Solar-powered aircraft
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An electric aircraft is an
aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
powered by
electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
. Electric aircraft are seen as a way to reduce the
environmental effects of aviation Like other emissions resulting from fossil fuel combustion, aircraft engines produce gases, noise, and particulates, raising environmental concerns over their global effects and their effects on local air quality. Jet airliners contribute ...
, providing zero emissions and quieter flights. Electricity may be supplied by a variety of methods, the most common being batteries. Most have
electric motor An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...
s driving propellers or turbines. Crewed flights in an electrically powered
airship An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early ...
go back to the 19th century, and to 1917 for a tethered
helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...
. Electrically powered model aircraft have been flown at least since the 1970s, preceding the small
unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
s (UAV) or drones used today. Small UAS could be used for parcel deliveries, and larger ones for long-endurance applications: aerial imagery, surveillance, telecommunications. The first crewed free flight by an electrically powered
aeroplane An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectr ...
, the MB-E1, was made in 1973, and most crewed electric aircraft today are still only experimental prototypes. Between 2015 and 2016,
Solar Impulse 2 Solar Impulse is a Swiss long-range experimental solar-powered aircraft project, and also the name of the project's two operational aircraft. The privately financed project is led by Swiss engineer and businessman André Borschberg and Swiss p ...
completed a circumnavigation of the Earth using solar power. Electric
VTOL A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...
aircraft or
personal air vehicle A personal air vehicle (PAV) is a proposed type of aircraft providing on-demand aviation services. The emergence of this alternative to traditional ground transport methods has been enabled by unmanned aerial vehicle technologies and electric pr ...
s are being considered for Urban Air Mobility. Electric
commercial airliner An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ai ...
s could lower operating costs.


Environmental effects of aviation

The
environmental effects of aviation Like other emissions resulting from fossil fuel combustion, aircraft engines produce gases, noise, and particulates, raising environmental concerns over their global effects and their effects on local air quality. Jet airliners contribute ...
on
climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
have become a major driving force for the development of electric aircraft, with a zero-emissions electric powertrain being the goal for some development teams. Aviation accounts for 2.4% of all fossil fuel derived emissions, and its emissions of air transportation altogether increased by 32% between 2013 and 2018. While estimating aviation's non- effects on climate change is complex,
NOx In atmospheric chemistry, is shorthand for nitric oxide () and nitrogen dioxide (), the nitrogen oxides that are most relevant for air pollution. These gases contribute to the formation of smog and acid rain, as well as affecting tropos ...
and
contrail Contrails (; short for "condensation trails") or vapor trails are line-shaped clouds produced by aircraft engine exhaust or changes in air pressure, typically at aircraft cruising altitudes several miles above the Earth's surface. Contrails ar ...
s could increase this responsibility to 3.5%. Other benefits are the potential for noise reduction, in an industry with a severe
noise pollution Noise pollution, also known as environmental noise or sound pollution, is the propagation of noise with ranging impacts on the activity of human or animal life, most of them are harmful to a degree. The source of outdoor noise worldwide is main ...
and
abatement Abatement refers generally to a lessening, diminution, reduction, or moderation; specifically, it may refer to: * 421-a tax abatement, property tax exemption in the U.S. state of New York * Abatement of debts and legacies, a common law doctrine ...
problem, as well as the removal of lead emissions for general aviation using 100LL fuel.


Offboard power supply

Mechanisms for supplying the necessary electricity without storing all of it onboard include: *
Solar cell A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.
s convert sunlight directly into electricity using
photovoltaic Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commercially us ...
materials. *
Microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ran ...
energy that is beamed from a remote transmitter. *
Power cable A power cable is an electrical cable, an assembly of one or more electrical conductors, usually held together with an overall sheath. The assembly is used for transmission of electrical power. Power cables may be installed as permanent wiring wi ...
s connected to a ground-based electrical supply.


Solar cells

A
solar cell A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.
converts sunlight directly into electricity, either for direct power or temporary storage. The power output of solar cells is low and requires that many be connected together, which limits their use. Typical solar panels running at 15–20% conversion efficiency (sunlight energy to electrical power) produce about in direct sunlight. Usable areas are further limited as output from a poorly performing panel impacts the output of all the panels on its circuit, meaning they all require similar conditions, including being at a similar angle to the sun, and not being masked by shadow. Between 2010 and 2020, solar power modules have declined in cost by 90% and continue to drop by 13–15% per year.
Solar cell efficiency Solar-cell efficiency refers to the portion of energy in the form of sunlight that can be converted via photovoltaics into electricity by the solar cell. The efficiency of the solar cells used in a photovoltaic system, in combination with lat ...
has also risen substantially, from 2% in 1955 to 20% in 1985, and some experimental systems now exceed 44%. However, most of the technologies at these high efficiencies have only been possible under laboratory settings and not at full scale production level. The free availability of sunlight makes solar power attractive for high-altitude, long-endurance applications, where the cold and reduced atmospheric interference make them significantly more efficient than on the ground. The drop in the dry-air temperature as altitude increases, called the environmental lapse rate (ELR), averages 6.49 °C/km (memorized in pilot training as 1.98 °C/1,000 ft or 3.56 °F/1,000 feet) so that temperature for a typical airliner's cruising altitude of around will be substantially lower than at ground level. Night flying, such for endurance flights and with aircraft providing 24 hour coverage over an area typically require a backup storage system, which is charged during the day from surplus power, and supplies power during the hours of darkness.


Microwaves

Power beaming Wireless power transfer (WPT), wireless power transmission, wireless energy transmission (WET), or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system, ...
of electromagnetic energy such as
microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ran ...
s relies on a ground-based power source. However, compared to using a power cable, power beaming allows the aircraft to move laterally and carries a much lower weight penalty, particularly as altitude increases. The technology has only been demonstrated on small models and awaits practical development at larger scales.


External power cables

For powered vehicles replacing tethered
aerostat An aerostat (, via French) is a lighter-than-air aircraft that gains its lift through the use of a buoyant gas. Aerostats include unpowered balloons and powered airships. A balloon may be free-flying or tethered. The average density of the cra ...
s, an electrical
power cable A power cable is an electrical cable, an assembly of one or more electrical conductors, usually held together with an overall sheath. The assembly is used for transmission of electrical power. Power cables may be installed as permanent wiring wi ...
can be connected to a ground-based supply, such as an electric generator or the local
power grid An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:Kaplan, S. M. (2009). Smart Grid. Electrical Power ...
. At low altitudes this avoids having to lift batteries, and was used by the experimental Petróczy-Kármán-Žurovec PKZ-1 observation vehicle of 1917. However the higher it flies, the heavier the length of cable it lifts becomes.


Power storage

Mechanisms for storing the necessary electricity include: * Batteries which use a chemical reaction to generate electricity which is reversed when recharged. *
Fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
s consume fuel and an oxidizer in a chemical reaction to generate electricity, they need to be refueled, typically with hydrogen.


