Disc flight science

[Sheep]

Yeah the dome of a destroyer is not gradual but pops up, leaving a depression between dome and rim. I noticed that about the Time Lapse: its dome does not pop up but is more like a continuation of the shoulder/rim.

I'm pretty sure some of these weird things we see have a lot to do with the cooling process, like the wrath 3d scan above having a weird boob bubble.

Since we don't have the original 3d models they make the molds from, its really hard to understand what the actual disc is supposed to look like vs what happens during the cooling process.

 

[Jeffrey Homburg]

Yes. Here is a slice through a 3D scan of that Wraith, you can clearly see the funky shape of the flight plate.

View attachment 335384

What kind of 3D scanner did you use and what is the the resolution?

 

[Eric_T]

What kind of 3D scanner did you use and what is the the resolution?

This particular one was done with a Zeiss T-Scan Hawk 2, it has «up to» 0.02 mm resolution. In my experience, the scanners tend to struggle a bit with thin, sharp edges like the rim of a disc. So when I create 3D models for simulation, I typically just use the 3D scan and side profile pictures as a reference to create a CAD model.

 

[Jeffrey Homburg]

This particular one was done with a Zeiss T-Scan Hawk 2, it has «up to» 0.02 mm resolution. In my experience, the scanners tend to struggle a bit with thin, sharp edges like the rim of a disc. So when I create 3D models for simulation, I typically just use the 3D scan and side profile pictures as a reference to create a CAD model.

Thanks for that information. I've done all PDGA testing and approvals since 1989. We're now considering using 3D scanning for testing and analysis (especially making cross sections, determining volume, etc.), but I'm uncertain what kind of scanner we should obtain, or even if we should pursue that. I thought we needed a resolution of at least 0..03 mm, but I found it difficult to decide which is best suited for our use and or if we can afford the technology. More and more discs are transparent or have highly reflective surfaces these days, which I learned can cause difficulties in scanning. I understand that materials can be applied to the surface to permit a 3D scan, but I wouldn't want to do that for the PDGA test discs.

Your research sounds very interesting. I haven't read all the comments here or your research paper, but I need to when I have a chance. FYI, I'm an archaeologist, and I have training in classification theory, and one thing we're interesting in using the 3D scanning data for is for classification purposes. If interested, you should see the slides from my presentation at Masters Worlds last summer on tech standards . In the section on the future I added slides on 3D scanning. Here, I added 3D images collected on a major archaeological project in coastal LA. https://www.researchgate.net/public...resent_and_Future_of_PDGA_Technical_Standards

 

[Eric_T]

Thanks for that information. I've done all PDGA testing and approvals since 1989. We're now considering using 3D scanning for testing and analysis (especially making cross sections, determining volume, etc.), but I'm uncertain what kind of scanner we should obtain, or even if we should pursue that. I thought we needed a resolution of at least 0..03 mm, but I found it difficult to decide which is best suited for our use and or if we can afford the technology. More and more discs are transparent or have highly reflective surfaces these days, which I learned can cause difficulties in scanning. I understand that materials can be applied to the surface to permit a 3D scan, but I wouldn't want to do that for the PDGA test discs.

Your research sounds very interesting. I haven't read all the comments here or your research paper, but I need to when I have a chance. FYI, I'm an archaeologist, and I have training in classification theory, and one thing we're interesting in using the 3D scanning data for is for classification purposes. If interested, you should see the slides from my presentation at Masters Worlds last summer on tech standards . In the section on the future I added slides on 3D scanning. Here, I added 3D images collected on a major archaeological project in coastal LA. https://www.researchgate.net/public...resent_and_Future_of_PDGA_Technical_Standards

Oh, I just saw the video you did with Scott Stokely, very interesting!

3D scanning is definitely a big investment, both in $ and in time for learning the hardware and software. The manufacturers are usually very helpful with demos etc, so I would suggest that to figure out what works best. Something like the GOM Scan 1 could be interesting for a more automated setup, since you scan a similar object many times. For reflective surfaces, we use a scanning spray that adds a thin, matte, coating on the object. It evaporates after a while or can be easily cleaned off.

