Tag Archives: Bomber

19 March 1945

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Pilot Officer P. Martin's Avro Lancaster B Mk.I Special, PB996, YZ-C, releases the 22,000-pound Grand Slam earth-penetrating bomb over teh railway viaduct at Arnsberg, Germany, 19 March 1945. (Imperial War Museum)
Pilot Officer P. Martin’s Avro Lancaster B Mk.I Special, PB996, YZ-C, releases the 22,000-pound Grand Slam earth-penetrating bomb over the railway viaduct at Arnsberg, Germany, 19 March 1945. © IWM (CH 15735)
The Grand Slam bomb drops away from the No. 617 Squadron Lancaster B Mk.I Special, YZ-C, 19 March 1945. (Imperial War Museum)
The Grand Slam bomb drops away from the No. 617 Squadron Lancaster B Mk.I Special, YZ-C, 19 March 1945. © IWM (CH 15374)

19 March 1945: Modified Avro Lancaster B Mk.I Special heavy bombers of No. 617 Squadron, Royal Air Force, attacked the railway viaduct at Arnsberg, Germany, using the 22,000 pound (9,979 kilogram) Grand Slam earth-penetrating bomb. The bomb had been first used just days before, 14 March, against another railway viaduct.

The Grand Slam was the largest and heaviest aerial bomb used during World War II. It was designed by aircraft engineer Barnes Neville Wallis, and was scaled up from his earlier, smaller “Tallboy.” (Wallis also designed the “Upkeep” Special Mine used to attack hydroelectric dams in the Ruhr Valley in 1943.)

The Grand Slam bomb dropped by Flying Officer Martin's Avro Lancaster exploeds underneath the railway viaduct at Arnsberg, Germany. (Imperial War Museum)
The Grand Slam bomb dropped by Flying Officer Martin’s Avro Lancaster explodes underneath the railway viaduct at Arnsberg, Germany. Bomb craters from previous unsuccessful attacks are visible in this RAF photograph. © IWM (CH 15378)

Wallis’ idea was that a very heavy, supersonic bomb could penetrate deep into the earth and detonate, causing an “earthquake” which could destroy nearby heavily protected targets.

Tall Boy and Grand Slam Deep Penetration Bombs (British Explosive Ordnance, Part 1, Chapter 7)

The Grand Slam bomb (officially, “Bomb, D.P., 22,000-lb., Mk I”) was 25 feet, 5 inches (7.747 meters) long and had a maximum diameter of 3 feet, 10 inches (1.168 meters). When fully loaded with the explosive material, Torpex, the bomb weighed 22,400 pounds (10,160 kilograms).

Completed bomb casings for Wallis’ smaller 12,000-pound “Tallboy” deep penetration bomb. The individual weight is stenciled on each casing. (Tyne & Wear Archives)

The bomb case was cast of steel at the Clyde Alloy and Steel Company, Glasgow, Scotland, then, after several days of cooling, machined to its precise shape. The casing made up approximately 60% of the bomb’s total weight. At the nose, the casing had a wall thickness of 7.75 inches (19.685 centimeters).

A "Bomb, Medium Capacity, 22,000 Pounds, lifted by a crane at a Royal Air Force bomb dump. (Imperial War Museum)
A “Bomb, Deep Penetration, 22,000 Pounds”—the Grand Slam—lifted by a crane at a Royal Air Force bomb dump. © IWM (CH 15369)

The bomb case was filled with approximately 9,200 pounds (4,173 kilograms) of molten Torpex, with a 1 inch (2.54 centimeters) topping of TNT. Torpex was an explosive designed for torpedo warheads and depth charges. It was made up of approximately equal quantities of two other explosives, Research Department Formula X (RDX), 42%, and trinitrotoluol (TNT), 40%, mixed with 18% powdered aluminum and wax. The resulting combination was approximately 1.4 times more powerful than TNT alone. About one month was required for the explosive to cool after being poured into the bomb case.

Because of its size and weight, the only Allied bomber capable of carrying the Grand Slam was a specially modified Avro Lancaster B.I Special, flown by No. 617 Squadron, Royal Air Force, “The Dambusters.”