Batteries

Batteries are the most common onboard
energy storage Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in ...
component of electric aircraft, due to their relatively high storage capacity. Batteries first powered airships in the nineteenth century but the lead-acid batteries were very heavy and it was not until the arrival of other chemistries, such as nickel-cadmium (NiCd) later in the twentieth century, that batteries became practical for
heavier-than-air aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
. Modern batteries are mostly rechargeable types based on lithium technologies. Lithium polymer (LiPo), a type of lithium-ion batteries (LIB), have long been applied in unmanned flight for their light weight and rechargeability. However, their energy density limits their application mostly to being drone batteries. Increasing maximum time of flight by simply designing larger aircraft using larger batteries is inefficient, because of the payload-range compromise. After a certain increase in battery weight, there are diminishing returns through the mass penalty not outweighing the increase in battery specific energy. There is a similar trade-off between the maximum range and number of passengers. Computational tools have been used to model this trend, predicting that a small-scale electric aircraft of average weight (1500 kg) and average energy density (150 Wh/kg) could travel a range of ~80 mi with one passenger, ~60 mi with two, and less than ~30 mi with three. In 2017 the power available from batteries was estimated at around 170 Wh/kg, 145 Wh/kg at the shaft including the system efficiency, while a
gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...
extracted 6,545 Wh/kg of shaft power from an 11,900 Wh/kg fuel. In 2018
Lithium-ion batteries A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also se ...
including packaging and accessories were estimated to give 160 Wh/kg while aviation fuel gave 12,500 Wh/kg. In 2018 the
specific energy Specific energy or massic energy is energy per unit mass. It is also sometimes called gravimetric energy density, which is not to be confused with energy density, which is defined as energy per unit volume. It is used to quantify, for example, sto ...
of
electricity storage Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an Accumulator (energy), accumulator or Batte ...
was still only 2% of
aviation fuel Aviation fuels are petroleum-based fuels, or petroleum and synthetic fuel blends, used to power aircraft. They have more stringent requirements than fuels used for ground use, such as heating and road transport, and contain additives to enhanc ...
. This 1:50 ratio makes electric propulsion impractical for long-range aircraft, as a mission for an all-electric, 12-passenger aircraft would require a six-fold increase in battery power density. That said, battery-electric motors have a higher efficiency (~90%) than most jet engines (~50%), which can be further exploited through emerging battery chemistries. To be feasible for electric aircraft application, it is essential that power storage be improved. Energy density is widely recognized to be the bottleneck for zero-emission electric powertrain. Another limitation is the discharge rate due to demand-pack energy ratio and sensitive mission segments, as the discharge C-rate for take-off is 4C while it is almost 5C for landing. Electric aircraft have additional heat generation and end-of-life needs, requiring novel thermal management strategies, power-fade capabilities and battery pack failure modes. As of 2019, the best Li-ion batteries achieved 250–300 Wh/kg, sufficient for a small aircraft, while a regional airliner would have needed a 500 Wh/kg battery pack and an
Airbus A320 The Airbus A320 family is a series of Narrow-body aircraft, narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, Maiden flight, first flew on 22 February 1987, and was introduced in April 1988 by Air F ...
-sized single-aisle would need 2 kWh/kg. Electric power is only suitable for small aircraft while for large passenger aircraft, an improvement of the energy density by a factor 20 compared to li-ion batteries would be required. Such batteries can reduce the overall operating costs for some short-range flights. For example, the electricity used in the Harbour Air Beavers costs them around $ Canadian per kWh compared to $2.00 per liter for gas, providing of energy with a 44 MJ/kg fuel and a 0.75 density
Avgas Avgas (aviation gasoline, also known as aviation spirit in the UK) is an aviation fuel used in aircraft with spark-ignited internal combustion engines. ''Avgas'' is distinguished from conventional gasoline (petrol) used in motor vehicles, w ...
, $ per chemical kWh or $ per shaft kWh with an efficiency of one third.
Jet fuel Jet fuel or aviation turbine fuel (ATF, also abbreviated avtur) is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is colorless to straw-colored in appearance. The most commonly used fuels for commercial a ...
is cheaper and large gas turbine are more efficient, though. In 2021, beyond-lithium-ion technologies such as
Solid-state battery A solid-state battery is a battery technology that uses solid electrodes and a solid electrolyte, instead of the liquid or polymer gel electrolytes found in lithium-ion or lithium polymer batteries. While solid electrolytes were first discovered ...
( lithium-sulfur, LSB) and lithium-air batteries (LAB) have become increasingly promising areas of research for more competitive battery-electric aircraft performance. The
SAE International SAE International, formerly named the Society of Automotive Engineers, is a United States-based, globally active professional association and standards developing organization for engineering professionals in various industries. SAE Internatio ...
AE-7D committee was formed by Electro.Aero in 2018 to standardise electric aircraft charging and energy storage. One of the first documents developed was the AS6968 standard for sub-megawatt electric aircraft charging of electric aircraft. The AE-7D committee is also developing Aerospace Information Report AIR7357 for megawatt power level charging. Some airports have
charging station A charging station, also known as a charge point or electric vehicle supply equipment (EVSE), is a piece of equipment that supplies electrical power for charging plug-in electric vehicles (including electric cars, electric trucks, electric ...
s for
electric car An electric car, battery electric car, or all-electric car is an automobile that is propelled by one or more electric motors, using only energy stored in batteries. Compared to internal combustion engine (ICE) vehicles, electric cars are quie ...
s which can also charge aircraft.


Ultracapacitors

An
ultracapacitor A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, with a capacitance value much higher than other capacitors but with lower voltage limits. It bridges the gap between electrolytic capacitors and rechargeable b ...
is a hybrid electrochemical energy storage system bridging batteries and capacitors, and has some advantages over batteries in being able to charge and discharge much faster with higher peak currents, while not being as limited in the number of charge-discharge cycles, as the reaction is not just chemical but also electrical. Their energy density, typically around 5 Wh/kg, is however well below that of batteries, and they are considerably more expensive, even when their longer lifespan is factored in.


Fuel cells

A
fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
(FC) uses the reaction between two chemicals such as
hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
and
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
to create electricity, much like a
liquid-propellant rocket A liquid-propellant rocket or liquid rocket utilizes a rocket engine that uses liquid rocket propellant, liquid propellants. Liquids are desirable because they have a reasonably high density and high Specific impulse, specific impulse (''I''sp). T ...
motor, but generating electricity in a controlled chemical reaction, instead of thrust. While the aircraft must carry the hydrogen (or a similar fuel), with its own complications and risks, the oxygen can be obtained from the atmosphere.


