Italia: I’ve been reviewing the thread and would like to respond to some of your previous comments in light of recent developments:
“We were never talking about induced power. Don't blame me for your inadequacies in understanding material. I kept it pretty simple I thought - obviously not. I never said that the propeller wasn't doing any work.”
I’d like to give you the benefit of the doubt but I’m afraid the suggestion that you were sitting on this knowledge about induced power (just when the aircraft was still, obviously, the rest of the time you call it THP) doesn’t quite dovetail with a lot of what you have written:
“It might be good to specify that the "power (lift)" you mention is BHP(SHP) as we've been talking about THP…
The engine is using a ton of energy (fuel) to create that force (thrust)... but since the thrust isn't moving the aircraft, the thrust isn't doing any work. Therefore, there is zero Thrust Horsepower…
When you're talking about Total Rotor Thrust, that's just thrust..
That force (Total Rotor Thrust) comes from the power of the engine (BHP or SHP)…
I believe that when the helicopter is in a fixed position over the ground the THP will be zero. The engine will definitely be creating lots of BHP(SHP) and burning lots of fuel to produce the thrust that is keeping the helicopter in the hover - but I believe THP will be zero. Work will be done to lift the helicopter off the ground into the hover position which will obviously make a certain amount of THP.”
etc etc. Would've been so much easier just to mention induced power.
“Can you provide evidence that my point is different than what is said in the references I provided?”
Yes. That navy reference you keep using states clearly at the top that it is predicated on the assumption of “equilibrium flight”. That doesn’t include sitting on the ground. For that you need the alternative method of calculating power output from the book and the essay I linked to.
“But the 'Navy stuff' clearly showed that you were in fact creating zero THP when the aircraft was stationary!”
Forgive me for labouring the point as you do seem to rely on that equation, but it assumes equilibrium flight as stated clearly at the top of your reference document. An aircraft on the ground is not in equilibrium flight.
“THP has its own equation - if you want to see if there is THP in a situation, you need to use it. As stated numerous times, if the flight velocity is zero, there is zero THP - that is what the equation says, not me.”
And so.
OTOH, a helicopter in the hover [where you insist there is no THP] is in equilibrium flight. The aircraft itself is not moving but there is a velocity which is the induced airflow. You have acknowledged that there is thrust. Therefore you can apply the formula – weight x [velocity of induced air flow]. The result is THP. It has to be because it’s the power associated with the thrust. Although you insist there is no THP for a helo in the hover.
The same could be said for an aircraft in equilibrium flight into a strong headwind such that groundspeed was zero. You have been very clear:
“I have been very clear in describing that if the 'vehicle' is not moving, then the THP is zero... THP is related to the distance that the aircraft moves with reference to the earth.”
I'd suggest the THP is exactly the same into wind as it would be downwind and the earth has nowt to do with it.
And I really like what you did here:
“There is no need to complicate this with special or general relativity…”
Followed a few hours later by:
“General relativity deals with the theory of gravitation. I will try to explain a little bit about what's going on below.”