Editing Turboprop (section)

==History==
[[File:Varga RMI-1 3-view (2).svg|thumb|Drawings of the Hungarian [[Varga RMI-1 X/H]] – the world's first working turboprop-powered aircraft.]]
[[Alan Arnold Griffith]] had published a paper on compressor design in 1926. [[Turbojet development at the RAE|Subsequent work at the Royal Aircraft Establishment]] investigated axial compressor-based designs that would drive a propeller. From 1929, [[Frank Whittle]] began work on centrifugal compressor-based designs that would use all the gas power produced by the engine for jet thrust.<ref>Gunston Jet, p. 120</ref>

The world's first turboprop was designed by the [[Hungary|Hungarian]] [[Mechanical engineering|mechanical engineer]] [[György Jendrassik]].<ref>Gunston World, p.111</ref> Jendrassik published a turboprop idea in 1928, and on 12 March 1929 he patented his invention. In 1938, he built a small-scale (100 Hp; 74.6&nbsp;kW) experimental gas turbine.<ref>{{cite web|url=http://www.sztnh.gov.hu/feltalalok/jendrass.html |title=Magyar feltalálók és találmányok – JENDRASSIK GYÖRGY (1898–1954) |publisher=SZTNH |access-date=2012-05-31}}</ref> The larger [[Jendrassik Cs-1]], with a predicted output of 1,000 bhp, was produced and tested at the [[Ganz Works]] in [[Budapest]] between 1937 and 1941. It was of axial-flow design with 15 compressor and 7 turbine stages, annular combustion chamber. First run in 1940, combustion problems limited its output to 400&nbsp;bhp. Two [[Jendrassik Cs-1]]s were the engines for the world's first turboprop aircraft – the [[Varga RMI-1 X/H]]. This was a [[Kingdom of Hungary (1920–1946)|Hungarian]] [[fighter-bomber]] of [[World War II|WWII]] which had one model completed, but before its first flight it was destroyed in a bombing raid.<ref>{{Cite web |title=The Jendrassik CS-1: The World's First Turboprop Engine |url=http://www.tailsthroughtime.com/2015/08/the-jendrassik-cs-1-worlds-first_25.html |access-date=4 September 2023 |website=www.tailsthroughtime.com}}</ref><ref>{{Cite web |title=RMI / Repülő Muszaki Intézet Varga RMI-1/ X / H |url=http://all-aero.com/index.php/125-planes-r-s/16508-rmi-varga-rmi-1-x-h |access-date=2023-09-04 |website=}}</ref> In 1941, the engine was abandoned due to war, and the factory converted to conventional engine production.

[[File:Rolls-Royce RB50 Trent Turboprop On Test Rig At Hucknall.jpg|thumb|A Rolls-Royce RB.50 ''Trent'' on a test rig at [[Hucknall]], in March 1945]]

The first mention of turboprop engines in the general public press was in the February 1944 issue of the British aviation publication ''[[Flight International|Flight]]'', which included a detailed cutaway drawing of what a possible future turboprop engine could look like. The drawing was very close to what the future Rolls-Royce Trent would look like.<ref>[https://www.flightglobal.com/pdfarchive/view/1951/1951%20-%200908.html "Our Contribution – How Flight Introduced and Made Familiar With Gas Turbines and Jet Propulsion"] ''Flight'', 11 May 1951, p. 569.</ref> The first British turboprop engine was the [[Rolls-Royce Limited|Rolls-Royce]] [[Rolls-Royce Trent (turboprop)|RB.50 Trent]], a converted [[Rolls-Royce Derwent|Derwent II]] fitted with reduction gear and a [[Rotol]] {{convert|7|ft|11|in|abbr=on}} five-bladed propeller. Two Trents were fitted to [[Gloster Meteor]] ''EE227'' — the sole "Trent-Meteor" — which thus became the world's first turboprop-powered aircraft to fly, albeit as a test-bed not intended for production.<ref>James p. 251-2</ref><ref>Green p.18-9</ref> It first flew on 20 September 1945. From their experience with the Trent, Rolls-Royce developed the [[Rolls-Royce Clyde]], the first turboprop engine to receive a [[type certificate]] for military and civil use,<ref>{{cite web|url=http://www.flightglobal.com/pdfarchive/view/1950/1950%20-%202035.html|title=rolls-royce trent – armstrong siddeley – 1950–2035 – Flight Archive|work=Flightglobal|access-date=31 August 2016}}</ref> and the [[Rolls-Royce Dart|Dart]], which became one of the most reliable turboprop engines ever built. Dart production continued for more than fifty years. The Dart-powered [[Vickers Viscount]] was the first turboprop aircraft of any kind to go into production and sold in large numbers.<ref>Green p.82</ref> It was also the first four-engined turboprop. Its first flight was on 16 July 1948. The world's first single engined turboprop aircraft was the [[Armstrong Siddeley Mamba]]-powered [[Boulton Paul Balliol]], which first flew on 24 March 1948.<ref>Green p.81</ref>