Propulsion


Electric motors

Almost all electric aircraft to date have been powered by
electric motor An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...
s driving thrust-generating
propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
s or lift-generating
rotor Rotor may refer to: Science and technology Engineering *Rotor (electric), the non-stationary part of an alternator or electric motor, operating with a stationary element so called the stator * Helicopter rotor, the rotary wing(s) of a rotorcraft ...
s. While the batteries weigh more than the equivalent in fuel, electric motors weigh less than their piston-engine counterparts and in smaller aircraft used for shorter flights, can partly offset the disparity between electric and gasoline energy densities. Electric motors also do not lose power with altitude, unlike internal-combustion engines, avoiding the need for complex and costly measures used to prevent this, such as the use of
turbocharger In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...
s. The experimental
Extra 330 The Extra Flugzeugbau EA300 is a two-seat aerobatic monoplane capable of Unlimited category competition. It was designed in 1987 by Walter Extra, a German aerobatic pilot, and built by Extra Flugzeugbau. Design and development Design of the ...
LE have a Siemens SP260D motor weighing 50 kg, with a kWh battery pack, for an aircraft weight of 1,000 kg. It replaces a 235 kW (315 hp)
Lycoming AEIO-580 The Lycoming IO-580 engine is a horizontally opposed, six-cylinder aircraft engine featuring three cylinders per side, manufactured by Lycoming Engines. There is no carburetted version of the engine, which would have been designated O-580 a ...
piston engine weighing 202 kg. The piston-engine Extra 330 empty weight is 677 kg, kg without the engine. The Lycoming engine has a fuel consumption of per hour when outputting , or kg/kWh: it needs kg of fuel to output the same 37.2 kWh. Besides the motor itself, an aircraft weight is hampered by the necessary energy reserves: a 19-seat aircraft needs the mandatory IFR reserves of 5% route contingency, the flight to a 100 nmi alternate plus 30 minutes of holding before landing – 308 kg of fuel for a turboprop, or 4,300 kg of 250 Wh/kg batteries, similar to a current 19-seater empty weight. An electric propulsion system also includes a
power inverter A power inverter, inverter or invertor is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC). The resulting AC frequency obtained depends on the particular device employed. Inverters do the opp ...
, while fuel engines have a fuel system themselves. The experimental
magniX magniX is an electric motor manufacturer for electric aircraft, wholly owned by Singapore investor Clermont Group. The company is headquartered in Everett, Washington, United States. History The company was founded in 2009 in Australia to resea ...
magni500 electric motor weighs , while the certified
Pratt & Whitney Canada PT6 The Pratt & Whitney Canada PT6 is a turboprop aircraft engine produced by Pratt & Whitney Canada. Its design was started in 1958, it first ran in February 1960, first flew on 30 May 1961, entered service in 1964 and has been continuously upda ...
A-114 weighs , both powering the
Cessna 208 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 Federal Aviation Administration, FAA ...
. The increase in power, combined with Supplemental Type Certificate (STC) modifications can offset the weight of the batteries by increasing the airplane's gross operating weight, including the landing weight. Aircraft that use fossil fuels are lighter when they land, which allows the structure to be lighter. With a battery powered aircraft, the weight remains the same, and so may require reinforcement.


Hybrid power

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 electr ...
is an
aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
with a
hybrid electric A hybrid electric vehicle (HEV) is a type of hybrid vehicle that combines a conventional internal combustion engine (ICE) system with an Electric motor, electric propulsion system (hybrid vehicle drivetrain). The presence of the electric powertr ...
powertrain. It typically takes off and lands under clean and quiet electric power, and cruises under conventional piston or jet engine power. This makes long flights practical, while reducing their carbon footprint. By May 2018, there were over 30 projects, and
short-haul In aviation, the flight length refers to the distance of a flight. Commercial flights are often categorized into long-, medium- or short-haul by commercial airlines based on flight length, although there is no international standard definition and ...
hybrid-electric airliners were envisioned from 2032. The most advanced are the Zunum Aero 10-seater, the
Airbus E-Fan X The Airbus/Rolls-Royce/Siemens E-Fan X was a hybrid electric aircraft demonstrator being developed by a partnership of Airbus, Rolls-Royce plc and Siemens. Announced on 28 November 2017, it followed previous electric flight demonstrators towards ...
demonstrator,
AirbusRolls-RoyceSiemens
the VoltAero Cassio, UTC is modifying a
Bombardier Dash 8 The De Havilland Canada DHC-8, commonly known as the Dash 8, is a series of turboprop-powered regional airliners, introduced by de Havilland Canada (DHC) in 1984. DHC was later bought by Boeing in 1988, then by Bombardier in 1992; then by ...
, while the Ampaire Electric EEL prototype first flew on 6 June 2019.


Magnetohydrodynamics

In November 2018,
MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
engineers achieved the first free flight with a model aircraft having no moving parts, the EAD Airframe Version 2. It is propelled by creating an ion wind using
magnetohydrodynamics Magnetohydrodynamics (MHD; also called magneto-fluid dynamics or hydro­magnetics) is the study of the magnetic properties and behaviour of electrically conducting fluids. Examples of such magneto­fluids include plasmas, liquid metals, ...
(MHD). MHD has been used to achieve vertical lift in the past, but only by cabling up the MHD ion generator system to an external power supply.


History

By May 2018 almost 100 electric aircraft were known to be under development. This was up from 70 the previous year and included 60% from startups, 32% from aerospace incumbents, half of them major OEMs and 8% from academic, government organizations and non-aerospace companies, mainly from Europe (45%) and the U.S. (40%). Mostly urban air taxis (50%) and
general aviation General aviation (GA) is defined by the International Civil Aviation Organization (ICAO) as all civil aviation aircraft operations with the exception of commercial air transport or aerial work, which is defined as specialized aviation services ...
aircraft (47%), a majority are battery-powered (73%), while some are hybrid-electric (31%), most of these being larger airliners. By May 2019, the number of known electric aircraft development programmes was closer to 170, with a majority of them aimed at the urban air taxi role. By 2022, about 100 electric aircraft designs were under development worldwide.


Airships

The use of electricity for aircraft propulsion was first experimented with during the development of the
airship An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early ...
in the latter part of the nineteenth century. On 8 October 1883,
Gaston Tissandier Gaston Tissandier (November 21, 1843 – August 30, 1899) was a French chemist, meteorologist, aviator, and editor. He escaped besieged Paris by balloon in September 1870. He founded and edited the scientific magazine ''La Nature'' and wrote se ...
flew the first electrically powered airship. The following year,
Charles Renard Charles Renard (1847–1905) born in Damblain, Vosges, was a French military engineer. Airships After the Franco-Prussian War of 1870-1871 he started work on the design of airships at the French army aeronautical department. Together with A ...
and
Arthur Krebs Arthur Constantin Krebs (16 November 1850 in Vesoul, France – 22 March 1935 in Quimperlé, France) was a French officer and pioneer in automotive engineering. Life Collaborating with Charles Renard, he piloted the first fully controll ...
flew La France with a more powerful motor. Even with the lifting capacity of an airship, the heavy accumulators needed to store the electricity severely limited the speed and range of such early airships. Fully electric airships are expected to be available again by the 2030s.


