Wikipedia

Electric aircraft: Difference between revisions

Browse history interactively
← Previous edit
Content deleted Content added
VisualWikitext
→‎Solar aircraft: {{See also|Solar aircraft}}
GreenC bot (talk | contribs)
Bots
2,403,116 edits
Rescued 1 archive link. Wayback Medic 2.5 per WP:URLREQ#timesonline.co.uk
 
(29 intermediate revisions by 21 users not shown)
Line 17:
[[Model aircraft#Electric power|Electrically powered model aircraft]] have been flown at least since 1957, preceding the small [[unmanned aerial vehicle]]s (UAV) or drones used today. Small [[Unmanned aircraft system|UAS]] could be used for parcel deliveries, and larger ones for long-endurance applications: aerial imagery, surveillance, telecommunications.
<!--Experimental demonstrators-->
The first crewed free flight by an electrically powered [[aeroplane]], the [[Militky MB-E1|MB-E1]], was made in 1973, and most crewed electric aircraft today are still only experimental prototypes. The world's first serially produced self-launching, manned electric aircraft with [[European Union Aviation Safety Agency|EASA]] type certification since 2006<ref>{{Cite web |title=EASA Aircraft Type Certificate Data Sheet – EASA-TCDS.A.092 Issue 4 -– Lange E1 Antares |url=https://www.easa.europa.eu/en/downloads/7342/en |url-status=live |access-date=2024-01-03 |format=PDF}}</ref> and a [[patent]]ed wing-integrated battery system,<ref>{{Cite web |date=2011-05-27 |title=Register information Patent DE file number : 195 12 816.8 |url=https://register.dpma.de/DPMAregister/pat/register?lang=en&fromSprachWechselLink |access-date=2024-01-03 |website=German Patent & Trade Mark Office}}</ref> the [[Lange Antares|Lange E1 Antares]], completed its maiden flight in 1999; since 2004, more than 100 aircraft of this type have been delivered, totalling more than 165,000 electric flight hours to date (until 2022).<ref>{{Cite web |title="The most electric flying hours in the world" -– “We"We have more electric flight hours than all other companies and all other aircraft in the world combined.”" -Axel Lange, CEO Lange Aviation in conversation with Prof. Dr. Otto Künzel at the Berblingen Flight Forum 2022 |date=31 March 2022 |url=https://www.lange-aviation.com/en/about-us/ |url-status=live |access-date=2024-01-03}}</ref>
<!--Solar aircraft-->
Between 2015 and 2016, [[Solar Impulse 2]] completed a circumnavigation of the Earth using solar power.
Line 24:
<!--Airliner projects-->
Electric [[commercial airliner]]s could lower operating costs.<ref name=ACRP-2022/>{{rp|1–7}}
 
==Environmental effects of aviation==
{{main|Environmental effects of aviation}}
The [[environmental effects of aviation]] on [[climate change]] 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 {{CO2}} emissions, and its emissions of air transportation altogether increased by 32% between 2013 and 2018.<ref name=AirInt>{{cite web|last=Broadbent|first=Mark|title=Do airlines dream of electric fleets?|url=https://www.airinternational.com/article/do-airlines-dream-electric-fleets|work=www.airinternational.com|publisher=Key Publishing|location=Lincs, UK|date=13 February 2020|access-date=17 April 2021}}</ref> While estimating aviation's non-{{CO2}} effects on climate change is complex, [[NOx]] and [[contrail]]s could increase this responsibility to 3.5%.<ref>{{Cite web|title=Aviation is responsible for 3.5 percent of climate change, study finds|url=https://research.noaa.gov/article/ArtMID/587/ArticleID/2667/Aviation-is-responsible-for-35-percent-of-climate-change-study-finds|date=2020-09-03|work=NOAA Research}}</ref> Other benefits are the potential for noise reduction, in an industry with a severe [[Aircraft noise pollution|noise pollution]] and [[noise abatement|abatement]] problem.<ref name=sustainableskies12dec2019/>
 
==Offboard power supply==
Mechanisms for supplying the necessary electricity without storing all of it onboard include:
*[[Solar cell]]s convert sunlight directly into electricity using [[photovoltaic]] materials.
*[[Microwave]] energy that is [[Power beaming|beamed]] from a remote transmitter.
*[[Power cable]]s connected to a ground-based electrical supply.
 
===Solar cells===
[[File:Pathfinder being prepared for flight - GPN-2000-000238.jpg|thumb|[[Solar panel]]s on the [[NASA Pathfinder]] wing's upper surface]]
 
A [[solar cell]] 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 {{cvt|150|-|200|W/m2}} in direct sunlight.<ref name=Catlow>{{cite web|last=Catlow|first=Amy |title=How Much Electricity Can I Generate with Solar Panels?|url=https://www.theecoexperts.co.uk/solar-panels/how-much-electricity|website=www.theecoexperts.co.uk|access-date=18 April 2021|date=26 May 2020}}</ref> 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.<ref name=Murphy215>{{cite book|last=Murphy|first=Thomas W. Jr.|title=Energy and Human Ambitions on a Finite Planet|url=https://escholarship.org/uc/item/9js5291m|publisher=eScholarship|date=11 March 2021|isbn=978-0578867175|page=215}}</ref>
 
Between 2010 and 2020, solar power modules have declined in cost by 90% and continue to drop by 13–15% per year.<ref name=IRENA>{{cite book|last1=Taylor|first1=Michael|last2=Ralon|first2=Pablo|last3=Anuta|first3=Harold|last4=Al-Zoghoul |first4=Sonia|title=Renewable Power Generation Costs in 2019|publisher=[[International Renewable Energy Agency]] (IRENA)|location=Abu Dhabi|isbn=978-9292602444|year=2020|page=21|url=https://www.irena.org/publications/2020/Jun/Renewable-Power-Costs-in-2019|access-date=18 April 2021}}</ref> [[Solar cell efficiency]] 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.<ref name=PV>{{cite web|last=Han|first=Amos|title=Efficiency Of Solar PV, Then, Now And Future|url=https://sites.lafayette.edu/egrs352-sp14-pv/technology/history-of-pv-technology/|access-date=18 April 2021|work=lafayette.edu}}</ref>
 
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.<ref name=cold>{{cite web|last=Murmson|first=Serm|title=Does a Solar Panel Stop Working When It Gets Too Cold?|url=https://sciencing.com/solar-panel-stop-working-gets-cold-8161.html|access-date=18 April 2021|work=sciencing.com|date=April 24, 2017}}</ref><ref name=Altitude>{{cite web|last=Luntz|first=Stephen|title=How Solar At High Altitudes Could Power Entire Countries, Even In Winter|url=https://www.iflscience.com/technology/how-solar-at-high-altitudes-could-power-entire-countries-even-in-winter/all/|access-date=18 April 2021|date=8 January 2019}}</ref> The drop in the dry-air temperature as altitude increases, called the [[Lapse rate|environmental lapse rate (ELR)]], averages 6.49&nbsp;°C/km<ref name="ICAO 1993">{{cite book|publisher=[[International Civil Aviation Organization]]|title=Manual of the ICAO Standard Atmosphere (extended to 80 km (262,500 ft))|id=Doc 7488-CD|edition=Third|year=1993|isbn=9789291940042}}</ref> (memorized in pilot training as 1.98&nbsp;°C/1,000&nbsp;ft or 3.56&nbsp;°F/1,000&nbsp;feet) so that temperature for a typical airliner's cruising altitude of around {{cvt|35000|ft}} 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]] of electromagnetic energy such as [[microwave]]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.<ref name="Power Beaming">{{Cite web|url=http://www.dfrc.nasa.gov/gallery/Photo/Power-Beaming/index.html|archive-url=https://web.archive.org/web/20130217082723/http://www.dfrc.nasa.gov/gallery/Photo/Power-Beaming/index.html|url-status=dead|title=Power Beaming|archive-date=17 February 2013|access-date=20 August 2019}}</ref>
 
===External power cables===
For powered vehicles replacing tethered [[aerostat]]s, an electrical [[power cable]] can be connected to a ground-based supply, such as an electric generator or the local [[power grid]]. At low altitudes this avoids having to lift batteries, and was used by the experimental [[Petróczy-Kármán-Žurovec|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:
*[[electric battery|Batteries]] which use a chemical reaction to generate electricity which is reversed when recharged.
*[[Fuel cell]]s consume fuel and an oxidizer in a chemical reaction to generate electricity, they need to be refueled, typically with hydrogen.
 
===Batteries===
[[File:Tier1 Engineering - Electric Helicopter Batteries.jpg|thumb|[[Electric batteries|Batteries]] for the Tier1 Engineering electric [[Robinson R44]]]]
 
Batteries are the most common onboard [[energy carrier|energy storage]] 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]]. 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.<ref>{{cite book |last1=Boggio-Dandry |first1=Andrew |title=2018 9th IEEE Annual Ubiquitous Computing, Electronics & Mobile Communication Conference (UEMCON) |chapter=Perpetual Flight for UAV Drone Swarms Using Continuous Energy Replenishment |journal=IEEE |date=2018 |volume=2018 9th IEEE Annual Ubiquitous Computing, Electronics & Mobile Communication Conference (UEMCON) |pages=478–484 |doi=10.1109/UEMCON.2018.8796684 |isbn=978-1-5386-7693-6 |s2cid=201069705 |chapter-url=https://ieeexplore.ieee.org/document/8796684}}</ref> 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.<ref>{{cite journal |last1=González-Jorge |first1=H. |title=nmanned aerial systems for civil applications: A review |journal=Drones |date=2017|volume=1 |page=2 |doi=10.3390/drones1010002 |doi-access=free }}</ref><ref name=Fredericks20nov2018>{{cite journal |last1=Fredericks |first1=W. |title=Performance Metrics Required of Next-Generation Batteries to Electrify Vertical Takeoff and Landing (VTOL) Aircraft |journal=ACS Energy Letters |date= November 20, 2018 |volume=3 |issue=12 |pages=2989–2994 |doi=10.1021/acsenergylett.8b02195 |s2cid=115445306 |doi-access=free }}</ref> 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&nbsp;kg) and average energy density (150 Wh/kg) could travel a range of ~80&nbsp;mi with one passenger, ~60&nbsp;mi with two, and less than ~30&nbsp;mi with three.<ref name=Fredericks20nov2018/>
 
