The 4201 Engine by Hirth Engines is a lightweight two-stroke boxer engine developed for light aviation and Unmanned Aerial Vehicle (UAV) applications, combining reliable performance with a strong power-to-weight ratio for endurance-focused operations.
As part of the updated 42 Series, the engine features advanced closed-loop control technology designed to optimize performance in challenging environmental conditions. Automatic altitude and temperature compensation support consistent operation across varying operating environments.
With a measured output of 13.6 HP at 6500 RPM and a weight of 7.14 kg excluding the exhaust, the 4201 Engine is suited to UAV platforms requiring lightweight propulsion systems.
Powered by petrol fuel, the engine features a single ignition system, starter generator, and counterclockwise running direction. The engine incorporates a 54 mm bore and 40 mm stroke within dimensions measuring 214.5 mm in length, 339.8 mm in width, and 239.7 mm in height, while the standard exhaust configuration weighs 1.15 kg.
The 4201 Engine also supports a range of configurable options, including two exhaust styles, oil injection, and starter/generator outputs of up to 1000 W. Additional customization is available for elements including quality documentation, design, and rotational direction.
The engine delivers measured torque figures of 14.9 Nm at full throttle and 15.5 Nm at its best operating point, while specific fuel consumption is rated at 482.83 g/kWh at 6500 RPM and 434.79 g/kWh at its best operating point under 70-80% load conditions.
Find out more about the 4201 Engine and the wider 42 Series from Hirth Engines here >>