Unmanned aircraft

In 1909, an electric free flight model was claimed to have been flown eight minutes, but this claim has been disputed by the builder of the first recorded electric Radio-Controlled model aircraft flight in 1957. Power density for electric flight was problematic even for small models. NASA's Pathfinder, Pathfinder Plus,
Centurion A centurion (; la, centurio , . la, centuriones, label=none; grc-gre, κεντυρίων, kentyríōn, or ) was a position in the Roman army during classical antiquity, nominally the commander of a century (), a military unit of around 80 ...
, and
Helios In ancient Greek religion and Greek mythology, mythology, Helios (; grc, , , Sun; Homeric Greek: ) is the deity, god and personification of the Sun (Solar deity). His name is also Latinized as Helius, and he is often given the epithets Hyper ...
were a series of solar and fuel cell system–powered
unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
s (UAVs) developed by AeroVironment, Inc. from 1983 until 2003 under
NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...
's Environmental Research Aircraft and Sensor Technology program. On September 11, 1995, Pathfinder set an unofficial altitude record for solar-powered aircraft of during a 12-hour flight from
NASA Dryden The NASA Neil A. Armstrong Flight Research Center (AFRC) is an aeronautical research center operated by NASA. Its primary campus is located inside Edwards Air Force Base in California and is considered NASA's premier site for aeronautical rese ...
. After further modifications, the aircraft was moved to the
U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...
's
Pacific Missile Range Facility The Pacific Missile Range Facility, Barking Sands is a U.S. naval facility and airport located five nautical miles (9 km) northwest of the central business district of Kekaha, in Kauai County, Hawaii, United States. PMRF is the world's larg ...
(PMRF) on the Hawaiian island of
Kauai Kauai, () anglicized as Kauai ( ), is geologically the second-oldest of the main Hawaiian Islands (after Niʻihau). With an area of 562.3 square miles (1,456.4 km2), it is the fourth-largest of these islands and the 21st largest island ...
. On July 7, 1997, Pathfinder raised the altitude record for solar–powered aircraft to , which was also the record for propeller–driven aircraft. On August 6, 1998, Pathfinder Plus raised the national altitude record to for solar-powered and propeller-driven aircraft. On August 14, 2001, Helios set an altitude record of – the record for FAI class U (experimental/new technologies), and FAI class U-1.d (remotely controlled UAV with a mass between ) as well as the altitude record for propeller–driven aircraft. On June 26, 2003, the Helios prototype broke up and fell into the Pacific Ocean off Hawaii after the aircraft encountered turbulence, ending the program. In 2005,
Alan Cocconi AC Propulsion is a San Dimas, California, USA company founded in 1992 by Alan Cocconi, Wally Rippel, and Paul Carosa, that specializes in alternating current-based drivetrain systems for electric vehicles. It offers AC-induction traction motors ...
of
AC Propulsion AC Propulsion is a San Dimas, California, USA company founded in 1992 by Alan Cocconi, Wally Rippel, and Paul Carosa, that specializes in alternating current-based drivetrain systems for electric vehicles. It offers AC-induction traction motors ...
flew, with the assistance of several other pilots, an unmanned airplane named "SoLong" for 48 hours non-stop, propelled entirely by solar energy. This was the first such around-the-clock flight, on energy stored in the batteries mounted on the aircraft. The
QinetiQ Zephyr The Airbus Zephyr is a series of lightweight solar-powered unmanned aerial vehicles (UAV). The latest model is a high-altitude platform station capable of flying at for months at a time without fueling. It has a wingspan of and weighs . Deve ...
is a lightweight solar-powered
unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
(UAV). As of 23 July 2010 it holds the endurance record for an unmanned aerial vehicle of over 2 weeks (336 hours). It is of
carbon fiber-reinforced polymer Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
construction, the 2010 version weighing (the 2008 version weighed ) with a
span Span may refer to: Science, technology and engineering * Span (unit), the width of a human hand * Span (engineering), a section between two intermediate supports * Wingspan, the distance between the wingtips of a bird or aircraft * Sorbitan ester ...
of (the 2008 version had a wingspan). During the day it uses sunlight to charge lithium-sulphur batteries, which power the aircraft at night. In July 2010 a Zephyr made a world record UAV endurance flight of 336 hours, 22 minutes and 8 seconds (more than two weeks) and also set an altitude record of for FAI class U-1.c (remotely controlled UAV with a weight between ).


Vertical flight

For a tethered device such as an air observation platform, it is possible to run the power up the tether. In an attempt to create a more practical solution than the clumsy balloons then in use, the Austro-Hungarian
Petróczy-Kármán-Žurovec Petróczy, Kármán and Žurovec were Hungarian and Czech engineers who worked on helicopter development immediately before and during World War I in Budapest. Between them they produced two experimental prototypes, the PKZ-1 and PKZ-2, intende ...
PKZ-1 electric-powered helicopter was flown in 1917. It had a specially-designed continuous-rated electric motor made by
Austro-Daimler Austro-Daimler was an Austro-Hungarian automaker company, from 1899 until 1934. It was a subsidiary of the German ''Daimler-Motoren-Gesellschaft'' (DMG) until 1909. Early history In 1890, Eduard Bierenz was appointed as Austrian retailer. The com ...
and received its power up a cable from a ground-based DC generator. However electric motors were not yet powerful enough for such applications and the motor burned out after only a few flights. In 1964,
William C. Brown William C. Brown (May 22, 1916 – February 3, 1999) was an American electrical engineer who helped to invent the crossed-field amplifier in the 1950s and also pioneered microwave power transmission in the 1960s. Brown received his BSEE fro ...
at
Raytheon Raytheon Technologies Corporation is an American multinational aerospace and defense conglomerate headquartered in Arlington, Virginia. It is one of the largest aerospace and defense manufacturers in the world by revenue and market capitaliza ...
flew a model helicopter that received all of the power needed for flight by
microwave power transmission Wireless power transfer (WPT), wireless power transmission, wireless energy transmission (WET), or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system ...
. The world's first large-scale all-electric
tilt-rotor A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called ''proprotors'') mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a tran ...
was the
AgustaWestland Project Zero The AgustaWestland Project Zero is a hybrid tiltrotor/ Lift fan aircraft. It has been developed by AgustaWestland as a technology demonstrator, and is used to investigate all-electric propulsion and other advanced technologies. It is the world' ...
unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
technology demonstrator, which performed unmanned tethered fights on ground power in June 2011, less than six months after the company gave the official go-ahead. The first free-flying electric helicopter was the Solution F/Chretien Helicopter, developed by Pascal Chretien in Venelles, France. It went from
computer-aided design Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve c ...
concept on September 10, 2010, to first flight in August 2011, in under a year. In September 2016,
Martine Rothblatt Martine Aliana Rothblatt (born October 10, 1954) is an American lawyer, author, entrepreneur, and transgender rights advocate. Rothblatt graduated from University of California, Los Angeles with J.D. and M.B.A. degrees in 1981, then began to wor ...
and Tier1 Engineering successfully tested an electric-powered helicopter. The five minute flight reached an altitude of with a peak speed of . The
Robinson R44 The Robinson R44 is a four-seat light helicopter produced by Robinson Helicopter Company since 1992. Based on the company's two-seat Robinson R22, the R44 features hydraulically assisted flight controls. It was first flown on 31 March 1990 and ...
helicopter was modified with two three-phase permanent magnet synchronous YASA Motors, weighing , plus 11
Lithium polymer batteries A lithium polymer battery, or more correctly lithium-ion polymer battery (abbreviated as LiPo, LIP, Li-poly, lithium-poly and others), is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electro ...
from
Brammo Brammo, Inc. was an American producer of electric traction motors and traction batteries based in Talent, Oregon, United States. Brammo also developed and sold a range of electric motorcycles via the company's website and motorcycle dealers throu ...
weighing . It later flew for 20 minutes in 2016. On December 7, 2018, Tier 1 Engineering flew an electric, battery-powered R44 over at and an altitude of , setting a
Guinness World Record ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a reference book published annually, listing world ...
for the farthest distance. In June 2017, Airbus presented its CityAirbus, an electrically powered
VTOL A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...
aircraft demonstrator. The
multirotor A multirotor or multicopter is a rotorcraft with more than two lift-generating rotors. An advantage of multirotor aircraft is the simpler rotor mechanics required for flight control. Unlike single- and double-rotor helicopters which use complex ...
aircraft is intended to carry four passengers, with a pilot initially and to become self-piloted when regulations allow. Its first unmanned flight was scheduled for the end of 2018 with manned flights planned to follow in 2019.
Type certification A type certificate signifies the airworthiness of a particular category of aircraft, according to its manufacturing design (''type design''). It confirms that the aircraft of a new type intended for serial production, is in compliance with applica ...
and commercial introduction are planned for 2023. Ingenuity, the NASA small uncrewed aerial system (sUAS) which flew on Mars in 2021 to become the first extraterrestrial aircraft, has a single pair of
coaxial rotor Coaxial rotors or coax rotors are a pair of helicopter rotors mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions (contra-rotating). This rotor configuration is a feature of helicopt ...
s. The
Dragonfly A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...
rotorcraft lander should be the second aircraft and rotorcraft to operate on another astronomical object than Earth. It should be flying in the atmosphere of Titan starting around 2034. The VTOL capabilities is incorporated in order to move the lander and its sensors at various locations farther from the landing site.


