Being developed by Bye Aerospace, Sun Flyer 2 is a twin-seat, all-electric aircraft intended for pilot training missions. The aircraft is offered in two variants namely Sun Flyer 2 and Sun Flyer 4, which is a four-seat version.

The prototype of Sun Flyer 2 aircraft completed its maiden flight at Centennial Airport (KAPA), located south of Denver, Colorado, US, in April 2018. The aircraft’s flight characteristics such as speed, altitude and endurance were assessed during the flight test.

The aircraft is expected to receive the Federal Aviation Administration (FAA) certification in the second half of 2018.

Orders and deliveries

Spartan College of Aeronautics and Technology placed an order for 20 Sun Flyer 2 aircraft in 2016. Bye Aerospace received deposits for 105 Sun Flyer 2 aircraft from unidentified customers as of April 2017.

Sun Flyer 2 aircraft design and features

The Sun Flyer 2 incorporates a cantilever low-wing design. The fuselage, made of composite materials, is fitted with a fixed tricycle landing gear.

“The operating cost of the Sun Flyer 2 is $14 an hour, which is much less compared to Cessna 172’s $88.31 an hour.”

The aircraft offers longer operating life and is also integrated with a ballistic parachute recovery system.

The two-seater variant has a wingspan of 11.58m, wing area of 129ft² (12m²), cabin width of 1.16m and glide ratio of 18.5. It has an empty weight of 1,460lb (662 kg), while the gross weight of the aircraft is 1,900lb (862kg).

The operating cost of the Sun Flyer 2 is $14 an hour, which is much less compared to Cessna 172’s $88.31 an hour.

Cockpit and avionics

The aircraft features an open cockpit enclosed by a bubble canopy. The on-board avionics suite is provided by Avidyne Corporation. The easy-to-fly aircraft is installed with a next-generation customised instrument panel.

An iPad is installed in the cockpit to display the characteristics of motor, battery and aircraft systems. The Sidekick system tracks the engine, flight time, physical location and attitude of the aircraft.

The real-time information of the engine, flight time, location and attitude of the aircraft can be tracked by the Sidekick system supplied by Redbird Flight Simulations.

Engine and performance of the all-electric training aircraft

The FAR 23-certified Sun Flyer 2 is equipped with an electric propulsion system powered by six lithium-ion batteries. The motor, which drives a two-blade composite propeller, develops a maximum power of 110hp (80kW).

The control unit on-board the aircraft enables the optimal use of energy stored in the batteries to control the engine performance.

The maximum rate of climb of the aircraft is 1,150fpm, while the normal speed varies between 55kt and 120kt. The aircraft has a flight endurance of 3.5 hours.

EP Systems supplied the energy storage system, battery modules, power distribution unit and battery management unit for the prototype aircraft.

Sun Flyer 4 variant details

The operating cost of the four-seat Sun Flyer 4 is $19.80 an hour, compared to Cessna 182’s $122 an hour.

The variant has a wingspan of 38ft (11.58m), wing area of 129ft² (12m²) and gross weight of 2,700lb. It has a cabin width of 46in (1.16m) and a glide ratio of 18.7. The aircraft is powered by an electric propulsion system with a rated power of 105kW.

The maximum rate of climb of the variant is 1,250fpm, while the normal speed is between 55kt and 120kt. The flight endurance is four hours.