Development of “Aria,” a Compact, Quiet Personal Electric Helicopter

This paper describes the development and flight testing of a personal air vehicle by team Harmony for the GoFly Prize competition. The competition emphasized an open‐air flight experience, and the final aircraft was scored by size (≤8.5 ft), noise (<87 dBA), and speed (>30 kt). The highest scoring team would win a $1 million grand prize. Team Harmony endeavored to develop an aircraft which would maximize the competition score. A counterrotating coaxial electric helicopter configuration was chosen to maximize rotor area and reduce disk loading for efficiency and acoustic benefits. The rotors were designed through a parametric study using an in‐house aerodynamics code, an in‐house acoustics code, and CREATE™‐AV Helios CFD. A quiet electric power train and custom 11 kWh battery were developed. Flight control was implemented with dual, independent, electronically coupled swashplates. A one‐third‐scale prototype aircraft was first developed and flight‐tested. Then a full‐scale, 520 lb (235.4 kg) prototype with an 8.45 ft (2.58 m) rotor diameter was developed and flight‐tested. During hovering, the measured sound pressure levels at 50 ft (15.24 m) were 73 dBA. The full‐scale vehicle crashed before its speed capabilities could be tested, but the aircraft would have likely scored well, achieving the goal of the project. This work encompassed several design trade‐offs, especially between aerodynamic and acoustic performance in the rotor and blade design, and between acoustics and endurance in the power source selection, and in availability and flight‐worthiness of off‐the‐shelf hardware for personal flight.