PPS Blazer Barrel = 'Elliptical Honing' ...does it work?

[Jack & Coke]

Interesting read regarding the elliptical honing of Palmer Pursuit Shop's barrels for their gun, the BLAZER:

From: http://www.palmer-pursuit.com/techpages/Palmerinfo2.htm




Glenn Palmer says that it is most important (for accuracy) to match the barrel to the output of the valve.

Huh? Read on...

Really, this is another way of saying you need a good paint to bore fit. Not too tight, and not too loose. A paintball will deflect radially (get bigger) when pressure is applied by compressed gas. The pressure output of the valve rises, peaks and then falls. It is not a digital on/off device. If the valve output pressure rises, peaks and falls, then the paintball diameter will rise, peak and fall. This makes it impossible to get a good paint to bore fit with a straight-profile (constant I.D.) barrel.

A good example of this is when you get ball breaks halfway down the barrel with a high-pressure gun and a straight profile barrel. Enter the elliptical profile barrel. The inside diameter of an elliptical-profile barrel is tight at the breech, loose down the middle, and tight at the muzzle. Sound familiar?

The elliptical-profile barrel allows a good fit of the paintball to the barrel all the way down its length. The vented barrels are tight all the way through the venting, so the bulge is closer to the breech of the barrel. I believe this only applies to high/medium pressure guns like the Typhoon. It would seem that the benefit of elliptical honing diminishes with low-pressure guns that don't deform the paintball as much. With low-pressure guns, a properly fitted straight-profile barrel is all that is required to achieve the same quality of paint to bore fit.

The goal of the hone/shoot/rehone process was to get the balls to come out with no spin. It follows that a good paint to bore fit will produce less spin than a bad one. Spin detracts from accuracy at long ranges, as the paintball slows down, the spin becomes the dominant force. This produces the "hook" shots you get out of lesser guns. A paintball with no spin acts like a "knuckleball" in baseball, causes it to wiggle back and forth, up and down along its path. This wiggling will keep the ball close to the initial path, at all ranges. A spinning ball will be closer to the path at close ranges and further from the path at long ranges.




Very interesting theories regarding the physical dynamics of paintball ballistics... :)

What do the brain trusts of AO think?

[cockermongol]

makes since if it's true that a paintball will really expand at mid-barrel. seems like that type of thing would be impossible to measure...

[Jack & Coke]

well, for what it's worth...

Look at these high speed photos AGD took of paintballs as they are fired through a clear barrel at regular velocity:

http://www.automags.org/forums/attachment.php?s=&postid=526782

http://www.automags.org/~TomAGD/1%20spindata/smoke1_lg.jpg

http://www.automags.org/~TomAGD/1%20spindata/smoke2_lg.jpg

http://www.automags.org/~TomAGD/1%20spindata/smoke3_lg.jpg

read more about it here: http://www.automags.org/forums/showthread.php?s=&threadid=34429

The ball does not appear to ever be 'deformed' during flight.

[Doc Nickel]

We're still arguing distortion? Sheesh. Okay, let's try this...

First off, how much does the ball distort? To answer this, I whipped up a quickie little aluminum doodad. It has a flat-bottomed .750" hole and a cross-drilled hole for a dial indicator. I used a .0005"-graduated indicator, held in by a firm press-fit. The paintball goes in the big hole and the spring-loaded indicator shaft holds it against one side.

http://www.docsmachine.com/tech/distort01.jpg

I zeroed the indicator dial and put the works in my handy-dandy arbor press. The paintball, in this case, when resting against the bottom of the hole, stuck up by almost exactly 0.075".

http://www.docsmachine.com/tech/distort02.jpg

All that remained was to squash the ball in the press that seventy-five thousandths.

http://www.docsmachine.com/tech/distort03.jpg

Total gain in "bore" diameter of the ball: just over 0.0035", or three and a half thousandths of an inch.

Is this a "realistic" test? No: Firing the ball for real applies pressure over the entire half of the ball, the entire hemisphere facing the bolt. This test focused the pressure on two flat surfaces, exaggerating the distortion. In a paintball gun, the burst of air would spread out to conform to the entire half of the paintball, reducing the forces to a minimum.

