PURPOSE

To demonstrate how the flow of air against an airfoil (wing) creates lift, causing the aircraft to rise.

AIRFOIL CONSTRUCTION

1. Cut out the airfoil pattern and place it on the edge of a piece of Styrofoam.  The Styrofoam should be thick enough to trace the pattern onto and about 4" to 6" long.  If your school has a science lab, ask the teacher in charge there to place the Styrofoam on its end and cut it out for you on the band saw.  Otherwise, use a serrated bread knife.  After cutting out the shape, sand the surface until it is smooth.  (Making airfoils that will fly is an excellent homework assignment for students -- see Enrichment Activities.)
2. Take two 12" lengths of wire coat hanger and bend the end of each into a circle which fits around a dowel stick (at least 1/4" diameter). The dowel should be approximately 18" long.
3. Dip the ends of the wires into glue and insert them into the edge o the wing to a depth of 1".
4. As shown in the illustration, insert the dowel into the two circles you formed in the wires.  (Tape a small wooden block onto the dowel so that the rear wire loop cannot be blown back along the dowel when the fan is turned on.)

PROCEDURE

1. Follow the separate instructions for making the airfoil.
2. Hold the dowel in your hand so that it is horizontal and the airfoil is hanging down in front of the fan and facing it head on.  Have someone turn the fan on.  The airfoil will create lift from the flow of the oncoming air because of the pressure differential caused by the airfoil's shape.  Once you have the airfoil lifted by the wind from the fan (that is, when the wing is flying) and you tilt the dowel upward enough, the angle of attack will become too steep and the wing will start dropping down because of the turbulence formed on its top surface.

NOTE: Experiment with this procedure before demonstrating it to the class.   Just as a pilot learns to fly a plane, you will have to get the "feel" of flying the airfoil.