The Brits have engineered some amazing propulsion over the years and they have some really cool tech in this engine. It's hard to see how the Skylon vehicle will be able to compete with Spacex on cost.
Hard to imagine what else one could even want a launch system to do (except perhaps to be a nuclear turborocket ala http://www.youtube.com/watch?v=C46Dt-X0V8c , if that were politically feasable). And you can hardly say that of anything SpaceX is doing, given that those are simply incremental improvements of existing rocketry tech.
Presuming they ever manage to make it work (which is prob the big question), it should bring significantly more to cheap launch than SpaceX ever could on their current trajectory.
But anyhow yeah - the physics should favor them by practically an order of magnitude, but if they can ever survive to reap any percentage of that potential - they could just as likely just go bust at any further point in r&d, and they don't seem to have either much funding nor are they advancing particularly rapidly...
Skylon uses that extra efficiency to haul extra components into space. Such as the wings, landing gear etc. Based on the rocket equation it will only have usable payload if the mass of the craft can be kept very low. This would require lots of new technology and materials. Even with a better engine that would be very difficult.
The thing is that all that new technology could also be used by Spacex to improve a conventional rocket. And without the extra mass you would have have much higher payload. And the payload could be used by customers and not wasted on wings.
The best way to use new engine is probably to strap it onto a conventional rocket. Less complex and more payload. And maybe that extra payload could allow second stage reuse. That would make things even more competitive.
I understand the whole point of this is that the rocket equation, assuming as it does that you'll be carrying all the fuel you need with you right from the start, doesn't apply until you get to about 28 km up, and once you get to that point you're not starting from zero speed; you're starting at about mach 5.
Anyway, on the the answer to your question. The projected outcome is that the cost per KG of payload into orbit is less. So that's why. Because it will be cheaper.
So why not use the extra fuel to increase payload or have a reusable second stage? This could reduce costs for conventional launch companies, and make Skylon less viable.
The projections would have to make assumptions about development costs. That seems rather hard to predict with any accuracy. Especially considering how revolutionary every part of the craft would need to be.
> And that first stage could be reusable based on the SpaceX model.
Do you see a contradiction in these statements?
Don't you think SpaceX uses landing gear?.. You see what I mean?
A fully-featured spaceplane is a paradigm-shifter. SpaceX decided not to try because the tech was too far down the line. Novel propulsion takes decades to prove out, and Reaction are working through it reasonably. The sticking point was the hypersonic precooler, and they've cracked that. A whole-engine scale demonstrator should be a relatively straightforward next step.
Basically imagine the entire program development cost of an A-12/SR-71 or X-15, but far more complicated, and re-implemented adjusted for inflation in the year 2020 starting from a clean sheet of paper. Many billions of dollars.
They also gave one example away over a game of billiards.
http://www.tdpri.com/threads/for-aircraft-enthusiast-how-a-g...