July 20th, 2010 at 10:15 AM ^

Both the X-43 and X-51 are testbeds for "scramjet" (Supersonic Combustion Ramjet) technology. The difference between the X-43 and X-51is that the X-51 was designed to test a scramjet with a relatively long burn time (up to 300 seconds, if it works out). The X-43, which was primarily a test to see if they could get a scramjet to fly at all, had a maximum 12 second burn time.


July 20th, 2010 at 10:30 AM ^

That's right, there's basically nothing that moves other than the fuel itself. That's why they need a booster rocket to get them moving fast enough to ignite. A ramjet operates under the same principle. This difference is that, in a ramjet, shock waves in the inlet slow the airflow down to subsonic velocities in the combustion chamber. In a scramjet, the airflow is still supersonic in the combustion chamber. It is extremely difficult to keep a flame burning at supersonic speeds, which is why these things are still in a very experimental stage.


July 20th, 2010 at 7:27 AM ^

A 14 foot long, angular, "shark-shaped" craft with no wings to speak of traveling Mach 5... Yeah, that's not going to prompt dozens of calls to local TV stations about aliens every time it flies.

I believe this just proves that the Air Force really gets off on messing with the foil hat crowd.


July 20th, 2010 at 9:55 AM ^

The company I work for is also on the super/hypersonic bandwagon, having also just launched a craft that flew 110 miles at mach 3.3 and executed a dive.  Their whole purpose is to serve as target vehicles for the military out over the Pacific.  Exciting stuff - hopefully it finds its way into commercial air transportation sometime in our lifetimes!