{{short description|Hydrogen-powered aircraft type HY4}} {{Infobox aircraft | name = HY4 | logo = | logo_size = | image = HY4 2016-09-29 ueber Flughafen Stuttgart.jpg | alt = | caption = | long_caption = | other_names = | aircraft_type = Technology demonstrator | aim = | outcome = | related = | national_origin = Germany | manufacturer = DLR and Pipistrel | design_group = | designer = | builder = | issuer = | status = In development | owners = | primary_user = | more_users = | service = | major_applications = | proposals = | prototypes = | number_built = 1 | construction_number = | civil_registration = | military_serial = | radio_code = | requirement = | aircraft_carried = | flights = | total_hours = | total_distance = | construction_date = | introduction = | retired = | first_flight = 2016<ref name="HY4_firstflight">{{cite web |title=Zero-emission air transport – first flight of four-seat passenger aircraft HY4 |url=http://hy4.org/zero-emission-air-transport-first-flight-of-four-seat-passenger-aircraft-hy4 |website=HY4 |accessdate=29 April 2020 |archive-date=31 March 2018 |archive-url=https://web.archive.org/web/20180331010031/http://hy4.org/zero-emission-air-transport-first-flight-of-four-seat-passenger-aircraft-hy4 |url-status=dead }}</ref> | initiated = | in_service = | last_flight = | expected = | developed_from = Pipistrel Taurus G4 | variants = | developed_into = | preservation = | fate = | predecessors = | successors = | concluded = }}
'''HY4''' is a four seat hydrogen fuel cell powered aircraft. It made its maiden flight on 29 September 2016 from Stuttgart Airport, powered by gaseous hydrogen. It was designed by DLR Institute of Engineering Thermodynamics of the German Aerospace Center,<ref>{{cite web|url=https://www.aerospace-technology.com/projects/hy4-aircraft/|title=HY4 Aircraft|publisher=}}</ref><ref>{{cite web|url=https://www.aviationpros.com/aircraft/business-general-aviation/press-release/12264576/aircraft-maintenance-technology-hy4-maiden-flight-of-the-hydrogen-powered-airplane|title=HY4: Maiden Flight of the Hydrogen Powered Airplane|website=www.AviationPros.com}}</ref><ref>{{cite web|url=https://www.cnn.com/travel/article/hy4-fuel-cell-plane/index.html|title=The plane that emits only water|first=Sophie |last=Morlin-Yron|date=19 October 2016|website=CNN Travel}}</ref> based on the Taurus G4, manufactured by Pipistrel.<ref>{{cite web|url=http://www.digitaljournal.com/tech-and-science/technology/the-hy4-a-plane-that-runs-on-fuel-cells-and-emits-only-water/article/478172|title=The HY4 — a plane that runs on fuel cells and emits only water|date=26 October 2016|website=www.digitaljournal.com}}</ref>
The HY4, operated by DLR spinoff H2Fly, completed the world's first piloted electric flights powered by liquid hydrogen in September 2023, with one flight lasting over three hours.<ref>{{Cite web |date=September 18, 2023 |title=H2FLY's HY4 Completes First-Ever Piloted Flight Of Liquid Hydrogen-Powered Electric Plane |url=https://uk.news.yahoo.com/h2flys-hy4-completes-first-ever-150000395.html |access-date=January 16, 2026 |website=Yahoo! News}}</ref><ref>{{cite web|url=https://www.h2fly.de/2023/09/07/h2fly-and-partners-complete-worlds-first-piloted-flight-of-liquid-hydrogen-powered-electric-aircraft/|title=H2FLY And Partners Complete World’s First Piloted Flight of Liquid Hydrogen Powered Electric Aircraft|date=7 September 2023|website=www.h2fly.de}}</ref>
==References== {{Reflist}}
==External links== *{{official|http://hy4.org/}} *[https://www.h2fly.de/ H2Fly]
{{Commonscat|HY4}}
Category:2010s German experimental aircraft Category:Hydrogen-powered aircraft Category:Zero-emissions vehicles Category:Fuel cell vehicles