Tag Archives: Bomber

14 September 1962

Major Fitzhugh L. Fulton, Jr., U.S. Air Force, in the cockpit of a Convair B-58A Hustler Mach 2+ strategic bomber. (U.S. Air Force)

14 September 1962: At Edwards Air Force Base, in the high desert of southern California, Major Fitzhugh L. Fulton, Jr., United States Air Force, with Captain William R. Payne, USAF, and civilian flight test engineer C.R. Haines, flew a Convair B-58A-10-CF Hustler, serial number 59-2456, to a record 26,017.93 meters (85,360.66 feet) while carrying a 5,000 kilogram payload. This set a Fédération Aéronautique Internationale (FAI) World Record for Altitude in both the 2,000 kilogram (4,409.25 pounds) ¹ and 5,000 kilogram (11,023.11 pounds) ² classes.

Left to right, Major Fitzhugh L. Fulton, Jr., USAF, Captain William R. Payne, USAF, and civilian flight test engineer C.R. Haines. (FAI)
Left to right, Major Fitzhugh L. Fulton, Jr., USAF, Captain William R. Payne, USAF, and civilian flight test engineer C.R. Haines. (FAI)
Fitzhugh L. Fulton, Jr., 1942.

Fitzhugh Lee Fulton, Jr., was born 6 June 1925 at Blakeley, Georgia. He was the son of Fitzhugh Lee Fulton and Manila T. Fulton. He graduated from Columbus High School, Columbus, Georgia, in 1942. He later studied at Auburn University, Auburn, Alabama, and the University of Oklahoma, Norman, Oklahoma (just south of Oklahoma City). he graduated from Golden Gate University, San Francisco, California.

Fitz Fulton married Miss Erma I. Beck at Tucson, Arizona, 16 December 1945.

He entered the U.S. Army Air Corps in 1943. He flew the Douglas C-54 Skymaster transport during the Berlin Airlift and Douglas B-26 Invaders during the Korean War. Fulton graduated from the Air Force Experimental Test Pilot School in 1952. He served as project test pilot for the Convair B-58 Hustler supersonic bomber. At Edwards AFB, he flew the B-52 “motherships” for the X-15 Program. He flew the North American XB-70A Valkyrie to more than Mach 3. When Fulton retired from the Air Force in 1966, he was a lieutenant colonel assigned as Chief of Bomber and Transport Test Operations.

Fitz Fulton continued as a test pilot for NASA, flying as project pilot for the YF-12A and YF-12C research program. He flew all the early test flights of the NASA/Boeing 747 Shuttle Carrier Aircraft and carried the space shuttle prototype, Enterprise. By the time he had retired from NASA, Fulton had flown more than 16,000 hours in 235 aircraft types.

Fitzhugh Lee Fulton, Jr., died at Thousand Oaks, California, 4 February 2015, at the age of 89 years.

Convair B-58A-10-CF Hustler 59-2456 with a full weapons load. Major Fitzhugh L. Fulton, U.S. Air Force, flew this Mach 2+ strategic bomber to an altitude of 16.2 miles (26 kilometers) over Edwards Air Force Base, California, 14 September 1962. (U.S. Air Force)

The B-58 Hustler was a high-altitude Mach 2 strategic bomber which served with the United States Air Force from 1960 to 1970. It was crewed by a pilot, navigator/bombardier and a defensive systems operator located in individual cockpits. The aircraft is a delta-winged configuration similar to the Convair F-102A Delta Dagger and F-106 Delta Dart supersonic interceptors.

The Hustler is 96 feet, 10 inches (29.515 meters) long, with a wing span of 56 feet, 10 inches (17.323 meters) and an overall height of 31 feet 5 inches (9.576 meters). The wing’s leading edge is swept back at a 60° angle and the fuselage incorporates the “area rule” which resulted in a “wasp waist” or “Coke bottle” shape for a significant reduction in aerodynamic drag. The airplane’s only control surfaces are two “elevons” and a rudder, and there are no flaps.

The B-58A was powered by four General Electric J79-GE-5 axial-flow afterburning turbojet engines, suspended under the wings from pylons. This was a single-shaft engine with a 17-stage compressor and 3-stage turbine, rated at 10,300 pounds of thrust (45.82 kilonewtons), and 15,600 pounds (69.39 kilonewtons) with afterburner. The J79-GE-5 was 16 feet, 10.2 inches (5.136 meters) long and 3 feet, 2.0 inches (0.965 meters) in diameter.

The bomber had a cruise speed of 610 miles per hour (981.7 kilometers per hour) and a maximum speed of 1,325 miles per hour (2,132.4 kilometers per hour). The service ceiling is 64,800 feet (19,751 meters). Unrefueled range is 4,400 miles (7,081 kilometers). Maximum weight is 168,000 pounds (76,203.5 kilograms).

