Aircraft engine
Pulsejets

Pulsejets are mechanically simple devices that—in a repeating cycle—draw air through a no-return valve at the front of the engine into a combustion chamber and ignite it. The combustion forces the exhaust gases out the back of the engine. It produces power as a series of pulses rather than as a steady output, hence the name. The only application of this type of engine was the German unmanned V1 flying bomb of World War II. Though the same engines were also used experimentally for ersatz fighter aircraft, the extremely loud noise generated by the engines caused mechanical damage to the airframe that was sufficient to make the idea unworkable.
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