The BUSA stearman kit is 1/3 scale............really big stearman! If you are going to do a stearman check out Flair's kit which should come out at around 20-25 lbs. It is a little bigger than 1/5 scale (around 4.33). I think the TechnoPower engine would be a good size match, but I don't know about power of that engine. Ziroli has plans for a 77" stearman (very close to 1/5 scale), and around 17-20 pounds which might be the perfect match.