[[File:Kuznetsov NK-12M turboprop on Tu-95.jpg|thumb|The [[Kuznetsov NK-12]] is the most powerful turboprop to enter service]]

The Soviet Union built on German World War II turboprop preliminary design work by Junkers Motorenwerke, while BMW, [[Heinkel|Heinkel-Hirth]] and [[Daimler-Benz]] also worked on projected designs.<ref>Turbojet History And Development 1930-1960 Volume 1 Great Britain And Germany, Antony L. Kay 2007, {{ISBN|978 1 86126 912 6}}, various pages</ref> While the Soviet Union had the technology to create the airframe for a jet-powered strategic bomber comparable to Boeing's [[B-52 Stratofortress]], they instead produced the [[Tupolev Tu-95]] Bear, powered with four [[Kuznetsov NK-12]] turboprops, mated to eight [[contra-rotating propellers]] (two per nacelle) with supersonic tip speeds to achieve maximum cruise speeds in excess of 575&nbsp;mph, faster than many of the first [[jet aircraft]] and comparable to jet cruising speeds for most missions. The Bear would serve as their most successful long-range combat and surveillance aircraft and symbol of Soviet power projection through to the end of the 20th century. The USA used turboprop engines with contra-rotating propellers, such as the [[Allison T40]], on some experimental aircraft during the 1950s. The T40-powered [[Convair R3Y Tradewind]] flying-boat was operated by the U.S. Navy for a short time.

The first American turboprop engine was the [[GE Aviation|General Electric]] [[General Electric T31|XT31]], first used in the experimental [[Consolidated Vultee XP-81]].<ref>Green p.57</ref> The XP-81 first flew in December 1945, the first aircraft to use a combination of turboprop and [[turbojet]] power. The technology of Allison's earlier T38 design evolved into the [[Allison T56]], used to power the [[Lockheed L-188 Electra|Lockheed Electra]] airliner, its military maritime patrol derivative the [[P-3 Orion]], and the [[C-130 Hercules]] military transport aircraft.

The first turbine-powered, shaft-driven helicopter was the [[Kaman K-225]], a development of [[Charles Kaman]]'s K-125 [[synchropter]], which used a [[Boeing T50]] [[turboshaft]] engine to power it on 11 December 1951.<ref>{{cite web |url=http://airandspace.si.edu/collections/artifact.cfm?id=A19571016000 |title=Smithsonian National Air and Space Museum – Collections – Kaman K-225 ''(Long Description)'' |author=<!--Staff writer(s); no by-line.--> |publisher=National Air and Space Museum |access-date=4 April 2013 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304022530/http://airandspace.si.edu/collections/artifact.cfm?id=A19571016000 |url-status=dead }}</ref>

December 1963 saw the first delivery of [[Pratt & Whitney|Pratt & Whitney Canada's]] [[PT6]] turboprop engine for the then Beechcraft 87, soon to become [[Beechcraft King Air]].<ref>{{Cite web |title=PT6 60 YEARS - Pratt & Whitney |url=https://www.pwc.ca/en/landing-pages-folder/pt6-60-years |access-date=2023-06-27 |website=www.pwc.ca}}</ref>

1964 saw the first deliveries of the [[Garrett AiResearch]] [[Honeywell TPE331|TPE331]], (now owned by [[Honeywell Aerospace]]) on the [[Mitsubishi MU-2]], making it the fastest turboprop aircraft for that year.<ref>{{Cite web |title=Evolution of the Honeywell TPE331 |url=https://aerospace.honeywell.com/us/en/pages/evolution-of-the-honeywell-tpe331 |access-date=2023-06-27 |website=aerospace.honeywell.com |language=en-US}}</ref>