General Dynamics F-111 Aardvark
| General Dynamics F-111 | ||
|---|---|---|
| A USAF F-111 | ||
| Description | ||
| Role | All-weather attack, all-weather interceptor | |
| Crew | 1 Pilot, 1 Weapons Systems Officer | |
| Dimensions | ||
| Length | 73.5 ft | 22.4 m |
| Wingspan (spread) | 63 ft | 19.2 m |
| Wingspan (swept) | 31.92 ft | 9.74 m |
| Height | 17.08 ft | 5.22 m |
| Wing area (spread) | 657.07 sq ft | 61.07 m2 |
| Wing area (swept) | 525 sq ft | 48.77m2 |
| Weights | ||
| Empty | 47,481 lb | 21,537 kg |
| Loaded | ||
| Maximum take-off | 100,000 lb | 485,360 kg |
| Powerplant | ||
| Engines | 2 Pratt & Whitney TF30-P-100 Turbofans with afterburners | |
| Power | 25,000 lb | 11,340 kg |
| Performance | ||
| Maximum speed | 1,450 mph (Mach 2.2) | 2,335 kph |
| Combat range | ||
| Ferry range | 2,925 mi (F variant) | 4,707 km |
| Service ceiling | 60,000ft | 18,290m |
| Rate of climb | ||
| Armament | ||
| Guns | One M61 gun (optional) | |
| Bombs | Max External: 31,500 lb | Max External: 14,288 kg |
The General Dynamics F-111 (unofficial nickname: "Aardvark") 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.
Development
The F-111's beginnings were in the TFX, an ambitious early 1960s project to combine the USAF requirement for a fighter-bomber with the US Navy's need for a long-range air defence fighter to replace the F-4 Phantom II and the F-8 Crusader. The fighter design philosophy of the day concentrated on very high speed, raw power, and air-to-air guided missiles. (This would change within a few years as experience showed that close-in dogfighting remained important in air combat - guns and an emphasis on agility were reintroduced to fighter design, but only after the F-111 was developed.)
For the US Navy, the trend to ever bigger, more powerful fighters posed a problem: the current generation of naval fighters were already barely capable of landing on an aircraft carrier deck; and a still larger and faster fighter would be more difficult again. An airframe optimised for high speed (most obviously with a high-angle wing sweep) 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 a long way on a minimum of fuel, has lower ultimate performance for combat. It was these considerations that led to the famous F-111 variable geometry, the 'swing-wing'.
The birth of the TFX was marked by controversy, with the Air Force, the Navy and the US Government all pulling the project in different directions. At one stage, it was even planned to use it for the United States Army and the United States Marine Corps as a close support aircraft! Several manufacturers submitted bids; the final two shortlisted were General Dynamics and Boeing. The USAF and the USN, in one of the few matters they were able to agree on, both wanted the Boeing design, but United States Secretary of Defense Robert McNamara overruled them and chose the General Dynamics aircraft instead, citing cost issues—an extraordinary irony considering the eventual price of F-111s!
The design eventually emerged as a 20 tonne aircraft (empty) with a maximum takeoff weight of almost 50 tonnes, powered by two afterburning Pratt & Whitney TF-30 turbofans in the 80 kN class, with side-by-side accommodation for a crew of two. The high mounted wings were attached to a pair of giant swivels, allowing it to take off, land, and loiter with a modest 16 degree sweep (for maximum lift and minimum landing speed), cruise at high sub-sonic speeds with a 35 degree sweep, or rotate the wings right aft to a 72.5 degree sweep for a very fast maximum speed of Mach 2.4—particularly so for a bomber, which the F-111 had become by this time, its "F" (for "fighter") designation notwithstanding.
Production versions of the F-111 did not have ejection seats. The pressurized crew compartment ejected as a self-contained survival module and descended under a 70 foot parachute. The two-man crew could work in 'shirt-sleeves' without pressure suits or oxygen masks.
First flight was in December 1964 and entry into service with the USAF began in 1967. It was the first variable geometry aircraft. Despite its clear advantages, variable geometry remains a relatively unusual feature in military aircraft, due to higher cost, and the extra weight imposed by the swing-wing mechanism. Nevertheless, several other types have followed, including the Soviet Sukhoi Su-17 (1966), MiG-23 (1967) and Tupolev Tu-160 bomber (1981), the US F-14 Tomcat naval fighter (1970) and B-1 bomber (1974), and the European Panavia Tornado (1974).
Service life
The F-111 was in service with the USAF from 1967 through 1998.
F-111A
The first production F-111s were delivered on July 18, 1967 to the 428th, 492nd 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. 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, not by enemy action. This caused a storm of political recrimination, with US Senators denouncing Secretary of State McNamara's judgment in procuring the aircraft.
Behind the scenes, lessons were being learned and fixes being applied, but it was not until July of 1971 that the 474th 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.
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, it was found, could carry the bomb load of four F-4 Phantoms. 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.
In 1977, the remaining F-111As were transferred to the 366th TFW based in Mountain Home, Idaho, equipping the 389th and 391st TFS. Numbers dwindled from that point; 42 aircraft were converted into EF-111A Raven electronic warfare aircraft, and a number were sent to Australia. From the early 1990s planes began to be mothballed at AMARC, Davis Monthan AFB.
F-111B
The F-111B was to be the Navy fighter version of the F-111. General Dynamics, having no experience with carrier-based aviation, partnered with Grumman for this version. The F-111B was severely overweight for carrier use, underpowered, and lacking in range. 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 AN/AWG-8 radar developed for this plane (and the earlier, cancelled F6D Missileer) were eventually used on its replacement, the F-14 Tomcat.
