It would be interesting to see if something like this could improve efficiency in valveless pulse jets. Valveless pulse jets rely on different inertia in two a

It would be interesting to see if something like this could improve efficiency in valveless pulse jets. Valveless pulse jets rely on different inertia in two air paths to pull fresh air back in one of the exhaust pipes to refill the combustion chamber. Valveless pulse jets are loud and inefficient, but they're reliable, tolerant of manufacturing defects, and cheap to produce. Of course, acoustic effects providing the only compression above ambient pressure is going to fundamentally limit combustion pressures and temperatures, and thereby thermodynamic efficiency, but I think valveless pulse jets operate significantly below their Carnot / Brayton efficiencies.