The B-58 weapons load was a combination of a W-39 warhead, and/or Mk.43 or B61 nuclear bombs. The W-39 warhead, the same used with the Redstone IRBM or Snark cruise missile, was carried in a jettisonable centerline pod, which also carried fuel for the aircraft. The smaller bombs were carried on underwing hardpoints. For defense, there was a General Electric M61 Vulcan 20×102 mm six-barreled rotary cannon mounted in the tail, with 1,200 rounds of linked ammunition, controlled by the Defensive Systems Officer.

Convair B-58A-10-CF 59-2456 was assigned to the 43rd Bombardment Wing at Carswell Air Force Base, Texas until 1969 when it was placed in storage at Davis-Monthan Air Force Base, Tucson, Arizona, 9 December 1969. The record-setting strategic bomber was scrapped 1 June 1977.

FAI altitiude record setting Convair B-58A-10-CF 59-2456, showing the bomber's weapons capability. (U.S. Air Force)
FAI altitude record setting Convair B-58A-10-CF 59-2456, showing the bomber’s weapons capability. Major Fitzhugh L. Fulton, U.S. Air Force, flew this Mach 2+ strategic bomber to an altitude of 16.2 miles (26 kilometers) over Edwards Air Force Base, California, 14 September 1962. (U.S. Air Force)

¹ FAI Record File Number 14656

² FAI Record File Number 14652

© 2017, Bryan R. Swopes

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28 August 1957

English Electric Canberra B Mk.2 WK163 climbing under rocket power. (Institution of Mechanical Engineers)
English Electric Canberra B Mk.2 WK163 climbing under rocket power. (Institution of Mechanical Engineers)

28 August 1957: Michael Randrup, Chief Test Pilot of D. Napier and Son, Ltd., and Walter Shirley, Deputy Chief Engineer, fly this Royal Air Force/English Electric Canberra B Mk.2, WK163, to an altitude of 21,430 meters (70,308 feet) over southern England.  This set a new Fédération Aéronautique Internationale (FAI) World Record for altitude.¹

WK163 with rocket engine installed in its bomb bay. (Institution of Mechanical Engineers)
WK163 with rocket engine installed in its bomb bay. (Institution of Mechanical Engineers)

The Canberra was being used to test Napier’s Double Scorpion NSc D1-2 rocket engine, which was used to drive the airplane far beyond its normal service ceiling of 48,000 feet (14,630 meters).

After taking off from Luton, Bedfordshire, at 5:26 p.m., Mike Randrup used the Canberra’s two 6,500-pounds-thrust (28.91 kilonewtons) Rolls-Royce Avon RA.3 Mk. 101 turbojet engines to climb to 44,000 feet (13,411 meters), where he throttled the engines back to cruising r.p.m. and then ignited the Double Scorpion. The Canberra climbed at a very steep angle until reaching the peak altitude.

English Electric Canberra B Mk.2 WK163. (Institution of Mechanical Engineers)
English Electric Canberra B Mk.2 WK163. (Institution of Mechanical Engineers)

At this high altitude, there is an extremely narrow margin between the airplane’s stall speed and it’s critical Mach number—the point at which supersonic shock waves start to form on the wings and fuselage. On an Airspeed Limitations Chart, this area is known as “Coffin Corner.” Aerodynamicists had calculated that Randrup needed to keep the Canberra within a 15-knot range of airspeed.

Though the Canberra’s cockpit was pressurized, both Mike Randrup and Walter Shirley wore pressure suits in case of emergency.

WK163 landed back at Luton at 6:12 p.m.

Flight of Canberra WK163, 27 August 1957. (Flight)

In 1958, the Royal Aero Club of Great Britain awarded the Britannia Trophy to Randrup and Shirley.

The English Electric Canberra B.2 was the first production variant of a twin-engine, turbojet powered light bomber. The bomber was operated by a pilot, navigator and bombardier. It was designed to operate at very high altitudes. The Canberra B.2 was 65 feet, 6 inches (19.964 meters) long with a wingspan of 64 feet, 0 inches (19.507 meters) and height of 15 feet, 7 inches (4.750 meters). The wing used a symmetrical airfoil and had 2° angle of incidence. The inner wing had 2° dihedral, and the outer wing, 4° 21′. The total wing area was 960 square feet (89.2 square meters). The variable-incidence tail plane ad 10° dihedral. The airplane’s maximum takeoff weight was 46,000 pounds ( kilograms).

The Canberra B.2 was powered by two Rolls-Royce Avon RA.3 Mk. 101 engines. The RA.3 was a single-spool axial-flow turbojet with a 12-stage compressor section and single-stage turbine. It was rated at 6,500-pounds-thrust (28.91 kilonewtons).

The B.2 had a maximum speed of 450 knots (518 miles per hour/833 kilometers per hour). It was restricted to a maximum 0.75 Mach from Sea Level to 15,000 feet (4,572 meters), and 0.79 Mach from 15,000 to 25,000 feet (7.620 meters). Above that altitude the speed was not restricted, but pilots were warned that they could expect compressibility effects at 0.82 Mach or higher.

