDC

Posted 7/3/2014   Updated 7/7/2014  Email story   Print story

by Deidre Ortiz
Arnold Engineering Development Complex Public Affairs

7/3/2014 - ARNOLD AIR FORCE BASE, TENN. -- The relationship between the Air Force Research Laboratory and Arnold Engineering Development Complex's hypervelocity capabilities is paying dividends and leading to a more in-depth and scientifically broader collaboration.

In light of the success of several joint projects, AFRL leadership has decided to extend the organization's partnership with AEDC by establishing a new hypersonic research branch, to be known as the High Speed Experimentation Branch, here.

The branch will be directed by AFRL's Aerospace Systems Directorate, the home office for which is located at Wright-Patterson AFB, Ohio.

Plans for the High Speed Experimentation Branch have been in the works since the beginning of the year. The branch is expected to be set up in AEDC's von Kármán Gas Dynamics Test Facility by Oct. 1, 2014.

Former AEDC Executive Director Dr. Douglas Blake, who once served as deputy director for AFRL Air Vehicles Directorate, stated he expects the development of this branch to be beneficial for everyone involved.

"Ricky Peters, AFRL executive director, has been the primary force behind [starting the hypersonic research branch at AEDC]," he said. "This is a very positive development; both AFRL and AEDC will benefit. Our vision is to bring together the research talent of AFRL, the test and engineering expertise and facilities of AEDC and the academic linkages brought by new talent coming on board at The University of Tennessee Space Institute to form a national center of gravity in hypersonics."

Dan Marren, site manager at AEDC's Hypervelocity Wind Tunnel 9, shared Blake's sentiments, stating that this collaboration will create a center for hypersonic research that's unlike any other.

"For years we have relied on an outstanding collaboration with AFRL in the scientifically demanding work we do in hypersonics," Marren said. "I am thrilled that the new hypersonic branch at AEDC can take the pilot activity we began at White Oak to a new level -- bringing in several hypersonic disciplines -- and form the basis for what we do across our hypersonic test enterprise."

Glenn Liston, AFRL's High Speed Systems Science and Technology advisor, will be heading the High Speed Experimentation Branch as branch chief.

"AFRL is excited to grow our partnership with AEDC," Liston said. "This new branch will leverage our long-standing relationship."

Liston explained that the team's mission will be to conduct foundational and systems research in propulsion, aeronautics and structural applications providing technology maturation related to the hypersonic flight regime.

"For AFRL's benefit, the branch will use the AEDC facilities and expertise to conduct research in larger scales than what we can typically handle in the facilities at Wright-Patterson," he said. "One benefit to AEDC will be the ability to engage the testing and evaluation workforce in the research process, generating new knowledge for hypersonic systems, while improving their capability to test revolutionary new flight systems."

According to Liston, AFRL and AEDC will together facilitate the transition of high speed science and technology through testing and evaluation to fielded systems, serving the development of the nation's aerospace capabilities.

Marren said he looks forward to seeing what the future holds for hypersonic research as a result of this development.

"Having Glenn Liston from AFRL, Dr. John Schmisseur at UTSI and the multi-disciplinary test facilities and teams at AEDC will give the Air Force a never-before-realized advantage of having everything the nation needs to move hypersonics to the warfighter co-located and moving in one direction," he said.

http://www.afmc.af.mil/news/story.asp?id=123416772

Reading the full press release does make it sound like this is extremely serious effort in this area.
« Last Edit: 07/09/2014 09:19 pm by Star One »

Offline a_langwich

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #76 on: 07/10/2014 01:12 am »
"Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.
Perhaps they might call it the "Skylon Lab?"

Just kidding of course. But that makes it look a lot more viable than what's happened historically.  :(

Oh?  When did I miss a Skylon flight over Mach 3?  (Even an airframe completed sitting on the ground, actually, but we're talking about flight test success.)  How many of those six minutes of successful flight has REL / Skylon contributed? 

I'm continually amazed at how this forum picks "winners" and losers completely unrelated to actual, you know, wins and losses.

Maybe we can pick up this discussion in 2019 or so when (perhaps) Skylon will be ready to test themselves against actual hypersonic conditions.

Meaning no disrespect to Skylon--they are a talented and potentially wonderful newcomer, and maybe in time they will do great things.  Until then, six minutes of powered hypersonic experience trumps zero minutes in the accomplishment category.

(Incidentally, I'm speaking as a bystander, not affiliated with AFRL or AEDC.)




"Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.

Randy

Looks to me like it's a shuffling of the org chart:  in the past, perhaps the AEDC hypersonics facilities and personnel were attached to perhaps a "wind tunnel facilities" group or a "flight dynamics analysis" group, and the AFRL hypersonics research group contracted across organizations to get them to do work.  Now, the AF is recognizing the hypersonic research group is the major customer for the hypersonic test facility group, so it's putting them together.

Doesn't sound like there is anything actually new--same personnel, same test facility, just reporting to the AFRL group instead of to someone in AEDC. 
« Last Edit: 07/10/2014 01:15 am by a_langwich »

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #77 on: 07/10/2014 07:50 am »
Oh?  When did I miss a Skylon flight over Mach 3?  (Even an airframe completed sitting on the ground, actually, but we're talking about flight test success.)  How many of those six minutes of successful flight has REL / Skylon contributed? 

I'm continually amazed at how this forum picks "winners" and losers completely unrelated to actual, you know, wins and losses.

Maybe we can pick up this discussion in 2019 or so when (perhaps) Skylon will be ready to test themselves against actual hypersonic conditions.

Meaning no disrespect to Skylon--they are a talented and potentially wonderful newcomer, and maybe in time they will do great things.  Until then, six minutes of powered hypersonic experience trumps zero minutes in the accomplishment category.

it's Bayesian reasoning: priors may go down with experience as well as up. ;D
thermodynamics will get you in the end

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #78 on: 07/10/2014 11:06 am »
Well would you say practical Hypersonic research in the US has had a positive outcome of late?
You mean actual flight vehicles? Interesting question.

Various ramjets and rockets have hit M5 but AFAIK none went into service. So there's some practical experience there, although nothing human carrying.

But if you're talking supersonic combustion as well the situation gets much murkier, with nothing flying with positive thrust until 2004 at the earliest.  :(
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Unless you're going to follow the assumption I believe that some small number of individuals make that all the best stuff is classified. Such claims I would treat  with an extremely high degree of scepticism.
Beware anyone who's CV is so classified it's effectively uncheckable.
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It's good they have set a place like this up, just that I will keep my expectations low and hope to be pleasantly surprised.
A wise move.
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What is your thinking here?
Well putting the users of complex, difficult to move facilities (and their support technicians) in one place is usually a pretty good idea if you want to foster innovation.

OTOH...

You have to wonder how much autonomy they will have or if every decision will have to be referred back to Wright Patterson. Not what you want if you've been given clear goals and want to make fast progress. :(

The other thing to wonder is are they extending US hypersonic research or is it in fact more archeological engineering, trying to recover the actual practice of hypersonic research.

In either case time will tell.
« Last Edit: 07/10/2014 11:07 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #79 on: 07/10/2014 11:35 am »
Maybe we can pick up this discussion in 2019 or so when (perhaps) Skylon will be ready to test themselves against actual hypersonic conditions.
What discussion? You're doing the talking.
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Meaning no disrespect to Skylon--they are a talented and potentially wonderful newcomer, and maybe in time they will do great things.  Until then, six minutes of powered hypersonic experience trumps zero minutes in the accomplishment category.
I quite agree flight experience trumps any Powerpoint.  :)

SABRE is based on a combination of gas turbine, ramjet and liquid fueled rocket technology, dating respectively from the late 1930's, late 1930's and late 1920's. The specific LO2/LH2 propellant technology dates from   the late 1950's. All backed by extensive flight histories in aircraft, missiles and rockets.

Now supersonic combustion has 3? 5? flight tests that actually ignited (I can't recall if they all produced positive thrust)

SABRE looks complex but is relatively easy to analyze and test on open test stands. A SCramjet is chemo-thermodynamically very complex to analyze. It's starting and operating conditions make it very difficult to test in anything but a flight vehicle, although hopefully AEDC has those facilities. REL estimated to do SABRE as SCramjets would take maybe $10Bn in test facilities, so if AEDC has those capabilities (still in working order) it is (literally) a national treasure.

IOW Given the heritage that SABRE leverages there is a high probability that it will work because all it's parts have worked before in multiple designs over a 70 year period.

In contrast a SCramjet may work, if very carefully (and probably very conservatively) designed.

Returning to the topic title how soon to scale that up and build that into a flight vehicle capable of accommodating a payload? Note that it's doubtful the USAF would settle for a vehicle that can hit M5 for say 60 secs, ignite the LV engines and begin slowing down, which is all that a LEO LV actually needs (and which the XS1 is meant to be in the ball park for).

They will want cruise, and cruise multiplies the problems.  :(
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(Incidentally, I'm speaking as a bystander, not affiliated with AFRL or AEDC.)
I never doubted that.  :)
« Last Edit: 07/10/2014 11:37 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #80 on: 07/10/2014 03:20 pm »
Looks like we may now have a choice of potential candidate vehicles for the purpose of replacing the F-15 at the very least in the ALASA program down the line. If the F-15 is retired from the frontline I assume it will be replaced in this program as well?

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While the Air Force is expected to soon issue a request for proposals for its long-range strike bomber, a July 2 Congressional Research Service report made public Tuesday suggests that the service has already developed the aircraft through its classified budget.

The CRS report also indicated the new bomber may not even be a single aircraft, but is perhaps several aircraft working together. “Although long-range strike systems are typically thought of as bomber aircraft, the more general description is used because it is not yet clear whether the proposed Long Range Strike Bomber (LRS-B) is to be a single platform or a group of smaller systems working in concert,” CRS reported.

http://www.nextgov.com/defense/2014/07/surprise-air-force-may-have-already-developed-its-long-range-strike-bomber/88285/?oref=ng-HPriver

Actual report can be found on link.

http://fas.org/sgp/crs/weapons/IN10095.html?new
« Last Edit: 07/11/2014 01:41 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #81 on: 07/10/2014 07:43 pm »
Looks like we may now have a choice of potential candidate vehicles for the purpose of replacing the F-15 at the very least in the ALASA program down the line. If the F-15 is retired from the frontline I assume it will be replaced in this program as well?

Well you can expect them (the F-15/F-16) to continue in reserve for quite some time with upgrades, and this (ALASA) is more of a "reserve" mission anyway. As for the "multi-vehicle" LRSB I suspect that this means the AF is leaning towards either drones or a "mother" aircraft and drones. In either case I'm suspecting the actual "payload" available won't be all that great or organized to make an air-launch carrier out of it :)

Speaking in that direction btw, I meant to point out that a good "canidate" system to use FROM an air-launch carrier might be the Firefly systems "Beta" heavy: http://www.fireflyspace.com/vehicles/firefly-b

At 6ft diameter it would fit (along with a T-Lad system) under most cargo jets :)

For general hypersonic research what we probably need is a dedicated "X-plane" without making it AS "dedicated" as the most recent ones have been. Something like the STAR=Spacecruiser:
http://falsesteps.wordpress.com/2012/10/31/star-the-usafs-everything-spacecraft/
http://www.dod.mil/pubs/foi/Science_and_Technology/Other/883.pdf
http://www.freepatentsonline.com/6257527.pdf

Which it will be noted in the second report (and patent) that it was proposed to air-drop it from a C-130J (as well as off the back of an SR-71 :) ) and using a Rocket-Based-Combined-Cycle (RBCC) engine module allow it to fly at high-supersonic and hypersonic speeds. At least this would allow (even if unmanned) a SERIES of engine tests with various types of engines rather than picking "one" and ending up with either a success or failure.

There is seriously a lot more hypersonic research that the US could be doing but funding is so spotty and interest so fickle that getting anything done is pretty much a matter of luck more than anything else :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #82 on: 07/10/2014 09:22 pm »
Which it will be noted in the second report (and patent) that it was proposed to air-drop it from a C-130J (as well as off the back of an SR-71 :) ) and using a Rocket-Based-Combined-Cycle (RBCC) engine module allow it to fly at high-supersonic and hypersonic speeds. At least this would allow (even if unmanned) a SERIES of engine tests with various types of engines rather than picking "one" and ending up with either a success or failure.
Something that's not used up after every launch seems like a pretty good idea.
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There is seriously a lot more hypersonic research that the US could be doing but funding is so spotty and interest so fickle that getting anything done is pretty much a matter of luck more than anything else :)
This is why I wondered how much of this work would be less to do with new research and more to do with recovering lost capability. :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #83 on: 07/11/2014 03:43 pm »
Some interesting news here.

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In order to prove that the MDP metholody works, the team agreed to develop materials that can withstand extreme heat for the outer shell of a hypersonic aircraft, as it can travel more than five times the speed of sound. The group needs to be done within the next two-and-a-half years for the program's method to be deemed successful, so watch out for any hypersonic plane news from DARPA in 2016 or 2017.

http://www.engadget.com/2014/07/11/darpa-materials-program/
« Last Edit: 07/11/2014 03:49 pm by Star One »

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« Last Edit: 07/16/2014 03:08 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #85 on: 07/16/2014 03:22 pm »
Some more hypersonic related information.

https://www.fbo.gov/index?s=opportunity&mode=form&id=98ad53aa422228aa7fcd190c08b9653a&tab=core&_cview=0

Great, scramjets again. At least theres some other areas as well.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #86 on: 07/16/2014 04:15 pm »
Some more hypersonic related information.

https://www.fbo.gov/index?s=opportunity&mode=form&id=98ad53aa422228aa7fcd190c08b9653a&tab=core&_cview=0

Great, scramjets again. At least theres some other areas as well.

Randy

Yes I agree with you they seem quite stuck on scramjets for some reason.

Maybe a follow-on to the Waverider program.
« Last Edit: 07/16/2014 04:18 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #87 on: 07/16/2014 04:55 pm »
Some more hypersonic related information.

https://www.fbo.gov/index?s=opportunity&mode=form&id=98ad53aa422228aa7fcd190c08b9653a&tab=core&_cview=0

Great, scramjets again. At least theres some other areas as well.

Yes I agree with you they seem quite stuck on scramjets for some reason.

Maybe a follow-on to the Waverider program.

