The wonder of Skylon is it is an SSTO.I doubtn if Eugene Saenger had a
*commercial* supersonic carrier launch platform in mind in the forties for his
two stage hthl design. Which objective was an intercontinental bomber iirc
albeit with an ssto potential given reentry tiles or Skylon skin.John
------ Origineel bericht------Van: Henry SpencerDatum: za, 1 dec. 2018
22:55Naar: Arocket List;CC: Onderwerp:[AR] Re: Skylon Progress (was Re: Silicon
Carbide)
On Fri, 30 Nov 2018, Rand Simberg wrote:>> What would have been your idea for
"different" ?>> Something based on fundamental research into the nature of
supersonics, > the cause of wave drag and entropy in the wake, and figuring out
what to > do about it...Translation: Rand has been involved with some folks
who've been pursuing such ideas, so that's the only acceptable approach. :-)In
fairness, their ideas *are* very interesting, and if their concept for
essentially shock-free supersonic flight works, it could make a big difference
to aviation. It does seem like something that would be worth at least a modest
amount of high-risk-high-payoff R&D funding.(More precisely, I should say
"shock-free supersonic *lifting* flight". If you read old aerodynamics books,
you find that people noticed the possibility of shock-free supersonic flight a
long time ago. One of the shock-free shapes, the "Busemann biplane", appeared
in the same paper that first proposed swept-back wings. But nobody c
ould find a shape that would produce *lift* without shock waves -- the
Busemann biplane is shock-free only at zero angle of attack -- so the idea
gradually got forgotten.)However, it's not necessarily the *only* way to get
good supersonic L/D. Concorde didn't do too badly, even the traditional
approaches can do significantly better now, and there are other poorly-explored
options, like compression lift.Finally, trying to rein in this digression a
bit, it doesn't seem very relevant to rocketry, or even Skylon. :-) Almost
certainly, a more efficient supersonic aircraft would have to be tightly
optimized for cruise at one specific speed, so this wouldn't be very useful for
"accelerator" missions like space launch. (Except insofar as easy availability
of commercial supersonic aircraft might make air launch more attractive as a
starting point for a rocket.)Henry