Hello everyone,

I need some advice with with a recently completed Balsa USA Scrapper.
The first flight with the model was with a Fox 40 Delux, 10x6 Master Airscrew prop and Wildcat 10% nitro 16% oil fuel. During the first flight the plane easily exceeded 100 mph however the glow plug blew which resulted in a deadstick landing. The engine was hot.
I allowed the engine to cool and replaced the plug with a Fox standard long with idle bar. I richened the top end to about a 200 rpm drop. The plane flew the next two flights at half throttle, however the engine still ran warmer than usual. The fourth flight I replaced the Master Airscrew prop with a 10x6 APC and leaned the top end back towhere I normally run (50 rpm drop). Again the Scrapper exceeded 100 mph and the glow plug blew.
The engine has been on numerous airframes and have never had a problem in the past. The props were both balanced and the fuel tank is set in foam. Any ideas?

Chap