The Ampaire Electric EEL is a

hybrid electric aircraft A hybrid electric aircraft is an aircraft with a hybrid electric powertrain. As the energy density of lithium-ion batteries is much lower than aviation fuel, a hybrid electric powertrain may effectively increase flight range compared to pure electri ...

developed by U.S. startup

Ampaire Ampaire is an American aircraft manufacturer startup based in Hawthorne, California. History The company developed the Electric EEL, based on a Cessna 337 Skymaster (a push-pull aircraft) with a piston engine replaced by an electric motor ...

, established in

Hawthorne, California Hawthorne is a city in the Los Angeles metropolitan area, located in southwestern Los Angeles County, California. It is part of a seventeen-city region commonly called the South Bay. As of the 2020 US census, Hawthorne had a population of 88,0 ...

. The forward piston engine of a

Cessna 337 Skymaster The Cessna Skymaster is an American twin-engine civil utility aircraft built in a push-pull configuration. Its engines are mounted in the nose and rear of its pod-style fuselage. Twin booms extend aft of the wings to the vertical stabilizers, ...

(a push-pull aircraft) is replaced by an electric motor powered by a battery, in a

parallel hybrid Hybrid vehicle drivetrains transmit power to the driving wheels for hybrid vehicles. A hybrid vehicle has multiple forms of motive power. Hybrids come in many configurations. For example, a hybrid may receive its energy by burning gasoline, but sw ...

configuration. The demonstrator first flew on 6 June 2019.

Design

Ampaire is replacing the

(a push-pull aircraft) forward piston engine with an electric motor. The forward

Continental IO-360 The Continental IO-360 is a family of fuel-injected air-cooled, horizontally opposed six-cylinder aircraft engines manufactured by Continental Motors in the United States of America, now part of AVIC International since 2010. The engine is a ...

piston engine is replaced with an electric motor powered by a battery in a

configuration, optimising power output to reduce operating costs and pollution. The

centerline thrust An aircraft constructed with a push-pull configuration has a combination of forward-mounted tractor (pull) propellers, and backward-mounted ( pusher) propellers. Historical The earliest known examples of "push-pull" engined-layout aircraft incl ...

makes the 337 a useful testbed, allowing thrust differences with no yawing unlike a conventional twin-engine aircraft. Ampaire is marketing the EEL to government departments and private owners while undisclosed commercial operators already placed orders. Manufactured between 1965 and 1982, there is in-service fleet of 2,500 of the six-seat aircraft. EEL refers to the original 337 designation, with the

character Character or Characters may refer to: Arts, entertainment, and media Literature * ''Character'' (novel), a 1936 Dutch novel by Ferdinand Bordewijk * ''Characters'' (Theophrastus), a classical Greek set of character sketches attributed to The ...

s reversed. Ampaire wants to offer multiple single and twin-engined aircraft, powered by its proprietary electric-propulsion system.

Development

By January 2019, Ampaire planned to fly the prototype on Hawaiian

Mokulele Airlines Southern Airways Express, doing business as Mokulele Airlines, is an American commuter airline operating in Hawaii. The airline operates scheduled inter-island and charter flights among all Hawaiian islands with airports. Mokulele Airlines wa ...

commuter routes operated with

Cessna Caravan The Cessna 208 Caravan is a utility aircraft produced by Cessna. The project was commenced on November 20, 1981, and the prototype first flew on December 9, 1982. The production model was certified by the FAA in October 1984 and its Cargomas ...

s. Seven other airlines are interested by Caravan or

Twin Otter The de Havilland Canada DHC-6 Twin Otter is a Canadian STOL (Short Takeoff and Landing) utility aircraft developed by de Havilland Canada, which produced the aircraft from 1965 to 1988; Viking Air purchased the type certificate, then restarted ...

conversions: Seattle's

Kenmore Air Kenmore Air Harbor, Inc., doing business as Kenmore Air, is an American airline with its headquarters on the grounds of Kenmore Air Harbor in Kenmore, Washington, United States, north of Seattle. It operates scheduled and charter seaplane and lan ...

Tropic Air Tropic Air is an airline operating scheduled services from Belize. Founded in 1979 by John Greif III with just a single airplane and two employees, Tropic has steadily grown to a fleet of 17 light aircraft. The airline flies to 17 destinations in ...

of Belize, Puerto Rico-based

Vieques Air Link Vieques Air Link (VAL, IATA code:V4) is a small Puerto Rico-based airline that links Vieques with Culebra and mainland Puerto Rico. History Operations began during 1965, with owner Osvaldo "Val" Gonzalez-Duriex piloting a plane with three ...

