He ▁ 1 7 7 H " ▁specification ▁for ▁a ▁high - alt itude ▁He inkel - des igned ▁heavy ▁bom ber ▁had ▁emer ged ▁from ▁the ▁proposed ▁A - 2 ▁and ▁A - 4 ▁couple d - engine ▁designs , ▁with ▁the ▁intent ▁of ▁carrying ▁a ▁ 2 , 0 0 0   kg ▁( 4 , 4 1 0   lb ) ▁bomb load ▁over ▁a ▁maximum ▁range ▁of ▁some ▁ 3 , 0 0 0   km ▁( 1 , 8 9 5   mi ), ▁and ▁accepted ▁by ▁the ▁R LM ▁for ▁the ▁first ▁time ▁since ▁the ▁re jection ▁of ▁Dr . ▁He inkel ' s ▁initial ▁November ▁ 1 9 3 8 ▁request ▁for ▁two ▁of ▁the ▁early ▁He ▁ 1 7 7 ▁V - series ▁prototype ▁air frames ▁to ▁get ▁them , ▁an ▁individual ▁four - engine ▁installation ▁was ▁being ▁considered ▁for ▁any ▁He   1 7 7 - based ▁bom ber ▁air frame , ▁with ▁a ▁quart et ▁of ▁either ▁B MW ▁ 8 0 1 ▁or ▁DB ▁ 6 0 3 ▁unit ized - install ation ▁engines ▁— ▁the ▁DB ▁ 6 0 3 ▁power pl ants ▁being ▁unit ized ▁in ▁a ▁He inkel ▁factory - specific ▁design ▁also ▁used ▁for ▁the ▁He ▁ 2 1 9 ▁— ▁among ▁the ▁choices ▁of ▁power pl ants ▁being ▁specified , ▁with ▁the ▁same ▁sort ▁of ▁reduced - arm ament ▁def ensive ▁weapon ▁format ▁as ▁the ▁A - 2 ▁and ▁A - 4 ▁were ▁intended ▁to ▁have .