How many bps is too many bps..Technical Question

[alexrusek]

Ok here's the question for everyone. If I'm firing a pb marker at 300 fps. With a ultimate hopper that can keep up, a fully automatic programable trigger, a gun clamped down, a valve/gun assemply that never has shotdown, and a hpa tank sooo awesome i never get any shootdown.

How many bps do i need to shoot before the balls will catch up to the balls shot before it, thus bursting the balls in the air.

Or is this impossible because of physics?

[paintballman_13]

it would not break the balls unless u had 2 markers beside each other.

[alexrusek]

i was thinking that if u were to get to a speed that the balls were touching eachother as they were coming out, and u upped the speed a little, the one coming out would slow down enough to be hit by teh ones going faster because they were jsut fired.

Also im talking about a single gun


and this is strictly hypothetical

[SlartyBartFast]

Well, I you consider it takes 5ms for the paintball to accelrate to the end of the barrel, you could for the sake of hypothesis eliminate cycle time from the equation.

That would mean a maximum of 200bps allowing for the complete accelration of the ball from the barrel.

The only way one ball would catch up with aanother on the other hand, would be that the previous ball was misfired.

If all the balls are leaving the barrel at the same speed, they experience the same deceleration forces as soon as they leave it. So in the ideal world at 300 fps with instantaneous load at 200 bps, each ball would be 5ms apart.

[Wat]

Assuming the ball goes to 300fps instantaneously and there is zero barrel length...

Lined up end to end, there are 17.6 68cal paintballs in a foot. Multiply that by 300fps and you get 5,300 balls per second.

Of course, in reality, we cannot accelerate a ball instantaneously. The limiting factor would be how long the paint in the barrel is being accelerated by the gas behind it because as soon as the breech is open to load the next ball there would no longer be any propellant force.

[athomas]

All balls would have the same rate of acceleration. Therefore, no ball will catch up to the previous ball. The only way a ball will hit a previously fired ball would be if it was traveling faster than the previously fired ball.

[homis]

With balls being fired that close, what about a decrease in air resistance for balls travelling behind? Although I'm not familiar with the type of air that a paintball leaves behind it (ie dirty or clean wake), everyone's familiar with a small car being 'pulled' by a semi in front of it.

[Top Secret]

From what I understand, I think he is wondering when a paintball would "draft"(think car racing) behind another to the point that it would catch up and collide.

[homis]

Top Secret,

Exactly what I'm referring to. My question is focused on whether paintballs leave a 'clean' wake (think NASCAR) or 'dirty' wake (F1). You can draft in NASCAR, but you get screwed up if you follow another F1 car too closely because of the 'wake' they leave in the air. If paintballs leave a relatively clean wake (and are spaced close enough together), I could see it becoming a viable phenomena. Since Tom has studied the properties of a paintball as it travels in flight, I'd be quite curious to hear him pipe in.

[madgoat33]

You should build your own vacuum and test this out, because if you were in a vacuum, it is theoretically impossible, so right now with our resources the only place a ball could touch another when fired same velocity out of same gun would be on earth.(even then it would be a phenominom just like somebody else already stated)

[MrWallen]

Also, if you WERE firing that fast the balls would be colliding at the point where they entered the 'chamber'of the marker, most likely resulting in a chop, or misfire.

[homis]

madgoat33,

If I understand correctly, you are referring to the concept of the 'drafting' (or lack thereof) of paintballs being played out in a vacuum. Since a true vacuum provides no resistance to an object in motion, any objects traversing the same trajectory behind a single or (even better) multiple projecticles would not benefit from the previous, and thus all objects in motion (as long as spin, velocity and composition were the same) would have identical flight characteristics. Although there is a definate validity to this concept as an empirical exercise, for all intents and purposes the results are inconsequential - in no likely real world circumstance would this occur. Thus, I am still faced with the question of whether paintballs fired at a high rate (in the real world, with a real world atmosphere) would suffer midair collision due to the drafting of a single ball from air resistance advantages gained from previous previous rounds fired. It is not something to which I neccesarily subscribe, rather a response posed as a plausable explanation for an otherwise unexplainable phenomena.

[Doc Nickel]

Some of the Tinker's Guild regulars poked this idea around a few years ago. The thread was so interesting I archived it Here.

The two points relevant to the original post in this thread:
The ball has to travel at least it's own diameter before the next can be fired, and at 300 ft/sec, that equates to 1,734 balls per second.

And, as already noted above, if you assume the first ball at least leaves the barrel (12" tube) before the next is fired, that equals 200 shots per second.

Also note that, in the first example, remember the paintballs would have to be entering the breech as fast as they're leaving- the hopper itself would have to get the balls up to 300fps.

So why not just shoot 'em with your hopper?

Doc.

[paint magnet]

If they were entering the breech at 300 fps, wouldn't this break them as soon as they entered the chamber?

[SlartyBartFast]

Originally posted by paint magnet
If they were entering the breech at 300 fps, wouldn't this break them as soon as they entered the chamber?

Who cares? The whole question is hypothetical anyways. If you can get a ball out of a hopper and into the breech at 300 fps, to quote doc:

Originally posted by Doc Nickel
So why not just shoot 'em with your hopper?