Also, I was forcing the ball into a hard surface. In the paintball gun, the only resistance facing the ball is the ball's own inertia and the very minor drag- if any- from the bore itself. In other words, it has only an open barrel to hold it back.

So unless I'm missing some interesting factor, it looks to me like, if we give the ball the absolute worst possible conditions in an effort to induce distortion, we get only .003" to .004" change.

And those conditions are not replicated when actually firing a ball- conditions in which case are actually optimized to reduce distortion.

While I won't declare the matter "closed" just yet, I believe we can very accurately say that the paintball does not distort to any appreciable degree when fired, nor in flight, and by no means enough to have the barrel attempt to "follow" that pattern of distortion.

Doc.

[Doc Nickel]

Oh, and one other thing:

Palmer's "eliptical hone" is "football" shaped- the bore is very slightly wider in the middle of the barrel, and thinner at both the breech and muzzle ends.

However, even if we assume that the air burst is enough to distort the paintball, where will the point of greatest distortion come? According to this chart:

http://www.automags.org/forums/attachment.php?s=&postid=299290

The peak pressure comes pretty much before the ball starts to move, and drops off sharply thereafter as the space between the bolt and ball increases.

Therefore, if Palmer's above-quoted concept of why their eliptical hone works, the largest portion of the bore should actually come at the breech, and it should taper down to the smallest about 2/3rds of the way towards the muzzle. It would need to be cone shaped, not football shaped.

Palmer does make some nice barrels, sure, but lets not call it magic or make up some SP-like terminology to explain it, eh? :D

Doc.

[Jonesie]

Nice posts guys! VERY informative. J&C can really come up with some thread topics, no?

And Doc blinded me with science! :D

[cledford]

Glen and Tom got into this in the Deep Blue flight physics thread.

Glen SWEARS by the elliptical honing yet will freely admit that his testing consists of nothing more then a gauge, a chrono and his eyes. If he can see it, he believes it - but I don't find that good enough for a guy of his stature. I'm not bashing Glen Palmer - I admire him as much as Tom, only for different reasons. That having been said, Glen (by his own public admission) doesn't put anywhere near the amount of research into his stuff that I thought that he would have. I was pretty surprised.

I'd still like to have one of his products as they're handcrafted pieces of paintball "metal-art."

-Calvin

[thei3ug]

the way he tests his barrels is enough to figure out whether they work or not... elliptical honing or no. keep in mind he HAS to rehone them... they're soldered on to his guns!

as for saying he's gone, when did he do this???

[cledford]

He said this a month ago - he was possibly only refering to Deep Blue:

Exactly why you haven't seen me participating in Deep Blue lately

from: http://www.pbnation.com/showthread.php?s=&threadid=316927&perpage=21&pagenumber=5

I'm changing my post above, I mis-stated his position.

-Calvin

[thei3ug]

oh yah. i forgot about that. doh.

oh well, i'll just keep sticking around POG.

[Jack & Coke]

Great post Doc! :)

cledford nice thread too (pbn)

[ForgedSpeed]

Am I missing something here.. because it seems to me one could just hook up a normal barrel and eliptical barrel to a gun, test the accuracy and that would be the end of it.

[Muzikman]

Not quite that easy...

[Ityl]

First of all, I wouldn't rule out something because high school physics says something happens a certain way. When I took physics in high school (2000-2001) we were neglecting friction.

Secondly, a paintball traveling at 300 fps with no spin can only travel so far. The Flatline barrel for the Tippman 98 shows that spin on a paintball can affect range, there is NO way you can argue against that.

Thirdly, this barrel design could just make a ball exit the barrel in a more consistent fashion, therefore increasing accuracy (well technically precision).

This isn't directed to anyone specifically. Just remember there is more to the world than High School physics.

[Butterfingers]

The burnouli effect as in the tippman flatline does NOT increase range and Ill tell you why...

It is an aerodynamic effect that increases loft thus it brings the range of the paintball into the feild of view of the shooter.

