RE: Great Planes PT- 17 Stearman ARF
It all depends on your flying style and what you want the plane to do. GP says a 91 four stroke flys it and I believe it will for scale flight. I think the Saito 100 would be nice replacing one of the seven cylinders like I did with the 120 but its 8 ounces lighter, would need to make the tail lighter. The 120 flies it very well and I am real happy with it but its not a 3d machine with this motor. Keep it light and you could use a smaller motor. Pull pull on the rudder would remove about 18 grams from the rear. Moving all the servos forward would help also. I think its possible to get this under 13 pounds with some work. Note my battery pack is on the top of the motor mount and I didn't add lead.
Carl