The ballistics of humble potato is a time-honoured research topic for everyone who likes things that go bang. The focus of such work is usually on the launcher itself, with the projectiles being little more than an afterthought. [drenehtsral] decided that the wares of the local organic ammunition supplier were not good enough for him and his minions, so he designed and then 3D printed some rifled potato cannon slugs.
The design was done using OpenSCAD, has a number of adjustable parameters like infill and rifling. We doubt that the rifling introduces any spin, since it is being fired from a smooth bore barrel, but as always 3D printing brings the capability to quickly test different ideas. A quick search on Thingiverse shows a number of 3D printed spuds, so [drenehtsral] is not the first give it a go. However, this did bring to our attention that the field of spud gun projectiles is begging to be explored.
There is enough space inside a projectile to fit an IMU and logging electronics, which would give some very nice empirical data (providing you can recover it of course) on spin, acceleration, and trajectory that can be used to further improve designs. Spring loaded stabilising fins would be cool, and maybe someone can even manage to implement some form of guidance? The possibilities are endless! If you’re up for the challenge, please document your work it and let us know.
As you would expect we have no shortage of potato cannon themed content, ranging from cartridge firing and bolt action versions to antenna launchers and Arduino-powered fire control systems.
In Norse mythology, Mjöllnir is the hammer of Thor, forged in a contest to create the most wondrous and munificent tool for the gods of Asgard. While we’re not aware if [MrCrowley] recently made a bet with Loki, his version of Mjöllnir, a gigantic spud gun powered by MAPP gas, is wondrous enough for our tastes.
Unlike most of the other spud guns we’ve seen, [MrCrowley] eschewed the use of PVC pipe and fittings in his build because that would explode on the first test fire. Instead, the gun uses galvanized and stainless steel for the majority of the construction. That’s not to say this spud gun is necessarily safe, though: as he demonstrates in the video after the break, golf balls exit the barrel with a comparable energy to most rifle rounds.
For an interesting take on an ignition system, [MrCrowley] built a remote ignition system out of a wireless doorbell and a 100kV stun gun. While this does allow for remote firing, the entire build seems safe enough – from behind the muzzle, at least – to be carried with a rifle strap.
It should go without saying that this is incredibly dangerous and you shouldn’t build this if you’re not planning on your last words being, “Wanna see something cool? Hold my beer.” That being said, [MrCrowley] knows what he’s doing, and you can check out the video of Mjöllnir in action after the break.
Continue reading “The Spud Gun To End All Spud Guns”
There’s nothing quite like [Elliot]’s cherubic sense of wonder and maniacal laughter after he tests his fully automatic AA battery-launching air gun. That fires 600 rounds a minute. At 200 feet per second.
We need to take a minute and say [Elliot]’s gun is stupidly unsafe. He used PVC pipe to hold air pressure, so that may… explode one of these days. Also, the AA batteries coming out of the end of the barrel have the same kinetic energy as a .22 rifle bullet.
The mechanics of the gun is a simple blow forward bolt. When he pulls the trigger, the bolt – and battery – are forced forward due to air pressure. After the bolt has cleared a plug, air is allowed to flow through the bolt pushing the battery along with it. Once the pressure in the barrel is back down to normal, a spring forces the bolt back into place and the 23 round magazine loads another battery. Simple, really. [Elliot] posted some pics of his gun on the spudfiles.com forum.
The gun is accurate to about 100 yards. It’s a very impressive piece of engineering for a bit of PVC pipe, but we don’t feel the need to copy this one. Check out the videos after the break to see this thing in action.
Continue reading “DO NOT Build A Fully Automatic Battery-launching Air Gun”