Unmanned Systems Technology 025 | iXblue DriX I Maintenance I UGVs I IDEX 2019 I Planck Aero Shearwater I Sky Power hybrid system I Delph Dynamics RH4 I GCSs I StreetDrone Twizy I Oceanology Americas 2019

60 S ky Power has developed a flexible hybrid solution for UAV powertrains that combines fuel and electrical power. “One of the driving concepts for us, when developing our [Wankel-type] rotary and two-stroke power units, is that we feel the future of the UAV market is focused on more electricity,” says Walter Seidl, the company’s chief engineer. Sky Power’s managing director Karsten Schudt adds, “All our engine concepts will be able to incorporate this hybrid system, whether the engine is a two-stroke or a rotary.” The internal combustion engine is the core of Sky Power’s hybrid platform, with the cooling system being closely tied to the engine type. For a two-stroke, an air- cooling system will typically be integrated. For a rotary, the company integrates its thermal management system, which combines oil and water cooling, with the water system serving the rotor housing extended to cool the hybrid’s 48 V motor/ generator unit (MGU). Regardless of type, the engine is run by the company’s own ECU, with a CAN bus comms architecture running throughout the power unit. CAN enables the use of a single protocol, not only for the comms but also for the control systems, and for interfacing with Sky Power’s in-house calibration tool, UniCal. “This protocol is also used across our different engine types, with the flight controller possibly also transmitting and receiving signals via CAN,” Seidl adds. “There are certain differences between Rory Jackson examines this hybrid system, which can be incorporated into different types of UAV engine Fit for purpose The SP-180 SRE hybrid Wankel engine is Sky Power’s first propulsion system launched with the hybrid platform, with three of the company’s two-stroke engines also having been subsequently upgraded, tested and made available with this hybridisation approach April/May 2019 | Unmanned Systems Technology