First off, the G26 is a 1.6 cu in. engine. I'm on my second one, and this one is a B&B modified engine which is swinging an APC 18x6W at 8600 RPM static. I previously had this engine in a CG Sukhoi as a replacement for a YS 140L. The G26 swings the same prop 100 rpm more static, but the YS has less loss in flight, but not by much. My YS ran on Coolpower 30% heli fuel, which got to be quite pricey expecially with the engine's thirstiness. The biggest dowside is the weight between the G26 and the larger 4 stroke glow engines. With the Stearman, you need nose weight anyways, so why not use the engine as ballast? Gassers are so much more reliable, cleaner, and cheaper to feed that there's really no comparison in my mind. The 4 strokes are much pickier about cooling than a gasser also. I will be using a dummy radial with the bottom cylinder cut away as a cooling duct. The G26 is an easy engine to cool and I don't foresee any issues. Looks like all that will be sticking out the bottom is the sparkplug cap and the exhaust stacks. This is fine with me as this is definitely not a plane for someone looking for a scale masterpiece! Plus, I like to be able to unplug the sparkplug for safety when not flying in addition to the kill switch just in case. I've gotten rid of all of my glow engines (except ducted fan) and can honestly say that I'll never go back. It's just so nice to be able to go to the field with a plane, a transmitter, and a fuel tank and not have to take anything else--including cleaning supplies!