Director of Mechanical Engineering
Mainspring Energy· startup· Energy· Feb 24, 2026 · 8mo agoPosted 245 days ago
Menlo Park, CA
In office
Full-time
Director
$237K–$267K
18+ years exp
Before you apply
Ghost Signal:
Open since February 24, 2026 — 245 days, and still accepting applications.
Job description
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
This is not a pure people-management role. We are looking for a hands-on mechanical engineering leader who has built real hardware, moved fast in imperfect environments, and developed the judgment to recognize technical risk before it becomes a field or manufacturing problem. You should be comfortable leading managers and senior engineers, but also capable of diving into a design review, asking the question that changes the direction of a project, and helping the team make a high-quality decision under uncertainty.
The ideal candidate has experience in a startup or high-growth hardware environment where process was incomplete, ownership was still being defined, and the product had to mature while the company was scaling. You may have helped take a product from early development into production, or you may have led major subsystems through repeated design, test, manufacturing, reliability, and field-learning cycles. You know that process matters, but you also know how to build just enough process to improve execution without slowing down creative engineering.
Reporting to the VP of Mechanical Engineering, you will lead multiple subsystem-focused teams, develop managers and technical leaders, raise the technical bar, and help the organization scale from heroic execution toward disciplined, repeatable product development.
Core Responsibilities
Lead multiple mechanical engineering teams responsible for delivering high-quality subsystem designs from concept through manufacturing. Own a significant portion of the mechanical engineering project portfolio. Develop and lead managers/technical leads in the execution of these projects.
Be accountable for technical oversight, roadmap planning, engineering process discipline, and team development across your scope. Serve as a key escalation point for technical issues, project risk, and cross-team dependencies; remove blockers and ensure rapid, high-quality decisions.
Strengthen day-to-day engineering execution systems (e.g., project tracking hygiene, communication discipline, timely review/approval flows) so teams can scale without losing rigor.
Partner closely with Supply Chain, Supplier Quality, and Manufacturing teams to support sourcing decisions, supplier technical engagement, and fast resolution of technical issues in manufacturing.
Partner closely with Field, O&M, Test and Reliability teams to support issue triage, structured problem solving, and prevention of recurrence.
Qualifications
BS or higher in Mechanical Engineering or a related engineering field.
18+ years of progressive mechanical engineering experience delivering complex hardware products, ideally in industrial equipment, energy systems, automotive, aerospace, robotics, climate tech, manufacturing equipment, or similarly demanding environments.
Experience leading mechanical engineers and/or engineering managers. We care more about demonstrated leadership quality, technical judgment, and ability to scale teams than exact org size.
Strong mechanical engineering fundamentals and practical design intuition developed through real design, test, manufacturing, reliability, or field experience.
Demonstrated ability to identify failure modes and technical risks in incomplete designs, early concepts, manufacturing issues, or field problems.
Experience operating in a startup, scale-up, new product introduction, or high-growth hardware environment where the path was not fully defined and process had to be built or improved.
Track record of helping a product, subsystem, or engineering organization mature: from early concept to production, low volume to higher volume, prototype to reliable fielded product, or chaotic execution to repeatable execution.
Ability to lead across many parallel projects while staying connected to the technical details that matter most.
Experience building or improving engineering systems such as requirements, design reviews, risk reviews, validation plans, release/change control, documentation practices, project tracking, or technical decision-making forums.
Strong people leadership: develops managers and senior engineers, creates clear ownership, gives direct feedback, builds accountability, and creates a supportive environment where people grow.
Comfortable being both strategic and hands-on. You can set direction for the organization, but you are also willing to go deep when the product or team needs it.
Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.
In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.
This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.
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