Experimental demonstrators

On 21 October 1973, the Militky MB-E1, a
Brditschka HB-3 The Brditschka HB-3, HB-21 and HB-23 are a family of motor gliders of unorthodox configuration developed in Austria in the early 1970s. Design and development The unusual design was based on work done by Fritz Raab in Germany in the 1960s. The ...
motor glider converted by Fred Militky and Heino Brditschka, flew for 9 minutes from
Linz Linz ( , ; cs, Linec) is the capital of Upper Austria and third-largest city in Austria. In the north of the country, it is on the Danube south of the Czech border. In 2018, the population was 204,846. In 2009, it was a European Capital of ...
in Austria: the first electric aircraft to fly under its own power with a person on board, powered by Nickel–cadmium batteries (NiCad). NiCad batteries have a higher
energy density In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or . Often only the ''useful'' or extract ...
than lead-acid batteries, needed to power an heavier than air aircraft. Following successful
human-powered flight A human-powered aircraft (HPA) is an aircraft belonging to the class of vehicles known as human-powered transport. Human-powered aircraft have been successfully flown over considerable distances. However, they are still primarily constructed a ...
, a relaunched
Kremer prize The Kremer prizes are a series of monetary awards, established in 1959 by the industrialist Henry Kremer. Royal Aeronautical Society Human Powered Flight Group The Royal Aeronautical Society's "Man Powered Aircraft Group" was formed in 1959 b ...
allowed the crew to store energy before takeoff. In the 1980s several such designs stored electricity generated by pedalling, including the MIT Monarch and the Aerovironment Bionic Bat. The
Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product ...
-led FCD (fuel cell demonstrator) project uses a
Diamond HK-36 Super Dimona The Diamond HK36 Super Dimona is an extensive family of Austrian low-wing, T-tailed, two-seat motor gliders that were designed by Wolf Hoffmann and currently produced by Diamond Aircraft Industries.Said, Bob: ''1983 Sailplane Directory, Soarin ...
motor glider as a research test bed for a hydrogen
fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
powered light airplane. Successful flights took place in February and March 2008. The European Commission has financed many low
TRL TRL or trl may refer to: Arts * Temporary Residence Limited, a record label * ''Total Request Live'', a former MTV show * TRL Awards (''Total Request Live''), an Italian music award Libraries * Tampines Regional Library, a regional library in Ta ...
projects for innovative electric or hybrid propulsion aircraft. The ENFICA-FC is a project of the
European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...
, to study and demonstrate an all-electric aircraft with fuel-cells as the main or auxiliary power system. During the three-year project, a fuel-cell based power system was designed and first flown in a Rapid 200FC ultralight aircraft on 20 May 2010. The first NASA Green Flight Challenge took place in 2011 and was won by a
Pipistrel Taurus G4 The Pipistrel Taurus is a Slovenian self-launched two-seat microlight glider designed and built by Pipistrel.Vandermeullen, Richard: ''2012 Kit Aircraft Buyer's Guide'', Kitplanes, Volume 28, Number 12, December 2011, page 65. Belvoir Publication ...
on 3 October 2011. In 2013
Chip Yates Chip Yates (born February 11, 1971 as William Morrison Yates III) is an American inventor and electrical vehicle pioneer best known for risky record-setting feats in electric vehicles of his own design. He designed and built the record-breaking S ...
demonstrated that the world's fastest electric airplane, a Long ESA, a modified
Rutan Long-EZ The Rutan Model 61 Long-EZ is a tandem 2-seater homebuilt aircraft designed by Burt Rutan's Rutan Aircraft Factory. The Long-EZ has a canard layout, a swept wing with wingtip rudders, and a pusher engine and propeller. The tricycle landing ge ...
, could outperform a gasoline-powered Cessna and other aircraft in a series of trials verified by the
Fédération Aéronautique Internationale The (; FAI; en, World Air Sports Federation) is the world governing body for air sports, and also stewards definitions regarding human spaceflight. It was founded on 14 October 1905, and is headquartered in Lausanne, Switzerland. It maintai ...
. The Long ESA was found to be less expensive, have a higher maximum speed, and higher rate of climb, partly due to the ability of the aircraft to maintain performance at altitude as low air density does not impair engine performance. In 2017,
Siemens Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad. The principal divisions of the corporation are ''Industry'', '' ...
used a modified
Extra EA-300 The Extra Flugzeugbau EA300 is a two-seat aerobatic monoplane capable of Unlimited category competition. It was designed in 1987 by Walter Extra, a German aerobatic pilot, and built by Extra Flugzeugbau. Design and development Design of the E ...
acrobatic airplane, the 330LE, to set two new records: on March 23 at the
Dinslaken Dinslaken is a town in the district of Wesel, in North Rhine-Westphalia, Germany. It is known for its harness racing track, its now closed coal mine in Lohberg and its wealthy neighborhoods ''Hiesfeld'' and ''Eppinghoven''. Geography Dinslaken ...
Schwarze Heide airfield in Germany, the aircraft reached a top speed of around over and the next day, it became the first glider towing electric aircraft.
NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...
developed the X-57 Maxwell to demonstrate technology to reduce fuel use, emissions, and noise. Modified from a
Tecnam P2006T The Tecnam P2006T is an Italian high-winged twin-engined all-metal light aircraft, built by Costruzioni Aeronautiche Tecnam based in Capua, Italy, near Naples. The P2006T received airworthiness certification in the European Union by EASA under C ...
, the X-57 will have 14
electric motor An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...
s driving
propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
s mounted on the wing leading edges. In July 2017,
Scaled Composites Scaled Composites (often called simply Scaled) is an American aerospace company founded by Burt Rutan and currently owned by Northrop Grumman. It is located at the Mojave Air and Space Port in Mojave, California, United States. Founded to develo ...
is modifying a first P2006T by replacing the piston engines with electric motors, to fly early in 2018, then will move the motors to the
wingtips A wing tip (or wingtip) is the part of the wing that is most distant from the fuselage of a fixed-wing aircraft. Because the wing tip shape influences the size and drag of the wingtip vortices, tip design has produced a diversity of sha ...
to increase
propulsive efficiency In aerospace engineering, concerning aircraft, rocket and spacecraft design, overall propulsion system efficiency \eta is the efficiency with which the energy contained in a vehicle's fuel is converted into kinetic energy of the vehicle, to accelera ...
and finally will install the high aspect ratio wing with 12 smaller props. US/UK startup
ZeroAvia ZeroAvia is a British/American hydrogen-electric aircraft developer. The company was founded in 2017 by Valery Miftakhov, who currently serves as the company CEO. ZeroAvia is developing hydrogen-fueled powertrain technology aiming to compete w ...
develops zero-emissions
fuel-cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requi ...
propulsion systems for small aircraft, and tests its HyFlyer in Orkney supported by £2.7 million from the UK government.


