Are we discussing rotor-propeller interaction, fuselage-propeller interaction, or wing-propeller interaction here? The objective of the discussion, hence the reason for my explanations, seems to be constantly moving.
From the beginning, the subject has been directed at the aerodynamic related location of the propulsion (propeller) in respect to the location of the lift (by; gyro-rotor, heli-rotor or airplane wing, which all do the same thing). Don't move your explanations.
The report in post #491 make mention of a 3% advantage for the tractor. Two previous aerodynamic arguments for the tractor are mentioned by other people in the middle of
this page.
There is no argument with your basic algorithms related to thrust. However, it appears that the interaction of these two streamtubes does more than just re-vector the thrust.
Coincidentally, that report also discusses contra-rotating propellers. The 0-7% advantage due to the fuselage is of related interest, since the smaller ABC helicopters will have their propulsors located on the centerline of the craft. It is also of related interest since Kamov appears to be moving in that direction.
Mart, you have previously criticized me for hopping from concept to concept. I'm not building a helicopter, therefore there shouldn't be a bias. Personally, I would prefer the
pusher for a number of reasons unrelated to aerodynamics.
Since X2 is gently accumulating flight time i would say they got it right...
The principle objective of the X2 is the, yet unachieved, high-speed flight. IMHO, salesmen should be optimists. Engineers must be skeptics.
Dave
Edited, in red, to correct error, 'tractor' was typed by mistake.