|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
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 |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Airplane-like first stage | Pat Flannery | History | 0 | August 14th 09 08:34 AM |
Airplane Scientists | Rand Simberg | Space Science Misc | 37 | December 25th 03 05:54 AM |
Airplane Scientists | Rand Simberg | Policy | 23 | December 25th 03 05:54 AM |
Eclipse and Airplane | macnmotion | Amateur Astronomy | 15 | November 10th 03 08:43 PM |