Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 440684 times)

Offline SICA Design

  • Full Member
  • *
  • Posts: 179
  • UK
  • Liked: 41
  • Likes Given: 51
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #120 on: 02/26/2015 03:43 PM »
You're perhaps thinking of the Olympus engine tests for Concorde, where (IIRC) a test engine for the Concorde version was mounted underneath a Vulcan bomber (powered by 4 more of them). IE roughly 1/4 the full thrust of the aircraft, Or the LASRE tests planned for NASA's SR71 in the X33 programme.

The trouble is a full size SABRE has roughly 4.5x the thrust of all the engines on an Airbus 380, and that won't even get you to Mach 1.  :(

I wonder, could they build a full-scale SABRE but 1/4 power, i.e. fit some dummy (blanking) HX modules, only fit 1-of-4 combustion chambers / nozzles. Not sure how this would affect the compressor and other cooling loop / turbo machinery. Aim being to reduce power to suit smaller airframe, but still get relevant test results from full-scale components.

Any merit to this?

Offline adrianwyard

  • Full Member
  • ****
  • Posts: 955
  • Liked: 172
  • Likes Given: 220
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #121 on: 02/26/2015 04:30 PM »
We've certainly heard that the back end of SABRE is in essence two rocket engines driving four thrust chambers, and shutting down two of them is a planned failure mode. If that's still the case, half power in the test engine should be easy enough, and then add in whatever throttle-range it has.

Has minimum throttleable thrust ever come up before? This might be another reason to prefer E/D nozzles. IIUC wthout them Skylon startup thrust will need to be higher, and with SABRE's separated on wing-tips assymmetrical startup would be problematic.

Offline adrianwyard

  • Full Member
  • ****
  • Posts: 955
  • Liked: 172
  • Likes Given: 220
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #122 on: 02/26/2015 04:54 PM »
Interesting - I missed the change away from the 'dissected rabbit'. Hopefully that's indicative of confidence in all the theoretical and simulation work they've done, rather than impatience.

Any idea if what they're building includes everything, i.e. combustion chambers, nozzles, bypass burners, etc?

And does this match up with the phasing they mentioned in 2013 - where 3a included SCEPTRE? A near-flight-worthy engine is much more ambitious (expensive) than what I was expecting.

From Jeremy Nickless' talk last December http://forum.nasaspaceflight.com/index.php?topic=34964.msg1298468#msg1298468

Quote from: SICA Design
Phases 3 & 4 of the £10bn project now stretch over 10.5 years, of which £3.64bn is for SABRE. Phase 3 (£0.36bn) commenced April 2014 and approximately £100m has been secured, with approx £250m to secure in the next few years. Phase 4 is due to commence October 2018, with a (new) Skylon in-service date of October 2024.

Valkyrie? - "Could not possibly comment on that". Phase 3 WILL however involve a flying SABRE engine (not Skylon).
:
:
Quote
My impression was a single full-size SABRE with wings and tank

Thanks. You know, for a project that's not due until the mid 2020s we generate a lot of messages!

I would love to know how much of the 'build a flying SABRE' plan is dependent on the next £250m coming in, and what happens if it's late, or doesn't materialise. Here are a couple of options, one very cautious, and one not:

1] Spend the £100m to complete more ground-based component testing. Start work on the flyable Skylon when/if the £250m comes in. If it hasn't showed up when the £100m has been spent, REL goes into quiet mode awaiting money. Alan Bond retires soon thereafter, but the company continues.

2] Start spending the £100m to get ~ 1/3 of the way to a flying SABRE. If no-ones comes forth with the needed £250m to finish it, wasting that £100m will not reflect well on REL.

Online john smith 19

  • Senior Member
  • *****
  • Posts: 6182
  • Everyplaceelse
  • Liked: 822
  • Likes Given: 5138
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #123 on: 02/26/2015 06:50 PM »
I would love to know how much of the 'build a flying SABRE' plan is dependent on the next £250m coming in, and what happens if it's late, or doesn't materialise. Here are a couple of options, one very cautious, and one not:

1] Spend the £100m to complete more ground-based component testing. Start work on the flyable Skylon when/if the £250m comes in. If it hasn't showed up when the £100m has been spent, REL goes into quiet mode awaiting money. Alan Bond retires soon thereafter, but the company continues.

2] Start spending the £100m to get ~ 1/3 of the way to a flying SABRE. If no-ones comes forth with the needed £250m to finish it, wasting that £100m will not reflect well on REL.
The obvious route is to build and test the engine on the ground but plan the necessary features for it to be installed in an airframe.

