2. Airplane Control Surfaces

SUBJECT: Science
GRADE: 7,8,9
GROUP SIZE: Small or Large
TIME: 2-45 Minute periods
TYPE OF ACTIVITY: Student Investigation and Teacher Discussion
TEACHING STRATEGY: Expository Guided Discovery
CONCEPTS: Roll, Pitch, Yaw, Control Surface
SKILLS: Modeling, Manipulation of Variables

Objectives: To learn the names of the control surfaces of an airplane; to discover the effects of the manipulation of control surfaces on the flight characteristics of an airplane; to review the four forces of flight and relate the manipulation of the control surfaces to the four forces.

Materials: Three 20cm x 20cm pieces of light cardboard cut into airplane shapes (use the pattern provided); two pieces of soda straw about 7cm long; 1 pencil with an eraser or a cork; 1 straight pin; tape.

illustration of control surfaces activity

airplane control surfaces pattern

three axes of flight

Procedure:

1. Cut out three airplane shapes from the cardboard using the pattern provided.
2. Save scrap pieces and cut out three tail pieces also shown in the pattern.
3. Cut the solid lines indicated for plane 1 which will produce ailerons. Fold on the dotted lines. Tape or glue a soda straw piece on the bottom of the airplane as shown in the diagram. Attach one of the tail pieces.
4. Assemble plane 2 as shown, cutting the lines which produce elevators. Attach the second piece of straw on the bottom of the plane’s wing crossing the center of balance. Attach a tail piece.
5. Assemble plane 3 producing a tail which has a moveable rudder as shown. Attach this plane to the eraser of the pencil or to a cork as in the diagram.
6. Place a knitting needle or piece of wire through the straws of the first two planes and gently blow or hold them in front of a fan. Bend one aileron up and one down.

Have the students observe the resulting action on the plane. Reverse the aileron positions and observe again. with the second plane, raise or lower the elevator and observe the action. With the third plane, move the rudder left or right and hold in front of the air source again. Review with the students that the ailerons act on the axis of ROLL, the elevators act on the axis of PITCH and the rudder acts on the axis of YAW.

Teacher Note:

It is important that the students understand that the rudder on a plane in flight does not turn a plane like the rudder of a boat. In a plane the rudder acts on the axis of yaw. Turning is accomplished by banking the plane with the ailerons and the action of the rudder combined. The rudder does keep the plane straight or can be used to offset side forces from the wind in order to maintain a particular path over the ground. It should become apparent to the students that the control surfaces are used to put the plane into a particular attitude relative to the ground (straight and level). This attitude then allows the pilot to cause the plane to climb or descend, to turn right or left, to correct a flight path over the ground, or to do a combination of any of these things.
Extensions: You may wish to have the students do an online search for video clips of early attempts at aircraft design which failed.