▁the ▁He inkel ▁engineering ▁sh ops ▁for ▁four - eng ined ▁heavy ▁bom ber ▁designs , ▁from ▁February ▁ 1 9 4 3 ▁to ▁April ▁ 2 0 , ▁ 1 9 4 4 . ▁ ▁Development ▁ ▁The ▁first ▁proposal ▁for ▁what ▁would ▁become ▁the ▁He ▁ 2 7 4 ▁started ▁with ▁six ▁air frame ▁orders ▁for ▁what ▁had ▁been ▁known ▁as ▁the ▁He ▁ 1 7 7 H , ▁which ▁were ▁requested ▁from ▁He inkel ▁as ▁early ▁as ▁mid - Oct ober ▁ 1 9 4 1 , ▁all ▁to ▁have ▁four ▁engines ▁in ▁stretch ed ▁production ▁He ▁ 1 7 7 A - 3 ▁fus el ages . ▁The ▁main ▁production ▁version ▁had ▁been ▁length ened ▁by ▁ 1 6 0   cm ▁a ft ▁of ▁the ▁wing ' s ▁trailing ▁edge ▁for ▁better ▁stability ▁and ▁also ▁used ▁for ▁the ▁A - 5 ▁sub type ▁— ▁m ated ▁to ▁longer ▁span , ▁four - eng ined ▁wings . ▁ ▁These ▁proposed ▁aircraft ▁were ▁shortly ▁there after ▁officially ▁given ▁the ▁air frame ▁project ▁number ▁ 8 - 2 7 4 ▁by ▁the ▁R LM ; ▁due ▁to ▁the ▁busy ▁He inkel ▁factory ▁design ▁offices ▁and ▁aircraft ▁manufact uring ▁facilities , ▁this ▁new ▁" He ▁ 2 7 4 " ▁high - alt itude ▁bom ber ▁was ▁to ▁have ▁its ▁pro tot ypes ▁built ▁in ▁France ▁by ▁the ▁Soci ete ▁des ▁Us ines ▁Far man ▁( F ar man ▁Brothers ) ▁in ▁S ures nes . ▁Two ▁He ▁ 2 7 4