Te rererangi hua, whakakitea i runga i 28 Hānuere 1971, pānuitia he taimaha mōrahi o 40,000 pauna (18,144 kg) me te tere mōrahi o Mach 2, engari whakaongaonga iti te hiahia i roto i ngā kaihoko ke. Ko te tauira tuatahi (tau rangatū 72-156 mph9) i whakarewahia i Hawthorne i runga i 4 Aperira 1974; tae mai tona rere tuatahi i Edwards AFB i runga i 9 Pipiri ki "Hute" Henry Choute i te mana rere mo 61 meneti tae atu ki te teitei o 18,000 waewae, me te tere mōrahi o 610 haora, e whakarei ake maneuverability. Northrop kihai i ano whakawhirinaki i roto i te rere-i-waea mana, me te puritia mana rere mechanically-tohu. te tauira rererangi, whakakitea i runga i 28 Hānuere 1971, pānuitia he taimaha mōrahi o 40,000 pauna (18,144 kg) me te tere mōrahi o Mach 2, engari whakaoho iti te hiahia i roto i ngā kaihoko ke.
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