Due to 100% gaseous emission reduction, the focus was on configurations supporting liquid hydrogen propulsion system.
Four potential candidates were selected for conceptual design loops procedure. Candidates' main features were variable incidence wing, drag optimized airframe, tail cone propeller and control-type canard, cantilever wing, distributed electric propulsion on the wing, tail cone propeller, high-aspect ratio wing, tail cone ducted fan...
Candidates were compared on the basis of manufactural complexity level, success index and (noise) emission index. A combination of candidates was chosen (C7A-HARW), featuring high aspect-ratio wing and tail cone propeller.
Higher fidelity analyses were performed to define the building blocks of the subsystems in more detail and to verify technical assumptions made within design loops.
Mid-fidelity panel methods used in sizing loops were validated against CFD and wind tunnel test results, allowing build up a realistic aerodynamic model of the entire aircraft.
Structural FEM design indicated a potentially lighter wing design due to DEP installation, with critical flutter speed indicated well above selected cruise speed of the aircraft.
Tank gravimetric index and power density of the fuel stack were estimated. The difference between values used in sizing loops and from detailed design were below 5%.
The power delivery system was designed with 2-sub-systems redundant architecture, increasing redundancy in case of building blocks failures.
A non-linear, 6-DOF, flight dynamics simulator was built in Simulink, and flight control laws were developed to handle activity of DEP propellers, pusher propeller and control surfaces in normal operation and emergency conditions.
A comprehensive safety analysis indicated high redundancy in propulsion units, power supply system and their independence on architecture.
Noise emission analysis was focused on the departure procedure. It showed 10dB - 20dB reduction with respect to classical twin turboprop aircraft, optimized for UNIFIER19 mission.
Production and operating cost analysis indicated 22% higher purchase price for C7A-HARW that for classical twin turboprop aircraft, however, direct operating cost analysis yielded 10% lower cost-per-available-seat-kilometer for C7A-HARW than twin turboprop aircraft.