Oh the reason is pretty clear, I just don't see much logic in following a scramjet path to get there :)

Especially since they want "low cost flight testing"... On a scramjet? Please! What really kills me though is the speed ranges they are looking at (not mentioned) but for anything under Mach-10 you simply DO NOT NEED a SCramjet engine! A standard subsonic combustion ramjet would work for the stuff they are playing around with!

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #88 on: 07/16/2014 09:04 pm »
Want to speculate why they are looking at this again if there are alternative concepts for engine technology out there?

Speculate? Me? Why ever would I do such a thing? ;)

SCramjet engines are airbreathing engines that can in therory continue to accellerate indefinatly, how much is a missile that you launch at Mach-2 and impacts at Mach-20 "worth" to the military? Conversly, how much is an airbreathing engine that can go from zero to Mach-20+ worth as a part of a space launch system?

The problem though is how fast (and how far) can an OPERATIONAL SCramjet engine really work and is it actually "worth" the trouble? Because every indicator we've seen so far is that a working SCramjet engine is going to be really, really expensive and of doubious use at best. But what is the "alternative" then? Rocket motors are good, so long as the propellant lasts. Ramjets are good up until around Mach-5 then the design gets much tougher, (my contention is that they are LESS tough than SCramjets which is echoed by people who've actually worked on high-speed subsonic combustion ramjets, however...) and you have to get tricky with the inlet and exhausts to keep accelerating which is expensive. (But again I content not as expensive as the marginal SCramjet's have been) And conventional wisdom, (the same one that insisted that the only way to do airbreathing flight at speeds above Mach-5 mind you was to liquify the air and then burn it in a SCramjet to Mach-20+) insits that above Mach-7 a sub-sonic combustion ramjet won't generate positive thrust, and that the internal flow MUST then become supersonic. (Mind that the folks at Mardquart actually ran test engines up to Mach-8+ and the engineers could not see why you couldn't get positve thrust up till Mach-10 if you designed it right. Still that's ONLY Mach-10...)

At the end of the day though the alternatives don't hold that hope of continual accelleration that the SCramjet does so they tend to be considered a "default" rather than an alternative. So SCramjets will continue to get money and development because they ARE SCramjets while the alternatives will get regulated to a backup position that MIGHT get funded if anyone becomes convinced that the laws of physics simply won't allow SCramjets. (In otherwords no one is going to settle for a Mach-10 engine when they MIGHT possibly be able to get a Mach-20 one :) )

I suspect that SCramjets are a whole lot like "fusion" energy, awaiting that next breakthrough that will finally allow them to shine as much in fact as they do in theory... I'm just afraid that it will always be 20 years from today as well:)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #89 on: 07/17/2014 08:13 am »
The problem though is how fast (and how far) can an OPERATIONAL SCramjet engine really work and is it actually "worth" the trouble? Because every indicator we've seen so far is that a working SCramjet engine is going to be really, really expensive and of doubious use at best. But what is the "alternative" then? Rocket motors are good, so long as the propellant lasts. Ramjets are good up until around Mach-5 then the design gets much tougher, (my contention is that they are LESS tough than SCramjets which is echoed by people who've actually worked on high-speed subsonic combustion ramjets, however...) and you have to get tricky with the inlet and exhausts to keep accelerating which is expensive. (But again I content not as expensive as the marginal SCramjet's have been) And conventional wisdom, (the same one that insisted that the only way to do airbreathing flight at speeds above Mach-5 mind you was to liquify the air and then burn it in a SCramjet to Mach-20+) insits that above Mach-7 a sub-sonic combustion ramjet won't generate positive thrust, and that the internal flow MUST then become supersonic. (Mind that the folks at Mardquart actually ran test engines up to Mach-8+ and the engineers could not see why you couldn't get positve thrust up till Mach-10 if you designed it right. Still that's ONLY Mach-10...)
For a lot of laymen something not far short of 3x the top speed of an SR71 would be viewed as pretty impressive.

You wonder how often these guys talk to real aircraft builders

Quote
At the end of the day though the alternatives don't hold that hope of continual accelleration that the SCramjet does so they tend to be considered a "default" rather than an alternative. So SCramjets will continue to get money and development because they ARE SCramjets while the alternatives will get regulated to a backup position that MIGHT get funded if anyone becomes convinced that the laws of physics simply won't allow SCramjets. (In otherwords no one is going to settle for a Mach-10 engine when they MIGHT possibly be able to get a Mach-20 one :) )

I suspect that SCramjets are a whole lot like "fusion" energy, awaiting that next breakthrough that will finally allow them to shine as much in fact as they do in theory... I'm just afraid that it will always be 20 years from today as well:)
I suspect you're right.  :(

Of course a Skylon would make a great platform to drop SCramjets from to allow testing through the whole operating range.  :)

MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #90 on: 07/17/2014 10:50 am »
The one question for me that is outstanding in this matter is where does LM's engine concept that they were bigging up in Aviation Week in connection with the SR-72 figure in this. They certainly seemed to regard the idea as some kind of breakthrough in achieving hypersonic flight?

If there is nothing better out there you would think LM would be banging on the door of government, as the piece in AW seemed to imply that all they lacked was funding.
« Last Edit: 07/17/2014 11:07 am by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #91 on: 07/17/2014 01:52 pm »
The one question for me that is outstanding in this matter is where does LM's engine concept that they were bigging up in Aviation Week in connection with the SR-72 figure in this. They certainly seemed to regard the idea as some kind of breakthrough in achieving hypersonic flight?

If there is nothing better out there you would think LM would be banging on the door of government, as the piece in AW seemed to imply that all they lacked was funding.

Last part first: What makes you think that LM is not constantly banging on the government door looking for funding for various projects? :)

"Lack of funding" pretty much describes the way American hypersonic research is conducted on a continuing basis actually. Money seems to get freed up for various proposals only to be withdrawn later for various and sundry reasons. (To me most of those reasons seem to surround someone tacking SCramjet research onto the project at some point but I MAY be biased :) )

IIRC the "SR-72" engine was supposed to be based on a turbine-based-combined-cyle (TBCC) engine using a dual-mode ramjet engine for higher speed. Advertised speeds up to Mach-6 were forseen. But let me back up a bit, remember this TBCC is built around a duel-mode ramjet... And what would these duel modes be? Why subsonic combustion ramjet and... Yep, you guessed it, a supersonic combustion SCramjet...

I seem to recall the turbine base engine was supposed to be based on the GE Revolutionary Air Turbine engine which was a pretty standard turboramjet engine good from zero to around Mach-4. For the SR-72 drone the ramjet would be rebuilt to allow it to get up to around Mach-5 followed by the SCramjet cutting in and going up to Mach-6... Except they needed more funding to build the SCramjet portion of the engine, more testing and pretty much had/have yet to prove that you can actually RUN a SCramjet efficently at those speeds.

Aaarrggh! You're building an engine around a duel-mode ramjet... Why again? Lets see if the ramjet kicks in around Mach-4 and its designed at ALL decently it should be then capable of flying to Mach-6 with ease. What's the airframes proposed top speed? Mach-6? Then why the HELL would you even consider putting in a SCramjet you don't even NEED?

What? Oh of course, silly me, everyone knows that a hypersonic aircraft has to use a SCramjet engine because ramjets can only go, you know supersonic and not hypersonic well duh...

I'm going to use a phrase my wife found in a blog and is using for a new tagline: "My keyboard will not allow my forehead to go un-smacked!" Yep, that about sums it up I think...

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #92 on: 07/29/2014 07:22 pm »
Aaarrggh! You're building an engine around a duel-mode ramjet... Why again? Lets see if the ramjet kicks in around Mach-4 and its designed at ALL decently it should be then capable of flying to Mach-6 with ease. What's the airframes proposed top speed? Mach-6? Then why the HELL would you even consider putting in a SCramjet you don't even NEED?

What? Oh of course, silly me, everyone knows that a hypersonic aircraft has to use a SCramjet engine because ramjets can only go, you know supersonic and not hypersonic well duh...
I'd guess even a conservative approach of regular jet engines would get you to M2.2 or 2.4 and a ramjet to M3 would give you M5.4.

Which I'd call pretty good, but obviously for some people that's just not good enough.  :(

When the history of high speed flight is written I think hypersonic flight --> hypersonic combustion will go down in history with cruise = launch as one of the the great conceptual mistakes in vehicle design.   :(

But of course that won't give you the dream of air breathing to orbit.  :(

But my instinct is that even if you manage to inject your fuel into the airflow with minimal turbulence and you use H2 you just won't inject enough heat to the flow to get enough acceleration before you run out of fuel.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #93 on: 08/05/2014 06:45 pm »
New interview with Marilyn Hewson head of LM & spot how many times she mentions their investment in hypersonics, clue it's quite a few.

http://www.c4isrnet.com/article/20140805/C4ISRNET08/308050004/How-Lockheed-Martin-plans-compete-against-Google-Amazon

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #94 on: 08/05/2014 07:41 pm »

Oh?  When did I miss a Skylon flight over Mach 3?  (Even an airframe completed sitting on the ground, actually, but we're talking about flight test success.)  How many of those six minutes of successful flight has REL / Skylon contributed? 

I'm continually amazed at how this forum picks "winners" and losers completely unrelated to actual, you know, wins and losses.

That might be because the forum has a lot of smart people who can evaluate a concept even before it's flown?

Quote

Maybe we can pick up this discussion in 2019 or so when (perhaps) Skylon will be ready to test themselves against actual hypersonic conditions.

Meaning no disrespect to Skylon--they are a talented and potentially wonderful newcomer, and maybe in time they will do great things.  Until then, six minutes of powered hypersonic experience trumps zero minutes in the accomplishment category.
 

The Internal Combustion Engine has racked up trillions of hours of experience.

I still think the SABRE engine is more likely to get you to orbit.


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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #95 on: 08/05/2014 08:03 pm »
Supposing the launch demand gets to justify a hypersonic launch system, and suppose Skylon hasn't cornered this market.....

Rather than developing a hypersonic (or even supersonic) launcher to carry a rocket, how about developing a rocket to carry the wings, engines and landing gear needed for hypersonic / supersonic flight?

It's a different thought process - it may lead to the same design. But, as a thought experiment....

Let's start with the rocket - standard stuff with air start capability. There are some structural differences as it has to be held horizontally near the centre - rather than being vertical.

Then we attach wings (with fuel tanks) ramjets, and landing gear. And then we have the issue of dispensing with these. If we design this for Mach 2 separation at 20,000m, you might be dispensing a cradle, two wings, and two jet engines. This sort of design can't fly, but it could parachute land? Maybe it could even work as a powerchute.

Concorde for example had the engines and main landing gear attached to the wings - and a nice tubular shape down the middle. The tail fin function could be wing mounted or perhaps dispensed with using active controls.
Take this design, and then figure out how to lose the wing sections at Mach 2, air start a rocket engine, and recover the wing sections, preferably at your launch base.

 

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #96 on: 08/05/2014 09:11 pm »
I recently saw a picture of the SR-71 with the D-21 rocket powered drone on its back and though it's not the same it made me wonder if you could piggyback a launcher for small payloads to LEO on something like the proposed SR-72 hypersonic aircraft. Would there be any advantages to launching from a aircraft at Mach 6 flying at say something like 150,000 feet compared to a more conventional launch aircraft? Or would any advantages be offset by greater difficulties from using such a vehicle.

http://www.lockheedmartin.co.uk/us/news/features/2013/sr-72.html
AFAIk the D21 was never successfully launched from the SR71.

The SR72 is a powerpoint plane at this point.

This idea has been discussed at length.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #97 on: 08/05/2014 09:15 pm »

I recently saw a picture of the SR-71 with the D-21 rocket powered drone on its back and though it's not the same it made me wonder if you could piggyback a launcher for small payloads to LEO on something like the proposed SR-72 hypersonic aircraft. Would there be any advantages to launching from a aircraft at Mach 6 flying at say something like 150,000 feet compared to a more conventional launch aircraft? Or would any advantages be offset by greater difficulties from using such a vehicle.

http://www.lockheedmartin.co.uk/us/news/features/2013/sr-72.html
AFAIk the D21 was never successfully launched from the SR71.

The SR72 is a powerpoint plane at this point.

This idea has been discussed at length.

It's clear though see my post just above that LM are actively researching the topic, what that consists of your guess is as good as mine.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #98 on: 08/05/2014 11:02 pm »
New interview with Marilyn Hewson head of LM & spot how many times she mentions their investment in hypersonics, clue it's quite a few.

http://www.c4isrnet.com/article/20140805/C4ISRNET08/308050004/How-Lockheed-Martin-plans-compete-against-Google-Amazon
Read it. The answer is 1. on page 3.

"Hypersonics would be a great example. We have been investing in that for a number of years. "

Wasting people's time is not a good way to convince them you know what you're talking about or that it's worth them listening to you.

Your choice.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline DMeader

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #99 on: 08/05/2014 11:18 pm »
AFAIk the D21 was never successfully launched from the SR71.
TECHNICALLY correct as the launch aircraft was not the SR-71, but was actually a modified A-12. But...

Successful launches were in fact made. As project TAGBOARD, successful launches on
-5 March 1966
-27 April 1966
-16 June 1966

Now, overall MISSION success is another matter, but in these instances the LAUNCH itself was successful.

30 July 1966 attempt was the D-21 collision with the M-21 (modified A-12) immediately after launch. Pilot Bill Park and  Launch Control Officer Ray Torick ejected but Torick drowned after landing in the ocean.

After that, the D-21 was modified for launch from the B-52 as project SENIOR BOWL.
« Last Edit: 08/06/2014 04:12 pm by DMeader »

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #100 on: 08/06/2014 02:27 pm »
New interview with Marilyn Hewson head of LM & spot how many times she mentions their investment in hypersonics, clue it's quite a few.

http://www.c4isrnet.com/article/20140805/C4ISRNET08/308050004/How-Lockheed-Martin-plans-compete-against-Google-Amazon
Read it. The answer is 1. on page 3.

"Hypersonics would be a great example. We have been investing in that for a number of years. "

Wasting people's time is not a good way to convince them you know what you're talking about or that it's worth them listening to you.

Your choice.

Answers are always more effective if they are correct and look like the person has actually read the article properly. As well as page 3.

Taken from page 2 my bolding. This is the far more interesting quote of the two.

