General Dynamics F-111

The General Dynamics F-111 Aardvark (the nickname was unofficial for most of its lifespan, but it was officially named "Aardvark" at its retirement ceremony for the United States Air Force) is a long-range strategic bomber, reconnaissance, and tactical strike aircraft. The F-111 project was long considered an expensive failure, but the end result was a capable, albeit costly, aircraft.

Variants

F-111A

The F-111A was the initial production version of the F-111. It had TF30-P-3 engines with 12,000 lbf (53.38 kN) dry and 18,500 lbf (82.29 kN) afterburning thrust and "Triple Plow I" variable intakes, providing a maximum speed of Mach 2.2 (1,453 mph / 2,325 km/h) at altitude.

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The -A's Mark I avionics suite included the General Electric AN/APQ-113 attack radar mated to a separate Texas Instruments AN/APQ-110 terrain-following radar under the nose and a Litton AJQ-20 inertial navigation and nav/attack system.

Related Topics:
Avionics - General Electric - Radar - Texas Instruments - Terrain-following radar - Litton - Inertial navigation

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Total production of the F-111A was 158, including 17 preproduction aircraft that were later brought up to production standards.

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The first production F-111s were delivered on 18 July, 1967 to the 428th, 429th and 430th Tactical Fighter Squadrons of the 474th Tactical Fighter Wing based at first out of Cannon AFB, New Mexico, which relocated in 1968 to Nellis AFB.

Related Topics:
18 July - 1967 - 474th Tactical Fighter Wing - Cannon AFB - New Mexico - 1968 - Nellis AFB

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After early testing a detachment of six aircraft were sent in March 1968 to Southeast Asia for Combat Lancer testing in real combat conditions in Vietnam. In little over a month, three aircraft were lost and the combat tests were halted. It turned out that all three had been lost through malfunction (primarily with the terrain-following radar), not by enemy action. This caused a storm of political recrimination, with U.S. Senators denouncing Secretary of Defense McNamara's judgment in procuring the aircraft.

Related Topics:
1968 - Vietnam

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Behind the scenes, lessons were being learned and fixes being applied, but it was not until July of 1971 that the 474 TFW was fully operational. Testing in 1969 had revealed that a contractor had been paying off inspectors to approve sub-standard work on structural wing components, and all aircraft had to have the component replaced at significant cost (since most F-111As had been already completed). More failures were found and corrected in the wing pivot forgings.

Related Topics:
1971 - 1969

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1972 saw the F-111 back in Vietnam, participating in the Linebacker II aerial offensive against the North. F-111 missions did not require tankers nor ECM support, and they could operate in weather that grounded most other aircraft. One F-111 could carry the bomb load of four F-4 Phantom IIs. The worth of the new planes was beginning to show, and over 4,000 combat F-111A missions were flown over Vietnam with only six combat losses.

Related Topics:
1972 - Linebacker II - F-4 Phantom II

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In 1977 the remaining F-111As were transferred to the 366 TFW based at Mountain Home AFB, equipping the 389th and 391st TFS.

Related Topics:
1977 - 366 TFW - Mountain Home AFB

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In 1982 four surviving F-111As were converted to F-111C standard and provided to Australia as attrition replacements. They were fitted with the longer-span wings and reinforced landing gear of the -C, and subsequently were almost indistinguishable from new-build F-111Cs. Some of the -As delivered to the RAAF were Vietnam veterans, purportedly still bearing the scars of anti-aircraft fire.

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42 F-111As were converted as the EF-111A Raven for an electronic warfare tactical electronic jamming role. They can be distinguished from other -As by the equipment bulge atop their tails, a featuring leading to the nickname "Fat Tail." The fin-tip pod held the receiving antennae, while the emitters were in a narrow 4.88 metre radome along the underside of the fuselage. The major component was the ALQ-99 tactical jamming system. The total EW package massed 6-8,000 pounds and replaced all weapons systems, with the second crew-member becoming solely concerned with the EW systems. The final twelve Ravens were retired in 1998 when the increased complement of EA-6Bs and the addition of the new Prowler made them finally surplus.

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Three pre-production -As were provided to NASA for various testing duties. One was fitted with a variable-camber wing as part of the Advanced Fighter Technology Integration program in the 1980s; it was retired to the United States Air Force Museum at Wright Patterson AFB in 1989.