Southern Airways Express Southern Airways Express is a commuter airline operating across the United States with headquarters in Palm Beach, Florida. Southern Airways acts as a local service airline for dozens of cities across all U.S. time zones, Approximately a third ...

of Memphis, Tennessee, Guernsey's

Aurigny Aurigny Air Services Limited (pronounced ), commonly known as Aurigny, is the flag carrier airline of the Bailiwick of Guernsey with its head office next to Guernsey Airport in the Channel Islands, and wholly owned by the States of Guernsey ...

and

Star Marianas Air Star Marianas Air, Inc. is a U.S. commuter airline headquartered at Tinian International Airport in Tinian Municipality, Northern Mariana Islands. It operates scheduled and charter passenger service in the Commonwealth of the Northern Mariana ...

, based in the Northern Mariana Islands, as well as

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

. Test flights will take place on a route over 15 minutes between

Kahului Airport Kahului Airport is the main airport of Maui in the State of Hawaii, United States, located east of Kahului. It has offered full airport operations since 1952. Most flights into Kahului Airport originate from Daniel K. Inouye International Ai ...

in Central Maui and

Hana Airport Hana or HANA may refer to: Places Europe * Haná, an ethnic region in Moravia, Czech Republic * Traianoupoli, Greece, called Hana during the Ottoman period * Hana, Norway, a borough in the city of Sandnes, Norway West Asia * Hana, Iran, a city ...

on the East side. The hybrid prototype held its first public test flight on June 6, 2019, before scheduled service planned for 2021. Later that month,

Personal Airline Exchange Personal may refer to: Aspects of persons' respective individualities * Privacy * Personality * Personal, personal advertisement, variety of classified advertisement used to find romance or friendship Companies * Personal, Inc., a Washington ...

(PAX) became the launch customer for the electric EEL modified six-seat Skymaster, to be certified in 2021, with an order for 50 plus 50 options. US start-up PAX is an on-demand per-seat

charter A charter is the grant of authority or rights, stating that the granter formally recognizes the prerogative of the recipient to exercise the rights specified. It is implicit that the granter retains superiority (or sovereignty), and that the rec ...

offering point-to-point service competing with driving, is connecting small airports to bypass hubs and congested roads. PAX will acquire two Cessna 337s, sourced and refurbished by Ampaire, to start commercial operations in early 2020 in southern California before a nationwide introduction, with their original engines. A second prototype was first flown in September 2020. With this second prototype, Hawaiian regional carrier

will experiment connecting

Maui The island of Maui (; Hawaiian: ) is the second-largest of the islands of the state of Hawaii at 727.2 square miles (1,883 km2) and is the 17th largest island in the United States. Maui is the largest of Maui County's four islands, which ...

airports. It will be limited to a pilot and two non-paying passengers, below its six-seat capacity, and Mokulele will provide hangar space, parts, pilots and maintenance. A similar pilot project is supported by

, a regional airline in

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...

. The certification and service entry of the EEL is planned for 2021. The prototype was originally configured with the electric motor replacing the aft engine, but by October 2019 the configuration was swapped with the piston engine in the back and the electric system forward. This redesign also moved the batteries outside the cabin into a belly pod. In 2020, Scottish regional carrier

Loganair Loganair is a Scottish regional airline based at Glasgow Airport near Paisley, Scotland. It is the largest regional airline in the UK by passenger numbers and fleet size. In addition to its main base at Glasgow, it has hubs at Aberdeen, Edinb ...

trialled the Electric EEL with 70%

fuel savings Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier ( fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, ...

for short hops and 50% for longer flights of 50-250 miles (80-400km). In August 2021, tests were conducted in the

Orkney islands Orkney (; sco, Orkney; on, Orkneyjar; nrn, Orknøjar), also known as the Orkney Islands, is an archipelago in the Northern Isles of Scotland, situated off the north coast of the island of Great Britain. Orkney is 10 miles (16 km) north ...

, including the aircraft's first flight across open water between

Kirkwall Kirkwall ( sco, Kirkwaa, gd, Bàgh na h-Eaglaise, nrn, Kirkavå) is the largest town in Orkney, an archipelago to the north of mainland Scotland. The name Kirkwall comes from the Norse name (''Church Bay''), which later changed to ''Kirkv ...

and

Wick Wick most often refers to: * Capillary action ("wicking") ** Candle wick, the cord used in a candle or oil lamp ** Solder wick, a copper-braided wire used to desolder electronic contacts Wick or WICK may also refer to: Places and placenames ...

. Further demonstration flights are then expected to occur between

Exeter Exeter () is a city in Devon, South West England. It is situated on the River Exe, approximately northeast of Plymouth and southwest of Bristol. In Roman Britain, Exeter was established as the base of Legio II Augusta under the personal comm ...

and

Newquay Newquay ( ; kw, Tewynblustri) is a town on the north coast in Cornwall, in the south west of England. It is a civil parish, seaside resort, regional centre for aerospace industries, spaceport and a fishing port on the North Atlantic coast of ...

south west England South West England, or the South West of England, is one of nine official regions of England. It consists of the counties of Bristol, Cornwall (including the Isles of Scilly), Dorset, Devon, Gloucestershire, Somerset and Wiltshire. Cities and ...

References

{{reflist Proposed aircraft of the United States Hybrid electric aircraft

Design

Development

See also

References