Courtesy
of NASAForces
Courtesy
of NASA
Lift is the force that keeps planes in the air. The equation that we use to calculate lift is:
L = Cl * A * .5 * r * V^2
Where Cl is a lift coefficient that is usually determined experimentally, depending upon the shape of the wing or surface that is being tested. The letter r is used to designate density and V is the velocity squared times the A, the area of the wing.
The second major force in aerodynamics is Drag. This force depends on some of the same factors as lift.
D = Cd * A * .5 * r * V^2
Once again the first term Cd is a coefficient that is determined on many other factors. Here the area, A is a 'reference' area, which is the total surface area that is against the direction of motion. The letter r, is again the area and V is the velocity.