'Dark Vark' FB-111A 'Aardvark' | Nuclear Weapons

FB-111 Formation

FB-111A Formation, December 1983

'Dark Vark' FB-111A 'Aardvark'

Nuclear Gravity (Free Fall) Bombs

SRAM (Short Range Attack Missile)


'Super FB-111' (FB-111H)

'Dark Vark' FB-111A 'Aardvark'

In the 1960s the B-58 Hustler, Strategic Air Command's futuristic-looking medium bomber, had a single mission profile: fast, high altitude penetration of enemy airspace. SAC doubled down on that mission profile with the B-70 Valkyrie bomber project - canceled in 1961 and relegated to a flight test program. Fast and low were the new watch words after the shoot down of Gary Power's U-2 in 1960. It was also clear that there would be further advances in surface to air missile technology ahead. Strategic Air Command needed an aircraft that could fly at Mach 2 plus speeds at high altitude and then, critically, perform a supersonic, low level dash to the target. That aircraft turned out to be the FB-111. B-52s remained SAC's long-range bomber deterrent until a suitable replacement appeared. A point that would be more than 20 years in the future when the B-1B started to take over that role.

With the announcement of the FB-111 in December 1965, it was envisioned that SAC would possess a total of 263 FB-111 aircraft (20 of which would be trainers). This total was eventually reduced to only 76 amid the ascendancy of the Inter-Continental Ballistic Missile (ICBM) as SAC's main deterrent and in anticipation of the Advanced Manned Strategic Aircraft (AMSA) project (the B-1 bomber). Bad publicity and cost over runs also 'dinged' the FB-111 program. Initial flight of the General Dynamics FB-111A took place in July 1967, with the first production aircraft delivered in August 1968. Production of the FB-111 lasted for 3 years (August 1968 - June 1971).

Compared to the F-111A/E, each wing saw lengthening by 3.5 ft. (a little over one meter) and the landing gear was strengthened to handle a greater take off weight. It also incorporated more powerful engines with 20,350 lbs (90.52 kN) of thrust each rather than 18,500 pounds (82.29 kN) thrust. New avionics, including a astronavigation system (ANS) accurate to several hundred feet (~ 100 m) were fitted. This system could even work during daylight. For a time before a working global positioning system (GPS) this accuracy was remarkably good and it was needed for transiting regions devoid of navigational cues like the polar route - the shortest path to targets in Russia. Able to carry six 600 US gallon (2270 l) drop tanks to extend range - a configuration that was rarely if ever utilized in active service - the FB-111 still needed additional refueling and basing in certain areas closer to the enemy.

Principal weapons included nuclear gravity bombs, like the B43, B61, and the B83, and Short Range Attack Missiles (SRAMs). Also, 24 conventional bombs could be carried when desired. The SAC paint scheme of dark green and gray led to the unofficial nickname 'Dark Vark' for these planes. For info on a 'Super FB-111' click here


TypeStrategic medium-range bomber
CrewTwo, pilot and navigator (side by side)
ContractorGeneral Dynamics
First Flight30 July 1967
Production76 built between August 1968 and June 1971
PropulsionTwo Pratt & Whitney TF30-P7 afterburning turbofans
Engine thrust20,350 lbs (90.52 kN) thrust each
Weight, empty45,200 lbs (20500 kg)
Weight, basic49,090 lbs (22680 kg)
Weight, combat70,380 lbs (31920 kg)
Weight, max. t/o114,300 lbs (51850 kg)
Wing Span70 ft (21.3 m) (fully extended wings)
Wing Span33 ft, 11 in (10.4 m) (fully swept wings)
Wing Area550.00 sq ft (51 sq m)
Length75 ft 6 in (23 m)
Height17 ft 2 in (5.2 m)
Service Ceiling60,000 ft (18300 m)
Climb rate23,418 ft/min (7140 m/min)
Speed, max.1,675 mph (2700 km/h) (Mach 2.2)
Speed, cruise571 mph (920 km/h)
Range2,920 miles (4700 km) (non-refueled)
WeaponsNuclear gravity bombs, like the B43, B61, and the B83, SRAMs;
up to 24 conventional bombs 1
Weapon load35,500 lbs (16100 kg) in weapons bay and on wing pylons

1 Weapons also included one 20mm M61A1 cannon, usually kept in storage at air bases.

509th Bomb Wing FB-111s

Two 509th Bomb Wing FB-111s

Full Sources

"General Dynamics F-111 Aardvark (Air Vanguard)" by Peter E. Davies. Bloomsbury Publishing. Kindle Edition. 2013

"F-111 Aardvark: General Dynamics' Variable-Swept-Wing Attack Aircraft" by John Gourley. Schiffer Military. 2021

Strategic Air Command (SAC) & Aerospace Museum

March Field Air Museum

The Nuclear Information Project (Federation of American Scientists)

"A Compendium of Armaments and Military Hardware" by Christopher Chant. Routledge & Kegan Paul Books. 1987

