We can calculate the efficiency of any process that we choose to look at.
How efficiently do I digest my food? (not very efficiently, judging by how much I eat and how little exercise I do)
How efficiently do my children use my money? (not at all efficiently)
How efficiently does the government use my taxes (worse than my kids)
If you want to look at how efficiently a propeller produces thrust then that's OK, but it is not propeller efficiency.
Propeller efficiency = THP / BHP
THP and BHP both have very specific definitions, which means that propeller efficiency also has a very specific definition.
THP = Thrust x Aircraft Velocity
So Propeller efficiency = Thrust x Aircraft velocity / BHP
So you will not prove that a propeller is producing THP when the aircraft is not moving.
I (and most of the people reading this thread) am happy to accept the fact that when an aircraft is being held on the brakes, the propeller does a lot of work in propelling the propwash rearwards. But it is doing no work whatsoever in propelling the aeroplane forwards. So it is producing no THP.
As I said to oggers in a pervious post:
If we look again at the basics:
Work is done when a force moves its point of application in the direction of the force.
Work = force x distance.
Power is the rate of doing work
Power = Force x distance / time
Power = force x velocity
From the above we can see that THP = Thrust x aircraft velocity.
Now look at your hovering model aeroplane and give us a logical explanation of why you believe that some THP is being produced.