wondering the same thing on barrel lengthOriginally Posted by UThomas
waiting for MY pump kit...
wondering the same thing on barrel length
Team Dead by Dawn
I am wondering if there is an optimized chamber design that will insure repeatable set ups
IMHO part of the inherent "inaccuracy" of the 68 cal paintball ballistics is the non uniform, lop sided paint and its random, high speed chambering.
Aligning the seams is prolly a waste of effort with gel rounds, but i gather these perfect circle engineered rounds are a Polystyrene shell. Hence the temp & humidity tolerance.
These rounds might benefit from a precision controlled feed.
U R techno-literate!
These were released to where?
I would buy some right off just to tinker with.
Registered User
Did you read the analysis? High Re is turbulent, but when dealing with a sphere that turbulence is a bonus. At higher Re the Cd is lower, it was proven.
As far as spin goes, the fins will exert a force on the surrounding air, causing resistance, and more drag. Spin will stabilize the ball you are right.
Who is to say though, that every paintball doesn't have some form of spin on it when it comes out of the barrel?
Useful posts: 7
TK and the high speed camera testing done to measure for it with publically posted results
"Unless someone like you cares a whole awful lot, nothing is going to get better. Its not" - Dr Suess
Registered User
Did they spin? Do you have enough length of footage to know if they spun?
Useful posts: 7
They did not spin, it was pretty good, controlled testing.
Registered User
https://automags.org/forums/showthrea...&page=11&pp=30Manike made a "bullet" shaped (exact same as the FN303 round) "paintball" that weighed the same as a normal paintball. These have groves that spin the round when it is fired. It flew worse than a paintball. They just don't have enough mass for their frontal area.
Did anybody bother doing a Cg exam on these paintballs as well? When you talk aerodynamics, the Cl and Cg are very.. VERY important.
Useful posts: 7
https://automags.org/resource/tech/to...spinning.shtml
That discusses spinning, or attempting to induce controlled spin, a regular paintball
U R techno-literate!
If you've ever been on the far end of a working tippmann flatline barrel, the difference between a good backspin (which reduces turbulence by keeping the boundary layer attached longer and creates lift) and a knuckle ball is pretty apparent. A flatline barrel with Perfect Circle round paint would be an interesting test since its effects would be reduced without any seams, but would be more consistent.
From high speed photographs, you can see that spinning projectiles, even smooth ones, create different axial wakes compared non-rotating projectiles. The wake is usually elongated and affects the overall ballistic coefficient. Gyroscopic forces do not necessarily create absolute stability, as evidenced by the varying rate of twist in the same rifles shooting different weights of bullets. Wake stability has to be balanced against rotational inertia, center of pressure and center of mass (and sectional density).
Since a paint ball travels at varying speeds starting at 280 fps and decelerates, the reynolds numbers will be continuously falling and the drag coefficients will be changing. There is not a single coefficient, but a set of coefficients through the path.
I would much rather have some to play with.
Registered User
If you've ever been on the far end of a working tippmann flatline barrel, the difference between a good backspin (which reduces turbulence by keeping the boundary layer attached longer and creates lift) and a knuckle ball is pretty apparent. A flatline barrel with Perfect Circle round paint would be an interesting test since its effects would be reduced without any seams, but would be more consistent.
From high speed photographs, you can see that spinning projectiles, even smooth ones, create different axial wakes compared non-rotating projectiles. The wake is usually elongated and affects the overall ballistic coefficient. Gyroscopic forces do not necessarily create absolute stability, as evidenced by the varying rate of twist in the same rifles shooting different weights of bullets. Wake stability has to be balanced against rotational inertia, center of pressure and center of mass (and sectional density).
Since a paint ball travels at varying speeds starting at 280 fps and decelerates, the reynolds numbers will be continuously falling and the drag coefficients will be changing. There is not a single coefficient, but a set of coefficients through the path.
I would much rather have some to play with.
How far do you think the reynolds number will drop though? my guess is not far at all, and it would fall for both projectiles to boot. After 100 feet, how many fps have dropped? Im too lazy to try and find out, is there a test that has been done?
As to the bolded section, you are talking about a spherical section filled with a fluid, that will be pretty difficult, and require pretty tight machine tolerances.
The more I think about it, the more I think these will be less accurate than a regular paintball. They would have to be very well balanced around that central axis to not spin out like a ceiling fan missing 1 blade.
I would really like to see some tests!
Registered User
First "test" I have seen.
edit...link removed
The only problem is that you can't see the paint itself due to the video quality.
Last edited by AO Moderation Team; 02-11-2009 at 11:46 PM.
The man from AGD
Guys,
First off a clarification, you can barrel load these projectiles by pushing them backwards down the barrel. You put them in with the round part FORWARD and the fins toward the bolt like you would expect. I was informed that I said "load them backwards" which some people took as positioning the projectile round end toward bolt.
These projectiles are a direct result of the 10 years of experience we have with the FN303 rounds. You remember, the only paintball projectile used by the government and all that? We reduced the weight to 3 grams and moved it all to the front for good center of gravity. The back of the ball actually has a slight taper where the fins are so the fins are not actually in the main airstream but rely on the airflow to "stick" to the sides of the ball like an airplane wing.
