the nitty gritty is where the action is happening. Everything you said is true except flying with wings isn't about making downwash, its about making pressures that can be directed toward a surface, causing a net lift.

The downwash doesn't keep the wing up. The pressures do. When we work with slats, flaps, supercritical airfoils, swept wings, camber, angle of attack, ailerons, elevators, drag, and all the other aero type of words I could list we work to optimise the pressures, not the downwash.

Our lift equation has areas and dynamic pressures, not downwash characteristics.

We go into a wind tunnel, put a metric balance in the model, turn on the air, and measure lift on the airplane caused by, you guessed it, pressures, we don't measure downwash. I have been involved in putting pressure taps across the top and bottom of a airfoil and correlating that with the measured lift of the balance. It worked out really well. You could see pressure variation with angle of attack and Mach number and all the rest. However we made no (nada, neyt) effort to measure downwash.

I could go on and on and on, but, it would seem if Newtonian reactions causing downwash is what causes the lift on an airplane that we would spend some time to measure it somehow. I have stood at the end of the runway and felt the overpressure from the downwash as a F-15 landed, one of the fun times in my life. I felt pressure from the downwash. Pressure.

In the 39 years I have been an aero eng. covering several airplane programs we put one pressure rake aft of the wing exactly once, to check the downwash flow characteristics of flaps, the data was of trivial interest as it turned out.

Those little molecules of air are exerting a force perpendicular to the surface of the wing through a process we call pressure. We don't call that process downwash - that happens after the pressures have done their work.

With all that kind of stuff happening, why do you put some much emphasis on downwash which is only an interesting byproduct?



Speaking of tufts though, we did tuft the full size F-15 wing to evaluate the flow around the wing tip and during buffet onset. Although we know it intellectually it is amazing to actually see how much of the flight time the strings were not going aft.

Oh by the way, the transonic buffet was caused by - you guessed it - (not downwash) - but varying pressures from the shocks forming.