Cool to hear you have a background in archaeology. We collaborate with our archaeology department on 3D scanning, sharing equipment etc, they use it for documentation (see e.g. Arkeologisk Museum - University of Stavanger (@arkeologiskmuseum) ) Thanks for sharing the slides, always fascinating to learn more about the history of the sport. Although of course I think you should also include wind tunnel testing and simulations in your slides about the future

 

[Sheep]

Oh, I just saw the video you did with Scott Stokely, very interesting!

3D scanning is definitely a big investment, both in $ and in time for learning the hardware and software. The manufacturers are usually very helpful with demos etc, so I would suggest that to figure out what works best. Something like the GOM Scan 1 could be interesting for a more automated setup, since you scan a similar object many times. For reflective surfaces, we use a scanning spray that adds a thin, matte, coating on the object. It evaporates after a while or can be easily cleaned off.

Cool to hear you have a background in archaeology. We collaborate with our archaeology department on 3D scanning, sharing equipment etc, they use it for documentation (see e.g. Arkeologisk Museum - University of Stavanger (@arkeologiskmuseum) ) Thanks for sharing the slides, always fascinating to learn more about the history of the sport. Although of course I think you should also include wind tunnel testing and simulations in your slides about the future

Yeah, the 3d scanning stuff is like one of those investment purchases where you advertise farming it out to others to help recover the cost.

Cause we mentioned archeology... I'ma randomly throw in some stuff.


Ben sets a deal up to do some measuring with 3d scans on really old vases in this, and I believe there is some scanning footage as well. but. There are just limitations to what you can do.

You watch other scanning stuff and a lot of it is using reference dots, or things you can push a reflection with when scanning certian colors. I've seen where people use painters tape on everything to help the scan.
It's still an emerging technology.
And I think a lot of it comes to precision levels, and methods also. Because if we remember the ole XBox scanner hack with the camera. we were getting some pretty nice 3d scans with that. But the level of accuracy wasn't there.

 

[Eric_T]

Other candidates that would come mind here would be a Ti Buzzz (others have a more pronounced shoulder) vs. a Mako3 as those also have similar profiles but the Buzzz rim is concave while the Mako3 is convex/flat. The new FD also features a more concave rim.

What I wonder here is what the tradeoffs are in the design of the discs. Obviously the molds here are all very popular, achieving a similar purpose but are designed very differently.

I ran the River/FD comparison through my simulation setup now. Or rather, the Innova Dark Rebel, which is more or less the old Discmania FD mold as far as I have understood. I thought this was interesting as the Dark Rebel is one of my favorite discs I believe the River I have is more on the stable side, at least compared to what I read online. Also, neither the 3D scanning, the CFD simulation nor the trajectory simulator are perfect, so keep that in mind.

Here is a comparison of the flights, for a 56 mph throw:



I was surprised how similar they are! Looking into the details, it looks like the concave rim on the river is compensated by the more pronounced shoulder. So it looks like there are many ways to achieve similar results. If we look at other discs in Latitude 64's lineup, the Diamond has a very similar nose shape as the River. But the Sapphire, which was developed "to give [the Diamond] more speed and stability without sacrificing the glide", has a more standard shape of the nose.

The story behind Sapphire - Latitude 64

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www.latitude64.se

 

[HyzerRoc]

Thanks for doing that comparison thats really cool.

Not sure if I should be surprised or not. Going from the flight numbers they seem similar enough and fill a similar slot in a players bag. I would have expected that both would land in a similar spot, just that the River flys more of a curve to get there. Now I still wonder whether the different shapes make one preferable to one another aside from hand feel.

I also prefer the old FD/Hawkeye over the River btw

 

[isamoor]

The other difference between the River and FD is diameter. The River is one of the few popular drivers that is larger than the minimum diameter. I imagine that plays into the flight shape as well.

Discraft also has many drivers at larger than minimum diameter (stalker, passion, mantis, vulture).

I believe basically all Innova drivers are right at the minimum. They don't mess around with that dimension much for their drivers.