I am looking to find a sweet spot for about 50HP driving about a 48" prop direct drive. I am guessing that this falls in the right spot for about 5000 RPM for an inline twin that would fit in a compact engine nacelle. The combo would need to deliver about 100 lbs of thrust at somewhere near 300mph. The idea is a pair of say PWC engines. What I know is that the late Lars Giertz was driving a 48" prop with a 100HP AMW engine and designing around near 300mph. I believe he was using a reduction though. There are an abundance of 50HP inline twin engines out there.
I guess I am asking what the best RPM/pitch combo would be near that diameter and airspeed.
I guess I am asking what the best RPM/pitch combo would be near that diameter and airspeed.