Barrel Efficiency, Tech Tip #1

[SniperWolf]

glass barrels eh? take a look at the new pirhana barrel, clear. theyre made out of polycarbonates i believe, like bullet proof glass. now about this effective length, i understand that porting makes it less gas efficient, but does the porting really vent all the accelerating gas that early? wouldnt the severity of the porting also dictate effective length. like the 98 barrel, it has a ring of porting very early on, but is that venting area enough to blow off all that gas i dont think so. and the palmer theory, palmer is a very smart guy, but their is video where someone powdered the barrels and shot through it, and showed that a paintball rides on the 2 highest points, like rails. so palmers spoken like a man who doesnt makes different bore barrels. though he does have elliptical honing, which is a whole other barrel of monkeys

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Frag'd, toe tagg'd and body bag'd,
hell son, you mustve just been automag'd

[hitmanng]

Jerk is a mechanical term for a specific aspect of motion: the rate of change of acceleration with time or in this case ft/sec/sec/sec. I do not believe that is what Tom is using.

Velocity is defined as the rate of change of position with time, and measured in paintball as feet per second.

Acceleration is the rate of change of velocity with time; acceleration is measured in paintball terms in feet per second per second.

Jerk describes the way acceleration itself changes; it is reckoned in the even more unwieldy units of in paintball terms feet per second per second per second.

A paintball accelerates from 0 ft/sec to 300 ft/sec over 0.83 ft if the rate of acceleration were 50,000 ft/sec/sec the time period would be 0.006 seconds
That's 300ft/sec / 50,000 ft/sec/sec = 0.006 sec
The acceleration of gravity is 32 ft/sec so That's 50,000 / 32 = 1562.5 G
I believe those are the numbers used by Tom above.
Tom is using acceleration here and simply forgot or figured most wouldn't understand or care about the units used. I know I didn't care as it was not needed to understand what he was trying to say.

Last week Phase chemistry, this week physics. Maybe next week we will look into molecular biology. Maybe Organic chemistry study up on your function groups.
Tom Kayes paleantologist, astronomer, enginer and physicist.
Now right now Army is going. Wow all that and he cannot even spell. LOL
Hitmanng


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"I would rather hit once than miss 140 times."

[DarkPhoenix]

Porting also helps the paintball in its movement through the barrel. The porting helps bleed off the air in front of the pball as it moves forward, because the paintball also has to deal with the pressure of the air in front of it, in an non-ported barrel, I believe the air in front gets a little compressed and the paintball must overcome this pressure, so porting and the barrel break help in this regard. I may be complete off base here, but I believe that these are other factors that come into play when considering barrels, as non-ported barrels are usually louder but more gas efficient, while ported barrels tend to be quieter, less gas efficient and, some say, more accurate. It is my personal belief that this accuracy is obtained by the effective venting of the pressure both in front and behind the ball. Though, I have been known to be wrong before....

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RT Pro P/F
w/ AGD Flatline

[RobAGD]

Actually Tom has high speed vidoe of that.

There is nothing being pushed out the end of the barrel by the ball. It was long held that the ball would be pushing a colum of air out BEFORE it exited the barrel.

Toms high speed video shows that the onlt thing exiting the barrel is the Ball then a gas plume. The Smoke was intact until the ball broke its plane.

-Robert

[MajorDamage]

PORTING! Porting also helps with ACCURACY! Imagine shooting a bullet into the water, it just curves like crazy and stopps. Its thesame with paintballs pretty much. But the holes in the barrel slowly get the paintball used to the air, helping it to not just be suddenly introdued into the air. SO THATS WHY PORTING IS GOOOODA!

ENDO!

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My Battle cry!
Spoon Spork Purple Monkey Dishwasher Hoo Ha!

[SHAG]

Hi,

The fellow above does have a point and I would like Rob or Tom to elaborate this in more detail. I remember in the AGD video that Tom discussed the "new" Crown Point barrel. He was mentioned it ressembled the V ducts on Indy cars. Also it was to aid the ball with a smoother transition into the air. What happened with the CP barrel design? Other than that, Tom, Glenn, and Colin have alot of time in barrel design. I feel they are on track when it comes to the barrel. The best barrel design that does mix the effective barrel length and porting is the J&J Ceramic. It is the best of both worlds.

Later,
Alan

PS Nice to see on here Jeb

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Paintball cannot be that big. No one has really been able to sponsor a stock car or a race yet. (local people do not count in this case )

[klm5]

Thanx for the info, I'll do some side-by-side comparison shooting with my AA & shorter, un-ported Armson.

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68PF,Boo-Yaah frame,SP AA 14",Shocktech cradle

[hitmanng]

You have to remember the speed of travel, and excelleration here. The ball is moving faster than the air could "Move out of the way". Playing in a vaccum would be great but not an option. The Idea of the crown point was to create a gradual transition from the air in the barrel to the air outside the barrel. I think it never took off because with all of the forces on the ball the crown point was not he most important factor. Do you realize that we can hit a can with a gellatin paintball, filled with fluid, 50 ft away, being propelled by air. That is a remarkable feat. I think asking for much more is too much. The fact is you can do this with most barrels. No new designs can overcome all of the uncontrolable factors.
Hitmanng


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"I would rather hit once than miss 140 times."

[Webmaster]

Manike -

Sorry for the later reply

Yes - it is Mister.44

cheers!


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Webmaster - AutoMags.Org
[email protected]
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"Good...bad...I'm the guy with the gun." - Ash, Army of Darkness

[The Taoist]

Great post tom. Very helpfull information. webmaster (aka Mister.44), just wanted to let you know that i enjoy you reviews / articals in APG. Good work guys!!

[randomboy]

Its amazing what you can learn just sitting here at the computer

[manike]

Cool good to see you

I guess things worked out then!

Gonna be at the Cup this year? I'll be over for it again

manike

[randomboy]

Oh yeah, and damnit, I completely missed hitmanng's thread yesterday, then thought of that answer while at work today 50,000/.006 = 300

I slapped myself in the head for not realizing it sooner. haha. And to think I just got out of physics class a month ago, what a shame.

[PyromaniaX]

so what about ram rods? That would make them have like 1 inch of effective barrel.

[M-a-s-sDriver]

Well, I've been thinking about this, and the conclusion I come to is that there painty-ball thingy Does not, cannot, would not, and is completely unwilling to go 50,000 feet per second, no matter how much to beg. The problem with the formula (50,000 x.006 =300) is that you are assuming the paintball travels 300 feet in .006 seconds, because that is how fast it would have to go in that amount of time to hit 50,000 fps. A mile is 5280 feet. For this logic to work, it means that poor little paintball has to go 2840 miles per hour. That is approximatly mach 4. That is the muzzle velocity of a .308 sniper rifle. (ARMY, step in here if my ballistics are wrong buddy). A paintball has a muzzle velocity closer to an arrow released out of a 70# bow.
Now, If that ball got anywhere NEAR 50,000 fps, you would have to decelerate the poor thing back down to 300 fps somewhere in the barrell. Unfortunatly, all the two piece extremme porting in the world won't do that.
Sorry guys. The math is wrong here. Think about it some more and you will see.
Respectfully, Brent Jackson, PFB.