Propulsion Engineer
Poseidon Aerospace
Propulsion Engineer
Poseidon Aerospace
Develops uncrewed fixed-wing cargo aircraft
Poseidon Aerospace is reimagining how the world moves goods. We build and operate full-size autonomous cargo aircraft - 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 the San Francisco Bay Area with locations in Washington DC, Oregon, and Maine; we're building something consequential.
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.
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 propulsion system improvements and validation in a safe and traceable manner.
Translate & Present findings: Distill, document, and present data to validate requirements, limits, and drive design changes. Work closely with other teams to refine and improve propulsion systems.
Refine & Develop the break-in, operating, inspection, and maintenance procedures: Document and collect the procedures that carry the propulsion systems through test stand runs, ground runs, and flight tests.
Applied tuning of standalone/aftermarket ECUs: Fuel and ignition mapping, idle and transient control, drive-by-wire, knock, and sensor/DTC strategy.
Strong conceptual and hands-on knowledge of 4-stroke piston engines
Engine test-stand or dyno experience: Experience building or running an instrumented cell, including thrust/torque measurement, cooling and oil-system instrumentation, and DAQ.
Working knowledge of aircraft propeller and constant-speed governor systems.
Sharp diagnostic, setup, and troubleshooting skills.
Familiarity with controlled assembly and maintenance standards: FOD prevention, tool management, and shop safety.
Hands-on experience tuning, calibrating, and bringing up EFI piston engine systems: Aviation, motorsport, engine-swap, or standalone-ECU backgrounds are strongly relevant.
Experience qualifying or validating engines on a test cell, dyno, or test stand, and ideally through ground and flight testing.
Practical knowledge of aviation and automotive fuels (AvGas, MoGas) and their effect on calibration.
Comfortable working at the bench and on the aircraft, with strong, self-directed troubleshooting instincts.
Strong collaboration skills to communicate verification findings and design feedback clearly across disciplines.
Competitive salary and meaningful early-stage equity
Relocation support if applicable
Low-ego, collaborative workplace culture
6% retirement matching
Unlimited PTO
Free lunches, snacks, and a stocked fridge at our offices
AI tools and subscriptions
Competitive salary and meaningful early-stage equity
Relocation support if applicable
Employee Health Benefit Plans
6% Retirement matching
Flexible PTO
Free lunches, snacks, and a stocked fridge at our offices
AI tools and subscriptions
Develops uncrewed fixed-wing cargo aircraft
Poseidon Aerospace designs and builds unmanned fixed-wing cargo aircraft for defense and regional commercial air cargo. Its planes are combustion-powered and designed to shed crewed freighter mass (no cockpit or life-support) to improve payload-to-empty-weight and reduce operating costs, with variants including the Egret and a seaplane variant called Heron. The company uses a demonstrator (quarter-scale Seagull) and aims to mature to full-scale aircraft that can operate on remote routes with degraded infrastructure, rather than pursuing electric or hydrogen powertrains. Unlike many competitors, Poseidon plans to run its own regional cargo service instead of selling aircraft, focusing on remote, underserved corridors and a pilotless, hub-to-spoke model. The goal is to achieve a first full-scale Egret test flight by the end of 2026 from Alameda, followed by establishing a regional cargo operation to serve those challenging routes.
Explore more opportunities at Poseidon Aerospace