You can easily get as much range with a normal marker by tilting the barrel up plus it will break easier at the end of its travel.

If you tilt a flatline barrel up there will come a point that the loft will just send the ball straight up.

High school physics are 100 percent correct PROVIDING it is used in the PROPER context.

[Butterfingers]

Originally posted by Ityl

Thirdly, this barrel design could just make a ball exit the barrel in a more consistent fashion, therefore increasing accuracy (well technically precision).




I definately agree...

This is a question where it is not really applicable to quote high school physics eventhough it sounds cool.

The truth is we dont know. Palmers explaination is based on an assumption of paintball deformation which the photographs and docs test show is highly unlikely.

There are multitubes of explainations that could be attributed to the end result. Palmer sees the end result which is great... It works...

What if the eliptical bore effectively arrests spin in inconsistent paintballs....

What if the eliptical bore does somthing to effect consistency?

Any one of those could be a suitable explaination...

Our purpose here is to try to find out WHY it works.

The end DOES NOT always justify the means... just as the end result does not always justify the explaination.

Palmers barrels may work but the evidence shown proves to a good extent that his explaination is unlikely.

[cledford]

Originally posted by Butterfingers

Our purpose here is to try to find out WHY it works.

The end DOES NOT always justify the means... just as the end result does not always justify the explaination.

Palmers barrels may work but the evidence shown proves to a good extent that his explaination is unlikely.

I agree.

-Calvin

[GatoLoco]

correct me if i am mistaken, but mr. Kaye's tests were conducted using their brand of paintballs. I would be interested in finding out the results of using many different brands of paintballs.....

[Butterfingers]

The tests were done in a specially made precision bored GLASS barrel so that they could see inside.

AGD dosent have a special brand of paintball... except the ones used for Law enforcement. I beleive the ones used in the test were off the shelf gelatain.

[GatoLoco]

not to flame but........ i believe it was a plastic barrel using agd's special plastic balls

[FallNAngel]

Originally posted by Butterfingers
The burnouli effect as in the tippman flatline does NOT increase range and Ill tell you why...

Alright, here's what you do. Take a non-flatlined marker and shoot it level 5 feet off the ground at say... 270fps.
Now, take a flatline barrel and shoot it level 5 feet off the ground at the same speed. The flatlined marker *WILL* shoot farther.

Now if you want to argue that it's useless because you could just "lob" balls to get the same range, that's fine. But the fact of the matter is, flatline barrels *DO* make you shoot farther.

[Ripper machinist]

One thing I would like changed on docs test, would be to have some kind of cup holding the ball that pushes against the indicator. I am just curious if as the ball expands against the point of the indicator, does it bulge around the indicators point?

Jim

[Butterfingers]

Originally posted by FallNAngel


Alright, here's what you do. Take a non-flatlined marker and shoot it level 5 feet off the ground at say... 270fps.
Now, take a flatline barrel and shoot it level 5 feet off the ground at the same speed. The flatlined marker *WILL* shoot farther.

Now if you want to argue that it's useless because you could just "lob" balls to get the same range, that's fine. But the fact of the matter is, flatline barrels *DO* make you shoot farther.


Increased range and flatter trajectories are two diffrent matters. In this case...

There is an absoulte limit to how much kinetic energy a ball can cary before running out of steam.

They just come at diffrent angles.

[Butterfingers]

Originally posted by GatoLoco
not to flame but........ i believe it was a plastic barrel using agd's special plastic balls

I thought otherwise But Im not 100 percent sure...

[GatoLoco]

we should wait for tom to post in that case

[cledford]

Originally posted by GatoLoco
not to flame but........ i believe it was a plastic barrel using agd's special plastic balls

Tom produces a line of paintballs called "Perfect Circle" and they are perfectly round (unlike ALL gelatin paintballs) and made of plastic.

The only difference between them and a normal paintball is that they have less flaws (dimples, out of round, varying sizes in same lot) therefore should be more accurate them ANYTHING else there is. The only thing that could be gained by using normal paintballs (assuming he *didn't*) would be *worse* results then he posted.

