Uncrewed Systems Technology 049 - April/May 2023

82 W e last featured Rotron Power in UST 4 (Autumn 2015), its RT600 twin-rotor Wankel gasoline engine having enjoyed significant commercial success, in both of the versions that were then available. One of those was the RT600-LCR (for ‘liquid- cooled rotor’) which thermally managed its rotor via charge cooling, the other was the RT600-XE (for ‘exhaust ejector’) which used a vacuum ejector system to pull air through the engine for cooling the rotor. Both also used liquid cooling for thermal management of their housing and eccentric shaft. Since then, the company has continued to evolve its engine designs, and reshaped its engine production line and commercial approach in response to the changing landscape of the UAV industry. For example, it has discontinued the LCR and replaced it with the RT600- HC (for ‘helicopter’) rotorcraft unit. The RT600-XE is still available, principally for non-helicopter UAVs and small Rory Jackson looks at the development of this Wankel engine designed for rotorcraft vehicles Spin master April/May 2023 | Uncrewed Systems Technology The RT600-HC is a 600 cc Wankel based on the famed Fichtel & Sachs KM914’s design (Images courtesy of Rotron Power)