In 2017 the power available from batteries was estimated at 170 Wh/kg, 145 Wh/kg at the shaft including the system efficiency, while a [[gas turbine]] extracted 6,545 Wh/kg of shaft power from an 11,900 Wh/kg fuel.<ref>{{cite news |url= https://leehamnews.com/2017/06/30/bjorns-corner-electric-aircraft/ |title= Bjorn's Corner: Electric aircraft |author= Bjorn Fehrm |date= June 30, 2017 |work= Leeham}}</ref> In 2018 [[Lithium-ion batteries]] including packaging and accessories were estimated to give 160 Wh/kg while aviation fuel gave 12,500 Wh/kg.<ref name=IEEE1jun2018>{{cite news |url= https://spectrum.ieee.org/aerospace/aviation/hybrid-electric-airliners-will-cut-emissionsand-noise |date= 1 Jun 2018 |title= Hybrid Electric Airliners Will Cut Emissions—and Noise |author= Philip E. Ross |work= [[IEEE Spectrum]]}}</ref> In 2018 the [[specific energy]] of [[electricity storage]] was still only 2% of [[aviation fuel]].<ref>{{cite news |url= https://www.flightglobal.com/news/articles/ebace-cessna-short-circuits-talk-of-electric-powere-448953/ |title= Cessna short-circuits talk of electric-powered aircraft |date= 28 May 2018 |author= Stephen Trimble |work= Flightglobal}}</ref> This 1:50 ratio makes electric propulsion impractical for long-range aircraft, as a {{cvt|500|nmi|km}} mission for an all-electric, 12-passenger aircraft would require a six-fold increase in battery power density.<ref name=MRO10jan2019>{{cite news |last=Seidenman|first=Paul|url=https://www.mro-network.com/engines-engine-systems/how-batteries-need-develop-match-jet-fuel|archive-url=https://web.archive.org/web/20190419070640/https://www.mro-network.com/engines-engine-systems/how-batteries-need-develop-match-jet-fuel|url-status=dead|archive-date=April 19, 2019|title=How Batteries Need To Develop To Match Jet Fuel|date=Jan 10, 2019|work=Aviation Week Network}}</ref> That said, battery-electric motors have a higher efficiency (~90%) than most jet engines (~50%), which can be further exploited through emerging battery chemistries.<ref name=Schäfer10dec2018>{{cite journal |last1=Schäfer |first1=A. |title=Technological, economic and environmental prospects of all-electric aircraft |journal=Nature Energy |year=2019 |volume=4 |issue=2 |pages=160–166 |doi=10.1038/s41560-018-0294-x |hdl=1721.1/126682 |s2cid=134741946 |url= https://www.nature.com/articles/s41560-018-0294-x |url-access= subscription|hdl-access=free }}</ref>
 
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.<ref>{{cite web|last1=Lineberger|first1=R.|title=Change is in the air: The elevated future of mobility: What's next on the horizon?|url=https://www2.deloitte.com/us/en/insights/focus/future-of-mobility/evtol-elevated-future-of-mobility-summary.html|url-status=live|date= 3 June 2019|website=Deloitte|archive-url=https://web.archive.org/web/20191026093211/https://www2.deloitte.com/us/en/insights/focus/future-of-mobility/evtol-elevated-future-of-mobility-summary.html |archive-date=2019-10-26 }}</ref><ref>{{cite journal |last1=Alnaqeb |first1=A. |title=Masters Thesis: Online prediction of battery discharge and flight mission assessment for electrical rotorcraft |date=2018}}</ref> 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.<ref>{{cite journal |last1=González-Jorge |first1=H. |title=manned aerial systems for civil applications: A review |journal=Drones |date=2017|volume=1 |page=2 |doi=10.3390/drones1010002 |doi-access=free }}</ref><ref name=Fredericks20nov2018/>{{Clarify|reason=why more power needed for landing?|date=November 2021}} 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]]-sized single-aisle would need 2 kWh/kg.<ref name=MRO10jan2019/>
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.<ref>{{Cite web|url=https://www.kijkmagazine.nl/tech/elektrisch-vliegen/|title=3 alternatieve oplossingen voor schonere luchtvaart|date=5 March 2019|language=NL}}</ref>{{better source needed|reason=an english ref would be better|date=November 2021}}
 
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 ${{Format price|{{#expr:30/300}}}} Canadian per kWh compared to $2.00 per liter for gas,<ref name=sustainableskies12dec2019/> providing {{cvt|{{#expr:44*.75}}|MJ|kWh}} of energy with a 44 MJ/kg fuel and a 0.75 density [[Avgas]], ${{#expr:2/9.2round2}} per chemical kWh or ${{#expr:2/9.2*3round2}} per shaft kWh with an efficiency of one third.<!-- 300kWH/kg batteries don't exist, and the 1 ton battery used was certainly way less than that, maybe one half, and the reported 20 U. S gallons (79.4L) of avgas cannot be compared directly--> [[Jet fuel]] is cheaper and large gas turbine are more efficient, though. In 2021, beyond-lithium-ion technologies such as [[Solid-state battery]] ([[Lithium–sulfur battery|lithium-sulfur]], LSB) and [[Lithium–air battery|lithium-air batteries]] (LAB) have become increasingly promising areas of research for more competitive battery-electric aircraft performance.<ref>{{cite journal |last1=Dornbusch |first1=D. |title=Practical considerations in designing solid state Li-S cells for electric aviation |journal=Electrochimica Acta |date=2021|volume=403 |page=139406 |doi=10.1016/j.electacta.2021.139406 |s2cid=244619978 |doi-access=free }}</ref><ref>{{cite journal |last1=Duffner |first1=F. |title=Post-lithium-ion battery cell production and its compatibility with lithium-ion cell production infrastructure |journal=Nature Energy |date=2021|volume=6 |issue=2 |page=123 |doi=10.1038/s41560-020-00748-8 |bibcode=2021NatEn...6..123D |s2cid=234033882 }}</ref>
 
<!--Charging-->
The [[SAE International]] AE-7D<ref>{{Cite web|url=https://www.sae.org/works/committeeHome.do?comtID=TEAAE7D|title=SAE Standards Works}}</ref> 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]]s for [[electric car]]s which can also charge aircraft.<ref name="General">{{cite web|last=Johnsen|first=Frederick|date=11 August 2019|title=Electric aircraft await juice jockeys|url=https://generalaviationnews.com/2019/08/11/electric-aircraft-await-juice-jockeys/|access-date=17 April 2021|work=General Aviation News}}</ref>
 
===Ultracapacitors===
An [[ultracapacitor]] 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.<ref>{{cite journal |last1=Häggström |first1=Fredrik |last2=Delsing |first2=Jerker |title=IoT Energy Storage – A Forecast |journal=Energy Harvesting and Systems |date=27 November 2018 |volume=5 |issue=3–4 |pages=43–51 |doi=10.1515/ehs-2018-0010 |s2cid=64526195 |url=https://www.researchgate.net/publication/328810651 |access-date=30 October 2020|doi-access=free }}</ref>{{Better source needed|date=November 2021|reason=needs aircraft}}
 
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.<ref name=Brown>{{cite web|last=Brown|first=Nicholas|title=Cheaper Ultracapacitors For Electric Vehicles|url=https://cleantechnica.com/2011/05/11/cheaper-ultracapacitors-for-electric-vehicles/#:~:text=Supercapacitors%20last%20significantly%20longer%20than,may%20be%20cheaper%20or%20comparable.|work=cleantechnica.com|access-date=17 April 2021|date=11 May 2011}}</ref>{{Better source needed|date=November 2021|reason=old}}
 
===Fuel cells===
[[File:Pipistrel Taurus G4 take-off at 2011 Green Flight Challenge.jpg|thumb|The Taurus G4 taking off from the [[Sonoma County Airport]] in California]]
 
{{See also|Hydrogen-powered aircraft}}
A [[fuel cell]] (FC) uses the reaction between two chemicals such as [[hydrogen]] and [[oxygen]] to create electricity, much like a [[liquid-propellant rocket]] 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===
[[File:AERO Friedrichshafen 2018, Friedrichshafen (1X7A4751).jpg|thumb|The [[Siemens SP200D]] motor powering the [[Airbus CityAirbus]]]]
 
Almost all electric aircraft to date have been powered by [[electric motor]]s driving thrust-generating [[propeller]]s or lift-generating [[rotorcraft|rotor]]s.<ref>{{cite journal|url=http://mdolab.engin.umich.edu/content/electric-hybrid-and-turboelectric-fixed-wing-aircraft-review-concepts-models-and-design|title= Electric, Hybrid, and Turboelectric Fixed-Wing Aircraft: A Review of Concepts, Models, and Design Approaches|journal= Progress in Aerospace Sciences |volume= 104|pages= 1–19|date=January 2019|doi= 10.1016/j.paerosci.2018.06.004|last1= Brelje|first1= Benjamin J.|last2= Martins|first2= Joaquim R.R.A.|bibcode= 2019PrAeS.104....1B|doi-access= }}</ref>
 
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.<ref name=sustainableskies12dec2019>{{cite web|last=Sigler|first=Dean|title=Electric Beaver Flies in Vancouver, B. C.|url=http://sustainableskies.org/electric-beaver-flies-vancouver-b-c/|website=sustainableskies.org|date=12 December 2019}}</ref><ref>{{cite web|title=Ultra lightweight motors for electric drones and airliners|url=https://www.idtechex.com/fr/research-article/ultra-lightweight-motors-for-electric-drones-and-airliners/7674|website=www.idtechex.com|date=10 April 2015}}</ref> Electric motors also do not lose power with altitude, unlike internal-combustion engines,<ref name="General" /> avoiding the need for complex and costly measures used to prevent this, such as the use of [[turbocharger]]s.
 
