I am kind of old time flyer. Started to fly with those primitive hang-glides with titanium frame and the yoke control, around 1966 and then after a few close calls and getting older I switched to small airplanes like Cessna 172 and Cherokee Warrior.
But from my decade of flying those hang-gliders I remember times when my wing fabric had collapsed because I must have been hit by a swift downdraft. I had to push it back up and hold it there a few seconds to stop stall. I needed to apply considerable upward force to push the fabric back up to airfoil shape. So I know how powerful the down-flow stream is.
If we consider the total pressure on top of the wing
$ P_{wing} = P_{atm} - \frac{1}{2}\cdot\frac{dm}{dt}\cdot v_z^2$
and vertical speed $v_z = sin(\alpha)$, so by multiplying $v_z$ by the Wing surface we get the vertical down-flow and plugging it into the above equation we get a rough estimate of lift caused by low pressure on top.
I have checked many references on how lift is created and have not found any that refer to this major component of lift which I have personally experienced. Am I missing something?
I am adding a nice sketch of me rowing a boat. Using this setting as a poor man's wind-tunnel.
If you delay lifting your row at the end of its stroke it will glide back by the force of momentum of your boat. If you keep the row steady as shown on sketch and force it to drag behind you,what happens?
It creates a small swell, with water washing the outside face of the row a bit higher, shown on the sketch on red, and on the inside face of the row it creates a vortex at front and water washes the row a bit lower than lake level, shown in green.
My question is this: after reviewing many researches by labs and NASA and many other interested parties even prestigious universities, one finds less weight given to this significant part of the dynamics of lift: low pressure on top of the wing causing air to spill down to fill in by converting part of atmospheric pressure to kinetic energy, while relieving the wing top of full force of ambient atmospheric pressure?
I did a very rough estimate assuming the 176 square feet wing of Cessna 172 made of flat balsa and came up with approximately 850 lbs at 55 kn which is the rotation speed.
I am familiar with accepted theories like Newton's change of momentum of stream of air and NACA airfoils.