[Compare] The Physics of why plastics have different stabilities

[seedlings]

...is what I'd like to read about. Do you know? Is it because of different coefficients of friction? Champion, as an example, seems 'slicker' than DX, but is more stable. I know that different plastic cools faster/slower, and that could deform the wing shape. Is that it? The shape of the mold changes, or is it just the plastic?

If two discs are molded identically, parting line height, wing shape, dome shape, weight, literally identical, except one is a premium plastic and another is a base plastic, would they still fly different stability?

 

[discerdoo]

https://www.dgcoursereview.com/forums/showthread.php?t=2250

Look up one thread^^

 

[GarrettDN]

...is what I'd like to read about. Do you know? Is it because of different coefficients of friction? Champion, as an example, seems 'slicker' than DX, but is more stable. I know that different plastic cools faster/slower, and that could deform the wing shape. Is that it? The shape of the mold changes, or is it just the plastic?

If two discs are molded identically, parting line height, wing shape, dome shape, weight, literally identical, except one is a premium plastic and another is a base plastic, would they still fly different stability?

The short answer is they would fly marginally different, but most of the variance is due to changes in shape. Things like weight distribution, subtle changes in surface friction and airflow disturbance, etc would create a very small change, but most is due to shape-based changes, even when new.

 

[Karl]

...is what I'd like to read about. Do you know? Is it because of different coefficients of friction? Champion, as an example, seems 'slicker' than DX, but is more stable. I know that different plastic cools faster/slower, and that could deform the wing shape. Is that it? The shape of the mold changes, or is it just the plastic?

If two discs are molded identically, parting line height, wing shape, dome shape, weight, literally identical, except one is a premium plastic and another is a base plastic, would they still fly different stability?

The shortest answer to your last Q is "yes".
A not-quite-as-short answer is "NO two discs are 'identical'" (literally or otherwise) and thus will always fly (each) uniquely. As to HOW different any two will fly (comparatively) is determined by which parameters are 'different' and by how much.

 

[elmexdela]

mfers on here cant even on agree on why discs fly differently in the cold temps how tf do you think they finna know this

 

[runningDoc]

https://youtu.be/By0CFQwVUT0

 

[seedlings]

https://youtu.be/By0CFQwVUT0

Yep. I have watched that one some time back. That's why I asked if two discs were 'identical' in every measurable way, but different plastics, would they fly the same. I think the answer is 'yes'. And the reason different plastics have different stability is because of PLH and dome, because of how they cool. If so, that means base plastics always cool with a lower PLH.

 

[Flick Maniac]

Find two discs identical in shape, but one in DX and one in Champion, and I guarantee they fly 99% the same. Slick Champion may microslip a little earlier out of the hand, creating some difference. But the effect of surface texture alone vs the air, when new? Likely miniscule.

Obviously changes will soon appear the more they get thrown. Likely more due to the PLH being bent downwards from hitting the ground and obstacles. Nicks, gouges etc creating more turbulence? Again, likely pretty miniscule.

 

[Jacobpaul81]

Yep. I have watched that one some time back. That's why I asked if two discs were 'identical' in every measurable way, but different plastics, would they fly the same. I think the answer is 'yes'. And the reason different plastics have different stability is because of PLH and dome, because of how they cool. If so, that means base plastics always cool with a lower PLH.

Similarly - if two discs are made of the same plastic but at different times, you will see variance in flight - because their shape will vary. Any company that says they can be "consistent" from run to run - is lying.

 

[runningDoc]

i think in a vacuum with no damage and same exact weight measurements discs will fly the same.

but even after one throw dx plastic (or other baseline plastics) get nicked quickly changing stability.

there are instances where even baseline plastics produce ridiculous level over stability like the steego and the tilt.

and other times you'd think premium plastic versions are going to be more over stable but aren't. many have reported that original pro plastic terns were very over stable even more so compared to champion versions. but it was pro plastic so would beat in quickly.

 

[armiller]

It's easy to over-think this kind of thing. If the dimensions are the same (assuming densities/mass are the same as well), the physics should be the same prior to the differences in wear.

But therein lies the rub. This is an injection molding process and already varies enough from disc to disc with the same mass and plastic. Change the plastic being injected, and it will be very difficult to achieve a DX or Pro or Star or Champion (or [insert non-Innova plastic types here]) that flies like any disc in a different plastic. Now add the different wear patterns for all these discs, and they not only fly differently but also have very different lives.

TLDR: Different plastics don't change the physics. Injection molding is an imperfect (though awesome) process that involves a certain level of unpredictability. That is even more apparent when comparing between different plastics.

