F-111 Aardvark

The F-111 Aardvark is a medium-range bomber, reconnissance and strike aircraft built by General Dynamics. It was retired by the US Air Force in 1998 but still remains in service with the Royal Australian Air Force (RAAF).

With its swing wings, the F-111 can take off slowly and fly fast from unprepared airfields with a large payload of bombs over long ranges, drop bombs on ground targets and shoot down enemy aircraft with long-range air-to-air missiles. But it was the F-4 Phantom fighter that was a better demonstrator at how versatile a multirole fighter could be as a bomber, dogfighter and reconnaissance platform in three services and many nations. The F-111 demonstrated the inflexibility of a heavy fighter, however it pioneered many new technologies such as the crew escape capsule, swing wings with consequent moving weapon pylons, supersonic turbofan engines, terrain following radar and digital electronics. The F-111 was very successful in the role of a strike aircraft.

The F-111 has been replaced in United States service by the F-15 Eagle, F-16 Fighting Falcon, F-15E Strike Eagle and B-1B Lancer. The Royal Australian Air Force still operates the F-111, however the RAAF is planning to replace their F-111 fleet with the F-35 Joint Strike Fighter.

The F-111 began as the TFX, a 1960s project to combine the US Air Force's need for a fighter-bomber with the US Navy's need for a long-range carrier defense fighter. The fighter design philosophy of the day concentrated on very high speed, raw power, and air-to-air missiles.

The US Air Force's Tactical Air Command (TAC) was largely concerned with the fighter-bomber and deep strike/interdiction role, which in the early 1960s still focused on the use of nuclear weapons. The new plane would be a follow-up to the F-105 Thunderchief, which was designed to deliver nuclear weapons low, fast and far.

Air combat would be an afterthought until encountering MiG fighters over Vietnam in the mid 1960s. In June 1960 the Air Force requested a long-range interdiction/strike aircraft able to penetrate Soviet air defenses at very low altitudes and very high speeds to deliver tactical nuclear weapons against crucial Soviet targets like airfields and supply depots. Included in the request were a low-level speed of Mach 1.2, a high-altitude speed of Mach 2.5, a combat radius of 890 miles (1,430 km), good short-field performance, and a ferry range long enough to reach Europe without refuelling.

At the same time the US Navy was searching for a long-range, high-endurance interceptor to defend its carrier battle groups against Soviet jet bombers, as it had been doing since 1957. Soviet bombers were then armed with anti-ship missiles with nuclear warheads that could easily sink an aircraft carrier. The Navy needed a Fleet Air Defense (FAD) aircraft with better performance and load-carrying ability than the F-4 Phantom that would be equipped with a powerful radar and long-range air-to-air missiles to intercept both bombers and their missiles.

The Navy had considered a slow straight-winged missile carrier, the F-6D Missileer, but had rejected it. In December 1960 the Navy had been reconsidering variable geometry for the FAD requirement. The trend toward ever bigger, more powerful fighters posed a problem for the Navy: the current generation of naval fighters were already barely capable of landing on an aircraft carrier, and a still larger and faster fighter would pose even greater problems. An airframe optimised for high speed - most obviously with a high-angle swept wing - is inefficient at cruising speeds, which reduces range, payload, and endurance, and leads to very high landing speeds.

On the other hand, an airframe with a straight or modestly swept wing, while easier to handle and able to carry heavy loads over longer distances on a minimum of fuel, has lower ultimate performance. Variable geometry, which the Navy had tried and abandoned for the XF10F Jaguar in 1953, offered the possibility of combining both in a single airframe.

The newly appointed Secretary of Defense Robert McNamaram, the former President of the Ford Motor Company, was a great believer in "commonality" - using a single versatile platform instead of several fighters specialized for each service would lead to large cost savings. He had already directed the Air Force to adopt the highly successful F-4 Phantom and A-7 jets.