Today I had to change my original glow plug on my OS GGT-15 engine. I had roughly 30 flights on the engine when the glow plug failed. That is not bad in my humble opinion. I have had a number of small gas engines from other manufacturers but none of them come close to the OS GGT in my humble opinion. I am quite happy with my engine, it performs very well in my Escapade 61.
Best wishes and good safe flying.
Heli-NuBee (AKA Roger the radial rabbit)