REL have shown they are very careful at structuring the work they have to do relative to the funds they have.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline adrianwyard

  • Full Member
  • ****
  • Posts: 955
  • Liked: 172
  • Likes Given: 220
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #124 on: 02/26/2015 07:02 PM »
Sounds sensible. I wonder how much of a ground-based SABRE they can build for the £100m they have in hand. If most/all, we can reasonably expect to see something engine-shaped being built in Oxford over the next few years.

Edit: just went back to the January press release, and that says static test 'before the end of the decade.' So the flying SABRE test vehicle is early 2020s, which leads me to think that the additional £250m is needed to get through the static test.
« Last Edit: 02/26/2015 07:53 PM by adrianwyard »

Offline space_britannia

  • Member
  • Posts: 7
  • UK
  • Liked: 1
  • Likes Given: 0
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #125 on: 03/01/2015 03:14 AM »
2) deliver the specifically designed lander into space, and bring the squad there when it is needed.

The lander-in-orbit would be limited to a single window in a single orbital plane, making it incompatible with the goal of a suborbital ballistic "drop-ship" to allow any point-to-point travel in 90 minutes or so.

Just to make sure everyone's on the same page, the actual SUSTAIN/Hot Eagle requirements had the vehicle being capable of P2P travel OR being put into orbit as a "standby" measure for "drop" at any point up to several days later.

The conflicting requirements of those two mission parameters were something that was never addressed and would drive a "vehicle" design that would be very costly to meet both requirements.

Randy

Just considering the first one then, since they would seem impossible to reconcile, what they have in mind would seem to be an LH2-fuelled skylon-like carrier, dropping a jet-fuelled lander (since ability to retrieve troops and craft was a desired characteristic), equipped with heat shielding.

Even if a suitable heat shield material was available, the main problem seems to be with the skyon-like carrier - what happens to it after release? If it goes to orbit once-around, then maximum payload for the lander is limited to in the region of Skylon's 15 tons. If it is on a suborbital trajectory, it would re-enter in uncontrolled airspace, and would have to be refuelled at a LH2-capable runway.
 
Build a heat-shielded jet aircraft lighter than 15 tons or maintain a network of LH2-capable runways in hostile regions, neither seems particularly feasible

Online john smith 19

  • Senior Member
  • *****
  • Posts: 6182
  • Everyplaceelse
  • Liked: 822
  • Likes Given: 5138
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #126 on: 03/01/2015 09:27 AM »
Build a heat-shielded jet aircraft lighter than 15 tons or maintain a network of LH2-capable runways in hostile regions, neither seems particularly feasible
Correct.

The CRADA is about specifically about the SABRE engine cycle.

If they'd wanted Hypersonic cruise I'm quite sure they'd have requested more information on the LAPCAT work for M5 cruise.

Put it this way, if they are not looking at SABRE for use in a launch vehicle they are very foolish.  :(
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Citizen Wolf

  • Full Member
  • *
  • Posts: 159
  • Milky Way, Western spiral arm
  • Liked: 27
  • Likes Given: 28
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #127 on: 03/01/2015 02:31 PM »
If it's just the engine cycle itself, ie the thermodynamic cycle, then it probably doesn't need to include any specific  information on the heat exchangers and frost control mechanisms.

And is it the SABRE 3 or SABRE 4 engine cycle?

What might the USAF gain from studying the thermodynamics of the engine cycle?  ie what applications or insights might it give them for future planning? Is it like JS19 suggests - the only real reason for studying the cycle in this engine is to look at possible applications for launch capacity only.
« Last Edit: 03/01/2015 02:34 PM by Citizen Wolf »
The only thing I can be sure of is that I can't be sure of anything.

Online john smith 19

  • Senior Member
  • *****
  • Posts: 6182
  • Everyplaceelse
  • Liked: 822
  • Likes Given: 5138
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #128 on: 03/01/2015 05:37 PM »
If it's just the engine cycle itself, ie the thermodynamic cycle, then it probably doesn't need to include any specific  information on the heat exchangers and frost control mechanisms.
It will contain specific information regarding things like mass flow rates, temperature differences and inlet and out let temperatures (on both fluids). At this level it's mathematics. How those features are implemented is another question entirely.
Quote
And is it the SABRE 3 or SABRE 4 engine cycle?
This has been mentioned. It'll be SABRE 3 as that can be compared with the work funded by ESA and done at the Von Karman institute. That means the USAFRL can set up the same input conditions and expect the same output conditions. If that doesn't happen then someone has implemented the model of the engine wrong, which is a very handy thing to find out.

AFAIK the detailed performance of the SABRE 4 cycle are still private to REL.
Quote
What might the USAF gain from studying the thermodynamics of the engine cycle?  ie what applications or insights might it give them for future planning? Is it like JS19 suggests - the only real reason for studying the cycle in this engine is to look at possible applications for launch capacity only.
Have seen how much the USAF spends on launch only.

