Capt Pit Bull:
The issue I’m disputing is the assertion by italia458 (note, he raised it, not me) that a plane at standstill can knock out 200 BHP and generate static thrust, yet there is zero THP.
“italia is correct.”
That’s a very definite conclusion to draw from the rather subjective argument you offer.
“Oggers, you don't understand efficiency.”
‘Power out over power in’ is pretty uncontroversial.
Unless you are at least prepared to consider that something you think you understand could be wrong I, like italia, see no point in spending any time over it.
THP = BHP x PE. If the thrust is not zero, PE cannot be zero, therefore THP is not zero. There is another equation out there based on airspeed for an arcraft in flight but it does not invalidate this one or vice versa. The trouble is Pit Bull, that italia458 is insisting it does, and you assert that he is correct. I would call that dogma and therefore I have to chuckle at the irony of your post.
“An engine in a test bed does NOTHING except churn up air thereby producing heat."
It develops thrust.
"If the object an engine is attached to does not increase in the total of GPE +KE as a result of the efforts of the engine then no *useful* work is being done..”
Well, hopefullly the engine won't "increase in the total of GPE + KE" during the test because that wouldn't be terribly "useful work". It is on the test-bed for a reason. It is developing thrust and fulfilling a purpose other than moving an aircraft. You are entitled to your opinion - in a certain context I would agree with it - but it does not lead me to the conclusion that the propeller efficiency is zero, or that static thrust = zero THP.
Applying this to the helo scenario, if I want to maintain a steady hover, the work done on the air which provides the thrust to keep me there is 100% useful work. In no sense is it wasted.