02 Apr 2012

# Giant Frisbees

It would be interesting to investigate the aerodynamics of these giant flying discs:
https://www.instructables.com/id/Giant-Flying-Discs/

CE Designer

Branch Unspecified
02 Apr 2012
Very interesting indeed!
The challenge with big frisbees like this is getting the spin. It is the spin that allows it to stay suspended in the air for so long. The frisbee is aerodynamically designed with smooth curved edges that allow air to flow above the frisbee easily.
In aerodynamics, fluid moving at high velocity on top of a surface creates a low pressure at the top and therefore a lifting action at the bottom of the surface. So the frisbee, like the wings of an aeroplane, is designed so that air can flow easily at the top of the frisbee. The spin also allows easy air flow over the frisbee and overcome air resistence.
02 Apr 2012
CE Designer
Very interesting indeed!
The challenge with big frisbees like this is getting the spin. It is the spin that allows it to stay suspended in the air for so long. The frisbee is aerodynamically designed with smooth curved edges that allow air to flow above the frisbee easily.
I agree about the lift. There is more to it. There is a gyroscopic stability that keeps the spin axis vertical in horizontal flight. If the spin axis is kept off vertical this adds a precession force, which causes interesting flight paths. It is for this that one needs a good spin. We can study (theoretically) effects of spin speeds and degree of tilt and see what comes up.

CE Designer

Branch Unspecified
02 Apr 2012
bioramani
I agree about the lift. There is more to it. There is a gyroscopic stability that keeps the spin axis vertical in horizontal flight. If the spin axis is kept off vertical this adds a precession force, which causes interesting flight paths. It is for this that one needs a good spin. We can study (theoretically) effects of spin speeds and degree of tilt and see what comes up.