Originally Posted by Mike-Bracknell
I come from the world of cars
Er, Bracknell, cars, sounds rather interesting. Looking forward to 13 March I guess? Or 27th?
I think the point about ignition improvements relates to vibration. By improving the ignition and making the engine run smoother the onset of propellor vibration is at a higher rpm. Prop vibration is torsional in nature and is caused by aero engines having no flywheel so producing torque variation as the cylinders take it in turns to go bang. In this airplane the prop vibration band is 2250rpm to 2550rpm. Vibration is affected by prop diameter (mustn't be reduced below 72.5 inches during repairs) and compression ratio (nominally 8.5:1).
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