2013年9月4日星期三

Disc golf theories

Disc Golf Information: Theories About Disc Golf Spin and Flight Properties

One of the theories is comparing the spin of a disc to a figure skater. They start with their arms out ( more Gyroscopic) to get them spinning at first and pull there arms in( Centrifugal) to keep them spinning longer. With this comparison, gyroscopic discs are easier to make spin faster but wont stay spinning as long.

If you make the same comparison to the recent trend in yo-yo’s used for competition, this may appear contradictory. Lead is added to the outer most rim in high end yo-yo’s and they are now spinning up to 4 time longer than those without the added weight. There are of course several different factors involved, with the main difference being a yo- yo has a stationary axis of rotation without the angle of nose or effect of lift, drag, etc.

Without regards to the shape of the discs wing and dome on the top of a disc,, more gyroscopic discs go more to the right and more to the left than centrifugal discs of relatively the same wing shape. These theories are in need of more scientific testing in my opinion. There has been so much research done on circular displacement by big aerospace companies like Boeing and Nasa over the last 60 years, but information is hard to find as very little is ever published.

Discs that have more weight at the rim by % are more likely to canter and fall off against the spin as they loose velocity and rotation. The resistance of air under the nose also effects how much a disc will fade. This is the combination of shape between the underside of the wing ( flat, concave, convex) as well as height (from leading edge to bottom of wing or bead and the rim depth. The more gyroscopic and resistance under the wing the more overstable a disc is and more resistance to turn it will also have. This can be offset with the dome on the top of the disc, but discs that are more gyroscopic than centrifugal always seem to fade more at the end even if the deflection angels over and under are equal.

If we made a flatter wing for the Sabre/ Hybrid / Blaze / Demon they would all become way less overstable as well as easier to turn and maybe even flip.
adding this extra plastic will also increase the gyroscopic spin but only the Hybrid with the thinner flight plate would it actually effect the ratio between rim and flight plate. The Sabre/ Blaze/ Demon all have .085 plus thick flight plates. Typically a Sabres ratio of weight from rim to flight plates is about 85 grams rim – 90g flight plate( closer to that of a mid-range disc) in a 175 gram disc while a Hybrid is more like 95 rim-85 flight plate.

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