An Avro Lancaster very long range heavy bomber carrying a Gland Slam bomb. (Royal Air Force via Sierra Hotel Aeronautics)

Wallis intended for the Grand Slam to be dropped from very high altitudes so that during its fall, it would go supersonic. The bomb had large fins that were offset 5° to the right of the centerline to cause it to rotate for stability. However, the bombers could not carry it to the planned release altitude, and it was typically dropped from approximately 9,000 feet (2,743 meters). Its very sleek design did allow it to come close to the speed of sound, however, and its stability made it a very accurate weapon. The bomb was capable of penetrating 20-foot-thick (6 meters) reinforced concrete roofs of submarine bases. ¹

Arnsberg railway viaduct following Grand Slam bombing attack.

Barnes Neville Wallis, Esq., M. Inst. C.E., F.R.Ae.S., Assistant Chief Designer Vickers-Armstrongs Ltd., was appointed Commander of the Most Excellent Order of the British Empire (Civil Division), by His Majesty, King George VI, 2 June 1943.

Sir Barnes Neville Wallis C.B.E., was knighted by Her Majesty, Queen Elizabeth II, 13 December 1968.

Sir Barnes Neville Wallis C.B.E.

¹ “The striking velocity of the bomb, when released at an altitude of 16,000 ft. and an air speed of 200 m.p.h., is stated at 1,097 ft./sec., at which speed is has developed a rotational velocity of 60 r.p.m.” —British Explosive Ordnance, Part 1, Chapter 7

© 2019, Bryan R. Swopes

17 March 1947

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North American Aviation XB-45 45-59479 in flight. (U.S. Air Force)

17 March 1947: The prototype of the United States’ first jet-powered bomber, the North American Aviation XB-45 Tornado, 45-59479, made a one-hour first flight at Muroc Army Air Field (later known as Edwards Air Force Base) with company test pilot George William Krebs at the controls.

The photographs below show the XB-45 parked on Muroc Dry Lake. Notice that the windows over the bombardier’s compartment in the nose are painted on.

The North American Aviation XB-45 Tornado was a four-engine prototype bomber. It had a high-mounted straight wing and tricycle landing gear. It was 74 feet, 0 inches (22.555 meters) long with a wingspan of 89 feet, 6 inches (27.279 meters) and overall height of 25 feet, 2 inches (7.671 meters). It had an empty weight of 41,876 pounds (18,995kilograms) and maximum takeoff weight of 82,600 pounds (37,467 kilograms).

North American Aviation XB-45 Tornado 45-59479 parked on the dry lake bed at Muroc Army Airfield, California. (U.S. Air Force)
North American Aviation XB-45 Tornado 45-59479 parked on Muroc Dry Lake. (U.S. Air Force)
North American Aviation XB-45 45-59479 makes a low pass over the runway. (U.S. Air Force)

The three prototypes were powered by four Allison-built General Electric J35-A-4 turbojet engines, installed in nacelles which were flush with the bottom of the wings. The J35 was a single-shaft engine with an 11-stage axial-flow compressor section and a single-stage turbine. The J35-A-4 was rated at 4,000 pounds of thrust (14.79 kilonewtons). The engine’s maximum speed was 8,000 r.p.m. The J35 was 14 feet, 0 inches (4.267 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter, and weighed 2,400 pounds (1,089 kilograms).

The maximum speed of the XB-45 was 494 miles per hour (795 kilometers per hour) at Sea Level and 516 miles per hour (830 kilometers per hour) at 14,000 feet (4,267 meters). The service ceiling was 37,600 feet (11,461 meters).

North American Aviation XB-45 45-59479 as a test bed for rocket assisted take-off, 24 September 1958. (U.S. Air Force)

The production B-45A Tornado was heavier and had better performance. It was operated by two pilots and carried a bombardier/navigator and a tail gunner. It was 75 feet, 4 inches (22.962 meters) long with a wingspan of 89 feet, 0 inches (27.127 meters) and overall height of 25 feet, 2 inches (7.671 meters).

The B-45A had a total wing area of 1,175 square feet (109.2 square meters). The leading edges were swept aft 3° 30′. Their angle of incidence was 3° with -3° 30′ twist and 1° dihedral.

