"Everyman's Jet Engine" - Why Valveless Pulsejets? Reasonable throttleability Several experimentors, with several different engine designs, have been able to show that modern valveless pulsejets are capable of being throttled down to very low power levels (sometimes even to such a low noise level that shouting is audible!). This requires very accurate acoustic tuning, in order to maintain resonance at such a low power setting. The idea that pulsejets, and especially valveless pulsejets, are incapable of low-level running is nothing more than a persistent myth. This belief may be due to so many engines being built that will run but that are not really fully tuned.