N'ọnwa Machị afọ 1937, otu ndị na-emepụta ụgbọelu nke Donald Douglas, Jack Northrop, na Ed Heinemann duziri, wepụtara atụmatụ maka ụgbọelu na-agba bọmbụ nke nwere 450 hp (336 kW) Pratt & Whitney R-985 Wasp Junior radial engines arụnyere na nku ubu.A na-eme atụmatụ na ọ nwere ike iburu bọmbụ 1,000 lb (454 kg) na 250 mph (400 km / h). Akụkọ banyere arụmọrụ ụgbọelu sitere na Spanish Civil War gosiri na atụmatụ a ga-adị njọ, ma emesịa kagbuo ya. Ajụjụ: Kedu agha ndị akụkọ sitere?
Agha Obodo Spen