The detail that jumped out at me first is the exhaust: the nozzle on this motor throws off clean supersonic mach diamonds. The maker reports this was the first mathematically optimized nozzle design to produce the diamond pattern, and that is a strong result for a small test motor. The expansion ratio was tuned mathematically for the chamber pressure, so those diamonds are not luck.
The motor, called Test Motor-1B, is a hybrid burning paraffin wax loaded with micron scale aluminum powder against gaseous oxygen. The hardware is straightforward: a metallic tube casing holding a central fuel tube, closed off with metal end pieces and a metal nozzle. Ignition is electrical, and the whole assembly is held on a horizontal test stand with adjustable hose clamps. Firings were run outdoors over asphalt.
The test matrix is what really stands out. Four fuel mixes were fired, with aluminum mass fractions of 0, 3.05, 5.83 and 8.50 percent. Total impulse climbed from 57.07 to 88.75 newton-seconds across the series, while peak thrust stayed between 22.11 and 24.68 newtons and burn duration ranged from 3.10 to 4.38 seconds. The thrust-time curves were produced with CURVE.
The aluminum clearly adds energy and impulse, but it also slows the regression rate and stretches the burn, a genuine trade-off sitting right in the open here. This motor is a development step toward a high-powered rocket producing up to 1kN of thrust. The ignition sequence is worth reading too: a 10 second oxygen purge, a potassium chlorate charge lighting the surrounding wax, then throttling up by raising the oxidizer flow rate.
Project by Canadian Student Space Initiative. Watch it on their YouTube channel: