The fuel cell hybrid drive train was integrated into the Hy4 for the upcoming MAHEPA ground and flight test phase.
The fuel cell system, the PMCD and the drive unit were installed on the middle wing, in a central nacelle, between the two fuselages. In the fuselages the battery and tanks are located in separated areas. The control software functions in MAHEPA have been thoroughly improved and implemented in the controllers and the main flight computer. With the new firmware, optimized safety functions and system reliability was achieved.
A challenging point was the integration of the fuel cell cooling system and the complete aerodynamic housing. The fuel cell cooling was integrated on the middle wing in a way that clearly improved the cooling performance compared to the first generation of Hy4 cooling system. An optimized air flow was achieved by developing new air duct housings and an aerodynamic housing for the central nacelle.