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.
Blunt-body reentry with high gees and ablative shielding add less mass than wings would.
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.
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.
Quote from: momerathe on 06/20/2016 10:48 amQuote from: Nilof on 06/20/2016 10:26 amYou 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.
Quote from: Nilof on 06/20/2016 10:26 amYou 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.
You do NOT need wings or lifting bodies at all for reuse.
Quote from: momerathe on 06/20/2016 10:48 amQuoteI 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.
QuoteI 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?
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.
Opinion | Reviving The Aerospace Plane Programhttp://spacenews.com/reviving-the-aerospace-plane-program/
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!)
BAE Systems have released a video of a single-engined Mach 5 vehicle which is clearly SABRE-derived:
Quote from: SICA Design on 07/04/2016 11:04 amBAE 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 publicI 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.
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...
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 ?.