Quote
We are always integrating it into our current product lines to keep them relevant, and coming up with new capabilities -- whether directed energy or hypersonics or the advanced materials like nanotechnology or advanced manufacturing and 3-D printing. We are investing to stay current and bring to our customers that innovation that they look for in Lockheed Martin.
« Last Edit: 08/06/2014 02:41 pm by Star One »

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #101 on: 08/06/2014 06:53 pm »
Taken from page 2 my bolding. This is the far more interesting quote of the two.

Quote
We are always integrating it into our current product lines to keep them relevant, and coming up with new capabilities -- whether directed energy or hypersonics or the advanced materials like nanotechnology or advanced manufacturing and 3-D printing. We are investing to stay current and bring to our customers that innovation that they look for in Lockheed Martin.
So two mentions of hypersonics of one line each, in a 4 page report

I stand corrected.

MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #102 on: 08/06/2014 07:03 pm »
Taken from page 2 my bolding. This is the far more interesting quote of the two.

Quote
We are always integrating it into our current product lines to keep them relevant, and coming up with new capabilities -- whether directed energy or hypersonics or the advanced materials like nanotechnology or advanced manufacturing and 3-D printing. We are investing to stay current and bring to our customers that innovation that they look for in Lockheed Martin.
So two mentions of hypersonics of one line each, in a 4 page report

I stand corrected.

I concede that perhaps I should have empathised the content rather than number in this case.
« Last Edit: 08/06/2014 08:05 pm by Star One »

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #103 on: 08/07/2014 06:25 am »
I concede that perhaps I should have empathised the content rather than number in this case.
Thank you. The article was a fairly major disappointment.

I agree that LM has some interest in hypersonics and think they may have a plan to do it.

Time will tell if this actually goes anywhere and if so will it be the son-of-SR71 or NASP II (for those who've read Facing the Heat Barrier that would be NASP III).  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #104 on: 08/07/2014 04:03 pm »
I concede that perhaps I should have empathised the content rather than number in this case.
Thank you. The article was a fairly major disappointment.

I agree that LM has some interest in hypersonics and think they may have a plan to do it.

Time will tell if this actually goes anywhere and if so will it be the son-of-SR71 or NASP II (for those who've read Facing the Heat Barrier that would be NASP III).  :(

It also wasn't that different to an earlier interview I posted from her. I wonder why they feel the need to get it into their interviews if they are not really going to say anything much, other than thinking its good PR.

Be assured should I see another such interview unless it says something significantly different from these two I shall pass it by.
« Last Edit: 08/07/2014 04:05 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #105 on: 08/07/2014 09:03 pm »
Aaarrggh! You're building an engine around a duel-mode ramjet... Why again? Lets see if the ramjet kicks in around Mach-4 and its designed at ALL decently it should be then capable of flying to Mach-6 with ease. What's the airframes proposed top speed? Mach-6? Then why the HELL would you even consider putting in a SCramjet you don't even NEED?

What? Oh of course, silly me, everyone knows that a hypersonic aircraft has to use a SCramjet engine because ramjets can only go, you know supersonic and not hypersonic well duh...
I'd guess even a conservative approach of regular jet engines would get you to M2.2 or 2.4 and a ramjet to M3 would give you M5.4.

SERIOUSLY "conservative" given a subsonic combustion ramjet designed to have a maxium (sweetspot) speed with a fixed inlet and exhaust of Mach-4 ACCIDENTLY flew to Mach-5.5 (and was still accellerating) when it ran out of fuel with a stuck fuel-valve :)

Seriously, Glenn Olson of "alt-accel.com" noted that there was an abundance of cited work on subsonic ramjet engine operations at speeds up to @Mach-7 for it to be quite logical that engine had in fact been tested to those speeds. He also pointed out (and the owner/operator of "Ex-Rocketmans Take" blog who IS an actual ramjet engine engineer has confirmed) that when interviewing people who worked on and with subsonic ramjet engines none of them saw any major issues to running such engines to speeds in excess of Mach-8. While no one has ever gone "on-record" stating it people who were directly involved in the design, construction and testing of the BOMARC missile engines (Mardquart) to a one would make note that the AIRFRAME of the BOMARC would fall apart around Mach-10 but that the engines would still be working. (Producing no thrust I'm sure and melting in the process but working :) )

Quote
Which I'd call pretty good, but obviously for some people that's just not good enough.  :(

It comes down to what you intent to DO I suppose, the problem is that most people who are "supposedly" working  on "hypersonic-flight/propulsion" are really JUST working on SCramjets and to heck with any practical or operational considerations :(

Quote
When the history of high speed flight is written I think hypersonic flight --> hypersonic combustion will go down in history with cruise = launch as one of the the great conceptual mistakes in vehicle design.   :(

?? Just a note but HYPERSONIC combustion isn't on ANYONES radar or thought pattern! :) SUPERSONIC combustion has been tough enough I don't think anyone is thinking about making it 5-times hard than it already is :D

Seriously hypersonic flight which is technically any "flying" at speeds higher than Mach-5 is a "given" for any serious use of airbreathing AND "flying" on the way to orbit. The foremost example being the Skylon :)

An aerodynamic "lifting" trajectory pretty much demands getting to somewhere above Mach-5 before going for orbit where as "just" speaking of something like "launch-assist" anywhere between Mach-0.90 and Mach-5+ all "give" a viable boost to orbital launch. However I have to agree that the "conceptual" direction along with the insistance on SCramjets has been a major road-block on actually DEVELOPING anything for the last 40 years.

Quote
But of course that won't give you the dream of air breathing to orbit.  :(

THE problem is the folks who are actually getting money and work are NOT the ones who "dream" of air breathing to orbit despite what they say. Those that do are ignored because they don't propose the high-cost, high-profile technology but insist that we can do the job with what amounts to "off-the-shelf" parts and technology :(

Quote
But my instinct is that even if you manage to inject your fuel into the airflow with minimal turbulence and you use H2 you just won't inject enough heat to the flow to get enough acceleration before you run out of fuel.  :(

The problem is your "instinct" conflicts with the math and lab testing, it's been "bench" proven to around Mach-7 with hydrocarbon fuels and IIRC Mach-9 with hydrogen but there is a major disconnect between what seems to work in the lab and the same thing working in the "real-world" :)

Again the MATH and THEORY "prove" that using hydrogen you can get a SCramjet to air-breath past Mach-25 and still manage to get positve heat injection. (Going out a long way on a short limb of memory IIRC the supersonic flow of air at the speed of Mach-25 is less than the temperature reached by some of the Nuclear heating test elements for the very late NERVA program which is what pretty much proves the idea will "work" except for the whole disturbance during the fuel injection and no one getting a SCramjet to work at speeds as high as Mach-12+ let alone Mach-25... It's just "simple" engineering right? :) )

But in the end the "math-and-theory" ignore everything in front of and behind the combustion chamber of the SCramjet and simply "assume" that everything works to get to point-Z without "bothering" with points A-through-X... Refer back to it being "engineering" and not something to worry about...

The advocates make it SOUND so simple while PROMISING so much and waving that pretty-pretty math/theory will poo-pooing the people who try and point out the man behind the curtain, the curtain, the building and the city needed to support it all. And they make it SOUND so damn good no one who suggests doing it with what is available and practical are either ignored or worse for suggesting NOT going for the "best" solution. It just doesn't make any SENSE to me...

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #106 on: 08/07/2014 09:31 pm »
AFAIk the D21 was never successfully launched from the SR71.
TECHNICALLY correct as the launch aircraft was not the SR-71, but was actually a modified A-12. But...

Successful launches were in fact made. As project TAGBOARD, successful launches on
-5 March 1966
-27 April 1966
-16 June 1966

Now, overall MISSION success is another matter, but in these instances the LAUNCH itself was successful.

30 July 1966 attempt was the D-21 collision with the M-21 (modified A-12) immediately after launch. Pilot Bill Park and  Launch Control Officer Ray Torick ejected but Torick drowned after landing in the ocean.

After that, the D-21 was modified for launch from the B-52 as project SENIOR BOWL.

"Technically, technically" correct (we can do this all day long for a couple of years if you-all want :) ) the M-21 was not really a "modification" of the A-12 but a MODEL of the A-12 specifically built for the M-21/A-21 (TAGBOARD) missions. Similarly the SR-71 was in fact a MODEL varient of the A-12 which was an Interceptor aircraft (air-to-air attack FIGHTER aircraft) and the SECOND "version" where as the SR-71 was the FIRST design "base" for the entire series but the A-12 was actually finish designed and model built :)

ALL the "SR/A/M" airframes were basically the same with "modifications" per the specified mission. ALL of them had a "hard-point" mount on the back/top of the airframe (this was because at top-speed the AoA of the aircraft made that area more "benign" than the environment around the leading-edges/wings/engines) which could handle everything from the D-21 to a Nuclear Bomb. (The "S" is SR :) )

Somewhere (tm) I have a NASA report/study where they were looking at using the SR-71s to launch a large multi-propulsion type drone for studying hypersonic flight. They specifically addressed the M-21/D-21 accident and noted that while the majority of launches were successful the flights were not but this had nothing to do with the launch METHOD and even after TAGBOARD was transfered to B-52/C-130 (SENIOR BOWL) launches the autopilot of the D-21 was never gotten to the level of reliabilty needed for the safety of M-21. It was a known fault, and the fact that even when launched subsonic with rocket boost the autopilot was the part of the system that most often failed was never really resolved. (The accident, just to be clear was NOT caused by the drone "bouncing" off the supersonic shockwave but by the D-21 autopilot suddenly commanding the D-21 into a dive which caused it to collide with the M-21)

In another study I have (somewhere, tm :) ) where its proposed to take a "stock" D-21 and turn it into a hypersonic engine test bed the FIRST thing that is discussed is the REPLACEMENT of ALL the electronics for modern WORKING (and that's capitalized in the report in places as well :) ) flight controls :)

Randy
 
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #107 on: 08/07/2014 09:43 pm »
I concede that perhaps I should have empathised the content rather than number in this case.
Thank you. The article was a fairly major disappointment.

I agree that LM has some interest in hypersonics and think they may have a plan to do it.

Time will tell if this actually goes anywhere and if so will it be the son-of-SR71 or NASP II (for those who've read Facing the Heat Barrier that would be NASP III).  :(

Correction that would "Aerospaceplane MkIII" actually :)

I wonder why they feel the need to get it into their interviews if they are not really going to say anything much, other than thinking its good PR.

Got it in one actually :) If you recall the stuff published about Boeings "Launcher-One" you'll see the exact same thing in it. It all revolves around there being an official interest in "hypersonics" so to be as "relevent" as possible general mention of the keywords "hypersonics," "SCramjets," "zero-to-fill-in-the-blank-speeds," and (usually) "cheap-space-launch" and/or "two-hours-from-California-to-Australia/Japan/Korea" must be included even though the actual PRODUCT/TECHNOLOGY/PROCESS may have little or nothing to do with any of the above is required.

And it's not just limited to folks like LM or Boeing either. I have seen a magazine ad which followed a total "fluff" article about Boeings "hypersonic engine support program" (how many hypersonic engines DOES Boeing in fact build? :) ) which showed an obviously "hypersonic" cargo aircraft sitting on an airport terminal tarmac (obviously a modified picture from one of the "Fast Forward" studies but I'm not sure which one) being loaded and unloaded with cargo and passngers. What was the ad for? Septic servicing company... :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline DMeader

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #108 on: 08/07/2014 11:52 pm »
"Technically, technically" correct (we can do this all day long for a couple of years if you-all want :) )

If you wish to argue with my terminology and sources, (Mssrs. Miller and Jenkins et al) and split finer and finer hairs, you're certainly welcome to.


Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #109 on: 08/08/2014 08:52 pm »
"Technically, technically" correct (we can do this all day long for a couple of years if you-all want :) )

If you wish to argue with my terminology and sources, (Mssrs. Miller and Jenkins et al) and split finer and finer hairs, you're certainly welcome to.

Not at all and not "arguing" really just pointing out finer detail because lets face it everyone loves the SR-71 right :)

As an aside but in the general direction of the thread, at one point it was "suggested" that the M-21 could be replaced with a varient of the B-58 then being retired as the D-21 and a smaller booster rocket could be used in place of the usually carried pod. "Suggested" was as far as it ever got (a memo IIRC) because it was pointed out that unlike the aft-upper-side environment of the M-21 the under-side-center-line set up would not allow the D-21 ramjet to start properly. It was also pointed out that the B-58 was being retired due to wing-box cracking so most aircraft were going to be no longer operational anyway.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #110 on: 08/09/2014 07:49 am »
SERIOUSLY "conservative" given a subsonic combustion ramjet designed to have a maxium (sweetspot) speed with a fixed inlet and exhaust of Mach-4 ACCIDENTLY flew to Mach-5.5 (and was still accellerating) when it ran out of fuel with a stuck fuel-valve :)

Seriously, Glenn Olson of "alt-accel.com" noted that there was an abundance of cited work on subsonic ramjet engine operations at speeds up to @Mach-7 for it to be quite logical that engine had in fact been tested to those speeds. He also pointed out (and the owner/operator of "Ex-Rocketmans Take" blog who IS an actual ramjet engine engineer has confirmed) that when interviewing people who worked on and with subsonic ramjet engines none of them saw any major issues to running such engines to speeds in excess of Mach-8. While no one has ever gone "on-record" stating it people who were directly involved in the design, construction and testing of the BOMARC missile engines (Mardquart) to a one would make note that the AIRFRAME of the BOMARC would fall apart around Mach-10 but that the engines would still be working. (Producing no thrust I'm sure and melting in the process but working :) )
Actually alt-accel.com was where I got the M3 range limit.  :) I guess I'm still thinking of the jet assist stage idea of keeping things, as far as possible, well within the routine experience base. I tend to feel that once a vehicle is flying (and preferably earning revenue) then you can widen the envelope if the airframe has been designed to accommodate the necessary increased flight range and is fully reusable.  :(

Obviously every 100 m/s that you can stay air breathing means either a lower 2nd stage propellant load or a higher payload, provided the aerodynamics are up to it.  Sticking 3 Mach numbers on the 1st stage operating range will need considerable planning in the airframe design.

Quote
It comes down to what you intent to DO I suppose, the problem is that most people who are "supposedly" working  on "hypersonic-flight/propulsion" are really JUST working on SCramjets and to heck with any practical or operational considerations :(
I'd call that a "technology push" rather than an "application pull." So far it's looked like a job for life.  :(

Quote
?? Just a note but HYPERSONIC combustion isn't on ANYONES radar or thought pattern! :) SUPERSONIC combustion has been tough enough I don't think anyone is thinking about making it 5-times hard than it already is :D
Oops.  :( I did look up "flame speed" and for some reason I thought it was in the 1000s of m/s not the 10s.  I wonder if things would be easier if you could trigger one of those deflagration to detonation transitions...
Technically PDE's do do hypersonic combustion as the detonation wave velocity is in the M5+ range.

