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View Full Version : DG Research I'd like to see..

jeverett
02-01-2011, 12:44 PM
I'm actually kind of hoping it's been done, and someone out there has a link to it.. but what I'd like to see is a study on disc golf distance mechanics that includes the use of both a radar gun (or something similar to determine disc flight speed) and tachometers attached to the discs. Basically, I'd like to see the precise positive correlation difference between the effect of flight speed vs disc spin on distance traveled. We all know that both are important, but which actually has a higher positive correlation with distance traveled? I also suspect that there will be an inflection point.. i.e. the more speed you can put on a disc, the more important spin becomes, and vice versa.. but where precisely is the balance point? Both of these questions could be very valuable to understanding how to maximize throw distance, however I've never seen the two variables simultaneously tested. For reference, a reasonable study on disc speed (only) can be found here:

http://www.aracnet.com/~stuart/disc_report.htm

Anyone happen to be able to point me to a study that actually simultaneously tested flight speed and spin? :)

grodney
02-01-2011, 01:06 PM
As requested:

That's about all I've ever seen. There is some old web article a researcher did where he attached a bunch of gizmos to a lid and took all kinds of measurements, but it certainly wasn't disc golf related. I recall him getting something like 8-12 revolutions per second, but don't quote me.

Ideally, I think you'd paint tracking lines (quadrants) on the disc, then film it from above while being thrown on a (lined) football field. From an individual frame analysis, you could measure the flight speed and the spin rate. Although the research linked above is around 33 revs per second, so you'd have a problem: I haven't looked at digital cameras lately, but mine only does 30fps max. Maybe newer cameras can do faster; otherwise you'd have to get a high-speed one. I am a little skeptical of the research in the link, as that spin rate is quite a bit faster than a couple other sources. But at least he measured it, so I can't be too skeptical.

It would be flying about 3 feet per frame at 30 frames-per-second, so that wouldn't be a problem.

jeverett
02-01-2011, 01:16 PM
Hi Grodney,

Thank you for that link. :) Unfortunately it looks like the graph itself has been taken down? :( I can't view it, and the link to it (http://img2.freeimagehosting.net/uploads/1c021b632e.jpg) doesn't appear to work anymore. It also seemed like they didn't deal with actual drive distance, which makes it difficult to draw conclusions with much utility from it. :( Do you know if Erin has done any more recent research? :) That post was from 2008, and Erin was talking about building a throwing machine. :)

grodney
02-01-2011, 01:21 PM
Ahh, here's the lid with gizmos:
http://www.lpl.arizona.edu/~rlorenz/frisbee/bigfrisbee.jpg

source:
http://www.lpl.arizona.edu/~rlorenz/frisbee.html

Hmmm, the pdf says 6.5 revs/sec, so my memory was off on that one.

In Hummel's famous paper, she quotes a typical lid throw is spinning 50 radians/sec, which is about 9 revs/sec.
http://morleyfielddgc.files.wordpress.com/2009/04/hummelthesis.pdf

This is the research that makes me question the >33revs/sec quoted by Hemmings. Possible, but that's a huge difference, especially considering that throwing a lid well REQUIRES more spin than a golf disc. Of course, Hemmings is a world class distance thrower, so who knows?

Finally, I'd be remiss if I didn't mention the (in)famous message board discussion where Blake T was claiming that a golf disc spins 8 or 10 times during the ENTIRE FLIGHT. Good one. Wish I could find a link to that.

grodney
02-01-2011, 01:22 PM
Hi Grodney,

Thank you for that link. :) Unfortunately it looks like the graph itself has been taken down? :( I can't view it, and the link to it (http://img2.freeimagehosting.net/uploads/1c021b632e.jpg) doesn't appear to work anymore. It also seemed like they didn't deal with actual drive distance, which makes it difficult to draw conclusions with much utility from it. :( Do you know if Erin has done any more recent research? :) That post was from 2008, and Erin was talking about building a throwing machine. :)

No, really my point was, that's all I've heard of, and it's not much. Certainly not the extent you're looking for.

grodney
02-01-2011, 01:38 PM
Finally, I'd be remiss if I didn't mention the (in)famous message board discussion where Blake T was claiming that a golf disc spins 8 or 10 times during the ENTIRE FLIGHT. Good one. Wish I could find a link to that.