The experimental [[Extra 330]]LE have a {{cvt|260|kW|hp}} [[Siemens SP260D]] motor weighing 50&nbsp;kg, with a {{#expr:18.6*2}} kWh battery pack, for an aircraft weight of 1,000&nbsp;kg.<ref>{{cite press release |url= https://cleantechnica.com/2018/01/28/extra-aircraft-330le-two-seat-electric-airplane-another-electric-airplane-moving-clean-air-race-forward/ |title= The "Extra Aircraft 330LE" Two-Seat Electric Airplane — Another Electric Airplane Moving The Clean Air Race Forward |author= Nicolas Zart |date= January 28, 2018 |work= cleantechnica}}</ref> It replaces a 235&nbsp;kW (315&nbsp;hp) [[Lycoming AEIO-580]] piston engine weighing 202&nbsp;kg.<ref>{{cite news |url= https://www.easa.europa.eu/sites/default/files/dfu/IO-580%20series%20TCDS%20issue%2003.pdf |title= TYPE-CERTIFICATE DATA SHEET No. IM.E.027 |date= 7 May 2020 |publisher= European Union Aviation Safety Agency}}</ref> The piston-engine Extra 330 empty weight is 677&nbsp;kg,<ref>{{cite web |title=EXTRA 330LT |url=https://www.extraaircraft.com/330LT.php |publisher=Extra Flugzeugproduktions - und Vertriebs - GmbH }}</ref> {{#expr:677-203}} kg without the engine. The Lycoming engine has a fuel consumption of {{cvt|141|lb|0}} per hour when outputting {{cvt|315|hp|kW|0}},<ref>{{cite web |url= https://www.lycoming.com/sites/default/files/IO-580-B1A%20Oper%20%26%20Install%20Manual%2060297-28.pdf |title= I0-580-B1A Operation and Installation Manual |publisher= Lycoming |date= April 2003}}</ref> or {{#expr:64/235round2}} kg/kWh: it needs {{#expr:37.2*0.27round1}} 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&nbsp;nmi alternate plus 30 minutes of holding before landing – 308&nbsp;kg of fuel for a turboprop, or 4,300&nbsp;kg of 250 Wh/kg batteries, similar to a current 19-seater empty weight.<ref>{{cite news |url= https://leehamnews.com/2021/07/01/the-true-cost-of-electric-aircraft/ |title= The true cost of Electric Aircraft |author= Bjorn Fehrm |date= July 1, 2021 |work= Leeham News}}</ref> An electric propulsion system also includes a [[power inverter]], while fuel engines have a [[Aircraft fuel system|fuel system]] themselves.
 
The {{cvt|750|shp}} experimental [[magniX]] magni500 electric motor weighs {{cvt|297|lb}},<ref>{{cite web |author= Jake Richardson |title= 750 Horsepower Electric Aviation Engine Tested By MagniX |url= https://cleantechnica.com/2019/10/24/750-horsepower-electric-aviation-engine-tested-by-magnix/ |date= 24 October 2019 |work= cleantechnica}}</ref> while the {{cvt|729|hp}} certified [[Pratt & Whitney Canada PT6]]A-114 weighs {{cvt|297|lb}},<ref name="PTTC">{{cite web |url= http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/90c641493420043b8625752f006482e8/$FILE/E4EA_rev24.pdf |title= Pratt & Whitney Canada PT6 Series Type Certificate |date= 2007-06-21 |publisher= [[Federal Aviation Administration]] }}</ref> both powering the [[Cessna 208 Caravan]].
 
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.<ref name=General/> 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.<ref name=General/>
 
=== Hybrid power ===
{{Main|Hybrid electric aircraft}}
 
A [[hybrid electric aircraft]] is an [[aircraft]] with a [[Hybrid electric vehicle|hybrid electric]] 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.<ref name=IEEE1jun2018/>
By May 2018, there were over 30 projects, and [[short-haul]] hybrid-electric airliners were envisioned from 2032.<ref name=AvWeek24aug2018>{{cite news |url= http://aviationweek.com/future-aerospace/aerospace-sector-could-see-overhaul-electric-propulsion |title= Aerospace Sector Could See Overhaul From Electric Propulsion |date= Aug 24, 2018 |author=Michael Bruno |work= Aviation Week & Space Technology}}</ref> The most advanced are the [[Zunum Aero]] 10-seater,<ref name=Flight5oct2017>{{cite news |url= https://www.flightglobal.com/news/articles/zunum-launches-hybrid-electric-aircraft-for-regional-441877/ |title= Zunum launches hybrid-electric aircraft for regional market |date= Oct 5, 2017 |author= Stephen Trimble |work= Flightglobal}}</ref> the [[Airbus E-Fan X]] demonstrator,<ref name=28nov2017PR>{{cite press release|url= https://www.siemens.com/press//pool/de/pressemitteilungen/2017/corporate/PR2017110098COEN.pdf |title= Airbus, Rolls-Royce, and Siemens team up for electric future |date= 28 Nov 2017 |publisher= Airbus, Rolls-Royce, Siemens }} ([http://www.airbus.com/newsroom/press-releases/en/2017/11/airbus--rolls-royce--and-siemens-team-up-for-electric-future-par.html Airbus], [https://www.rolls-royce.com/media/press-releases/yr-2017/28-11-2017-airbus-rr-and-siemens-team-up-for-electric-future.aspx Rolls-Royce], [https://www.siemens.com/press/PR2017110098COEN Siemens])</ref> the [[VoltAero Cassio]],<ref name=AvWeek25oct2018>{{cite news |url= http://aviationweek.com/future-aerospace/e-fan-experience-spawns-french-hybrid-electric-startup |title= E-Fan Experience Spawns French Hybrid-Electric Startup |date= Oct 25, 2018 |author= Graham Warwick |work= Aviation Week & Space Technology}}</ref> [[United Technologies Corp.|UTC]] is modifying a [[Bombardier Dash 8]],<ref name=AvWeek26mar2019>{{cite news |url= https://aviationweek.com/future-aerospace/utc-s-dash-8-hybrid-electric-x-plane-targets-commercial-market |title= UTC's Dash 8 Hybrid-Electric X-Plane Targets Commercial Market |date= Mar 26, 2019 |author= Graham Warwick |work= Aviation Week & Space Technology}}</ref> while the [[Ampaire Electric EEL]] prototype first flew on 6 June 2019.<ref name=Ampaire6jun2019>{{cite press release |url= https://www.ampaire.com/news/public-reveal-060619 |title= Ampaire Announces First Public Electric Flight |date= June 6, 2019 |publisher= Ampaire}}</ref>
 
===Magnetohydrodynamics===
{{Main|Ion-propelled aircraft}}
In November 2018, [[MIT]] engineers achieved the first free flight with a model aircraft having no moving parts, the [[MIT EAD Airframe Version 2|EAD Airframe Version 2]]. It is propelled by creating an [[ion wind]] using [[magnetohydrodynamics]] (MHD).<ref>{{cite news |url= https://news.mit.edu/2018/first-ionic-wind-plane-no-moving-parts-1121 |title= MIT engineers fly first-ever plane with no moving parts |author= Jennifer Chu |work= MIT News|date= November 21, 2018}}</ref><ref>{{cite journal |last1=Xu |first1=Haofeng |last2=He |first2=Yiou |last3=Strobel |first3=Kieran L. |last4=Gilmore |first4=Christopher K. |last5=Kelley |first5=Sean P. |last6=Hennick |first6=Cooper C. |last7=Sebastian |first7=Thomas |last8=Woolston |first8=Mark R. |last9=Perreault |first9=David J. |last10=Barrett |first10=Steven R. H. |date=2018-11-21 |title=Flight of an aeroplane with solid-state propulsion |journal=Nature |volume=563 |issue=7732 |pages=532–535 |doi=10.1038/s41586-018-0707-9 |pmid=30464270 |bibcode=2018Natur.563..532X |s2cid=53714800 }}</ref> 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==
Line 129 ⟶ 40:
===Unmanned aircraft===
 
In 1909, an electric [[Free flight (model aircraft)|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.<ref>{{cite book |author= Dave Day |title= Electric Flight |chapter= History of Electric Flight |publisher= Argus Books |year= 1983 |chapter-url= http://www.windyurtnowski.com/DaveDay/hist.htm |access-date= 2017-07-12 |archive-date= 2018-08-24 |archive-url= https://web.archive.org/web/20180824230325/http://www.windyurtnowski.com/DaveDay/hist.htm |url-status= dead }}</ref> Power density for electric flight was problematic even for small models.
 
[[File:Pathfinder Plus solar aircraft over Hawaii.jpg|thumb|The [[NASA Pathfinder Plus]] electric-powered [[unmanned aerial vehicle]]]]
 
[[NASA Pathfinder|NASA's Pathfinder, Pathfinder Plus]], [[NASA Centurion|Centurion]], and [[NASA Helios|Helios]] were a series of solar and fuel cell system–powered unmanned aerial vehicles (UAVs) developed by [[AeroVironment]], Inc. from 1983 until 2003 under [[NASA]]'s [[Environmental Research Aircraft and Sensor Technology]] program.<ref name=heliosfact>{{cite web|url=http://www.nasa.gov/centers/dryden/news/FactSheets/FS-068-DFRC.html|title=NASA Armstrong Fact Sheet: Helios Prototype|work=NASA|access-date=8 December 2015|date=2015-08-13|archive-date=2010-11-24|archive-url=https://web.archive.org/web/20101124125752/http://www.nasa.gov/centers/dryden/news/FactSheets/FS-068-DFRC.html|url-status=dead}}</ref><ref name=goebel12>{{Cite web|url=http://www.vectorsite.net/twuav_12.html|archive-url=https://web.archive.org/web/20130730032004/http://www.vectorsite.net/twuav_12.html|url-status=dead|title=None|archive-date=July 30, 2013}}</ref> On September 11, 1995, Pathfinder set an unofficial altitude record for solar-powered aircraft of {{convert|50000|ft}} during a 12-hour flight from [[Dryden Flight Research Center|NASA Dryden]]. After further modifications, the aircraft was moved to the [[U.S. Navy]]'s [[Pacific Missile Range Facility]] (PMRF) on the Hawaiian island of [[Kauai]]. On July 7, 1997, Pathfinder raised the altitude record for solar–powered aircraft to {{convert|71530|ft}}, which was also the record for propeller–driven aircraft.<ref name=heliosfact/>
 