I still find it pretty amazing that technology (despite it's much shorter maturation period) has reached flight test with a crewed vehicle.
Quote
Seriously hypersonic flight which is technically any "flying" at speeds higher than Mach-5 is a "given" for any serious use of airbreathing AND "flying" on the way to orbit. The foremost example being the Skylon :)

An aerodynamic "lifting" trajectory pretty much demands getting to somewhere above Mach-5 before going for orbit where as "just" speaking of something like "launch-assist" anywhere between Mach-0.90 and Mach-5+ all "give" a viable boost to orbital launch. However I have to agree that the "conceptual" direction along with the insistance on SCramjets has been a major road-block on actually DEVELOPING anything for the last 40 years.
That insistence that only supersonic combustion can do it looks like the biggest block to progress.  :(
Quote
THE problem is the folks who are actually getting money and work are NOT the ones who "dream" of air breathing to orbit despite what they say. Those that do are ignored because they don't propose the high-cost, high-profile technology but insist that we can do the job with what amounts to "off-the-shelf" parts and technology :(
It certainly looks that way. The amazing results (for the budget) of the DC-X programme were at least as much due to SDIO have a need and frankly not really caring how it got done. I think the DARPA XS-1 programme might be the closest equivalent stimulant. Possibly nto too surprising given the they are run by the same guy.  Although wheather any entrant will have wings is another matter  :( .

Quote
The problem is your "instinct" conflicts with the math and lab testing, it's been "bench" proven to around Mach-7 with hydrocarbon fuels and IIRC Mach-9 with hydrogen but there is a major disconnect between what seems to work in the lab and the same thing working in the "real-world" :)
The perils of being an armchair engineer.  :(

I'd be less convinced by the maths as it would all depend on the what assumptions and simplifications were made to get an answer. OTOH actual bench firing is another matter.
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Again the MATH and THEORY "prove" that using hydrogen you can get a SCramjet to air-breath past Mach-25 and still manage to get positve heat injection. (Going out a long way on a short limb of memory IIRC the supersonic flow of air at the speed of Mach-25 is less than the temperature reached by some of the Nuclear heating test elements for the very late NERVA program which is what pretty much proves the idea will "work" except for the whole disturbance during the fuel injection and no one getting a SCramjet to work at speeds as high as Mach-12+ let alone Mach-25... It's just "simple" engineering right? :) )
That's an interesting data point but I would note a) There is no air intake so no air intake drag losses to overcome AFAIK the only exception to that was the reactor on the Pluto nuclear ramjet b)The heat was not provided by combustion but conduction from hot objects. From memory actual dissocation only starts around 4-5000c.
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But in the end the "math-and-theory" ignore everything in front of and behind the combustion chamber of the SCramjet and simply "assume" that everything works to get to point-Z without "bothering" with points A-through-X... Refer back to it being "engineering" and not something to worry about...
Once someone say the engine has to be tightly integrated into the airframe design I'd guess everything from the nose of the vehicle backwards has to be considered and traded for overall best efficiency.
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The advocates make it SOUND so simple while PROMISING so much and waving that pretty-pretty math/theory will poo-pooing the people who try and point out the man behind the curtain, the curtain, the building and the city needed to support it all. And they make it SOUND so damn good no one who suggests doing it with what is available and practical are either ignored or worse for suggesting NOT going for the "best" solution. It just doesn't make any SENSE to me...
Bill Gunston commented of AA Griffith (Rolls Royce engine designer and something of a rival to Frank Whittle) that he was able to convince people his designs could work because he had such a good illustrator/draughtsman.

IRL they proved complex and not as efficient as they looked on paper (when they got built).

I see something of a similar effect effect with hypersonics.

Personally I think the problems of building an airframe to cruise at M5+ (Basically all the aerodynamic problems of the SR71 and Concorde and then some) should be sufficent challenge while trying to keep the engines as mainstream as possible.

Which reminds me IIRC the engines on the XB70 were not particularly exotic, although pretty big. Once compression lift was discovered no one seemed to doubt it could fly the mission without any kind of special fuel or ramjet nacelle design.
« Last Edit: 08/09/2014 07:50 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #111 on: 08/09/2014 08:19 am »

<brief history of A12/SR71/D21 programme snipped>
Having read into the history I'd always thought the A12 came first (for the CIA) and then transitioned into the SR71 for the USAF. I was aware that their were plans for versions to carry AAM's (including nuclear warheads) and KE penetrators to hit very hard targets but I did not realize all  of them had that dorsal hard point (I though it was a special mod for the D21 carriage).
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Somewhere (tm) I have a NASA report/study where they were looking at using the SR-71s to launch a large multi-propulsion type drone for studying hypersonic flight. They specifically addressed the M-21/D-21 accident and noted that while the majority of launches were successful the flights were not but this had nothing to do with the launch METHOD and even after TAGBOARD was transfered to B-52/C-130 (SENIOR BOWL) launches the autopilot of the D-21 was never gotten to the level of reliabilty needed for the safety of M-21. It was a known fault, and the fact that even when launched subsonic with rocket boost the autopilot was the part of the system that most often failed was never really resolved. (The accident, just to be clear was NOT caused by the drone "bouncing" off the supersonic shockwave but by the D-21 autopilot suddenly commanding the D-21 into a dive which caused it to collide with the M-21)

In another study I have (somewhere, tm :) ) where its proposed to take a "stock" D-21 and turn it into a hypersonic engine test bed the FIRST thing that is discussed is the REPLACEMENT of ALL the electronics for modern WORKING (and that's capitalized in the report in places as well :) ) flight controls :)
I found quite a good web page on the Tagboard programme. Lockheed engineers found the autopilot used a bunch of relays which were not really up to the job.  :(
I though it was here  www.wvi.com/ based on the page background but I can't find the exact page in the site.

The page had excerpts from Kelly Johnson's project log in which he reported meetings with Honeywell staff who also had trouble with the astro nav system.

Frankly the whole auto pilot/nav package seems a bit of a lemon (although for 1cu ft in the early 60's it was probably pretty impressive).  It also used the "stacked cordwood" method of direct spot welding parts together without PCBs, which made repairs a royal PITA. :(

BTW There are still a bunch of these mothballed  in the aircraft storage area out in the desert.

And a note on my terminology

For people unaware of the original Aerospace Plane of the early 60's this latest proposal could be seen as "NASP II" but in reality it is NASP III, although I'm presuming LM want it to turn out more like the original SR71 programme.

Time will tell if either of these visions comes true.  :(
« Last Edit: 08/09/2014 08:24 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #112 on: 08/09/2014 09:24 am »
"Technically, technically" correct (we can do this all day long for a couple of years if you-all want :) )

If you wish to argue with my terminology and sources, (Mssrs. Miller and Jenkins et al) and split finer and finer hairs, you're certainly welcome to.

Not at all and not "arguing" really just pointing out finer detail because lets face it everyone loves the SR-71 right :)

As an aside but in the general direction of the thread, at one point it was "suggested" that the M-21 could be replaced with a varient of the B-58 then being retired as the D-21 and a smaller booster rocket could be used in place of the usually carried pod. "Suggested" was as far as it ever got (a memo IIRC) because it was pointed out that unlike the aft-upper-side environment of the M-21 the under-side-center-line set up would not allow the D-21 ramjet to start properly. It was also pointed out that the B-58 was being retired due to wing-box cracking so most aircraft were going to be no longer operational anyway.

Randy

It's my belief that one of the reasons that there is so much interest out there in hypersonic flight (or I should say aircraft that fly exceptionally fast) amongst the general public is the high regard the SR-71 is held in. Look at the fuss that brewed up when the SR-72 concept was announced.

It's also why I believe there is a constant belief in certain quarters that a replacement for the SR-71 must either be in use or at hand and why something like the urban legend of the Aurora gained so much traction online and has hung around so long.
« Last Edit: 08/09/2014 02:51 pm by Star One »

Offline aero

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #113 on: 08/10/2014 05:39 am »
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It's also why I believe there is a constant belief in certain quarters that a replacement for the SR-71 must either be in use or at hand and why something like the urban legend of the Aurora gained so much traction online and has hung around so long.

Maybe it was just because of the sightings and pictures? I found this photo on the Internet some a few months ago. It caught my interest because it was labeled "Aurora 'something ... something' SR-71." See the attachment. I did not change the file name, maybe the original can be located.
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Offline hop

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #114 on: 08/10/2014 06:09 am »
I found this photo on the Internet some a few months ago.
Bad photoshop. You can find the original sr71 pic at
http://www.dfrc.nasa.gov/Gallery/Photo/F-16XL1/HTML/EC95-43024-2.html

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #115 on: 09/02/2014 07:01 pm »
Which reminds me IIRC the engines on the XB70 were not particularly exotic, although pretty big. Once compression lift was discovered no one seemed to doubt it could fly the mission without any kind of special fuel or ramjet nacelle design.

Well yes BUT the "engines" for that big bird WERE pretty much the entire back-two-thirds of the vehicle we will recall :) Worked well up to a little over Mach-3 (supposedly) and with a different set of intakes and vehicle design...

There was some speculation at one point of having the engines moved forward a bit and trying to build J58 like "turbo-ramjets" into an advanced design but the cost and issues with the B70 itself kind of did that one in really quick.
Having read into the history I'd always thought the A12 came first (for the CIA) and then transitioned into the SR71 for the USAF. I was aware that their were plans for versions to carry AAM's (including nuclear warheads) and KE penetrators to hit very hard targets but I did not realize all  of them had that dorsal hard point (I though it was a special mod for the D21 carriage).

No though I was surpised to find it out myself that it was an "original" inclusion. Kind of makes some sense I suppose if you're at the point where you're fitting everything down to "interceptors" with free-fall nuclear weapons which was a Cold War specialty (and requirement) for most tactical as well as stratigic aircraft :)
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Frankly the whole auto pilot/nav package seems a bit of a lemon (although for 1cu ft in the early 60's it was probably pretty impressive).  It also used the "stacked cordwood" method of direct spot welding parts together without PCBs, which made repairs a royal PITA. :(

BTW There are still a bunch of these mothballed  in the aircraft storage area out in the desert.

Which is why some people would love to see them "repurposed" in the first place :)

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And a note on my terminology

For people unaware of the original Aerospace Plane of the early 60's this latest proposal could be seen as "NASP II" but in reality it is NASP III, although I'm presuming LM want it to turn out more like the original SR71 programme.

Time will tell if either of these visions comes true.  :(

Thanks I keep forgetting how much we "assume" is known around here :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #116 on: 09/02/2014 07:18 pm »
It's my belief that one of the reasons that there is so much interest out there in hypersonic flight (or I should say aircraft that fly exceptionally fast) amongst the general public is the high regard the SR-71 is held in. Look at the fuss that brewed up when the SR-72 concept was announced.

"Fuss" would be correct as it stirred up FAR more official dis-interest (as it "we ain't gonna fund no such thing") from Congress than public interest which amounted to "Neat..." and not much else. (Stirred a LOT of interest in the industrial aerospace circles as everyone lined up to try and get contracts but the lack of interest killed that...

A lot of folks get "interested" in hypersonic right up to the point where the reality gets talked about and the fact is outside of a VERY narrow range of uses its worse economically (especially for cruise purposes which is the majority of the "talk" in the first place) than supersonic is and twice as hard to reach and sustain.
But everyone who "talks" hypersonics tries over and over again to tie it into a solid "commercial" case which inevitably leads them to try and include "hypersonic passenger service" and "airbreathing orbital space launch" into the mix JUST to make the case seem more "rational" than it really is.

It doesn't help that the majority of the folks doing the talking have little or no idea as to WHY supersonic travel wasn't and isn't the massive business that it was always assumed to be.
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It's also why I believe there is a constant belief in certain quarters that a replacement for the SR-71 must either be in use or at hand and why something like the urban legend of the Aurora gained so much traction online and has hung around so long.

There's also the fact that people WANT there to be things they don't officially "know" about they can find out about because the "thrill" of being in the know is so great. And there's a whole segment of folks who cater to that audience as shown by the above photo-shop picture :) People are pretty much "bored" with reality and even the idea of there being "something" more is enough to get people excited about the prospect even if 2 people have 6 different "ideas" on where that comes from or leads :)

The problem is despite what the military "says" they might need an SR-71 replacement for they really can't justify or support a manned, hypersonic platform to do it with. And I seriously doubt they could keep it a secret as long as "Aurora" has supposedly been in the works.
I love to point out to folks who think its possible that the only way an "Aurora" like aircraft could be built and tested was that it was ONLY built and tested... If it ever became operational it couldn't remain "black" we just don't have the ability to do that with an operational system.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline sghill

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #117 on: 09/02/2014 07:33 pm »
I like the concept of a hypersonic aircraft for LEO launcher on paper, but I've never seen any accounting math which tells me it'd be worth it.

The difference in starting airspeed per dollar spent on development and operations for the a rocket which launches from a hypersonic carrier aircraft versus a larger rocket which launches from a subsonic carrier aircraft is the relevant cost delta.  Everything else is an ignored cost.

In other words, for the exact same payload to orbit, is it cheaper to slap on a bigger solid motor and develop a larger subsonic carrier aircraft than it is to develop a hypersonic aircraft that air launches a smaller rocket.

So far, the answer appears to be that it's cheaper to use a slower, but larger aircraft to carry a larger rocket than it is to develop a faster aircraft with a smaller rocket.  I'd postulate that with solid propellants, it's vastly cheaper.  The Pegasus booster and the Strato-Launch concepts are betting their business models on it.  Nothing's ever been built using the hypersonic carrier business model, so perhaps it's just vaporware as far as the business model is concerned.

