Some great input...thanks guys! I like the steel sleeve, no chrome to peel. With a ringed piston this should mean that unless you're one of the 8 or 9 people on earth who fly model airplanes for a living the thing should last forever, or at least until it's obsolete.

For me, the weight's not a real issue as I'm not flyinging high-performance planes. The weight issue seems to stem from the fact that no matter how small the engine is, the ignition battery pack and ignition are going to weigh the same. This means that gas engines can only get so small, at least until some breakthrough occurs in batteries and/or the ignition packaging.

As I'm eyeballing the inside of my 4*40, I'm also seeing that packaging is going to be a bit tricky with this engine, stuffing 2 battery packs and an ignition into a 40-size fuselage.