Smaller Balls are you ready?

[thejere]

@Lohma446

I think you mean the forces are different on the balls, the rules of PHYSICS don't change with caliber.
Here we go though:

Basic physics first (No Drag).
Standard Cartesian Coordinates, horizontal shot
forward travel of a paintball (D) = velocity(V) * time(t)
time(t) = 2 * height fired from (h) / acceleration do to gravity (g)
Solve for distance D = 2*V*h/g
forward travel is a function of velocity, height fired from, gravity, not the size, mass, color, etc of the paintball.

Lets bring in fluids:
Force from drag (Fd) = .5 * Coefficient of drag (Cd) * density of air (pa) * velocity squared (V^2) * frontal area (A)

Frontal area (A) = pi * r^2

deceleration due to drag (d) = Force from drag (Fd) / mass of paintball (m)
mass of paintball (m) = volume of a sphere (4/3 * pi * r^3) * density of paint (pb)

Lets assume most of the mass in a paintball is the paint so this will be the same for either paintball and lets take all things that don't change, everything but the radius of the paintball, and group them as constants. We end up with:

deceleration (d) = constants *r^2 /r^3 = constants / r

Lets compare the deceleration based on the radius of the two different size caliber paintballs.
deceleration of .50 caliber = 4*constants
deceleration of .68 caliber = 3*constants

So it would seem that .5 cal paintball, although having less of a force of drag acting on it, will decelerate quicker due to the reduced mass of the paintball.

Your rebuttal?

[Lohman446]

@Lohma446

I think you mean the forces are different on the balls, the rules of PHYSICS don't change with caliber.
Here we go though:

Basic physics first (No Drag).
Standard Cartesian Coordinates, horizontal shot
forward travel of a paintball (D) = velocity(V) * time(t)
time(t) = 2 * height fired from (h) / acceleration do to gravity (g)
Solve for distance D = 2*V*h/g
forward travel is a function of velocity, height fired from, gravity, not the size, mass, color, etc of the paintball.

Lets bring in fluids:
Force from drag (Fd) = .5 * Coefficient of drag (Cd) * density of air (pa) * velocity squared (V^2) * frontal area (A)

Frontal area (A) = pi * r^2

deceleration due to drag (d) = Force from drag (Fd) / mass of paintball (m)
mass of paintball (m) = volume of a sphere (4/3 * pi * r^3) * density of paint (pb)

Lets assume most of the mass in a paintball is the paint so this will be the same for either paintball and lets take all things that don't change, everything but the radius of the paintball, and group them as constants. We end up with:

deceleration (d) = constants *r^2 /r^3 = constants / r

Lets compare the deceleration based on the radius of the two different size caliber paintballs.
deceleration of .50 caliber = 4*constants
deceleration of .68 caliber = 3*constants

So it would seem that .5 cal paintball, although having less of a force of drag acting on it, will decelerate quicker due to the reduced mass of the paintball.

Your rebuttal?

Frankly, my rebuttal is that I intended to note that the diameter of the ball would effect the physics. Of course, I also assumed that the way they "fixed" the problems with 50 caliber was to keep the same weight as 68 so I left that constant, leaving the decrease in drag being the only variable and calling for further flight.

[Mechanic79]

the further they go the slower they go. like the flat line barrel.

Also, why would further matter; tournament fields are so small already?

.50 sounds like it would have a market in woodsball and for training purposes.

But it will all come down to attorney's, patents, and/or possibly the free market.

[Reiner]

.50 sounds like it would have a market in woodsball and for training purposes.

Oh come on. I run a recreational (woodsball) field. Don't try to pawn them off on me.

[thejere]

[Smoothice]

I'm no physisisisiscist....

Would a .50 cal ball require less air to get up to speed? Thus making a more air efficient marker.

Or does that depend on its weight more then size?

[deathbypaint1213]

I'm no physisisisiscist....

Would a .50 cal ball require less air to get up to speed? Thus making a more air efficient marker.

Or does that depend on its weight more then size?

I believe the 50 cal rounds are being designed with similar weight to a 68 cal (thicker fill). The heavier the object, the more force is needed to start/stop the object.

I think the 50 caliber rounds will affect the sport in both a positive and negative way. It will allow companies to produce more products, and increase competition. On the other hand, the last thing we would want to do is buy gear needed to shoot 50 cal (guns, barrels, etc).

[Frizzle Fry]

Uhhhhh....

PMI made a .55 cal version of their "Black Maxx" a few years back called the "Maxx55". Also, PCS (during the same era) did a version of their "US-5" (an a5 clone) in .55 cal as well called the "US-55". In both cases the paint was very cheap, the markers came with a case, and they spent two years on the market until players "shrugged" the products into oblivion. Nobody wanted the hassle it seemed, and the paint hurt like hell... Especially when it was old, which it inevitably was, because few people carried it. I've seen a couple fields who still have them because they bought a bunch for rentals and the paint dried up.

I've seen these US5 and Maxx55 kits for sale with barrel, hopper, etc for prices like $15 + shipping

The only "small" paint that I've seen with any kind of reputation or following seems to be .43 cal because many pistols dating back to the early 2000s utilize them, as do shell ejecting milsim rifles by Rap4 and similar companies. They tend to be better made (the paint, not the markers necessarily) and I've shot them fairly successfully on fields that allow it.

[Beemer]

Post from Deep Blue

I think this thread died because everyone is stuck on the dimples, which have been shown to not work, when the real point is the surface roughness in general.

a paintball with some surface roughness should have less drag than a smooth paintball, given that it's reynolds number is high enough to be close to the transition between laminar and turbulent. The roughness can be very small and come in many forms, not just dimples.