On August 6, 1998, Pathfinder Plus raised the national altitude record to {{convert|80201|ft|m}} for solar-powered and propeller-driven aircraft.<ref name=heliosfact/><ref>{{cite web|url=http://www.naa.aero/html/records/search_resultsguest.cfm?recordNumber=1855|title=NAA Record Detail|work=naa.aero|access-date=8 December 2015|url-status=usurped|archive-url=https://web.archive.org/web/20120212230625/http://www.naa.aero/html/records/search_resultsguest.cfm?recordNumber=1855|archive-date=12 February 2012}}</ref>
Line 139 ⟶ 50:
On August 14, 2001, Helios set an altitude record of {{convert|96863|ft|order=flip}} – the record for FAI class U (experimental/new technologies), and FAI class U-1.d (remotely controlled UAV with a mass between {{cvt|500|and|2500|kg}}) as well as the altitude record for propeller–driven aircraft.<ref>{{cite web|title=Aviation and Space World Records|url=http://www.fai.org/fai-record-file/?recordId=7354|publisher=Fédération Aéronautique Internationale|access-date=14 October 2013|archive-url=https://web.archive.org/web/20131016223325/http://www.fai.org/fai-record-file/?recordId=7354|archive-date=16 October 2013|url-status=dead}}</ref> 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, [[AC Propulsion]] flew 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.<ref>{{Cite web|url=https://solarimpulse.com/|archive-url=https://web.archive.org/web/20110628112136/http://solarimpulse.com/common/documents/challenge_history.php?lang=en&group=challenge|url-status=dead|title=Solar Impulse Foundation: 1000 profitable solutions for the environment|first=Solar|last=Impulse|archive-date=28 June 2011|website=solarimpulse.com|access-date=20 August 2019}}</ref><ref>[http://www.renewableenergyworld.com/rea/news/article/2005/07/solar-plane-breaks-two-night-flight-barrier-34057 Solar Plane Breaks Two-Night Flight Barrier] {{Webarchive|url=https://web.archive.org/web/20141218180509/http://www.renewableenergyworld.com/rea/news/article/2005/07/solar-plane-breaks-two-night-flight-barrier-34057 |date=2014-12-18 }} Renewable Energy World, July 5, 2005</ref>
 
The [[QinetiQ Zephyr]] is a lightweight solar-powered unmanned aerial vehicle (UAV). As of 23 July 2010 it holds the endurance record for an unmanned aerial vehicle of over 2 weeks (336 hours).<ref name="BBC20100723">{{cite news | last = Amos | first = Jonathan | title ='Eternal plane' returns to Earth | work = BBC News | date = 2010-07-23 | quote=touched down at 1504 BST ... on Friday ... took off ... at 1440 BST (0640 local time) on Friday, 9 July | url =https://www.bbc.co.uk/news/science-environment-10733998 | access-date = 2010-07-23}}</ref> It is of [[carbon fiber-reinforced polymer]] construction, the 2010 version weighing {{cvt|50|kg}}<ref name="BBC20100717">{{cite news | last = Amos | first = Jonathan | title = Zephyr solar plane flies 7 days non-stop | work = BBC News | date = 2010-07-17 | url = https://www.bbc.co.uk/news/science-environment-10664362 | access-date = 2010-07-17}}</ref> (the 2008 version weighed {{cvt|30|kg}}) with a [[wingspan|span]] of {{cvt|22.5|m}}<ref name="BBC20100717"/> (the 2008 version had a {{cvt|18|m}} wingspan). During the day it uses sunlight to charge [[Lithium–sulfur battery|lithium-sulphur batteries]], which power the aircraft at night.<ref name="QinetiQ">{{cite web|url = http://www.qinetiq.com/home/products/zephyr.html|title = Zephyr – QinetiQ High-Altitude Long-Endurance (HALE) Unmanned Aerial Vehicle (UAV)|access-date = 2008-09-14|last = QinetiQ Group PLC|year = n.d.|archive-url = https://web.archive.org/web/20080826234154/http://www.qinetiq.com/home/products/zephyr.html|archive-date = 2008-08-26|url-status = dead}}</ref> 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 {{convert|70742|ft|m}} for FAI class U-1.c (remotely controlled UAV with a weight between {{cvt|50|and|500|kg}}).<ref name="BBC200808">{{cite news | last = Amos | first = Jonathan | title = Solar plane makes record flight | work = BBC News | date = 2008-08-24 | url = http://news.bbc.co.uk/2/hi/science/nature/7577493.stm | access-date = 2008-08-25}}</ref><ref name="AvWeb29Dec10">{{Cite news|url = http://www.avweb.com/avwebflash/news/SolarDroneSetsEnduranceRecord_203873-1.html |title = Solar Drone Sets Endurance Record|access-date = 30 December 2010|last = Grady|first = Mary|date=December 2010| work = AvWeb}}</ref><ref>{{cite web|title=Aviation and Space World Records|url=http://www.fai.org/fai-record-file/?recordId=16054|publisher=Fédération Aéronautique Internationale|access-date=14 October 2013|archive-date=16 April 2015|archive-url=https://web.archive.org/web/20150416054154/http://www.fai.org/fai-record-file/?recordId=16054|url-status=dead}}</ref>
 
{{See also|Unmanned aerial vehicle}}
Line 162 ⟶ 73:
In June 2017, Airbus presented its [[Airbus CityAirbus|CityAirbus]], an electrically powered [[vertical take-off and landing|VTOL]] aircraft demonstrator.<ref name=June2017Backgrounder/> The [[multirotor]] aircraft is intended to carry four passengers, with a pilot initially and to become self-piloted when regulations allow.<ref name=June2017Backgrounder>{{cite news |url= http://www.airbus.com/content/dam/corporate-topics/publications/backgrounders/City%20Airbus__Backgrounder_June2017.pdf |title= CityAirbus Backgrounder |date= June 2017 |publisher= Airbus}}</ref> Its first unmanned flight was scheduled for the end of 2018 with manned flights planned to follow in 2019.<ref name=Flight20dec2017>{{cite news |url= https://www.flightglobal.com/news/articles/airbus-helicopters-powers-up-cityairbus-iron-bird-444351/ |title= Airbus Helicopters powers up CityAirbus 'iron bird' rig |date= 20 Dec 2017 |author= Dominic Perry |work= Flightglobal}}</ref> [[Type certificate|Type certification]] and commercial introduction are planned for 2023.<ref name=Airbus3Oct2017>{{cite press release |url= http://www.airbus.com/newsroom/press-releases/en/2017/10/cityairbus-demonstrator-passes-major-propulsion-testing-mileston.html |title= CityAirbus demonstrator passes major propulsion testing milestone |date= 3 October 2017 |publisher= Airbus}}</ref>
 
[[Ingenuity (helicopter)|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]]s. The [[Dragonfly (spacecraftTitan space probe)|Dragonfly]] 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.<ref>Lorenz, R. D. Planetary Exploration with Ingenuity and Dragonfly: Rotary-Wing Flight on Mars and Titan. Library of Flight, AIAA, 2022. {{ISBN|978-1-62410-636-1}}</ref>
 
===Experimental demonstrators===
Line 172 ⟶ 83:
Following successful [[human-powered flight]], a relaunched [[Kremer prize]] allowed the crew to store energy before takeoff.<ref>{{Cite web|url=https://www.flightglobal.com/FlightPDFArchive/1985/1985%20-%200745.PDF|title=''Flight'', 16 March 1985|access-date=20 August 2019}}</ref> In the 1980s several such designs stored electricity generated by pedalling, including the [[MIT Monarch]] and the [[Aerovironment]] Bionic Bat.<ref>[http://arc.aiaa.org/doi/abs/10.2514/6.1985-1447 Bionic Bat – Stored energy human powered aircraft] M. Cowley, AeroVironment, Inc., Simi Valley, CA; W. MORGAN, AeroVironment, Inc., Simi Valley, CA; P. MACCREADY, AeroVironment, Inc., Monrovia, CA Chapter DOI: 10.2514/6.1985-1447 Publication Date: 8 July 1985 – 11 July 1985</ref>
 
The [[Boeing]]-led FCD (fuel cell demonstrator) project uses a [[Diamond HK-36 Super Dimona]] motor glider as a research test bed for a hydrogen fuel cell powered light airplane.<ref name="AvWeb04Apr08">{{cite web|url = http://www.avweb.com/avwebflash/news/BoeingFliesFuelCellAircraft_197531-1.html|title = Boeing Flies Fuel Cell Aircraft |access-date = 2008-05-13|last = Niles|first = Russ|date=April 2008}}</ref> Successful flights took place in February and March 2008.<ref name="AvWeb04Apr08"/><ref name="Apr08Times">{{cite news|url=http://business.timesonline.co.uk/tol/business/industry_sectors/transport/article3675188.ece|archive-url=https://web.archive.org/web/20110612042658/http://business.timesonline.co.uk/tol/business/industry_sectors/transport/article3675188.ece|url-status=dead|archive-date=June 12, 2011|title=Boeing tests first hydrogen powered plane|work=The Times|author=David Robertson|date=2008-04-03 | location=London}}</ref>
 
The European Commission has financed many low [[Technology readiness level|TRL]] projects for innovative electric or hybrid propulsion aircraft. The ENFICA-FC is a project of the [[European Commission]], 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 [[Kappa 77 KP 2U-SOVA|Rapid 200FC]] ultralight aircraft on 20 May 2010.<ref name="ENFICA">{{cite web|url=http://www.enfica-fc.polito.it|title=ENFICA-FC – ENvironmentally Friendly Inter City Aircraft powered by Fuel Cells|author=Politecnico di Torino|work=polito.it|access-date=8 December 2015}}</ref>
Line 187 ⟶ 98:
 
===Solar aircraft===
{{See also|Solar-powered aircraft}}
[[File:Mauro Solar Riser.jpg|thumb|The [[Mauro Solar Riser]], the first solar-powered aircraft, flew on April 29, 1979]]
[[File:Solar Impulse SI2 pilote Bertrand Piccard Payerne November 2014.jpg|thumb|In 2016, [[Solar Impulse]] 2 was the first solar-powered aircraft to complete a [[circumnavigation]]]]
Line 212 ⟶ 123:
The first commercially available, non-certified production electric aircraft, the [[Alisport Silent Club]] self-launching [[Glider (sailplane)|glider]], flew in 1997. It is optionally driven by a {{cvt|13|kW}} DC electric motor running on {{cvt|40|kg}} of batteries that store {{cvt|1.4|kWh}} of energy.<ref name="SilentElectric">{{cite web|url = http://www.alisport.com/eu/eng/silent_b.htm|title = Silent Club: Electric Self-launch Sailplane|access-date = 2009-11-04|last = AliSport|year = n.d.|url-status = dead|archive-url = https://web.archive.org/web/20090420110802/http://www.alisport.com/eu/eng/silent_b.htm|archive-date = 2009-04-20}}</ref>
 
