Four main forces act on an aircraft in flight are: Thrust (if the aircraft is powered), Drag, Lift, and Weight. We are concerned only with Lift and Drag in our analysis here.

The Lift Coefficient and the Drag Coefficient represent the changes in lift and drag as the angle of attack changes. CL and CD are not expressed by any physical unit, they are rather absolute numbers obtained from either wind tunnel tests or derived mathematically.
Initially both CL and CD increase as the angle of attack increases. At a certain point, the lift begins to drop while the drag increases sharply. This point is defined as the Critical Angle of Attack. If the angle of attack increases passed the Critical Angle of Attack, at one point all lift will be lost while the drag continues to increase.

In this contribution we evaluate the values of Lift and Drag Coefficients for specific conditions and examine the nature of their relationships with different factors and characteristic variables.