|
The Flettner Fl 282 Kolibri ("Hummingbird") is a single-seat open cockpit intermeshing rotor helicopter, or ''synchropter'', produced by Anton Flettner of Germany. According to Yves Le Bec, the Flettner Fl 282 was the world's first series production helicopter.〔Le Bec, Yves. ''La véritable histoire de l'hélicoptère: De 1486 à 2005'' (French). Grossfeldstrasse, Switzerland: Hélico revue, 2005. ISBN 978-2-8399-0100-0.〕 ==Design and development== The Fl 282 ''Kolibri'' was an improved version of the Flettner Fl 265 announced in July 1940, which pioneered the same intermeshing rotor configuration that the ''Kolibri'' used. It had a 7.7 litre displacement, seven-cylinder Siemens-Halske Sh 14 radial engine of 150-160 hp mounted in the center of the fuselage, with a transmission mounted on the front of the engine from which a drive shaft ran to an upper gearbox, which then split the power to a pair of opposite-rotation drive shafts to turn the rotors. The Sh 14 engine was a tried-and-true design that only required servicing every 400 hours, as opposed to the nearly 27 litre displacement, nine-cylinder BMW/Bramo ''Fafnir'' radial engine powering the Focke Achgelis Fa 223, whose outdated design required maintenance every 25 hours. The Fl 282's fuselage was constructed from steel tube covered with doped fabric, and it was fitted with a fixed undercarriage. The German Navy was impressed with the ''Kolibri'' and wanted to evaluate it for submarine spotting duties, ordering an initial 15 examples, to be followed by 30 production models. Flight testing of the first two prototypes was carried out through 1941, including repeated takeoffs and landings from a pad mounted on the German cruiser ''Köln''. The first two "A" series prototypes had enclosed cockpits; all subsequent examples had open cockpits and were designated "B" series. In case of an engine failure, the switch from helicopter to autorotation was automatic.〔Smith and Kay 1978, p. 596.〕〔Lang, Gerhard. ''Flettner Fl 282 (The Luftwaffe Profile Series , No 6)''. Atglen, Pennsylvania: Schiffer Publishing, 1996. ISBN 0-88740-921-0.〕 Three-bladed rotors were installed on a test bed and found smoother than the vibrating 2-blade rotor, but the concept was not pursued further.〔 The hover efficiency ("Figure of Merit") was 0.72〔Jackson, Dave. "(Figure of Merit )" ''Unicopter'', 16 December 2011. Retrieved: 22 May 2015. (Archived ) on 26 November 2013.〕 whereas for modern helicopters it is around 60%.〔Whittle, Richard. "(It’s A Bird! It’s A Plane! No, It’s Aircraft That Fly Like A Bird! )" ''Breaking Defense'', 12 January 2015. Retrieved: 17 January 2015. (Archived ) on 1 May 2015.〕 After the war, Anton Flettner emigrated to the United States and became the chief designer for Kaman Aircraft, creating the Kaman HH-43 Huskie. Intermeshing rotors have become noted with Kaman helicopters, which continues this concept. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Flettner Fl 282」の詳細全文を読む スポンサード リンク
|