The formal definition of lift is the mechanical force generated by a solid object moving through fluid. It is the force that directly is opposite to the weight that holds a flying object down. Lift can be created by any part of the object, but the most lift is created by the wings. It occurs when a flow of gas is turned by an object in one direction. Then the lift occurs in the other direction. To calculate lift, there are a few numbers that you will need to use.
Measure your wing area. Your wing area is the length of your wing times the width of your wing. If you are measuring a biplane, with two wings, measure both. This number will be called A, for area.
Use the density of air. The density of air is approximately 0.00237 slug/ft. cubed. This is the amount of volume that the air has.
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Calculate your velocity. The velocity of the air is the speed that the plane is going, relative to all that is happening around it. For instance, if you are flying at 35 mph, but there is a wind blowing at you at 25 mph, then your velocity is 10 mph.
Calculate your coefficient, or CL. CL is also called your lift coefficient. CL is two times "pi" times the angle of attack, in radians. To find the angle of attack you would draw a line that follows the wing line, and then draw a line that is parallel to the direction of the flight. The angle that is created by these lines is called the angle of attack. Measure it in radians. Use 3.14 for pi.
Make your final calculation. The final calculation for lift is to multiply density and velocity squared, divided by tow, then multiply by coefficient and wing area. This number will give you the total lift of your flying object.