Now, in terms of non-economic considerations, such as military applications, there may be some valid mission-oriented rationale for developing that hypersonic carrier aircraft, but honestly, I can't think of any missions where the immediate need to orbit a spacecraft (versus blowing one up) is so great that it couldn't wait a few more minutes to be launched from a sub-sonic aircraft or surface-launched booster.
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Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #118 on: 09/02/2014 07:43 pm »
A very recent example of how over-excited people get about hypersonic and related projects, see the article below. You have to kind admire all the old aviation projects dragged up in it including the XB-70 mentioned up thread.

http://foxtrotalpha.jalopnik.com/new-panoramic-images-show-area-51-s-new-mystery-hanger-1628823466

Strangely no mention of the two most likely opinions that it is another scoot and hide shelter or it's for the Speed Agile project but I suppose they are both too boring to mention.
« Last Edit: 09/02/2014 07:50 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #119 on: 09/02/2014 07:54 pm »
A very recent example of how over-excited people get about hypersonic and related projects, see the article below. You have to kind admire all the old aviation projects dragged up in it including the XB-70 mentioned up thread.

http://foxtrotalpha.jalopnik.com/new-panoramic-images-show-area-51-s-new-mystery-hanger-1628823466

Strangely no mention of the two most likely opinions that it is another scoot and hide shelter or it's for the Speed Agile project but I suppose they are both too boring to mention.

There's a probably even more "mundane" answer that no one is interested in looking at :)

Storage space. There's some stuff that's been experimented on and with that we simply don't want anyone to know about for lack of wanting to explain how or where we got it from. (Like third-country vehicles that neither we nor the nation that bought them want to tell the Russians we have, though mention that on most "forums" and everyone thinks "Alien saucers" :) ) As well as vehicles we don't want to destroy (or bury) that can give an enemy a lot of information on the direction of research taken by its shape, size and or other mold line factors :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #120 on: 09/02/2014 08:46 pm »
I like the concept of a hypersonic aircraft for LEO launcher on paper, but I've never seen any accounting math which tells me it'd be worth it.

What you dare DOUBT the experts on SCramjets changing the world? :)

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The difference in starting airspeed per dollar spent on development and operations for the a rocket which launches from a hypersonic carrier aircraft versus a larger rocket which launches from a subsonic carrier aircraft is the relevant cost delta. Everything else is an ignored cost.

Heck supersonic has yet to be "shown" a cost effective launch concept let alone hypersonic! But the 'numbers' look good when you run them without the costs of building a whole new airplane :)

The other relevent delta is of course the cost of the supersonic/hypersonic platform versus that of the subsonic platform which is usually quite a bit higher for the former, especially if an already existing platform can be found to provid the latter :)

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In other words, for the exact same payload to orbit, is it cheaper to slap on a bigger solid motor and develop a larger subsonic carrier aircraft than it is to develop a hypersonic aircraft that air launches a smaller rocket.

Actually NOT so straight forward as it might sound/look either. Part of the problem is the idea that a supersonic/hypersonic launch platform will always carry a "smaller" LV than a subsonic carrier aircraft. Which IS true as far as it goes, but it leaves a lot of room for discussion since the smaller vehicle launched at higher speeds tends to have a higher payload to orbit with all things being equal after the launch. The large subsonic platform has be be VERY much larger in order to get around the speed differential. And/or use techniques capable of placing the payload at launch on at least one other "axis" of the important factors of Air Launch:
1) Speed
2) AoA
3) Altitude.

Since by its nature subsonic launch ignores the first factor it has to do something to "make-up" for that lack with the other two factors. So far the only people that have bothered to address this is AirLaunch with the TLAD system.

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So far, the answer appears to be that it's cheaper to use a slower, but larger aircraft to carry a larger rocket than it is to develop a faster aircraft with a smaller rocket. I'd postulate that with solid propellants, it's vastly cheaper. The Pegasus booster and the Strato-Launch concepts are betting their business models on it.  Nothing's ever been built using the hypersonic carrier business model, so perhaps it's just vaporware as far as the business model is concerned.

Actually both Pegasus and StratoLaunch are betting the business on a pretty shakey case. Especially when using solids because their performance is seriously sub-optimal in the job. Liquid boosters would be a huge improvement even though they would take additional structural bracing and support to accomplish. Both Pegasus and StratoLaunch are taking already marginal systems (solid boosters) and forcing them to do all the "work" except hauling themselves to a piddling launch altitude of around 40,000ft. In both cases the only "advantage" here is that the solid motors are more robust structurally and can stand the required 'pull-up' manuever without too much additional structure dedicated to aerodynamic lift and manuver.

Adapt a TLAD or similar system and the rockets could be much higher performance liquids with about the same effort and have a higher payload to orbit for it.

Quote
Now, in terms of non-economic considerations, such as military applications, there may be some valid mission-oriented rationale for developing that hypersonic carrier aircraft, but honestly, I can't think of any missions where the immediate need to orbit a spacecraft (versus blowing one up) is so great that it couldn't wait a few more minutes to be launched from a sub-sonic aircraft or surface-launched booster.

One thing to keep in mind is turn-around time and the ability to launch multiple times a day is a given with a aircraft "booster" unlike any "standard" launch system. The aircraft is well known pacing item and everything else hinges on having enough rockets to fly :)

Now here I'm going to point out that you really do NOT need an "aircraft" in the first place, especially a manned one that seems to be the baseline concept when anyone approaches the idea of air-launch. Glenn Olson showed quite clearly that you can drop all the "extra" parts of an air launch system and launch a Pegasus using a half-dozen surplus military jet engines and simplified platform and reach the same payload goals that the Pegasus XL had with the basic Pegasus itself. And that's launching at only Mach-2 and 80,000ft without any special efforts which we should be well aware of are available. (Mach-4+ at 100,000ft with MIPCC is pretty easy actually given known technology)

You are somewhat size limited by the available engines and technology but if you can fly often enough....

Similarly, (I will point out that I'm SPECULATING here :) ) I've noted before that the StratoLaunch Carrier Aircraft is a very good match for a proposed "VLA" launch assist platform suggested by James Dewar in his book "The Nuclear Rocket" for carrying and launching an "assisted" nuclear SSTO vehicle with a significant payload to LEO all by itself.

The main problem I keep seeing is that folks are looking at either specific larger payloads (Falcon-9 or Falcon-Heavy) or they are looking at "aircraft-like" operations specifically requiring an "aircraft" in the mix to meet the supposed operations goals. What we want is the usabilty and operability of jet engines coupled with a rocket system matched to the potential given. That turns out to be a lot different than the direction every seems to be looking.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Stellar_Speedster

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #121 on: 11/18/2014 05:33 pm »
How about this one on rails in a mountainside delivered to the stratosphere with a steam capapult...and then ignited !

http://www.google.com/patents/US4802639

 ;)

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Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #123 on: 11/19/2014 05:57 pm »
Reheated here; http://robotpig.net/__aerospace/tsto.php?page=1

 :o

That's supersonic actually :) It doesn't get past Mach-4 with the carrier aircraft and "hypersonic" is above Mach-5 just FYI ;) The patent you post is for this same system btw. In reality if you use a 'steam-catapult' or rail system you would probably lose the jet engines as they are fulfilling the same role of getting the vehicle into the stratosphere. But you also lose a great deal of fleixabilty in trajectory by limiting yourself to a single launch point.

This is probably one of the better air-breathing launch vehicle designs out there IF you insist on having a full-up carrier vehicle for what amounts to an "assisted" Single Stage To Orbit orbital vehicle. It's based on initial work done under the BETA and BETA-II concept study:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920002777.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920012293.pdf

Which WAS a hypersonic design but found to be much more costly to build than initially thought mostly BECAUSE it was a hypersonic design :)

Personally I think you could about half the vehicle(s) sizes if you went with methalox rather than hydrolox which would reduce your construction costs by a lot. Even better was the SpaceJet Concept:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810020560.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790015826.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780003229.pdf
http://crgis.ndc.nasa.gov/historic/File:L-79-965.jpg
http://www.secretprojects.co.uk/forum/index.php?topic=11026.0
http://www.up-ship.com/eAPR/images/art33ani.jpg

Which reduced the "carrier-aircraft" to flyback engine pods... Or you COULD simply go with JUST jet-engine pods launch assist... But that's a different thread :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Stellar_Speedster

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #124 on: 11/19/2014 07:51 pm »
Reheated here; http://robotpig.net/__aerospace/tsto.php?page=1

 :o

That's supersonic actually :) It doesn't get past Mach-4 with the carrier aircraft and "hypersonic" is above Mach-5 just FYI ;) The patent you post is for this same system btw. In reality if you use a 'steam-catapult' or rail system you would probably lose the jet engines as they are fulfilling the same role of getting the vehicle into the stratosphere. But you also lose a great deal of fleixabilty in trajectory by limiting yourself to a single launch point.

This is probably one of the better air-breathing launch vehicle designs out there IF you insist on having a full-up carrier vehicle for what amounts to an "assisted" Single Stage To Orbit orbital vehicle. It's based on initial work done under the BETA and BETA-II concept study:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920002777.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920012293.pdf

Which WAS a hypersonic design but found to be much more costly to build than initially thought mostly BECAUSE it was a hypersonic design :)

Personally I think you could about half the vehicle(s) sizes if you went with methalox rather than hydrolox which would reduce your construction costs by a lot. Even better was the SpaceJet Concept:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810020560.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790015826.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780003229.pdf
http://crgis.ndc.nasa.gov/historic/File:L-79-965.jpg
http://www.secretprojects.co.uk/forum/index.php?topic=11026.0
http://www.up-ship.com/eAPR/images/art33ani.jpg

Which reduced the "carrier-aircraft" to flyback engine pods... Or you COULD simply go with JUST jet-engine pods launch assist... But that's a different thread :)

Randy

Yes Randy interesting reading !


I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.

That might need another thread.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #125 on: 11/19/2014 08:08 pm »
Yes Randy interesting reading !

I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.

That might need another thread.

Look it up before you do though, I REALLY think "rail-launch-up-a-mountain-side" has been done before... A LOT :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline JasonAW3

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #126 on: 11/19/2014 08:29 pm »
Yes Randy interesting reading !

I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.

That might need another thread.

Look it up before you do though, I REALLY think "rail-launch-up-a-mountain-side" has been done before... A LOT :)

Randy

Randy,

     Were they using lubbed rails or Magnetic Levitation track?  I can see only getting to Mach 1.5 on Lubbed rails  But mag levs ought to get phenominal velocity going up a mountain.
My God!  It's full of universes!

Offline kch

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #127 on: 11/19/2014 08:36 pm »
Yes Randy interesting reading !

I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.

That might need another thread.

Look it up before you do though, I REALLY think "rail-launch-up-a-mountain-side" has been done before... A LOT :)

Randy

Randy,

     Were they using lubbed rails or Magnetic Levitation track?  I can see only getting to Mach 1.5 on Lubbed rails  But mag levs ought to get phenominal velocity going up a mountain.

Depends on what kind of lub you're using, as well as how much -- Mach 1.5 is gonna take "a whole lotta lub" (apologies to Zep fans) ... ;)

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #128 on: 11/19/2014 08:51 pm »
Yes Randy interesting reading !

I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.

That might need another thread.

Look it up before you do though, I REALLY think "rail-launch-up-a-mountain-side" has been done before... A LOT :)

Randy,

     Were they using lubbed rails or Magnetic Levitation track?  I can see only getting to Mach 1.5 on Lubbed rails  But mag levs ought to get phenominal velocity going up a mountain.

IIRC the answer is "yes" to all the above, at one point or another :) If you include the variations on having an semi-or fully evacuated tunnel which the rail runs in then you can in fact get up to speeds in excess of Mach-6 or better using "mag-lev" rails but having to count on "quick-acting" doors before your vehicle rams head-first into them... Well...

I think my favorite was the idea of using a large "half-pipe" track and an air-cushioned vehicle "sled" with propellant tanks that fed the rockets on the vehicle. IIRC the LV pulled up and away around Mach-4 and the sled continued around the top of the mountain and then back to the launch site.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #129 on: 11/19/2014 11:21 pm »
I seem to recall a documentary  about a rocket sled run at IIRC Los Alamos. The rig ran (at Sea Level) up to somewhere around M4-M6, although I think they were running it through a Helium filled tunnel (like a large garden cloche) to change the speed of sound.

The capabilities of leading edge systems built for special purpose can far outstrip the level of standard systems (although the price is likely to be pretty steep).
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Stellar_Speedster

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #130 on: 11/20/2014 08:22 am »
I seem to recall a documentary  about a rocket sled run at IIRC Los Alamos. The rig ran (at Sea Level) up to somewhere around M4-M6, although I think they were running it through a Helium filled tunnel (like a large garden cloche) to change the speed of sound.

The capabilities of leading edge systems built for special purpose can far outstrip the level of standard systems (although the price is likely to be pretty steep).

How fast is the speed of sound in Helium ?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #131 on: 11/20/2014 03:29 pm »
I seem to recall a documentary  about a rocket sled run at IIRC Los Alamos. The rig ran (at Sea Level) up to somewhere around M4-M6, although I think they were running it through a Helium filled tunnel (like a large garden cloche) to change the speed of sound.

The capabilities of leading edge systems built for special purpose can far outstrip the level of standard systems (although the price is likely to be pretty steep).

"Leading edge" is usually synonymous with "really expensive" anyway :)

If you google "light-gas-guns" you can see speeds averaging in the hypersonic, (shades of the topic! :) for many proposed and/or scale tested systems. Specifically using hydrogen or helium as a medium. (To be even more confusing due the higher "speed-of-sound" in those mediums you need to pay careful attention to the "results" given as some seem to switch back and forth between 'mach' numbers achieved being related to "speed-of-sound" in the air and that achieved within the medium. I was totally confused about one report that crowed over speeds achieved being something like "Mach-2.5" until it later noted this "translated" to something like Mach-8. As I recall the remark about the "projectile failing structurally soon after encountering atmospheric average air density" still brings a smile to my face. Who says scientist don't have a sense of humor? :) )

Your main issue is you still need a lot of infrastructure for the 'boost' you get and it doesn't "pay" without huge amounts of mass being moved on a regular basis.

How fast is the speed of sound in Helium ?

http://en.wikipedia.org/wiki/Speed_of_sound
@927m/s (@2074mph) from Yahoo answers :) (Compared to 343m/s or 767mph for air)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline cordwainer

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #132 on: 11/24/2014 07:35 am »
I suppose developing a "scram cannon" might have its uses. Make it large enough and you could use it to not only launch hypersonic drones or missiles but you might even use it to launch "tiny pebbles" like kinetic penetrators for taking out satellites.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #133 on: 12/18/2014 03:34 pm »
New article from Flight Global.

NASA launches study for Skunk Works SR-72 concept.

