Reduced Performance from Piston Engines
We worry about turbine engines degrading in performance (particularly in helicopters), and we seem to think that piston engines either work properly and completely and are always able to put out 'baseline' power.
A recent discussion with a friend of mine who flies piston engine helicopters indicates that may not always be the case.
Which leads me to my question - how can we determine if a piston engine (with a manifold pressure gauge) is putting out the power it should be putting out?
Any thoughts? What does the fixed wing world do to determine if a cylinder doesn't have the proper compression, for example?