Engine failure - Zyclone R80

Whilst out flying recently my engine stopped over Ashdown Forest. I landed safely without drama.

My Zyclone motor had done 44 hours  - a PAP80 clone but better made - and
the following was found on inspection. See picture sequence with notes on attached PDF file below.

The engine had run perfectly until this point. Regular inspections of the spark
plug had always shown a mid to dark brown colour such that weak fuel/air
ratio was an unlikely primary cause of the failure. However, head gasket
creep would appear to have taken place projecting gasket material into the
combustion chamber. This appears to have caused sustained engine detonation
adjacent to the inlet side of the combustion chamber. Notice erosion of the
gasket material.

I am replacing the aluminium cylinder head gasket with a custom made
annealed copper item with a bore diameter 0.5mm larger than the original
gasket. I hope that this does the trick.

Happy flying

Frank Ogden

Engine Pictures & Notes (PDF 1.56Mb)

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