Genesis of the F-35 Joint Strike Fighter

greeted with considerable skepticism, largely because the joint Tactical Fighter Experimental (TFX) program of the 1960s had not succeededasajointprogram.TheTFXprogramwasintendedtosave several billions of dollars in life cycle costs by using a common airframe and engines to meet both the Navy’s fleet air defense requirement and the Air Force’s requirement for a long-range fighter bomber. The Navy withdrew from the TFX program when the aircraft became too heavy for carrier operations. The Air Force was left with an F-111 too small to be an effective bomber and not maneuverable enough to be a competitive fighter. In addition, developing a supersonic, vertical takeoff and landing (VTOL) fighter was considered a significant technical challenge by itself. The stages in the evolution of VTOL aircraft are illustrated in Fig.2.The firstattemptstobuildaverticaltakeoffandlanding fighter werethetailsittersofthe1950s,includingtheXFV-1,theXFY-1,and the X-13. Because the thrust-to-weight ratio of fighter aircraft was already close to 1, designers thought that it would be a simple matter of standing a fighter on its tail and increasing the thrust a little to