# Barrel Efficiency, Tech Tip #1

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• 06-23-2001, 01:08 AM
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 http://www.automags.org/ubb/tongue.gif

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Frag'd, toe tagg'd and body bag'd,
hell son, you mustve just been automag'd
• 06-23-2001, 04:08 AM
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."
• 06-23-2001, 05:37 AM
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
• 06-23-2001, 01:42 PM
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
• 06-23-2001, 07:43 PM
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!
• 06-23-2001, 08:27 PM
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 :))
• 06-23-2001, 09:15 PM
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
• 06-23-2001, 09:20 PM
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."
• 06-24-2001, 08:19 AM
Webmaster
Manike -

Sorry for the later reply

Yes - it is Mister.44

cheers!

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Webmaster - AutoMags.Org
webmaster@automags.org
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"Good...bad...I'm the guy with the gun." - Ash, Army of Darkness
• 06-24-2001, 12:58 PM
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!!
• 06-24-2001, 01:17 PM
randomboy
Its amazing what you can learn just sitting here at the computer http://www.automags.org/ubb/wink.gif
• 06-24-2001, 04:10 PM
manike
Cool good to see you http://www.automags.org/ubb/smile.gif

I guess things worked out then!

Gonna be at the Cup this year? I'll be over for it again http://www.automags.org/ubb/wink.gif

manike
• 06-25-2001, 03:50 PM
randomboy
Oh yeah, and damnit, I completely missed hitmanng's thread yesterday, then thought of that answer while at work today http://www.automags.org/ubb/wink.gif 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.
• 07-20-2001, 10:31 PM
PyromaniaX
so what about ram rods? That would make them have like 1 inch of effective barrel.
• 07-20-2001, 11:30 PM
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.
• 07-20-2001, 11:51 PM
keebler
well actualy chuck at co paintball in toledo ohio showed me a pic of this 3 foot (i think it was that long) barel he messes around with his angel. lol, that thing might do the job.
• 07-21-2001, 01:02 AM
hitmanng
Quote:

<font face="Verdana, Helvetica, sans-serif" size="2">Originally posted by 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.
</font>
Sorry M-a-s-sDriver,
But you have your units wrong here. The ball does not travel 50,000 ft/sec the speed of sound is 1,088 ft/sec and the paintball does not even approach the speed of sound.

It does however excellerate at a rate of 50,000 ft/sec/sec. Acceleration is the rate at which velosity changes. This means for every second that passes the balls velosity would change by 50,000 ft per sec. So in 0.006 seconds (the amount of time it is in the barrel) it changes from 0 to 300 fps. The math stands as
50,0000 ft/sec/sec X 0.006sec = 300 ft/sec
Please note the units used.
Please do not take this the wrong way. I am only trying to explain and if it sounds condicending I am sorry. Physics is one of my favorite things.
Hitmanng

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"I would rather hit once than miss 140 times."
• 07-21-2001, 01:30 AM
M-a-s-sDriver
I'll buy that, math-wise. But that would require that the ball go 300 feet in .006 seconds. Rather, in that amount of time it really only goes about 10 or 12 inches, at which point it has reached it's terminal velocity. Now if you carry out the math, and assume it goes 12 inches, or 1 foot in .006 seconds, 300x.006 is 1.8 seconds. Now that still does not equal 300 fps, obviously, but we are getting close. So far I am off the actual fps number by 80%. The other method is off by about 10,000 %. Even if you use the arguement of RATE of acceleration, that would mean that that paintball would have to reach terminal velocity in roughly 1/180,000 inch, then maintain that velocity through the barrel. The simplest way to visualize this , again, is with a bow and arrow, since the terminal velocity of an arrow and a paintball are almost identical. A typical arrow is approximatly 28 inches long, which makes it about twice as long as a freak barrel, which I have. That means, according to the 50,ooo fps principle, that somewhere along it's path on the bow, it hits a rate of 25,000 fps, which is impossible. Part of the problem here is the expression of 'rate'.
Naturelly, if you CONTINUE to accelerate an object, at any rate, it will achieve the desired terminal velocity. But we have only a small length to propel the ball, and it's terminal velocity is the highest speed it reaches.
Now remember guys: You are thinking I am a completely brilliant person to have these great thoughts, but I have consumed 4 Sierra-Neveda Pale ales, So my thinking is on an entirely different level from yours. (you have to determine which level though).
Again, with the utmost respect to those here, Brent Jackson, PFB.
• 07-21-2001, 02:28 AM
hitmanng
Quote:

<font face="Verdana, Helvetica, sans-serif" size="2">Originally posted by M-a-s-sDriver:
But that would require that the ball go 300 feet in .006 seconds. </font>
No actually it says 300ft/sec so it would take 1 sec to go 300 ft.
Say the barrel is 12 in or 1ft long. To traverse it in 0.006sec the average speed of the ball is
1 ft / 0.006 sec = 166.7 ft/sec.
(Actually the barrel must have been about 10.8 in long so the average was 150 ft/sec)

Quote:

<font face="Verdana, Helvetica, sans-serif" size="2">Rather, in that amount of time it really only goes about 10 or 12 inches, at which point it has reached it's terminal velocity. Now if you carry out the math, and assume it goes 12 inches, or 1 foot in .006 seconds, 300x.006 is 1.8 seconds. </font>
Look at the units here. 300ft/sec x 0.006 sec = 1.8 ft. This is true if the ball were moving at 300 ft/sec the entire time it was in the barrel it would have traveled 1.8 ft but it was accellerating so only reached 300 ft/sec as it left the barrel.

Quote:

<font face="Verdana, Helvetica, sans-serif" size="2">Now remember guys: You are thinking I am a completely brilliant person to have these great thoughts, but I have consumed 4 Sierra-Neveda Pale ales, So my thinking is on an entirely different level from yours. (you have to determine which level though).
Again, with the utmost respect to those here, Brent Jackson, PFB.
</font>
I do agree you are on a different level at this point LOL.

Use the units in the equations it helps. The ball never goes 50,000 fps it could not. It never passes 300 fps. Acceleration, Velosity and distance are very different and the numbers do make sense.

The accelleration in the barrel is 50,000 ft/sec/sec.
The average speed is 150 fps with the lowest speed being 0fps and the highset speed being 300 fps.
The distance is 10.8 inches and the time is takes to travers it is 0.006 seconds.

Hope this helps,
Hitmanng

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

[This message has been edited by hitmanng (edited 07-21-2001).]
• 07-21-2001, 08:27 AM
Motomaz
I never knew that I could learn so much from paintball on a website. This is so cool about the barrles. I found that the stock barrle isn't really that bad but it may break paint more then a aftermarket barrle will. I have a 12 inch boomer and it seems that I never break paint. If I do break paint it's on people http://www.automags.org/ubb/smile.gif

Andrew
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