Propulsion Development Engineer

Hermeus is a venture-backed defense aviation company reclaiming the lost art of rapid iterative prototyping to build the fastest aircraft in the world today. By prioritizing relentless hardware iteration, we deliver high-speed systems at the pace of the modern battlefield. We work with the Department of War to provide the high-speed capabilities our nation and its allies need to maintain a durable, asymmetric advantage.

About The Role: As a Development Engineer on the Propulsion team, you will be responsible for advancing engine hardware through rapid, test-driven iteration. You will operate at the intersection of hardware execution and data analysis, owning engine test campaigns and translating results into actionable engineering improvements. This role requires strong hands-on capability, analytical rigor, and the ability to move quickly between test operations, data interpretation, and hardware problem-solving. You will play a critical role in increasing engine development velocity and reliability.

Own development engine test campaigns from planning through execution and post-test analysis

Define, author, and refine engine test plans, procedures, and setpoints aligned with program objectives

Support and make decisions during live test operations, including hot-fire and subsystem testing

Identify, diagnose, and resolve test-related engine issues across hardware, instrumentation, and procedures

Standardize and improve test data review, reduction, and reporting processes

Develop Python-based tools for data processing, visualization, and automated analysis

Translate test data into clear engineering insights, including performance characterization and root cause analysis

Drive post-test reviews and ensure actionable outcomes are captured and executed

Participate in hands-on engine build, integration, and test setup activities

Author and maintain development engine work instructions, test procedures, and technical documentation

Generate, track, and resolve engineering issues through ticketing systems

Collaborate cross-functionally with design, manufacturing, avionics, and test teams to resolve system-level challenges

Ensure proper sensor selection, instrumentation setup, and data integrity during test campaigns

Contribute to continuous improvement of test infrastructure, tooling, and development processes

Bachelor’s degree in Mechanical Engineering, Aerospace Engineering, or a related discipline

Hands-on experience with hardware build, integration, or test operations

Experience developing or executing engineering test plans and procedures

Proficiency in Python for data analysis and automation

Strong understanding of sensors, instrumentation, and diagnostic techniques

Experience with liquid rocket engines or air-breathing propulsion systems

Familiarity with high-speed data acquisition and telemetry systems

Background in thermofluids, combustion, or turbomachinery

Experience operating in fast-paced, iterative hardware development environments

Demonstrated ownership of hardware or test systems through multiple development cycles

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