Ko te hangarau engine i whakaaro ki te kia taea o te tuku i rua te mana o te turbojets mua, me te pau kotahi-third iti wahie. General Electric i pionie te ariā, engari i tukua ki te whakawhanake i te engine mo te C-5 Galaxy, a kihai i tomo ki te mākete arumoni noa i muri. i mahi hoki Pratt & Whitney i runga i te parau tumu taua, a, i te mutunga o 1966, Boeing, Pan Am ko Pratt & Whitney whakaae ki te whakawhanake i te engine hou, tohua te JT9D ki te mana te 747. i hangaia te kaupapa ki te tikanga hou i huaina tātari rakau hapa, e tukua nga pānga o te kore o te wahi kotahi ki te kia ako ki te whakatau i runga i ona atu pūnaha. ki te whakatutuki i āwangawanga e pā ana ki te haumaru me te addyability, ngā hangarau engine i taea o te tuku i rua te mana o te turbojets mua, me te pau kotahi-third iti rawa wahie. i te mutunga o te tau 1969, kua hoatu te kamupene i te ingoa o te 747 ki te whakawhanake i te pūrere tere tere tere rite ki te tere tere tere
kia taea ai e ia te mahi mai i nga taunga rererangi o mua