RE: Smallest 4 stroke
The plane I fly originally had an OS25 FSR ABC in it. The FS 26 flies it just as well. I'm using standard equipment. 10x6 Zinger prop, 10% fuel.
Pilot hasn't been imported for years. Dollar to yen rate made them too expensive. We sold them at Hobby Shack and I bought many Pilot kits when I worked there. Still have several I haven't built.