Northrop ejighi obi ike na njikwa ụgbọ elu site na waya wee jigide njikwa ụgbọ elu na-egosi na ọ na-efe efe. Mgbe ụgbọ elu nke a rụpụtara, kpughere na 28 Jenụwarị 1971, kwupụtara oke ibu nke 40,000 lb (18,144 kg) na oke ọsọ nke Mach 2, mana ọ kpalitere mmasị dị nta n'etiti ndị na-azụ mba ọzọ. Ejiri prototype mbụ (nọmba usoro 72-156 mph) na Hawthorne Fighter na 4 Eprel 1974; ụgbọ elu mbụ ya na Edwards AFB bịara na June 9 na Henry "Hute" Choute na njikwa na-efe efe maka nkeji 61 na-eru elu nke 18,000 ụkwụ na ọsọ ọsọ nke 65,000 kilomita. Site na njikwa ụgbọ elu nke abụọ, ndị na-anya ụgbọelu YF-17F kwupụtara na YF-17F nwere ike ịrị elu ruo ihe karịrị kilomita iri atọ na ise. Site n'elu elu nke abụọ, ụgbọ elu YF-17F nwere ike ịgba ọsọ ọsọ nke ihe karịrị kilomita iri isii na ise. Mgbe mbụ, ndị na-anya ụgbọelu kwuru na YF-17F nwere ike ịgba ọsọ ọsọ ọsọ nke elu
Ọgọst 21