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 (http://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!! http://www.automags.org/ubb/smile.gif

[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.

[Eisaak]

I don't think it would be a huge cost factor. I think greed would make it a huge cost factor for the consumer but changing a mold from round to indented would not cost a ton. I do think that because a golf ball is solid it relies on the inside mass to hold its integrity but if you dimpled a paintball I wonder if it would hold together in flight. I bet someone is working on it somewhere. Or if they aren't they will start right after they read this.

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

[Trenon]

If anything I would make some just to find out the answer. Because if they do work someone will be making allot of money. If they don't work a big company loses like 1000 bucks. To a larg company thats nothing look at AGD's 35000$ giveaway for an example.

[Bearshirt]

<font face="Verdana, Helvetica, sans-serif" size="2">Originally posted by Eisaak:
I don't think it would be a huge cost factor. I think greed would make it a huge cost factor for the consumer but changing a mold from round to indented would not cost a ton. I do think that because a golf ball is solid it relies on the inside mass to hold its integrity but if you dimpled a paintball I wonder if it would hold together in flight. I bet someone is working on it somewhere. Or if they aren't they will start right after they read this.

</font>


Uh actually it would be a huge cost factor. I've made forming dyes before and they cost many tens of thousands of dollars! Think about it, you're not just milling a semicircle into the base metal, you're milling a semicircle with male dimples very hard to machine.

I read an article one on dimples of golf balls and due to the back spin when the ball is hit, the dimple creat lift.

[Eisaak]

_____________________________________________
[QUOTE]Originally posted by Bearshirt:
[B]
Uh actually it would be a huge cost factor. I've made forming dyes before and they cost many tens of thousands of dollars! Think about it, you're not just milling a semicircle into the base metal, you're milling a semicircle with male dimples very hard to machine.
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I was thinking a low tech approach. You don't need a metal cast for a gel ball. I bet most balls are made from a plastic cast. I don't make paintballs for a living mind you, but I just don't see the cost...... ok. the computer designing. The air tunnel flight testing...... I am sure you could waste a ton of money if you really wanted to. But I bet I could make them in my garage. They may not work worth a crap but I could make them! http://www.automags.org/ubb/biggrin.gif

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

[This message has been edited by Eisaak (edited 08-25-2001).]

[Trenon]

I'm not saying that it will kick right off the bat. Like anything this will need some R&D time just like anything else.

[rictus]

Here's how a paintbal is made straight from RPS.
http://www.rps-paintball.com/frames/birth.html

[Trenon]

If that is how a paintball is made it would be pretty cheap to test my theory. Alls they would have to do is make some male dimples on the 'Die Rolls'. They would not have to purchase all new machinery. It would pay for them to do some R&D.

[Eisaak]

I disagree..... the mold would be easy but the article says that the balls are hot and shrink as they cool. They are rolled slowly as they harden. How are you going to hold the dimples in place with this process. I just don't think this process allows for a dimpled ball. So now...... lets work on changing the process after the mold. We have a plastic mold with dimples..... now what? I was thinking we could make them like they use to make musket balls.... but I can see a lot of problems with that.

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

[Eye_pecking_chicken]

Why not just buy brasseagle paint that has hundreds of dimples on it =)

[Trenon]

I think that plastic mold idea could work but it all depends how hot the gelatin is when it goes into the mold.

[ShinyGuy]

I believe dimpled paintballs have been tried. Although the theory is valid once they're in flight the dimples need to be extremely consistent so as not to impart an unwanted spin on the ball. Right now the technology just isn't there to manufacture the balls well enough to work.

The other issue is that dimpled balls won't launch consistently out of a barrel. That turbulent air flow that is so great once the ball is in flight just makes launching the paint difficult.

BTW the theory behind dimples:
Most of the drag on a sphere in flight doesn't come from the air it has to push out of the way, it comes from the low pressure pocket created behind it as the air tries to fill the space the ball just left. The dimples disturb the air flowing over the surface so that it fills the space behind the ball faster. This greatly reduces that amount of drag behind the ball, however, if it is not done correctly the turbulence will push the ball of course.

The reason aircraft don't have dimples if that they are designed to bring the air together behind them in a controlled manor. Those long tapered edges prevent low pressure pockets from forming. In fact most aircraft do have turbulence generators in places where flat trailing edges can't be avoided (like around landing gear).