The bomber’s empty weight was 45,694 pounds (20,726 kilograms) and maximum takeoff weight was 91,775 pounds (41,628 kilograms).

Cutaway illustration of the North American Aviation B-45 Tornado showing internal structure and arrangement. (U.S. Air Force)

The B-45A was powered by four General Electric J47-GE-13 turbojet engines. The J47 was an axial-flow turbojet with a 12-stage compressor and single stage turbine. It had a normal power rating of 4,320 pounds of thrust (19.216 kilonewtons) at 7,370 r.p.m.; military power, 5,200 pounds (23.131 kilonewtons) at 7,950 r.p.m. (30-minute limit); and maximum power rating of 6,000 pounds(26.689 kilonewtons) at 7,950 r.p.m., with water/alcohol injection (5-minute limit). The engine was 12 feet, 0.0 inches (3.658 meters) long, 3 feet, 3.0 inches (0.991 meters) in diameter and weighed 2,525 pounds (1,145 kilograms).

The B-45A Tornado had a cruise speed of 393 knots (452 miles per hour/728 kilometers per hour), and maximum speed of 492 knots (566 miles per hour (911 kilometers per hour) at 4,000 feet (1,219 meters). Its service ceiling was 46,800 feet (14,265 meters) and it had a maximum range of 1,886 nautical miles (2,170 statute miles/3,493 kilometers).

The bomb load was 22,000 pounds (9,979 kilograms). (It was capable of carrying the Grand Slam bomb.) Two Browning .50-caliber AN-M3  machine guns were mounted in the tail for defense, with 600 rounds of ammunition per gun.

41 B-45As were modified the the “Back Breaker” configuration, which enabled them to be armed with nuclear weapons.

The B-45 served with both the United States Air Force and the Royal Air Force. 143 were built, including the three XB-45 prototypes.

On 20 September 1948, the first production B-45A-1-NA Tornado, 47-001, was put into a dive to test the airplane’s design load factor. During the dive, an engine exploded, which tore off several cowling panels. These hit the horizontal stabilizer, damaging it. The B-45 pitched up, and both wings failed due to the g load. The prototype had no ejection seats and test pilots George Krebs and Nicholas Gibbs Pickard, unable to escape, were both killed.

George William Krebs

George William Krebs was born in Kansas City, Missouri, 5 March 1918. He was the first of three children of William J. Krebs, an advertising executive, and Betty Schmitz Krebs. He attended Southwest High School, graduating in 1935.

Krebs studied at the Massachussetts Instititute of Technology (M.I.T.) at Cambridge, Massachussetts. He was a member of the Sigma Chi fraternity.

In 1940, Krebs was the owner of a Luscombe airplane distributorship in Kansas City. He had brown hair, blue eyes and a ruddy complexion. He was 5 feet, 9 inches tall (1.75 meters) and weighed 135 pounds (61 kilograms).

George Krebs married Miss Alice Bodman Neal at Kansas City, Missouri, 26 December 1942. They had one son, William John Krebs II, born 1944.

During World War II, Krebs was employed as a test pilot at the North American Aviation, Inc., B-25 Mitchell medium bomber assembly plant at Kansas City, Kansas. Prior to taking over the XB-45 project, he was the chief test pilot at K.C.

North American Aviation B-25 Mitchell medium bombers near completion at the Kansas City, Kansas, bomber plant. (Alfred T. Palmer)
Nicholas Gibbs Pickard

Nicholas Gibbs Pickard was born at Brooklyn, New York, 5 November 1916. He was the second of three children of Ward Wilson Pickard, a lawyer, and Alice Rossington Pickard.

During World War II, Pickard served as a ferry pilot for the Royal Air Force Transport Command.

On 21 January 1944, Captain Pickard married Miss Kathleen Baranovsky at Montreal, Quebec, Canada. They had two daughters, Sandra and Manya.

Following the war, Pickard was employed as a test pilot by North American Aviation.

Nicholas Gibbs Pickard was buried at the Pacific Crest Cemetery, Redondo Beach, California.