Spin has nothing to do with why surface roughness decreases drag. I have never seen anything in fluid mechanics that ties the effects of roughness to spin, in fact I have seen evidence against it.



this shows a smooth sphere and a sphere with a small wire (or possibly a thin depression) running around the front of it. The sphere on the right has a turbulent boundary layer and much less drag.

The keys here is that the sphere is not spinning (see the rod coming out the back to keep it stable), the roughness is small relative to the size of the sphere, and it is located before the point where separation would normally occur (separation occurs around 80 degrees from the front of the ball)

With dimples there can be many problems including poor contact between the paint and barrel. I don't know why dimples wouldn't work well, but they are not the only way to go achieve decreased drag on a sphere. something as small as the seam of the paintball, or a rough patch at the front of the paintball could cause the boundary layer to be transitioned to turbulent.

Someone mentioned lines scored longitudinally and laterally on the paint, this could be a good solution and one easily tested.

I think that increasing paintball range using this technology is possible and that it shouldn't be given up on, as it seems like it has (until it can be explained satisfactorily why it is not feasible)

A good explanation of the fluid mechanics involved can be found here however keep in mind that the lift in his diagram is purely from the back spin shown on the golf ball.

And another.......

The first one is the air flow over a smooth ball. The second one is air flow over a dimpled ball. The smooth ball has a larger area where the air seperates from the flow around the ball and it creates more drag. The more turbulent flow around the second ball has more air flow around the ball and less area where the air seperates from the air flow and starts swirling around and stuff like that, so less drag.

[thejere]

@Beemer

Your two quoted post make no reference to diameter. How do they advocate for either size?

The Reynolds number does help us make a fairly good estimation of drag but again seems to favor .68 cal over a .50 cal.

Reynolds = density * velocity * characteristic length / viscosity
The characteristic length would be the diameter of the paintball which is smaller for a .50 cal resulting in a lower reynolds and more drag due to laminar rather than turbulent flow.

If the argument is that the .50 cal are scored or roughed up in some way, why not score a .68 cal? Less retooling for manufactures and no equipment switches for players.

[Barsse]

Honestly, I think we're getting too hooked up on ballistics and physics to where it has little to do with the main point of paintball - FUN.

a) Paintballs are not meant to shoot far and straight. You want it - go join the army.
b) Typical field size is small enough tot he point, where the difference in drag on .68 vs .50 is really negligible, so why bother?
c) So you cna hit stuff at 100 yards? Do you often get a straight line of fire that long, and guys just stand open in the middle of the field or with their heads sticking out the bunkr waiting for your shot? Not on my field. We tend to need to run around, take cover, ambush, and bait them, and that's my favorite part.
d) Understanding how the paintball arches an curves flying from your particular marker is part of the game, part of the experience and part of the skill you need to practice. And an important one at that. you take hardships away - you lose the need to try to get better.
e) Camping always sucked and will suck for games, that last ~10-15 min, both paintball and online games. Even in scenarios - you need to rush the enemy. If the point is dead-on accuracy and range - game will be boring, with both sides in hide-outs waiting for someone to open up. Heard of trench warfare? Well, we don't have artillery, so it's just us.

CrapParts, First strike - I think they try to fix what's not broken. The game should remain a game, and a friendly at that, where, unline tourneys, opposing teams can sit and talk to each other after the game, instead of threatening and cursing after loss. Speeds and distances in paintball are far too small to require nearly as much effort in distance and accuracy as is being put into it. It's a sphere coming out of the tube, not hi--powered long-range ballistics. You want to get better with .68? - Don't change parts in your gun too often, and just PRACTICE with it, you wouldn't believe how well .68 flies in good and confident hands.

[Lohman446]

CrapParts, First strike - I think they try to fix what's not broken. The game should remain a game, and a friendly at that, where, unline tourneys, opposing teams can sit and talk to each other after the game, instead of threatening and cursing after loss. :

Its been years since this has been the case as it is

[Ninjeff]

Its been years since this has been the case as it is

i disagree. I played a 3 man tourney today where everyone, from teh top team to the last place team treated each other with respect and dignity. Yea, it was for money, but y'know what? none of the players made that a priority....everyone was generous, and respectful, clean, and had a blast.

Good tourney ball is out there, you just have to look for it.

[DamianTC]

"The Sporting Goods Manufacturers Association estimates that over 5.4 million people played the game in the United States in 2007, with over 1.5 million playing at least 15 times" - Wikipedia, Paintball

It took us almost 30 years to get to this point. So basically how long do you think it will take for players and field owners to buy enough equipment to allow 5.4 million people to play with .50 guns? And you can't say that .50 will be the standard and then say that .68 will still be around as well. That would be a double standard.

Remember, this is only one company producing this... Doesn't every company say that their newest product is going to "change the game forever"??

In my opinion though, a sport is that sport for a reason. Change something, and its not that sport anymore. Somethings are a certain standard so its not too easy, Why are football fields 100 yards? Why are basketball hoops 10 feet high? I like the idea of having to reload after 200 rounds and if you see the other team around 300 feet away that you have to work your way to them rather than sitting there and just shooting.

I feel the advancement of paintball has been great over the last 30 years, but I also think its gone alittle too far. If I was the king of the world and everyone had to do as I say (including you) I would have drawn the line in about '03 or '04. Keep everything at that standard..

Just remember, you change something too much and people start calling it something else.. thats why some people play baseball, and some people play softball.

[malJohann]

..Just remember, you change something too much and people start calling it something else.. thats why some people play baseball, and some people play softball.

..or Paintball and Airsoft...