I was so glad to see this thread. I am still fairly new to R/C aviation, and a long ways from flying a giant-scale, mostly due to cost. The first question I had for the experienced Giant-Scale pilots at our filed was, Why they were paying so much for gas engines instead of using weedeaters motors and such, Simple: Not enough RPMS, they said., and made sense, but was sure it could be done, and glad to know it can. Also am very interested into knowing how. Flywheel? Stroked blocked?