The first certificate of airworthiness for an electric powered aircraft was granted to the [[Lange Antares]] 20E in 2003. Also an electric, self-launching {{cvt|20|m}} glider/sailplane, with a {{cvt|42|kW}} DC/DC brushless motor and [[lithium-ion battery|lithium-ion batteries]], it can climb up to {{cvt|3000|m}} with fully charged cells.<ref>[http://www.lange-flugzeugbau.com/htm/english/news/news.html 06.09.2011: SWR.de The Research Aircraft Antares DLR H2 and Antares H3] {{webarchive|url=https://web.archive.org/web/20060812184635/http://www.lange-flugzeugbau.com/htm/english/news/news.html |date=2006-08-12 }}</ref> The first flight was in 2003. In 2011 the aircraft won the 2011 Berblinger competition.<ref name="2011 Berblinger competition">{{Cite web|url=http://www.berblinger.ulm.de/en|title=Berblinger Wettbewerb 2013 Ulm|website=www.berblinger.ulm.de|access-date=20 August 2019|archive-date=11 April 2015|archive-url=https://web.archive.org/web/20150411174638/http://www.berblinger.ulm.de/en|url-status=dead}}</ref>
 
In late 2000s Chinese manufacturer of radio-controlled models [[Yuneec International]] developed and tested several battery-powered manned fixed-wing aircraft, including [[Yuneec International E430|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 [[Pipistrel Taurus|Taurus Electro]] was the first two-seat electric aircraft to have ever flown,<ref name="electro_announce">{{cite web |title=First {{sic|Annou|cement:|nolink=y}} Taurus ELECTRO |url=http://www.pipistrel.si/eng/news/725 |website=Pipistrel Aircraft |archive-url=https://web.archive.org/web/20081215053035/http://www.pipistrel.si/eng/news/725 |archive-date=15 December 2008 |date=21 December 2007}}</ref> while the Taurus Electro G2 is the production version, that was introduced in 2011. Powered by a {{convert|40|kW|hp|0|abbr=on}} electric motor and lithium batteries for self-launching<ref name="AvWeb15Feb11">{{Cite news|url = https://www.avweb.com/news/pipistrel-launches-electric-motorglider/ |title = Pipistrel Launches Electric Motorglider|access-date = 17 February 2011|last = Grady|first = Mary|date=February 2011| work = AvWeb}}</ref> to an altitude of {{cvt|2000|m|ft}}, 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.<ref name="electroG2_first">{{cite web |title=Taurus Electro – Overview |url=http://www.pipistrel.si/plane/taurus-electro/overview |website=Pipistrel Aircraft |archive-url=https://web.archive.org/web/20110902225034/http://www.pipistrel.si/plane/taurus-electro/overview |archive-date=2 September 2011}}</ref><ref name="Arts_Electro-first">{{cite web |title=A journey through the history of electric aircraft – It is almost half a century since the first manned, electrically propelled flight |url=https://arts.eu/journey-through-the-history-of-electric-aircraft |website=Arts.eu |date=7 January 2020 |access-date=29 April 2020}}</ref>
 
As pilot training emphasises short flights, several companies make, or have demonstrated, light aircraft suitable for initial flight training. The [[Airbus E-Fan]] was aimed at flight training but the project was cancelled. [[Pipistrel]] makes light sport electric aircraft such as the [[Pipistrel WATTsUP]], 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.
Line 226 ⟶ 137:
On 12 October 2021, [[Diamond Aircraft Industries|Diamond Aircraft]] announced the development of the e[[DA40]], targeting a 2022 first flight and a 2023 EASA/FAA Part 23 certification, tailored to the flight training market.<ref name=Diamond12oct2021>{{cite press release |url= https://www.diamondaircraft.com/en/about-diamond/newsroom/news/article/diamond-aircraft-announces-future-all-electric-trainer-and-partnership-with-electric-power-systems/ |date= 12 October 2021 |title= Diamond Aircraft announces future All-Electric Trainer and partnership with Electric Power Systems |publisher= Diamond Aircraft}}</ref> The two-seat aircraft is expected to be able to fly for up to 90 minutes, with 40% lower operating costs than piston power. The eDA40 has a planned three-seat variant for future release.<ref name=futureflight2021-10-13>{{Cite web|last=Alcock|first=Charles|date=October 13, 2021|title=Diamond Unveils Plans for All-Electric eDA40 Training Aircraft|url=https://www.futureflight.aero/news-article/2021-10-13/diamond-unveils-plans-all-electric-eda40-training-aircraft|website=FutureFlight}}</ref>
The eDA40 had its initial flight on 20 July 2023.<ref>{{Cite web |date=2023-07-26 |title=Maiden Flight of the Diamond Aircraft eDA40 |url=https://www.diamondaircraft.com/en/about-diamond/newsroom/news/article/maiden-flight-of-the-diamond-aircraft-eda40/ |access-date=2023-09-29 |website=www.diamondaircraft.com |language=en-ca}}</ref>
 
[[File:Integral E.jpg|thumb|Integral E]]
 
On 19 February 2024, [[Aura Aero]] rolls-out its first prototype of Integral E.
 
===Airliner projects===
Line 231 ⟶ 146:
[[File:NASA Electric Aircraft Testbed.jpg|thumb|[[NASA Electric Aircraft Testbed]]]]
 
The [[NASA Electric Aircraft Testbed]] (NEAT) is a NASA reconfigurable [[testbed]] in [[Plum Brook Station]], Ohio, used to design, develop, assemble and test electric aircraft power systems, from a small, one or two person aircraft up to {{cvt|20|MW}} [[airliner]]s.<ref>{{cite news |url= https://www.nasa.gov/feature/it-s-electric-nasa-glenn-engineers-test-next-revolution-aircraft |date= Oct 17, 2016 |title= It's Electric! NASA Glenn Engineers Test Next Revolution Aircraft |author= Deborah Lockhart |publisher= NASA Glenn Research Center}}</ref> NASA research agreements (NRA) are granted to develop electric-propulsion components.<ref name="AvWeek25Aug2017/"> They will be completed in 2019{{updatecite news after|2019}}author=Graham andWarwick the|date=Aug internal25, NASA work by 2020,{{update2017 after|2020}}title=NASA thenMoves they will be assembled in a megawattElectric-scalePropulsion driveComponents systemCloser toTo be tested in the [[narrowbody]]-sized NEAT.<ref name=AvWeek25Aug2017>{{cite newsReality |url= http://aviationweek.com/commercial-aviation/nasa-moves-electric-propulsion-components-closer-reality |title= NASA Moves Electric-Propulsion Components Closer To Reality |date= Aug 25, 2017 |author= Graham Warwick |work= Aviation Week & Space Technology}}</ref> That programme was cancelled in 2023.
 
In September 2017, UK budget carrier [[EasyJet]] announced it was developing an electric 180-seater for 2027 with [[Wright Electric]].<ref>{{cite news |url= http://atwonline.com/airframes/easyjet-joins-electric-aircraft-project |title= EasyJet joins electric aircraft project |date= Sep 27, 2017 |author= Victoria Moores |work= Aviation Week Network }}</ref> Founded in 2016, US [[Wright Electric]] built a two-seat proof-of-concept with 272&nbsp;kg (600&nbsp;lb) of batteries, and believes they can be scaled up with substantially lighter new [[Electric battery#Comparison|battery chemistries]]. A 291&nbsp;nmi (540&nbsp;km) range would suffice for 20% of Easyjet passengers.<ref>{{cite news |url= https://www.flightglobal.com/news/articles/easyjet-unveils-short-haul-electric-aircraft-ambitio-441543/ |title= EasyJet unveils short-haul electric aircraft ambition |date= 27 September 2017 |author= Dominic Perry |work= Flightglobal }}</ref> 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.<ref>{{cite web|author=Monaghan, Angela |date=27 September 2017|url=https://www.theguardian.com/business/2017/sep/27/easyjet-electric-planes-wright-electric-flights| title=EasyJet says it could be flying electric planes within a decade |work=[[The Guardian]]|access-date=28 September 2017}}</ref> Jeffrey Engler, CEO of Wright Electric, estimates that commercially viable electric planes will lead to around a 30% reduction in energy costs.<ref>{{cite news |url= https://www.reuters.com/article/us-easyjet-ceo-electric-idUSKCN1N31PS |title= EasyJet expects to be flying electric planes by 2030 |date= 29 October 2018 |author= Sarah Young |work= Reuters }}</ref>
Line 238 ⟶ 153:
 
Australia-based [[MagniX]] has developed an electric [[Cessna 208 Caravan]] with a {{cvt|540|kW}} motor for flight durations up to an hour.<ref name=AvWeek7jun2018/>
The company's Magni5 electric motor produces continuously {{cvt|265|kW}}, {{cvt|300|kW}} peak at 2,500 rpm at 95% efficiency with a 53&nbsp;kg (117&nbsp;lb) dry mass, a 5&nbsp;kW/kg power density, competing with the {{cvt|260|kW}}, {{cvt|50|kg}} [[Siemens SP260D]] for the [[Extra EA-300|Extra 330LE]].<ref name=AvWeek7jun2018>{{cite news |url= http://aviationweek.com/aviation-week-space-technology/magnix-promises-electrically-powered-cessna-caravan-summer-2019 |title= MagniX Promises Electrically Powered Cessna Caravan By Summer 2019 |date= Jun 7, 2018 |author= Michael Bruno |work= Aviation Week & Space Technology}}</ref> By September 2018, a {{cvt|350|hp}} electric motor with a propeller had been tested on a Cessna iron bird. The {{cvt|750|hp}} Caravan was expectedfirst toflew flyin by the fall of 2019{{update after|2019}}2020 and by 2022 MagniX estimates electric aircraft will have ranges of {{cvt|500|and|1000|miles}} by 2024.{{update after|2024}}<ref>{{cite news |url= https://www.ainonline.com/aviation-news/business-aviation/2018-09-27/magnix-reaches-milestone-path-electric-propulsion |title= MagniX Reaches Milestone on Path to Electric Propulsion |author= Alexa Rexroth |date= September 27, 2018 |work= AIN online}}</ref> The motor ran on a test [[dynamometer]] for 1,000 hours.<ref name=AvWeek28sep2018/> The iron bird is a Caravan forward fuselage used as a test bed, with the original [[Pratt & Whitney Canada PT6]] turboprop engine replaced by an electric motor, inverter and a liquid-cooling system, including radiators, driving a [[Cessna 206]] propeller.<ref name=AvWeek28sep2018/> The production motor will produce {{cvt|280|kW}} at 1,900 rpm, down from the test motor's 2,500 rpm, allowing the installation without a reduction gearbox.<ref name=AvWeek28sep2018>{{cite news |url= http://aviationweek.com/future-aerospace/magnix-advances-electric-propulsion-system-tests |title= MagniX Advances Electric Propulsion System Tests |date= Sep 28, 2018 |author= Graham Warwick |work= Aviation Week & Space Technology }}</ref> On 28 May 2020, the MagniX electric-powered nine-passenger [[Cessna 208B]] ''eCaravan'' flew on electric power,<ref>{{cite web|url=https://www.bbc.com/future/article/20200617-the-largest-electric-plane-ever-to-fly|title=The largest electric plane ever to fly|date=18 June 2020|website=BBC}}</ref> towards commercial operation certification.<ref>{{cite web|last=Mark|first=Rob|title=An Electrically Powered Cessna Caravan Continues Progress|url=https://www.flyingmag.com/story/aircraft/cessna-caravan-electric-power-progress/|work=flying magazine|date=22 December 2020}}</ref>
 