The tenth production North American Aviation B-45A-1-NA Tornado, 47-011, in flight. (U.S. Air Force)

© 2019, Bryan R. Swopes

1 March 2003

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Star of Abilene, Rockwell B-1B, 83-0065, after its last flight, 1 March 2003. (U.S. Air Force)
Star of Abilene, Rockwell B-1B 83-0065, after its last flight, Dyess AFB, 1 March 2003. (U.S. Air Force)

1 March 2003: The Star of Abilene, the first operational Rockwell B-1B Lancer supersonic heavy bomber, serial number 83-0065, made its final flight at Dyess Air Force Base, Abilene, Texas. It was delivered to the 96th Bombardment Group, Heavy, Strategic Air Command at Dyess on 7 July 1985, and was retired after 17 years, 7 months, 23 days of service.

83-0065 is preserved at the Dyess Linear Air Park, which displays over 30 airplanes along the main road of the air base, showing a chronological progression of Air Power.

The B-1B is 147 feet, 2.61 inches (44.8719 meters) long, with the wing span varying from 86 feet, 8.00 inches (26.4160 meters) at 67.5° sweep to 136 feet, 8.17 inches (41.6603 meters) at when fully extended to 15° sweep. It is 33 feet, 7.26 inches (10.2428 meters) high to the top of the vertical fin. The bomber’s empty weight is approximately 180,500 pounds (81,873 kilograms). Its maximum weight in flight is 477,000 pounds (216,634 kilograms). The internal payload is up to 75,000 pounds (34,019 kilograms).

Rockwell B-1B 83-0065, Star of Abilene, flies over Dyess Air Force Base, 7 July 1985. (Reporter-News)

The bomber is powered by four General Electric F101-GE-102 turbofan engines, mounted in two-engine nacelles under the wing roots. These are rated at 17,390 pounds of thrust (23.578 kilonewtons) and produce 30,780 pounds (41.732 kilonewtons) with “augmentation.” The engine has two fan stages, a 9-stage axial-flow compressor and a 3-stage turbine. The F101-GE-102 is 15 feet, 0.7 inches (4.590 meters) long, 4 feet, 7.2 inches (1.402 meters) in diameter and weighs 4,460 pounds (2,023 kilograms).

“The Bone” has a maximum speed of Mach 1.2 at Sea Level (913 miles per hour, or 1,470 kilometers per hour). The service ceiling is “over 30,000 feet” (9,144 meters). The Lancer’s maximum range is “intercontinental, unrefueled.”

It can carry up to 84 Mk.82 500-pound (226.8 kilogram) bombs, 24 Mk.84 2,000-pound (907.2 kilogram) bombs or other weapons in three weapons bays. The B-1B was built with the capability to carry 24 B61 thermonuclear bombs, though, since 2007, the fleet no longer has this capability.

100 B-1B Lancers were built between 1983 and 1988. As of May 2018, 62 B-1B bombers are in the active Air Force inventory. The Air Force plans upgrades to the aircraft and plans to keep it in service until 2036.

Star of Abilene, Rockwell B-1B 83-0065, after its last flight, Dyess AFB, 1 March 2003. (U.S. Air Force)
Star of Abilene, Rockwell B-1B 83-0065, after its last flight, Dyess AFB, 1 March 2003. (U.S. Air Force)

© 2019, Bryan R. Swopes

24 January 1961

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Boeing B-52G-75-BW Stratofortress 57-6471, similar to 58-0187. The numeral "3" on the vertical fin and the white cross-in-back square on the top of the fuselage identify this B-52 as a Boeing flight test aircraft. (U.S. Air Force)
Boeing B-52G-75-BW Stratofortress 57-6471, similar to 58-0187. The numeral “3” on the vertical fin and the white cross-in-back square on the top of the fuselage identify this B-52 as a Boeing flight test aircraft. (U.S. Air Force)

24 January 1961: “Keep 19,” a Boeing B-52G-95-BW Stratofortress, serial number 58-0187, of the 4241st Strategic Wing, was on a 24 hour airborne alert mission off the Atlantic Coast of the United States. The bomber was commanded by Major Walter S. Tulloch, U.S. Air Force, with pilots Captain Richard W. Hardin and First Lieutenant Adam C. Mattocks. Other crewmembers were Major Eugene Shelton, Radar Navigator; Captain Paul E. Brown, Navigator; First Lieutenant William H. Wilson, Electronics Warfare Officer; Major Eugene H Richards, Electronics Warfare Instructor; Technical Sergeant Francis R. Barnish, Gunner. It was armed with two Mark 39 thermonuclear bombs, each with an explosive yield of 3–4 megatons.