 

[bnrstnkr]

Two discs will always fly differently. Different plastics have different densities. If two discs were identical in size and shape in all ways, but were from two different plastics, the one made from denser plastic would weigh more, and fly differently due to increased inertia etc.

 

[JuanA]

If you have a stack of identical discs that all fly the same, they'll only stay that way if you don't throw them.

I understand the quest for knowledge, but for something that changes so much during its playable life is it worth worrying about?

 

[Countchunkula]

It's easy to over-think this kind of thing. If the dimensions are the same (assuming densities/mass are the same as well), the physics should be the same prior to the differences in wear.

But therein lies the rub. This is an injection molding process and already varies enough from disc to disc with the same mass and plastic. Change the plastic being injected, and it will be very difficult to achieve a DX or Pro or Star or Champion (or [insert non-Innova plastic types here]) that flies like any disc in a different plastic. Now add the different wear patterns for all these discs, and they not only fly differently but also have very different lives.

TLDR: Different plastics don't change the physics. Injection molding is an imperfect (though awesome) process that involves a certain level of unpredictability. That is even more apparent when comparing between different plastics.

I don't know that I really buy that it is impossible to make consistently shaped discs. I think the issue is that the manufacturers don't have any incentive to make the investments needed to hold tighter tolerances.

 

[seedlings]

I don't know that I really buy that it is impossible to make consistently shaped discs. I think the issue is that the manufacturers don't have any incentive to make the investments needed to hold tighter tolerances.

Imagine if every Destroyer flew identical. All the mystery and legend would be eliminated! No more 'Calvin 2020' or 'Ricky Robot' nostalgia. Company makes a bunch of discs. Pops them out still hot. Stacks them in a tower... the ones on the bottom cool slow with smashed wings and are understable. The ones on top cool faster, more stable.

Spoiler

I agree with you though. Leave the discs in the mold longer to cool? It's impossible that there hasn't been some staff meeting where this conversation hasn't happened. It's either impossible, undesirable, or cost prohibitive.

 

[Countchunkula]

Imagine if every Destroyer flew identical. All the mystery and legend would be eliminated! No more 'Calvin 2020' or 'Ricky Robot' nostalgia. Company makes a bunch of discs. Pops them out still hot. Stacks them in a tower... the ones on the bottom cool slow with smashed wings and are understable. The ones on top cool faster, more stable.

Spoiler

I agree with you though. Leave the discs in the mold longer to cool? It's impossible that there hasn't been some staff meeting where this conversation hasn't happened. It's either impossible, undesirable, or cost prohibitive.

The bolded part is what gets me. The company I work for molds small plastic gears. The tolerances on most of the dimensions are .005". The gears drop out of the molding machines into plastic bins and the operators cycle around and empty them when they are full. We don't give much consideration to cooling outside of the machine and still meet a pretty tight tolerance. Maybe that's due to the much smaller size, but still.

 

[seedlings]

The bolded part is what gets me. The company I work for molds small plastic gears. The tolerances on most of the dimensions are .005". The gears drop out of the molding machines into plastic bins and the operators cycle around and empty them when they are full. We don't give much consideration to cooling outside of the machine and still meet a pretty tight tolerance. Maybe that's due to the much smaller size, but still.

I hope it's obvious, but just in case, that was a total wild guess I made, not based on knowledge at all.

 

[Countchunkula]

^Your wild guess is pretty much the same as the message board consensus afaik. People on here usually point to the cooling process as the source of variation in discs of the same mold and plastic.

 

[captain jack]

You only need to understand two things, metal salts, and parting line height.

 

[oldmandiscer]

The bolded part is what gets me. The company I work for molds small plastic gears. The tolerances on most of the dimensions are .005". The gears drop out of the molding machines into plastic bins and the operators cycle around and empty them when they are full. We don't give much consideration to cooling outside of the machine and still meet a pretty tight tolerance. Maybe that's due to the much smaller size, but still.

From what I've read the plastic used for discs will shrink after cooling and the difference is dramatic. I believe Champion style shrink the least while Base plastics like DX shrink the most. Then you have different thicknesses between the flight plate and rim so obviously the plate will cool faster. There are a lot of factors involved.

Just to confirm I measured two Beasts. The DX feels skinnier then the Champion and is substantially.

DX- 1.98 rim width

Champ- 2.04

It's basically a different disc at that point just from how much that plastic shrinks then of course the PLH and dome differences as well as well as overall width and depth.