Related Topics:
NASA - 1980s - United States Air Force Museum - Wright Patterson AFB - 1989

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Most of the unconverted surviving F-111As were retired in 1992 and mothballed at AMARC, Davis Monthan AFB.

Related Topics:
1992 - Davis Monthan AFB

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F-111B

The F-111B was to be a fleet-defense fighter for the U.S. Navy, fulfilling a long-standing naval requirement for a fighter capable of carrying heavy, long-range missiles to defend carriers from Soviet anti-ship missiles. The F-111B was equipped with the Hughes AN/AWG-9 pulse-Doppler radar and up to six of the new AIM-54 Phoenix long-range air-to-air missiles. General Dynamics, having no experience with carrier-based aviation, partnered with Grumman for this version.

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The F-111B was a compromise that attempted to reconcile the Navy's very different needs with an aircraft whose configuration was largely set by the USAF need for a supersonic strike aircraft, and those compromises were to prove its undoing. The B was shorter than the F-111A, to enable it to fit on carrier lifts, but had a longer wingspan (70 ft/21.3 m compared to 63 ft/19.2 m) for increased range and cruising endurance. Although the Navy had wanted a 48 in (122 cm) radar dish for long range, they were forced to accept a 36 in (91.4 cm) dish for compatibility. The Navy had requested a maximum take-off weight of 50,000 lb (22,686 kg), but Secretary of Defense McNamara forced them to compromise at 55,000 lb (24,955 kg). This proved to be overly optimistic.

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Weight plagued the B throughout its development. Not only were prototypes far over the 55,000 lb limit, efforts to redesign the airframe only made matters worse. The excessive weight made the aircraft seriously underpowered. Worse, its visibility for carrier approach and landing were abysmal, and its maneuverability—especially in the crucial medium-altitude regimen—was decidedly inferior to the F-4 Phantom II.

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By October 1967, the Navy was finally convinced that the F-111B program was a lost cause and recommended its cancellation, which occurred in 1968. The Phoenix missiles and radar developed for this plane (and the earlier, cancelled F6D Missileer) were eventually used on its replacement, the F-14 Tomcat.

Related Topics:
1968 - F-14 Tomcat

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F-111C

The F-111C was an export version for Australia, combining F-111A/E avionics with the long-span wings and heavier landing gear of the F-111B. Twenty-four were originally ordered in 1963, although development delays and structural problems kept them from entering service until 1973.

Related Topics:
1963 - 1973

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Four aircraft were modified to RF-111C reconnaissance configuration, retaining their strike capability.

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The only F-111 model still in service, F-111C aircraft have been equipped to carry Pave Tack FLIR/laser pods, and later underwent an extensive Avionics Upgrade Program, with AN/APQ-169 attack radar replacing the elderly AN/APQ-113, Texas Instruments AN/APQ-171 terrain-following radar, twin Honeywell H423 ring-laser gyro INS, GPS receiver, modern digital databus, mission computer, and stores-management system, and cockpit multi-function displays (MFDs). Their engines were updated to TF30-P-108/109RA standard, with 21,000 lbf (93.4 kN) thrust. Four ex-USAF F-111As were refitted to F-111C standard and delivered to Australia as attrition replacements.

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A series of upgrades has kept the Australian F-111 fleet up to date, and it is planned to keep them in service until about 2010.

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F-111D

The F-111D was an upgraded F-111A equipped with newer Mark II avionics, more powerful engines, improved intake geometry, and an early "glass cockpit." First ordered in 1967, extensive development problems delayed service entry until 1974, and only 96 were built.

Related Topics:
1967 - 1974

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The F-111D used the new Triple Plow 2 intakes, which were located four inches (about 10 cm) further away from the airframe to prevent engine ingestion of the sluggish boundary layer air that was known to cause stalls in the TF30 turbofans. It had more powerful TF30-P-3 engines with 12,000 lbf (53.4 kN) dry and 18,500 lbf (82.3 kN) afterburning thrust.