The B-52 refueled in flight from an air tanker. The tanker’s crew notified Major Tulloch that the B-52’s right wing was leaking fuel. The leak was severe and more than 5,400 gallons (37,000 pounds/17,000 kilograms) of jet fuel was lost in less than three minutes. The B-52 headed for Seymour Johnson Air Force Base in North Carolina.

Boeing B-52G-95-BW Stratofortress 58-0190, the same type as Keep 19. (U.S. Air Force)

As they descended, the unbalanced condition made the bomber increasingly difficult to control. The bomber went out of control and Major Tulloch ordered the crew to abandon the doomed ship. Five crewmen ejected and one climbed out through the top hatch. (Lieutenant Mattocks is believed to be the only B-52 crewmember to have successfully escaped through the upper hatch.)

58-0187 broke apart and exploded. Its wreckage covered a two square mile (5.2 square kilometers) area. Three crewmen, Majors Shelton and Richards, and Sergeant Barnish, were killed.

As the B-52 broke up, its two Mark 39 bombs fell free of the bomb bay. One buried itself more than 180 feet (55 meters) deep. The other’s parachute retarding system operated properly and it touched down essentially undamaged. It was quickly safed by an explosive ordnance team and hauled away.

One of teh two Mk 39 bombs that fell from the B-52 as it broke up near Goldsboro, South Carolina, 24 January 1961.
One of the two Mk 39 bombs that fell from the B-52 as it broke up near Goldsboro, North Carolina, 24 January 1961. The parachute retarding  system had deployed, allowing the bomb to touch down with minimal damage.

Recovery of the buried bomb was very difficult. After eight days, the ordnance team had recovered most of the bomb, including the 92 detonators and conventional explosive “lenses” of the “primary,” the first stage implosion section. The uranium-235/plutonium-239 “pit”—the very core of the bomb— was recovered on 29 January. The “secondary,” however, was never found.

Most of the Mark 39 bomb was uncovered from an excavation at the farm field near Goldsboro, North Carolina. (U.S. Air Force)

The secondary contains the fusion fuel, but it cannot detonate without the explosion of the primary. Although the secondary remains buried, there is no danger of an explosion.

“During a B-52 airborne alert mission structural failure of the right wing resulted in two weapons separating from the aircraft during aircraft breakup at 2,000 – 10,000 feet altitude. One bomb parachute deployed and the weapon received little impact damage. The other bomb fell free and broke apart upon impact. No explosion occurred. Five of the eight crew members survived. A portion of one weapon, containing uranium, could not be recovered despite excavation in the waterlogged farmland to a depth of 50 feet. The Air Force subsequently purchased an easement requiring permission for anyone to dig there. There is no detectable radiation and no hazard in the area.”

An accident of this type, involving the loss of nuclear weapons is known by the military code name BROKEN ARROW. Though official statements were that there was no danger that either of the bombs could have exploded, others indicate that five of the six steps (or six of seven) required for a thermonuclear detonation did occur. Only the aircraft commander’s arming switch had not been activated.

Bomb, Mark 39Y1 Mod 2, P/N 300611-00, serial number 4215, at the National Museum of the United States Air Force. Behind it is a Convair B-36 Peacemaker ten-engine strategic bomber. (U.S. Air Force)

The Mark 39 was a two-stage, radiation-implosion thermonuclear bomb. It was in production from 1957–1959, with more than 700 built. It was fully fused, meaning it could be detonated by contact with the ground, as an air burst, or “lay down”— a series of parachutes would slow the bomb and it would touch down on its target before detonating. This allowed the bomber time to get clear.

