Mechanica Engineer - Composite Structure

About this role

ABOUT US Harmattan AI is a next-generation defense prime building autonomous and scalable defense systems. Following the close of a $200M Series B, valuing the company at $1.4 billion, we are expanding our teams and capabilities to deliver mission-critical systems to allied forces. Our work is guided by clear values: building technologies with real-world impact, pursuing excellence in everything we do, setting ambitious goals, and taking on the hardest technical challenges. We operate in a demanding environment where rigor, ownership, and execution are expected. ABOUT THE ROLE As a Senior Mechanical Engineer – Composite structure on Harmattan AI's Airframe team, you will design UAV structural assemblies in an autonomous, fast-paced environment, with a strong emphasis on composite (carbon) structures alongside injection-moulded and CNC parts. You will take ownership of projects from concept through to production, ensuring the right balance of rigidity, mass, cost and manufacturability, and you will drive fast in-house carbon prototyping as carbon structures become central to our larger platforms (VTOL 2, flying wings). TECHNICAL SKILLS RESPONSIBILITIES - Design and prototype UAV composite structures and complex subsystems from scratch, ensuring the right balance between durability, efficiency, and performance. - Own the composite structural design (~40 % of the role): material selection, laminate and ply orientation, monolithic vs sandwich trade-offs, bonded and bolted joints, inserts and hard points for load introduction — from concept through to production. - Design injection-moulded and CNC parts (~50 % of the role) and their integration with the composite structure, applying design-for-manufacturing rules (wall thickness, draft angles, tolerances) from the first concept. - Take full ownership of system-level constraints, including thermal management, mass budget (weight), COGS (cost), and environmental sealing (IP ratings). - Define the tooling and process strategy for composite parts — moulds, layup, vacuum bagging, infusion or prepreg, co-curing — favouring fast in-house carbon prototyping at early stages over heavy tooling, then converging towards series processes. - Conduct rigorous testing, including stress and failure analysis (laminate strength, delamination, inserts pull-out); develop the necessary tools (test benches, coupon campaigns, calculation sheets, or scripts) to validate designs for operation in extreme environments. - Work closely with R&D teams (Electrical, Software, and Industrialisation) to ensure seamless mechanical integration of sensors, payloads, and electronics. - Oversee the manufacturing process by collaborating directly with suppliers and external manufacturers, with a focus on composite fabrication, plastic injection moulding and precision machining, to ensure quality and schedule targets are achieved. - Maintain the "source of truth" through Confluence and professional 2D/3D documentation, including ply books and cure/process logs. Document all designs, test results, and production workflows to support knowledge sharing and continuous improvement. - Act as a technical reference on composites: mentor junior engineers, review designs, and help establish the team's composite methods and standards. CANDIDATE REQUIREMENTS - Master's degree in Mechanical Engineering, Aerospace Engineering, or a related field. - Proven experience designing and prototyping mechanical systems, ideally within UAVs, robotics, or defence applications. - Solid knowledge of composite materials and carbon structure design: laminate design and ply orientation, anisotropy, knockdown factors, damage / delamination criteria, bonded joints and metallic inserts / hard points for load introduction. - Hands-on experience with composite fabrication and tooling — layup, vacuum bagging, infusion and/or prepreg, mould design — with a track record of rapid in-house carbon prototyping (speed of iteration over perfect tooling at early stages). - Proficiency in CAD software (e.g., SolidWorks); experience with structural and thermal analysis tools (FEA) is a strong advantage — laminate / composite analysis capability is a plus. - Strong understanding of manufacturing processes, including plastic injection moulding, high-precision machining, and series composite processes (infusion, prepreg / OOA, RTM), with the ability to design to a target cost and production rate. - Excellent written and verbal communication skills, with the ability to clearly document complex technical concepts and lead cross-functional discussions. - Full commitment to Harmattan AI's mission, vision, and growth plans, with a willingness to go the extra mile in pursuit of operational excellence. We look forward to hearing how you can help shape the future of autonomous defense systems at Harmattan AI.