[ShinyGuy]

I'd also like to see what could be done with dimpling on Perfect Circle Paintballs. Since the shells are hard plastic I assume they're molded and since the shells are made without fill in them it might be possible to make the dimples consistent enough. Tom, care to try this? I'm still not sure you could fire a dimpled ball without problems but it would be interesting to know how close you could get.

[PyRo]

I belive AGD actually did test a dimpled paintball, and it didn't make any differance.

[martlet1]

Ok, the dimples on a golf ball are there for two reasons.
First, the impact of the ball against the club head. The golf club has lines etched into it, and when it meets the golf ball during the swing, it compresses the golf ball to about half of its shape, causing a spring effect on the ball, propelling it. The dimples on the ball add to the friction between the head and the ball, causing backspin, or topspin depending on the angle of the hit. It also causes nice slices to the left in my case.
Second, the dimple pattern makes for more or less spin depending on the amount and pattern. Not all golf balls have the same dimple pattern, generally the more dimples, the smoother the flight of the ball. The golf ball manufacturers are always debating the effects of the dimples.
I think the biggest way you could improve the paintball would be to add something to the interal part of the ball to make the weight distribute evenly inside the ball. I know when our team used to use nitro duck, they had so many different fills, it effected the flight patterns of the balls. Especially if it had sat in the warehouse for a while.


[This message has been edited by martlet1 (edited 08-27-2001).]

[Trenon]

Pyro you have any results of that test?

[fenris69]

AGD posted all of this a while back. turns out they dont do squat for pballs. wish i could recall the initial topic...might be able to search for it.

[Eisaak]

MARTLET1:
lets not ever bring up the subject of adding something to the inside! I love this sport but I dislike "Angel kisses". I have never cared much for getting shot. I'm thinking "more solid" is a very very bad idea. I would like to see them less solid.... almost like a summer mist on your skin. http://www.automags.org/ubb/biggrin.gif

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

[Hasty8]

One thing on the dimpled concept is that they are in a very specific pattern and not just willy-nilly. I remeber an article from a few years back that ight now, the dimples on a golf ball are just about at their max. No more can be added.

[auslandt]

Dimples might decrease drag, but it would cause problems elsewhere. Dimples
means more surface area and more "sharp" surfaces. Put dimples on a paintball
and you are likely to get them stuck VERY easily in the hopper. They will grab on the
way into the barrel and probably increase the load time. Then they might roll down
the barrel, but no longer. Dimpled paintballs would wobble, hop, bounce, and do
other friction type things that could throw off accuracy.

Golf balls, are loaded one at a time at about 1 per minute. Then once propelled by
the club, touch ONLY AIR. If golfballs had to be shot 10/second through a 2 foot
pipe by an air supply, they probably wouldn't have dimples either...

But then again Golfers that are within 40 feet of a target are happy... Show me
ONE paintballer that is willing to be that far off!! http://www.automags.org/ubb/smile.gif

[C¥borg]

I've shot golf balls out of guns before, ok it was a modified potato gun, and the golf ball couldn't travel down the barel without shaking the gun, or firing it. It worked pretty well, much more accurate than any potato could be, and I don't know if you guys have noticed, but golf balls tend to roll in straight lines pretty easy, I don't think there would be many feeding problems.

[PyRo]

Hmm, it either shot normally, or horribly. But whatever it did I know they didn't say it helped.

[M-a-s-sDriver]

Also remember that a golfball spins at around 10,000 RPM, and at that speed you can get dramatic differences in flight characteristics from a smooth ball. As you know, the Flatline barrels can flatten the trajectory of a smooth paintball noticably. Think of what you could accomplish with a dimpled paintball.
As for the benifits, the technology as we see it today is far more advanced than 10 years ago. I remember at a Nppl event in '94 seeing my first HP tank for paintball, and lots of people were Poo-pooing it as impractable for various reasons. Sounds silly now, huh? One of these days we will laugh at how we shot smooth paintballs, just like we laugh at oil-based balls. ...Well, that really wasnt a laughing matter, but you get the point.
Brent Jackson, PFB.

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Drink! for you know not whence you came, nor why. Drink! for you know not why you go, nor where.