Ernie,

No problems balancing the airplane at all with the ys 45, here are the specs on the 45 from the http://www.ysperformance.com/ web site:

RPM Range: 2,000 to 18,000 RPM
Prop Sizes: 9 X 8 to 11 X 7
Weight: 14.2 oz.
1.5 hp with stock pipe (per e-mail from ys performance)

I'm guessing this is the weight without muffler, as they didn't come with one. The ys manual says the engine was designed for a tuned pipe.

OS 46 FX specs from OS http://www.osengines.com/engines/fx.html

46 FX
(2,000-17,000
1.59hp @ 16,000
13.2 OZ
10.5x6, 11x6-7, 12x6-7

I'm also guessing that this is without the muffler. And as you can see the specs are real close, but both were in the air on Sunday and the YS was clearly stronger, a comment from the guy who had the OS 46.

In short, the YS makes up for what little extra weight you carry, it is a very strong engine.

WOOD