RE: Sig Kadet Senior ENGINE Size
I taught a student last summer on one, and got to fly his Kadet Sr. many times. It was powered by an OS 52 four stroke I gave him, and it was perfect! Can easily do loops from a gentle dive (allmost from level flight) and can climb at full power very well. Most flying can be done at 1/4 throttle. I generally like overpowered planes, but to put anything larger on this airframe IMO is'nt necessary - it is a great sport plane/trainer/sunday flyer.
AJC