I have the ST .90 with a Saito 125. It's a good Power to weight compromise. It will pull straight-up out of a hover, but it's not a rocket.

The OS 120 is a bit heavier, I think. You might try experimenting with props before you buy a new engine. BUT...if you buy a new engine, don't compromise. Get the best engine you can afford.

I have 13 gallons through this plane...on my second engine now. You'll love it with more power.


OH YEAH....and don't confuse RPM with power.