If I may suggest an OS 1.20 AX. I have three of them and they DO perform, fit in the footprint of the 90 sized engines and have much more power, easy to start, and run great. And, the price is right.

Two of them are on pattern planes, Excelleron 90 and Veuns II, and the other is on a Goldberg Tiger 120. I prop all of them with an APC 15-10, get about 9800 - 10,000 RPM on a good day.

I had an Evo 100 on the Excelleron 90 but had nothing but problems with it. So, I switched over to the OS 1.20 AX and my problems went away. All the planes have pretty much unlimited vertical and will knife edge with the best of them. Break-in was simple. Three tanks on the ground, first one very rich to the point of spitting oil out fairly heavily and sounding like a four stroke.. ran it at full throttle for about two minutes followed by about 30 seconds of idle and back to full, through the tanks. By the time the third tank was done, it was running sweet and pulled those planes along perfectly.

Each one starts up on the first or second flip when cold and starts up with a slap on the prop in the reverse direction on the first try. Sweet engine.

CGr.