The fins are more aggressive than the FN rounds and since its lighter we think these spin up FASTER and this gives stability to the ball. This created a level of accuracy that even we were surprised with.
The shape gives it better aerodynamic flow so this round holds its velocity down range a LOT longer than a regular paintball. In my discussion with Gary today he told me that when a regular paintball slows down to 125, the Sniper Round is still doing 235 at the same distance. We believe people with think your shooting hot when you touch them at distance.
We have sent out projectiles to people for testing and there is going to be a video from Tiberius coming out tomorrow. These projectiles were half hand made to make the show so there is no streamlined production yet, but that is happening soon.
Stand by and everyone will get a "shot" at these
AGD
AO Mod Team
Please dont post links to vids with swearing. The link was removed. Nothing like dropping the F bomb. Could someone tell this Mike guy at TechPB that it would be alot more professional if he could make a vid without all the swearing it makes him sound less cool.
Last edited by AO Moderation Team; 02-12-2009 at 12:00 AM.
-The AO Moderation Team
"Everything in Moderation"
Registered User
Opps, I didn't think about the swearing when I made the link, sorry.
Anyways, I think this is a cool idea. If they work well, someone should make an x-mag breach for them so at least one AGD marker can use them effectively
Registered User
Can you please pm me the video?
Registered User
It was made by TechPB on youtube if anyone wants to look it up.
Registered User
Thanks pgen, the unfortunate thing about it is that they did not shoot regular rounds right before or after, to see if they were "more" accurate.
Cheater Tac one
I wonder what kind of drop or rise we will see between these and reg paint over the chrono. Say if you muzzle load one during a game for that "sniper" shot.
I could tell you but then.
That would depend on the WEIGHT difference of the two projectiles. If they both weighed the same the velocity would stay the same.
it only takes one.
And i beleive Tom said they do weigh roughly the same.
Im really stocked to see these. I want to try them.
Cheater Tac one
Not necissarily. If the bore size is slightly diffirent for example there might be some air that passes by, or through the fins, causing it to be slightly lower FPS. or the fit might be better. even if the weight is the same the "push" behind the projectile might not be the same. Put a bb in a small straw and blow it out, it goes pretty far. now put a bb in a larger straw. wont go half as far. This is where i see issues with muzzle loading one in the middle of a game. what if the paint you were using was .686 and the projectile is .691. you use the .691 barrel so that you can fit one of these. then chrono using normal paint. the better fitting round should chrono quite a bit higher. And how are fields going to control this?
Last edited by jade_monkey07; 02-12-2009 at 01:40 AM.
Everything AGD
No different than if you have two different sized balls in your pod or loader. The effect is some, but not all that much.
U R techno-literate!
The only question I have left is; how does the marker bolt work against the back of the round? It was not a question on the fn303 round, but the hollow skirt is causing me some difficulty on my semi-auto sniper marker design.Stand by and everyone will get a "shot" at these
AGD
I can see the guys with the night scopes getting some of this action.
Last edited by Spider-TW; 02-12-2009 at 09:47 AM.
Everything AGD
As long as the walls where the fins are are thick enough that the bolt wouldn't get stuck in the back of the round, it shouldn't be a problem firing. I do wonder if it makes it fly any different than a solid back. I figured they would have put a back on it, but left it hollow (basically an FN303 round with an empty payload and paint instead of bismuth).
Registered User
Amen Tom.
While I am cautious about any new technology, Tom is right about the state of the game. It's up to us to get away from the "shooting ropes" mentality, which, let's face it, which is really lame, lacks skill, and has been killing the game, especially for newbies and walk-ons. When I started playing paintball back in '92, my 2nd marker (2 months after buying an Indian Creek that I didn't like) was an Automag, and I didn't have to lay out paint with it, because it was, and still is, one of the most accurate and consistent markers out there. Hell, half the guys we played with (even me on occasion) played pump and semis mixed, and the game was all about stalking, marksmanship, strategy, and skill. Now, even woodsball is about "laying ropes." Let's get back to the days of strategy and skill, and if this round brings it back, then I welcome it with open arms. Make my next marker a Tiberius! (This from a proud owner of 4 classic automags, still owning my original Automag from 1992.)
BIGEVILONLINE
i just watched the techpb vid, pretty impressive, they used a sniper set up with .689 barrel, that was chronod at 290 before they used the tib rounds, the rounds were flying pretty darn straight and they hit theyre target everytime i believe, vids not the best quality, but you get the piont.
JJ's Master
Tom-
What RPM do these rounds spin up to? If I remember correctly from a tech class the spin would need to be around 6000rpm for any accuracy improvement.
In a thread from Jan 2002 you're quoted "We spent the time and money years ago. If there was anything to be had for better accuracy it would be worth a million dollars to AGD. We would have gone in that direction." from this post: https://www.automags.org/forums/showt...threadid=20862
Isn't the FN303 projectile your design?
Everything AGD
Brian,
You are thinking about a normal paintball vs the finned FN303 style round. If they could get traditional paintballs to be any more accurate by spinning them, then yes, it would have been the multi-Million dollar gadget.
FKC Founding Member
where can I buy these to try out?
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