Paintball mortars? Can it, has it been done?

[MoeMag]

Paintball mortars? Can it, has it been done?

I have a local scenario event coming up and I have been approached to make an artillery piece, due to my experience with potato guns. Is a high trajectory device ever been made and implemented successfully in paintball?

/\ /\ /\ for general discussion. \/ \/ \/ should be in deep blue but there is no one in there.

Mostly my concern is with the terminal velocity of a paintball. Once it reaches the highest point of its trajectory it will still maintain the same rate of de acceleration in the x-axis which is not a problem, but as it begins to fall again it will only accelerate to the paintballs terminal velocity along the Y-axis.
Does anyone know what this speed it, and how long of a free fall is required to reach that speed. More importantly will a ball break at that velocity?

[geekwarrior]

i think claymores would be more effect than a mortar....my friends tried the mortar idea with little success, turned out to be a better paintball shotgun than anything. The only way I can see it working is a larger size trajectory, like a water ballon filled with paint. You can get those slinshot things for them....but with mortars you really risk injuring somebody.

[MoeMag]

is a larger size trajectory, like a water ballon filled with paint..

[VFX_Fenix]

I'd look into using, as was mentioned, large caliber projectiles, like Water Baloons filled with paint or paint grenades (Squadbusters, Meteor Showers, etc) in sabots of something like paper cups.

A short barreled variant of common scenario bazooka/LAW/etc. launchers should probably do the trick if arranged in an "L" or "U" type configuration. I think the biggest problem you'll run into is just getting propper charge to get your projectile to travel a desired distance safely because of the small nature of such a device.

[geekwarrior]

yes, sorry, im tired

[PnueMagger]

I'm too lazy and it's too late to bust out the fluid dynamics text, but there is an equation that calculates the drag force based on shape, approximate surface finish, and density(or weight). Just google it. It's a simple force balance with the velocity on the drag coefficient side as the unknown.

[MoeMag]

I'm too lazy and it's too late to bust out the fluid dynamics text, but there is an equation that calculates the drag force based on shape, approximate surface finish, and density(or weight). Just google it. It's a simple force balance with the velocity on the drag coefficient side as the unknown.

Okay this is some reading for some other time than 1 am

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

Okay, so what is the minimum velocity needed for a paintball to break?

*Also apparently large caliber mortars are not allowed at many fields...

"1. Mortars are not allowed on NPA insured fields as the danger of knocking off a mask is too high and the price of an eye is too high." some pb tank website

It was and always has been our intention to use paintballs in a grapeshot style load... apparently due to this restriction, sorry guys.

[ThePixelGuru]

There's no way a ball falling can somehow pop from the speed. Only way to do that would be much greater acceleration, and paintballs can take upwards of 1500Gs.* It's seeing close to 0Gs when in free fall. Keep in mind that the horizontal speed will change, though - on a trajectory that long, air resistance will play a role in where the shot lands. Also, what are you going to use for a launcher? You're going to need something fairly consistant to have any hope of landing shots where you want them. As for terminal velocity, as long as it's not less than the muzzle velocity, the balls will accelerate to almost the original muzzle velocity by the time they hit the ground. If it goes up at 300FPS, it comes down at almost 300FPS.

* http://www.automags.org/resource/tec...rrel_eff.shtml

[MoeMag]

Found it!

Mathematically, terminal velocity is described by the equation



where

-Vt is the terminal velocity ~11.22 m/s... 36.8016ft/s
-m is the mass of the falling object... 3.5*10^-3kg
-g is gravitational acceleration... 9.8 m/s^2
-Cd is the drag coefficient... .07 to .5 for a smooth ball
-ρ is the density of the fluid the object is falling through...approximately 1.2 kg/m3. varying with pressure and temperature
-A is the object's cross-sectional area. (3.14159265359...)(.017272m)^2


For others information...
The terminal velocity of an object falling towards the ground, in non-vacuum, is the speed at which the gravitational force pulling it downwards is equal and opposite to the atmospheric drag (also called air resistance) pushing it upwards. At this speed, the object ceases to accelerate downwards and falls at constant speed. An object moving downwards without power at greater than the terminal velocity (for example because it previously used power to descend, it fell from a thinner part of the atmosphere or it changed shape) will slow down until it reaches terminal velocity. Thus a paintball that goes up at 300fps, will not hit going 300 fps... it could be faster but most likely slower.

