Ferrydude
Even the original post in this thread does not refer to compression checks. It simply asks if wear-induced loss of compression causes a reduction in power output and if so by how many %.
Your statement that
"The TCM data does not support your position. Leakage past rings during a static compression test is usually higher than when the engine is operating."
Seems to agree entirely with my statement that
"Under these circumstances the compensating effects of the pressurised crank case will be minimal, so leakage past the rings will probably be much greater than when the engine is actually running."
We appear to be agreeing that leakage when the engine is running at normal operating rpm will be less than when it is static or at low rpm.
But we also appear to be engaged in two separate arguments. You appear to be arguing that compression checks do not give an accurate indication of power output. I agree that this is probably true.
But I am arguing that if wear-induced leaks cause cylinder pressure to be reduced in a running engine, then this will cause a reduction in power output.
The question of whether or not we can actually measure the leakage or cylinder pressures when the engine is running is irrelevant.
411A
Your statement that
"UAL was authorized to operate their R2800CB16 engines (installed on DC-6B's) to 3,300 hours until overhaul, and when one of these engines was sent to P&W for analysis, it was put on a dyno and checked for power output, the results surprised no one...yes, specific BHP was reduced, but only by three percent, and this was in the dry takeoff mode, wet takeoff, two percent. "
Simply proves that a reduction in power output had occurred, but that this reduction was not very great. It does not mean that power output was not reduced.
These results do not prove me wrong, but actually illustrate exactly what I have been arguing. Wear-induced leakage causes a reduction in power output.
Nothing in any of my posts suggests that the rate of power loss in any particular type of engine is very great. Even for a specific engine type, the wear rate and power reduction rate will vary from one engine to another.
My argument is quite simply that if wear causes a reduction in cylinder pressure, then this in turn with result in a reduction in both IHP and BHP.
If anyone would like to use the IHP equation to demonstrate that a reduction in mean cylinder pressure will not cause a reduction in IHP, then I will be delighted to be proved wrong.
Hawk37
No, I have not published any books or papers on this subject.