ORIGINAL: 321
When the engine suddenly quits, it is referred to as a flameout by most RC heli pilots over here in my part of the world. Are we talking about the same thing? If so, it can be caused by engine air leaks, lean mixture settings, a bad glowplug (which can be caused be either of the former), poor engine cooling, and bad fuel. If one of these factors makes the engine overheat, it can tighten up and/or lose proper combustion timing and quit.
I had gone through a post where a guy described his helicopter accident & said after the impact the engine ran freely without powering anything which increased the RPM leading it to burnout. It was run on Nitro. Does that mean that the piston rings & sleeve wear out due to high RPM which leads to low compression or may be damaging the sleeve or piston ?