Video: Alan Bond of Reaction Engines on Skylon Development
An interview with Alan Bond at Reaction Engines on the Skylon single-stage-to-orbit vehicle.
11 responses to “Video: Alan Bond of Reaction Engines on Skylon Development”
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I’d like to think his analysis of the lack of British vested interest in space as a benefit is correct. Looking at the current state of the SLS in the states and massive amounts of senate meddling and Russia’s woes I think he could be right.
Thank you for that one! It’s my favourite approach…
He actually sounds very sane. I’ve gone from about 10% to about 40%, on this presentation alone. And that’s a very interesting point he made at the end: through an odd historical twist of fate, the British have been left with little or no vested interest in perpetuating expendables.
The de-icing problem, hmm. He speaks of being able to do it sustainably, so I suppose it can’t be anything like antifreeze. I wonder if they’ve found some way to take the water vapor consumed while accelerating and heading out of the atmosphere and make it a source of the water they’d need later for reentry cooling. Perhaps by vibrating the helium-based cooler to keep shaking ice off, while spinning the cooler to fling the ice out to a heated cylindrical surface, from which it gets drained. In the part about reentry thermal management, he makes a very odd comment about “remembering” to top up with coolant water before take-off; that might be just a red herring, and a deadpan in-joke.
I’ve no doubt the design closes in all the analysis he mentions, but paper airplanes have been flying SSTO since 1983. When you’re subtracting two numbers of nearly equal magnitude (thrust and drag), any uncertainty or error in the estimates gets magnified. It becomes very easy to fool yourself and others.
I guess it would be quite a safe bet to say that, given full funding, Skylon will be in operation before the ominous Ariane 5 replacement that is expected to take 15 years to develop.
GENIUS.
jstults, the Skylon people have been working on this for several decades, and they predict another decade of work to get a vehicle even if they got fully funded tomorrow. If they had made such an elementary numerical analysis error, I think somebody would have caught it by now. The showstopper here is far more likely to be something unforeseen. Of course, it could be that they *know* they don’t have the basis for an orbiter, and are only using the space-access angle as publicity, hoping to cash out on a revived SST program at least. Maybe. But it’s the kind of thing that’s hard to keep secret for so long.
ESA reviewed the Skylon design, so we know it’s not a scam.
Or we know it’s not an easily-debunked scam, anyway. There are certainly a few fuzzy areas in the ESA report.
http://www.bis.gov.uk/asset…
“For the SABRE engine cycle analysis the issues identified were the result of an investigation by an ESA sponsored PhD at the Von Karman Institute (RD13). One of the limitations of this analysis by VKI is that the majority of the engine data is
obtained from the final report of the SABRE engine for FESTIP, delivered to VKI by
Reaction Engines in 1997.”
The ESA’s conclusion is “plausible,” which is not the greenest of green lights. It recommends performing more independent simulations.
Much might depend on whether the UK will be willing to subsidize SST work again, so soon after the Concorde’s mothballing. Is that really a viable human transportation market? 25 years off might as well be “never”, if you can’t make money.
But then there are the cost-no-object goals. Alan Bond speaks ambiguously of “applications” for supersonic transport. Military operational responsiveness (short of orbital delivery) could be one of them. If an early version of Skylon could go to the edge of space, going at even half of LEO velocity, then (in near vacuum) eject a second stage that wouldn’t need to be aerodynamic (thus saving mass), maybe that could give you a lot of quick-draw spysat capability.
I don’t think it’s a scam. I think these system analyses are at a high level of abstraction, and the empircal constraints are weak because of the paucity of even ground test data. A few assumptions nudged slightly in the right direction adds up to a design that closes. Nothing nefarious, each assumption is defensible in isolation, but they’ll all tend in the right direction to give the needed answer once things are all rolled up. Oh btw, predicting drag is a really hard problem, and this concept involves sticking lots of extra equipment in the flowpath which is now a multi-phase mess with all sorts of secondary loss mechanisms that probably aren’t included in the conceptual-level analysis.
I won’t be holding my breath on airbreathers to orbit. They’re like fusion: always decades away.
Michael Turner, thanks for linking that report.
This doesn’t sound like the path to “aircraft-like” ops to me: The Aeroshell is expected to be made up of 300mm x 300mm CSiC panels, having a low thermal conductivity, attached to flexible mounting structure to allow for thermal expansion during re-entry.
There’s a neat historical connection to the DynaSoar approach here though. They had Columbium and Molybdenum “shingles” instead of Skylon’s CarbonSiC tiles mounted on a flexible nickel supper-alloy structure. Dyna-Soar used radiatively-cooled hot structure, with the primary or load-bearing structure being of Rene 41. Trusses formed the primary structure of the wings and fuselage, with many of their beams meeting at joints that were pinned rather than welded. Thermal gradients, imposing differential expansion on separate beams, caused these members to rotate at the pins. This accomodated the gradients without imposing thermal stress.
Facing the Heat Barrier: A History of Hypersonics