****************
Okay this is assuming that the drag coefficient of a paintball is .5 (the slowest possible result), the terminal velocity is 36.8016ft/s (25.1 Miles per hour). Is that fast enough?

Its so late I could have screwed up the math... I will check it again later.

Thanks pnuemagger.

[buzzboy]

Go ask on forums.spudtech.com Those guys can answer any and all questions about stuff like that.

Have you come up with a design yet. I have seen many LAW/pbshotgun devices that use a 2" chamber connected to a 1.5 barrel by a pneumaticly actuated sprinkler valve. With that style gun you can lob paint onto a large group of troops or some people load them with twinkies to be shot at tanks(mmmm cream filling).

Will you be running it off of 12g co2's or through a remote line from a larger tank. The later option is usually easier becuase using 12gs requires a larger chamber so there is no overpressuration/rupturing.

[craltal]

you could always fire the little nerf-like rockets, but cut off the tip and slit it so a paintball will fit in the tip so a direct hit wil mark the target...

Helps discourage the "your rocket didn't hit me" especially when it's a different color paint than normal...

[Lohman446]

To simplify the question. As long as the projectile is fired on a balistic arch (not directly at the target) there is little concern of the initial velocity. The question is, falling from 300 feet (or 1000 feet high, or whatever) what is the highest speed the paitnball will reach from gravity. Is that speed safe and is it enough to break the ball? I understand the question, but do not have the knowledge to answer from a physics stand point Having fired balls straight up and watched them come down I would say yeh, they have adequate speed to break - I do not know if it is low enough to be deemed "safe" or under 300FPS. What is the terminal velocity of a paintball. Simple question I guess

[Major Ho]

From Tippmann Ordiance, been around for some time now, expensive:
"Mortar Launcher"



The M1A-M compressed air delivery device is a paint marker system resembling a military crew served mortar, similar in visual impact to a standard military 81mm mortar. The marker system is a smooth bore, muzzle loading, gas/Co2 operated, manually fired, high angle-of-fire training device. The device propels a marker round (water soluble marker paint), that produces a 70+ feet in diameter fragmented area. The device is made of all steel, with a cannon of aluminum. The device is shipped in a wooden crate with flexible handles on either end, which supports field transport and storage. The device consists of three components; cannon assembly, mount and base-plate assembly, and traversing and elevation (T & E) assembly . The cannon assembly consists of a barrel assembly and Co2 expansion chamber assembly with the upper base-plate and barrel-attaching bracket, charging valves, gauges and quick release firing valve (cannon is constructed of .250 thick wall aluminum). The mount assembly consists of a functional elevation control screw, traversing control screw and the bipod leg assembly. The traversing mechanism consists of the yoke and the traversing spindle assembly and mount which provides a functional traversing and elevation sighting system to provide functional indirect fire control. The base-plate assembly consists of a 12 inch by 12 inch by .250 inch thick steel plate with ground lugs and lower base-plate and barrel attaching bracket.
Ammunition for the M1A-M crew served mortar system consists of liquid fill contained in a latex tubing bladder encased in a cardboard and urethane cast shell casing.
Rounds are impact detonated causing casualties through simulated fragmentation effects.

They took away the pics of the actual rounds. They used a breakaway cardboard shell with a water balloon style innard.

[doc_Zox]

ball valve
yuk

diaphragm valve
yum

high pressure and PVC is a darwin call

run it at sub 80 psi and use a greater volume to push the sabot

my current test bed:


it does a 230 fps launch at 30 psi

[craltal]

http://www.rustyspaintballgear.com/rs/catalog/bytype.asp?type=Mortars