"Aircraft Armaments Recognition" by Christopher Chant. Ian Allan Ltd. 1989

"Illustrated Encyclopedia of the World's Rockets and Missiles" by Bill Gunston. Crescent. 1979

Metric values calculated with the help of Convertworld

B43, B61, and B83 Nuclear Gravity (Free Fall) Bombs

B61 nuclear bomb

B61 nuclear bomb

Typethermonuclear bombthermonuclear bombthermonuclear bomb
Intended rolestrategictactical / strategicstrategic
Developed byLASL 1LANL 1LLNL 1
Manufactured4/61 - 10/6510/66 - early 90s6/83 - 1991
Retired(early Mods) began 12/72, last 4/91(early Mods) retired 70s - 80sTo be retired 2
Production1000 (all Mods)3150 (all Mods)650 (all Mods)
Yield70 kT to 1 Megaton(Mod 7) 10 - 340 kilotonslow kT to 1.2 MT
PAL Cat 3(Mod 2) B(Mod 7) DD
Fuzingairburst or contactairburst or contactairburst or contact
DeliveryF/F 4 or retarded, 5 laydown 6F/F 4 or retarded, 5 laydown 6F/F 4 or retarded, 5 laydown 6
Accuracy< 600 ft ? (180 m)< 600 ft (180 m)< 600 ft (180 m)
Parachutes1x4 ft (1.2 m), 1x23 ft (7 m) ribbon 71x17 ft (5 m) or 1x24 ft (7.3 m) ribbon 73x4 ft (1.2 m), 1x46 ft (14 m);
1x5 ft (1.5 m), 1x46 ft (14 m)
Featuresavailable in five yieldsrelease height: low as 50 ft (15 m)
DAY (Dial-A-Yield)
FUFO: Full Fuzing Options
release height: low as 150 ft (45 m)
DAY (Dial-A-Yield)
FUFO: Full Fuzing Options
Weight2,060 - 2,125 lbs (935 - 960 kg)695 - 716 lbs (315 - 325 kg)2,408 lbs (1090 kg)
Length12 ft 6 in - 13 ft 8 in (3.81 - 4.17 m)11 ft 9.5 in (3.59 m) 812 ft 1 in (3.68 m)
Diameter18 in (0.46 m)13.4 in (0.34 m)18 in (0.46 m)

1 LASL (Los Alamos Scientific Laboratory); LANL (Los Alamos National Laboratory); LLNL (Lawrence Livermore National Laboratory).
2 B83 to be retired under the 2022 Nuclear Policy Review.
3 PAL Cat denotes the Permissive Action Link (PAL) Category of the bomb (A - F).
4 F/F (Free Fall).
5 Retarded delivery means a parachute slows down the bomb as it falls, allowing the aircraft to escape the weapon's blast.
6 Laydown is a high / supersonic speed, low-level release over the target.
7 Ribbon parachutes resist ripping and bursting at high / supersonic speeds.
8 B61 length includes tail fins; body length alone equals 10 ft 10.75 in (3.32 m).

data from https://nuclearweaponarchive.org/index.html

For more info on the latest B61 nuclear weapon including its possible use in bunker busting

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Boeing AGM-69 SRAM (Short Range Attack Missile)

The Short Range Attack Missile or SRAM is a rocket propelled air-to-ground missile with a nuclear warhead. It has the great advantage over free fall nuclear bombs of allowing a launch aircraft to standoff and fire at a target rather than overflying it. Considered a replacement for the much larger AGM-28 'Hound Dog' missile, the Boeing Company received an Air Force contract for developing and building the Short Range Attack Missile on 31 October 1966. The first launch of a SRAM took place on 29 July 1969, and it entered service in 1972. A basic inertial guidance system meant an accuracy of approx. CEP 1400 ft (430 m) - adequate considering we're dealing with a ~200 kiloton nuclear weapon. Although primarily intended to take out defensive installations, like SAM sites, the SRAM could also be used against strategic targets. Range of the weapon depended on launch altitude but could be over 100 miles (160 km). It had a maximum speed of Mach 3+ and a weight of about 2,240 lbs (1010 kg). For full specifications click on this link or scroll down.

The weapon has several flight profiles available: semi-ballistic, terrain following by radar altimeter, ballistic pop-up followed by terrain following, and a combination of terrain following and inertial guidance. In addition, any of these flight profiles can factor in pre-set 180 degree course changes. All of this made the SRAM, who's radar cross section (RCS) is already small, even harder to detect and intercept.

B-52G and H models could carry 20 Short Range Attack Missiles, six on each of two wing pylons and eight on a rotary launcher in the aft bomb bay while the FB-111A could haul a maximum of six SRAMs, two in the bomb bay and four on underwing pylons. Finally, the B-1B bomber has the capacity to carry 24 SRAMs internally, using three eight round rotary launchers.

