The 3507 Engine by Hirth Engines is a water-cooled, two-cylinder inline two-stroke heavy fuel engine designed to deliver reliable performance and a high power-to-weight ratio for demanding unmanned and industrial applications.
Featuring reed valve control and advanced air-assisted direct injection, the engine is engineered to provide consistent power output and efficient operation across a range of challenging environments. The liquid-cooled design supports extended operational range in challenging conditions, while compatibility with kerosene-based fuels such as JET-A1 and JP-8 simplifies logistics for military and expeditionary platforms.
The heavy fuel engine delivers 57 HP (42.38 kW) of measured power at 6500 RPM. Fully NATO-compliant, the 3507 Engine is designed for versatility across maritime, defense, and industrial platforms, including Unmanned Aerial Vehicles (UAVs), Unmanned Surface Vehicles (USVs), expeditionary and military platforms, civilian machinery, and heavy-lift unmanned aircraft.
Integration options include the G 50 gearbox with multiple reduction ratios (1:2.16, 1:2.29, 1:2.59, 1:3.16, and 1:3.65), an integrated 1–3 kW / 28 V starter-generator, electronic throttle control via an integrated servo, and heavy fuel capability.
The engine measures 481 mm in length, 453 mm in width, and 443 mm in height, and weighs 33.5 kg without exhaust. Designed for durability and reliability, it offers a time between overhauls (TBO) of 500 hours.