The Mark 39 was considered a light weight weapon, weighing 6,500–6,750 pounds (2,950–3,060 kilograms). The bomb’s length was approximately 11 feet, 8 inches (3.556 meters), with a diameter of 2 feet, 11 inches (0.889 meters). The explosive yield of the Mark 39 was 3–4 megatons. (For reference, the 1956 nuclear weapons test at Bikini Atoll, Redwing Cherokee, had a yield of 3.8 megatons.)

Fireball from detonation of TX-15 weapon, Operation Redwing Cherokee, 21 May 1956. (Nuclear Weapons Archive)

The Mark 39 was withdrawn from service in the mid-1960s and replaced with the more powerful Mk 41.

© 2018, Bryan R. Swopes

21 January 1987

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Rockwell B-1B Lancer 85-0073, Wings of Freedom, lands at Ellsworth AFB, South Dakota, 21 January 1987. (U.S. Air Force)
General John T. Chain, Jr., U.S. Air Force
General John T. Chain, Jr., U.S. Air Force

21 January 1987: The first Rockwell International B-1B Lancer was delivered to the 28th Bomb Wing at Ellsworth Air Force Base, South Dakota. The airplane, serial number 85-0073, was named Wings of Freedom. It was flown to Ellsworth by General John T. Chain, Jr., Commander in Chief, Strategic Air Command.

100 B-1B Lancers were built by Rockwell International’s aircraft division at Air Force Plant 42, Palmdale, California, between 1983 and 1988

The Rockwell International B-1B Lancer is a supersonic intercontinental bomber capable of performing strategic or tactical missions. It is operated by a flight crew of four.

The B-1B is 147 feet, 2.61 inches (44.8719 meters) long, with the wing span varying from 86 feet, 8.00 inches (26.4160 meters) at 67.5° sweep to 136 feet, 8.17 inches (41.6603 meters) at when fully extended to 15° sweep. It is 33 feet, 7.26 inches (10.2428 meters) high to the top of the vertical fin. The bomber’s empty weight is approximately 180,500 pounds (81,873 kilograms). Its maximum weight in flight is 477,000 pounds (216,634 kilograms). The internal payload is up to 75,000 pounds (34,019 kilograms).

The bomber is powered by four General Electric F101-GE-102 turbofan engines, mounted in two-engine nacelles under the wing roots. These are rated at 17,390 pounds of thrust (17.355 kilonewtons) and produce 30,780 pounds (136.916 kilonewtons) with “augmentation.” The engine has two fan stages, a 9-stage axial-flow compressor and a 3-stage turbine. The F101-GE-102 is 15 feet, 0.7 inches (4.590 meters) long, 4 feet, 7.2 inches (1.402 meters) in diameter and weighs 4,460 pounds (2,023 kilograms).

“The Bone” has a maximum speed of Mach 1.2 at Sea Level (913 miles per hour, or 1,470 kilometers per hour). The service ceiling is “over 30,000 feet” (9,144 meters). The Lancer’s maximum range is “intercontinental, unrefueled.”

A Rockwell B-1B drops Mk. 82 bombs from its three weapons bays. (U.S. Air Force)

It can carry up to 84 Mk.82 500-pound (226.8 kilogram) bombs, 24 Mk.84 2,000-pound (907.2 kilogram) bombs or other weapons in three weapons bays. The B-1B was built with the capability to carry 24 B61 thermonuclear bombs, though, since 2007, the fleet no longer has this capability.

100 B-1B Lancers were built between 1983 and 1988. As of May 2018, 62 B-1B bombers are in the active Air Force inventory. The Air Force plans upgrades to the aircraft and plans to keep it in service until 2036.

After 21 years of service, 85-0073 was retired to The Boneyard at Davis-Monthan Air Force Base, Tucson, Arizona, 24 March 2008.

Rockwell B-1B Lancer, 85-0073, Wings of Freedom, at Ellsworth AFB, South Dakota, 21 January 1987. (U.S. Air Force)
Rockwell B-1B Lancer, 85-0073, Wings of Freedom, at Ellsworth AFB, South Dakota, 21 January 1987. (U.S. Air Force)

© 2019, Bryan R. Swopes