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F-111 Aardvark: America’s Multirole Death Machine

Written by Matthew Copes

When General Dynamics’ powerful F-111 first took to the skies in December of 1964, it was touted as one of the world’s most lethal and well-rounded military aircraft.

https://flic.kr/p/W9f5Fj

That said, not everyone believed the hype. 

Since the early ‘60s Defense Secretary Robert McNamara had pushed the F-111 as a multi-role, cross-service platform that could be used by the Air Force, Navy and Marines.

At least in the early going, the result was a franken-plane that wasn’t particularly good at any of the roles for which it had been built.

Tipping the scales at over 110,000 pounds (49,900 kg) when fully decked out for battle, F-111s were far too heavy to outmaneuver smaller fighters or stand up to the rigors of carrier takeoffs and landings.

Unsurprisingly, the Navy wanted nothing to do with its F-111B variant, and it was ultimately canceled long before production was scheduled to begin.

On the other hand, the Air Force had much better luck.

In fact, its F-111s were blisteringly fast and highly successful reconnaissance aircraft, missile jammers and deep penetration bombers, the latter of which could haul massive weapons loads at treetop level, day and night, in nearly all weather and deliver devastating payloads with legendary accuracy.

Background

Between the late ‘50s and early ‘60s both the Navy and Air Force were in the market for new jets to fill various roles.

The former needed a high-speed, long-range interceptor to protect its carrier battle groups against anti-ship missiles launched from Soviet subs and bombers.

Meanwhile, the Air Force set its sights on a versatile aircraft that could carry out fighter, ground attack and deep interdiction missions.

Both services already had capable aircraft, but they were rapidly becoming obsolete, and ex-Ford Motor Company CEO Robert McNamara sought to trim waste and redundancy by commissioning a new place that would, as the old saying goes, be everything to everyone.

Hence, the now infamous Tactical Fighter–Experimental (TFX) design competition was launched in late 1961.

https://commons.wikimedia.org/wiki/File:United_States_Air_Force_-_General_Dynamics_FB-111A_Aardvark_fighter-bomber_plane_2_(43464827144).jpg

At the time, it was poised to be the most expensive weapon system in US history, and top manufacturers like Boeing, Lockheed, General Dynamics and North American Aviation were eager to get their piece of the action.

After a lengthy process of design submissions and evaluation, McNamara and the RAND Corporation “Whiz Kids” ultimately chose General Dynamics’ proposal over vociferous objections from members of the Military Selection Board.

In many respects, other other manufacturer’s designs were at least as good, but General Dynamics’ F-111 stood out for one big reason.

At least in theory, it offered far greater cost-saving commonality between the Navy and Air Force variants.

But though he was never well liked by either branch, McNamara subsequently committed the ultimate sin – at least according to the Navy – by putting the Air Force in charge of the project.

This meant that it would have the upper hand in getting what it wanted put into the aircraft first, while in all likelihood the Navy would have to grudgingly accept a plane that had been built for a rival service.

Yet despite this glaring point of contention, the Air Force and Navy were able to agree on a few basic design elements.

Both variants would have two engines, two crewmen, a unique side-by-side seating arrangement and variable geometry wings.

In some respects, the timing couldn’t have been better. 

Until Francis Gary Powers’ U2 was downed by a surface-to-air missile over the Soviet Union in 1960, the Air force had been relatively confident in its high-flying but subsonic B-47 bombers.

But now, new Soviet SAMS could reach at least 60,000 feet (18,000 m), and possibly much higher.

As a result, B-47s became obsolete almost overnight.

Thankfully, the new Soviet missiles had one fatal flaw – they weren’t nearly as effective at targeting fast, low flying aircraft.

Hence, high subsonic or even supersonic low-level penetration were seen as feasible alternatives.

The Defense Department prioritized new aircraft that would be capable of penetrating Soviet air defenses at high speeds and very low altitudes and operating from short, unfishished runways in remote areas.

Design and Performance

F-111s are most well-known for their variable geometry wings which were incorporated to compensate for the plane’s enormous weight while providing improved performance at various speeds and altitudes.

https://flic.kr/p/QAD9UK

Wings could be swept between 16 and nearly 73 degrees, and when fully extended surface area nearly tripled. 

Conversely, when swept back into the delta configuration, the reduction in drag made high supersonic speed flight possible, albeit at the expense of maneuverability.

Likewise, variable geometry wings allowed for heavier fuel and weapons loads, longer ranges, and short takeoffs and landings.

On the downside, the wings were far heavier, more complex and prone to mechanical failures than traditional fixed wings.

To compensate for this added weight, F-111 airframes included aluminum, titanium and lightweight steel alloy components.

Due to technical difficulties associated with side-by-side seating, F-111s weren’t equipped with ejection seats.

Instead, in emergencies both pilots were jettisoned upward away from the aircraft in unison, in an enclosed one-piece crew capsule.

