Hirth Engines and ePropelled announced a strategic collaboration to develop hybrid propulsion solutions targeting the UAV, aerospace, and defence markets. The partnership combines Hirth’s decades-long expertise in two-stroke engine technology with ePropelled’s intelligent electric propulsion and power-management systems.
Technical Specifications of Hybrid Propulsion Integration
The hybrid propulsion systems will integrate Hirth’s high-performance two-stroke engines with ePropelled’s starter-generators and electronic engine starters. This approach merges mechanical power generation with advanced electric systems, addressing demand for lightweight, energy-efficient propulsion in demanding applications.
Hirth is bringing their 3508HF to the table, a variant within the Hirth 35 series of liquid-cooled, two-cylinder, in-line two-stroke engines designed for UAVs and light aircraft. The 3508HF features heavy fuel capability, providing operational flexibility for military and commercial UAV applications where jet fuel compatibility is required.
According to the companies, the hybrid propulsion solutions will deliver significant fuel-efficiency gains, extended flight duration and payload capacity, and lower lifecycle operating costs. The systems are designed to provide enhanced reliability and redundancy for mission-critical applications while improving sustainability to meet emerging regulatory standards.
The partnership emphasizes superior power-to-weight ratios and dependable performance, critical specifications for UAV operations in challenging environments. Bruno-Gerard König, CEO of Hirth Engines, stated: “This partnership elevates what our engines can achieve and opens new opportunities in fast-growing sectors such as UAVs and advanced air mobility. ePropelled’s technology perfectly complements Hirth’s heritage of engineering excellence.”
UAV Applications and Development Timeline
The collaboration targets multiple applications including UAVs and uncrewed systems, advanced air mobility platforms, defence and surveillance missions, and industrial aerial applications. Nick Grewal, CEO & Founder of ePropelled, commented: “Combining our intelligent electric power-generation systems with Hirth’s world-class engines allows us to deliver hybrid solutions that set a new benchmark for performance and efficiency. This collaboration accelerates the future of hybrid propulsion.”
Research, development, and system-integration work are underway, with prototype demonstrations expected in upcoming project cycles. The companies plan to showcase prototypes at UMEX in Abu Dhabi in January 2026, providing industry stakeholders with opportunities to evaluate the hybrid propulsion technology firsthand.
Hirth Engines, based near Stuttgart, Germany, has nearly 100 years of experience manufacturing two-stroke engines for aviation and UAVs. ePropelled, founded in 2018 and headquartered in Laconia, New Hampshire, holds 40 patents in smart propulsion and energy-management systems for uncrewed vehicles.
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Ian McNabb is a journalist focusing on drone technology and lifestyle content at Dronelife. He is based between Boston and NH and, when not writing, enjoys hiking and Boston area sports.
