The problem I think huntley and I had was that the mounting bosses broke off the engine case. A new coil was not the solution, at least that was so in my case (sorry for the pun). A new case was going to cost me about as much as the conversion, plus I would have had to go in and do a complete engine teardown and reassembly. The CH system was a no brainer.

My 41 has spent time in a 1/3 scale Cunningham designed Druine Turbulent (low fat winged open single place home-build type from the '50s) and a Nosen 1/4 scale L-4 Cub. Sorry, I can't spell 3D, much less fly it. Could not comment, except that the power to weight ratio of the US41 is not close to that available on the current market. A good solid engine, but no powerhouse.

Have fun!

Bedford