Gwen Shotwell at her NATO presentation said to the effect that "National Security Space launch is the US space launch market and you have to be in it to a major player in US space launch."
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline MichaelBlackbourn

  • Member
  • Posts: 41
  • Liked: 63
  • Likes Given: 0
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #129 on: 03/01/2015 06:00 PM »
Any chance we can hack a ramp into the bottom of the payload bay for paratrooper deployment? Baumgartner up some airborne troops and fire them off the back of the ramp.

How does the payload bay compare to a c130 in number of troopers. And can the craft slow down long enough and low enough to deploy them and then land far downrange? :)

Or maybe a disposable frame that gets ejected and then drops the troops.


Offline Citizen Wolf

  • Full Member
  • *
  • Posts: 159
  • Milky Way, Western spiral arm
  • Liked: 27
  • Likes Given: 28
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #130 on: 03/01/2015 06:36 PM »
JS19
**It'll be SABRE 3**

I missed that info. Thanks. :)
The only thing I can be sure of is that I can't be sure of anything.

Offline space_britannia

  • Member
  • Posts: 7
  • UK
  • Liked: 1
  • Likes Given: 0
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #131 on: 03/01/2015 07:51 PM »
Build a heat-shielded jet aircraft lighter than 15 tons or maintain a network of LH2-capable runways in hostile regions, neither seems particularly feasible
Correct.

The CRADA is about specifically about the SABRE engine cycle.

If they'd wanted Hypersonic cruise I'm quite sure they'd have requested more information on the LAPCAT work for M5 cruise.

Put it this way, if they are not looking at SABRE for use in a launch vehicle they are very foolish.  :(

Clearly they are looking at launch rather than hypersonic cruise, my question is if it is SUSTAIN they have in mind then how are they going to make this sabre carrier / turbojet lander architecture work

Online john smith 19

  • Senior Member
  • *****
  • Posts: 6182
  • Everyplaceelse
  • Liked: 822
  • Likes Given: 5138
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #132 on: 03/02/2015 08:33 AM »
Clearly they are looking at launch rather than hypersonic cruise, my question is if it is SUSTAIN they have in mind then how are they going to make this sabre carrier / turbojet lander architecture work
Welcome to the forum.

The answer is rather obviously with extreme difficulty. :(
« Last Edit: 03/02/2015 09:03 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Online john smith 19

  • Senior Member
  • *****
  • Posts: 6182
  • Everyplaceelse
  • Liked: 822
  • Likes Given: 5138
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #133 on: 03/02/2015 10:05 PM »
Any chance we can hack a ramp into the bottom of the payload bay for paratrooper deployment? Baumgartner up some airborne troops and fire them off the back of the ramp.

How does the payload bay compare to a c130 in number of troopers. And can the craft slow down long enough and low enough to deploy them and then land far downrange? :)

Or maybe a disposable frame that gets ejected and then drops the troops.
Welcome to the forum.

The bay is about  4.8m wide and about 16 m long. There is no option for a "tail ramp" type drop.

Unfortunately you're either going to need various bases at different longitudes to minimize plane change payload losses or  you have a fairly small minimum team the system can use.

If the vehicle is staying orbital to land further along track or plane change back to its launch base that means the personnel are carrying out individual reentries, or you have to do an orbital ejection of a re entry capable lander module while keeping the vehicle in tact. Either way a huge challenge.  Probably the closest to this architecture is the "Q bay" of the U2 and it's developments, built as a simple rectangular duct running top to bottom, but I'm not sure what facilities it supplied to the payload or if they were more or less self contained.

Option B is to have the vehicle already into a reentry so a chunk of velocity is already lost. Now you're looking at something like an ejection. The highest is about M3 from an SR71, however it seems due to the altitude (around 80 k feet) which apparently equates to something like 400mph.

This is one of those sounds-cool-but-is-really-nonsense ideas that's great for the plot of a straight-to-download action movie.

IRL not really that good.  :(

"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline SICA Design

  • Full Member
  • *
  • Posts: 179
  • UK
  • Liked: 41
  • Likes Given: 51
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #134 on: 03/03/2015 11:51 AM »
UK ministers issue spaceport shortlist:-

http://www.bbc.co.uk/news/science-environment-31711083

Three of the 6 shortlisted sites have runways under 3000m, with implications for Skylon unless rectified.

Offline Star One

  • Senior Member
  • *****
  • Posts: 8257
  • UK
  • Liked: 1336
  • Likes Given: 168
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #135 on: 03/03/2015 11:58 AM »

UK ministers issue spaceport shortlist:-

http://www.bbc.co.uk/news/science-environment-31711083

Three of the 6 shortlisted sites have runways under 3000m, with implications for Skylon unless rectified.

