Two-Stroke vs Wankel Engines for UAVs: Which Propulsion Technology is Most Suitable for the Respective Mission Profile?

The choice of propulsion system in the development of unmanned aerial systems is far more than a matter of design detail. For technical decision-makers, it directly influences flight duration, payload capacity, integration capabilities within the platform, reliability in the field, maintenance requirements, and long-term operating costs. Especially for UAVs designed for tactical operations, long-range missions, or sensor-based reconnaissance tasks, the engine is an essential system component rather than an exchangeable standard part. In the field of UAV propulsion systems with internal combustion engines, the focus is on the classic two-stroke engine and the Wankel engine. Both technologies have their validity, both offer clear advantages in UAV applications, and both also come with technical limitations. The central question is therefore not which concept is fundamentally superior. The decisive factor is rather which engine concept delivers the better system response under the respective operating conditions. This is precisely where the actual technical evaluation begins.