F-111C
Export version for Australia - see below.
F-111D
The F-111D was an upgraded F-111 equipped with newer avionics, more powerful engines, improved intake geometry, and an early "glass cockpit". The newer, more complicated systems gave many problems, and the F-111D was not operationally ready until 1974. The F-111D was withdrawn from service in the very early 1990s to AMARC for mothballing.
F-111E
The F-111E was a simpler F-111 ordered after the prolonged teething troubles of the F-111D, with the F-111D's greater power and improved intakes but without the troublesome electronics. The F-111E was actually delivered before the D-model. Some F-111Es were based at RAF Upper Heyford in Oxfordshire (England) until 1993, and the type saw service in Operation Desert Storm. All F-111Es were withdrawn to storage in 1993 and 1994.
F-111F
The F-111F was the final F-111 variant produced for Tactical Air Command, with more modern and advanced avionics which were more capable than the F-111E and much more reliable than the F-111D. The aircraft were mostly assigned to the 48th TFW based at RAF Lakenheath in England, with some assigned to the 57th Fighter Weapons Wing at McClellan AFB.
In these aircraft, 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.
F-111Fs participated in Operation Eldorado Canyon against Libya in 1996, and in Operation Desert Storm against Iraq. They were withdrawn from service in 1995/1996.
FB-111 strategic bomber
The FB-111 was a strategic bomber version of the F-111 developed as an interim aircraft for the Strategic Air Command to replace the B-58 Hustler and early models of the B-52 Stratofortress. The planned replacement program, the Advanced Manned Strategic Aircraft, was proceeding slowly, and the Air Force was concerned that fatigue failures in the B-52 fleet would leave the strategic bomber fleet dangerously under strength. Although 263 planes were planned originally, the total was finally cut to just 76; the first production aircraft was delivered in 1968.
The FB-111A differed from the F-111A in that it was 2 ft 1.5 in longer to carry additional fuel for greater range, and it was fitted with longer wings (also used on the F-111B) for greater range and load-carrying ability. A stronger undercarriage was needed, and the aircraft had updated electronics.
Armament for the strategic bombing role was the Boeing AGM-69A SRAM, two of which could be carried in the internal weapons bay and two more on the inner underwing pylons. The remaining four wing pylons were used to carry drop tanks to increase the aircraft's range.
Conventional bombs (24 × 750 lbs) or gravity-dropped nuclear weapons could also be carried. In 1990, the SRAM was withdrawn from service amid concerns about the integrity of its nuclear warhead in the case of fire, and subsequently only unpowered bombs were available.
The FB-111 became surplus to SAC's needs after the introduction of the Rockwell B-1 Lancer, and the remaining FB-111s were converted to a tactical configuration and renamed the F-111G. These did not remain in USAF service for long, being mothballed in 1993, but a number were bought by Australia.
EF-111A Raven electronic warfare aircraft
An electronic warfare variant of the F-111, the EF-111A Raven, was developed to replace the outdated Douglas EB-66 in USAF service. The US Navy's Grumman EA-6B Prowler was considered, but the USAF did not want a Navy design. A contract to develop the EF-111A was awarded to Grumman in 1974 to modify F-111 airframes for the new role. The first fully-equipped model flew in 1977 and deliveries to combat units began in 1981, all 42 conversions being delivered by the end of 1985.
The AN/ALQ-99E jamming subsystem's electronics were installed in the weapons bay, while transmitters were fitted in a 16 foot long ventral "canoe" radome. Receivers were installed in a fin-tip pod similar to that of the EA-6B. The aircraft's electrical and cooling systems had to be extensively upgraded to support this.
The cockpit was extensively rearranged, with all flight and navigation displays relocated to the pilot's side, controls being removed from the other seat where the electronic warfare officer's instrumentation and controls were installed.
EF-111s saw combat use during Operation Eldorado Canyon (the 1986 retaliatory attack on Libya) and Operation Desert Storm in 1991, after which a detachment of EF-111s was stationed at Al Kharj Air Base in Saudi Arabia until April 1998.
Shortly afterward, in May 1998, the USAF withdrew the final EF-111As from service, placing them in storage at AMARC. These were the final F-111s in service with the USAF.
Foreign sales
Australia
The Australian government ordered 24 F-111 aircraft in 1963 to replace the RAAF's English Electric Canberra in the bombing and tactical strike role. Originally intended to be identical to USAF F-111As, the F-111C aircraft eventually delivered were a combination of F-111A and FB-111A features - the latter including the eight underwing pylons, longer wings and reinforced undercarriage.
While the first aircraft was officially handed over in 1968, structural integrity problems found in the USAF fleet delayed their entry into service until 1973. Four aircraft were modified to RF-111C reconnaissance models, retaining their strike capability.
A number of ex-USAF aircraft have been delivered to Australia, as attrition replacements and to enlarge the fleet. Four aircraft, modified to F-111C status, were delivered in 1982, while eighteen F-111G aircraft were purchased in 1992 and delivered in 1994. Additional stored USAF airframes are reserved as a spares source.
A series of upgrades has kept the Australian F-111 fleet up to date, and it is planned to keep them in service until at least 2020.
An RAAF F-111C with wings swept fully back doing a dump and burn routine.
United Kingdom
Upon cancellation of the BAC TSR-2, the British government ordered 50 F-111K aircraft in 1967. However, the order was cancelled just over a year later; the reason given was the escalating F-111 price.