The Canberra was produced in bomber, intruder, photo reconnaissance, electronic countermeasures and trainer variants by English Electric, Handley Page, A.V. Roe, and Short Brothers and Harland. In the United States, a licensed version, the B-57A Canberra, was built by the Glenn L. Martin Company. The various versions were operated by nearly 20 nations. The Canberra was the United Kingdom’s only jet-powered bomber for four years. The last one in RAF service, a Canberra PR.9, made its final flight on 28 July 2008.

WK163 was built under license by A.V. Roe at Woodford, Cheshire, in 1954, and accepted by the Royal Air Force 28 January 1955. Having spent its entire career as a research test bed, WK163 was declared surplus in 1994 and sold at auction to Classic Air Projects Ltd. It was assigned civil registration G-BVWC.

English Electric Canberra B Mk.2 WK163, 1997. (Mike Freer/Wikipedia)

G-BVWC last flew in 2007. As of December 2016, the record-setting Canberra was undergoing a full restoration at Robin Hood Airport, near Doncaster, South Yorkshire.

English Electric Canberra B2 WK163 (G-BVWC). (Tony Hisgett, via Wikipedia)
English Electric Canberra B Mk.2 WK163, civil registration G-BVWC. The record-setting airplane has been painted in the standard Bomber Command scheme with markings of No. 617 Squadron. (Tony Hisgett, via Wikipedia)

Michael Randrup was born in Moscow, Imperial Russia, 20 April 1913. He was one of four children of Søren Revsgaard Randrup and Alexandra Pyatkova Randrup. He held Danish citizenship through his father, who had emigrated to Russia in 1899. Following the Russian revolution, the Randrup family relocated to England.

Michael was educated at The King’s School in Canterbury, Kent. He became interested in aviation in his early teens, and took his first flight as a passenger aboard an Avro 504K biplane. He began flight lessons at Bekesbourne Aerodrome in 1935, and soloed in June 1936. Randrup applied to join the Royal Air Force but was turned down because of his Danish citizenship. He then went to the Automobile Engineering College in Chelsea, West London, to study aeronautical engineering.

Randrup graduated in 1939, and along with a cousin, Ivan Christian Randrup, formed a small air charter company, AllFlights Ltd., at Heston Aerodrome, west of London. They operated a de Havilland DH.85 Leopard Moth, de Havilland DH.90 Dragonfly, and a Heston Type I Phoenix II (G-AEYX). The Phoenix was impressed into service by the R.A.F., 5 March 1940.

World War II bought their fledgling company to a close. (Ivan Randrup briefly flew for B.O.A.C. before going on to the Air Transport Auxiliary. First Officer Randrup died 29 January 1941.)

After Denmark fell to Nazi Germany in April 1940, Michael Randrup was accepted by the R.A.F. He received a commission as a Pilot Officer on probation, Royal Air Force Volunteer Reserve, 4 September 1940. One year later he was promoted to Flying Officer.

On completion of his military flight training, Pilot Officer Randrup was sent to a flying instructors school. For the next two years, he served as a military flight instructor in England and Southern Rhodesia. In 1942, Flying Officer Randrup was transferred from Training Command to Fighter Command and on 6 October, was assigned to No. 234 Squadron, then stationed at RAF Perranporth, flying the Supermarine Spitfire Vc. A number of Danish pilots had been assigned to No. 234. On 1 January 1943, Randrup was seconded to Air Service Training, Ltd., at Hamble, just southeast of Southampton, where he flight-tested new-production, repaired and overhauled Spitfire fighters.

In 1944, Randrup was assigned as a test pilot at the Royal Aircraft Establishment at Farnborough. Among other assignments, he flight-tested a captured Heinkel He 177 A-5/R-6 twin-engine heavy bomber. In 1945, Randrup was appointed Officer Commanding, Engine Research and Development Flight. By the end of the war, he had been promoted to the rank of Squadron Leader.

Following the war, Randrup went to work for D. Napier and Son Ltd. In 1946, he became the company’s Chief Test Pilot. The following year, he became a naturalized subject of the United Kingdom and the British Empire.

From 1966 until 1973, Randrup served as manager for the British Aircraft Corporation in Saudi Arabia. BAC provided aircraft and missiles to the Royal Saudi Air Force.

Michael Randrup was twice married, first to Florence May Dryden, and then to Betty Perry. They would have two children.

Michael Randrup died in February 1984 at the age of 70 years.

Walter Shirley, Napier Chief Development Engineer (left), and Michael Randrup, Chief Test Pilot, D. Napier and Son Ltd. (Photograph courtesy of Neil Corbett, Test & Research Pilots, Flight Test Engineers)

Walter Shirley was educated at the Blackpool Grammar School, a private boarding school in Blackpool, Lancashire, and St. Catherine’s College, University of Cambridge.