A 560-kW (750-hp) MagniX electric motor was installed in a [[de Havilland Canada DHC-2 Beaver]] seaplane. [[Harbour Air]], based in [[British Columbia]], 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.<ref name=AvWeek10oct2019/> On December 10, 2019, it made its first flight of four minutes duration from the [[Fraser River]] near [[Vancouver]]. The normally-fitted [[Pratt & Whitney R-985 Wasp Junior]] piston engine of the six-passenger Beaver was replaced by a 135&nbsp;kg (297&nbsp;lb) [[MagniX#Products|magni500]], with swappable batteries, allowing 30 minute flights with a 30-minute reserve.<ref>{{cite news |author= Jon Hemmerdinger |title= Harbour Air flies 'first' all-electric commercial aircraft, a DHC-2 Beaver |url= https://www.flightglobal.com/news/harbour-air-flies-first-all-electric-commercial-aircraft-a-dhc-2-beaver/135711.article |work= FlightGlobal|date=10 December 2019}}</ref> By April 2022, flight testing of a certifiable version through a [[supplemental type certificate|STC]] was delayed until late 2023, to carry four passengers and a pilot on 30 minute flights with a 30-minute reserve.<ref name=Flight27apr2022/> Magnix is seeking [[Federal Aviation Administration|FAA]] certification for its 640&nbsp;kW (850shp) Magni650 aircraft engine, while battery provider [[H55]] (a spin-off from Solar Impulse) is pursuing [[EASA]] approval.<ref name=Flight27apr2022>{{cite news |url= https://www.flightglobal.com/airlines/harbour-air-plans-first-flight-of-certifiable-electric-beaver-by-end-2023/148412.article |title= Harbour Air plans first flight of certifiable electric Beaver by end-2023 |author= Dominic Perry |date= 27 April 2022 |work= Flightglobal}}</ref>
Line 249 ⟶ 164:
 
On 22 March 2021, [[Toulouse]]-based Aura Aero announced the development of its ERA (Electric Regional Aircraft), a 19-passenger electric aircraft, planned to be certified in 2026.{{update after|2026}}<ref>{{cite news | url= https://www.thetimes.co.uk/article/aura-aero-electric-planes-np2362l2f | title= French electric airliner will take to the skies in five years | author= Charles Bremner | date= 27 March 2021 }}</ref>
 
==Environmental effects of aviation==
{{main|Environmental effects of aviation}}
The [[environmental effects of aviation]] on [[climate change]] 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 {{CO2}} emissions, and its emissions of air transportation altogether increased by 32% between 2013 and 2018.<ref name=AirInt>{{cite web|last=Broadbent|first=Mark|title=Do airlines dream of electric fleets?|url=https://www.airinternational.com/article/do-airlines-dream-electric-fleets|work=www.airinternational.com|publisher=Key Publishing|location=Lincs, UK|date=13 February 2020|access-date=17 April 2021}}</ref> While estimating aviation's non-{{CO2}} effects on climate change is complex, [[NOx]] and [[contrail]]s could increase this responsibility to 3.5%.<ref>{{Cite web|title=Aviation is responsible for 3.5 percent of climate change, study finds|url=https://research.noaa.gov/article/ArtMID/587/ArticleID/2667/Aviation-is-responsible-for-35-percent-of-climate-change-study-finds|date=2020-09-03|work=NOAA Research}}</ref> Other benefits are the potential for noise reduction, in an industry with a severe [[Aircraft noise pollution|noise pollution]] and [[noise abatement|abatement]] problem.<ref name=sustainableskies12dec2019/>
 
==Offboard power supply==
Mechanisms for supplying the necessary electricity without storing all of it onboard include:
*[[Solar cell]]s convert sunlight directly into electricity using [[photovoltaic]] materials.
*[[Microwave]] energy that is [[Power beaming|beamed]] from a remote transmitter.
*[[Power cable]]s connected to a ground-based electrical supply.
 
===Solar cells===
[[File:Pathfinder being prepared for flight - GPN-2000-000238.jpg|thumb|[[Solar panel]]s on the [[NASA Pathfinder]] wing's upper surface]]
 
A [[solar cell]] 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 {{cvt|150|-|200|W/m2}} in direct sunlight.<ref name=Catlow>{{cite web|last=Catlow|first=Amy |title=How Much Electricity Can I Generate with Solar Panels?|url=https://www.theecoexperts.co.uk/solar-panels/how-much-electricity|website=www.theecoexperts.co.uk|access-date=18 April 2021|date=26 May 2020}}</ref> 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.<ref name=Murphy215>{{cite book|last=Murphy|first=Thomas W. Jr.|title=Energy and Human Ambitions on a Finite Planet|url=https://escholarship.org/uc/item/9js5291m|publisher=eScholarship|date=11 March 2021|isbn=978-0578867175|page=215}}</ref>
 
Between 2010 and 2020, solar power modules have declined in cost by 90% and continue to drop by 13–15% per year.<ref name=IRENA>{{cite book|last1=Taylor|first1=Michael|last2=Ralon|first2=Pablo|last3=Anuta|first3=Harold|last4=Al-Zoghoul |first4=Sonia|title=Renewable Power Generation Costs in 2019|publisher=[[International Renewable Energy Agency]] (IRENA)|location=Abu Dhabi|isbn=978-9292602444|year=2020|page=21|url=https://www.irena.org/publications/2020/Jun/Renewable-Power-Costs-in-2019|access-date=18 April 2021}}</ref> [[Solar cell efficiency]] 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.<ref name=PV>{{cite web|last=Han|first=Amos|title=Efficiency Of Solar PV, Then, Now And Future|url=https://sites.lafayette.edu/egrs352-sp14-pv/technology/history-of-pv-technology/|access-date=18 April 2021|work=lafayette.edu}}</ref>
 
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.<ref name=cold>{{cite web|last=Murmson|first=Serm|title=Does a Solar Panel Stop Working When It Gets Too Cold?|url=https://sciencing.com/solar-panel-stop-working-gets-cold-8161.html|access-date=18 April 2021|work=sciencing.com|date=April 24, 2017}}</ref><ref name=Altitude>{{cite web|last=Luntz|first=Stephen|title=How Solar At High Altitudes Could Power Entire Countries, Even In Winter|url=https://www.iflscience.com/technology/how-solar-at-high-altitudes-could-power-entire-countries-even-in-winter/all/|access-date=18 April 2021|date=8 January 2019|archive-date=18 April 2021|archive-url=https://web.archive.org/web/20210418063649/https://www.iflscience.com/technology/how-solar-at-high-altitudes-could-power-entire-countries-even-in-winter/all/|url-status=dead}}</ref> The drop in the dry-air temperature as altitude increases, called the [[Lapse rate|environmental lapse rate (ELR)]], averages 6.49&nbsp;°C/km<ref name="ICAO 1993">{{cite book|publisher=[[International Civil Aviation Organization]]|title=Manual of the ICAO Standard Atmosphere (extended to 80 km (262,500 ft))|id=Doc 7488-CD|edition=Third|year=1993|isbn=9789291940042}}</ref> (memorized in pilot training as 1.98&nbsp;°C/1,000&nbsp;ft or 3.56&nbsp;°F/1,000&nbsp;feet) so that temperature for a typical airliner's cruising altitude of around {{cvt|35000|ft}} 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]] of electromagnetic energy such as [[microwave]]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.<ref name="Power Beaming">{{Cite web|url=http://www.dfrc.nasa.gov/gallery/Photo/Power-Beaming/index.html|archive-url=https://web.archive.org/web/20130217082723/http://www.dfrc.nasa.gov/gallery/Photo/Power-Beaming/index.html|url-status=dead|title=Power Beaming|archive-date=17 February 2013|access-date=20 August 2019}}</ref>
 
===External power cables===
For powered vehicles replacing tethered [[aerostat]]s, an electrical [[power cable]] can be connected to a ground-based supply, such as an electric generator or the local [[power grid]]. At low altitudes this avoids having to lift batteries, and was used by the experimental [[Petróczy-Kármán-Žurovec|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:
*[[electric battery|Batteries]] which use a chemical reaction to generate electricity which is reversed when recharged.
*[[Fuel cell]]s consume fuel and an oxidizer in a chemical reaction to generate electricity, they need to be refueled, typically with hydrogen.
 
===Batteries===
[[File:Tier1 Engineering - Electric Helicopter Batteries.jpg|thumb|[[Electric batteries|Batteries]] for the Tier1 Engineering electric [[Robinson R44]]]]
 
Batteries are the most common onboard [[energy carrier|energy storage]] 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]]. Modern batteries are mostly rechargeable types based on lithium technologies.
 
