ORIGINAL: Pull Up Now!


Skypup, your question about the GP Stearman has two parts to it. First, is the power developed by the engine appropriate for the airframe. Secondly, is the physical size of the engine approximately correct. The 35cc Evolution radial engine is about 7.5'' diameter The dummy radial that comes with the kit is about 8'' diameter. So that's not too far off. It only is shy by 1/4'' per side. Power is another matter. The 35cc only generates about 2.2 HP, which equates to about 110watts per lb for the Stearman. This is enough power to fly, but it would be pretty scale-like. The Stearman is built pretty solid, and there may be some opportunities to lighten the airframe during the build. The Evolution engine weighs 500 grams (1.1 lbs) MORE than the Saito 120, so this is quite a lot of difference. That weight difference could bring the performance down to 103 watts/lb, which is even worse. So, in sum, I think it would work, but I'd look for ways to lighten the plane.