So this is the main reason it is advantageous to put the prop
farther out away from the cowling  or make it as slim as possible?
Perhaps  alleviate much of the high pressure area between the prop
and cowling.


DougFir

You would think so but the pusher prop so far has not been
proven to be that much more efficient.

There are at least two ways to model a propeller.
One is use the momentum theory as alluded to above and one
is the pressure difference theory on the prop blade for
lack of a better term.

Klaus and I were having a discussion on what keeps airplanes
up the sky. I said it was the pressure difference on the
wing and Klaus said "Shame on you Paul. You are wrong!
Don't you know anything?":) He said it is the mass
of air accelerated downward.

Both are true.


Paul Lamar ...No rotor no motor.
------------------------------------------

Because the pressure differential assists with the mass acceleration of
the air downward.  Ultimately it is Newton's third law of motion that
keeps the plane up high.
In many texts it is referred to as momentum theory.

Bob Y

True. Here is the rational I am using for the prop program.

From "Theoretical Aerodynamics" by L.M. Milne Thomson

Paul Lamar ...No rotor no motor.

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