Design studies and delays Although effective, the B-52 was not ideal for the low-level role. This led to a number of aircraft designs known as penetrators, which were tuned specifically for long-range low-altitude flight. The first of these designs to see operation was the supersonic F-111 fighter-bomber, which used variable-sweep wings for tactical missions.Gunston 1978, pp. 12–13. A number of studies on a strategic-range counterpart followed.
Design studies and delays Although effective the B-52 was not ideal for the low-level role This led to a number of aircraft designs known as penetrators which were tuned specifically for long-range low-altitude flight The first of these designs to see operation was the supersonic F-111 fighter-bomber which used variable-sweep wings for tactical missionsGunston 1978 pp 12–13 A number of studies on a strategic-range counterpart followed