Barrel tech question

[sabrefanpc]

I'll admit it- I know far more about cars than paintball guns. So here's where im goin with this, when an engine is ported to increase airflow, the surface is not pollished but small dimples cover the surface. air flows better over the dimpled surface, as an air cushion forms around the piping walls instead of rubbing against the polished walls. why then do i hear of barrels being polished? are barrels made with auto style port/polish jobs?

[bjjb99]

I'll admit it- I know far more about cars than paintball guns. So here's where im goin with this, when an engine is ported to increase airflow, the surface is not pollished but small dimples cover the surface. air flows better over the dimpled surface, as an air cushion forms around the piping walls instead of rubbing against the polished walls. why then do i hear of barrels being polished? are barrels made with auto style port/polish jobs?

Dimpling is done to increase turbulence in the air flowing over a surface, which tends to reduce airflow drag. Inside a paintball barrel, you're not concerned about how smoothly the air flows through the barrel, you're concerned about how smoothly a paintball travels down the barrel. I know of no port/polish/dimpled barrels.

BJJB

[Mister Sinister]

Well the short answer to your question is. The polished barrel reduces friction between it and the ball. Their is a difference when your talking about friction between a solid surface against a gas versus a solid surface against a solid surface. The boundary layer effect only applies to gasses. Even then a description of their being a cushion isnt quite accurate sorta... a better one is that airflow in a port is comprised of layers moving at different speeds.

[sabrefanpc]

ok i see what your sayin. would a dimpled barrel have redeeming qualities to outway the increased drag on the ball? (ie quiter, no blowback into hopper, etc)

[hitech]

There is an entire post at the top that discussing dimpled paintballs. All your questions should be answered there.

[armyballer]

There is an entire post at the top that discussing dimpled paintballs. All your questions should be answered there.

umm not to like be a jerk but he is asking about dimpled barrels i kinda got a the drift of what he is askign but im jsut a grunt i got no clue

[wolfwood_is_here]

ok, it is true we are talking about a solid vs. solid surface, but have any of you read the topic under "Toms Tech Tips" about barrels and paintballs, where realistically you only want the equator (seam) of the paintball to be touching the barrel, becuase it is the biggest part of the paintball. Otherwise, you are forcing a painball into a small area, and thus putting a lot of force in the form of friction on the paintball.

I do realize that the article is not brand new, but if you could get the air flow between the paintball and barrel to be normalized, you might also reduce "bouncing" inside the barrel beause of small bore paint not having an even flow of gases behind it. Most likely you would not port that barrel in order to prevent the gases from escaping too quickly.

so possibly, this type of barrel would be best used with smaller bore paint? I dunno, I guess you would have to try and make one to see what happened. Please correct anything I have said if it is not so...

[Miscue]

It's because airflow in the barrel is not an issue - the ball stays ahead of the air blast - it gets popped out like a cork from a bottle. You want it smooth so it cleans easier and has less friction between the ball and barrel, slowing it down.

[wolfwood_is_here]

so when a paintball is too small, no air ever gets past it?

I do see the error in my thinking. If there is no air getting past the paintball, then it should not matter. If there were some way to keep the paintball and the air in the barrel concentrated towards the center, then it would seem (theorhetically) be less wobble in the barrel. I guess that would be kinda hard, however, unless you engineered a way for the barrel to adjust for every single paintball...

[Miscue]

so when a paintball is too small, no air ever gets past it?

I do see the error in my thinking. If there is no air getting past the paintball, then it should not matter. If there were some way to keep the paintball and the air in the barrel concentrated towards the center, then it would seem (theorhetically) be less wobble in the barrel. I guess that would be kinda hard, however, unless you engineered a way for the barrel to adjust for every single paintball...

Why would it be wobbling in the barrel?

Why does the barrel need to dynamically adjust to each paintball? What problem does this solve?

[Lurker27]

perfect paint to barrel match, every time. Of course, the nature of the shell, gives us a margin of error of a few thousandths, so I would just run one of each lapco barrel and never worry about accuracy again.

[wolfwood_is_here]

if the barrel could dynamically adjust itself to match the bore of every individual ball, you won't get bounce, your air efficiency would be greater, and thus you would get more shots and each shot would be more consistent because the balls would be coming out of the barrel the same way each time. Why else would there be such a rave for barrel to ball bore matching if it made no difference? Why have removeable inserts if having one stady bore is fine?

[Miscue]

if the barrel could dynamically adjust itself to match the bore of every individual ball, you won't get bounce, your air efficiency would be greater, and thus you would get more shots and each shot would be more consistent because the balls would be coming out of the barrel the same way each time. Why else would there be such a rave for barrel to ball bore matching if it made no difference? Why have removeable inserts if having one stady bore is fine?

But the ball dynamically shapes itself to the barrel. If it's slightly off, doesn't matter because it will give a bit. If the sample balls are not touching both walls: You are using too large of a barrel, or you have really crappy paint with large varience between balls. Good paint is pretty consistently shaped, and this becomes a non-issue.

I think you're proposing solutions to problems, that aren't problems.

[Miscue]

Oh, also there is already a gap. Only the equator of the paintball touches the walls, and there is already a way for air to go past the ball. The paintball never created a perfect seal in the first place.

Also, the "gap" diagrams are exaggerated by a lot. Even bad paint won't be off that much.

[wolfwood_is_here]

first off, in a perfect ball to barrel match, the equator alone would touch. If you don't have that perfect match (like many rec players) then it may be more of a gap or it may be less. that is part of the whole reason of matching barrels to the correct paint.

ok. I was showing what happens, so sometimes exaggeration for the sake of understanding a concept is neccesary. If it really throws off the idea, I am sorry.

Yes, paintballs do adapt themselves. But not every two paintballs are exactly the same in every respect. Yes, they are very very close, and are closer now than they have been. But they are not the same precision as real bullets, where you can have the same sized barrel and the ammo of your calibur will all fit through it. Not too many marines swapping barrel inserts when they get a new shipment of ammo.

What I was proposing was instead of depending on the paintballs to adapt, that the barrel would do it for you. Variances of even .01 between the paintball and barrel can mean a difference in the paintballs behavior in the barrel. Think of when you have an old school diver, and his glass helmet gets a crack, just a crack in it. The air leaks out. The "gap" in his helmet is of a very small size, yet air still found a way because of a presure difference.

So, instead of adapting the paintball for the barrel, we would adapt the barrel for the paintball, every single one to maximize consistency and efficiency. That way, no matter what diameter you put in, the barrel would adapt. If there were inconsistencies in the paint, the barrel would accomodate. Even the slightest tightening of tolerances can sometimes have very drastic effects. But I won't know till something like this is created and the statistics can be compared, so really at this point it is guessing.