ORIGINAL: MinnFlyer
The 61SF is also excellent, but avoid the FP. That is a bushing engine and doesn't have the power of a ball bearing engine.
Now if you really want a great combo, try the H-9 Hellcat with an OS 91 4-stroke [sm=thumbup.gif]
ORIGINAL: MATADOR_24
I think I am gonna stay in the 60 sizes...
The Hanger 9 Hellcat is a 60 sized plane.
A 91 four stroke is the "same" power as a 61 two stroke.
My bet is if you try the 91 four stroke you won't go back to two stroke engines.
Even though four strokes are more expensive, I think they are worth it.