The Idea

Armed with a worthy problem statement, we did what engineers do best – we held a brainstorm. The Oat Foundry brainstorm is of protected origin. Even though brainstorms seem loose and free-flowing, at Oat Foundry there are still rules! Quantity is better than quality. No judgment of ideas. No phones. We generated a wide range of concepts: using pressurized air as the launch mechanism, creating missile-shaped projectiles, building trebuchets, and many more. We settled on the concepts that would of course satisfy all of the requirements, but also be the most fun to build.

The Concept

With our concept in mind, we hit the drawing board. We started by weighing different materials that can handle high pressure. Stainless steel seems like a viable option, but can be expensive in the early stages of prototyping. We ran with PVC because it can handle high air pressure, is inexpensive, and can be easily cut and glued to mimic our concept sketch. The diameter of a bratwurst is typically 1.5” so a 2” PVC barrel worked perfectly. We stored the compressed air in a 4” PVC “tank” giving us plenty of volume for launch, and we bonded the barrel and air tank together with a ball valve that doubles as an air release mechanism. But how to shoot? This cannon needed a trigger. Air compressor → tank → trigger → boom.

Testing

We tried some dry fire shots to make sure the bonding and PVC could handle the high pressure, then loaded a traditional 6-inch frankfurter into the launch chamber and filled the air tank to 150 psi. FIRE. The franks flew fast enough to completely eviscerate the dog and target. We’re talkin’ ribbons of tubular meat. It was awesome. After several shots and air refills, a few flaws came to light. The bonding agent was unsafe to use after repeated use at high pressure, and we found the PVC material way too long and unwieldy. With these takeaways, we decided to upgrade: enter stainless steel.

Stainless steel can hold a higher PSI level allowing our launches to go much higher and farther than the PVC model, however, the stronger launching mechanism requires a casing to house the bratwurst so it can fly safely through the air. We used SolidWorks and our FormLabs 3D printer to iterate and create a “not a missile” casing for the bratwurst. The casing is 17 inches long and 3 inches in diameter; a perfect fit for the barrel of our launcher. The tail end of the casing holds a servo to release a parachute at the apex of flight so the bratwurst can slowly fall to the person on the receiving end. We reached heights as high as 200 feet with successful parachute deployments all while keeping the bratwurst safely (and edibly) intact. Hell yeah, stainless.

Served

At long last, we gathered the team, beers, our launcher, and of course, plenty of bratwurst to kick off Oatoberfest 2021: The Reckoning. We sang and drank as usual, but this year we shot and caught our beloved bratwurst. Our launcher saved us some trips to the grill, gave our yearly celebration a new addition, and ultimately made our socially distant Oatoberfest a success. The whole design turned out über cool. Check out the full video below.