Shirley was employed as a scientific officer at RAE Farnborough from 1942 to 1946. It was while there that he first flew as a flight test engineer with Squadron Leader Randrup. Shirley was sent to an R.A.F. flight school for pilot training. In 1946, he was assigned to rocket engine development.

Shirley joined Napier in 1947, working on turbine engines. In 1952, he was appointed Chief Technician. In 1956, Shirley was made the Chief Development Engineer for the Scorpion engine. He later became the company’s Deputy Chief Engineer.

Walter Shirley died in 1993.

The Britannia Trophy of the Royal Aero Club of Great Britain.

¹ FAI Record File Number 9843

© 2018, Bryan R. Swopes

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9 August 1945

Martin-Omaha B-29-35-MO Superfortress 44-27297, Bockscar, at the National Museum of the United States Air Force. (U.S. Air Force)

9 August 1945: Three days after an atomic bomb had been used against the Japanese industrial city of Hiroshima, a second attack was made on Nagasaki. Major Charles W. Sweeney, in command of the Martin-Omaha B-29-35-MO Superfortress 44-27297, named Bockscar, departed Tinian Island in the Marshal Group at 3:47 a.m., and flew to Iwo Jima where it was to rendezvous with two other B-29s, The Great Artiste and The Big Stink, the instrumentation and photographic aircraft for this mission.

Like its sistership, Enola Gay, 44-27297 was a specially modified “Silverplate” B-29. The Silverplate B-29s differed from the standard production bombers in many ways. They were approximately 6,000 pounds (2,722 kilograms) lighter. The bomber carried no armor. Additional fuel tanks were installed in the rear bomb bay. The bomb bay doors were operated by quick-acting pneumatic systems. The bomb release mechanism in the forward bomb bay was replaced by a single-point release as was used in special British Lancaster bombers. A weaponeer’s control station was added to the cockpit to monitor the special bomb systems.

Bockscar had four air-cooled, supercharged, 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division R-3350-41 (Cyclone 18 787C18BA3) two-row 18-cylinder radial engines with direct fuel injection. The R-3350-41 had a compression ratio of 6.85:1 and required 100/130 aviation gasoline. It was rated at 2,000 horsepower at 2,400 r.p.m. at Sea Level, and 2,200 horsepower at 2,800 r.p.m, for take-off. The engines drove four-bladed Curtiss Electric reversible-pitch propellers with a diameter of 16 feet, 8 inches (5.080 meters), through a 0.35:1 gear reduction. The R-3350-41 was 6 feet, 2.26 inches (1.937 meters) long, 4 feet, 7.78 inches (1.417 meters) in diameter and weighed 2,725 pounds (1,236 kilograms).

With the exception of the tail gunner’s position, all defensive armament—four powered remotely operated gun turrets with ten .50-caliber machine guns—were deleted. Their remote sighting positions were also removed. Enola Gay carried 1,000 rounds of ammunition for each of the two remaining Browning AN-M2 .50-caliber machine guns in the tail.

With these changes, the Silverplate B-29s could fly higher and faster than a standard B-29, and the fuel-injected R-3350-41 engines were more reliable. Bockscar had a cruising speed of 220 miles per hour (354 kilometers per hour) and a maximum speed of 365 miles per hour (587 kilometers per hour). Its service ceiling was 31,850 feet (9,708 meters) and its combat radius was 2,900 miles (4,667 kilometers).

Martin-Omaha B-29-35-MO Superfortress 44-27297, Bockscar, in flight. Note "Triangle N" tail code. (U.S. Air Force)
Martin-Omaha B-29-35-MO Superfortress 44-27297, Bockscar, in flight. Note “Triangle N” tail code. (U.S. Air Force)

44-27297, Victor 7, was assigned to aircraft commander Captain Frederick C. Bock and his crew. Major Sweeney and his crew ordinarily flew The Great Artiste. Sweeney’s B-29 had been the the instrumentation aircraft for the Hiroshima mission and there was not time to remove that equipment and re-install it aboard Bock’s bomber, so the crews switched airplanes. For operational security, Bockscar‘s normal identification was changed from the number 7 on the fuselage to 77. The 509th’s tail code of a circle surrounding a forward-pointing arrow was changed to another unit’s “Triangle N” identification.

All of these last minute changes resulted in confusion in contemporary reports as to which B-29 had actually dropped Fat Man on Nagasaki.

Boeing B-29 crew photo taken Aug. 11, 1945, two days after the Nagasaki mission. Note there is no nose art on the aircraft. (U.S. Air Force photo)
Major Charles W. Sweeney’s B-29 crew. (U.S. Air Force)

In Bockscar‘s forward bomb bay was a 10,213 pound (4,632 kilograms) bomb called Fat Man. This was a completely different and much more complex weapon than the Little Boy (Mark I) atomic bomb dropped by Colonel Paul Tibbet’s Enola Gay on 6 August. Designated Mark III, the egg-shaped weapon contained a 6.2 kilogram (14 pound) sphere of Plutonium Pu 239, surrounded by a high-explosive charge. The explosives were formed in “lenses” that would direct the force inward in a very precise manner. The purpose was to compress—or implode— the Plutonium to a much greater density, resulting in a “critical mass.”