Quote
NASA has awarded a contract to Lockheed Martin to study the feasibility of building a hypersonic propulsion system for a concept intelligence, surveillance and reconnaissance (ISR) aircraft dubbed the SR-72 using existing turbine engine technologies.

The $892,292 contract “provides for a parametric design study to establish the viability of a turbine-based combined cycle (TBCC) propulsion system consisting of integrating several combinations of near-term turbine engine solutions and a very low Mach ignition Dual Mode RamJet (DMRJ) in the SR-72 vehicle concept,” the award document says.

If the study is successful, NASA wants to fund a demonstration programme. Lockheed would test the dual-mode ramjet in a flight research vehicle, and try to find solutions to issues like engine packaging and designing the thermal management system, Bartolotta says.

“We’re doing this at a lower Mach number so we need to figure out what are the issues for cocooning the turbine, what do we need to do to reignite that turbine once we come down from hypersonic speeds,” Bartolotta says.

http://www.flightglobal.com/news/articles/nasa-launches-study-for-skunk-works-sr-72-concept-407222/

And I presume linked to the above is this recent Reuters article.

Quote
Over the past year Skunk Works has invited a few journalists to its most secure facilities, including Palmdale, a site in the high desert 60 miles (100 km) from Los Angeles, where new products range from next-generation unmanned systems to a hypersonic aircraft twice as fast as its Blackbird SR-71 spy plane that could fly across country in just over an hour.

http://in.mobile.reuters.com/article/idINL1N0TS1CH20141210?irpc=932
« Last Edit: 12/18/2014 03:42 pm by Star One »

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #134 on: 12/19/2014 01:31 pm »
In operation, how long would Skylon spend between Mach 3 and 5.5 when it enters rocket mode?

Checking the Skylon C1 trajectory spreadsheet it hits M3 at 330secs in and ends air breathing at 694 secs, roughly 6 minutes.

We know the D2 configuration will be better, but we do not know how much better.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline sghill

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #135 on: 12/19/2014 03:19 pm »
New article from Flight Global.

NASA launches study for Skunk Works SR-72 concept.

Quote
NASA has awarded a contract to Lockheed Martin to study the feasibility of building a hypersonic propulsion system for a concept intelligence, surveillance and reconnaissance (ISR) aircraft dubbed the SR-72 using existing turbine engine technologies.

http://www.flightglobal.com/news/articles/nasa-launches-study-for-skunk-works-sr-72-concept-407222/

I'm dubious (to be polite) that NASA would award a contract for this purpose.  This is Air Force territory, not civilian aerospace.

More likely is the article got it wrong, and the contract is simply for further development of a supersonic civilian concept.

You only need speed if you aren't supposed to be over the particular patch of territory you are trying to image....
Bring the thunder!

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #136 on: 12/19/2014 03:50 pm »
New article from Flight Global.

NASA launches study for Skunk Works SR-72 concept.

Quote
NASA has awarded a contract to Lockheed Martin to study the feasibility of building a hypersonic propulsion system for a concept intelligence, surveillance and reconnaissance (ISR) aircraft dubbed the SR-72 using existing turbine engine technologies.

http://www.flightglobal.com/news/articles/nasa-launches-study-for-skunk-works-sr-72-concept-407222/

I'm dubious (to be polite) that NASA would award a contract for this purpose.  This is Air Force territory, not civilian aerospace.

More likely is the article got it wrong, and the contract is simply for further development of a supersonic civilian concept.

You only need speed if you aren't supposed to be over the particular patch of territory you are trying to image....
Well until I see something to the contrary I'm going to take the article at face value as their usually a reputable source of news.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #137 on: 12/19/2014 11:51 pm »
Well until I see something to the contrary I'm going to take the article at face value as their usually a reputable source of news.
The article talks about ramjets not being able to ignite below M4.0.

This is incorrect. The BOMARC  and Talos ramjet missile programmes fielded 100s of missiles each, all running below M4.0.

It appears the author has confused supersonic combustion (SC)ramjets with ordinary ramjets.

Which straightaway makes there grasp of the subject look very shaky.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #138 on: 12/20/2014 08:52 am »
Well until I see something to the contrary I'm going to take the article at face value as their usually a reputable source of news.
The article talks about ramjets not being able to ignite below M4.0.

This is incorrect. The BOMARC  and Talos ramjet missile programmes fielded 100s of missiles each, all running below M4.0.

It appears the author has confused supersonic combustion (SC)ramjets with ordinary ramjets.

Which straightaway makes there grasp of the subject look very shaky.  :(

I'm not sure you can use that example as its a missile engine and as you very well should know a missile engine is a very different prospect than an aircraft engine. A missile engine is usually only required for a relatively short space of time propelling an object far smaller than an aircraft. For example the infamous pulse detention engine can be used for missiles but it doesn't mean it's appropriate for an aircraft. So for the author to say this in terms of aircraft propulsion seems entirely in order.
« Last Edit: 12/20/2014 08:53 am by Star One »

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #139 on: 12/20/2014 11:24 am »
I'm not sure you can use that example as its a missile engine and as you very well should know a missile engine is a very different prospect than an aircraft engine. A missile engine is usually only required for a relatively short space of time propelling an object far smaller than an aircraft.

The physics of a ramjet don't care if it's sitting on a crewed vehicle or a drone. It is factually wrong that a ramjet cannot be ignited below M 4.0.  My guess is the author has confused a ramjet with a scramjet. Something anyone with some familiarity with the subject would never do. 
Quote
For example the infamous pulse detention engine can be used for missiles but it doesn't mean it's appropriate for an aircraft. So for the author to say this in terms of aircraft propulsion seems entirely in order.
AFAIK the first flight test for a PDE was a crewed aircraft. In fact a PDE should be more flexible than a ramjet as some of its parameters are easier to vary.

You need to do more reading around this technology.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #140 on: 12/20/2014 09:50 pm »

I'm not sure you can use that example as its a missile engine and as you very well should know a missile engine is a very different prospect than an aircraft engine. A missile engine is usually only required for a relatively short space of time propelling an object far smaller than an aircraft.

The physics of a ramjet don't care if it's sitting on a crewed vehicle or a drone. It is factually wrong that a ramjet cannot be ignited below M 4.0.  My guess is the author has confused a ramjet with a scramjet. Something anyone with some familiarity with the subject would never do. 
Quote
For example the infamous pulse detention engine can be used for missiles but it doesn't mean it's appropriate for an aircraft. So for the author to say this in terms of aircraft propulsion seems entirely in order.
AFAIK the first flight test for a PDE was a crewed aircraft. In fact a PDE should be more flexible than a ramjet as some of its parameters are easier to vary.

You need to do more reading around this technology.

I'm somewhat bemused that you think that just because technology works on a missile that it means it's appropriate for an aircraft. If it was that easy I'm sure we would have had hypersonic aircraft by now.

Offline Nilof

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #141 on: 12/20/2014 10:12 pm »
I'm somewhat bemused that you think that just because technology works on a missile that it means it's appropriate for an aircraft. If it was that easy I'm sure we would have had hypersonic aircraft by now.

That was the exact opposite of what he said?

Either way, the first ramjet-powered aircraft had a *top speed* of mach 0.85.  And it was definitely manned.

http://en.wikipedia.org/wiki/Leduc_0.10

Ramjets can certainly ignite well below supersonic speeds, just not from a standstill as is needed for takeoff. The main reason why they are not used is that fuel efficiency and the overall practicality of the full package has generally been a more important concern than top speed, and more complex engines with active compressors outperform ramjets in this aspect.
« Last Edit: 12/20/2014 10:13 pm by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline DMeader

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #142 on: 12/20/2014 10:26 pm »

The physics of a ramjet don't care if it's sitting on a crewed vehicle or a drone. It is factually wrong that a ramjet cannot be ignited below M 4.0.
I'm somewhat bemused that you think that just because technology works on a missile that it means it's appropriate for an aircraft. If it was that easy I'm sure we would have had hypersonic aircraft by now.

I'm somewhat bemused that you are purposefully refusing to understand what John is saying. He is correct, the engine doesn't know or care what sort of aircraft it is attached to. What is "appropriate" is an entirely different matter and outside the scope of this discussion.

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #143 on: 12/21/2014 11:26 am »
I'm somewhat bemused that you are purposefully refusing to understand what John is saying. He is correct, the engine doesn't know or care what sort of aircraft it is attached to. What is "appropriate" is an entirely different matter and outside the scope of this discussion.
Indeed. It's hard to understand how someone could be so vested in a report (unless the wrote it of course).  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #144 on: 12/22/2014 03:59 pm »
I'm somewhat bemused that you are purposefully refusing to understand what John is saying. He is correct, the engine doesn't know or care what sort of aircraft it is attached to. What is "appropriate" is an entirely different matter and outside the scope of this discussion.
Indeed. It's hard to understand how someone could be so vested in a report (unless the wrote it of course).  :(

I'm not invested in the report or have written it, just that I'd rather give it more weight in this case than some person posting on a forum.

As for people finding it funny that NASA should be doing this research for a seemingly military project must have forgotten that NASA Aeronautics & the USAF signed a MOU back in 2006 to as it says on their website:

In August 2006, NASA and the U.S. Air Force signed a Memorandum of Understanding (MOU) to formalize a new aeronautics research partnership. The MOU ensures the free exchange of research information, reduces duplication of research, and enhances long-term research planning on advanced aircraft design, propulsion development, materials development, and aviation safety.
« Last Edit: 12/22/2014 04:17 pm by Star One »

Offline DMeader

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #145 on: 12/22/2014 04:38 pm »
I'm not invested in the report or have written it, just that I'd rather give it more weight in this case than some person posting on a forum.

As for people finding it funny that NASA should be doing this research for a seemingly military project must have forgotten that NASA Aeronautics & the USAF signed a MOU back in 2006 to as it says on their website:

In August 2006, NASA and the U.S. Air Force signed a Memorandum of Understanding (MOU) to formalize a new aeronautics research partnership. The MOU ensures the free exchange of research information, reduces duplication of research, and enhances long-term research planning on advanced aircraft design, propulsion development, materials development, and aviation safety.

That's quite a reach to conclude that NASA is  "doing this research for a seemingly military project". A bias is showing up here.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #146 on: 12/22/2014 09:19 pm »
There's some legitmate question on the article information but it DOES point out that the main questin is can a duel-mode ramjet start at lower speeds and it should be recalled that for the most part a ramjet has a "range" of about three or so "Mach" above start-up. So a Mach-2.2 ramjet can probably hit Mach-5 HOWEVER SCramjets haven't had a lot of luck getting going well under Mach-6/7 so there is a definate need to "up" the low end of things.

The main "issue" at hand is if a SCramjet is really needed at all for the proposal. Given the "SR-72" as it keeps getting called is supposed to "cruise" at somewhere around Mach-6/7 which a "plain" old subsonic combustion ramjet will handle (granted its got to be designed to START around Mach-4 but we've actually DONE that before :) ) I have to wonder if the SCramjet is even worth the effort.
(And there's the pertent line: “We’re looking for a turbine-based combined system where at low speeds you have a turbine providing power, then at higher speeds a ramjet or scramjet takes over")

Mach-4 with a "standard" F100 should be possible with MIPCC for boost and Mach capability increase, a standard subsonic combustion ramjet from there to Mach-7 "cruise" (actually the Mach-7 part is a 'dash' and the vehicle will probably "cruise" supersonic) and then back down to turbine power for return and landing. Still not sure I buy the idea that "hypersonic" is the new stealth though, unless you're coming in below 40,000ft (which at Mach-7 would be a real trick) most radars will still have time to pick you up and generate a tracking solution.

Still if you can get an airframe that can handle, say, a 20 minute 'dash' at Mach-7 below 80,000ft you'd have quite a hard target to hit.

Not much use as a space launcher though :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline dror

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #147 on: 12/23/2014 03:30 pm »
Sorry to interrupt  ::),
I'm looking for the xs1 thread, is it here?
Space is hard immensely complex and high risk !

Offline john smith 19

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #148 on: 12/24/2014 12:13 am »
There's some legitmate question on the article information but it DOES point out that the main questin is can a duel-mode ramjet start at lower speeds and it should be recalled that for the most part a ramjet has a "range" of about three or so "Mach" above start-up. So a Mach-2.2 ramjet can probably hit Mach-5 HOWEVER SCramjets haven't had a lot of luck getting going well under Mach-6/7 so there is a definate need to "up" the low end of things.
Or technically "down" (below M6/7)
Quote
The main "issue" at hand is if a SCramjet is really needed at all for the proposal. Given the "SR-72" as it keeps getting called is supposed to "cruise" at somewhere around Mach-6/7 which a "plain" old subsonic combustion ramjet will handle (granted its got to be designed to START around Mach-4 but we've actually DONE that before :) ) I have to wonder if the SCramjet is even worth the effort.
(And there's the pertent line: “We’re looking for a turbine-based combined system where at low speeds you have a turbine providing power, then at higher speeds a ramjet or scramjet takes over")

Mach-4 with a "standard" F100 should be possible with MIPCC for boost and Mach capability increase, a standard subsonic combustion ramjet from there to Mach-7 "cruise" (actually the Mach-7 part is a 'dash' and the vehicle will probably "cruise" supersonic) and then back down to turbine power for return and landing. Still not sure I buy the idea that "hypersonic" is the new stealth though, unless you're coming in below 40,000ft (which at Mach-7 would be a real trick) most radars will still have time to pick you up and generate a tracking solution.
I think LM are playing a very astute game.

Concorde proved a large turbojet aircraft can super cruise without afterburner for hours at a time without damage at M2.2, and of course the SR71 proved they could run in 'burner for hours at a time too.

A range of 3 Mach numbers is well inside the ramjet knowledge base so LM has 3 options.

I think it's plausible (although I'm not sure if it's been tested) that the kind of military low BPR turbofans the military favor can survive up to M2.2 as well.

So M6 - M3 - M2.2 = M0.8

So (in principle) what's needed is some way to bridge that extra M0.8. Drop the SCramjet ignition speed, widen the ramjet operating speed range, or a bit of both, and hey presto you're home free.  :)

While thinking about this problem I will note there is a non obvious split in the engine duties. Instead of turbo-something and ram/SCramjet how about subsonic and non subsonic inlets?

In this view the flow path starts without slowing the flow and has some kind of diverter arrangement (I'm thinking like a set of louvres).

At low speed the louvres are at (relatively) high angle and direct the flow into the turbine/ramjet section, with it's associated shock paths, flame holders etc.

