Calling all forward thinkers - Looking to design almost completely 3d printed cannons

Anvil, if you don't want to use CO2 have you considered using an air compressor? A standard 12v bicycle/auto air compressor is able to produce the pressures needed, and a pressure switch can be used to shut it off at the desired pressure. Strip one down and you've got a compact, unlimited source of air. That mechanism was used by big gunners long before CO2 and freon, and is the origin of their rate-of-fire restrictions today. Heck, I have two destroyers that use a schraeder valve fill port for their single-shot torpedoes. It does have issues (noise, vibration, complexity) but it is a functional, proven alternative to CO2.

I have played around a little with the airsoft cannons in RC tanks, and this is what I learned. Airsoft cannons are able to reach a high velocity using several tricks. First, they use relatively long, large-bore barrels with very light projectiles. 6mm plastic shot is much easier to accelerate than 4.5mm steel bbs. Second, they use the air much more efficiently than we do. The piston, shot, and barrel are all in line, and there is no expansion volume between the shot and the piston. Once you introduce a direction change, or even an inch or two of space between the piston and the shot, and you lose a lot of efficiency. Lastly, they are using injection-molded plastic pistons and cylinders, which are much smoother than the rough, layer-ridden surfaces of FDM printers. That makes for a better seal and smoother movement. While that can be overcome, it is another issue to deal with. Maybe in a 1:72 scale or 1:96 scale cruiser, where you have much more room in the turret. Or perhaps in a destroyer, where you can hide most of the operating mechanism in the superstructure and just have the barrel poking out.

 

depends on if you're looking for Fast Gun or Big Gun. We now have several excellent examples of Fast Gun cannons. My SMS Deutschland uses 3d-printed cannons exclusively. No available designs for Big Gun cannons though.

 

Interesting. Yeah I am setting up an air compressor rig for bench testing as soon as I finish buying a house. I was more looking at getting rid of air tanks and solenoids completely. Too bad the airsoft compressors won't work in our application.

 

Jeff K has a viable design that uses. Not purely 3D printed but close. Last I talked about it he was getting it dialed in and confidence was increasing that they were safe to share.

https://rcwarshipcombat.com/threads/3-d-printed-alabama-big-gun.445862/#post-526096