The Mark III "Fat Man" bomb loaded on its carrier, 8 August 1945.
The Mark III “Fat Man” bomb being loaded onto its carrier, 8 August 1945.

In the conduct of this mission, Major Sweeney made a number of serious errors that nearly caused the mission to fail, and might very well have led to the loss of the bomber and its crew.

Prior to takeoff, the B-29’s crew chief informed Sweeney that a fuel transfer pump was inoperative which made it impossible to transfer 625 gallons (2,366 liters) of fuel from one fuel tank. This meant that nearly 9% of the total fuel load of 7,250 gallons (27,444 liters) was unusable. Chuck Sweeney decided to go anyway.

Next, though under direct orders from the 509th Composite Group commander, Colonel Paul Tibbets, to wait at the rendezvous no more than 15 minutes, when The Big Stink failed to arrive on schedule, Sweeney elected to stay 30 minutes beyond that.

Meanwhile, the two weather reconnaissance B-29s, Enola Gay and Laggin’ Dragon, were over Kokura, the primary target, and the secondary, Nagasaki. Weather over both cities were within the mission parameters.

XX Bomber Command Target Chart for Nagasaki Area. (National Archives)

During the 45 minutes that Sweeney waited at the rendezvous, weather over Kokura had deteriorated. By the time Bockscar arrived overhead, clouds covered the city. The bomber made three attempts to bomb the city over a 50-minute period, but the bombardier was not able to see the target.

Now an hour and twenty minutes behind schedule, Sweeney diverted to the secondary target, Nagasaki. Because of the delays and the unusable fuel as a result of the failed fuel pump, Sweeney reduced engine power to try to conserve fuel during the twenty minute flight to the alternate target. But weather there had also deteriorated.

Sweeney decided that they should bomb through the clouds using radar, but at the last minute, the bombardier was able to see the aim point. The Fat Man was dropped from 30,000 feet (9,144 meters) at 11:01 a.m. After falling for 43 seconds, the atomic bomb detonated at an altitude of 1,950 feet (594.4 meters). It missed the intended target point by nearly 1.5 miles (2.4 kilometers) and exploded over the Urakami Valley, halfway between the Mitsubishi Steel and Arms Works and the Mitsubishi-Urakami Ordnance Works.

Nagasaki, 9 August 1945, photographed by Joe Kosstatscher, U.S. Navy.
Nagasaki, 9 August 1945, photographed by Joe Kosstatscher, U.S. Navy.

The estimated force of the explosion was 21 kilotons—equivalent to the explosive force of 21,000 tons of TNT (19,050 metric tons)—nearly 20% greater than the Hiroshima bomb. The surrounding hills contained the explosion, protecting a large part of the city. Still, approximately 60% of Nagasaki was destroyed and 70,000 people were killed. By December 1945, at least 80,000 of the city’s 250,000 residents had died.

Atomic cloud rising over nagasaki, japan, 9 August 1945, photographed from Koyagi-jima. (Hiromichi Matsuda)
Pyrocumulus cloud rising over Nagasaki, Japan, approximately 20 minutes after detonation, 9 August 1945, photographed from Koyagi-jima, a small island southwest of Nagasaki. (Hiromichi Matsuda)

Now critically low on fuel and unable to reach the emergency B-29 recovery field on Iwo Jima, Sweeney headed for the airfields of Okinawa. When Bockscar touched down on the runway, one engine quit due to fuel starvation. As they turned off the runway, a second engine ran out of fuel. Charles Sweeney had cut it very, very close.

B-29 44-27297 on Tinian Island, August 1945. The nose art was applied to the airplane after the August 9, 1945 bombing mission. (U.S. Air Force)
Martin-Omaha B-29-35-MO 44-27297 on Tinian Island, August 1945. The nose art was applied to the airplane after the August 9, 1945 bombing mission. (U.S. Air Force)

Five days after the bombing of Nagasaki, the Emperor of Japan—recognizing that his country now faced total destruction—agreed to surrender. World War II was over.

In 1946, Bockscar was placed in storage at Davis-Monthan Army Air Field, Tucson, Arizona. On 26 September 1961, the B-29 was flown to the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Dayton, Ohio, where it remains in the museum’s collection of historic aircraft.