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More significant--and problematic--were the Mark II avionics. These were digitally integrated microprocessor systems, some of the first used by the USAF, offering tremendous capability, but substantial teething trouble. The main radar was the General Electric AN/APQ-114, with Doppler beam-sharpening, moving-target indicator (MTI), and continuous-wave mode for guiding semi-active radar homing missiles (which the standard AN/APQ-113 set could not). This was matched with an Autonetics inertial navigation/attack radar system, Marconi Doppler radar for navigation, a horizontal situation display, an IBM processor, and a Norden integrated systems display, with modern multi-function displays (MFDs). These last proved to be a major source of trouble, serving to multiply the development problems experienced with the individual systems. Considerable acrimony between the contractors resulted, and it took years before the bugs were worked out. F-111 crews considered the -D the most capable (and user-friendly) version of the aircraft when everything worked, but that was all too rare before the 1980s.

Related Topics:
USAF - Semi-active radar homing - Autonetics - Inertial navigation - Marconi - IBM - Norden - 1980s

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Incidentally, the F-111D was never equipped to carry what proved to be the 'Aardvark's' most useful sensor system, the AN/AVQ-26 Pave Tack pod.

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The F-111D was withdrawn from service in 1992 for mothballing at AMARC.

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F-111E

The F-111E was a simplified, interim model ordered after the prolonged teething troubles of the F-111D. It used the -D's Triple Plow 2 intakes and more powerful TF30-P-3 engines, but retained the -A's Mark I avionics.

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Although conceived after the -D, the F-111E was actually delivered before it. The first flight of an -E was 20 August 1969. A total of 94 were built.

Related Topics:
20 August - 1969

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Some F-111Es were based at RAF Upper Heyford in Oxfordshire (United Kingdom) until 1993, and the type saw service in Operation Desert Storm. All F-111Es were withdrawn to storage in 1993 and 1994.

Related Topics:
RAF Upper Heyford - Oxfordshire - 1993 - Operation Desert Storm - 1993 - 1994

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F-111F

The F-111F was the final F-111 variant produced for Tactical Air Command, with more modern and advanced Mark IIB avionics that were more capable than the F-111E and much more reliable than the F-111D. A total of 106 were produced between 1971 and 1976. The aircraft were mostly assigned to the 48 TFW based at RAF Lakenheath in the United Kingdom, with some assigned to the 57th Fighter Weapons Wing at Nellis AFB.

Related Topics:
Tactical Air Command - 1971 - 1976 - 48 TFW - RAF Lakenheath - 57th Fighter Weapons Wing

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The F-111F's Mark IIB avionics suite used a simplified version of the FB-111A's radar, the AN/APQ-144, lacking some of the strategic bomber's operating modes but adding a new 2.5 mi (4.0 km) display ring. Although it was tested with digital moving-target indicator (MTI) capacity, it was not used in production sets. It used Texas Instruments AN/APQ-146 terrain-following radar, Litton inertial navigation, and the F-111E's Weapon Control Panel. The internal weapons bay was normally occupied by a AVQ-26 Pave Tack FLIR and laser designator system for the delivery of precision laser-guided munitions. The radar was subsequently upgraded to AN/APQ-161, with the AN/APQ-171 terrain-following set. The later Pacer Strike avionics update program added new digital electronics and databus.

Related Topics:
Texas Instruments - Pave Tack - Laser designator

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The -F also used the Triple Plow 2 intakes, along with the substantially more powerful TF30-100 turbofan with 25,100 lbf (111.6 kN) afterburning thrust. This substantially improves the -F's performance, allowing a top speed of Mach 2.5 at altitude and enabling an unloaded F-111F to supercruise (fly at supersonic speeds without afterburner).

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The F-111F made its combat debut in Operation El Dorado Canyon against Libya in 1986, and performed superbly in Operation Desert Storm against Iraq, where it unexpectedly added the anti-armor ("tank-plinking") role to its resume.

Related Topics:
Operation El Dorado Canyon - Libya - 1986 - Tank-plinking

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Various plans to upgrade the F-111F, including the adoption of the General Electric F110 engine (used in the F-14D Tomcat), were proposed, but not implemented because they might have interfered with the USAF's political efforts to build the F-22 Raptor. As a result, the last USAF F-111s were withdrawn from service on 27 July 1996, replaced by the F-15E Strike Eagle.

Related Topics:
General Electric F110 - F-14D Tomcat - F-22 Raptor - 27 July - 1996 - F-15E Strike Eagle

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