Hirth Engines

Hirth Engines is an industry-leading developer of advanced two-stroke engines for UAVs (unmanned aerial vehicles). With over 90 years of aviation experience and 30 years serving the drone industry, we are committed to providing our customers with the perfect fit for their propulsion needs, and to remaining at the forefront of engine technology.

Our products have been incorporated into a wide variety of UAV platforms all around the world, including:

• V-200 (UMS Skeldar)
• V-BAT 118 (Shield AI)
• BAT12 (Northrop Grumman)
• Luna (Rheinmetall)
• AWHERO 150 (Leonardo)

Learn more: Hirth UAV Engines

Cutting-edge two-stroke engine technology for UAVs

Our state-of-the-art two-stroke engines offer excellent power-to-weight ratios and low fuel consumption, making them ideal for the needs of unmanned aviation.

Our products are developed by a team of highly experienced experts at our research and technology facility near Stuttgart, Germany, and every single component, whether manufactured in-house or by our vendor partners, is subject to rigorous testing.

We have developed a custom electronic direct injection system that provides unparalleled fuel consumption and smooth-running characteristics, as well as a range of other benefits for UAV platforms, including:

• Fuel quantity is optimized according to altitude and climate conditions
• Fuel-air mixture can be fine-tuned to meet specific requirements
• Lean mixture settings reduce CO2 emissions
• Improved cold start and hot start mixture formation
• Reduction of smoking during start and warm-up phase
• Automatic speed limitation by interruption of fuel injection, meaning no misfiring
• Customized engine management systems can be easily integrated into existing UAV control & communications buses

We offer options for gasoline as well as heavy fuel engines for UAVs, providing solutions for commercial, military and maritime applications alike. All base engines can be customized and adapted to create bespoke solutions that meet your unique UAV propulsion requirements.

Two-stroke engines for UAVs

23 Series

The air-cooled 23 Series is ideal for UAVs weighing up to 120 kg, delivering 50 HP with an unmatched power-to-weight ratio. Engineered to provide superior reliability, it offers a 1000-hour TBO and can be equipped with a range of options including dual ignition, fuel injection, and an electric starter.

35 Series

With liquid cooling and exceptional durability, the 3503 offers the maximum possible power-to-weight ratio available on the 70-horsepower market. It can be optionally equipped with dual ignition, an electric starter, and separate lubrication system.

A heavy-fuel variant, the 3507, is available to suit the requirements of maritime applications and defense forces.

41 Series

Based on a proven design that has flown over 20,000 real-world missions in the most demanding environments, the air-cooled 41 Series offers the latest in two-stroke UAV engine technology. Utilizing advanced closed-loop control and automatic altitude and temperature compensation, it delivers up to 8.1 HP at 6700 rpm and ensures ultra-reliable performance under extreme environmental conditions.

42 Series

Like the 41 Series, the air-cooled 42 Series incorporates advanced closed-loop control and automatic altitude and temperature compensation for optimal performance under any conditions. Delivering up to 15HP at 6500 rpm, it can be equipped with oil injection, various reduction drive options, and starter/generator capabilities of up to 1 kW.

A heavy-fuel variant, the 4202, is available to suit the requirements of maritime applications and defense forces.