DAYTON, Ohio — Boeing B-29 Superfortress “Bockscar” at the National Museum of the United States Air Force. (U.S. Air Force photo)

© 2018, Bryan R. Swopes

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6 August 1945

Silverplate Martin-Omaha B-29-45-MO Superfortress 44-86292, “Dimples 82,” at Tinian, Marshall Islands, August 1945. Note the “Circle Arrowhead” tail code. (U.S. Air Force)

6 August 1945: At 0245 hours, a four-engine, long range heavy bomber of the 509th Composite Group, United States Army Air Forces, took off from North Field on the island of Tinian in the Northern Mariana Islands, on the most secret combat mission of World War II.

Colonel Paul Warfield Tibbets, Jr., United States Army Air Forces, Commanding Officer, 509th Composite group, and aircraft commander of the B-29 Superfortress, Enola Gay. (U.S. Air Force)
Colonel Paul Warfield Tibbets, Jr., United States Army Air Corps, Commanding Officer, 509th Composite Group, and aircraft commander of the B-29 Superfortress, Enola Gay. (U.S. Air Force)

The Martin-Omaha B-29-45-MO Superfortress, 44-86292, under the command of Colonel Paul W. Tibbets, Jr., was carrying Bomb Unit L-11, the first nuclear weapon to be used during war. This was a 9,700-pound (4,400 kilogram) “gun type” fission bomb, the Mark I, code-named Little Boy. It contained 64 kilograms (141.1 pounds) of highly-enriched uranium. The bomb was 120 inches (3.048 meters) long with a diameter of  28 inches (0.711 meter). Although it was a very inefficient weapon, it was considered to be such reliable design that it had not been tested.

Code named "Little Boy," the Mark I bomb unit L-11, prior to loading aboard Enola Gay, 5 August 1945. (U.S. Air Force)
Code named “Little Boy,” the Mark I bomb unit L-11, prior to loading aboard Enola Gay, 5 August 1945. (U.S. Air Force)

On the morning before the mission, Colonel Tibbets had his mother’s name painted on the nose of the airplane: Enola Gay. He had personally selected this bomber, serial number 44-86292, while it was still on the assembly line at the Glenn L. Martin Company plant at Bellevue, Nebraska, 9 May 1945. The B-29 was accepted by the Army Air Corps on 15 May and flown to the 509th’s base at Wendover, Utah, by Captain Robert A. Lewis, a B-29 aircraft commander who would act as Tibbets’ co-pilot on the atomic bombing mission.

The B-29 Superfortress was designed by the Boeing Airplane Company as its Model 345. Produced in three major version, the B-29, B-29A and B-29B, it was built by Boeing at Wichita, Kansas and Redmond, Washington; by the Bell Aircraft Corporation at Marietta, Georgia; and the Glenn L. Martin Company at Fort Crook (now Offutt Air Force Base, Omaha, Nebraska. A total of 3,943 Superfortresses were built.

The B-29 was the most technologically advanced airplane built up to that time, and required an immense effort by American industry to produce.

The B-29 Superfortress was 99 feet, 0 inches (30.175 meters) long with a wingspan of 141 feet, 3 inches (43.053 meters) and an overall height of 27 feet, 9 inches (8.458 meters). The standard B-29 had an empty weight of 74,500 pounds (33,793 kilograms) and gross weight of 120,000 pounds (54.431 kilograms).

Enola Gay at Tinian, with crew members.
Enola Gay at Tinian, with crew members.

The Silverplate B-29s differed from the standard production bombers in many ways. They were approximately 6,000 pounds (2,722 kilograms) lighter. The bomber carried no armor. Additional fuel tanks were installed in the rear bomb bay. The bomb bay doors were operated by quick-acting pneumatic systems. The bomb release mechanism in the forward bomb bay was replaced by a single-point release as was used in special British Lancaster bombers. A weaponeer’s control station was added to the cockpit to monitor the special bomb systems.

Colonel Paul W. Tibbets, Jr., waves from the cockpit of the Silverplate Martin-Omaha B-29-45-MO Superfortress Enola Gay, 44-86292, just before starting engines at 02:27 a.m., 6 August 1945. (Sergeant Armen Shamlian, United States Army Air Forces. National Archives and Records Administration)

Enola Gay had four air-cooled, supercharged, 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division R-3350-41 (Cyclone 18 787C18BA3) two-row 18-cylinder radial engines with direct fuel injection. The R-3350-41 had a compression ratio of 6.85:1 and required 100/130 aviation gasoline. It was rated at 2,000 horsepower at 2,400 r.p.m. at Sea Level, and 2,200 horsepower at 2,800 r.p.m, for take-off. The engines drove four-bladed Curtiss Electric reversible-pitch propellers with a diameter of 16 feet, 8 inches (5.080 meters), through a 0.35:1 gear reduction. The R-3350-41 was 6 feet, 2.26 inches (1.937 meters) long, 4 feet, 7.78 inches (1.417 meters) in diameter and weighed 2,725 pounds (1,236 kilograms).