Power to push the heavy machines to more than twice the speed of sound came from two massive Pratt & Whitney TF30 afterburning turbofans, each of which produced about 18,000 pounds of dry thrust, and more than 25,000 pounds with the afterburners lit.

The Air Force’s F-111A prototype was unveiled in the fall of 1963, but the maiden flight wouldn’t take place until late December of the following year at Carswell Air Force Base in Fort Worth, Texas.

https://flic.kr/p/fuvc46 General Dynamics FB-111A Aardvark (sn 63-9783) prototype.

Since General Dynamics had limited experience building carrier-based aircraft, it continued to work with Grumman on the Navy’s B variant, which ultimately made its first flight in the spring of 1965. 

Both variants had a number of technical problems, one of which was compressor stall issues caused by inefficient engine inlets.

This issue was largely solved by improving airflow with NASA’s help, and the F-111A achieved a speed of Mach 1.3 (997 mph – 1,605 km/h) in February 1965.

However, hairline cracks began appearing in various airframe components during ground fatigue testing, especially where the wings attached to the fuselage.

After years of poor test results and comprehensive design changes, the Navy ultimately canceled its B variant in 1968, while development and testing of the Air Force’s A-model continued into 1973. 

F-111s were nearly 74 feet (23 m) long from nose to tail, and with their wings fully swept wingspan was just 32 feet (9.8 m).

With maximum speeds approaching Mach 2.5 (1,650 mph – 2,656 km/h), F-111s were among the fastest aircraft of the day, excluding MiG 25s and SR-71 Blackbirds.

Weapons and Electronics

F-111s featured internal weapons bays capable of accommodating two 750-pound (340 kg) conventional bombs or one tactical nuclear bomb.

https://jenikirbyhistory.getarchive.net/media/grumman-general-dynamics-f-111b-151973-during-phoenix-missle-tests-mfr-via-7f1416

For defense and attacking ground targets, most variants were equipped with M61 20 mm rotary cannons and more than 2,000 rounds of ammunition.

Had they gone into production, the Navy’s B variants would have carried air-to-air and air-to-surface missiles externally and in their weapons bays, giving them exceptional standoff capabilities even from long ranges.

C and F variants were equipped with Pave Tack targeting systems that were housed in rotating pods in the weapons bay when not in use.

Each Pave Tack unit featured a camera, a laser designator and rangefinder and a Forward Looking Infrared Sensor (FLIR), all of which allowed F-111s to not only find targets, but to take them out with amazingly accurate laser-guided munitions.

Air Force variants were generally equipped with AN/APQ-113 attack and AN/APQ-110 terrain-following radars for weapons deployment and navigation.

Ordnance carried externally was stored on four pylons on each wing.

But though pylons are stationary on traditional aircraft, on F-111s the inner two pylons rotated to keep missiles and bombs parallel to the fuselage when the wings were moving.

All told, between internal weapons bays and external pylons, F-111s could carry more than 30,000 pounds (13,600 kg) of munitions, but since the fixed pylons could not be used with the wings in the fully swept position, combat loads were generally much lighter.

Even so, one F-111 could carry the bomb load of two and a half McDonnell Douglas F-4 Phantom IIs.

Operational history

The first production F-111s were delivered to Nellis Air Force Base in Nevada in mid-July of 1967.

These aircraft were initially used exclusively for crew training, and the first units equipped with F-111s didn’t achieve operational status until almost a year later.

After preliminary testing, six F-111s from the 474th Tactical Fighter Wing were sent to Vietnam in March of 1968, where they underwent additional real-world evaluation. 

More than four dozen night missions were flown during the deployment.

But though the F-111s proved effective against stubborn targets in the north, three aircraft and crews were lost in the early going, and it was never determined whether they were downed by enemy aircraft, surface-to-air missiles, AAA fire or mechanical issues.

Based on the losses, combat operations were temporarily halted two months later.

However, routine inspections turned up serious problems with the wings’ hydraulic systems.

Later, it was determined that these issues alone may have been to blame for at least some of the losses, especially since they were present on most of the F-111s in Southeast Asia.

An aerial left side view of an F-111 aircraft dropping 24 Mark 82 low-drag bombs over the Nellis Air Force Base range. The aircraft is assigned to the 391st Tactical Fighter Training Squadron, 366th Tactical Fighter Wing. https://nara.getarchive.net/media/an-aerial-left-side-view-of-an-f-111-aircraft-dropping-24-mark-82-low-drag-208ca9

Due to this and other issues that required immediate attention, most F-111s were out of service until the fall of 1972.

Those that had been upgraded were eventually restationed at Takhli Air Base, where nearly four dozen took part in operations Linebacker and Linebacker II, primarily flying low-level penetration missions.

Thanks to their revolutionary all-weather terrain following radars, F-111’s often flew as low as 200 feet (61 m) at 550 miles per hour (890 km/h).

