Paintball Physics

[THE JEW (RaVeN)]

Good refresher:

http://lennon.csufresno.edu/~nas31/nsa/pballIntro1.html

[THE JEW (RaVeN)]

Science experiment:

http://www.sciencebuddies.org/science-f ... p054.shtml

[THE JEW (RaVeN)]

Barrel break test with under/over-bore:

https://spreadsheets.google.com/pub?key ... 44CEWQxNDA

[THE JEW (RaVeN)]

Bazooka theory:

http://www.techpb.com/forum/index.php?showtopic=150496

[THE JEW (RaVeN)]

Tech data on certain guns:

http://www.automags.org/forums/showthread.php?t=34429

[THE JEW (RaVeN)]

Summary of current barrel knowledge:

http://www.youtube.com/watch?v=197yZ859 ... re=related


Punkworks of TechPB is an excellent resource as are the forums of Doc (plus, he has a cartoon strip and 'toons are always good).

[THE JEW (RaVeN)]

Trajectory calculator:

http://home.comcast.net/~dyrgcmn/pball/trajectory.html

[THE JEW (RaVeN)]

External Ballistics Primer:

http://www.techpb.com/forum/index.php?s ... try1297285

[THE JEW (RaVeN)]

What a 3mph crosswind does to your flight path.

[THE JEW (RaVeN)]

Underbore / Matching / Overbore:

http://www.techpb.com/forum/index.php?s ... try2823702

Underbore - increased efficiency, good consistency (don't go smaller than .007" under the paint though; .004-.005" is your target for underboring)
Paint to barrel match - less efficiency than underbore, and less consistency
Overbore - worst efficiency of the bunch (only about 7% worse though), and will have good consistency, matching that of the underbore.

accuracy seems unaffected until you get to extreme under and overbores. extreme underbores (.007+) add TONS of spin to the ball, decreasing accuracy.

Excellent, thanks. The data from that video meshes nicely with the data from this test, showing ~.03 underbore being the best.

http://www.techpb.com/forum/index.php?s ... try3071440

[THE JEW (RaVeN)]

Flow pattern of paintballs:
http://upload.wikimedia.org/wikipedia/c ... mation.gif

Kármán vortex street, the description of how paintballs move through the air:
http://en.wikipedia.org/wiki/K%C3%A1rm% ... tex_street

Bluff bodies definition:
http://www.princeton.edu/~asmits/Bicycle_web/blunt.html

[THE JEW (RaVeN)]

Dual chrono test of 100'

https://spreadsheets.google.com/spreads ... MTEE&gid=1

[THE JEW (RaVeN)]

Efficiency and consistency as relating to control-bore length and bore:
https://spreadsheets.google.com/pub?key ... E5ioZ_zbNA

iFit control bore kit:
https://spreadsheets.google.com/pub?key ... utput=html

[THE JEW (RaVeN)]

Maximizing your fps legally:

http://www.mcarterbrown.com/forums/palm ... ost2345649

[THE JEW (RaVeN)]

http://www.mcarterbrown.com/forums/dead ... ost2346189

Originally Posted by Kilroy
Interestingly consistency didn't relate to accuracy in any of their tests.

I'm anxiously waiting for them to do a test that attempts to correlate spin & accuracy to back up their theory.

Logically consistency HAS to have something to do with accuracy. What we've hypothesized is that the small variations in trajectory due to fluctuation in velocity is masked completely by the problems inherent in the system. In other words - paint is such a crappy projectile that it makes the ball do random things in a massively bigger range than say +/- 15 fps.

As to the spin - this is a good question. We have shot the Apex - and at no settings did we change the trajectory of the paintball to make it more or less accurate. As CockerPunk likes to say - a lack of a result is just as interesting as a result.

Every set of high speed footage we've taken of balls exiting the barrel have shown random direction and rates of spin - up to about 2400 rpm. It seems that spin either doesn't effect accuracy or again, is masked by other problems with the ball. I'm not certain.