Astro Hogs are at the top of the list of great flying planes. INMO they would fly best with either a 70 4stroke or a 60 2-stroke but I wouldn't put anything smaller than a .50 sized engine. I recomend that even though it does not look as good to build it with a trike gear or atleast install the hardwood blocks in both locations on the wing so you can change it later. My brothers and other taildragger Hogs I've seen and flown can nose overbadly on take-offs and landings. Sig should come out with a new version of this kit thats laser cut they could sell a ton of Hog-ARF's if they would make them too.