With the exception of the tail gunner’s position, all defensive armament—four powered remotely operated gun turrets with ten .50-caliber machine guns—were deleted. Their remote sighting positions were also removed. Enola Gay carried 1,000 rounds of ammunition for each of the two remaining Browning AN-M2 .50-caliber machine guns in the tail.

With these changes, the Silverplate B-29s could fly higher and faster than a standard B-29, and the new engines were more reliable. Enola Gay had a cruising speed of 220 miles per hour (354 kilometers per hour) and a maximum speed of 365 miles per hour (587 kilometers per hour). Its service ceiling was 31,850 feet (9,708 meters) and its combat radius was 2,900 miles (4,667 kilometers).

XXI Bomber Command Target Chart for Hiroshima Area. (U.S. Strategic Bombing Survey)
XXI Bomber Command Target Chart for Hiroshima. (U.S. Strategic Bombing Survey)

At 09:15:17 a.m., (mission time, 8:15 a.m., local), Enola Gay was at 31,000 feet (9,450 meters) over the Japanese city of Hiroshima on the island of Honshu, an industrial center with a population of about 340,000 people. The bombardier initiated the automatic release sequence and the the atomic bomb was dropped. It fell for 44.4 seconds and detonated at an altitude of 1,968 feet (600 meters), about 800 feet (244 meters) from the aiming point, the Aioi Bridge over the Ota River.

The mushroom cloud rises over Hiroshima, Japan, 2–3 minutes after detonation. Photographed 6,500 meters from hypocenter (Seizo Yamada)
The mushroom cloud rises over Hiroshima, Japan, 2–3 minutes after detonation. Photographed 6,500 meters (4 miles) from hypocenter (Seizo Yamada)
A mushroom cloud rises over the devastated city Hiroshima, Japan, 2–3 minutes after detonation, 6 August 1945, photographed by Technical Sergeant George R. Caron, U.S. Army Air Corps, tail gunner of the B-29 Enola Gay, using a Fairchild Camera and Instrument Company K-20 aerial camera with a 6-3/8" f/4.5, 4" × 5" film negative. (National Archives RG 77-AEC)
A mushroom cloud rises 20,000 feet (6,100 meters) over the devastated city of Hiroshima, Japan, 2–3 minutes after detonation, 6 August 1945, photographed from Yoshiura, looking southward, by Technical Sergeant George R. Caron, U.S. Army Air Corps, tail gunner of the B-29 Enola Gay, using a Fairchild Camera and Instrument Company K-20 aerial camera with a 6-3/8″ f/4.5, 4″ × 5″ film negative. (U.S. Air Force)
Pyrocumulus cloud seen from ground level.
Two-tier cloud 2–5 minutes after detonation, seen from Kaitaichi, 6 miles east of Hiroshima. Photographer unknown. (The Atlantic)
Pyrocumulus cloud rising over Hiroshima. Photographer unknown. (Atomic Heritage Foundation)
A pyrocumulus cloud from the firestorm spreads laterally as it reaches the upper atmosphere. (U.S. Air Force)
A pyrocumulus cloud from the firestorm spreads laterally as it reaches the upper atmosphere. (U.S. Air Force)
Hiroshima photoggraphed by a reconnaissance airplane several hours after the explosion. (U.S. Air Force)
Hiroshima photographed by a reconnaissance airplane several hours after the explosion. (U.S. Air Force)

Ground Zero, the point on the surface directly below the explosion, was the Shima Hospital. The overpressure is estimated to have been 4.5–6.7 tons per square meter. The two-story brick building was completely obliterated. Of the patients, technicians, nurses and doctors inside, nothing remained.

The entrance to Shima Hospital is all the remained following the detonation of the atomic bomb.

The resulting explosion was approximately equivalent in explosive force to the detonation of 16,000 tons (14,515 metric tons) of TNT (16 “kilotons”). An estimated 70,000 people were killed immediately, and another 70,000 were wounded. As many as 160,000 people may have died as a result of the atomic bombing by the end of 1945. More would follow over the next few years.

The shadow of one of the victims of the atomic bomb is etched onto the steps in front of a destroyed building.
The shadow of one of the victims of the atomic bomb is etched onto the steps in front of a destroyed building.

An area of the city with a radius of 1 mile (1.6 kilometers) from the point of detonation (“hypocenter”) was totally destroyed, and combined with the fires that followed, 4.7 square miles (12.17 kilometers²) of the city were destroyed. 69% of all buildings in Hiroshima were completely destroyed and another 6% damaged.

Hisroshima photographed in March 1946. (National Archives)
Hisroshima photographed in March 1946. (National Archives)

As soon as the bomb was released, Colonel Tibbets turned his B-29 away to avoid the blast. It was just over 11 miles (17.7 kilometers) from the detonation point when the shock waves hit, but no damage resulted. The bomber was then flown back to Tinian, landing after an elapsed time of 12 hours, 13 minutes.