Solar aircraft

On April 29, 1979, the
Mauro Solar Riser The Mauro Solar Riser is an American biplane ultralight electric aircraft that was the first crewed aircraft to fly on solar power. It was also only the second solar-powered aircraft to fly, after the uncrewed AstroFlight Sunrise, which had ...
became the first person-carrying, solar-powered aircraft to fly, with photovoltaic cells delivering at 30 volts and charging a small battery, which powered the motor. Following a 1.5-hour charge, the battery could power the aircraft for 3 to 5 minutes to reach a gliding altitude. It followed a successful model test in 1974, as solar cells were developed, at the same period than with NiCad batteries. Under the direction of Freddie To, an architect and member of the
Kremer prize The Kremer prizes are a series of monetary awards, established in 1959 by the industrialist Henry Kremer. Royal Aeronautical Society Human Powered Flight Group The Royal Aeronautical Society's "Man Powered Aircraft Group" was formed in 1959 b ...
committee, the Solar One was designed by David Williams and produced by Solar-Powered Aircraft Developments. A motor-glider type aircraft originally built as a pedal-powered airplane to attempt the Channel crossing, the airplane proved too heavy to be successfully powered by human power and was then converted to solar power, using an electric motor driven by batteries that were charged before flight by a solar cell array on the wing. The maiden flight of Solar One took place at
Lasham Airfield Lasham Airfield is an aerodrome located north-west of Alton in Hampshire, England, in the village of Lasham. It was built in 1942 and was a Royal Air Force Station during the Second World War, many significant operations being flown from it. ...
, Hampshire, on June 13, 1979. The MacCready Gossamer Penguin first flew carrying a pilot in 1980. The
MacCready Solar Challenger The Solar Challenger was a solar-powered electric aircraft designed by Paul MacCready's AeroVironment. The aircraft was designed as an improvement on the Gossamer Penguin, which in turn was a solar-powered variant of the human-powered Gossamer ...
was first flown in 1980, and in 1981 flew 163 miles from Pontoise – Cormeilles Aerodrome, north of
Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
,
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
to Manston Royal Air Force Base in Manston,
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
, staying aloft 5 hours and 23 minutes, with pilot Stephen Ptacek at the controls. The human piloted
Solair Solair I and Solair II are two German-designed electric aircraft. Solair 1 The human piloted Solair I was developed from 1980 by Günther Rochelt - developer of the Musculair human-powered aircraft series - based on a Hans Farner canard design. ...
1, developed by Günther Rochelt, flew in 1983 with notably improved performance. It employed 2499 wing-mounted solar cells. The German solar-powered aircraft "Icaré II" was designed and built by the institute of aircraft design (Institut für Flugzeugbau) of the University of Stuttgart in 1996. The leader of the project and often pilot of the aircraft is Rudolf Voit-Nitschmann, the head of the institute. The design won the Berblinger prize in 1996, the EAA Special Achievement Award in Oshkosh, the Golden Daidalos Medal of the German Aeroclub and the OSTIV-Prize in France in 1997.
Solar Impulse 2 Solar Impulse is a Swiss long-range experimental solar-powered aircraft project, and also the name of the project's two operational aircraft. The privately financed project is led by Swiss engineer and businessman André Borschberg and Swiss p ...
is powered by four electric motors. Energy from solar cells on the wings and horizontal stabilizer is stored in lithium polymer batteries and used to drive propellers. In 2012 the first
Solar Impulse Solar Impulse is a Swiss long-range experimental solar-powered aircraft project, and also the name of the project's two operational aircraft. The privately financed project is led by Swiss engineer and businessman André Borschberg and Swiss ...
made the first intercontinental flight by a solar aircraft, flying from
Madrid Madrid ( , ) is the capital and most populous city of Spain. The city has almost 3.4 million inhabitants and a metropolitan area population of approximately 6.7 million. It is the second-largest city in the European Union (EU), and ...
, Spain to
Rabat Rabat (, also , ; ar, الرِّبَاط, er-Ribât; ber, ⵕⵕⴱⴰⵟ, ṛṛbaṭ) is the capital city of Morocco and the country's seventh largest city with an urban population of approximately 580,000 (2014) and a metropolitan populati ...
, Morocco. Completed in 2014, Solar Impulse 2 carried more solar cells and more powerful motors, among other improvements. In March 2015, the aircraft took off on the first stage of a planned round-the-world trip, flying eastwards from
Abu Dhabi Abu Dhabi (, ; ar, أَبُو ظَبْيٍ ' ) is the capital and second-most populous city (after Dubai) of the United Arab Emirates. It is also the capital of the Emirate of Abu Dhabi and the centre of the Abu Dhabi Metropolitan Area. ...
, United Arab Emirates. Due to battery damage, the craft halted at
Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
, where its batteries were replaced. It resumed the circumnavigation in April 2016 and reached
Seville Seville (; es, Sevilla, ) is the capital and largest city of the Spanish autonomous community of Andalusia and the province of Seville. It is situated on the lower reaches of the River Guadalquivir, in the southwest of the Iberian Peninsula ...
, Spain, in June 2016. The following month it returned to Abu Dhabi, completing its circumnavigation of the world.


