ORIGINAL: Mike SVOR
ORIGINAL: banktoturn
ORIGINAL: Mike SVOR
Well its not really true.
The curved top wing is designed to eliminate stall upon high angles of attack and slower than efficient speed over the wing.
There is some downward redirection of airflow going on here but at say 5 degrees of downward flow, this doesnt make the plane fly.
It's not the low pressure on top of the wing that makes a plane fly, it's the high pressure on the bottom of the wing that makes it fly.
Mike,
It is the pressure difference between the top and bottom surfaces that produces lift. It's specifically incorrect to say that it's the high pressure on the bottom of the wing that makes a plane fly. It is entirely possible, and not uncommon, for the pressure on the bottom of a wing to be lower than the ambient pressure of the air away from the wing. It is completely nonsensical in this case to say it is the high pressure on the bottom that is causing lift. Moreover, when airfoils are designed, it is common for the shape to be modified to give a specific pressure profile on the top surface. The pressure profile on the bottom surface is not generally considered.
It is more legitimate to characterize the top surface as the object of wing designers' scrutiny. In casual conversation, I would be inclined to say the top surface is the critical one, and the bottom surface is just along for the ride.
banktoturn
[respectfully]
I really don't agree with any of that, except for the designers taking careful consideration of the top wing because that would compliment the aircraft's projected speed envelope.
The top of the wing is designed to maximize airflow and NOT cause a vacuum. If it were only trying to create a vacuum, then there would be no upper wing area after the curve, creating a huge vacuum'd surface.
Take a formula 1 car's rear wing. Do you think the car's downforce is caused from the front facing (upward turned) section of high pressure or because of the back side of the wing causing low pressure and it being sucked to the ground?
Mike
It's not clear to me what you disagree with. Airplane wings can generate lift even when the pressure on both surfaces is lower than the ambient pressure. Do you disagree with this? To me, this pretty much says that it's not "high pressure on the bottom" that makes an airplane fly.
I don't know what you mean by "maximizing airflow", but the shape of the wing is definitely designed to produce lower pressure on the top surface. You have already said you disagree with this. Perhaps you could explain why.
The lower surface of a Formula 1 wing definitely generates lower pressure than the ambient air, and lower pressure than exists on the top surface. Because those wings tend to operate at high angles of attack, it's possible that the pressure on the top surface is higher than ambient, but this condition is not necessary for a wing to generate lift. To answer your question, I know that the Formula 1 wing generates downforce by creating lower pressure on the bottom surface than on the top surface. If you prefer, it creates higher pressure on the top surface than on the bottom surface. It is completely invalid to consider the pressure on either surface alone; only the pressure difference is significant.
It's not valid to assume that either the bottom surface pushes the wing up or the top surface sucks the wing up. As intuitive as this may seem, it is not a valid explanation of the way a wing generates lift.
banktoturn