QuoteHow many suborbital flights happened in the last five years? How many suppliers are in routine operations? I rest my case.They still have preorders. The preorders proof the point. I rest my case!QuoteWrong, it shows a trend.Nonsense! You can not devise a trend from a single data point!QuoteWrong. The costs are unknown. There for the market is also.Nonsense again!
How many suborbital flights happened in the last five years? How many suppliers are in routine operations? I rest my case.
Wrong, it shows a trend.
Wrong. The costs are unknown. There for the market is also.
And yes, it would be great. Skylon holds the promise of dramatically reducing launch costs and opening up space like never before. But it can succeed economically without doing so. The business model doesn't collapse until the total sales drop below about 10, with a pessimistic discount rate.
Preorders are meaningless. They can be canceled.
TU-144, SR-71 and the list goes on
Quote from: 93143 on 11/28/2012 10:50 pmAnd yes, it would be great. Skylon holds the promise of dramatically reducing launch costs and opening up space like never before. But it can succeed economically without doing so. The business model doesn't collapse until the total sales drop below about 10, with a pessimistic discount rate.I love how people already - before any metal has been bent on any flying prototype - still think that they know what the costs would be. Amusing.
Exotic engines aside my concern with Skylon is one of directional stability. All hypersonic vehicles had a lager vertical stabilizer ala X-15 to Shuttle. Skylon looks like an X-3 redo with all its inherent problems. I guess we’ll see the final configuration....http://www.456fis.org/DOUGLAS_X-3.htm
The turbine blades experience enormous centrifugal force loads as well as high thermal loads at 600 revolutions per second. High cycle fatigue and hydrogen embrittlement effects, have caused small hairline cracks in the turbine blades of the high pressure fuel turbopump. These cracks are an order of magnitude shallower than the critical depth of 0.100 inch, but have persisted throughout the program. Although the hairline cracks are not detrimental to performance, periodic disassembly inspection is needed to continue to monitor this condition. Attention is given to blade porosity after machining (5 mil pores). Shot peening of blades on the blade-to-wheel interface improves toughness and resistance to cracking. Gold plating of blade shanks resists hydrogen embrittlement.
I don't understand you guys. I just don't see this project the way you seem to see it.Skylon is about answering this question: "Can a plane fly all the way to orbit, reenter the atmosphere and then land safely?"If the answer to this question is affirmative, then it would be awesome, at least from the perspective of anyone who's interested in technology.Now, can such a plane have commercial use? I don't know. This might be even more complicated that the physics behind the first question. It's a matter that concerns mostly the investors, anyway.It's often like that in technology: you design and build stuff, and sometimes you don't even know if it will be useful. You just want to know if it can be done. For the rest, you'll see later.
Is Skylon technical awesome? Yes.So awesome the experiment may be worth £100,000,000.If you want more money than that it has to make a profit.
Actually, if SABRE works as planned, governments may decree that it replace conventional fossil fuel engines on airliners in order to cut down on CO2 emissions. In that case it would make a profit by government decree. There seems to be a high likelihood of this happening considering the deteriorating state of the environment. It's a straightforward fix for the pollution from airliners.
Not kidding. I expect there to be a long series of government decrees which radically change the way business operates in the future. You've only seen the tip of the iceberg (CO2 fees on European passengers are just the opening salvo from governments).Besides, REL and the UK Science Minister have already spoken to the topic of SABRE in aviation, so it isn't out of the question that a new design for airliners using hydrogen/air engines would be put into operation in the future simply because it makes sense from a pollution perspective.
One of the major drawbacks to the SSME was the fact that it had to be disassembled and examined after every flight.I have not found any reference to these kinds of problems/solutions on the REL website. This could be a show-stopper for the reusability of the SABRE engine.
You're kidding, right? SABRE is much too different from conventional engines. It works on hydrogen, for once. Governments might as well try to force airliners to switch to electric propulsion. That's way too much to ask.
QuoteYou're kidding, right? SABRE is much too different from conventional engines. It works on hydrogen, for once. Governments might as well try to force airliners to switch to electric propulsion. That's way too much to ask. That, and hydrogen is way, way harder to handle than plain old kerosene. It is not a magical fuel; airports won't switch from kerosene to hydrogene easily. It is very low density, very low temperature, small concentration of gaseous hydrogen in the air goes KABOOM, and, final nail in the coffin: it can't even be stored into the aircraft wings, like kerosene is. Hydrogen is so cumbersome to store when compared to kerosene that the drawbacks negates the higher energy it contains. Just saying... Skylon uses hydrogen a) because it needs it to go intoorbit and cool the air and b) because it will never take-off from conventional airports...
