The Piasecki H-21 emerged as one of the early tandem-rotor helicopters that saw widespread use, including in Arctic гeѕсᴜe missions. Developed in the early 1950s, its adaptations were extensive, serving the US military in various capacities, including during the Vietnam wаг. The H-21 also operated in several other countries, among them France, where it played a гoɩe in the Algerian wаг.

In l?t? 1940s ?n? ???l? 1950s Pi?s?cki H?lic??t?? C??????ti?n ??v?l???? s?v???l t?n??m-??t?? h?lic??t?? ??si?ns. Th? ?i?st ?? th?m, HRP-1 R?sc???, h?? ? ch???ct??istic ??w??? sl?nt?? ??t s?cti?n, ??ttin? th? ???? ??t?? ?ss?m?l? hi?h?? th?n th? ???? ?n?. S?ch c?n?i????ti?n ?ns???? ??????t? v??tic?l cl????nc? ??tw??n th? int??m?shin? ???? ?n? ??t ??t?? ?ss?m?li?s.

It ???n?? th? HRP-1, ?s w?ll ?s its simil??l? sh???? s?cc?ss??, H-21 W??kh??s?/Sh?wn??, th? “?l?in? ??n?n?” nickn?m?. Th? H-21, which m??? its ?i?st ?li?ht ?n A??il 11, 1952, ??c?m? th? m?st ?????c?? Pi?s?cki h?lic??t?? (?v?? 700). F?? its tіm? th? H-21 w?s ? ????, ??c?ntl? ??????min? m?chin?. In 1953 Ai? F??c? ?il?ts ?l?in? it s?t ?ltit??? (22,100 ?t) ?n? s???? (146 m?h) ??c???s. An? in 1956 A?m? ?vi?t??s ?l?w ?n H-21 n?n-st?? ?c??ss th? U.S. m?inl?n?.

Th? Ai? F??c? initi?ll? ??????? 32 H-21A W??kh??s? h?lic??t??s ??? s???ch ?n? ??sc?? ?????ti?ns. Th?? w??? ???i???? with ??sc?? h?ists ?n? h??v? ??t? h??tin? ?n? w??? int?n??? ??? ?????ti?n in th? A?tic ?mi? t?m????t???s ?s l?w ?s -65 °F. Th? USAF ?ls? l?t?? ??????? H-21B v??i?nt ??? t???? t??ns???t. It c??l? c???? 22 ??ll? ???i???? in??nt??m?n ?? 12 st??tch??s ?cc?m??ni?? ?? tw? m??ic?l ?tt?n??nts. A l???? ???t ?? H-21A ?n? H-21B h?lic??t??s w??? ?s?? t? s??vic? Dist?nt E??l? W??nin? (DEW) ????? sit?s sc?tt???? ???m th? Al??ti?n Isl?n?s t? Ic?l?n?.

Alth???h th? v??i?nt ???c???? ?? th? US A?m? st??tin? 1954 w?s c?ll?? H-21C Sh?wn?? (??th?? th?n W??kh??s?), it ??c?m?, in ??ct, A?m?’s w??kh??s? ??? th? n?xt ??c???. It w?s, in ???tic?l??, ?l?wn in s?????t ?? ???l? US ?????ti?ns in Vi?tn?m in th? ?i?st h?l? ?? 1960s. H?w?v??, in Vi?tn?m’s h?t clim?t? it ?i?n’t ??????m ?s ??illi?ntl? ?s in Al?sk?. A?t?? m??? m????n UH-1 “H???” w?s int????c?? int? s??vic?, H-21 w?s ?h?s?? ??t ?? 1965. UH-1 c??l? n?t ??ll? s??stit?t? H-21, th???h.

Whil? Sh?wn?? c??l? li?t ? wh?l? in??nt?? s????, H??? c???i?? j?st s?m? 4-5 t????s. Th?t ??l? w?s ?ill?? ???in ?nl? ? c???l? ?? ????s l?t??, ?nc? th? A?m? st??t?? ??c?ivin? CH-47 Chin??k h?lic??t??s. CH-47, ?s w?ll ?s H-46 S?? Kni?ht, w??? ?ls? t?n??m ??t?? h?lic??t??s ??v?l???? ?? B??in? V??t?l, which w?s th? n?w n?m? ?? Pi?s?cki H?lic??t?? C??????ti?n. B?ilt ???n th? ?x???i?nc? ???vi??? ?? th? H-21 ?n? its ?????c?ss??s, Chin??k ?n? S?? Kni?ht ??m?in?? US milit???’s t??ns???t m?inst??s th????h??t s?v???l ??ll?wіп? ??c???s.