Pulse detonation engine

Key issues for further development include fast and efficient mixing of the fuel and oxidizer, the prevention of autoignition, and integration with an inlet and nozzle.

[3] The first known flight of an aircraft powered by a pulse detonation engine took place at the Mojave Air & Space Port on 31 January 2008.

[5] The engine consisted of four tubes producing pulse detonations at a frequency of 80 Hz, creating up to 200 pounds of thrust (890 newtons).

A small rocket system was used to facilitate the liftoff of the Long-EZ, but the PDE operated under its own power for 10 seconds at an altitude of approximately 100 feet (30 m).

[6] In June 2008, the Defense Advanced Research Projects Agency (DARPA) unveiled Blackswift, which was intended to use this technology to reach speeds of up to Mach 6.

In many cases some of the charge is ejected before burning, which causes the famous trail of flame seen on the V-1 flying bomb and other pulse jets.

[citation needed] Key difficulties in pulse detonation engines are achieving DDT without requiring a tube long enough to make it impractical and drag-imposing on the aircraft (adding a U-bend into the tube extinguishes the detonation wave); reducing the noise (often described as sounding like a jackhammer); and damping the severe vibration caused by the operation of the engine.

[citation needed] If both fuel and oxidizer are carried by the vehicle a pulse detonation engine is independent of the atmosphere and it can be used in spaceflight.