Propulsion Engineer

ABOUT POSEIDON AEROSPACE: Poseidon Aerospace is reimagining how the world moves goods. We build and operate full-size autonomous cargo aircraft; Heron, a seaplane, and Egret, a STOL aircraft; each capable of carrying two tons of payload over a thousand nautical miles. From remote communities to contested logistics operations, our platforms unlock a new cost curve for air freight, making it faster, cheaper, and accessible anywhere it's needed. Headquartered in San Francisco with offices in Washington, DC and Maine, we're a small team building something consequential. ABOUT THE ROLE: As a Propulsion Engineer at Poseidon Aerospace, you will lead the propulsion team’s development from initial assembly and bring-up to a fully calibrated, instrumented powerplant ready for flight. This is a hands-on role centered on engine assembly, design, tuning, and qualification via testing. You will run engines on the test stand, develop test procedures, prove they meet performance and durability targets, and collaborate cross-functionally to iterate and improve on the propulsion system. If you have an interest in aviation, working hands-on in a test environment, motorsports or high performance engine tuning experience, and have strong instincts running an engine test cell, we are looking for you to join Poseidon. RESPONSIBILITIES - Calibrate the engine across the full aviation operating envelope: fueling, ignition, idle stability, transient response, knock, and closed-loop strategy on a standalone ECU, with the propeller governor tuned to performance and reliability targets. - Run the engine test program on an instrumented test stand: break-in, bring-up, performance mapping, and endurance/qualification runs that prove each engine flight-ready. - Bring up the integrated engine from assembled hardware through verification: Outfit assemblies, prepare systems, diagnose faults, and close out anomalies. - Operate test instrumentation and DAQ: Specify and collect required data to drive prop