Fatigue is a matter of time and / or cycles.
So, let’s assume we have two identical model piston aero engines that were manufactured at the same time, are fitted to the same aircraft type and have exactly the same number of cycles and exactly the same time in service with the same operator.
However, let’s also assume that one engine is always run in the cruise at a mixture setting that produces internal cylinder pressures of around 600 PSI, and the other is always run in the cruise at a mixture setting that produces internal cylinder pressures of around 1100 PSI.
Which of those two engines is more likely to have a cylinder failure first? (Fingers crossed and breath bated for a potential breakthrough…. )