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Game tips — The disc’s flight
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How does it work?
Anything can fly if it is given enough kinetic energy or if it is lighter than air. A cannon ball of the old classic type shouldn’t really be able to fly, or at least not fly very well. It is rather transported through the air as long as the kinetic energy is more powerful than gravity. When talking about flying, we usually mean a forward movement through the air that requires minimal energy consumption and that has good lift capability. An albatross is an example of a low energy flier while a magpie is a high energy flier. Likewise, a sailplane is a low energy flier while a fighter plane is quite the opposite; with about the same lift capability as a brick.
A disc is a low energy flier, but it does have limitations when it comes to power supply. The only time it flies is when it is thrown. It can’t help itself by flapping wings or adding gas. It can however get extra kinetic energy when thrown downhill or in strong tailwinds. A disc’s good ability to fly is due to a design that distributes much of the air it cuts through downwards, creating a counter force; a lifting force. A typical flat plate does not distribute much air downwards when thrown. Its ability to fly is almost exclusively depending on its low air resistance. It rather cuts through the air.
The high profile discs in particular can fly very slowly without losing too much altitude. All discs fly understable when exposed to enough air resistance. The term understable means that the disc’s horizontal plane flips to the right (for the right handed backhand thrower). In other words, the disc moves from a flat flight pattern to a flight where the disc is pushed by the air to lean to the right. If the disc during its flight gets tilted enough to the right, it will land on its edge with the disc’s spin going forwards. This means that it will continue its movement by rolling on the ground.
The disc’s stability
I.e. to what extent the disc is affected by air resistance. It depends on these factors:
- Weight: The heavier the disc is, the less it will be affected by air resistance.
- Weight distribution: The more weight in the rim, the less it will be affected by air resistance.
- Stage of wear: The more damaged a disc has become, the more it will be affected by air resistance.
- Design: Air distribution to above and below the disc affects the stability.
Here are some approximate figures showing the amount of aerodynamic drag (displayed in meters per second), that a disc may need to begin to turn over. However, 20 m/s could in this example represent either a throw in 20m/s (72 mph) or a throw in 15 m/s into a headwind of 5 m/s.
- 20-25 m/s for understable golf discs
- 25-30 m/s for stable golf discs
- 30-35 m/s for overstable golf discs
Another factor that affects how stable a disc will fly is how you throw it:
- Rotation of the disc: The more spin, the more stable flight.
- Purity of release: The less flutter, the more stable flight.
Flutter may either occur due to a bad release or because it hasn’t been given enough rotation. Even if the disc is released with some flutter, it could stabilize itself thanks to good spin. The opposite kind of throw could cause flutter after some airtime, if you get a clean release but don’t give it sufficient spin.
The disc’s speed depends on three things:
- The height of the disc: The slimmer profile, the faster it gets.
- The sharpness of the edge: The sharper edge, the faster it gets.
- The disc’s diameter: The smaller diameter, the faster it gets.
The disc’s ability to hover or glide depends on four things:
- Its weight: The lighter it is the better it glides.
- Its diameter: The larger diameter, the better glide.
- Its spin:The more spin, the better it glides (especially at low speeds).
- Its design: A complicated issue that is still relatively unexplored.
Another thing that can affect the disc’s flight is the Magnus Effect. This particularly applies to large, high discs that can turn sideways (without the disc turning over) if they face enough air resistance.
You will often hear players say that a disc that starts to fade off (moving into a hyzer angle), does this because the spin ends. However, if the spin would end the disc would start to flutter. In fact, the reason it fades is because it loses speed. Not spin. A strong fade could be caused by a high throw or a positive angle.
There are six basic factors in your throw that will affect the flight:
- Speed: The velocity of the disc. It could be anything between just over 0 m/s to up to about 40 m/s (140 kph) among the best in the world.
- Spin: The disc’s rotation seen from a horizontal plane. The disc can spin clockwise (i.e. the same rotation as a right handed backhand throw) or counterclockwise.
- Angle: How the disc is tilted sideways during release. It could be thrown with a hyzer angle (disc tilted down), anhyzer angle (disc tilted up) or flat.
- Nose angle: The disc could be thrown flat, nose up or nose down, as seen from the side.
- Height: The vertical direction of the throw (up or down).
- Direction: The horizontal direction of the throw (left or right). When releasing the disc in a hyzer angle, it will make a curve from right to left (for right handed backhand throwers). When releasing it in an anhyzer angle, the disc will make a left to right curve (again, for right handed backhand throwers).
By combining these factors and also considering how the wind will affect the flight and how the disc will land or roll, you could in practice make the disc go practically wherever you want.
/Jonas Löf, translated by Jonas Lindberg
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Tommy Bessner 1998 – gives the disc a lot of kinetic energy
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The disc's shape determines a lot of its flight properties:
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| Driver — low profile |
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| Midrange — medium profile |
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| Putter — high profile |
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| Classic — high profile |
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Adds
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