Theoretical Paintball

[Trenon]

I have a question wich may have been asket before but I am not sure. Why is a paintball suppost to be round? Why round? Why not a square or a bullet shaped thing? Is it for areodynamics no. Because if it was for areodynamics people would have looked at another very popular sport. Golf.

The golf ball started off round. But it was discoverd that a round object creats a fair amount of drag behind it since it pushes its way through the air. But someon discoverd that by putting little dimples in the ball would disturb the air around the ball hence minimizing the drag produced by the ball.

So I wonder why are paintballs round. I am just a17 year old kid with by no means the time, supply or means to test this idea but Tom you may want to look into this. I know it would cost more to make paintballs with dimples but if they go farther with greater acuracy people will buy them.

If I was allowed to talk in Deep Blue I would have brought this to more peoples attention but since I am not this forum will have to do. I hope my thoughts are helpful and helpl create a better paintball.

[X-Plosive]

Well I imagine that putting dimples in a paintball may help. What problems would you run into? Maybe feeding issues?

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Taking mags apart is fun, its even more fun when you don't know what you're doing

Ohh yeah and Tunaman sorry for all the stress and all the things I've broken.

*If corn oil is made of corn, what is baby oil made of?*

[AGD]

they are round because they are easy to make and feed by gravity. Dimples do not make things fly farther, otherwise jets would have dimples. We make bullet shaped paintballs for the military that are more accurate but they only have 15 shots in a clip.

AGD

[j_gets]

Jets are elongated though, not roughly spherical, so dimples shouldn't have an effect. Dimples reduce drag on a spherical object through turbulence. Remember a couple years back when they started changing the patterns of dimples in golf balls and got them to go a bunch farther?

Please read the following, obtained from www.howstuffworks.com

Question

Why do golf balls have dimples?

Answer

The reason why golf balls Have dimples starts with natural selection. Originally golf balls were smooth, but golfers noticed that older balls that were beat up with nicks, bumps and slices in the cover seemed to fly further. Golfers, being golfers, naturally gravitate toward anything that gives them advantage on the golf course, so old, beat-up balls became standard issue.
At some point an aerodynamicist must have looked at this problem and realized that the nicks and cuts were acting as "turbulators" - they induce turbulance in the layer of air next to the ball (the "boundary layer"). In some situations a turbulent boundary layer will reduce drag.

If you want to get deeper into the aerodynamics, there are two types of flow around an object: laminar and turbulent. Laminar flow has less drag, but it is also prone to a phemonena called "separation". Once separation of a laminar boundary layer occurs drag rises dramatically because of eddies that form in the gap. A turbulent boundary layer has more drag initially but also better adhesion, and therefore is less prone to separation. Therefore, if the shape of an object is such that separation occurs easily, it is better to turbulate the boundary layer (at a slight cost of increased drag) in order to increase adhesion and reduce eddies (a significant reduction in drag). Dimples on golf balls turbulate the boundary layer. The dimples on a golf ball are simply a formal, symetrical way of creating the same turbulence in the boundary layer that nicks and cuts do.


Maybe someone should do some r&d on dimpled paint. Great post Trenon.

Josh

[This message has been edited by j_gets (edited 08-24-2001).]

[Trenon]

This one needs an up.

[Trenon]

In reply to the comment that dimples do not make things fly further that isn't true. They actually do. Tom you are comparing 2 different things here a jet has a means of propulsion, and it cuts through the air. A paintball has to ride the initial force of being fired out of a paintball marker.

The reason a jet doesn't have dimples is because the shape of it compensates its drag. But a paintball has no composation feature or it would look like a sideways raindrop. I am almost certain that dimples would improve the flight of the paintball and give it greater distance from the same amount of force.

[Eisaak]

in response to cphilip:
I agree, I don't think it would go that much further but i do think it would greatly reduce the effects of drag on the ball at the end of flight. Balls slice to one side or the other at the end of their arc. I bet the dimples would give the ball a much straighter line. It would most likely buy you an extra couple of yards and a much smaller strike diameter.

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"I am the adversary."
-Eisaak (me)-

[cphilip]

But ya know from a marketing thing... even if it didn't do a single thing... you guys might be right. If you could make em believe it was soooo much better! Then you could sell a million of them!

[Trenon]

It must make a NOTICIBLE difference, my evidence is this; Have you ever seen a round golfball? If they wee cheap people would buy them but still they go for the more expensive dimpled balls. Therefore there must be a noticible difference.

[Sgt Carnage]

It's possible. But keep in mind golf balls are structurally different. And they are propelled by a violent impact with a metal or wooden club. A paintball with dimples propelled by air might not react the same. Air may just pass around it easier or too easy.
Maybe they have already experimented with them who knows.
Anyway, interesting thread to say the least

[ben_JD]

There is a similar phenomenon with more dense liquid (e.g., water) that researchers have found. Specifically with a shark's skin, the rough, toothy surface allows the energy output necessary to keep moving through the water to be reduced significantly. Thus, the new swimmer's wear that was banned in many pre-onlympic competitions that incorporated the theory in the new fabric. The effect is not insignificant, but I wonder to what degree it would work with paintballs.

I think some experiments are in order. (I do wonder where I left that paintball dimpling machine...perhaps in my attic).

-Ben

[THOR_MAG]

Actually some Jets have kind of "dimples"!!
ok they don't have dimples but there is research done with special foils on wings of airplanes that create a turbulent boundry layer because of roughnesses. comparing to smoth surfaces this wings have lower air resistance. I think there is a good chance that dimples could create a turbulent boarder layer around the ball that decreases its air resisance and increase the travel distance with a given amount of starting energie. But the generall shape has on the drag coefficient is much bigger. It would therfore make more sense to change the generall shape of the paintball than putting dimples in(http://www.grc.nasa.gov/WWW/K-12/airplane/shaped.html) which means the production would be way more expansive you need other ways to get the bullet in the chamber and so on.
and finally if they would change the shape we would have to change the name of this great sport from paintball to paintbullet!!

[cphilip]

Take one part out of context and see where it leads you? First part of Tom response was, in fact, the most important one. So I will do the same. Quote: "they are round because they are easy to make...". Now stop right there. Any increase in distance, theoretical or not, would be so slight that the *enormous* increase in cost to try and manufacture them with even patterns of dimples would never return enough noticeable improvement to justify it.

[This message has been edited by cphilip (edited 08-24-2001).]

[THOR_MAG]

To manufacture them with dimpeles wouldn't cost more once it is established. You would just have to change the form of the mold for the shells. It's just that you wouldn't get a big effect just by putting dimples in!!

[cphilip]

These things don't even stay round and you say the dimples will stay uniform? I seriously doubt it and remember I said the gain would be so slight you probably wouldn't even notice it. And I believe you understimate the cost of retooling for this.