How does drag affect an aircraft in flight?

Drag is the force which delays or slows the forward movement of an airplane through the air. It is the friction of the air as it meets and passes over and about an airplane and its components. The more surface area exposed to rushing air, the greater the drag. An airplane's streamlined shape helps it pass through the air more easily.

Drag is created by the force of air particles striking and flowing around the airplane, and it is overcome through thrust. If you've ever tried running or riding a bike into a strong headwind, then you have directly experienced how hard drag can be to overcome at times (in the case of riding a bicycle, you create thrust by pedaling).

For more information on the force of drag and some nice diagrams click here

An experiment with paper shapes to investigate Drag

Materials:

Procedure:

1. Cut two (or more) index cards into strips about 2 cm wide.
2. Bend one strip into a circle and tape the two ends together.
3. Form the remaining strips into other shapes: square, teardrop, etc.
4. Place the shapes in a row on a table.
5. Place the blow dryer so its air stream will flow along the surface of the table. Turn it on low and try blowing the shapes off the table.

Think about the following:

• The shapes that shift the most easily have the most drag, or air resistance. Those that move least are the most streamlined. Which of your shapes had the least drag? Can you design an even more streamlined shape?

Reference:
Herbert, D. and Ruchlis, H. (1968, revised 1983). Mr. Wizard's 400 Experiments in Science .
North Bergen, N.J.: Book Lab.