Here it is:
or

As a bonus, Dave Dunipace posts in that thread that 6-11 revs/sec is "reasonable" and "agrees with research we have paid to have done".

BENFTS
02-01-2011, 01:50 PM
Ahh, here's the lid with gizmos:
http://www.lpl.arizona.edu/~rlorenz/frisbee/bigfrisbee.jpg

source:
http://www.lpl.arizona.edu/~rlorenz/frisbee.html

Hmmm, the pdf says 6.5 revs/sec, so my memory was off on that one.

In Hummel's famous paper, she quotes a typical lid throw is spinning 50 radians/sec, which is about 9 revs/sec.
http://morleyfielddgc.files.wordpress.com/2009/04/hummelthesis.pdf

This is the research that makes me question the >33revs/sec quoted by Hemmings. Possible, but that's a huge difference, especially considering that throwing a lid well REQUIRES more spin than a golf disc. Of course, Hemmings is a world class distance thrower, so who knows?

Finally, I'd be remiss if I didn't mention the (in)famous message board discussion where Blake T was claiming that a golf disc spins 8 or 10 times during the ENTIRE FLIGHT. Good one. Wish I could find a link to that.

I love that thread, i remember someone saying that it only spins a few times and thats it. I responded with dude my disc must spin more than that, I have it a tree and watched my disc come back to me and keep spinning on the ground. Maybe as many as 10 times before it stopped.

That was great, love his enthusiastic response but not on point with that comment.

jeverett
02-01-2011, 02:45 PM
In Hummel's famous paper, she quotes a typical lid throw is spinning 50 radians/sec, which is about 9 revs/sec.
http://morleyfielddgc.files.wordpress.com/2009/04/hummelthesis.pdf

This is the research that makes me question the >33revs/sec quoted by Hemmings. Possible, but that's a huge difference, especially considering that throwing a lid well REQUIRES more spin than a golf disc. Of course, Hemmings is a world class distance thrower, so who knows?

Hmm.. yeah, that's definitely quite a discrepancy there.. the only thing I can think of that might account for some of it is the flight speed issue. The assumption is that faster flight speed and faster spin go hand in hand (although not necessarily at the same rate, i.e. the original questions). Lids travel pretty slow by comparison to speed 13 drivers, so may well have higher spin-to-speed ratios than drivers, even if they're spinning slower than the drivers. That's all a guess, however.

02-01-2011, 03:10 PM
Both of these questions could be very valuable to understanding how to maximize throw distance, however I've never seen the two variables simultaneously tested.While interesting, I'm not really sure it's all that useful when trying to learn how to throw far. You may be able to show that some speed to spin ratio is ideal, but unless you're already a world class distance thrower trying to achieve that ratio won't help anywhere near as much as improving your mechanics and timing. If you get those right you'll be 99% of the way there. There's no sense working on the 1% until you've got that other 99% figured out.

bazillion
02-01-2011, 03:21 PM
I'm just curious to know how in hell you'd ever grip that disc with the gizmos in order to throw it! Looks to me like you'd squash a gizmo or two putting any kind of grip on it at all!

jeverett
02-01-2011, 03:25 PM
While interesting, I'm not really sure it's all that useful when trying to learn how to throw far. You may be able to show that some speed to spin ratio is ideal, but unless you're already a world class distance thrower trying to achieve that ratio won't help anywhere near as much as improving your mechanics and timing. If you get those right you'll be 99% of the way there. There's no sense working on the 1% until you've got that other 99% figured out.