I have a GMS .76 in mine and it flies it with authority, alot faster than scale with alot of vertical. A Saito 100 is not really needed, a saito 82 would be a better choice and still be plenty for the Sopwith. The problem with the 100 is the prop size, This plane is hard to handle on the ground as it likes to loop on the ground. The bigger prop means more torque witch in my openion, harder ground handeling.