Zunum Aero

Zunum Aero (Mayan for hummingbird) is an aircraft manufacturer startup based in Kirkland, Washington. Backed by Boeing HorizonX and JetBlue Technology Ventures, the company has been working since 2013 on a family of hybrid electric regional aircraft up to 50 seats.

Zunum Aero
Key people
Ashish Kumar, CEO
Matt Knapp, CTO
ProductsElectric aircraft
Number of employees
70 (Oct 2018)[1]


Zunum planned to fly a prototype in 2019 or 2020. Under the revamped FAR Part 23 rules for electric aircraft standards expected by 2018 and with first type certification by 2020, a 19-seat design optimized for a 700 nmi (1,300 km) range, viable on a battery specific energy of 300 watt hours per kilogram available in 2017, was to begin service in the early 2020s. Range might increase to beyond 1,000 nmi (1,900 km) by 2030 with in-service aircraft upgrades made possible by technology advances.[2] A 4 MW (5,400 hp) hybrid-electric 50 seater is planned before 2030.[3] Zunum targets the $1 trillion market of regional aircraft.[4]

A $800,000 research and development grant from Washington state’s Clean Energy Fund matches funding raised from Boeing and JetBlue. Zunum's workforce is expected to grow from 10 in mid 2017 to 20-25 by year-end. The company then expects to fly an existing twin-turboprop testbed in 2018 with commercial off-the-shelf motors. The prototype will then be modified in stages to demonstrate the propulsion system with custom lightweight motors for unducted propellers initially, then ducted fans, as designers focus on producing an electric powertrain for an airframe.[5]

In April 2017, JetBlue Technology Ventures and Boeing HorizonX invested a combined $6.2 million in Series A funding.[6] Zunum needed $50 million in Series B funding since February 2018 and received bridge loans from JetBlue and Boeing in April, allowing hiring in the summer of 2018.[6] By December 2018, Zunum Aero had trouble raising funds, maybe delaying its plans.[7] Nearly all of the 70-person staff was laid off in November, while unpaid wage complaints pile on, an in-development a 500 kW (670 hp) electric motor was seized by creditors in Elgin, Illinois and headquarters in Bothell near Seattle and facilities in Indianapolis had closed.[6]


The architecture is a series hybrid, with ducted fans powered by batteries alone for short trips and a range-extending generator providing 1 MW (1,300 hp) to 4–5 MW (5,400–6,700 hp). The design targets 40-80% lower operating costs thanks to power grid electricity rather than aviation fuel, including replacing the rechargeable battery packs every six months after 1,000-1,500 cycles.[2]

More frequent service from local airports can be provided by smaller aircraft for better transportation at ranges of 87–869 nmi; 160–1,610 km. Travel times for San Francisco to Los Angeles (300 nmi, 560 km) or Boston to Washington (350 nmi, 650 km) could be halved using secondary airports with only carry-on luggage not needing baggage conveyor belts and requiring less elaborate airport security. All-weather access to small airports will be provided by the Air Traffic Organization NextGen system, with turnarounds as short as 10 minutes for battery swaps or fast chargers.[2]

Extending natural laminar flow to reduce drag was preferred to boundary-layer ingestion and wingtip propulsors, as their benefits were insufficient for small aircraft or they introduced issues. The range extender will be an off-the-shelf turbine before future improvements like an inflight shutdown/quick restart capability. It will be used at first to meet FAA reserves, then replaced later with a third battery pack for a 45-minute reserve.[5]

Six-to-12-seat ZA10Edit

Zunum small aircraft concept


On 5 October 2017, Zunum Aero formally launched the development of a six-to-12-seat aircraft aimed to fly in 2020 and be delivered in 2022. The powertrain will be installed on a testbed and flown in 2019 from Zunum Aero facilities near Chicago.[8]

In May 2018, private jet charter JetSuite was announced as the launch customer for the nine-passenger hybrid available from 2022, with up to 100 aircraft. Zunum investor JetBlue Airways is also a strategic investor in JetSuite, led by founding JetBlue executive Alex Wilcox. JetSuiteX operates Embraer ERJ-135s from private air terminals seating 30 to avoid TSA screening between Burbank, Concord and Oakland in California and Las Vegas.[9]

In October 2018, Zunum selected Safran to supply a new 3Z variant of its 1,700-2,000 hp (1,270-1,500 kW) Ardiden turboshaft, delivering 500kW with an electric generator. Ground tests of the hybrid-electric power system began in early 2018 and will continue through 2019. A Rockwell Turbo Commander 840, with similar weight and performance, will begin flight tests in the second half of 2019, and will be upgraded until certification starts in 2020-2021.[3]

At the time, Zunum had built a test ducted fan, switched on the inverters, is assembling its first motor and developing control laws. One testbed turboprop will be replaced with the electric motor driving the same propeller through a gearbox, to fly in summer 2019 powered by batteries only. The turbogenerator will then be installed and flown by the end of 2019, before replacing the propeller by the ducted-fan and then tuning the control software. Turbogenerator and batteries will each provide about half the power required initially, before batteries improves and could take over. The battery pack energy density should be upgraded regularly, to increase range from 700 to 1,000 mi (1,100 to 1,600 km) between 2020 and 2030. The evolving batteries should be certified every two years and introduced often as they may have short cycle lives at high utilization rates.[10]