-Calvin

[GatoLoco]

Originally posted by cledford


Tom produces a line of paintballs called "Perfect Circle" and they are perfectly round (unlike ALL gelatin paintballs) and made of plastic.

The only difference between them and a normal paintball is that they have less flaws (dimples, out of round, varying sizes in same lot) therefore should be more accurate them ANYTHING else there is. The only thing that could be gained by using normal paintballs (assuming he *didn't*) would be *worse* results then he posted.

-Calvin

this is all well and good, but if it is made of a different material, than it may perform differently. There is no control in this experiment, the data just shows how PLASTIC paintballs perform in flight.

[Ityl]

Originally posted by Butterfingers


Our purpose here is to try to find out WHY it works.

The end DOES NOT always justify the means... just as the end result does not always justify the explaination.

Palmers barrels may work but the evidence shown proves to a good extent that his explaination is unlikely.

My post wasn't directed to those who were trying to figure out why it works, but the ones saying that it can't work.

Also, regarding the flatline, my point was not that tilting a normal gun can give it the same range as the flatline, but that when the barrel is level, spin does affect range.

[trains are bad]

Shotguns (the firearms) use overbored barrels and choke in thier barrels. What this elliptical honing reminds me of is shotgun choke. It might work, even if it's not because of why Palmers says it does. Sounds like a good idea actually.

[BlackVCG]

Sorry, but the Bernoulli Effect really doesn't apply to the flight of paintballs since you're dealing with compressible flow. You can't account for the density changes that result with compressed air with bernoulli's because it applies to incompressible flow.

I suppose it's okay to use it as a base model for what's going on, but it gets a lot more complex than what Bernoulli's equation shows.

[Jack & Coke]

more interesting ideas and theories from Glenn Palmer...

from:http://www.palmer-pursuit.com/techpages/barrels.htm




PPS Barrels
[list=1]
IMHO, brass provides the least friction against gelatin and the best opoptunity to get it shaped and finished properly.

There seems to be a general "GADGETUDE" that wants to try to match a barrel to the paint being used. (of course this is promoted by those that want to sell barrels) It is far more important to match the barrel to the guns valveing and the way the expanding gas is used/released. The only other factor that I feel needs to be addressed in barrel selection is that of length. The variable that effects the decision of what length to use is temperature averages. As temperature raises, the gas is under higher pressure and is able to expand and accelerate faster, making a short barrel useable, but anything under approximately eight inches becomes counter productive in all but extremely warm conditions. On the other hand, colder weather slows down the expansion process and requires a little longer tube to allow things to get up to speed without wasting much of what is released by the valve. A barrel that is too long will also yeild unfavorable results due to the extra gas needed to keep the ball moving past the point where desired velocity is reached. Too much gas generates a muzzle blast that effects the ball after it has left the barrel. Who knows what direction a ball will take when the gas blows past it outside of the guidence of the barrel. In most cases, 12" should be considered as the maximum effective length for a paintball barrel. The presure options from a regulated high-pressure system will also affect the choices for "optimum" barrel length in much the same manner.
the texture and shape of the bore are both important to consistancy and effectiveness. (FYI: Colin Thompson and I generated some huge phone bills with discussions over valving and launch tube shapes, while trying to come up with ways to achieve the right ballance, many years ago.)

The way that we set up barrels here depends on the gun and its use. However, the basic concept is based on a shape that is slightly eliptical. A little tighter at the breech and muzzle than in the center section of the tube. The specific dimensioning will vary with the type and setup of the gun. We have had good results with shapeing to meet the basic need of guns by brand but will usually achieve better results when we have THE specific gun to work with.

[/list=1]

[hitech]

Glenn’s elliptical barrels do seem to work well when it comes to avoiding barrel breaks. They are probably fairly efficient. However, they are NOT any more accurate than any other barrel. Like I said in the recent hammerhead thread, I could explain, but everyone has already made up their minds where accuracy is concerned.

Tom also tested his Prefect Circle paintballs. They were not any more accurate than normal paintballs; for the same reason all barrels are the same, accuracy wise.