Help testing spin

[auslandt]

I tried to post to deep blue, but I'm not authorized. So I guess I will post my question here.

I am looking to simulate barrell porting and its effects on ball spin. However, doing this with a true marker, and real hardware is expensive and hard to collect data. Those dang paintballs move way too fast.

Does anyone think using pingpong balls, PVC pipe, and a shop vac to simulate a
paintball marker and barrel would be valid for prelim data? I would much rather
pay $2 to port a PVC pipe than tens or hundreds for a real barrell.

[THOR_MAG]

I don't think you can get any usefull results simulating a paintball barrel with pvc pipe and a ping pong ball. A ping pong behaves different than a paintball because it has a different weight and it's not filled with a liquid. besides that if you wanna simulate something like that accurately you have to make sure that you get the same kind of air flow (laminar or turbulent) means the same reynolds number for the flow in your pvc pipe than you have in a paintball barrel.
But hey you can still give it a shot to check if the porting influences spin at all. I'm just not sure if you than can transfer your result to paintball.
Let me know what the results are if you've tried it!!

[Army]

Just to save you a lot of trouble, time and expense; porting has no affect on spin. It does not create, impart or take away spin. Remember, porting occurs AFTER the ball has passed the port, simply decreasing the pressure in the barrel. The ball no longer has pressure pushing it immediatly after any porting, so the air cannot effect any more force.

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EIB

[fenris69]

yknow...i was drunk the other day...no when was that...oh well. in any case i had an odd idea...what if the blast of air struck the paintball at an angle...ie there was a way to let the gas flow diagonally across the balls surface via some sort of port beneath the ball coupled with a large bore barrel... i know, odd but a thought nonetheless. oh yeah, now i recall i was playing with a J&J whisper the one with the two cuts right after the thread for an oring, but i dont use one, wonderfully quiet for an 8in barrel albeit a little inefficient.

[PyRo]

I think this has been tried, backspin bolts... The bolt has an air port only on the top or bottom, to put backspin on the ball. The only problem with this is when you change your velocity the amount of backspin will change. It would also probably be inconsistant.
You can forget about doing it on a mag. If you set it up so the bolt didn't spin it would wear out way to fast.

[Miscue]

If you could make a paintball move like a ping-pong ball, you could shoot forward and hit yourself in the back. Well, not quite, but the ball does behave entirely differently.

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"Don't mill your tank." - Miscue

Miscue's Profile

[auslandt]

Thanks Army for the insight.

I was thinking that porting on one side would "draw" the ball to a side. If a
larger bore barrel was used it would ride one one side of the barrel. Then the
ball would end up getting some rolling action over the sliding action and
thus impart spin... Not due to the air but due to the rolling friction. I didn't want to know how it worked with paintballs, I was wondering if that was feasable dynamics... Electrical Engineers have NO concept of dynamics.

But with your comment I think I have come up with a better idea.

What if there was a SMALL grove at the bottom of the barrel. This would
allow the high pressure gas a SMALL escape route around the bottom of the
ball. The higher velocity air might impart a backspin.

I know ping pong is not equivalent to paint ball, but it should help me
understand the dynamics of the air.

[Hasty8]

What you are describing is called the Magnus Effect it is exactly that premis that the Tippmann Flatline barrel utilizes. The X-body also tried to accomplish this for the Mag family of markers. A small nubbin would force the ball to backspin as it came out of the barrel. It never worked all that well according to the reoprts I read.

If you relly want backspin you can't go much better then the Flatline. There is a Flatline Autococker. When I get ther time I'll try to reverse engineer my flatline to my emag.

[THOR_MAG]

Beam: Yes I'm Thorsten who plays at powerstation!!
Sorry I can't make it there that week I've to go to Ames and take care of some things at ISU. CU some other time hopefully
Thor

[beam]

Thor_Mag!!!! are you the thor that plays at Powerstation...if so...i'm that other mag user...the one that had the z-grip a few weeks back! i will be back there on sun. the 2nd with my warp and intelliframe woohoo