Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 442310 times)

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1600 on: 06/21/2016 06:36 AM »
You do NOT need wings or lifting bodies at all for reuse. Winged reentries are the root of all evil. Reducing peak g-loads and peak heating seems like a good trade at first, but it moves the heating problem to a near-equilibrium heating situation which forces you into a lot of bad trades that tend to increase shielding mass. Wings add mass, are useless for most of the flight, and add reentry problems that are arguably harder than the ones they solve.
You seem to have a  design in mind. Perhaps you should move this discussion to a new thread?
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Blunt-body reentry with high gees and ablative shielding add less mass than wings would.
As Dyansoar and Hermes "proved."  :(

Yet the USAF has persisted with the X37b, whose wings are used only during descent.
As always in such a discussion such a statement has so many hidden assumptions behind it that it's virtually meaningless.
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Lift is naturally much easier to get at high gees so maintaining the maximum load at the design level is easier. Any structural reinforcements required also give you more safety margin on the way up.
Don't you mean high velocity?
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I would argue that three different wingless vehicles are much easier to design than a single winged vehicle that has to work from mach 0 to mach 25.
BTW After Mercury (which was designed for a pure ballistic entry) all US vehicles have generated aerodynamic lift as part of their trajectory.
"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 momerathe

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1601 on: 06/21/2016 10:51 AM »
You do NOT need wings or lifting bodies at all for reuse.

No, but it cuts the required takeoff thrust by your L/D ratio. IIRC the SABRE thrust in airbreathing mode isn't enough for vertical takeoff, without scaling the engine up considerably.

But for TSTOs it gives you nothing. Liftoff T/W barely cuts into the dry mass that has to be brought with you into orbit at all.

Why don't rockets have turbofan first stages, then? they've got great ISP..

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I would argue that three different wingless vehicles are much easier to design than a single winged vehicle that has to work from mach 0 to mach 25.

Well yes, that's obvious. Is that actually what AFRL are proposing though?

It is what the USAF will likely be contracting for standard workhorse launches in a few years, without any government R&D money required.

What's that got to do with anything? I'll restate the question. Are AFRL proposing a SABRE-based, wingless, VTVL TSTO?

« Last Edit: 06/21/2016 10:52 AM by momerathe »
thermodynamics will get you in the end

Offline Star One

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1602 on: 06/23/2016 05:47 PM »
Opinion | Reviving The Aerospace Plane Program

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The design of an aerospace plane strongly depends on the propulsion system. With successful ground and flight tests of the SABRE, it could be available for use in an aerospace plane in the 2020s, decades before the availability of appropriate turbine-based combined cycle (TBCC) engines [which are designed either with a turbine engine plus a dual-mode ramjet (or dual-mode scramjet) engine] for an accelerating atmospheric flight reaching Mach ~11. The USAF hypersonic roadmap projects technology readiness in the 2040s for a hypersonic cruise aircraft using a TBCC engine. Consequently, the first-generation operational aerospace planes would use SABRE and the second-generation planes would use TBCC engines.

http://spacenews.com/reviving-the-aerospace-plane-program/

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1603 on: 06/23/2016 07:21 PM »
Opinion | Reviving The Aerospace Plane Program
http://spacenews.com/reviving-the-aerospace-plane-program/
Read it. If you know the subject it's hilarious.  :)

Either this guy is an associate professor or he's with AIAA. You're not a professor with AIAA.



"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 Archibald

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1604 on: 07/01/2016 03:19 PM »
This is certainly sloppy. What aerospaceplane ? the one of the 60's ? the NASP of the 80's ? something else ? Skylon ? (there is a picture of Skylon, but nothing related in the writting)

It looks like someone having an epiphany and saying " hey, we need a RLV to make space transportation cheaper" That opinion is just 70 years old (and counting !)

(P.S is it just me or every single post in this thread related to Brexit have been cut, a complete week of messages ?!!  :o )
« Last Edit: 07/01/2016 03:21 PM by Archibald »

Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1605 on: 07/04/2016 11:04 AM »
BAE Systems have released a video of a single-engined Mach 5 vehicle which is clearly SABRE-derived:



Offline adrianwyard

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1606 on: 07/04/2016 12:12 PM »
Thanks for posting. I wonder who the intended audience is... As you say, it's clearly influenced by Skylon/SABRE, but I wonder if that influence is simply artistic/aesthetic.

(And I certainly hope we don't have to wait for those holographic projection screens to be developed before seeing some flying REL hardware!)

Offline Star One

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1607 on: 07/04/2016 12:17 PM »
Thanks for posting. I wonder who the intended audience is... As you say, it's clearly influenced by Skylon/SABRE, but I wonder if that influence is simply artistic/aesthetic.

(And I certainly hope we don't have to wait for those holographic projection screens to be developed before seeing some flying REL hardware!)

I imagine the intended audience is the USAF.

Offline Hankelow8

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1608 on: 07/04/2016 12:32 PM »
I think this is the first stage of BAC starting to market the SABRE concept, they are big into military hardware on both sides of the "pond".

