Bye Aerospace eFlyer 2

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eFlyer 2
Role Electric training aircraft
National origin United States
Manufacturer Bye Aerospace
First flight 10 April 2018
Status Under development (since 2016)
Number built 1
Variants Bye Aerospace Sun Flyer 4

The Bye Aerospace eFlyer 2 (formerly the Sun Flyer 2)[1] is a light electric aircraft designed and under development by Bye Aerospace of Denver, Colorado.

The aircraft was first publicly introduced on 11 May 2016, and first flew on 10 April 2018.

The two seater is designed for the flight training market with a single tractor electric motor powered by Lithium-ion batteries.


The design was originally developed by Bye Aerospace subsidiary Aero Electric Aircraft Corporation (AEAC).[2][3] Arion Aircraft of Shelbyville, Tennessee constructed the proof-of-concept prototype[4] and delivered it in March 2016.[5]

The eFlyer 2 was first publicly introduced at the Centennial Airport in Colorado on 11 May 2016.[3] Ground and taxi tests on the prototype were started in November 2016.[6] A four-seater derivative model, named the Bye Aerospace Sun Flyer 4, was announced in July 2017. It will be a day/night IFR aircraft with an 800 lb (360 kg) payload, capable of 150 kn (280 km/h) maximum cruise speed and a 4.2 hour endurance.[7][8]

The eFlyer 2 first flew on 10 April 2018.[9][10] AEAC and Bye Aerospace merged in 2018 and Bye Aerospace took over the project.[11]

Development of the four-seater should follow completion of the smaller eFlyer 2, the certification of which is forecast to cost US$25 million. Bye had received 220 orders for the two models by October 2018.[12] By January 2019, Subaru and SBI Investment invested in Bye Aerospace to advance the eFlyer 2 certification.[13] On 8 February 2019 the eFlyer 2 flew for the first time in its intended production configuration, including with a Siemens SP70D electric motor.[14]

FAA Part 23 Certification was planned for 2020,[15] with Siemens taking an active part.[16]

In November 2020 it was announced that the motor supplier would instead be Safran.[17] In an email to AOPA, George Bye indicated the reason for the change, that Bye Aerospace was “… unable to reach a mutual commercial proposition…” with Siemens/Rolls Royce.[18]

At AirVenture in July 2021 George Bye of Bye Aerospace stated that the eFlyer 2 will be certified in late 2022 or early 2023 with a target price of US$489,000.[19]


The aircraft is intended to be certified under FAR 23 and supplied as a complete ready-to-fly-aircraft.[20][2] It has been designed specifically for the flight training market and is projected to have a 3.5 hour duration.[2][3] The eFlyer 2 features a cantilever low-wing, a two-seat side-by-side configuration enclosed cockpit under a bubble canopy, fixed tricycle landing gear and a single electric motor in tractor configuration powered by up to six Lithium-ion battery packs.[2][5][3][21]

The design has a gross weight of 1,900 lb (860 kg)[2] and is made from composite material, primarily carbon fibre. The cockpit employs an iPad used for cockpit instrumentation display, including motor, battery and aircraft systems. The aircraft connects to Redbird Flight Simulations' Sidekick system, which wirelessly tracks the eFlyer's motor, flight time, physical location and attitude in real time when in flight.[2][5]

The previously-used 57 lb (26 kg) Siemens SP70D had a takeoff rating of 90 kW (120 hp) and 70 kW (94 hp) continuous. Utah-based Electric Power Systems provides the 92-kWh energy storage including battery modules, management and distribution. The 138 kn (256 km/h) cruise aircraft is projected to have hourly operating costs one-sixth of a piston-powered Cessna 172.[15]

The Safran motor announced in November 2020 will be from the ENGINeUS 100 line.[22]

Operational history[edit]

By February 2019, one example, the prototype, had been registered in the United States with the Federal Aviation Administration.[23]

By December 2018 the company had 220 deposits, split evenly between the eFlyer 2 and eFlyer 4,[20] growing to 298 by April 2019.[16] In December 2020, the company indicated it had 711 purchase agreements.[24]


The following organizations have ordered the aircraft:

Specifications (eFlyer 2)[edit]

Data from AVweb[2]

General characteristics

  • Crew: one
  • Capacity: one passenger
  • Wingspan: 38 ft (12 m)
  • Wing area: 129 sq ft (12.0 m2)
  • Empty weight: 1,460 lb (662 kg)
  • Gross weight: 1,900 lb (862 kg)
  • Powerplant: 1 × Safran electric motor with up to six lithium-ion battery packs, 115 hp (90 kW)
  • Propellers: 3-bladed composite