General aviation

An application is as a sustaining motor or even a self-launching motor for gliders. The most common system is the
front electric sustainer Front electric sustainer (FES) is a propulsion system for gliders that uses an electric motor powered by batteries and a foldable propeller. It is produced by LZ Design d.o.o. in Logatec, Slovenia. The system uses a 22 kW compact outrunner ...
, which is used in over 240 gliders. The short range is not a problem as the motor is used only briefly, either to launch or to avoid an outlanding (an unplanned landing while soaring). The first commercially available, non-certified production electric aircraft, the
Alisport Silent Club __NOTOC__ The Silent Club is a single seater sailplane of Italian manufacture. It is of the FAI type DU Class glider. It is sold by Alisport ready-to-fly or kit-built as pure glider or self-launching glider. The self-launching version is fitted w ...
self-launching
glider Glider may refer to: Aircraft and transport Aircraft * Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight ** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...
, flew in 1997. It is optionally driven by a DC electric motor running on of batteries that store of energy. The first certificate of airworthiness for an electric powered aircraft was granted to the Lange Antares 20E in 2003. Also an electric, self-launching glider/sailplane, with a DC/DC brushless motor and
lithium-ion batteries A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also se ...
, it can climb up to with fully charged cells. The first flight was in 2003. In 2011 the aircraft won the 2011 Berblinger competition. In late 2000s Chinese manufacturer of radio-controlled models Yuneec International developed and tested several battery-powered manned fixed-wing aircraft, including E430, the first electric aircraft designed to be serially produced, but failed to commercialize them (only prototypes were built) and in mid-2010s turned to the lucrative consumer drone market. The Taurus Electro was the first two-seat electric aircraft to have ever flown, while the Taurus Electro G2 is the production version, that was introduced in 2011. Powered by a electric motor and lithium batteries for self-launching to an altitude of , after which the engine is retracted and the aircraft then soars as a sailplane. It is the first two-seat electric aircraft to have achieved series production. As pilot training emphasises short flights, several companies make, or have demonstrated, light aircraft suitable for initial flight training. The
Airbus E-Fan The Airbus E-Fan is a prototype two-seater electric aircraft that was under development by Airbus. It was flown in front of the world press at the Farnborough Airshow in the United Kingdom in July 2014. The target market was intended to be pil ...
was aimed at flight training but the project was cancelled.
Pipistrel Pipistrel d.o.o Ajdovščina is a Slovenian light aircraft manufacturer established in 1989Or 1989... --> by Ivo Boscarol and based in Ajdovščina. Its facilities are located in Ajdovščina, Slovenia, and near the town of Gorizia, Italy. By ...
makes light sport electric aircraft such as the
Pipistrel WATTsUP The Pipistrel WATTsUP is an electric aircraft proof-of-concept trainer design that was built in Slovenia by Pipistrel.Tacke, Willi; Marino Boric; et al: ''World Directory of Light Aviation 2015-16'', page 73. Flying Pages Europe SARL, 2015. Th ...
, a prototype of the Pipistrel Alpha Electro. The advantage of electric aircraft for flight training is the lower cost of electrical energy compared to aviation fuel. Noise and exhaust emissions are also reduced compared with combustion engines. The Bye Aerospace eFlyer 2 (formerly the Sun Flyer 2) 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. On 10 June 2020, the
Velis Electro The Pipistrel Velis Electro is a Slovenian light aircraft, designed and produced by Pipistrel of Ajdovščina. The aircraft was EASA CS-LSA fully electric type certified in June 2020 and it is intended primarily for the training aircraft role, ...
variant of the two-seat
Pipistrel Virus The Pipistrel Virus is a two-seat, single engine light aircraft, manufactured by Pipistrel in Slovenia and Italy, and sold as an ultralight, homebuilt kit, or light-sport aircraft.Vandermeullen, Richard: ''2012 Kit Aircraft Buyer's Guide'', Kitpl ...
was the first electric aircraft to secure
type certification A type certificate signifies the airworthiness of a particular category of aircraft, according to its manufacturing design (''type design''). It confirms that the aircraft of a new type intended for serial production, is in compliance with applica ...
, from the
EASA The European Union Aviation Safety Agency (EASA) is an agency of the European Union (EU) with responsibility for civil aviation safety. It carries out certification, regulation and standardisation and also performs investigation and monitori ...
. Powered by a 76 hp (58 kW) electric motor developed with
Emrax Emrax d.o.o is a Slovenian electric aircraft engine manufacturer founded by Roman Sušnik and based in Kamnik. The company specializes in the design and manufacture of electric motors for light aircraft.Bayerl, Robby; Martin Berkemeier; et al: '' ...
, it offers a payload of , a cruise speed of 90 kn (170 km/h), and a 50 min endurance. Pipistrel plans to deliver over 30 examples in 2020, to be operated as a
trainer aircraft A trainer is a class of aircraft designed specifically to facilitate flight training of pilots and aircrews. The use of a dedicated trainer aircraft with additional safety features—such as tandem flight controls, forgiving flight characteristi ...
. On 12 October 2021, Diamond Aircraft announced the development of the e
DA40 The Diamond DA40 Diamond Star is an Austrian four-seat, single-engine, light aircraft constructed from composite materials. Built in both Austria and Canada, it was developed as a four-seat version of the earlier DA20 by Diamond Aircraft ...
, targeting a 2022 first flight and a 2023 EASA/FAA Part 23 certification, tailored to the flight training market. The four-seat aircraft should be able to fly for up to 90 minutes, with 40% lower operating costs than piston power.


