"Everyman's Jet Engine" - Why Valveless Pulsejets? Immediately ready to run after being completely flooded with water A classic experiment showed that a valveless pulsejet could be completely flooded by immersion in water, then quickly drained and immediately started and brought up to a full-power run. Try that with any other type of jet engine ever designed! Even a conventional valved pulsejet will fail this test, because the water seizes up the reed valves against the face of the valve head until the engine has been disassembled and carefully dried.