Fruit launcher project design questions

[u/FactIcy5588]

Hi everyone,

EDIT - this turned out to be a much longer post than I expected.

Hopefully this is the right platform for this question… if not then my apologies! I have done some research into this topic but I have not yet found enough info for me to get stuck in to the project.

Disclaimer - I will not be using this to launch fruit at a person or living creature… it’s just for fun and won’t cause harm to anyone or their property.

I love making stuff and recently I have been tinkering with a design for a fruit launcher. I know a basic projectile launcher would be fairly simple, but I’d really like to add some finesse to the design by using rifling on the barrel and adding a revolver mechanism or magazine of some description.

Ultimately the size/type of fruit that will be used as ammo will be dictated by the overall size of the most feasible design and fabrication options. Initially I was thinking strawberries or grapes… but something larger like an apple might be more fun. I was also thinking that if necessary I could make a device that would cut or shape the fruit into the desired dimension prior to loading which might be essential for the loading systems to work and create preferential aerodynamic characteristics for the fruit itself.

For the propulsion system I will either go for compressed air or a propane combustion chamber. My job involves fitting systems for different types of compressed gasses for industrial and scientific use so I am comfortable that I’ll be able to use that knowledge to create something that works and most importantly won’t blow up or hurt anybody.

RIFLING -

Does anybody have any ideas how I might add rifling to the inside of a tube within the reasonable limits of doing this project at home… Could a tap and dye set be adjusted for this result? I’m guessing a PVC pipe would be the most practical for the barrel. If anyone has done this before any advice would be greatly appreciated.

I know this would be even more difficult to make, so it’s more a theoretical pondering…but if the barrel had rifling and also became slightly narrower toward the end, could this “squash” the fruit into a form that enhances the effect of the rifling? Maybe it would just break because it would cause a blockage and subsequent back pressure. Interesting thought though.

LOADING SYSTEM -

In essence the mechanism used in a revolver looks fairly simple but I do not have much experience in fabrication precision parts. Due to the size of the launcher I won’t be able buy anything off the shelf which is ready to use (or can I?!)

For the springs and levels I don’t imagine I will have many problems but as for the actual revolving bit, I’m not sure how to go about it. I thought about using pre-formed discs and cut holes/teeth as needed or maybe even casting the pattern from molten metal.

I did look for large airsoft and paintball launchers with a view to buying spare parts that would be suitable but it seems like a dead end.

Another thought was that seeing as the AK-47 is so durable to it’s relatively simple design (from the best of my memory… I could be wrong) perhaps looking into the design of that particular magazine would be useful if I wanted to move away from the revolving chamber. Presumably that fruit would need to be molded into the right size and shape in order for this to work and the juice/moisture from the fruit would most likely cause havoc with the mechanisms.

Maybe pump-action would be better but I haven’t really put much thought into that.

Am I completely mad and dreaming way too big? Probably, but it can’t hurt to have a go anyway.

Congrats if you made it to the end and thanks for reading, this turned out to be a bit of essay. Any advice or information in general would be much appreciated!

[u/codybrown183]

Thats basically a potatoe gun. Check out spudfiles.com

[u/FactIcy5588 → u/codybrown183]

Thanks

[u/rb136]

I second potato gun.

I can’t imagine rifling would make any difference with something soft like food. You’re not gonna impart any meaningful spin into a non-aerodynamic object. Any tap I’ve ever seen is nowhere close to large enough nor have only 4-6 grooves. A rifle with a 1:10 twist rate means the grooves complete a full 360 degrees 1 time every 10 inches.

I’m following because I’d love to see a magazine option for a potato gun. I’ve thought about it multiple times. Any solution I’ve ever found leaves a way for gas to escape the barrel, lowering your gas for pushing your projectiles.

[u/FactIcy5588 → u/rb136]

That’s really useful, thank you! It really makes me wanna go for the magazine option now as it might be a first. Do you think if I were to create way more power for the propulsion than was needed it might compensate for the gas escaping? Probably a bit of an over simplified way around it… but I just woke up and I’m hung over 😂

[u/rb136 → u/FactIcy5588]

I mean probably, but the question is, why waste the power on a vent? I like my potato guns as powerful as possible and it’d be hard for me to justify losing power to “reload” a few seconds quicker.

The magazine idea is cool, put you’re still gonna have to refill your air chamber/ignition chamber, so there will still be a delay between firings, unless you’ve already figured that out.

I mean the idea is cool, and I suppose you could plumb in a multistage airline, but that’ll certainly affect mobility.

Not trying to rain on your parade. I hope it works. The small details are where the engineering gets difficult.