Airplane-like first stage

David Spain wrote:
So back to the subject of this thread.
Let's discuss launching the D-21 at supersonic speeds.

I was thinking this over a bit and it sounds like a fairly complicated
maneuver. It seems like a bad idea to me to just jettison the thing
unpowered and uncontrolled off the back of a Blackbird. Also you've
got to deal with the bow shock wave from the Blackbird itself. If
you're going to power-up the ramjet it seems that it needs to already
be in a supersonic flow in order for the spike to work (all photos
I've seen of a D21 have the famous aerospike in front of the ramjet
in order to control inlet flow to allow the sonic shock wave
to occur inside the engine inlet ahead of the combustor). That means you
needed to start the D21 while it was still attached to the Blackbird
and in the supersonic flow. If you waited until the drone was ejected
outside the supersonic flow its unclear you would be able to ignite
the ramjet. So the D-21's engine must have been started while still
attached and then brought up to thrust to match or exceed that of
the Blackbird mothership before it could be safely detached. I would
suspect that the maneuver for the mothership after detach would be
a slow descent to both allow the drone to safely pass out of the
motherbird's shock cone as well as to form its own. That sounds
really tricky to me and seems like the crux of what Derek is
referring to. You'd have this issue for any staged supersonic
vehicle and you have it in spades when both vehicles have to
stay aerodynamically stable.

The story of launching the D-21 off the M-21:
http://www.spyflight.co.uk/d21.htm
The original plan was to use jettisonable covers over the nose intake
and exhaust nozzle of the drone and jettison then them just before
launch, but on the first test of jettisoning the front one the debris
from it tore the hell out of the chines on either side of the ramjet
intake:
http://www.staynehoff.net/d-21_1st_l...mar05-1966.jpg

Pat