One of our programming mentors whipped up this web-based trajectory calculator for the Frisbees used in this year’s Ultimate Ascent game:
http://drjohnstechtalk.com/trajFrisbee/
Hopefully this proves helpful to other teams wanting to better understand the flight dynamics of a Frisbee and making shots in the three goals based on changing initial speed, shooter angle, and shooter height.
-Chris
This is based on the work The Aerodynamics of Frisbee Flight from the Undergraduate Journal of Mathemaical Modelling.
Link, please?
The trajectory calculation runs until either the Frisbee reaches the goal height while travelling downwards…
Just wondering, why not upwards, too? From the videos I’ve seen, there will be a lot of “upwards” shooting.
Does your mentor ever participate on CD? I’m interested in his modeling approach and would like to know more about it.
Maybe this is it?
Yep, that’s it!
Hi Richard. Thanks for the link.
The calculator is based on that paper, which is in turn based on Morrison’s paper.
Morrison’s paper is wrong, I believe. His derivation for the force Fx is incorrect. He goes off the rails at Equation 12 where he says Fx is equal to Fd… Fx is equal to Fd only for the special case when the velocity V is horizontal.
For the general case when V is not horizontal, Fx is the sum of components from Fd and Fl, as follows:
Fx = Fd*(Vx/V) - Fl*(Vy/V)
Just heard back from the author. He wrote that paper as a class assignment as an undergrad. It was never published.
He agrees Eq12 is wrong. So equations 13 thru 17 are also wrong, as is the simulation.
Baumback used those equations as the basis for her simulation, so it’s wrong too.
Internet advice: caveat utilitor
Pretty neat tool.
My only gripe is that your Shooter and Goal Height inputs are in feet, while the output distance and height is in meters. The added conversions makes the tool less than useful as a “quick reference” imo.