The first B-52 unit to to become operational with the SRAM was the 42nd Bomb Wing (B-52G), Loring AFB, Maine, on 15 September 1972. The 509th Bomb Wing (FB-111), Pease AFB, New Hampshire became the first FB-111 unit operational with the weapon on 1 January 1973. On 20 August 1975, the last of the 1500 SRAMs produced were delivered to SAC's 320th Bombardment Wing, Mather AFB, California.

Concerns about degradation of the rocket propellant inside the SRAMs and lack of a fire resistance pit in its nuclear warhead led to the weapon being withdrawn from service in June of 1990. Work on the AGM-69B, an upgraded AGM-69A with a new Thiokol liquid propellant rocket, was canceled in 1977. Later, in December 1986, Boeing was selected to produce a new SRAM (the AGM-131A SRAM II). Click on the link for more info about the SRAM II or scroll down.

NameSRAM (Short Range Attack Missile)
Typerocket propelled air-to-ground nuclear missile
First Launch29 July 1969
In Service1972 - 1990
Production1500 built
Propulsionone Lockheed SR75-LP-1 two-stage solid-fuel rocket
WarheadW-69 nuclear warhead
Yield170 - 200 kT
Fuzingairburst and contact
GuidanceSinger-Kearfott KT-76 inertial plus terrain-avoidance radar altimeter
Featuresmultiple flight profiles
optional 180 degree course changes can be pre-set
Weight2,240 lbs (1010 kg)
Length14 ft (4.27 m) 1
Diameter17.5 in (0.44 m)
Span3 small tail fins set 120 degrees apart
SpeedMach 2.8 to Mach 3.2
Range100 - 137.5 miles (160 - 220 km) high-altitude launch
35 - 50 miles (55 - 80 km) low-altitude launch
AccuracyCEP 1400 ft (430 m) 2

1 15 ft 10 in (4.83 m) with tail fairing, used to reduce drag when the SRAM is carried externally.
2 CEP stands for Circular Error Probable. a measure of weapon accuracy, often defined as the radius of a circle in which 50% of the weapons fired will impact.

SRAM missiles

SRAM missiles (inert)

Boeing AGM-131A SRAM II

In December 1986 Boeing was tasked with developing a follow on to the Short Range Attack Missile (SRAM). Designated AGM-131A SRAM II, it featured a 200 kiloton W-89 nuclear warhead, digitally-controlled with significant safety features: a Fire Resistant Pit (FRP), the use of Insensitive High Explosives (IHE) and a Permissive Action Link (PAL) D Category. The new SRAM reached full-scale development in 1987. About 2/3 the size of the AGM-69A Short Range Attack Missile, the AGM-131A had an advanced two-pulse solid fuel rocket motor, and improved guidance with a laser ring-gyro inertial navigation system. The airframe, made of mostly composite materials, enhanced the missile's low-observable characteristics (stealth). Although, it was expected to enter service in 1992 the SRAM II was canceled in 1991 as part of an arms control initiative. There were also production problems with the missile's motor, according to a USAF fact sheet.

The Nuclear Information Project (Federation of American Scientists)

"Aircraft Armaments Recognition" by Christopher Chant. Ian Allan Ltd. 1989

SRAM II missile

SRAM II missile at the NMUSAF *

* National Museum of the United States Air Force

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'Super FB-111' (FB-111H)

General Dynamics had been working earlier, on a possible F-111G - a bomber variant of the F-111. This was not pursued with. In the wake of the B-1 program being canceled by President Jimmy Carter on 30 June 1977 there appeared an opening for an aircraft to fill the void. Now the company looked at a stretched and improved version of the FB-111A - the FB-111H.

Powered by two General Electric F-101 30,000 lbs (133.45 kN) thrust afterburning turbofans, 17,000 lbs (75.62 kN) thrust w/o afterburner, this was the same engine that was used with the B-1 bomber. Length went from 75 ft 6 in to 88 feet 2.5 inches, allowing an internal fuel load of 64,574 pounds (29300 kg) and doubling the size of the weapons bay. The wingspan remained the same but maximum sweep back was limited to 60 degrees instead of 72.5 degrees with the FB-111A. This means that a supersonic dash at low level would not be possible, although it still would be traveling at very high subsonic speeds. Max. speed reached Mach 2.5 at altitude and range increased by about 1,200 nm (2220 km). Empty weight rose to 51,832 pounds (23300 kg) and max. t/o weight grew to 140,000 lbs (63500 kg). Also, a maximum inflight weight of 155,000 pounds (70300 kg) could be accommodated. A 43 percent commonality of structure was maintained with the F-111A - F.

A 4-round SRAM rotary launcher or 4 - 5 nuclear bombs fit in the weapons bay, while total payload would have been 15 nuclear weapons. Considered a candidate for a Long Range Combat Aircraft (LRCA), the matter was settled in October 1981 when President Ronald Reagan announced that 100 B-1Bs were to be built.

Artist concept of lengthened, advanced FB-111, 1980

Artist concept of lengthened, advanced FB-111, 1980

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