At higher speed the blades flatten out to horizontal and point the flow at the SCramjet path, simultaneously directing the now very hot air stream straight into the SCRamjet duct with minimal drag. 

It all sound desperately complicated to me but it might work. I'd like to think they've come up with some elegant, tricky fluidic solution (something exploiting the Coanda effect?) but fluid dynamics is not really my strong suite.

BTW would you say M6 is above the point where the engine and the vehicle have to be designed together or can they still get away with "dropping in" an engine package?  I don't think they can. I also think they'll need to go to higher altitude to sidestep (partly) the heating issues. 80 000 ft?

Whatever the solution it's pretty clear this is not going to be cheap.
Quote
Not much use as a space launcher though :)
True.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Vultur

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #149 on: 12/24/2014 01:59 am »
Not much use as a space launcher though :)

Why is that? Mach 7 at fairly high altitude sounds like it would be a significant delta v gain, likely enough for 1 stage to orbit. Is there just not enough payload for a significant rocket? Or just too expensive?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #150 on: 12/24/2014 05:32 pm »
Sorry to interrupt  ::),
I'm looking for the xs1 thread, is it here?
XS-1 (I'm sorry but is anyone ELSE amused as I am over that designation? :) is supposed to be pure rocket powered and be capable of reaching Mach-10 at least once. The "SR-72" doesn't seem to be capable or designed to much exceed Mach-7 so it's probably not even close :)

Not much use as a space launcher though :)

Why is that? Mach 7 at fairly high altitude sounds like it would be a significant delta v gain, likely enough for 1 stage to orbit. Is there just not enough payload for a significant rocket? Or just too expensive?

Except the "SR-72" is specifically NOT going to do so at any significant altitude by the descriptions we've been seeing. Doing Mach-7 at or below 80,000ft is probably acceptable for a recon/strike platform, for an effective launch platform you want to be significantly higher (probably over 100,000ft) at that speed for the purposes of seperation of a second stage. It's also supposed to be an RPV/Drone so I highly doubt it would have an effective payload capability that could launch something that can go the rest of the way up to Mach-25/Orbit.

Having said all that I WILL point out that once you have designed and built engines capable of going from zero-to-Mach-7 in air-breathing mode you will have done a significant amount of work towards being able to build a Mach-7 launch platform. It just won't be the SR-72 :)

My personal "boggle" here is I suspect that the insistance on specifically requireing a Supersonic-Combustion-ramjet (SCramjet) is going to be the long-pole in the whole project and frankly I don't as of yet see a valid reason they "have" to have one. But that's the requirement.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #151 on: 12/24/2014 05:57 pm »
I think LM are playing a very astute game.

I think so too... But the I'm wondering if the "game" they are playing is simply keep dragging this program out for as long as possible :)

Quote
Concorde proved a large turbojet aircraft can super cruise without afterburner for hours at a time without damage at M2.2, and of course the SR71 proved they could run in 'burner for hours at a time too.

A range of 3 Mach numbers is well inside the ramjet knowledge base so LM has 3 options.

I think it's plausible (although I'm not sure if it's been tested) that the kind of military low BPR turbofans the military favor can survive up to M2.2 as well.

So M6 - M3 - M2.2 = M0.8

So (in principle) what's needed is some way to bridge that extra M0.8. Drop the SCramjet ignition speed, widen the ramjet operating speed range, or a bit of both, and hey presto you're home free.  :)

While thinking about this problem I will note there is a non obvious split in the engine duties. Instead of turbo-something and ram/SCramjet how about subsonic and non subsonic inlets?

In this view the flow path starts without slowing the flow and has some kind of diverter arrangement (I'm thinking like a set of louvres).

At low speed the louvres are at (relatively) high angle and direct the flow into the turbine/ramjet section, with it's associated shock paths, flame holders etc.

At higher speed the blades flatten out to horizontal and point the flow at the SCramjet path, simultaneously directing the now very hot air stream straight into the SCRamjet duct with minimal drag. 

It all sound desperately complicated to me but it might work. I'd like to think they've come up with some elegant, tricky fluidic solution (something exploiting the Coanda effect?) but fluid dynamics is not really my strong suite.

BTW would you say M6 is above the point where the engine and the vehicle have to be designed together or can they still get away with "dropping in" an engine package?  I don't think they can. I also think they'll need to go to higher altitude to sidestep (partly) the heating issues. 80 000 ft?

Whatever the solution it's pretty clear this is not going to be cheap.

As I understand the idea the Dual-Mode engine pretty much has the SCramjet engine in a direct path as you describe with the "normal" jets in a secondary duct "usually" in an over/under combination. The SCramjet in fact has two combustion sections in the diagrams I've seen. A "low-speed" one and a "high-speed" one essentially in the same duct so as to cover a wider speed range.

As for the required "speed" at which the vehicle/engine have to be "packaged" as a unit that's "generally" anything above Mach-3. But having said that you CAN still get away with "dropping" normal low-BPR-turbofans into the airframe, you just have to make sure the intakes and exhaust system works over a very wide range of speeds. You're very much correct that's going to "cost" though :) The inward-turning inlets and exhaust system should go a long way to helping with that.

Heating is going to be the main issue with this proposal no matter how you look at it. They can't really GO that high and still have the advantage of speed and low tracking time. For a SPACE launcher you in fact want BOTH high speed AND high altitude if you can get them (as well as a high AoA at seperation) but for a recon-strike package you pretty much need to keep as low as possible to keep your detection horizon as low as possible.

Offhand, from vauge memory at Mach-6 and less than 50,000ft altitude, from a ground based radar system you have less than 30 seconds to lock up and engage a target before it over-flies your radar site. In most cases that's a pretty difficult "shot" no matter how you look at it. However the detection time goes up the higher the target is above the "ground" level clutter and if you have a detection radar at 30,000ft (AWACS basicly) you're going to be "seeing" several minutes outward from your radar set. (It's one of the reason that very high altitude balloon born radar systems have been suggested. A radar at 80,000ft to 100,000ft over the East coast of the US can probably detect airborne targets as far away as the UK :) In fact I suspect that those kind of AWACS ideas are going to be coming back again with greater force as the technology to deploy something like the "SR-72" comes closer to operation)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Patchouli

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #152 on: 12/24/2014 06:51 pm »
If the hypersonic  aircraft can do do a pull up maneuver and get past or at at least close to the Kármán line separation of the upper stage could be relatively strait forwards and much simpler then it would be for a supersonic aircraft.
Because the problem of shock interaction during separation would be eliminated.
« Last Edit: 12/24/2014 06:52 pm by Patchouli »

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #153 on: 12/27/2014 06:58 pm »
I have now been able to verify the Flight Global news story via Popular Mechanics who actually included a link in their article.

Here is the article.

http://www.popularmechanics.com/technology/aviation/military/sr-72-lockheed-hypersonic-drone

Here is the NASA contract award to LM specifically for the SR-72 concept.

https://www.fbo.gov/index?s=opportunity&mode=form&tab=core&id=91410a244647775c646ac3224c94395d

Seems odd to see NASA fund something like this even as a concept.
« Last Edit: 12/30/2014 04:41 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #154 on: 12/30/2014 02:27 pm »
If the hypersonic  aircraft can do do a pull up maneuver and get past or at at least close to the Kármán line separation of the upper stage could be relatively strait forwards and much simpler then it would be for a supersonic aircraft.
Because the problem of shock interaction during separation would be eliminated.

The "idea" is used with supersonic seperation as well. RASCAL was only supersonic (little over Mach-1.5 at seperation) but did a "zoom" climb to allow low-Q seperation. The main issue is most of your air-breathing power plants will quit working well below the Karman line and you lose a great deal of velocity between engine cut off and seperation. Granted you START with more being hypersonic (Mach-5+) but still speed bleeds off pretty quickly.

It's one (of the many) reasons why the idea of a non-airbreathing "secondary" component propulsion system is often seen in these ideas. (Normally a "secondary" rocket propulsion system but also why you see rocket-based-combined cycle powerplants suggested. The "rocket" portion continues to operate after the air-breathing system shuts down and being a "combined" powerplant means its slightly less massive than two seperate power plant systems)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #155 on: 12/30/2014 04:44 pm »
If the hypersonic  aircraft can do do a pull up maneuver and get past or at at least close to the Kármán line separation of the upper stage could be relatively strait forwards and much simpler then it would be for a supersonic aircraft.
Because the problem of shock interaction during separation would be eliminated.

The "idea" is used with supersonic seperation as well. RASCAL was only supersonic (little over Mach-1.5 at seperation) but did a "zoom" climb to allow low-Q seperation. The main issue is most of your air-breathing power plants will quit working well below the Karman line and you lose a great deal of velocity between engine cut off and seperation. Granted you START with more being hypersonic (Mach-5+) but still speed bleeds off pretty quickly.

It's one (of the many) reasons why the idea of a non-airbreathing "secondary" component propulsion system is often seen in these ideas. (Normally a "secondary" rocket propulsion system but also why you see rocket-based-combined cycle powerplants suggested. The "rocket" portion continues to operate after the air-breathing system shuts down and being a "combined" powerplant means its slightly less massive than two seperate power plant systems)

Randy

In relation to this why is NASA giving money to LM to study an engine concept in this area, shouldn't it be the USAF's money? I know as I mentioned above that NASA Aeronautics works with the USAF, but it still seems mildly strange. If it goes beyond a concept study surely NASA are not going to start funding that as well.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #156 on: 12/30/2014 06:38 pm »
Included in this PPT presentation is a notional B-58 "sized" HTOL vehicle for Mach-3 release...
http://www.responsivespace.com/Papers/RS2/SESSION%20PAPERS/SESSION%207/JOYNER/7001C.ppt

Sadly, getting something like this up to "hypersonic" range (Mach-5+) would be a major challenge and probably far to much money..

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #157 on: 12/30/2014 06:45 pm »
In relation to this why is NASA giving money to LM to study an engine concept in this area, shouldn't it be the USAF's money? I know as I mentioned above that NASA Aeronautics works with the USAF, but it still seems mildly strange. If it goes beyond a concept study surely NASA are not going to start funding that as well.

Look at the amount of money cited, less than 900 thousand for a "parametric feasability" study which has pretty much been "done" to death already... The award is justifiable under the NASA "aeronautics" propulsion mandate but probably barely. At a guess here I'm thinking this is an "offset" look at possible near-term propulsion concepts to be mated with the DMRJ described and very much less anything aimed at actually achieving anything equipment wise. (IIRC this is around the same "price" range that AFIT is spending on the proposed study of the SABRE cycle from REL so I'm guessing this is the SCramjet folks response to that engine work. After all we all KNOW how superior a Mach-7+ SCramjet engine is going to be to any thing as "piddly" as a Mach-5 engine right? We just need to keep hammering that "possibility" over the heads of anyone who insists on something that might actually, you know, work anytime in the near future :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #158 on: 12/30/2014 07:41 pm »
In relation to this why is NASA giving money to LM to study an engine concept in this area, shouldn't it be the USAF's money? I know as I mentioned above that NASA Aeronautics works with the USAF, but it still seems mildly strange. If it goes beyond a concept study surely NASA are not going to start funding that as well.

Look at the amount of money cited, less than 900 thousand for a "parametric feasability" study which has pretty much been "done" to death already... The award is justifiable under the NASA "aeronautics" propulsion mandate but probably barely. At a guess here I'm thinking this is an "offset" look at possible near-term propulsion concepts to be mated with the DMRJ described and very much less anything aimed at actually achieving anything equipment wise. (IIRC this is around the same "price" range that AFIT is spending on the proposed study of the SABRE cycle from REL so I'm guessing this is the SCramjet folks response to that engine work. After all we all KNOW how superior a Mach-7+ SCramjet engine is going to be to any thing as "piddly" as a Mach-5 engine right? We just need to keep hammering that "possibility" over the heads of anyone who insists on something that might actually, you know, work anytime in the near future :)

Randy

In your opinion do you think this is the last we'll hear of this particular approach?

You're of the view that it's unlikely too result in actual metal being bent on some kind of propulsion demonstrator?
« Last Edit: 12/30/2014 07:49 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #159 on: 12/30/2014 08:34 pm »
In your opinion do you think this is the last we'll hear of this particular approach?

Not at all :) After all we still have folks out there promoting fully solid based launch vehicles so why on Earth would something like SCramjet (and specifically "low-mach" starting DMRJ engine SCramjet which won't "need" to get up to Mach-7 to start) which on paper is fully capable of "flying" to orbit (and beyond I might add as "theorectically" a SCramjet has NO "top-speed" or so the math says :) ) would ever go away?

More specifically, (or more "applicably" I suppose I should say) a turbo-RAMjet with speeds of up to Mach-8 from a "zero" start are something that this could enable IF we can get the SCramjet (sorry, need to stop here for a second and just say that I have to use stupid words to get my point across. I know that means I must have a weak argument, but that's why I use bad words). to ease off for a bit and THAT isn't a bad idea at all :)
Quote
You're of the view that it's unlikely too result in actual metal being bent on some kind of propulsion demonstrator?

As long as someone keeps their heads in of certain places and insists on the engine REQUIRING a SCramjet to be "workable" then yes I don't see anything much coming of this. (The main reason is that while having a turbojet that can be used to get the "SCramjet" up to speed assumes you have an operational "low-speed" SCramjet on hand, which we don't) The main attraction of the DMRJ is that it is in fact both a "ramjet" (Mach-4-6 or so) AND a SCramjet (which would take the vehicle from Mach-6 to "top-speed") but you DO in fact have to have a working DUAL-MODE engine to start with which we don't. Now we DO in fact have seveal designs on the books for RAMjets that can "cruise" at Mach-6 (which you will note is "hypersonic" if  not by much in comparision with the SCramjet) and in fact we even have designs for some engine cycles that while they don't use the tubojet as a base powerplant were studied enough to possibly build flight capable engines that can do the same the main issue is OTHER than the turboramjet (SR-71 in fact) none of these engines has ANY flight experiance to back up the works done and NONE of them are "proven" to fly hypersonically. The only engines that can make that claim are rockets and the few experimental SCramjets that may or may not actually be OPERATIONALLY capable of doing so.

I'd probably have more faith in the SR-72 stuff if;
1) LM hadn't already "mothballed" this project a couple of times
2) It wasn't NASA providing the money because as noted they actually have very little "reason" to financially support this type of project to operation
3) It wasn't a "parametric" study
4) It wasn't aimed specifically at providing the "feasability" of "off-the-shelf" engines to feed a notional DMRJ we don't as of yet have working

Frankly there are more "aero" reasons for the proposed engine system than "LV" reasons by far and it would be so much "simpler" to go with the "Beta" or Boeing TSTO air-launched concepts using rockets and high-speed turbojets (Mach-4 or so with MIPCC) to achieve than fooling around with ram or SCramjets.
http://robotpig.net/__aerospace/tsto.php?page=0
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920012293.pdf
(Though BETA-II does in fact use ramjets. I forgot about that)

Randy
(Note: I'd like to see someone, at some time, come up with a more recent review of the concepts that all used LH2 and see if operationally Methalox wouldn't be better but I don't see that happening either at the moment)
« Last Edit: 12/30/2014 08:36 pm by RanulfC »
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Using a hypersonic aircraft as a LEO launcher
« Reply #160 on: 12/30/2014 09:04 pm »
Thanks for the comprehensive response. Are you disappointed to see NASA using their money on something like this. I know it's not much money in the grand scheme of things but I'd rather see someone like DAPRA or the Air Force funding this not NASA.

By the way when you talk of the SR-72 already being mothballed were you thinking of the Blackswift project here which it doesn't seem that dissimilar from in concept.

I think the best approach to this whole idea would be a 'mothership' aircraft with some kind of parasite vehicle being the actual launcher & achieving hypersonic flight.
« Last Edit: 12/30/2014 09:16 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #161 on: 01/05/2015 05:24 pm »
Thanks for the comprehensive response. Are you disappointed to see NASA using their money on something like this. I know it's not much money in the grand scheme of things but I'd rather see someone like DAPRA or the Air Force funding this not NASA.

It's hard to be "diappointed" with NASA doing its job and paying for aerospace research. I would feel much better if the project seemed to have any chance of actually producing some flight hardware, and/or wasn't "tied" to having to use SCramjets in any way but...

I think DARPA has its hands full at the moment with the XS-1 project and I don't see the AF stepping in until there is some clear indication that the system could be made operational.

Quote
By the way when you talk of the SR-72 already being mothballed were you thinking of the Blackswift project here which it doesn't seem that dissimilar from in concept.

Blackswift was in fact mentioned as being a "precursor" of the SR-72 concept but I was more refering to references from early last year where DARPA had dropped work on the concept and the AF had declined to pick it up. As far as I can tell while this sort of stuff keeps the "concept" on life support it doesn't seem to indicate any significant work is being done.

Quote
I think the best approach to this whole idea would be a 'mothership' aircraft with some kind of parasite vehicle being the actual launcher & achieving hypersonic flight.

Depends greatly on which "idea" one is pursuing :)

I'd agree in most cases you want a smaller, (less expensive) vehicles for the "mission" of recon and/or strike and probably, prefeably exendable ones at that. However if the "idea" is to find an excuse to use SCramjets for some purpose at all.... :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #162 on: 01/05/2015 06:58 pm »

Thanks for the comprehensive response. Are you disappointed to see NASA using their money on something like this. I know it's not much money in the grand scheme of things but I'd rather see someone like DAPRA or the Air Force funding this not NASA.

It's hard to be "diappointed" with NASA doing its job and paying for aerospace research. I would feel much better if the project seemed to have any chance of actually producing some flight hardware, and/or wasn't "tied" to having to use SCramjets in any way but...

I think DARPA has its hands full at the moment with the XS-1 project and I don't see the AF stepping in until there is some clear indication that the system could be made operational.

Quote
By the way when you talk of the SR-72 already being mothballed were you thinking of the Blackswift project here which it doesn't seem that dissimilar from in concept.

Blackswift was in fact mentioned as being a "precursor" of the SR-72 concept but I was more refering to references from early last year where DARPA had dropped work on the concept and the AF had declined to pick it up. As far as I can tell while this sort of stuff keeps the "concept" on life support it doesn't seem to indicate any significant work is being done.

Quote
I think the best approach to this whole idea would be a 'mothership' aircraft with some kind of parasite vehicle being the actual launcher & achieving hypersonic flight.

Depends greatly on which "idea" one is pursuing :)

I'd agree in most cases you want a smaller, (less expensive) vehicles for the "mission" of recon and/or strike and probably, prefeably exendable ones at that. However if the "idea" is to find an excuse to use SCramjets for some purpose at all.... :)

Randy

I'm getting kind of tired of the whole hypersonic aircraft as a concept in this context. You kind of feel like saying either commit to develop related hardware or just let the whole thing die and stop resurrecting it under different names or at the very least adopt a more flexible approach in which they consider different technologies to achieve their aims.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #163 on: 01/05/2015 07:10 pm »
I'm getting kind of tired of the whole hypersonic aircraft as a concept in this context. You kind of feel like saying either commit to develop related hardware or just let the whole thing die and stop resurrecting it under different names or at the very least adopt a more flexible approach in which they consider different technologies to achieve their aims.

I've questioned the whole idea of a "hypersonic" aircraft as a launch assist from the start. Mostly due to the need to develop a "hypersonic" aircraft to begin with and yes technology wise its become quite clear we need to develop hypersonic propulsion of some type before we even begin to plan to build airframes that can use it and so far no one has been willing to actually put forth the effort to do so.

And overall the damn idea that "hypersonic" HAS to mean "SCramjet" is far to overdone and there needs to be a hard look taken at the whole basis and justification for "hypersonic" flight in the first place. I don't see it happening simply because there is no convincing reason to do so because no one is enough interersted TO do so.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Hog

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #164 on: 01/05/2015 08:24 pm »
Would any of the early STS proposals which included flyback boosters be considered a hypersonic aircraft?
Paul

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Using a hypersonic aircraft as a LEO launcher
« Reply #165 on: 02/18/2015 02:08 pm »
This is probably more applicable here than elsewhere. Annoyingly I cannot give you a direct link to the rest of the article as its on a pay site just the abstract on their public side.

Quote
DARPA Seeks Increased Spending For Hypersonic Air-Breathing Program

The Pentagon's advanced research arm seeks a nearly eight-fold funding increase in fiscal year 2016 on a joint program with the Air Force that focuses on flight demonstrations of critical hypersonic technologies.

But I imagine it was taken from this. See page 213 onwards.

http://www.darpa.mil/WorkArea/DownloadAsset.aspx?id=2147488711
« Last Edit: 02/18/2015 02:23 pm by Star One »

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #166 on: 02/19/2015 05:11 pm »
Would any of the early STS proposals which included flyback boosters be considered a hypersonic aircraft?

Depends how far back you're willing to "push" the STS designation I suppose :)

And how "inclusive" you're willing to be. Sanger-II had a hypersonic carrier aircraft but that was European.

If you're talking the 'actual' NASA STS "shuttle" studies then no because they were all rockets and all staging was done outside the effective atmosphere in a ballistic arc. All "flying" (by both the booster and orbiter) was done and low-supersonic to subsonic speeds.

The idea here is to have a carrier aircraft that is capable of flying in the atmosphere at hypersonic speed BEFORE pulling up to exit the atmosphere and stage as I understand it.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #167 on: 02/19/2015 05:16 pm »
This is probably more applicable here than elsewhere. Annoyingly I cannot give you a direct link to the rest of the article as its on a pay site just the abstract on their public side.

Quote
DARPA Seeks Increased Spending For Hypersonic Air-Breathing Program

The Pentagon's advanced research arm seeks a nearly eight-fold funding increase in fiscal year 2016 on a joint program with the Air Force that focuses on flight demonstrations of critical hypersonic technologies.

But I imagine it was taken from this. See page 213 onwards.

http://www.darpa.mil/WorkArea/DownloadAsset.aspx?id=2147488711

Lost interest the second they invoked "SCramjet" technology for the HAWC missile :)
The TBG is interesting as its a "boosted" hypersonic glider but since its using rockets to get to hypersonic speed it has limited applicability.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #168 on: 02/19/2015 07:04 pm »
This is probably more applicable here than elsewhere. Annoyingly I cannot give you a direct link to the rest of the article as its on a pay site just the abstract on their public side.

Quote
DARPA Seeks Increased Spending For Hypersonic Air-Breathing Program

The Pentagon's advanced research arm seeks a nearly eight-fold funding increase in fiscal year 2016 on a joint program with the Air Force that focuses on flight demonstrations of critical hypersonic technologies.

But I imagine it was taken from this. See page 213 onwards.

http://www.darpa.mil/WorkArea/DownloadAsset.aspx?id=2147488711

Lost interest the second they invoked "SCramjet" technology for the HAWC missile :)
The TBG is interesting as its a "boosted" hypersonic glider but since its using rockets to get to hypersonic speed it has limited applicability.

Randy
I did wonder what your reaction would be when you saw the mention of your favourite propulsion technology.:)

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #169 on: 02/19/2015 08:19 pm »
SCramjets look SO good in theory.. Reality has a bad tendency to get in the way though :)

I'd found a nice study on advanced ramjets at a collage library one time that pointed out that it past a certain speed even a SCramjet doesn't work because of physics so getting to orbit with one it right out the window. (Somewhere around Mach-15 IIRC the airflow becomes hot enough that even injecting hydrogen doesn't work to increase the flow energy. The suggestion was that energy could still be added through "non-conventional" means and if you read carefully enough you finally figured out they were talking a NUCLEAR SCramjet engine. Further on it was shown that around Mach-16+ the internal flow becomes "plasma-like" and NO amount of added energy "helps" keep the vehicle accelerating. And the paper was written in the early 70s I think :) )

I'm really not figuring that SCramjets have ANYTHING to do with ETO (Earth-To-Orbit) launch as nothing I've seen in the past 20 years (not even NASP sad to say) has convinced me they have or anyone has any plans for using them in such a role. The bottom line is they are wanted as weapons propulsion and any "argument" for their use begins and ends there since their "role" can easily be covered by standard sub-sonic combustion ramjets or similar, more 'near-term' engines such as the SABRE, SERJ, or other designs without having to finance and develop a working SCramjet.

Unfortunately, "hypersonic" has become linked to SCramjets even though they have yet to actually "fly" successfully enough to be considered anything but a "research and development" program.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

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Using a hypersonic aircraft as a LEO launcher
« Reply #170 on: 02/26/2015 09:47 pm »
I suppose another way to go is to effectively combine launcher and plane together with an atmosphere skipping vehicle, then you'd only need an upper kick stage to deploy your payload at the relevant moment. The only mention of something a little like this I can find online is the HyperSoar and I suppose the concept has really been superseded by a full on spaceplane like Skylon.

Found this related thread.

http://forum.nasaspaceflight.com/index.php?topic=32261.0
« Last Edit: 02/26/2015 09:54 pm by Star One »

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #171 on: 03/03/2015 01:56 pm »
Will have to find it. but there was a study paper published years ago that proposed a sled-launched "first-stage" vehicle that internally carried an orbital second stage that then used "skip-gliding" and external burning (during the atmospheric portions of the "skip-glide) to achieve full global flight while never "actually" exceeding Mach-10 on average. Really the only memorable part of the paper was the information that tests had shown a great deal of benefit for external burning that allowed much higher hypersonic L/D than any previous work. We've actually known for decades that external burning increases lift and reduces drag at supersonic speeds but no one had carried it forward for study at hypersonic speeds and it turns out its even better used there.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #172 on: 03/04/2015 07:04 pm »
SCramjets look SO good in theory.. Reality has a bad tendency to get in the way though :)

I'd found a nice study on advanced ramjets at a collage library one time that pointed out that it past a certain speed even a SCramjet doesn't work because of physics so getting to orbit with one it right out the window. (Somewhere around Mach-15 IIRC the airflow becomes hot enough that even injecting hydrogen doesn't work to increase the flow energy.
Randy
You may have ruled out SSTO SCramjets as feasible; maybe not. But pro engineers (don't know if you are one)
always find a solution if physics allows. Tunnel vision opinions tend to ignore workaround solutions like converting part of the air sucked in to temporarily stored oxidizer (LOX); or making a hybrid propulsion system, etc.

Offline RanulfC

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Re: Using a hypersonic aircraft as a LEO launcher
« Reply #173 on: 03/04/2015 09:17 pm »
SCramjets look SO good in theory.. Reality has a bad tendency to get in the way though :)

I'd found a nice study on advanced ramjets at a collage library one time that pointed out that it past a certain speed even a SCramjet doesn't work because of physics so getting to orbit with one it right out the window. (Somewhere around Mach-15 IIRC the airflow becomes hot enough that even injecting hydrogen doesn't work to increase the flow energy.
Randy
You may have ruled out SSTO SCramjets as feasible; maybe not. But pro engineers (don't know if you are one)
always find a solution if physics allows. Tunnel vision opinions tend to ignore workaround solutions like converting part of the air sucked in to temporarily stored oxidizer (LOX); or making a hybrid propulsion system, etc.

NOT a pro so its only MHO :) The problem is if you read the history, the "math" is the basis and one or two "high profile" experts early in the 1950s were the ones who pushed SCramjets. BECAUSE they were "respected experts" their opinion carried a huge amount of weight and because the "math" looked solid (and it IS solid as long as you don't let little things like real physics get in the way) it became a basic "assumption" that it was true.

And on paper the SCramjet WILL allow an aircraft to go from a runway to orbit and back because they ARE that good. On paper. And the main point is probably that they are wholly dedicated to getting an AIRCRAFT to orbit instead of being part of a SPACECRAFT propulsion system.

And because they were going to be "that good" they got included in every design possible. Even if they don't fit or work for that design. Worse they became a "perfect" enemy of "good-enough" and designs and concepts that did NOT have them were set aside despite the lack of progress on SCramjet as an operational engine. And we have yet to get into the "issues" with the various TYPES of SCramjet, which was as divisive and cut-throat as any other research program :)

I've no doubt that engineers WILL eventually get them to work and they will become operational. But I question the basic assumption that they are NEEDED to air-breath as a viable method of getting to orbit. SERJ, Turbo-LACE, deep-cooled Turbo-Ramjets, to name just a few built and tested engines which simply lack flight experience are engine cycles that have far more near-term usability than waiting for the engineers to wring out SCramjets.

But they are not considered. At all. And the only obvious reason that can be seen is that SCramjets get suggested and promoted for each and every role they might be used for and THAT because of the "potential" of SCramjets.
"Someday soon" (tm).
 :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

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