After re-reading my post, as well as looking at Sig and BUSA'a info on the J-3, a .91 most likely will fly the plane okay. I'd really like to see one knife edge with a .91, and maybe a 2-stroke would do it. I don't even consider 2-stroke glow engines for this plane, a Cub just needs a 4-stroke or gas.....my own prejudice. Plus, a Cub doesn't look right with a smaller than scale prop, and a .91 just won't turn a 18 incher very well. There are three 1/4 scale Cubs in our club, all with either a 1.20 or G-26 (one is clipped wing). I know what kind of performance they have, which is plenty, but I think I'd want that much, because you can cruise at such low settings, but have plenty on reserve.

Edwin-- take a long look at your L-4 plans when you get them, see what you think about the top of the center section, and modifying it for a full greenhouse. I'll be very interested in your build pics. My BUSA Cub project is down my list a bit, got several WWI projects and a BirdDog ahead of it. Unless, of course, I wrap my 1/5 scale around a fence post or tree[&o].

The side outline on the BUSA L-4 windows is pretty close. I have the fortune of a recently restored full scale at a nearby grass strip, and I've measured it and compared to BUSA's plans. I don't know what it is about the L-4, or J-3 for that matter, but I'll always have one in my hangar.