Here I am clipping along at just a couple of feet above 1000' where the outside air pressure is 2040 psf. Some instrumentation tells me that the average pressure on the bottom of my 63-series airfoil is 2020 psf, while the average pressure on the top of this wing is 2000 psf.
The wing, except for some ribs and spars, is basically hollow, and is filled with air at the ambient pressure of 2040 psf. Looking at a diagram of the pressure acting on the upper and lower wing surfaces, I see that there is 2020 psf pushing up on the bottom surface, and 2000 psf pushing down on the upper surface.
But the air in the wing is pushing down on the bottom surface with a pressure diffential of 20 psf, and at the same time is pushing up on the top surface with a pressure differnential of 40 psf.
So, could it be said that the wing's lift is really a result of the air in the wing pushing up on the top surface 20 psf harder than it is on the bottom? What say you? And please don't invoke the idea that there is a force called suction! Air doesn't suck, it only blows!
And yes, airfoils with curved lower surfaces have lower pressure than ambient in flightl
The wing, except for some ribs and spars, is basically hollow, and is filled with air at the ambient pressure of 2040 psf. Looking at a diagram of the pressure acting on the upper and lower wing surfaces, I see that there is 2020 psf pushing up on the bottom surface, and 2000 psf pushing down on the upper surface.
But the air in the wing is pushing down on the bottom surface with a pressure diffential of 20 psf, and at the same time is pushing up on the top surface with a pressure differnential of 40 psf.
So, could it be said that the wing's lift is really a result of the air in the wing pushing up on the top surface 20 psf harder than it is on the bottom? What say you? And please don't invoke the idea that there is a force called suction! Air doesn't suck, it only blows!
And yes, airfoils with curved lower surfaces have lower pressure than ambient in flightl