The cruelest lies are often told in silence. -Robert Louis Stevenson



A pulse detonation engine or pulse jet works like any other combustion engine. Compress Air, with fuel, detonate, expand and repeat. The a pulse jet is much simpler mechanically than a typical piston engine or a turbojet. ]



A pulse jet engine has only one moving part, a simple leaf valve.



As the air moves through the intake and past the fuel line the low pressure draws in fuel and mixes it with the air.



The fuel/air mixture passes the open valve and enters the chamber. A continuous spark detonates the mixture. The high pressure acts to both close the valve and expel hot gasses out of the chamber creating thrust. As the detonation wave leaves the chamber it creates low pressure which opens the valve and draws in air, thus continuing the cycle.



We have several small pulsejets. The video below shows a firing at night. It is a simple steel chamber with thin spring steel valves at the front. We are using white gasoline (gas without the additives AKA Coleman Fuel) for fuel. You can see that the chamber gets quite hot. The exhaust gasses aren't too hot, you can put your hand in them and it is just warm. One neat thing to do is to look up the pulsejet from the rear (using eye or preferably face protection just in case a valve lets loose). You can see all the way to the combustion chamber. You will need ear protection to run one of these, they are incredibly loud. The video was recorded far away from the pulsejet because the sound was causing problems with the digital camera. God I love this video.




We also have a 1/2 scale V-1 engine which I created a separate page for.