A Homebrew Rocket Has One Maker Constructing Thrust with Beer Kegs

Beer kegs ought to be capable to keep carbonation for weeks as a result of strain they maintain. Ryan and his group at Undertaking KegRocket checked out one and instantly imagined one thing fully totally different, similar to a pair of tanks containing the parts for an precise rocket flight. Early on, the group determined to make use of typical chrome steel beer kegs as propellant containers as a result of, let’s be sincere, they’re a handy start line.

One of many kegs has alcohol as gas, all pressurized and able to be pushed into the engine. The second keg incorporates liquid oxygen, the oxidizer, chilled to cryogenic temperatures. All the kegs are pre-built to resist significantly increased pressures than most of us would ever encounter, and their acquainted form is tough to beat. The ridges alongside the edges are additionally versatile sufficient to resist minor strain and temperature adjustments with out problem.

The large problem arises when it’s important to plumb the whole factor. Liquid oxygen is chilly sufficient to make common seals brittle and nugatory, so rubber O-rings merely fracture when issues get scorching. And, let’s be sincere, pure oxygen isn’t very best for a lot of supplies; they have a tendency to burn or fail. The group used metal-to-metal sealing every time doable. The plumbing’s spine consists of double ferrule compression fittings, 37-degree flare connections, and exactly chosen NPT threads. The place some flexibility is fascinating, stainless tubing can bend barely because the keg expands underneath strain and the LOX boils out.

The valves management the move with precision, whereas the primary oxidizer valve is a big industrial ball valve with a pneumatic actuator, a vented ball design to keep away from strain buildup, live-loaded stem seals, and a few fluoropolymer supplies able to dealing with cryogenic temperatures. The gasoline facet makes use of a regular ball valve from the ironmongery shop, nevertheless it does embrace a novel 3D printed bracket. You could have separate valves for filling the oxidizer, venting boil off gasses, and releasing extra strain by way of pop valves. Solenoids handle the pressurization utilizing nitrogen, which is fed by way of umbilicals that detach neatly at launch.

The whole engine is mounted on a bespoke thrust bracket fabricated from metal on a CNC utilizing plans given to JLC. It retains the plumbing neat and is sort of compact. The manifolds are merely carved from aluminum bar inventory and route the propellants to the engine in a tidy, pointed configuration. The LOX keg sits on high of the gas keg, offering some gravity help to get issues began earlier than strain takes management.

Security is clearly on the high of the record, correctly. The group strain examined the whole system with nitrogen, checked for leaks with a cleaning soap resolution, and glued the one minor one which appeared. To be on the protected facet, the crew solely goes as much as roughly 70% of the kegs’ ranking limitations, giving them a cushty buffer. On the bottom, you simply want two nitrogen strains: one high-pressure one for tank pressurization and one low-pressure one for valve actuators. When the rocket finally lifts off, there’s a helpful tear-away connector to maintain the umbilicals neatly organized.

This method takes a easy {hardware} design and provides a inventive engineering twist. The kegs function sturdy tanks, making it a viable resolution that didn’t require customized manufacturing. In the meantime, the plumbing system offers with the extreme chilly of cryogenic temperatures in addition to the tough process of coping with oxygen that has proven to be as reactive because it has. Earlier episodes on the channel confirmed the undertaking progressing from fundamental idea to setbacks, and naturally the same old suspects, integrating the avionics with the assistance of some companions, and finishing up smaller-scale testing similar to a liquid motor up in an airframe.

The fluid system has simply accomplished its strain and leak checks, and if issues proceed as deliberate, a static hearth would be the subsequent necessary step, adopted by the complete launch that the crew has been aiming for for the reason that starting.
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