Rịba ama amaokwu a dị n'okpuru ma zaa ajụjụ ahụ mgbe e mesịrị n'otu asụsụ ahụ dị ka amaokwu ahụ:  N'afọ 1934, ndị United States Army Air Corps rịọrọ ka e nye ha otu ụgbọelu ga-eji okpukpu abụọ karịa nke Martin B-10, bụ́ nke ka na-abata n'ọrụ dị ka ụgbọelu ndị agha na-eji atụ bọmbụ. Na nyocha na Wright Field n'afọ sochirinụ, Douglas gosipụtara DB-1 ya. Ọ na-asọmpi na Boeing Model 299 (mgbe e mesịrị mepụtara n'ime Boeing B-17 Flying Fortress) na Martin Model 146.  Ajụjụ: Ònye bụ onye asọmpi ha?
Boeing Model 299 (nke e mechara mepụta Boeing B-17 Flying Fortress) na Martin Model 146