  • Maximum speed: 135 kn (155 mph, 250 km/h)
  • Endurance: 3.5 hours
  • Maximum glide ratio: 20.6:1
  • Rate of climb: 1,050 ft/min (5.3 m/s)

See also[edit]

Related development

Aircraft of comparable role, configuration, and era

Related lists


  1. ^ Bye Aerospace (12 March 2019). "Bye Aerospace Relocates to Larger Hangar as Flight Tests Continue". Bye Aerospace. Retrieved 2 April 2019.
  2. ^ a b c d e f g Mary Grady (July 23, 2015). "Sun Flyer Promises Three-Hour Flight Time". AVweb. Archived from the original on 29 August 2020. Retrieved 29 August 2020.
  3. ^ a b c d e Elaine Kauh (May 11, 2016). "Sun Flyer Proof-Of-Concept Model Rolls Out". AVweb.
  4. ^ "Sun Flyer Prototype On Assembly Line". AVweb. July 20, 2015.
  5. ^ a b c "Sun Flyer Prototype Readying For Final Tests". AVweb. March 4, 2016.
  6. ^ Kauh, Elaine (17 November 2016). "Sun Flyer Begins Ground, Taxi Tests". AVweb. Retrieved 18 November 2016.
  7. ^ Huber, Mark (July 26, 2017). "Electric Sun Flyer Plans Fall First Flight". AIN Online. Retrieved 2017-10-26.
  8. ^ Cobb, Alyssa J. (July 24, 2017). "Four-Seat Sun Flyer in the Works". AOPA. Retrieved 2017-10-26.
  9. ^ "Bye Aerospace Announces First Flight of Sun Flyer 2" (Press release). Bye Aerospace. 11 April 2018. Archived from the original on 30 October 2020. Retrieved 19 February 2019.
  10. ^ Grady, Mary (11 April 2018). "First Flight For Sun Flyer 2". AVweb. Retrieved 15 April 2018.
  11. ^ Bye AeroSpace (2017). "Projects". Archived from the original on 25 September 2017. Retrieved 15 April 2019.
  12. ^ Mark Huber (October 18, 2018). "Bye Pitches Electric Aircraft for Charter". AIN online.
  13. ^ Graham Warwick (Jan 14, 2019). "The Week In Technology, Jan. 14-18, 2019". Aviation Week & Space Technology.
  14. ^ Niles, Russ (17 February 2019). "Sun Flyer Flies With Siemens". AVweb. Retrieved 18 February 2019.
  15. ^ a b Graham Warwick (Feb 18, 2019). "The Week In Technology, Feb. 18-22, 2019". Aviation Week & Space Technology.
  16. ^ a b c d Dalløkken, Per Erlien (12 April 2019). "OSM Aviation legger inn tidenes største elfly-bestilling". (in Norwegian). Teknisk Ukeblad.
  17. ^ "Bye Aerospace and Safran announce Cooperation Agreement to equip eFlyer all-electric aircraft with ENGINeUS electric smart motors". Bye Aerospace. 16 November 2020. Archived from the original on 2020-11-16. Retrieved 16 November 2020.
  18. ^ "Bye Shifts to Safran". 2 December 2020. Archived from the original on 2021-04-20. Retrieved 4 December 2020.
  19. ^ Phelps, Mark (30 July 2021). "Bye Aerospace Lays Out Its Aggressive Aircraft Development Agenda". AVweb. Archived from the original on 7 May 2021. Retrieved 15 July 2021.
  20. ^ a b "Projects". Bye Aerospace. Archived from the original on 2017-09-25. Retrieved 2018-03-20.
  21. ^ Grady, Mary (29 May 2018). "Siemens Electric Motor Will Power Sun Flyer 2". AVweb. Retrieved 30 May 2018.
  22. ^ "Safran and Bye Aerospace announce cooperative agreement". Safran Electrical Power. Archived from the original on 2020-11-16. Retrieved 16 November 2020.
  23. ^ "Registry inquiry". Federal Aviation Administration. 19 February 2019. Retrieved 19 February 2019.
  24. ^ "Bye shifts to Safran". 2 December 2020. Archived from the original on 2021-04-20. Retrieved 4 December 2020.
  25. ^ "OSM Aviation aims for a Green Future!". 11 April 2019. Retrieved 12 April 2019.
  26. ^ Dan Johnson (May 23, 2016). "Sun Catches Lightning – Sun Flyer Rollout".

External links[edit]