"Henry Spencer" wrote in message
...
In article .com,
If you're using two stages, whether you try to make the lower one look
like an aircraft doesn't matter too much, except that it's much more
expensive that way. Building a big Mach 5 rocket is a whole lot easier
than building a big Mach 5 aircraft. (To date, *nobody* has built an
aircraft that could get to Mach 5 entirely under its own power. The first
Mach 5 rocket flew in 1942.)

Indeed, Mach 5 rockets are now within the realm of amateur rocketry, for
certain stretchy definitions of 'amateur.' Consider the Civilian Space
Exploration Team, for instance.
http://www.civilianspace.com/news/maxalt.pdf

It says a lot about the state of hypersonic airbreathing propulsion that
when the X-43 was boosted from Mach 0.8 to Mach 10 by a rocket, and then
managed to briefly not slow down using a scramjet, this was considered a
landmark accomplishment for the scramjet, and utterly unremarkable for the
rocket.

Josh Hopkins