[Innova] CHAMPION VS STAR

[Rameka]

Maybe you're actually rubbing off a very thin layer of disc with the eraser and it takes the ink with it? Kind of like how you can erase ink from a textbook's page.

That's actually a decent theory as well. Some people do refer to their base plastic discs as "chalky". Good call

 

[solomon.trenton]

Maybe you're actually rubbing off a very thin layer of disc with the eraser and it takes the ink with it? Kind of like how you can erase ink from a textbook's page.

or it could just be that champ and star absorb the ink deeper into the plastic

 

[Three Putt]

As much as I respect you and love reading your posts, I'm going to have to disagree with some of what you've said.
A higher dome means that there is a larger pressure gradient between the top and the bottom of the disc. This means a disc with a dome will act more understable. The air over the top of the disc will differ in speed from port to starboard; the air over the top surface of port (for a RHBH throw) will be going faster relative to the surface of the disc than the air over starboard. Since the air on the underside of the disc won't differ much from port to starboard (the inside pocket under a disc is what creates the vacuum that produces lift), the dramatic difference in speed won't cancel out (The common, and incorrect, counter argument here is that since there's a ratio between the air going over the top surface and the bottom surface, it won't matter if the air going over/under the port surface differs from the air going over/under the starboard surface because their ratios cancel out...kinda like how 1/2 = 2/4. However, this is incorrect because of the vacuum I mentioned.). So, the domier disc will be more understable. A dome will always have that effect. If you've experienced otherwise, it would have to be for some other reason than dominess: perhaps some other aspect of the geometry of your discs. This seems strange to me, because I'm aware of the fact that you've thrown hundreds of discs. It's confusing to me that you noticed such a trend...

This reminds me of college. I had a roommate that was an engineer, he used to talk over my head all the time. I'm pretty sure he was making most of it up.

I have no idea how this works. I just know a flat Roc is more stable than a domey Roc but a domey Boss is more stable than a flat Boss. If I was forced to guess I'd say that two discs from the same mold that have different dome sizes probably have different nose angles, it's just easier to notice the dome. The different nose angles would effect the air going over and under the disc I would guess. I don't know, just grasping at straws.

 

[Omega SuperSloth]

This reminds me of college. I had a roommate that was an engineer, he used to talk over my head all the time. I'm pretty sure he was making most of it up.

I have no idea how this works. I just know a flat Roc is more stable than a domey Roc but a domey Boss is more stable than a flat Boss. If I was forced to guess I'd say that two discs from the same mold that have different dome sizes probably have different nose angles, it's just easier to notice the dome. The different nose angles would effect the air going over and under the disc I would guess. I don't know, just grasping at straws.

not trying to be a di** im just interested in what your saying but im not sure what you mean by more stable, do you mean the roc becomes more stable (meaning less overstable) or do you mean it becomes more overstable?

 

[solomon.trenton]

This reminds me of college. I had a roommate that was an engineer, he used to talk over my head all the time. I'm pretty sure he was making most of it up.

isnt this how it always works?

 

[Midnightbiker]

Some discs work better in different plactics. I prefer the Champ Valk over the Star Valk

 

[sidewinding]

I have a theory:

One of the easiest cars to roll over is an old Volkswagon Beetle. The reason is because of all the round surfaces. For some reason air can grab onto a round surface much more efficiently than a flat surface and create lift and drag. They say that a beetle going 70 MPH is about 4" higher than the same beetle at 0 MPH.

So a domier disc has more drag and lift which slows it's spin and makes is reach the LSS portion of it's flight faster making it appear to be more stable.

For me Star plastic is more stable because I cannot grip it as good as I can Champion plastic. Bad grip equals less spin which equals more stable. Some folks can grip Star better than Champion.

 

[Three Putt]

not trying to be a di** im just interested in what your saying but im not sure what you mean by more stable, do you mean the roc becomes more stable (meaning less overstable) or do you mean it becomes more overstable?

I meant more overstable.

 

[Three Putt]

As much as I respect you and love reading your posts, I'm going to have to disagree with some of what you've said.
A higher dome means that there is a larger pressure gradient between the top and the bottom of the disc. This means a disc with a dome will act more understable. The air over the top of the disc will differ in speed from port to starboard; the air over the top surface of port (for a RHBH throw) will be going faster relative to the surface of the disc than the air over starboard. Since the air on the underside of the disc won't differ much from port to starboard (the inside pocket under a disc is what creates the vacuum that produces lift), the dramatic difference in speed won't cancel out (The common, and incorrect, counter argument here is that since there's a ratio between the air going over the top surface and the bottom surface, it won't matter if the air going over/under the port surface differs from the air going over/under the starboard surface because their ratios cancel out...kinda like how 1/2 = 2/4. However, this is incorrect because of the vacuum I mentioned.). So, the domier disc will be more understable. A dome will always have that effect. If you've experienced otherwise, it would have to be for some other reason than dominess: perhaps some other aspect of the geometry of your discs. This seems strange to me, because I'm aware of the fact that you've thrown hundreds of discs. It's confusing to me that you noticed such a trend...

This reminds me of college. I had a roommate that was an engineer, he used to talk over my head all the time. I'm pretty sure he was making most of it up.

I have no idea how this works. I just know a flat Roc is more stable than a domey Roc but a domey Boss is more stable than a flat Boss. If I was forced to guess I'd say that two discs from the same mold that have different dome sizes probably have different nose angles, it's just easier to notice the dome. The different nose angles would effect the air going over and under the disc I would guess. I don't know, just grasping at straws.

Even a blind squirrel finds a nut once in a while. From the "Ask Dave D" thread on the PDGA page:

Generally, dome is an indication of too much shrink, but not always. Generally, I would expect a domey disc to be less overstable than a flatter disc. Dome actually helps straight line stability, (not over stability). However, when it is an artifact of too much shrink, the nose angle can be changed adversely, which can affect high speed stability.

Which makes sense since the shrink on a rounded nose disc like a Roc probably will not have a big effect on the nose angle and the dome effect would stay true. The angle on a sharp-nosed driver like the Boss could be dramatically altered and that could override the effect of the dome.

At any rate, that's my story and I'm sticking to it because...well, because I'm in over my head and have no idea what I'm talking about. But it sounds good, doesn't it?