Project Death Weapon

FrostedNipple said:
lmao at this thread, errr, i haven't managed to got the tube on yet, it need welding, and im no good at it, so i shall get my dad to do that, although, i did pump the air tank up to 40psi in 5 mins, and it makes a loud noise when its all released :D will get pics of the tanks and valve attached tomorrow, im on study leave so i have nothing better to do other than shower and get dressed :p
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OK dude, some good advice as i have a LOT of experience in firing golf balls with an air cannon. Our 4th year group project (MEng in Mechanical deisgn + materials engineering course) involved the production of an air cannon to fire golfballs (not saying anymore ;) ).

Right firstly, don't make the tube too narrow so the golf ball only just fits down it. You want a tube with approximately 4-5mm larger in diameter than a golf ball. This creates a cushion of air that effectively lifts the ball off the inner tube and propels it out with no friction against the inner tube. We were only running at about 6 bar, but could fire our ball 200 yards up a hill, at about 45 degree angle. But we were using a £400 fast acting open-close valve to fire the thing.

It's great fun, but for the love of god be careful. Golf balls flying at 50+ m/s are stupidly dangerous and the shear amount of safety switches, risk assessments, perspex panels, and cages we had to put around our pre-tube air chamber and cannon exit really were justified.

Now all the boring stuff is over, go have some fun :D
 
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thanks, for the above post :) the pipe i have at the moment is slightly too big, i was going to use 2 bits of shaped plastic to keep the ball in the center and make the tube air tight, I'll have a play around with the tube to find the best combo. As for safety measures there aren't any, my dad said he could take it to work and pressure test it, not really sure what that means but its sounds like it makes it safe :p the air canister is rated to 1000psi, valve is 100and something, so its all reasonably safe anyway :rolleyes:

I'll get some pictures today, unless my dad has taken it all to be pressure tested, in which case I'll get the pics later tonight
 
When I worked underground we used air cannons on solid-feed silos to keep product flowing in nose cones. We rigged a spare cannon up the the pressure/timer control and welded a tube onto the end. We managed to fire a fair distance, but it was just a bit of fun. Worked a lot better than the actual air cannon we had rigegd up on the silo though.
 
Nice plan... though I would have thought the best method for getting it as far as possible would be really boring. Hot air baloon would quite happilly transport a golf ball miles.

Alternatively cut a hole in the second tank and fit a spark plug, then weld on your launching pipe... fill the gas canister with the right air/gas mixture and BOOM. Would expect you to be able to get a pretty good muzzel velocity with that ;o)
 
100PSI is pretty damned high for that size of projectile :D although the flow rate through the valve will be your main problem.

The materials of your "gun" is made of could be the limit of the maximum pressure you could safely work with, so keep that in mind :)

Nice project!
 
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there it is with the tube on, i powered it up to 20psi and whacked in the golf ball, got it into my hedge, which was 2 meters away, i would have kept going for quite a bit :p

I'll try to get a vid later on :)
 
By the way I'd recommend you fire it into something solid, through a hedge it could end up going through the other side and hitting someone, take the same precautions that you would firing an air rifle or something similar.
 
Andelusion said:
By the way I'd recommend you fire it into something solid, through a hedge it could end up going through the other side and hitting someone, take the same precautions that you would firing an air rifle or something similar.
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are you not aloud to fire an air rifle through a hedge???? :confused:
 
Nice one mate!

I used to work in special effects and we made a few of these for firing bigger stuff. If you can lay your hands on a bigger ball valve it will work better as the air will come out a lot faster!

The smaller ones we made were for firing fruit and stuff and would shoot a watermelon or a big bag of fruit about 100 metres. That was a bit bigger than your bottle there, we used a steel sphere mounted in a frame with a 2" ballvalve and we pumped it up with 250psi of nitrogen or CO2, whatever was to hand. Just released that one by hand because it wasn't too scary.

The bigger one was a 6 foot tall nitrogen bottle with a 4" ball valve welded in the top which we filled with 1750psi of nitrogen. CO2 doesn't go that high. That was mounted in a huge steel cage with a 4" diameter nozzle which we used initially to launch big stuff into a field and it fired a 125Kg frame over 300 metres. This one we got a digger in anf stuck it down a hole because we didn't want to be anywhere near it if it exploded at that pressure. We'd load it up, hide behind the mound of earth and pressure it up. The crew were evcuated to a safe distance while we did this.

The second series we used it to fire cars off the end, namely an Escort van with a cage welded into it and that was shot through dummy buildings and it was used on one of those Top Gear videos to launch a car off a cliff. The welds eventually went and the nozzle tore itself out the frame and flew about 50 metres behind the the cannon itself. This in itself weighed about 75Kg but we had the pressure right up for that one :D

Yeah so get a bigger valve and send them suckers flying properly :D
 
Oli (frostednipple) you didn't tell me you got this far, I might come down tomorrow and help out, lol I feel left out otherwise :( , baggsy the first shot at school, lol dobson will poop his pants when we fire it :D
 
You might want to replace that foot pump with one of the 12v electric pumps that are available. Some of those can get over 250psi. :D
 
95psi isnt much at all especially when quite a bit is going to get wasted.

poor a couple of litres of diesel into the tank and just keep cranking up the pressure with the biggest foot pump known to man.

trust me itl be fun.
 
The problem is, we have to pump it up manually, there are no electrical devices or chemical reactions aloud :( .

On the knowing how far it goes part, we are going to fire it across our school field. :D
 
This will fire a golfball so far that you can't actually see where it lands, just powered with hair spray as well.

Be careful where you're playing with this though, I had 2 of Durham Constabulary's finest armed response officers come and tell me ever so politely that I wasn't allowed to play with it. They were impressed with how far it could fire, though :D

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neil-ste said:
This will fire a golfball so far that you can't actually see where it lands, just powered with hair spray as well.

Be careful where you're playing with this though, I had 2 of Durham Constabulary's finest armed response officers come and tell me ever so politely that I wasn't allowed to play with it. They were impressed with how far it could fire, though :D
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Heheheh, here's a sneaky pic of my current toy:

cannon8.jpg


With the drainpipe barrel (which isn't in there yet) I'm going for a 1/2 kilometre with a tennis ball. My shorter one went 350 metres and this is a fair bit longer :D

Build pics are going on here when I get around to finishing it off, proabbly this weekend. Runs on Zippo lighter fuel.

Edit: you need 8 baked bean tins so get them ready folks :D
 
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