Is the aerodynamic lift of a jet wing zero at zero angle of attack? If so how does it fly?

Question

As a corollary to this, is the value of the lift force up to the point of stall a linear function of the angle of attack or based on the trigonometric sine of the angle of attack? I post these questions in a sincere wish that confusion within these technical studies be eliminated including my own.

It is continually surprising how little is understood about flight even in academic and professional circles. A controversy over these questions rages on Wikipedia, the on-line encyclopedia, on the subject of the Lift (force) to the point that an "Under Dispute" tag has been placed on it - see http://en.wikipedia.org/wiki/Lift_force .

Answer 1

True angle of attact is measured from the "zero lift line" not the aircraft's longitudinal axis as reference. Therefore, the way you have asked your question, the aircraft's lift force at zero AOA measured from the longitudinal axis is *not* actually zero. It is a positive number. Without lift nothing with mass can fly. It is not allowed by physics.

Answer 2

An Aerofoil Section Will Also Generate Lift At Zero Angle Of Attack

Read Up On Bernoulis Prinviple

Answer 3

Aerospace engineers have successfully proved that a bird can not fly... But yet it does ???? The wing design (shape) itself might create enough downward drag, or resistance under the wing as opposed to no drag over the wing to create enough lift (vacuum) to keep the plane (or bird) afloat with wings fixed at a zero angle. This vacuum affect is created just above and behind the trailing edge of the wing. It is also very difficult to calculate. You have to consider other factors outside of lift force, angle of attack and linear functions. you now need to consider air density, total weight, combined drag, temperature.

Answer 4

It depends. If the wing has camber (it centerline is curved) then at a zero angle of attack it will have lift. If it is not cambered than it most likely won't. This is all assuming you are not maneuvering and have not twist. As for the lift curve slope, it is easiest to approximate the lift coefficient (lift/(dynamic pressure*Area)) as a linear function at low angles of attack (a few degrees), after which it goes non-linear as it approaches stall.

Answer 5

It depends on the cross section of the wing. A classic asymmetric airfoil will generate lift at zero angle of attack, while a symmetric wing will not. Every wing has what is called a zero lift angle of attack, which is the angle of attack at which it generates no lift. It is different for every wing cross section.

Answer 6

Tom H brings up a good point about the stunt plane.But a stunt plane is more like a prop driven missile. If the engine where to die it would fall like a rock. The engine is what puts it in the air and the flight surfaces are there basicly to direct it around like the control fins on a missile or rocket

Answer 7

zamir is correct. Don't get hung up on Bernoulli's principle. Yes, it is correct. But can you explain how a stunt plane can fly?

Stunt planes have wing foil shapes that are symmetric top-to-bottom, just like an efficient boat rudder foil. They can fly because a positive angle of attack generates positive lift.

Answer 8

Hi, the angle of attack does not matter. The bottom of a wing is flat, and the top is rounded. Air flows faster on top of the wing and that creates the lift.

Answer 9

Here is the information you requested in your question;
http://www.cfdrc.com/bizareas/aerospace/aeromechanics/aircraft_aerodynamics.html
for further research go here >>
http://books.google.ca/books?q=Aerodynamics+of+jets&ots=HpDpvXYOPH&sa=X&oi=print&ct=title