Siege Weapon??

[DeadlyTao]

Well... outlook is grim. For the past months I have been trying to design and test the concept of a sling shot artillary analog for paintball games. The goal was to send a balloon with .5 liters of paint inside of it to somewhere 400 meters away (~1/4 mile).

However... after a dissapointing concept test, to determine if the force/load ratio or the length of draw is more important, I decided to take back to the webs to find out if rubber can launch something that far in the first place. After searching the obvious areas, like pumpkin chunkin', I could find naught but one result, which came up as 200-300 feet (not enough...).

So I want to ask if anybody here knows of a successful siege style long-distance slingshot. Also, and perhaps this would be even more helpful, if anybody knows of the maximum launch velocity (as if it was dry fired) of the very best latex bands. I have heard that the best are the therabands, in which case thinner is better.

Money is no object, if theraband can get to 250fps, then I can get it to 250fps, despite the mass of the ammo, so long as my theories are correct.

[skit slunga]

You need to research 'ballista' (http://www.google.com/imgres?imgurl=http://members.multimania.nl/onager/BallistaPic.jpg&imgrefurl=http://members.multimania.nl/onager/ballista.html&h=427&w=361&sz=27&tbnid=ekAyG1DkfR9koM:&tbnh=244&tbnw=206&prev=/images%3Fq%3Dballista&usg=__sZILw29tq0hM3kWbZXtLYtpURxQ=&ei=_uLpS8T6DcL58AbWysXlDg&sa=X&oi=image_result&resnum=1&ct=image&ved=0CCgQ9QEwAA) 'carrobalistae' (http://members.multimania.nl/onager/cheiroballista.html) and 'onager' (http://www.google.com/imgres?imgurl=http://members.multimania.nl/onager/OnagerPic.jpg&imgrefurl=http://members.multimania.nl/onager/onager.html&usg=__3wRjHfVDKB2Hb1sjse8eoPYytvE=&h=383&w=600&sz=119&hl=en&start=3&um=1&itbs=1&tbnid=gZ0hkzgI5SF8JM:&tbnh=86&tbnw=135&prev=/images%3Fq%3DRoman%2BOnager%26um%3D1%26hl%3Den%26c lient%3Dfirefox-a%26sa%3DN%26rls%3Dorg.mozilla:en-US:official%26tbs%3Disch:1) . I believe the carroballistae will get the range you need.
The difference for your application is the ammo and the propellant . You can replace the "torsional limbs" with a pulley system that uses latex tube or bands. Then...portability :eek: this ain't gonna fit in your pocket...or trunk- it may fit in the bed of a pickup though :D

"The ballista came in a range of sizes with varying ranges. A ballistae bolt could be fired anywhere from 300 yards (275m) to 550 yards (500m). It was loaded with a 3 ft (100cm) bolt that could be fired at up to 115 mph (184 kph)."

[Jaybird]

We had a tree service slingshot at the tournament that shot golf balls up in the air out of sight.It was more like a mortar than a field gun.Would something like that help you?:)

[DeadlyTao]

That's very helpful as far as motivation goes. I am glad to know that the concept is at least thinkable.

The design I have going in my head so far is something like an 'M', where there are two long arms with pulleys on on end (these are the sides of the 'M' and the pulleys are at the top corners). On the outside of the arms there is elastic attached, which the goes forward, around the pulleys, wrapping inward and connection with the pocket between the pulleys. The elastic is pulled back to form the 'M' shape and the projectile is shot forward the direction the arms are pointing.

The reason for the elastic wrapping like so is that I can put pretensioning arms (arms that will pull the elastic farther down the outside edges of the arms before pulling it back) which will add stability and easy of resetting to the large bands and, most importantly, stop the pocket at the end of the arms by providing force against it moving forward or back after released (safety feature).

I am hoping that these pulleys will give it more energy by allowing me to stretch the elastic down the arms twice. I will add pictures of real engineering sketches and drafting when anything is complete, but I am still in the concept and brainstorming stage.

[skit slunga]

Is this similar to what your "M" shape could be? I realize there isn't the greatest detail in these pics I've gleaned from the net (ie not mine ). I recalled this "ballista" from the 80's - in order to achieve the distance requirement it would need to be a bit larger in size than a normal self cocking crossbow. The concept is out there and was commercial. I recall them advertised at @$180. Wished I'd have bought one new.
clicky to embigganate.

http://i948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/th_a520dcaa.jpg (http://s948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/?action=view&current=a520dcaa.jpg)
http://i948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/th_59a5b569.jpg (http://s948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/?action=view&current=59a5b569.jpg)
http://i948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/th_5dce299e.jpg (http://s948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/?action=view&current=5dce299e.jpg)
http://i948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/th_f25d5a80.jpg (http://s948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/?action=view&current=f25d5a80.jpg)
http://i948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/th_f3ff5539.jpg (http://s948.photobucket.com/albums/ad326/Skit66Slunga/others%20shapes/?action=view&current=f3ff5539.jpg)

use cam style pulleys... will add to an easier final draw and possibly some decent forward inertia
http://ezinearticles.com/?Compound-Bow-Cams-Explained&id=2881146

[wilbanba]

awesome idea
id consider a modification of the sling king with wider forks and larger pouch or the 3-person style water balloon launcher with shortened tubes so you can put each "handle" around your feet and launch from a reclined (back on the ground) position for one person operation or leave it standard and enlarge the pouch for standard fire.