Director of Mechanical Engineering

About Mainspring

Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more. The core values that ground our work, guide our decisions, and connect us together: Pragmatic Optimism Excellence without Ego Proactive Collaboration

Director of Mechanical Engineering

We are seeking a Director of Mechanical Engineering to lead a substantial portion of the team scaling the Linear Generator — a first-of-kind distributed power platform that converts a low-temperature, flameless reaction directly into electricity using high-frequency linear motion instead of rotating machinery. The system integrates reciprocating pressure-driven assemblies, air-spring return chambers, precision alignment systems, and linear electromagnetic machines within a modular 250 kW-class packaged unit. It operates under cyclic loads, tight sealing constraints, thermal gradients, structural dynamics, and grid-interactive performance requirements typical of commercial power generation equipment. Reporting to the VP of Mechanical Engineering, this role is being created to expand leadership capacity, elevate risk visibility, and enable disciplined scaling of a growing hardware portfolio. You will own ~40–50% of the mechanical organization’s active projects and lead ~25 direct and indirect reports, with scope expected to grow. Your teams will oversee multiple core subsystems that are tightly coupled and reliability-critical. Success requires both deep mechanical intuition and strong organizational leadership. You will strengthen technical rigor, improve prioritization across 50+ active efforts, and build execution systems that allow the organization to scale without sacrificing engineering excellence.