ORIGINAL: RICKSTUBBZ

Hey Rich and FastJ,

One thing that is great about these forums is the opportunity to share info.

I know this thread is about a Phoenix Extra 300 and not engines. But I'm throwing in a couple pennys worth of experience here. My Supre Tigre 90 (the real world reference that Rich mentioned) Turns a 14X7 three blade Master Airscrew and a wooden (forgot which brand zinger top flight) 15X6 two blade at about 9,500 static measured with a tack. running 0% nitro. Using a 14X6 two blade the engine turned in the neighborhood of 10,250ish. Been long enough now I don't remember exactly. My 13X6 two blade ran in excess of 11,000 rpm. What I do know is the 14X6 would not pull my 9lb plane with unlimited vertical. With both the 14X7 three blade and the 15X6 two blade the plane will climb vertical forever, albiet slowly. If I am after speed the 13X6 pulled faster flat and level. As to the load I am putting on my engine, again measured static, I used a temp sensor pointed at the glow plug. The smaller props ran between 290°- 310° were as the 15X6-2 and the 14X7-3 run in the 280° - 300° range.

I will not attempt to say what the OS 91 can or can not due since I do not have one. However, I agree that it is a good engine.

After digging out my notes I found that the RPM numbers I wrote above were 1000 RPM too high[:@]. Everything else is/was correct. The RPM are now correct. I'll be re-testing soon with a test stand set up to measure thrust.