Zunum will decide the basic airframe configuration, sizing and materials by early 2019, and then reach to aerostructures suppliers to design and assemble components: Spirit AeroSystems in Kansas; Triumph Group in Pennsylvania; Daher of France; Aernnova of Spain; and Bombardier Aerostructures in Northern Ireland. Systems integration and final assembly should stay Washington state and the first production aircraft flight tests will start in late 2021. Zunum wants to start final FAA certification in 2022, with introduction slipping out a year to mid-2023.[1]


Wing batteries are supplemented by a 1MW (1,350 hp) gas turbine driving two 500 kW generators to extend range to 700 nm (1,300 km). Generators could be supplied by GE Aviation, Honeywell, Rolls-Royce plc or UTC Aerospace Systems. Fuel savings from hybrid-electric propulsion and FAR Part 23 certification allowing single pilot operations for nine seats would lower operating costs by 40-80% to reach available seat miles (ASM) costs of a 78-seat Dash 8-Q400. Controlled by fly-by-wire, the aircraft could also fly without a pilot.[8] Initial performance is based on the current energy densities achieved at the Tesla Gigafactory.[11] The wing battery packs have to accept two or more cells overheating without spreading in a fire: should the battery fail, the turbogenerator's 500 kW are enough to cruise and land.[1]

Its purchase cost should stay below the list price of a $4.5 million single-engine turboprop like the Pilatus PC-12 or Cessna Denali.[8] Zunum targets a $250 hourly operating cost including fuel, electricity, and batteries, or 8 cents per ASM. This would be inferior to a Boeing 737 for 300–500 mi (480–800 km) sectors, comparable to a Q400 over 300–400 mi (480–640 km), and 3 to 5 times cheaper than a similarly sized PC-12 or Beechcraft King Air.[11]


Data from Zunum Aero[12]

General characteristics

  • Crew: 0, 1 or 2
  • Capacity: 2,500 lb (1,134 kg) payload, 12 economy or 9 premium or 6 executive
  • Length: 42 ft (13 m)
  • Wingspan: 52 ft (16 m)
  • Height: 18 ft (5.5 m)
  • Empty weight: 8,200 lb (3,719 kg)
  • Max takeoff weight: 11,500 lb (5,216 kg)
  • Fuel capacity: 800 lb (363 kg), <2,300 lb (1,043 kg) batteries
  • Powerplant: 1 × Series hybrid , 1,300 hp (1,000 kW) , two ducted fans
  • Powerplant: 1 × Safran Ardiden 3 turbogenerator, 670 hp (500 kW) range extender


  • Cruise speed: 340 mph (550 km/h, 300 kn) max
  • Stall speed: 84 mph (135 km/h, 73 kn) IAS
  • Range: 700 mi (1,100 km, 610 nmi)
  • Service ceiling: 25,000 ft (7,600 m)
  • Time to altitude: 18min to FL250
  • Fuel consumption: 0 to 0.0955 lb/mi (0.0000 to 0.0269 kg/km), per seat
  • Takeoff: 2,200 ft (671 m)
  • Landing: 2,500 ft (762 m)

See alsoEdit

Aircraft of comparable role, configuration and era


  1. ^ a b c d Dominic Gates (October 4, 2018). "Rapidly shifting battery technology complicates Zunum's plans for hybrid electric airplane Originally". Seattle Times.
  2. ^ a b c d Graham Warwick (Apr 5, 2017). "Boeing, JetBlue Back Hybrid-Electric Regional Startup". Aviation Week & Space Technology.
  3. ^ a b Michael Gubisch (4 Oct 2018). "Zunum picks Safran for developmental hybrid-electric commuter". Flightglobal.
  4. ^ Chad Trautvetter (May 21, 2018). "JetSuite Plans a Future with Hybrid Electric Aircraft". AIN online.
  5. ^ a b Graham Warwick (Jul 4, 2017). "Zunum's Software-Style Approach To Developing Electric Propulsion". Aviation Week & Space Technology. Regional-aircraft startup explores new ways to mature and improve propulsion systems.
  6. ^ a b c Jeremy Bogaisky (Jul 2, 2019). "Boeing Backs Away From Zunum Aero, Founders Struggle To Raise Money After Laying Off Staff". Forbes.
  7. ^ Dan Catchpole (January 3, 2019). "Zunum Runs Into Financing Trouble". AIN online.
  8. ^ a b c Stephen Trimble (Oct 5, 2017). "Zunum launches hybrid-electric aircraft for regional market". Flightglobal.
  9. ^ Graham Warwick (May 21, 2018). "JetSuite Is Launch Customer For Zunum's Hybrid-Electric Regional". Aviation Week Network.
  10. ^ Graham Warwick (Oct 4, 2018). "Zunum Picks Safran Turbine For Hybrid-Electric Airliner". Aviation Week & Space Technology.
  11. ^ a b Graham Warwick (Oct 5, 2017). "Boeing-Backed Zunum's First Aircraft To Be 12-seat Commuter". Aviation Week & Space Technology.
  12. ^ "Aircraft". Zunum Aero.

External linksEdit