Director of Mechanical Engineering

Company Overview

Mainspring Energy is revolutionizing power generation with the world’s most flexible and adaptable local power generation technology, the Mainspring Linear Generator. Commercial, industrial, and utility leaders are choosing Mainspring over traditional options like engines, turbines, and fuel cells to quickly and reliably deliver local power for EV charging, commercial facilities, data centers, and grid-scale operations. The Mainspring Linear Generator is fuel flexible, ramps up and down to meet demand, and utilizes a flameless reaction with near-zero NOx emissions.

Backed by top-tier investors including Khosla Ventures, Bill Gates, American Electric Power, Lightrock, and General Catalyst, Mainspring designs, manufactures and delivers its products to customers across the U.S. today, and we’re quickly scaling for international expansion.

Inspired by our vision of the affordable, reliable, net‑zero carbon grid, Mainspring is rapidly expanding within the $816B global electricity equipment market, and we’re hiring the best talent to meet growing customer demand around the globe. We welcome a broad range of backgrounds, experiences, and talents to bring fresh perspectives and ongoing innovation to our customers.

We are looking to build relationships with people who share our values:

Pragmatic Optimism. Building a new category of world‑class power generation requires the optimism of ambition and creativity, balanced with practicality to solve problems efficiently. The challenges that arise are opportunities for growth.

Excellence without Ego. We bring expertise and commitment to creating the best customer experience, from sales to deployment and service, just as we apply deep technical rigor to building and delivering world‑class products. We strive for excellence and behave as leaders with the humility to acknowledge our challenges, both collectively and as individual contributors.

Proactive Collaboration. The integration and cross‑disciplinary nature of Mainspring’s business requires intentionally seeking out others who bring different skills, perspectives, and priorities. Our culture of inclusion and respect extends beyond our team to interactions with our partners and customers.

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.

• Leadership of ~25 engineers (direct and indirect), including managers
• 40–50% of the mechanical project portfolio
• Accountability for multiple core subsystems
• Early identification and mitigation of subsystem and program‑level risks
• Strong engineering review discipline (FMEA, DVP&R, tolerance analysis, ECO governance)
• Partnership with Manufacturing and Supplier Quality to support at‑scale production
• Development of future engineering leaders

• 18+ years delivering…