[[Lithium polymer batteries]] (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.<ref>{{cite book |last1=Boggio-Dandry |first1=Andrew |title=2018 9th IEEE Annual Ubiquitous Computing, Electronics & Mobile Communication Conference (UEMCON) |chapter=Perpetual Flight for UAV Drone Swarms Using Continuous Energy Replenishment |publisher=IEEE |date=2018 |volume=2018 9th IEEE Annual Ubiquitous Computing, Electronics & Mobile Communication Conference (UEMCON) |pages=478–484 |doi=10.1109/UEMCON.2018.8796684 |isbn=978-1-5386-7693-6 |s2cid=201069705 |chapter-url=https://ieeexplore.ieee.org/document/8796684}}</ref> 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 [[Energy_density|battery specific energy]].<ref>{{cite journal |last1=González-Jorge |first1=H. |title=nmanned aerial systems for civil applications: A review |journal=Drones |date=2017|volume=1 |page=2 |doi=10.3390/drones1010002 |doi-access=free }}</ref><ref name=Fredericks20nov2018>{{cite journal |last1=Fredericks |first1=W. |title=Performance Metrics Required of Next-Generation Batteries to Electrify Vertical Takeoff and Landing (VTOL) Aircraft |journal=ACS Energy Letters |date= November 20, 2018 |volume=3 |issue=12 |pages=2989–2994 |doi=10.1021/acsenergylett.8b02195 |s2cid=115445306 |doi-access=free }}</ref> 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&nbsp;kg) and average energy density (150 Wh/kg) could travel a range of ~80&nbsp;mi with one passenger, ~60&nbsp;mi with two, and less than ~30&nbsp;mi with three.<ref name=Fredericks20nov2018/>
 
In 2017 the power available from batteries was estimated at 170 Wh/kg, 145 Wh/kg at the shaft including the system efficiency, while a [[gas turbine]] extracted 6,545 Wh/kg of shaft power from an 11,900 Wh/kg fuel.<ref>{{cite news |url= https://leehamnews.com/2017/06/30/bjorns-corner-electric-aircraft/ |title= Bjorn's Corner: Electric aircraft |author= Bjorn Fehrm |date= June 30, 2017 |work= Leeham}}</ref> In 2018 [[lithium-ion batteries]] including packaging and accessories were estimated to give 160 Wh/kg while aviation fuel gave 12,500 Wh/kg.<ref name=IEEE1jun2018>{{cite news |url= https://spectrum.ieee.org/hybrid-electric-airliners-will-cut-emissionsand-noise |date= 1 Jun 2018 |title= Hybrid Electric Airliners Will Cut Emissions—and Noise |author= Philip E. Ross |work= [[IEEE Spectrum]]}}</ref> In 2018 the [[specific energy]] of [[electricity storage]] was still only 2% of [[aviation fuel]].<ref>{{cite news |url= https://www.flightglobal.com/news/articles/ebace-cessna-short-circuits-talk-of-electric-powere-448953/ |title= Cessna short-circuits talk of electric-powered aircraft |date= 28 May 2018 |author= Stephen Trimble |work= Flightglobal}}</ref> This 1:50 ratio makes electric propulsion impractical for long-range aircraft, as a {{cvt|500|nmi|km}} mission for an all-electric, 12-passenger aircraft would require a six-fold increase in battery power density.<ref name=MRO10jan2019>{{cite news |last=Seidenman|first=Paul|url=https://www.mro-network.com/engines-engine-systems/how-batteries-need-develop-match-jet-fuel|archive-url=https://web.archive.org/web/20190419070640/https://www.mro-network.com/engines-engine-systems/how-batteries-need-develop-match-jet-fuel|url-status=dead|archive-date=April 19, 2019|title=How Batteries Need To Develop To Match Jet Fuel|date=Jan 10, 2019|work=Aviation Week Network}}</ref> That said, battery-electric motors have a higher efficiency (~90%) than most jet engines (~50%), which can be further exploited through emerging battery chemistries.<ref name=Schäfer10dec2018>{{cite journal |last1=Schäfer |first1=A. |title=Technological, economic and environmental prospects of all-electric aircraft |journal=Nature Energy |year=2019 |volume=4 |issue=2 |pages=160–166 |doi=10.1038/s41560-018-0294-x |hdl=1721.1/126682 |s2cid=134741946 |url= https://www.nature.com/articles/s41560-018-0294-x |url-access= subscription|hdl-access=free }}</ref>
 
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.<ref>{{cite web|last1=Lineberger|first1=R.|title=Change is in the air: The elevated future of mobility: What's next on the horizon?|url=https://www2.deloitte.com/us/en/insights/focus/future-of-mobility/evtol-elevated-future-of-mobility-summary.html|url-status=live|date= 3 June 2019|website=Deloitte|archive-url=https://web.archive.org/web/20191026093211/https://www2.deloitte.com/us/en/insights/focus/future-of-mobility/evtol-elevated-future-of-mobility-summary.html |archive-date=2019-10-26 }}</ref><ref name="Alnaqeb2018">{{cite journal |last1=Alnaqeb |first1=Abdullah H. |last2=Li |first2=Yifei |last3=Lui |first3=Yu-Hui |last4=Pradeep |first4=Priyank |last5=Wallin |first5=Joshua |last6=Hu |first6=Chao |last7=Hu |first7=Shan |last8=Wei |first8=Peng |title=Online Prediction of Battery Discharge and Flight Mission Assessment for Electrical Rotorcraft|journal=2018 AIAA Aerospace Sciences Meeting |date=8 January 2018 |doi=10.2514/6.2018-2005|isbn=978-1-62410-524-1 |url=https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=7076&context=etd }}</ref> 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.<ref>{{cite journal |last1=González-Jorge |first1=H. |title=manned aerial systems for civil applications: A review |journal=Drones |date=2017|volume=1 |page=2 |doi=10.3390/drones1010002 |doi-access=free }}</ref><ref name=Fredericks20nov2018/>{{Clarify|reason=why more power needed for landing?|date=November 2021}} 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]]-sized single-aisle would need 2 kWh/kg.<ref name=MRO10jan2019/>
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.<ref>{{Cite web|url=https://www.kijkmagazine.nl/tech/elektrisch-vliegen/|title=3 alternatieve oplossingen voor schonere luchtvaart|date=5 March 2019|language=NL}}</ref>{{better source needed|reason=an english ref would be better|date=November 2021}}
 
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 ${{Format price|{{#expr:30/300}}}} Canadian per kWh compared to $2.00 per liter for gas,<ref name=sustainableskies12dec2019/> providing {{cvt|{{#expr:44*.75}}|MJ|kWh}} of energy with a 44 MJ/kg fuel and a 0.75 density [[Avgas]], ${{#expr:2/9.2round2}} per chemical kWh or ${{#expr:2/9.2*3round2}} per shaft kWh with an efficiency of one third.<!-- 300kWH/kg batteries don't exist, and the 1 ton battery used was certainly way less than that, maybe one half, and the reported 20 U. S gallons (79.4L) of avgas cannot be compared directly--> [[Jet fuel]] is cheaper and large gas turbine are more efficient, though. In 2021, beyond-lithium-ion technologies such as [[Solid-state battery]] ([[Lithium–sulfur battery|lithium-sulfur]], LSB) and [[Lithium–air battery|lithium-air batteries]] (LAB) have become increasingly promising areas of research for more competitive battery-electric aircraft performance.<ref>{{cite journal |last1=Dornbusch |first1=D. |title=Practical considerations in designing solid state Li-S cells for electric aviation |journal=Electrochimica Acta |date=2021|volume=403 |page=139406 |doi=10.1016/j.electacta.2021.139406 |s2cid=244619978 |doi-access=free }}</ref><ref>{{cite journal |last1=Duffner |first1=F. |title=Post-lithium-ion battery cell production and its compatibility with lithium-ion cell production infrastructure |journal=Nature Energy |date=2021|volume=6 |issue=2 |page=123 |doi=10.1038/s41560-020-00748-8 |bibcode=2021NatEn...6..123D |s2cid=234033882 }}</ref>
 
<!--Charging-->
The [[SAE International]] AE-7D<ref>{{Cite web|url=https://www.sae.org/works/committeeHome.do?comtID=TEAAE7D|title=SAE Standards Works}}</ref> 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]]s for [[electric car]]s which can also charge aircraft.<ref name="General">{{cite web|last=Johnsen|first=Frederick|date=11 August 2019|title=Electric aircraft await juice jockeys|url=https://generalaviationnews.com/2019/08/11/electric-aircraft-await-juice-jockeys/|access-date=17 April 2021|work=General Aviation News}}</ref>
 
===Ultracapacitors===
An [[ultracapacitor]] 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.<ref>{{cite journal |last1=Häggström |first1=Fredrik |last2=Delsing |first2=Jerker |title=IoT Energy Storage – A Forecast |journal=Energy Harvesting and Systems |date=27 November 2018 |volume=5 |issue=3–4 |pages=43–51 |doi=10.1515/ehs-2018-0010 |s2cid=64526195 |url=https://www.researchgate.net/publication/328810651 |access-date=30 October 2020|doi-access=free }}</ref>{{Better source needed|date=November 2021|reason=needs aircraft}}
 
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.<ref name=Brown>{{cite web|last=Brown|first=Nicholas|title=Cheaper Ultracapacitors For Electric Vehicles|url=https://cleantechnica.com/2011/05/11/cheaper-ultracapacitors-for-electric-vehicles/#:~:text=Supercapacitors%20last%20significantly%20longer%20than,may%20be%20cheaper%20or%20comparable.|work=cleantechnica.com|access-date=17 April 2021|date=11 May 2011}}</ref>{{Better source needed|date=November 2021|reason=old}}
 
===Fuel cells===
[[File:Pipistrel Taurus G4 take-off at 2011 Green Flight Challenge.jpg|thumb|The Taurus G4 taking off from the [[Sonoma County Airport]] in California]]
 
{{See also|Hydrogen-powered aircraft}}
A [[fuel cell]] (FC) uses the reaction between two chemicals such as [[hydrogen]] and [[oxygen]] to create electricity, much like a [[liquid-propellant rocket]] 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===
[[File:AERO Friedrichshafen 2018, Friedrichshafen (1X7A4751).jpg|thumb|The [[Siemens SP200D]] motor powering the [[Airbus CityAirbus]]]]
 
Almost all electric aircraft to date have been powered by [[electric motor]]s driving thrust-generating [[propeller]]s or lift-generating [[rotorcraft|rotor]]s.<ref>{{cite journal|url= http://mdolab.engin.umich.edu/content/electric-hybrid-and-turboelectric-fixed-wing-aircraft-review-concepts-models-and-design|title= Electric, Hybrid, and Turboelectric Fixed-Wing Aircraft: A Review of Concepts, Models, and Design Approaches|journal= Progress in Aerospace Sciences|volume= 104|pages= 1–19|date= January 2019|doi= 10.1016/j.paerosci.2018.06.004|last1= Brelje|first1= Benjamin J.|last2= Martins|first2= Joaquim R.R.A.|bibcode= 2019PrAeS.104....1B|doi-access= |s2cid= 115439116|access-date= 2019-03-17|archive-date= 2019-12-25|archive-url= https://web.archive.org/web/20191225173816/http://mdolab.engin.umich.edu/content/electric-hybrid-and-turboelectric-fixed-wing-aircraft-review-concepts-models-and-design|url-status= dead}}</ref>
 
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.<ref name=sustainableskies12dec2019>{{cite web|last=Sigler|first=Dean|title=Electric Beaver Flies in Vancouver, B. C.|url=http://sustainableskies.org/electric-beaver-flies-vancouver-b-c/|website=sustainableskies.org|date=12 December 2019}}</ref><ref>{{cite web|title=Ultra lightweight motors for electric drones and airliners|url=https://www.idtechex.com/fr/research-article/ultra-lightweight-motors-for-electric-drones-and-airliners/7674|website=www.idtechex.com|date=10 April 2015}}</ref> Electric motors also do not lose power with altitude, unlike internal-combustion engines,<ref name="General" /> avoiding the need for complex and costly measures used to prevent this, such as the use of [[turbocharger]]s.
 
