The FB-111A is a medium-range, strategic bomber. A variation of the F-111A tactical fighter, it is the first aircraft to combine the maneuverability of a fighter with the payload and range of a bomber. It can carry both nuclear and conventional weapons.
While the FB-111A fuselage is essentially the same as that of the F-111A, the bomber's wings are slightly longer than those of the fighter. The bomber also has strengthened landing gear and increased braking capacity.
Variable-sweep wings are an important feature of the aircraft. By moving the wings to different positions, a pilot can fly the FB-111 from slow approach speeds to supersonic speed at sea level, and to more than twice the speed of sound above 60,000 feet. The pilot changes the wings' angle in flight or on the ground by moving a lever on the left panel of his cockpit. The lever controls hydraulic actuators that push the wings back by extending large internal screws or contracting the screws to pull the wings forward. Wing angles from 16 degrees (full forward) to 72.5 de-grees (full rear sweep) are possible. When wings are fully swept in what is called the "delta" position, the tips rest close to the horizontal stabilizers. Wings in full forward position give maximum surface area and lift for short takeoff and landing.
The crew of two sit side-by-side in an air-conditioned, pressur-ized cockpit module. The module serves as an emergency escape vehicle and survival shelter on land or water. If ejection is neces-sary, both crew members remain in the cockpit. An explosive cutting cord separates the module from the fuselage and a rocket motor propels it away from the aircraft. The module descends by parachute. Airbags cushion impact and keep the aircraft afloat if it lands in water. The module can be released at any speed and altitude--even under water.
External ordnance and fuel tanks can be carried on six pylons under the wings. On each side, the two pylons nearest the fuse-lage pivot as the wings sweep back, keeping the ordnance parallel to the fuselage. The outer attachment on each wing, used only in subsonic flight, does not pivot and is jettisoned before the wings can be swept past 26 degrees.
A radar bombing system is used for precise weapons delivery during the day, at night, or in bad weather. The automatic terrain-following radar system flies the FB-111 at selectable heights fol-lowing the earth's contours. TFR guides the aircraft into valleys and over mountains, day or night, regardless of weather conditions. Should any of the radar system's circuits fail, the aircraft automati-cally climbs to a safe altitude.
The first production FB-111A was delivered in October 1969 to the 340th Bombardment Group at Carswell Air Force Base, Texas.
Primary function: medium-range strategic bomber
Prime contractor: General Dynamics Corp.
Power plant/manufacturer: two Pratt and Whitney TF30-P-7 turbofan engines with variable afterburners
Thrust: 20,350 pounds each engine
Dimensions: wingspan--spread 70 feet, fully swept 33 feet 11 inches, length 73 feet 6 inches, height 17 feet 1 inch
Speed: Mach 2.5 at 36,000 feet
Ceiling: above 60,000 feet
Range: 4,100 miles with external fuel tanks
Ordnance: up to four AGM-69A SRAM air-to-surface missiles on external pylons and two in weapons bay, or six nuclear bombs, or combinations of these weapons; provision for up to 31,500 pounds of conventional bombs
Crew: two-pilot and navigator-bombardier
Maximum takeoff weight: about 100,000 pounds