Desk top slingshot cannon (1:10 scale)

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JoergS

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OK, as you may know I am planning to make a petanque ball shooting carriage mounted slingshot cannon. The goal is to shoot the 3" (8cm) (800 gramm heavy) steel ball with 70 m/s, almost 2000 Joules of energy.

So I wanted to do it like the Mythbusters and started out with a 1:10 model of it. This means the ammo has got to be 8mm steel as the petanque ball is 80 mm steel.

I have to say that working on such small mechanisms is not easy, in fact it is a lot easier to work big size. I am not totally happy with the precision of the job, but it is functional, even dangerously so. It fires 8 mm steel balls through a few layers of tough cardboard (moving boxes).

I have changed the lock mechanism, made it more sturdy by adding two more lock arms on the opposite side. This gives the lock arm much less play.

Have completed the model weapon now, including a second winch to adjust the shooting angle. This needs some finishing work and is ready to sit on my desk!

The "real" version will be almost 4 meters in total length.

carriage3.jpg


carriage2.jpg


carriage1.jpg


Here is the video:

http://www.youtube.com/watch?v=TZ9keWOP2To
 
I always love your posts and creations Joerg. You make some of the coolest stuff!
 
SO we had friends over last night and trying to show Alan Joerg's work we came across the new 1/10 scale video. Naturally my son sneaked in and watched over our shoulders. There was great excitement by all. Your work is fantastic.

Friend Alan picked up a piece of Orange Thera band from my desk and twisted it and got an odd look on his face. So what would be the effect of twisting full width thera band into rope like lengths and then taking three and braiding them together like a girl's hair?

I do not have enough of the stuff to try it. Alan suggested giving each strand the same number of twists and holding them on some sort of frame to prevent un ravelling and then brading three together for a "super band."

I ended the evening by digging out a Powerline by Daisywith foldein arm rest with the surgical tube that came on it (I know you serious sling shot guys sneer at toys) and shooting a bit, the high point of which was shooting a quartzite pebble at a sharp angle on to our concrete drive way and watching the flash and hearing the richochet sound angling off into the darkness.

PS (edit) Just went out with my son and the Powertline and some glass marbles. Son shot through one side of an aluminum soda can filled with water and dented the other side. Of course he was only about two meters from the target as this was his first try at a slingshot but he is now thrilled and I must build some sort of back stop that saves anx returns his ammunition. Marbles striking the styrofoam block archery target are obsorbed to deeply to touch and those that strike haybales are just gone.

-kBob
 
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As a scale model, that looks pretty good. Otherwise, for the life of me I cannot think of any reasons to have a "desktop" slingshot cannon. I don't have any place where I have a desk that I could shoot one of those things. LOL.

Now, if you could make an adapter so that I could shoot it out of my driver's side window on my truck, we would be in business!
 
Have now oiled it with red-brown stock oil. I think it looks much nicer now!

cannoncolor.jpg
 
Really cool!

So in essence, your big summer project is a Roman Carroballista, just with much more efficient rubber instead of skein-torsion levers. Now that will be a sight to see. Just pray the government doesn't get too nervous and rewrite their artillery restrictions.
 
I don't usually comment on your threads, Joerg, but it's awesome to see someone so involved and excited by their hobby. The designs you come up with are amazing. Can't wait to see the full-grown version!
 
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