Douglas DC-8

**Douglas DC-8** (wani lokacin **McDonnell Douglas DC-8**) jirgin sama ne na farko mai tsayi wanda kamfanin Douglas Aircraft na Amurka ya tsara kuma ya samar. An fara aiki a cikin 1952 zuwa ga bukatun Sojojin Sama na Amurka (USAF) don tankar mai amfani da jet. Bayan ya rasa gasar tankin AmurkaF ga abokin hamayyarsa Boeing KC-135 Stratotanker a watan Mayu na shekara ta 1954, Douglas ya sanar a watan Yunin shekara ta 1955 da aka samo aikin jetliner da aka sayar wa masu aikin farar hula. A watan Oktoba na shekara ta 1955, Pan Am ta yi umarni na farko tare da Boeing 707 mai fafatawa, kuma wasu kamfanonin jiragen sama da yawa sun biyo baya. An fitar da DC-8 na farko a Filin jirgin saman Long Beach a ranar 9 ga Afrilu, 1958, kuma ya tashi a karo na farko a ranar 30 ga Mayu. Bayan takardar shaidar Hukumar Kula da Sufurin Jiragen Sama ta Tarayya (FAA) a watan Agustan 1959, DC-8 ya shiga aiki tare da Delta Air Lines a ranar 18 ga Satumba.

Da yake ba da izinin zama shida, an fara samar da jirgin sama mai injin hudu, mai fuka-fuki a cikin nau'o'i hudu na   . DC-8-10 ya sami wutar lantarki ta Pratt &amp;amp; Whitney JT3C turbojets, kuma yana da    MTOW; DC-8-20 yana da ƙarfin JT4A turbojets mai ƙarfi, don    M TOW. Misalai na  suna da ƙarin ƙarfin man fetur, kuma suna da MTOW har zuwa   ; JT4As ne ya ba da wutar lantarki don Series 30, kuma ta Rolls-Royce Conway turbofans don Series 40. Pratt &amp;amp; Whitney JT3D ya ba da wutar lantarki ga DC-8-50 da Super 60 (DC-8-61, -62, da -63) da kuma nau'ikan jigilar kaya, kuma ya kai MTOW na   . Ba a yi la'akari da bambancin DC-8 da farko ba, wanda ya jagoranci wasu kamfanonin jiragen sama don yin odar Boeing 707 mai fafatawa a maimakon haka.

An sanar da ingantaccen Series 60 a watan Afrilun 1965. DC-8-61 an shimfiɗa ta    don kujeru 180-220 a cikin aji mai gauraye da MTOW na   . Ya fara tashi a ranar 14 ga Maris, 1966, an tabbatar da shi a ranar 2 ga Satumba, 1966, kuma ya shiga aiki tare da United Airlines a watan Fabrairun 1967. DC-8-62 mai nisa ya biyo baya a watan Afrilu na shekara ta 1967, wanda aka shimfiɗa da 7  , zai iya zama har zuwa fasinjoji 189 a kan  nautical miles [nmi] (9,600 km; 6,000  tare da fuka-fuki mafi girma don MTOW har zuwa   . DC-8-63 yana da dogon fuselage da fuka-fuki mai girma, masu jigilar kaya na MTOW sun kai   t).

An samar da DC-8 har zuwa 1972 tare da jirgin sama 556 da aka gina; an maye gurbinsa da manyan Jiragen sama masu faɗi ciki har da Douglas 'DC-10 trijet. Damuwar hayaniya ta haifar da buƙatar bambancin da ya fi dacewa; daga 1975, Douglas da Janar Electric sun ba da Series 70 retrofit, wanda ke da wutar lantarki ta hanyar injin turbofan CFM56 mai ƙarfi da mai amfani. Ya fi fita daga sabis na fasinja a cikin shekarun 1980 da 1990, amma wasu DC-8s da aka sake amfani da su a matsayin masu jigilar kaya.

## Ci gaba
A ƙarshen Yaƙin Duniya na II, Douglas shine babban mai samar da jirgin sama na Arewacin Amurka a kasuwar Jirgin sama na kasuwanci. Douglas ya samar da jerin jiragen sama masu amfani da piston (DC-2, DC-3, DC-4, DC-5, DC-6, da DC-7) a cikin shekarun 1930, 1940, da 1950. Yayinda de Havilland ya tashi jirgin sama na farko a duniya, Comet, a watan Mayu na shekara ta 1949,  Douglas da farko ya guji bunkasa jirgin sama

De Havilland ta farko Comet ta shiga aikin jirgin sama a watan Mayu 1952 .  Da farko, ya zama kamar nasara ne, amma an kafa Comet a cikin 1954 bayan haɗari biyu masu haɗari waɗanda daga baya aka danganta su da gazawar gajiya da sauri na ɗakin matsin lamba. Masu kera jiragen sama daban-daban sun amfana daga binciken da abubuwan da aka samu daga binciken da aka yi game da asarar Comet; musamman, Douglas ya mai da hankali sosai ga daki-daki a cikin ƙirar ɗakin DC-8 mai matsin lamba.   A shekara ta 1952, Douglas ya ci gaba da nasararsa a matsayin mai kera jirgin sama na kasuwanci, bayan ya sami kusan umarni 300 don injin piston DC-6 da magajinsa, DC-7, wanda har yanzu bai tashi ba. Bala'in Comet, da kuma rashin sha'awar kamfanonin jiragen sama, sun tabbatar da shawarar kamfanin na kasancewa tare da jirgin sama mai motsawa, amma rashin aikinsa ya ba masu masana'antun hamayya damar jagorantar a maimakon haka.

Tun a farkon 1949, kamfanin Boeing mai hamayya ya fara aikin ƙira a kan jirgin sama mai tsabta. Rundunar soji ta Boeing tana da gogewa tare da manyan jiragen sama masu nisa, kamar su B-47 Stratojet da B-52 Stratofortress. Yayinda yake samarwa da tallafawa waɗannan bama-bamai ga Sojojin Sama na Amurka (USAF), Boeing ya haɓaka kyakkyawar dangantaka da Kwamandan Jirgin Sama na AmurkaF (SAC). Har ila yau, kamfanin ya samar da jirgin saman SAC mai amfani da man fetur, KC-97 Stratofreighters mai amfani da piston, amma waɗannan sun tabbatar da cewa suna da jinkiri da ƙananan tashi don sauƙin aiki tare da sabbin bama-bamai. B-52, musamman, dole ne ya sauka daga tsayinsa na tafiya sannan ya ragu kusan zuwa saurin tsayawa don man fetur daga KC-97.  Da yake gaskata cewa abin da ake buƙata don tankar jet-powered tabbas ne, Boeing ya fara aiki a kan sabon jirgin sama na jet don wannan rawar da za a iya daidaita shi cikin jirgin sama. A matsayin jirgin sama, zai sami irin wannan damar zama ga Comet, amma amfani da fuka-fuki ya ba da damar saurin tafiya mafi girma da kuma mafi kyawun kewayon. Da farko an gabatar da shi a 1950 a matsayin Model 473-60C, Boeing ya kasa samar da wani sha'awa daga kamfanonin jiragen sama, duk da haka ya kasance da tabbacin cewa aikin ya cancanci kuma ya ci gaba da ci gaba tare da samfurin, Boeing 367-80 ("Dash-80"). Bayan kashe dala miliyan 16 na kuɗin kansa don gina shi, Dash-80 ya fito a ranar 15 ga Mayu, 1954.