RE: OS 55AX
One by one
fuel used: 20% castor little or no nitro
running time: nearly an year, twice a week about 4 flights each time. This engine had the head replaced in February (I damaged the original head by puting in the glow wrong)
prop: initially 12x6. I replaced it with 11x6 in April after which I did more areobatics
After I replaced the head, most people said that it didnt seem to have compression. But it ran fine.
In July (in the off season), I washed the engine with thinner (paint solvent similar to turpentine. Suggested by my instructor). Problems started after that- would cut off in flight usually when inverted. However, in the last two weeks before it broke, it seems to be running ok. It got damaged in air at 40% throttle as I was circuiting to land after doing all my aerobatics in my first flight of the weekend.