Fighter Bell P-63 Kingcobra
Bell P-63A-9 (42-69644) a daya daga cikin jiragen gwajin. Sarkin maƙarƙashiya bai ja hankalin sojojin saman Amurka ba, amma an ƙirƙira shi da yawa a farkon wuri.
ga Tarayyar Soviet.
The Bell P-63 Kingcobra shi ne na biyu na American laminar mayakan bayan Mustang da kuma kawai American jirgin saman soja kujeru guda da ya yi shawagi a cikin tsari bayan harin Japan a kan Pearl Harbor, kuma ya shiga cikin taro a lokacin yakin. Kodayake R-63 bai tada sha'awar Sojan Sama ba, amma an samar da shi da yawa don bukatun abokan tarayya, musamman USSR. Bayan yakin duniya na biyu, an kuma yi amfani da Kingcobras wajen yaki da sojojin saman Faransa.
A ƙarshen 1940, masu aikin sa ido na Air Corps a Wright Field, Ohio, sun fara yarda cewa P-39 Airacobra ba zai yi babban mai ɗaukar hoto mai girma ba. Ingantaccen ci gaba a cikin halin da ake ciki zai iya kawo amfani da injin da ya fi ƙarfin da raguwar ja da iska. Zaɓin ya faɗi akan na'urar V-12-1430 1-cylinder in-line ruwa mai sanyaya V-injin tare da iyakar ƙarfin 1600-1700 hp. A shekarun baya, Rundunar Sojan Sama ta Amurka (USAAC) ta ba da jari mai tsoka wajen bunkasa ta, inda ta ke ganin ta a matsayin madadin injin Allison V-1710. A waccan shekarar, Kwamitin Ba da Shawarwari na Ƙasa na Aeronautics (NACA) ya yi abin da ake kira laminar airfoil bisa binciken da aka yi a Langley Memorial Aviation Laboratory (LMAL) ta UCLA wanda ya kammala karatun digiri na Eastman Nixon Jacobs. Sabuwar bayanin martabar an kwatanta shi da gaskiyar cewa matsakaicin kauri daga 40 zuwa 60 bisa dari. maƙiyi (bayanin martaba na al'ada suna da matsakaicin kauri wanda bai wuce kashi 25 cikin ɗari na ma'auni ba). Wannan ya ba da izinin kwararar laminar (rashin lafiya) a kan wani yanki mai girma da yawa, wanda hakan ya haifar da raguwar ja da iska. Masu zanen kaya da jami'an soji sun yi fatan cewa hadewar injin mai karfi tare da ingantacciyar tsarin iska zai kai ga samar da mai shiga tsakani mai nasara.
A tsakiyar Fabrairu 1941, masu zanen kamfanin Bell Aircraft sun sadu da wakilan sashen kayan aiki don tattauna yiwuwar gina sabon mayaƙa. Bell ya gabatar da shawarwari guda biyu, Model 23, P-39 da aka gyara tare da injin V-1430-1, da Model 24, sabon jirgin sama na reshe na laminar gaba ɗaya. Na farko yana da sauri don aiwatarwa muddin sabon injin yana samuwa akan lokaci. Na biyu yana buƙatar ƙarin lokaci mai yawa don lokacin bincike da haɓakawa, amma sakamakon ƙarshe yakamata ya kasance mafi kyau. Duk shawarwarin biyu sun ja hankalin USAAC kuma sun haifar da haɓaka XP-39E (wanda aka ambata a cikin labarin P-39 Airacobra) da P-63 Kingcobra. A ranar 1 ga Afrilu, Bell ya ƙaddamar da cikakken bayani game da Model 24 zuwa Sashen Kayayyakin, tare da kimanta farashi. Bayan kusan watanni biyu na tattaunawar, a ranar 27 ga Yuni, an ba Bell lambar kwangilar lambar W535-ac-18966 don gina samfura biyu masu tashi sama da 24, wanda aka keɓe XP-63 (lambobin serial 41-19511 da 41-19512; XR-631- 1) da gwaji a tsaye da gajiyawar jirgin sama na ƙasa.
