When everything runs, this hopper feeds itself: a DIY centrifugal electric pump pushes ethanol to a steel engine burning gaseous oxygen, with servo-actuated half-inch valves metering both fuel and oxidizer, and a gimbal rig swinging the nozzle to demonstrate thrust vector control. The whole point of the project is a rocket that lands itself, which is an ambitious target for a garage effort.
The construction details are what grab me. The maker printed the pump impeller in aluminum and 3D printed the engine in steel, cooled regeneratively by the fuel, so in theory it should be reusable. The engine carries two attachment points for the TVC arms. The airframe stands on four long metal tube legs joined by 3D-printed parts with flat foot pads, with a silver cylindrical tank up top and a black tank below on a wired frame. A vertical stack of six blue and white components sits on a white printed bracket, and red and blue fluid lines run to the engine with wiring routed along the structure. Design work was done in the free version of Fusion 360, and a 3D printer produced the PLA parts.
The propellant choices look sensible to me. Gaseous oxygen was picked as the easiest oxidizer to buy, and ethanol is easy to get and simpler to handle; the maker ruled out nitrous oxide over the hazards of a self-pressurizing liquid at -70 Celsius. Notably, the ethanol is not pre-pressurized, the pump alone does the feeding.
There are open items, as expected at this stage. No static fire has happened yet, so chamber pressure and specific impulse remain unmeasured; the targets are 6 bar and roughly 200 seconds. The pump has run on water, most recently without its enclosure, and a full test is still to come. The engine will first be fired fixed before the TVC arms are used, and whether it survives without exploding is honestly still an open question.