"The Flight of the Frisbee"

SUMMARY OF PROJECT:

When the Frisbee is thrown there is a certain grace about its flight. This is different from most sports apparatus, the Frisbee stays at level flight unlike a football of tennis ball (projectiles). It is also very natural to throw a disc especially the backhand. A simple throw with a natural wrist flick allows steady flight.

Why does it fly like this?
That’s the question which we have tried to answer. And that is a definite reason why we took part in the Young Scientist 2007. Project work and research is actually fun when it is based on something that interests the student. We chose Frisbees because we had a desire to learn the science behind it. This made work easier to complete instead of it being a chore.

Our main goal is to be able to understand and accurately predict the flight path of the Frisbee from the back of the swing to where it lands. We want to investigate the throw and get a definite understanding of what exactly is happening. This means we need to understand everything from the biomechanics of the throw to the parachute style landing.

We studied the aerodynamics, mathematics and physics of the flight of the Frisbee.

Our methods of test, monitoring and observation were as straight forward as possible. We monitored the Irish Captains of Ultimate Frisbee, Mark Earley and Alan Doyle, throwing a Frisbee. From this, we developed ideas on precisely what we wanted to do and to investigate. We took our measurements on speeds and distances from them. This is important as they are simply the best in Ireland at throwing a Frisbee. We are far too inexperienced to be able to compare to their level and skill.

They also gave us some idea into questions which we wanted to answer in the project.
For example: they gave us a brief idea on how wind affected the Frisbee. We then decided to test their ideas and put a scientific explanation to it. Then we could jump off on that and consider more complicated problems.

When working on the mathematics of the flight of the Frisbee, the forces were divided up. This includes: Lift, drag, thrust, weight. We worked the mathematics of each separately and worked out the possible new forces of each.
For example: when the Frisbee is travelling and has a vertical vector, there must be a drag on this vertical movement.
By applying formulas, we were able to work out all the variations of the flight of a Frisbee. Drag, lift, and trust were all worked out in formulas. Then based on the measurements taken from Mark Earley and Alan Doyle (Captains) we were able to put figures for each force.

- We then looked into trick throws such as the air bounce. Using vectors, trigonometry and the knowledge we already had on forces, we could put together a mathematical model of what happens.

- Curl throws are yet another extraordinary feature of a disc in flight. Again using vectors and basic lift and drag theory, we were able to make an equation for its flight.

- Wind has a big affect on the flight of the Frisbee. For novice players, wind can ruin the game of Ultimate or Disc Golf. We have studied the effects of wind and have made a list of tips (based on aerodynamics) to counter the wind.

The particular type of Frisbee we are testing on is a 0.175gram. It has a maximum diameter of 28cm, a 2cm deep rim and a 26cm inner diameter. This is completely standard to a particular Frisbee sport called Ultimate. That was important so we could keep data and measurements constant. The reason we choose this is because this game involves the most throwing actions and it is the most popular.

We also worked out the minimum speed needed for level flight. This is varied depending on the angle of attack. The higher the angle, the more lift and therefore the less velocity is needed.
When we tested all this information, it worked out. This really shows how science and physics matters in everyday life.

Ian O’Connell
Robert Conway
Stephen Rynne

(Fourth Year 2006/2007)