Because of their distinctive engine sounds and lethal accuracy, North Vietnamese soldiers nicknamed them “Whispering Death.”

They were difficult targets for gunners on the ground, but at such high speeds and low altitudes there was little room for error.

To make sure they lived to fight another day, F-111 crews generally abided by the following mottos:

“Speed is life,” and “one pass, then haul ass.”

F-111s also carried out bombing missions over neutral Cambodia in support of Khmer Republic forces in early 1973, though these actions ceased with the signing of the Case–Church Amendment.

Officially, F-111s flew more than 4,000 combat missions in Southeast Asia, with only six losses directly attributable to enemy action.

After the war in Vietnam, Aardvarks wouldn’t see action again until Operation El Dorado in 1986, when more than two dozen aircraft carried out strikes against Libyan targets.

It was during this operation that 18 F-111s flew what would become the longest combat mission in history.

Taking off from RAF Lakenheath and RAF Upper Heyford, two flights of F-111s joined up before making the 6,400-mile (10,300 km) round-trip between the UK and Libya.

Averaging just less than 500 miles per hour (804 km/h), the mission took approximately 13 hours and resulted in one aircraft lost somewhere over the Mediterranean, likely to an enemy fighter.

Air Force F-111s also played significant roles in Operation Desert Storm in 1991, during which they had far higher success rates than any other similar aircraft.

More than 60 F-111s took part in the operation and collectively dropped 80% of all bomb tonnage, usually with devastating results.

All told, F-111s were credited with destroying more than 1,4000 tanks and armored vehicles, almost exclusively with laser-guided munitions. 

But though F-111s were in service for more than three decades between the late ‘60s and late ‘90s, they weren’t officially christened “Aardvarks” because of their resemblance to the long-nosed African anteaters, until the Air Forces retirement ceremony in the summer of 1996.

Australian Belly Landing

Of the two dozen F-111s ordered by Australia in 1963, the first wouldn’t enter service with the RAAF until December of 1973. 

Right side view of an Australian F-111 fighter aircraft taking off during PITCH BLACK 84, a joint US, Australian and New Zealand exercise. https://nara.getarchive.net/media/right-side-view-of-an-australian-f-111-fighter-aircraft-taking-off-during-pitch-7f3169

The RAAF bought both bomber and reconaissance variants, the most famous of which was a C-model that experienced a serious in-flight issue that required a less than conventional landing in the summer of 2016.

Shortly after takeoff from RAAF Base Amberley, the plane’s port-side main landing gear actually fell off.

The tower immediately alerted rookie airmen Flying Officer Peter Komar and navigator Flight Lieutenant Luke Warner of the pressing problem.

For the next two hours planners decided the best course of action without having the crew eject and destroying the multi-million dollar aircraft, after which it was determined that the best course of action was to have the crew dump excess fuel and attempt a belly landing using the built-in tailhook to decelerate quickly. 

Though not identical to those on carrier-based aircraft, F-111 tailhooks were used to anchor them to the ground while performing engine tests.

Making the approach, the crew left the working landing gear components in the “up” position so the plane would have a relatively smooth surface on which to land.

On the ground, crews strung a tensioned cable across the tarmac, and as the plane touched down the hook miraculously snagged it on the first pass.

In a hail of sparks and screeching metal, the plane just a few hundred feet before coming to a full stop. 

Due to the likelihood of severe structural damage, the aircraft was never repaired, but both pilots survived with only minor injuries.

Despite the mishap, In 1992 the Australian Government decided to purchase 18 ex-US Air Force F-111s to extend their aircraft’s service lives. 

The RAAF retired its remaining F-111s in December of 2010.


While in service, eight Australian Aardvarks had been lost in crashes with ten fatalities. 

https://commons.wikimedia.org/wiki/File:F-111_Refueling_(9633484740).jpg

End

F-111s were the first production aircraft equipped with variable geometry wings, and they were the first production to have variable geometry wings.

While in service they were joined by other well-known swing-wing aircraft like Soviet MiG-23 “Floggers,” Tupolev Tu-22M “Backfires,” Panavia Tornados, Rockwell B-1 Lancers, and of course the only aircraft ever to be named after Tom Cruise – the iconic F-14 Tomcat.

Despite interservice rivalry, cost overruns and other development issues, F-111s would go on to establish the best safety record of all Century Series Fighters.

In addition to variable geometry wings, F-111s pioneered afterburning turbofan engines, state-of-the-art target acquisition systems and terrain-following radars that allowed them to fly lower and faster and deliver their payloads more accurately than any other aircraft in their class.

In fact their legacy is nothing short of amazing considering that before production began veteran test pilot George Marrett called the F-111 the worst aircraft he’d ever flown.

Ultimately F-111s were replaced by F-15 E Strike Eagles for for medium-range precision strike missions, while the supersonic bomber role has been assumed by the B-1B Lancer.

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