Instruction

In this applet, the variation of forces acting on an NACA 2410 wing section is demonstrated.

Use two sliders on the right to change the airspeed and the angle of attack.

Question: Why does a pilot have to increase the angle of attack when he slows the airplane?
Try reducing the airspeed while keeping the same amount of lift (i.e., weight.)

Also note the decrease in lift beyond a certain angle of attack.

Deploy and retract the split flap and see its effect. (A flight instructor will tell you never to retract the flap on a final approach to landing. Do you see why?)

More detailed information:
For this numerical illustration, forces per unit span are computed assuming the 1.6m chord length. Within the range of relatively high Reynolds number chosen, the Cl and Cd curves are assumed to be independent on the Reynolds number.
Change in the center of pressure is not shown for clarity. Refer to a separate pitching moment simulation.

(The data taken from Abbott and von Doenhoff, "Theory of Wing Sections, pp. 476-477. )

Glossary