| 1) jet engines are interesting because of the continuous flow and also that all the rotating parts rotate in the same direction, a huge advantage over reciprocating engines. So jet engines can do 50,000 rps, while piston under 20,000 rps. Note that sleeve piston engines like the Rolls Royce Crecy, are much more efficient than valves, but development stopped at the end of WW2 and resources focused on jet engines. Rolls Royce Crecy - The Most Advanced Piston Aero Engine Never Made https://www.youtube.com/watch?v=cxK_zWgw6gY 2) the exception to continuous flow is the WW2 V-1 pulsejet engine, which has a gate that is closed at combustion time, about 42 Hz. The pulsejet is a very interesting engine in that it's the simplest possible jet engine - literally an empty metal tube with spray nozzles and a sparkplug. The V-1 was the first mass-produced cruise missile. The Germans also had air-to-ground (anti-ship) guided missiles both wire-guided and radio-guided with a TV screen(!) But the US Navy was the first to build precision-guided autonomous missiles, both the all-analog Sidewinder and Wall-eye, which shared modules. The Wall-eye made the famous Gulf War photos you've seen of entering via windows. It had analog circuitry to do edge-detection in real-time. |