Airliner projects

The NASA Electric Aircraft Testbed (NEAT) is a
NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...
reconfigurable
testbed A testbed (also spelled test bed) is a platform for conducting rigorous, transparent, and replicable testing of scientific theories, computational tools, and new technologies. The term is used across many disciplines to describe experimental rese ...
in
Plum Brook Station NASA John H. Glenn Research Center at Lewis Field is a NASA center within the cities of Brook Park and Cleveland between Cleveland Hopkins International Airport and the Rocky River Reservation of Cleveland Metroparks, with a subsidiary facilit ...
, Ohio, used to design, develop, assemble and test electric aircraft power systems, from a small, one or two person aircraft up to
airliner An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ...
s. NASA research agreements (NRA) are granted to develop electric-propulsion components. They will be completed in 2019 and the internal NASA work by 2020, then they will be assembled in a megawatt-scale drive system to be tested in the narrowbody-sized NEAT. In September 2017, UK budget carrier
EasyJet EasyJet plc (styled as easyJet) is a British multinational low-cost airline group headquartered at London Luton Airport. It operates domestic and international scheduled services on 927 routes in more than 34 countries via its affiliate airli ...
announced it was developing an electric 180-seater for 2027 with Wright Electric. Founded in 2016, US Wright Electric built a two-seat proof-of-concept with 272 kg (600 lb) of batteries, and believes they can be scaled up with substantially lighter new battery chemistries. A 291 nmi (540 km) range would suffice for 20% of Easyjet passengers. Wright Electric will then develop a 10-seater, eventually an at least 120 passengers single aisle, short haul airliner and targets 50% lower noise and 10% lower costs. Jeffrey Engler, CEO of Wright Electric, estimates that commercially viable electric planes will lead to around a 30% reduction in energy costs. On March 19, 2018,
Israel Aerospace Industries Israel Aerospace Industries (Hebrew: התעשייה האווירית לישראל ''ha-ta'asiya ha-avirit le-yisra'el'') or IAI (תע"א) is Israel's major aerospace and aviation manufacturer, producing aerial and astronautic systems for both mi ...
announced it plans to develop a short-haul electric airliner, building on its small UAS electric power systems experience. It could develop it in-house, or with a startup like Israeli Eviation, U.S. Zunum Aero or Wright Electric. Australia-based
MagniX magniX is an electric motor manufacturer for electric aircraft, wholly owned by Singapore investor Clermont Group. The company is headquartered in Everett, Washington, United States. History The company was founded in 2009 in Australia to resea ...
has developed an electric
Cessna 208 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 Federal Aviation Administration, FAA ...
with a motor for flight durations up to an hour. The company's Magni5 electric motor produces continuously , peak at 2,500 rpm at 95% efficiency with a 53 kg (117 lb) dry mass, a 5 kW/kg power density, competing with the , Siemens SP260D for the Extra 330LE. By September 2018, a electric motor with a propeller had been tested on a Cessna iron bird. The Caravan was expected to fly by the fall of 2019 and by 2022 MagniX estimates electric aircraft will have ranges of by 2024. The motor ran on a test
dynamometer A dynamometer or "dyno" for short, is a device for simultaneously measuring the torque and rotational speed (RPM) of an engine, motor or other rotating prime mover so that its instantaneous power may be calculated, and usually displayed by the ...
for 1,000 hours. The iron bird is a Caravan forward fuselage used as a test bed, with the original
Pratt & Whitney Canada PT6 The Pratt & Whitney Canada PT6 is a turboprop aircraft engine produced by Pratt & Whitney Canada. Its design was started in 1958, it first ran in February 1960, first flew on 30 May 1961, entered service in 1964 and has been continuously upda ...
turboprop engine replaced by an electric motor, inverter and a liquid-cooling system, including radiators, driving a
Cessna 206 The Cessna 205, 206, and 207, known primarily as the Stationair (and marketed variously as the Super Skywagon, Skywagon and Super Skylane) are a family of single-engined, general aviation aircraft with fixed landing gear, used in commercial air ...
propeller. The production motor will produce at 1,900 rpm, down from the test motor's 2,500 rpm, allowing the installation without a reduction gearbox. On 28 May 2020, the MagniX electric-powered nine-passenger
Cessna 208B 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 Cargoma ...
''eCaravan'' flew on electric power, towards commercial operation certification. A 560-kW (750-hp) MagniX electric motor was installed in a
de Havilland Canada DHC-2 Beaver The de Havilland Canada DHC-2 Beaver is a single-engined high-wing propeller-driven short takeoff and landing (STOL) aircraft developed and manufactured by de Havilland Canada. It has been primarily operated as a bush plane and has been used ...
seaplane.
Harbour Air A harbor (American English), harbour (British English; see spelling differences), or haven is a sheltered body of water where ships, boats, and barges can be docked. The term ''harbor'' is often used interchangeably with ''port'', which is ...
, based in
British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
, was hoping to introduce the aircraft in commercial service in 2021, for trips under 30 minutes initially, until range increases as better batteries are introduced. On December 10, 2019, it made its first flight of four minutes duration from the
Fraser River The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Blackrock Mountain in the Rocky Mountains and flowing for , into the Strait of Georgia just south of the City of Vancouver. The river's annual d ...
near
Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...
. The normally-fitted
Pratt & Whitney R-985 Wasp Junior The Pratt & Whitney R-985 Wasp Junior is a series of nine-cylinder, air-cooled, radial aircraft engines built by the Pratt & Whitney Aircraft Company from the 1930s to the 1950s. These engines have a displacement of ; initial versions produced , ...
piston engine of the six-passenger Beaver was replaced by a 135 kg (297 lb) magni500, with swappable batteries, allowing 30 minute flights with a 30-minute reserve. By April 2022, flight testing of a certifiable version through a STC was delayed until late 2023, to carry four passengers and a pilot on 30 minute flights with a 30 minute reserve. Magnix is seeking
FAA The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...
certification for its 640 kW (850shp) Magni650 aircraft engine, while battery provider H55 (a spin-off from
Solar Impulse Solar Impulse is a Swiss long-range experimental solar-powered aircraft project, and also the name of the project's two operational aircraft. The privately financed project is led by Swiss engineer and businessman André Borschberg and Swiss ...
) is pursuing
EASA The European Union Aviation Safety Agency (EASA) is an agency of the European Union (EU) with responsibility for civil aviation safety. It carries out certification, regulation and standardisation and also performs investigation and monitori ...
approval. A demonstrator for the German Scylax E10 10-seater should fly in 2022. It should be used by
FLN Frisia Luftverkehr FLN FRISIA-Luftverkehr GmbH Norddeich, usually shortened to FLN, is a small airline from Germany based in Norden, Lower Saxony, which was founded on 14 June 1969. Destinations As of November 2020, FLN operates scheduled flights between Nordde ...
to connect
East Frisian islands The East Frisian Islands (German: ''Ostfriesische Inseln'', West Frisian: ''Eastfryske eilannen'', stq, Aastefräiske Ailounds) are a chain of islands in the North Sea, off the coast of East Frisia in Lower Saxony, Germany. The islands extend fo ...
with its range and 300 m (980 ft)
short takeoff and landing A short takeoff and landing (STOL) aircraft is a conventional fixed-wing aircraft that has short runway requirements for takeoff and landing. Many STOL-designed aircraft also feature various arrangements for use on airstrips with harsh condition ...
distance. On 23 September 2020,
Gothenburg Gothenburg (; abbreviated Gbg; sv, Göteborg ) is the second-largest city in Sweden, fifth-largest in the Nordic countries, and capital of the Västra Götaland County. It is situated by the Kattegat, on the west coast of Sweden, and has ...
-based Heart Aerospace presented its ES-19 design, a 19-seat all-electric commercial aircraft planned to fly by mid-2026. With a conventional aluminium airframe and wing, its planned range is 400 km (222 nmi) and expects to operate from runways as short as 800 m (2,640 ft). Initially targeting airlines operating in the
Nordic countries The Nordic countries (also known as the Nordics or ''Norden''; literal translation, lit. 'the North') are a geographical and cultural region in Northern Europe and the Atlantic Ocean, North Atlantic. It includes the sovereign states of Denmar ...
, Heart has received "expressions of interest" for 147 ES-19 aircraft worth about €1.1 billion or US$1.3 billion (€ million or $ million each) from at least eight airlines. Backed by Swedish venture capitalist
EQT Ventures EQT Ventures is the venture capital business of Sweden, Swedish Investment management, investment manager EQT Partners, EQT AB Group. In May 2016, EQT Ventures announced its first €566m fund that makes minority equity investments in European an ...
, Nordic governments and the
European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
, Heart was initially funded by the Swedish innovation agency
Vinnova Vinnova is the Swedish government agency that administers state funding for research and development. The agency's mission as defined by the government is to promote development of efficient and innovative Swedish systems within the areas of tech ...
and is an alumnus of Silicon Valley start-up accelerator
Y Combinator Y Combinator (YC) is an American technology startup accelerator launched in March 2005. It has been used to launch more than 3,000 companies, including Airbnb, Coinbase, Cruise, DoorDash, Dropbox, Instacart, Quora, PagerDuty, Reddit, Str ...
. On 22 March 2021,
Toulouse Toulouse ( , ; oc, Tolosa ) is the prefecture of the French department of Haute-Garonne and of the larger region of Occitania. The city is on the banks of the River Garonne, from the Mediterranean Sea, from the Atlantic Ocean and from Par ...
-based Aura Aero announced the development of its ERA (Electric Regional Aircraft), a 19-passenger electric aircraft, planned to be certified in 2026.


Shipments

The following table summarizes electric aircraft shipments worldwide by manufacturer.


List of battery-electric aircraft


See also

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Electric boat An electric boat is a powered watercraft driven by electric motors, which are powered by either on-board battery packs, solar panels or generators. While a significant majority of water vessels are powered by diesel engines, with sail pow ...
*
Electric vehicle An electric vehicle (EV) is a vehicle that uses one or more electric motors for propulsion. It can be powered by a collector system, with electricity from extravehicular sources, or it can be powered autonomously by a battery (sometimes cha ...
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Solar energy Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essenti ...
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VTOL A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...


References


External links

* {{DEFAULTSORT:Electric Aircraft Energy conservation
Aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
Renewable energy technology Aviation and the environment