Wannan aikin
Aiki a kan zane na farko na Model 24 ya fara ne a ƙarshen 1940. Ƙirar fasaha na XP-63 ta Eng. Daniel J. Fabrisi, Jr. Jirgin yana da irin wannan silhouette zuwa P-39, wanda ya kasance sakamakon kiyaye tsarin ƙira iri ɗaya - wani ɗan ƙaramin yanki na cantilever tare da na'ura mai saukowa mai sauƙi mai sauƙi tare da dabaran gaba, 37-mm. harbin bindiga ta hanyar burbushin burbushin injin, injin da ke kusa da tsakiyar ginin da kuma kokfit tsakanin bindigar da injin. Zane na jirgin saman ya kasance sabo. A lokacin tsarin zane, kusan dukkanin abubuwan da aka gyara da abubuwan tsarin sun ƙare, ta yadda a ƙarshe, R-39 da R-63 ba su da sassan gama gari. Idan aka kwatanta da R-39D, tsawon jirgin ya karu daga 9,19 zuwa 9,97 m, da span na kwance wutsiya daga 3962 zuwa 4039 mm, da waƙa na babban saukowa kaya daga 3454 zuwa 4343 mm, tushen saukowa kaya daga. 3042 mm. har zuwa 3282 mm. Sai kawai matsakaicin nisa na fuselage, ƙaddara ta nisa na injin, ya kasance ba canzawa kuma ya kai 883 mm. An gyaggyara alfarwar kokfit don haɗawa da ginanniyar gilas ɗin lebur mai kauri mai kauri mm 38 a cikin gilashin iska. Wutsiya a tsaye kuma tana da sabon siffa. An lulluɓe lif da rudders da zane, kuma an lulluɓe aileron da fafuna da ƙarfe. An kara girman fale-falen da ake cirewa da ƙyanƙyashe don sauƙaƙe wa injiniyoyi damar samun makamai da kayan aiki.
Koyaya, mafi mahimmancin ƙirƙira shine NACA 66 (215) -116/216 laminar fuka-fukan iska. Ba kamar fuka-fuki na P-39 ba, suna da zane wanda ya dogara da katako guda biyu - babba da na baya, wanda ya yi aiki don haɗa ailerons da flaps. Haɓakawa a cikin tushen tushen daga 2506 zuwa 2540 mm da tazara daga 10,36 zuwa 11,68 m ya haifar da haɓakar farfajiyar ƙasa daga 19,81 zuwa 23,04 m2. Fuka-fukan sun karkata zuwa ga fuselage a kusurwar 1°18' kuma suna da hawan 3°40'. Ana amfani da kofofin nadawa maimakon kofofin kada. An gwada nau'ikan sikelin 1:2,5 da 1:12 na fuka-fuki, wutsiya da duka jiragen sama a cikin tashoshin iska na NACA LMAL a filin Langley, Virginia da Wright Field. Gwaje-gwajen sun tabbatar da daidaiton ra'ayin Jacobs kuma a lokaci guda sun ba wa masu zanen Bell damar tsaftace zane na ailerons da flaps, da kuma siffar glycol da mai sanyaya iska.
Babban rashin lahani na fuka-fukan iska na laminar shine, don kiyaye kaddarorinsu na iska, dole ne su sami fili mai santsi, ba tare da fitowa fili da kusoshi da za su iya dagula motsin iska ba. Kwararrun NACA da masu zanen kaya sun damu game da ko tsarin samar da jama'a zai iya yin daidai da siffar bayanin martaba. Don gwada wannan, ma'aikatan Bell sun yi gwajin sabbin fuka-fuki, ba tare da sanin abin da suke yi ba. Bayan gwaji a cikin rami na iska na LMAL, ya nuna cewa fuka-fukan sun cika ka'idojin da aka kafa.
