Im considering various gas and glow engines for a 13 lb. racer. Recommended glow engines are between 1.60 and 2.10 c.i. and gassers are recommended between 26 and 35 cc. I know for high speed you want high pitch and high rpm. Ive read that alot of people have used 15x12 and 16x10 props for this setup and peak rpm is around 9000 rpm. Assuming the aerodynamics are good, what kind of rpm do I need to get to reach speeds of 120 mph+? Will engines these size turn 10000 rpm? or more?

Very approximately a 14" pitch at 10K for 120mph.

Ed S

I've been reading the section on posting your tach readings and I think a gas 26cc only puts out the power of a glow 1.40. If this is the case you will get much more speed out of a 2.10 glow engine. I was thinking about getting a gas spe 26cc to replace my unreliable ST2300 and to me it looked like it was just not comparable especially when you account for the extra weight of the gas set up.


Are we talking H9 Sundowner here, if so I bet the mark M 2.10 would be the engine of choice? But your glow fuel bill will be a little painful.

yes, its the sundowner. I dont like the idea of using gas because of the extra pound of weight that comes along with the engine, but youre definitely right about the fuel bill.