btw I don’t think it’s an obscure subject. Soon you probably won’t either.

Well. We’ll know in the next couple of weeks. As things stand, if they have proven the cooler during these tests, “someone” has 250 million for them to build and test the engine which I believe is a 3 year project to completion (3 years of the 10 year project for the whole vehicle), so a complete answer to your scepticism is only 3 years away, not 50 – or 100.

And no, I don’t selectively read, thanks for asking.

“Reaction Engines are about to complete an ESA funded study and announce whether the cooling works or not in the next few weeks.”

Reaction Engines is made up of former British Aerospace and Rolls Royce experts in their field. ESA are not funding this full scaler cooler test because they think Reaction Engines are making a scramjet or anything else that isn’t true.

Reaction engines was foudned by former British Aerospace and Rolls Royce experts in their fields. I think ESA are thinking it is a smaller “if” than you are attempting to claim – and so am I. The cooler really IS the magic ingredient that makes the difference that they have been working on for 30 years.

That’s a pretty big ‘if’ though. You and Hentzau pretty much agree on this point, don’t you? I’m not sure what your issue is.

See my above reply for a more reasoned critique of why I think Skylon has some issues; we agree that cooling the air is the tricky part and when I see the precooler fly as part of the Sabre engine I’ll accept Skylon can work. Till then, I don’t believe it can be done outside of a laboratory. It’s difficult to predict technological progress, and there’s nothing wrong with the Skylon *concept*, physically, it just requires you to do something that I think is somewhat beyond modern technology. In fifty or a hundred years, maybe, but not now.

This is from wikipedia about Alan Bond, the founder, Managing Director and Chief Technical Analyst at Reaction Engines:

“He worked on liquid rocket engines, principally the RZ2 (liquid oxygen / kerosene) and the RZ20 (liquid oxygen / liquid hydrogen) at Rolls Royce under the tutelage of Val Cleaver, and he was also involved with flight trials of the Blue Streak at Woomera.

He then worked for about 20 years at UK Atomic Energy Authority’s Culham Laboratory on nuclear fusion, on the JET and RFX nuclear research projects. He was engaged in studies for the application of fusion to interplanetary space travel. He is the leading author of the report on the Project Daedalus interstellar, fusion powered starship, published by the British Interplanetary Society.

In the 1980s, he was one of the creators of the HOTOL spaceplane project, along with Dr. Bob Parkinson of British Aerospace. Alan Bond brought a Liquid Air Cooled Engine design he had invented to the HOTOL project, and this became the Rolls Royce RB545 rocket engine.

In 1989, he formed Reaction Engines Ltd[1] with…..”

http://en.wikipedia.org/wiki/Alan_Bond_%28rocket_developer%29

And the pre-cooler, man. I do not claim to have any detailed knowledge of Skylon, but I do know about laboratories and the law of thermodynamics. The internet tells me they’ve built a working pre-cooler *in a laboratory*. Perhaps the internet is out of date, and the project has moved past that point, but if there is one thing I learned during my research it is that things tend to work *very* differently in laboratories than they do in their intended real-world environment. Sorry to bring up the scramjets again, but that X-43A NASA built? That is, to me, a practical proof of concept: doesn’t do anything directly useful but demonstrates that scramjet technology can work as designed in the environment that it’s designed for. It may be possible to use the pre-cooler to remove that much heat from the air in a laboratory, but as far as I’m concerned that’s not the same thing as a practical demonstration that Skylon can work as designed.

(As a cruder example, we’ve known about the principles governing railguns and even had working laboratory examples to investigate hypervelocity impact physics for nearly half a century, yet I’m not seeing the latest and greatest naval vessels mounting railgun tech any time soon.)

So yes, I’ll continue to be skeptical. If in twenty years time we’re all flying into space on board Skylon spacecraft you can, if you remember this conversation, come back here and say “I told you so!” Until then — or at least, until I see a working example of the Sabre engine flying — I’m going to maintain my position that Skylon cannot work.