The experimental [[Extra 330]]LE have a {{cvt|260|kW|hp}} [[Siemens SP260D]] motor weighing 50&nbsp;kg, with a {{#expr:18.6*2}} kWh battery pack, for an aircraft weight of 1,000&nbsp;kg.<ref>{{cite press release |url= https://cleantechnica.com/2018/01/28/extra-aircraft-330le-two-seat-electric-airplane-another-electric-airplane-moving-clean-air-race-forward/ |title= The "Extra Aircraft 330LE" Two-Seat Electric Airplane — Another Electric Airplane Moving The Clean Air Race Forward |author= Nicolas Zart |date= January 28, 2018 |work= cleantechnica}}</ref> It replaces a 235&nbsp;kW (315&nbsp;hp) [[Lycoming AEIO-580]] piston engine weighing 202&nbsp;kg.<ref>{{cite news |url= https://www.easa.europa.eu/sites/default/files/dfu/IO-580%20series%20TCDS%20issue%2003.pdf |title= TYPE-CERTIFICATE DATA SHEET No. IM.E.027 |date= 7 May 2020 |publisher= European Union Aviation Safety Agency}}</ref> The piston-engine Extra 330 empty weight is 677&nbsp;kg,<ref>{{cite web |title=EXTRA 330LT |url=https://www.extraaircraft.com/330LT.php |publisher=Extra Flugzeugproduktions – und Vertriebs – GmbH }}</ref> {{#expr:677-203}} kg without the engine. The Lycoming engine has a fuel consumption of {{cvt|141|lb|0}} per hour when outputting {{cvt|315|hp|kW|0}},<ref>{{cite web |url= https://www.lycoming.com/sites/default/files/IO-580-B1A%20Oper%20%26%20Install%20Manual%2060297-28.pdf |title= I0-580-B1A Operation and Installation Manual |publisher= Lycoming |date= April 2003 |access-date= 2021-11-22 |archive-date= 2021-11-22 |archive-url= https://web.archive.org/web/20211122160600/https://www.lycoming.com/sites/default/files/IO-580-B1A%20Oper%20%26%20Install%20Manual%2060297-28.pdf |url-status= dead }}</ref> or {{#expr:64/235round2}} kg/kWh: it needs {{#expr:37.2*0.27round1}} 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&nbsp;nmi alternate plus 30 minutes of holding before landing – 308&nbsp;kg of fuel for a turboprop, or 4,300&nbsp;kg of 250 Wh/kg batteries, similar to a current 19-seater empty weight.<ref>{{cite news |url= https://leehamnews.com/2021/07/01/the-true-cost-of-electric-aircraft/ |title= The true cost of Electric Aircraft |author= Bjorn Fehrm |date= July 1, 2021 |work= Leeham News}}</ref> An electric propulsion system also includes a [[power inverter]], while fuel engines have a [[Aircraft fuel system|fuel system]] themselves.
 
The {{cvt|750|shp}} experimental [[magniX]] magni500 electric motor weighs {{cvt|297|lb}},<ref>{{cite web |author= Jake Richardson |title= 750 Horsepower Electric Aviation Engine Tested By MagniX |url= https://cleantechnica.com/2019/10/24/750-horsepower-electric-aviation-engine-tested-by-magnix/ |date= 24 October 2019 |work= cleantechnica}}</ref> while the {{cvt|729|hp}} certified [[Pratt & Whitney Canada PT6]]A-114 weighs {{cvt|297|lb}},<ref name="PTTC">{{cite web |url= http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/90c641493420043b8625752f006482e8/$FILE/E4EA_rev24.pdf |title= Pratt & Whitney Canada PT6 Series Type Certificate |date= 2007-06-21 |publisher= [[Federal Aviation Administration]] |access-date= 2021-11-22 |archive-date= 2010-09-10 |archive-url= https://web.archive.org/web/20100910145359/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/90c641493420043b8625752f006482e8/$FILE/E4EA_rev24.pdf |url-status= dead }}</ref> both powering the [[Cessna 208 Caravan]].
 
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.<ref name=General/> 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.<ref name=General/>
 
=== Hybrid power ===
{{Main|Hybrid electric aircraft}}
 
A [[hybrid electric aircraft]] is an [[aircraft]] with a [[Hybrid electric vehicle|hybrid electric]] 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.<ref name=IEEE1jun2018/>
By May 2018, there were over 30 projects, and [[short-haul]] hybrid-electric airliners were envisioned from 2032.<ref name=AvWeek24aug2018>{{cite news |url= http://aviationweek.com/future-aerospace/aerospace-sector-could-see-overhaul-electric-propulsion |title= Aerospace Sector Could See Overhaul From Electric Propulsion |date= Aug 24, 2018 |author=Michael Bruno |work= Aviation Week & Space Technology}}</ref> The most advanced are the [[Zunum Aero]] 10-seater,<ref name=Flight5oct2017>{{cite news |url= https://www.flightglobal.com/news/articles/zunum-launches-hybrid-electric-aircraft-for-regional-441877/ |title= Zunum launches hybrid-electric aircraft for regional market |date= Oct 5, 2017 |author= Stephen Trimble |work= Flightglobal}}</ref> the [[Airbus E-Fan X]] demonstrator,<ref name=28nov2017PR>{{cite press release |url= https://www.siemens.com/press//pool/de/pressemitteilungen/2017/corporate/PR2017110098COEN.pdf |title= Airbus, Rolls-Royce, and Siemens team up for electric future |date= 28 Nov 2017 |publisher= Airbus, Rolls-Royce, Siemens }} ([http://www.airbus.com/newsroom/press-releases/en/2017/11/airbus--rolls-royce--and-siemens-team-up-for-electric-future-par.html Airbus], [https://www.rolls-royce.com/media/press-releases/yr-2017/28-11-2017-airbus-rr-and-siemens-team-up-for-electric-future.aspx Rolls-Royce] {{Webarchive|url=https://web.archive.org/web/20231106203218/https://www.rolls-royce.com/media/press-releases/2017/28-11-2017-airbus-rr-and-siemens-team-up-for-electric-future.aspx |date=2023-11-06 }}, [https://www.siemens.com/press/PR2017110098COEN Siemens])</ref> the [[VoltAero Cassio]],<ref name=AvWeek25oct2018>{{cite news |url= http://aviationweek.com/future-aerospace/e-fan-experience-spawns-french-hybrid-electric-startup |title= E-Fan Experience Spawns French Hybrid-Electric Startup |date= Oct 25, 2018 |author= Graham Warwick |work= Aviation Week & Space Technology}}</ref> [[United Technologies Corp.|UTC]] is modifying a [[Bombardier Dash 8]],<ref name=AvWeek26mar2019>{{cite news |url= https://aviationweek.com/future-aerospace/utc-s-dash-8-hybrid-electric-x-plane-targets-commercial-market |title= UTC's Dash 8 Hybrid-Electric X-Plane Targets Commercial Market |date= Mar 26, 2019 |author= Graham Warwick |work= Aviation Week & Space Technology}}</ref> while the [[Ampaire Electric EEL]] prototype first flew on 6 June 2019.<ref name=Ampaire6jun2019>{{cite press release |url= https://www.ampaire.com/news/public-reveal-060619 |title= Ampaire Announces First Public Electric Flight |date= June 6, 2019 |publisher= Ampaire |access-date= October 31, 2020 |archive-date= June 26, 2019 |archive-url= https://web.archive.org/web/20190626123702/https://www.ampaire.com/news/public-reveal-060619 |url-status= dead }}</ref>
 
===Magnetohydrodynamics===
{{Main|Ion-propelled aircraft}}
In November 2018, [[MIT]] engineers achieved the first free flight with a model aircraft having no moving parts, the [[MIT EAD Airframe Version 2|EAD Airframe Version 2]]. It is propelled by creating an [[ion wind]] using [[magnetohydrodynamics]] (MHD).<ref>{{cite news |url= https://news.mit.edu/2018/first-ionic-wind-plane-no-moving-parts-1121 |title= MIT engineers fly first-ever plane with no moving parts |author= Jennifer Chu |work= MIT News|date= November 21, 2018}}</ref><ref>{{cite journal |last1=Xu |first1=Haofeng |last2=He |first2=Yiou |last3=Strobel |first3=Kieran L.|last4=Gilmore |first4=Christopher K. |last5=Kelley |first5=Sean P.|last6=Hennick |first6=Cooper C.|last7=Sebastian |first7=Thomas |last8=Woolston |first8=Mark R. |last9=Perreault |first9=David J. |last10=Barrett |first10=Steven R. H. |date=2018-11-21|title=Flight of an aeroplane with solid-state propulsion |journal=Nature |volume=563 |issue=7732 |pages=532–535 |doi=10.1038/s41586-018-0707-9|pmid=30464270 |bibcode=2018Natur.563..532X |s2cid=53714800 }}</ref> 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.
 
== Shipments ==
Line 254 ⟶ 258:
 
{| class="wikitable"
|+Worldwide shipments of certified electric GA aircraft<ref name=QuarterlyReportGAMA>{{cite web|title=Quarterly Shipments and Billings – GAMA|url=https://gama.aero/facts-and-statistics/quarterly-shipments-and-billings/|website=gama.aero|access-date=2020-11-21|publication-date=}}.</ref>
!
!2020
!2021
!2022
!2023
|-
|[[Pipistrel Velis Electro]]
Line 264 ⟶ 269:
| align=right | {{#expr:14+8+6+20}}
|17
|16
|-
|'''Total'''
Line 269 ⟶ 275:
| align=right | '''{{#expr:14+8+6+20}}'''
|'''17'''
|'''16'''
|}
 
Retrieved from "https://en.wikipedia.org/wiki/Electric_aircraft"