Soaring Science: The Aerodynamics of Flying a Frisbee [Scientific American]
Introduction
Are you good at tossing a Frisbee? Have you ever wondered how a Frisbee is able to fly through the air so well? If you can throw a perfect, arcing curve right on target, you've already trained your arm to aid in the aerodynamics of Frisbee flight! In this activity, you'll investigate how the angle at which you throw the Frisbee affects its flight direction and distance. Next time you're out tossing a Frisbee, this little lesson in aerodynamics may help make your throws even more accurate!
Background
Two key forces that act on a Frisbee during flight are lift and drag. Lift is the force that allows the Frisbee to stay airborne, and in flight it opposes the force of gravity on the disk's mass. The Frisbee itself creates this lift force as it flies through the air. Because of the Frisbee's curved shape, the airflow above it must travel at a higher velocity than that underneath, thereby creating low pressure above and high pressure below the disk. This pressure difference provides the lift. Drag is a resistant force on the Frisbee, perpendicular to the lift, and it acts against the disk's movement through the air. The angle at which the Frisbee is thrown, which we'll call the "launch angle" (aka the angle of attack), affects both lift and drag.
As a side note, you've probably noticed that a Frisbee doesn't travel far if it's thrown without spin. Spinning the Frisbee helps it fly by supplying angular momentum, which helps keep the Frisbee stable; the faster it spins, the more stable it should be.
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