Mechanical Engineer

SiFly; San Francisco (CA); On-site; USD 180,000 - 230,000; Full time

Job summary

SiFly is hiring a Staff Mechanical Engineer to lead the mechanical design of our next-generation autonomous UAV products. This hands-on role involves prototyping in-house, guiding changes through field flight tests, and driving manufacturing as we scale production in our Santa Clara factory.

You will own mechanical assemblies from concept to installation on flying units, balance performance against weight, and collaborate closely with Electrical, Software, Integration, Test, Manufacturing,

Qualifications

• Solid background in mechanical systems (structural mechanics, heat transfer, fluid dynamics).
• Experience designing composite, injection-molded, and machined parts for production.
• DFMEA, tolerance analysis, life testing, HALT and related design discipline.
• First-principles thinking and propulsion/power/radio technology understanding.
• Hands-on work with flying units and data-driven design decisions.
• Proficient in parametric CAD with Fusion 360 familiarity.

Responsibilities

• Own the design of mechanical assemblies from concept to flight-ready units.
• Design and improve drone subsystems balancing performance and weight.
• Lead field flight testing and iterate from flight data.
• Design for manufacturability across composites, injection molding, and machined parts.
• Produce detailed drawings for fabrication and fixtures.
• Manage mass budgets and tolerance analyses; define interfaces.
• Collaborate with Electrical, Software, Integration, Test, Manufacturing, Operations, and Supply Chain teams.
• Explore AI-assisted design workflows and share learnings.

Skills

Composite parts design

Injection-molded parts

DFMEA

First-principles engineering

AI-assisted design workflows

Parametric CAD

Design for manufacturing

Tools

Fusion 360

SolidWorks

Job description

At SiFly, we're building a new category of aircraft: vertical-takeoff, long-endurance drones that deliver helicopter-level performance at drone economics. After thousands of flight tests and years of engineering, our NDAA-compliant platform flies more than 2 hours in hover or 3 hours in forward flight on a single charge - matching the capability of traditional helicopters at a fraction of their cost and operational burden. We merge aerial robotics, perception, and onboard intelligence to cut complexity and minimize human intervention, and our unique approach to communications and networking unlocks remote operations from day one. It's an ambitious mission, and we're a small team that moves fast.

About the Role

We're hiring a Staff Mechanical Engineer to lead the mechanical design of one of our next-generation autonomous UAV products. This is a hands-on lead role: you'll prototype and design in-house, guide changes through field flight testing, and drive the product into manufacturing as we scale production in our Santa Clara factory. Direct UAV experience is a strong plus, but we'll seriously consider the right background paired with genuine curiosity and a drive to learn.

Responsibilities

• Own the design of mechanical assemblies and systems for our aircraft - from concept exploration to installation on flying units.
• Design and improve drone subsystems and highly integrated electromechanical assemblies, balancing performance against weight.
• Guide designs through field flight testing, and use real flight data to drive design changes and back your recommendations.
• Take products beyond the prototype into medium-volume production, designing for manufacturability across composite, injection-molded, and machined parts.
• Produce detailed engineering drawings for fabrication and assembly, and design fixtures for assembly and test.
• Own mass budgets, tolerance analysis, and the interface definitions between your parts and everyone else's.
• Collaborate closely with the Electrical, Software, Integration, Test, Manufacturing, Operations, and Supply Chain teams at every stage.
• Find, build, and share AI-assisted approaches to mechanical work - design exploration, analysis setup, drawing and documentation review - and bring the rest of the team along with what works.

Qualifications

A solid background in mechanical systems, including structural mechanics, heat transfer, and fluid dynamics.

Required Skills

• Experience designing composite, injection-molded plastic, and machined parts - particularly taking products from prototype into medium-volume production.
• Familiarity across manufacturing technologies: additive, subtractive, vacuum forming, injection molding, and more.
• You anticipate failure systematically. You've worked somewhere that did this properly - DFMEA, design margin and derating, fatigue and life testing, tolerance-stack risk, accelerated life and HALT - and you can bring that discipline to a team that hasn't had it. Not process for its own sake: it's cheaper to find a failure on a bench than in a customer's hands.
• First-principles thinking and a drive to understand the "why" behind traditional approaches to propulsion, power systems, and even radio technologies.
• This is a hands-on job at a company that is still small. You'll be at the bench, in the shop, on the flight line, and sometimes at a customer site working out why a deployed system is misbehaving - alongside new product development, not instead of it.
• You use AI as a real tool, not a talking point. We want to hear one specific example of something you did with AI that surprised you - a workflow you rebuilt, a problem you came at sideways, an analysis that wouldn't have been worth doing by hand. We care less about which tools you use than about what you've changed about how you work. We're enthusiastic about the leverage and unforgiving about errors.
• Strong parametric CAD. We work in Fusion 360 and are standardizing on it - if you're coming from SolidWorks or another package, that's fine. We care that you're fluent and willing to make the switch.
• A desire to test changes on real flying units and make recommendations grounded in flight data.

Preferred Skills

• Aerospace, consumer, or automotive hardware experience.
• Carbon fiber composite and aerodynamic structures, and an understanding of design for weight.
• Robotics and highly integrated electromechanical assemblies under system-level constraints.

Pay range and compensation package

Details Onsite in Santa Clara, CA. Small team, high ownership, and a lot of hands-on prototyping in our shop.

Equal Opportunity Statement

We are committed to diversity and inclusivity.