Sadly that is the reason they acquired shares in Reaction Engines for military purposes only (for the moment ),
it does mean. I think Skylon is anchored up a backwater for the present time, but I do have high hopes it will come good sometime in the next 10/20 years.

Online Alpha_Centauri

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1609 on: 07/04/2016 01:41 PM »
For Skylon to ever have any chance of literally taking off the cost to the investor needs to be reduced substantially. That means the engine development would need to be largely complete and there would need to be an industrial chain in place for the construction of hypersonic vehicles.

If it takes USAF funds to achieve that then I'm not going to complain.

Offline t43562

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1610 on: 07/04/2016 01:44 PM »
BAE Systems have released a video of a single-engined Mach 5 vehicle which is clearly SABRE-derived:

I remember  Alan Bond talking about some sort of military consulting or other work, quite some time ago) and when asked more, he said something like:  "well  you know - it's always about small pointy things zooming around"  or words to that effect.

I suspect this is only new news to the public

I watched that film recently about the US ambassador/representative to Libya. One can imagine how useful it would have been for them to receive reconnaissance/other support very quickly.

Offline Star One

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1611 on: 07/04/2016 03:48 PM »
This article gives some context to the above video from BAe.

http://www.janes.com/article/61966/bae-systems-reveals-advanced-r-d-concepts

Offline Hankelow8

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1612 on: 07/04/2016 05:24 PM »
If BAC do intend to use SABRE as shown in the video as an atmospheric vehicle , I was under the impression LAPCAT was the design best  suited to this form of flight, is SABRE capable of prolonged flight in the
 atmosphere ?.
« Last Edit: 07/04/2016 05:39 PM by Hankelow8 »

Offline dror

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1613 on: 07/04/2016 05:42 PM »
Thanks for posting. I wonder who the intended audience is... As you say, it's clearly influenced by Skylon/SABRE, but I wonder if that influence is simply artistic/aesthetic.

(And I certainly hope we don't have to wait for those holographic projection screens to be developed before seeing some flying REL hardware!)

Seems like a possible XS1 contender.
 ???
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Offline Archibald

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1614 on: 07/04/2016 05:43 PM »
That video, well... it screams "THUNDERBIRDS ARE GO !!!"

Also, (at 0:18 in the video) it looks strikingly like those old ramjet-powered Leduc birds of the 50's, particularly the 021
« Last Edit: 07/04/2016 05:46 PM by Archibald »

Offline knowles2

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1615 on: 07/04/2016 07:13 PM »
BAE Systems have released a video of a single-engined Mach 5 vehicle which is clearly SABRE-derived:

I remember  Alan Bond talking about some sort of military consulting or other work, quite some time ago) and when asked more, he said something like:  "well  you know - it's always about small pointy things zooming around"  or words to that effect.

I suspect this is only new news to the public

I watched that film recently about the US ambassador/representative to Libya. One can imagine how useful it would have been for them to receive reconnaissance/other support very quickly.
They refuse flat out discussed the work Reaction Engines have undertaken for the MOD, only saying they done work for the MOD.
I'm presuming this will use Reaction Engine work in Lapcat than it work into Sabre and Skylon.  Although BAE might want to get a working engine that runs on the ground first before pursuing any real projects that involves using Reaction Engine technologies.
« Last Edit: 07/04/2016 07:18 PM by knowles2 »

Offline Asteroza

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1616 on: 07/05/2016 12:59 AM »
I wonder if that might be a backdoor war to fund the nacelle test vehicle? In the same vein as other marginally militarily useful vehicles like the X-37...

Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1617 on: 07/05/2016 04:36 AM »
I wonder if that might be a backdoor war to fund the nacelle test vehicle? In the same vein as other marginally militarily useful vehicles like the X-37...
I hope that was a Freudian slip! We don't need any more wars to achieve political aims.

That said, the original proposed NTV had identical twin-engine configuration as Skylon, just with a shorter Sears-Haack body. I'm not sure how useful the BAE configuration would be for testing either the nacelle nor SABRE, given the stated purpose of Mach 5 "rapid response" cruise, not orbital launch.

Offline momerathe

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1618 on: 07/05/2016 07:28 AM »
Good point. Can anyone think what the implications of having the intake and the engine much more widely separated would be? (It's probably just brochure-ware, but still)

Would you put the pre-cooler at the front or the back? and would you just be getting back to the centre-of-mass problems that Hotol had?
thermodynamics will get you in the end

Offline STS-200

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1619 on: 07/05/2016 12:16 PM »
If BAC do intend to use SABRE as shown in the video as an atmospheric vehicle , I was under the impression LAPCAT was the design best  suited to this form of flight, is SABRE capable of prolonged flight in the
 atmosphere ?.

REL are developing SABRE as a booster engine not a sustainer, however they don't say this is SABRE (the article only says "along the lines of"). At Mach 5-6, I can't see why they would want any of the rocket engine aspects of SABRE.

Nitpick - they haven't been called BAC since 1977.
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