Already a dedicated thread for this.

http://forum.nasaspaceflight.com/index.php?topic=35163

Online john smith 19

  • Senior Member
  • *****
  • Posts: 6182
  • Everyplaceelse
  • Liked: 822
  • Likes Given: 5138
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #136 on: 03/03/2015 12:40 PM »
UK ministers issue spaceport shortlist:-

http://www.bbc.co.uk/news/science-environment-31711083

Three of the 6 shortlisted sites have runways under 3000m, with implications for Skylon unless rectified.
I don't think any of the runways have the necessary 5000m for a full Skylon runway.

Logically Newquay, being at a slightly lower longitude is best if you want direct launch to orbit. Otherwise I think most of then could handle Skylon payload loading and take off in air breathing mode.

OTOH as Hempsell pointed out all UK sites are bad for equatorial launch, but OK for polar launch, which is handy for some kinds of Earth observation missions.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Star One

  • Senior Member
  • *****
  • Posts: 8257
  • UK
  • Liked: 1336
  • Likes Given: 168
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #137 on: 03/03/2015 02:57 PM »

UK ministers issue spaceport shortlist:-

http://www.bbc.co.uk/news/science-environment-31711083

Three of the 6 shortlisted sites have runways under 3000m, with implications for Skylon unless rectified.
I don't think any of the runways have the necessary 5000m for a full Skylon runway.

Logically Newquay, being at a slightly lower longitude is best if you want direct launch to orbit. Otherwise I think most of then could handle Skylon payload loading and take off in air breathing mode.

OTOH as Hempsell pointed out all UK sites are bad for equatorial launch, but OK for polar launch, which is handy for some kinds of Earth observation missions.

This isn't really relative to REL as they didn't even respond to the consultation.

Offline RanulfC

  • Senior Member
  • *****
  • Posts: 4416
  • Heus tu Omnis! Vigilate Hoc!
  • Liked: 770
  • Likes Given: 32
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #138 on: 03/03/2015 07:31 PM »
And just to "tweak" the doubters again, ('cause its fun :) ) I was re-reading "Facing the Heat Barrier" again and found something I'd missed the first couple of time. Seems Lockheed has done some work on a "SABRE-like" engine for a 1962 space plane study with a system called "Tubo-LACE" (which was a misnomer as it didn't even USE LACE)

From “Facing the Heat Barrier” chapter 4, page 119:
“For takeoff, Lockheed expected to use Turbo-LACE. This was a LACE variant that sought again to reduce the inherently hydrogen-rich operation of the basic system. Rather than cool the air until it was liquid, Turbo-Lace chilled it deeply but allowed it to remain gaseous. Being very dense, it could pass through a turbocompressor and reach pressures in the hundreds of psi. This saved hydrogen because less was needed to accomplish this cooling. The Turbo-LACE engines were to operate at chamber pressures of 200 to 250 psi, well below the internal pressure of standard rockets but high enough to produce 300,000 pounds of thrust by using turbocompressed oxygen.”

All under the "Aerospaceplane" study effort that was sponsored by the Air Force looking for an air-breathing launch platform :)

As an additive "thunk" experiment, I was wondering if a modified REL HE could work effectively in reverse? (Using suitable materials of course) Having a "hot" heat exchanger in the place of a normal combustion chamber to provide heating of the air. I recall there was some work done by a small Canadian company on such a design for use with alternative fuels for aircraft engines though I can find nothing at the moment on it. The idea was you could use less than ideal fuels to provide thrust through the HE concept rather than burning the fuels directly in the airstream. Mostly because some fuels (peanut oil IIRC was one suggested fuel) don't burn in a high speed airstream as well as kerosene products, but some mention was made that heating a supersonic airflow (yes getting into my "favorite" engine cycle here the SCramjet :) ) without causing shockwaves due to injected fuel.

Probably impractical but discussions with someone on using an "electric fan fed" jet engine got me to thinking...

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

  • Senior Member
  • *****
  • Posts: 4416
  • Heus tu Omnis! Vigilate Hoc!
  • Liked: 770
  • Likes Given: 32
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #139 on: 03/03/2015 08:31 PM »
Build a heat-shielded jet aircraft lighter than 15 tons or maintain a network of LH2-capable runways in hostile regions, neither seems particularly feasible
Correct.

The CRADA is about specifically about the SABRE engine cycle.

If they'd wanted Hypersonic cruise I'm quite sure they'd have requested more information on the LAPCAT work for M5 cruise.

Put it this way, if they are not looking at SABRE for use in a launch vehicle they are very foolish.  :(

And one thing the US in general and our military specifically is NEVER is foolish by assumption :)

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?

Tags: