All you engineers....

tres

tres

tres

Soldato
Joined
16 Oct 2007
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On Saturday, some friends made a tennis ball cannon.

4 foot of pipe as the barrel, attached to 4 food tins (tops removed and most of bottoms) as the chamber.

Shoved a tennis ball down the barrel (very tight fit)

Right at the bottom can, they made a small hole which they squirted in a tiny bit of lighter fuel. Lit the hole, resulting "whoooomp" noise shot the ball about 200metres. Awesome.


Now, we've got a bit of a competition. Varying designs etc.

Any hints or tips? For anything - design, fuel mixture/amount etc etc greatly recieved! I start mine on Thursday, video will be done
 
I have it on good authority that making a potato one is much better, and that cheap hairspray makes the best propellant. You only need a brief squirt.
 
we've gone for tennis balls due to uniform size, easily available and fair in testing results!

Cheap hairspray eh? Shall try that next!
 
Make something out of uPVC pipework. I've got one downstairs in the garage,

Unfortunately I don't have time to type it all out,

Have a google for PVC Potato gun, Its easy to work out/make :)

Hairspray is good, but makes the inside of your gun all sticky. I started using 'Easy Start' as the propellant, it contains Ether, worked v.well.
 
I made one with a mate a few years ago.

-Longer barrels = greater muzzle velocity + accuracy (up to a point, obviously)

-Propane/butane make very good fuels. You can use a blowtorch canister to get these, and only a very short squirt of fuel is needed.

-Make a decent ignition by using a disposable camera flash for the spark. You can also use a BBQ lighter poking through a hole in the barrel.
 
Hairspray is the easiest way to do it.

Compressed air is also good, but more difficult to build. (Johnny69 on here made one and posted the results)

Experiment with different fuels and barrel lengths.
Maybe you could also try soaking the tennis ball to get a better seal with the tube?

And post some pics.
 
Without knowing lots of details its impossible to give exact advice.

You'll have to spend a while doing trial and error with the fuel mix

-too much and the combustion will be 'rich' resulting in unburnt fuel (black smoke) and reduced power output - some of the energy will have gone into heating the unburt fuel and ejecting it along with the ball.

-too little and although combustion will be complete the ball wont go as far, due to less energy being released.

somewhere in the middle is obviously is best!
Lighter fuel will be a better proppelant than cheap hair spray due to a higher energy density, but it is much more expensive and harder to get a clean burn from, so using the butane gas in cheap hair spray will probably be easiest
 
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mate of a mate welded up a silly potato cannon of death. after tonnes of hairspray and firing potatos silly distances it supposedly started getting boring

so added a bit too big a dash of oxyacetylene... only took the bomb squad about 15 minutes to arrive.
 
"andy" said:
mate of a mate welded up a silly potato cannon of death. after tonnes of hairspray and firing potatos silly distances it supposedly started getting boring

so added a bit too big a dash of oxyacetylene... only took the bomb squad about 15 minutes to arrive.
Click to expand...

explain more please :)
 
I believe Johnny69 is the man you want for somewhat crazy homemade weaponary!

Fairly sure it was him who made the compressed air potatoe launcher.
 
just used the designs you can find all over the net for potato cannons, i think they showed how to make one on braniac and other programs like that too ? but instead of using cheap pvc pipe youl need to use steel pipe and fittings

theres vids of people doing the same on youtube. except theyre doing it in the middle of nowhere rather than on a council estate . the noise is supposed to be ridiculous. ears ringing for rest of day sort of bang. he never got charged by police but easily could have done because i guess its probably classed as a firearm
 
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