DG Research I'd like to see..

[jeverett]

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]

As requested:
http://www.pdga.com/discussion/showthread.php?p=1286712

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]

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]

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]

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]

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:
http://webcache.googleusercontent.com/search?q=cache:J7iOu2p967UJ:https://www.pdga.com/discussion/showthread.php%3Ft%3D21815+site:pdga.com+blake+rev olutions&hl=en&gl=us&strip=1
or
http://webcache.googleusercontent.com/search?q=cache:J7iOu2p967UJ:https://www.pdga.com/discussion/showthread.php%3Ft%3D21815+site:pdga.com+blake+rev olutions&cd=2&hl=en&ct=clnk&gl=us&source=www.google.com

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]

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]

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.

[garublador]

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]

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]

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.

Hi Garublador,

For the most part I agree with you.. the precise ratio of speed to spin that produces the highest theoretical throw distance is probably only of use to the top distance throwers in the world. However in a more general sense it also seems useful in analyzing the major throwing styles, bent-elbow vs. swedish. If we can determine, for example, that flight speed has a higher correlation with throw distance than disc spin over certain ranges of speed and spin, one style or the other might be more beneficial to develop. Just as another example, why is it that many of the most-successful bent-arm throwers are also fairly large, muscular guys, while many of the most-successful swedish throwers are small and wiry (with the notable exception of Feldberg)? These are generalizations, of course, but I suspect that these occurrences have to do with the relationship between flight speed and disc spin.

[garublador]

Hi Garublador,

For the most part I agree with you.. the precise ratio of speed to spin that produces the highest theoretical throw distance is probably only of use to the top distance throwers in the world. However in a more general sense it also seems useful in analyzing the major throwing styles, bent-elbow vs. swedish. If we can determine, for example, that flight speed has a higher correlation with throw distance than disc spin over certain ranges of speed and spin, one style or the other might be more beneficial to develop. Just as another example, why is it that many of the most-successful bent-arm throwers are also fairly large, muscular guys, while many of the most-successful swedish throwers are small and wiry (with the notable exception of Feldberg)? These are generalizations, of course, but I suspect that these occurrences have to do with the relationship between flight speed and disc spin.I agree that it would be cool to find out what the correlation between style, distance, speed and spin is. IIRC, at least one of the Jarvis brothers was throwing as far as anyone at one time but the speed of the disc out of his hand was significantly slower than the other big arm throwers and no one has really had the chance to show what was really going on.

I'm just pointing out that it's irrelevant for 99% of disc golfers trying to throw farther. The last 12" of all of those styles is the same and that's where they get ~80% of their distance from. I just don't want people who want to learn to throw farther to spend all their time working on the 20% that will have minimal effect on how far they throw when they should be focusing on the 80% that can help a lot.