Scramjet tested again

[Bruno Ogorelec]

From a newsletter I subscribe to:

Powered by a supersonic combustible ramjet (and an equally powerful media machine) NASA is turning the spotlight back on itself on Monday. After a brief (and perhaps unaccustomed) period in the shadows of the Paul Allen / Burt Rutan / SpaceShipOne show, NASA will grab some limelight this week by trying to make an "airplane" go faster than ever before.

The X-43A unmanned scramjet will try to hit Mach 10 over the Pacific Ocean off California today. Launch will be about 2 p.m. PST. The X-43 hit Mach 6.83 in a flight last March, setting an all-time aircraft speed record.

Crews loaded the drone under the wing of a B-52 on Thursday, did all the systems checks on Friday and Saturday and fueled everything on Sunday. Because the ramjet engine won't fire unless the plane is already going really fast, it must be dropped from the Buff, and then a Pegasus rocket gives it the needed boost. Wonder how Rutan would do it ...

[Mark]

Mach 10, they will certainly have some challenges with the "meteor effect." How fast do those missiles being tested for missile defense go? Or in other words what's the fastest rocket speed in atmospheric conditions? How would the scramjet compare?
Mark

[Mark]

Just caught a clip of it on CNN. It's dropped from 100,000 feet and is hoping to reach 7000 mph I think they said.
Mark

[wilson]

Sadly the interesting stuff like that isnt televised here, but damn thats fast.
at what altitude do ramjets funtion best?

[Bruno Ogorelec]

Sadly the interesting stuff like that isnt televised here, but damn thats fast.
at what altitude do ramjets funtion best?

Damned if I know. Must be some trade-off between the positive side of air density (to give denser charge) and the negative side (drag).

Must be pretty high, though, as the compression in that engine is vast -- air gets almost solid in the compression zone -- so that it probably works well enough even in very rarified air.

It's a scary kind of machine.

[Mike Kirney]

I read about this on the BBC website. Very exciting! I suppose being way up high in the thin air would relieve some of the effects of the 'meteor effect' because fewer atoms would be making fricitonal contact with the skin of the craft.