Recently boom supersonic, the supersonic jet airliner startup, released a challenge. Make a supersonic RC plane, and get $800k. There is no chance whatsoever that I’ll be able to do this by manufacturing my own jet engine, and trying to win the competition with the RC jet engines designed for operation around mach ~0.7 seems an expensive and dubious proposition.
There is such a thing as a jet engine where the compressor is powered by an electric motor, here’s a video of one. However everything I’ve seen suggests that the compressor power required is just implausibly high, a minimum of 10’s of kW for a pulse jet with a 150mm diameter.
But. Pulse jets operate well at low speeds but not at high speeds. Ram jets operate well at high speeds but not at low speeds. Both devices are a tube with no moving parts. Could they be combined to get a device that can go from 0 → Mach 1?.
Pulse jet → ram jet.
The various deep research products have gotten pretty good, and so I’ve found quite a few old and poor-quality pdf’s that have suggested such a thing. The most promising one I came across had this extremely intriguing plot:
The Pulsejet Engine - A Review of Its Development Potential (page 42)
Unfortunately, the original source for this is a german article not available on the internet, the only reference I could find was here. But, when I emailed, the very kind people in the archives department scanned and sent me the article!
I’ve had claude translate it to english here.