I replaced an OS91Fx I had in a Swallow with the YS1.10Fz Heaps more power, mainly in torque in the uplines, plane is a delight (sorry, was!. Shot down on the weekend) with this motor. I had a steep learning curve with the 1.10 but when it runs, it is just an awesome motor. Spins a 15x8 at 8600.

Steve