Col. Tibbets’ B-29, Enola Gay, 44-86292, landing at Tinian Island, 6 August 1945. Note: “Circle R” identification on tail. (U.S. Air Force)
Martin-Omaha Silverplate B-29 Superfortress 44 86292, Enola Gay, taxis to its hardstand after returning to Tinian, 6 August 1945. (U.S. Air Force)
Martin-Omaha Silverplate B-29 Superfortress 44 86292, Enola Gay, taxis to its hardstand after returning to Tinian, 6 August 1945. (U.S. Air Force)

Enola Gay was placed in storage at Davis-Monthan Army Air Field, Tucson, Arizona, 26 July 1946, and was transferred to the Smithsonian Institution just over one month later, 30 August 1946. For decades it sat in storage at different locations around the country, but finally a total restoration was performed. Today, the B-29 is on display at the Steven F. Udvar-Hazy Center, National Air and Space Museum.

Martin-Omaha B-29-45-MO Superfortress 44-86292, Enola Gay, at teh Steven F. Udvar-Hazy Center, Smithsonian Institution National Air and Space Museum.
Martin-Omaha B-29-45-MO Superfortress 44-86292, Enola Gay, at the Steven F. Udvar-Hazy Center, Smithsonian Institution National Air and Space Museum. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution )

© 2017, Bryan R. Swopes

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1 August 1939

The flight crew of the FAI World Altitude Record-setting Boeing Y1B-17A. Left to right: Captain Pearl H. Robey, Captain Clarence S. Irvine and R. Swofford. (FAI)

1 August 1939: Captains Clarence S. Irvine and Pearl H. Robey, United States Army Air Corps, used the Boeing Y1B-17A Flying Fortress (Model 299F), serial number 37-369, to set a Fédération Aéronautique Internationale (FAI) World Record for Altitude with a 5,000 Kilogram Payload. The bomber climbed to 34,026 feet with a payload of 11,023 pounds.¹ ²

On the same day, Irvine and Robey flew the Y1B-17 from Dayton, Ohio to St. Jacob, Illinois, setting an FAI World Record for Speed Over 1,000 Kilometers with a 5,000 Kilogram Payload, averaging 417.46 kilometers per hour (259.40 miles per hour).³

The flight crew of the FAI World Speed Record-setting Boeing Y1B-17A. Left to Right: Capatain C.J. Crane, P.G. Miller, Captain Clarence S. Irvine and Captain pearl H. Robey. (FAI)
The flight crew of the FAI World Speed Record-setting Boeing Y1B-17A. Left to Right: Captain Carl J. Crane, P.G. Miller, Captain Clarence S. Irvine and Captain Pearl H. Robey. (FAI)

The single Y1B-17A (Boeing Model 299F) was originally ordered as a static test article, but when that was determined to be unnecessary, it was used as an engine test aircraft. It was equipped with four 1,823.129-cubic-inch-displacement (29.875 liter) air-cooled, supercharged, Wright R-1820-51 (Cyclone G59) single-row nine-cylinder radial engines. Moss/General Electric turbo-superchargers were installed, initially on top of the wings, but were moved to the bottom of the engine nacelles.

Boeing Y1B-17A 37-369. (FAI)

The supercharged Wright R-1820-39 (Cyclone R-1820-G5) engines of the YB-17s were rated at 805 horsepower at 2,100 r.p.m., at Sea Level, 775 horsepower at 14,000 feet (4,267 meters), and 930 horsepower at 2,200 r.p.m., for take off. By contrast, the YB-17A’s R-1820-51 engines were rated at 800 horsepower at 2,100 r.p.m. at Sea Level, and 1,000 horsepower at 2,200 r.p.m. for take off. But the turbochargers allowed the engines to maintain their Sea Level power rating all the way to 25,000 feet (7,620 meters). Both the -39 and -51 engine had a 16:11 propeller gear reduction ratio. The R-1820-51 was 3 feet, 9.06 inches (1.145 meters) long, 4 feet, 6.12 inches (1.375 meters) in diameter, and weighed 1,200.50 pounds (544.54 kilograms). 259 were produced by Wright between September 1937 and February 1940.

Boeing Y1B-17A 37-369. (U.S. Air Force)

The turbo-superchargers installed on the YB-17A greatly improved the performance of the bomber, giving it a 55 mile per hour (89 kilometer per hour) increase in speed over the supercharged YB-17s, and increasing the bomber’s service ceiling by 7,000 feet (2,132 meters). The turbo-superchargers worked so well that they were standard on all following B-17 production models.

Boeing Y1B-17A 37-369. (U.S. Air Force photo)

The Boeing Y1B-17A was 68 feet, 9 inches (20.955 meters) long with a wingspan of 103 feet, 9–3/8 inches (31.633 meters) and height of 14 feet, 11–5/16 inches (4.363 meters). Its empty weight was 26,520 pounds (12,029 kilograms). The maximum gross weight was 45,650 pounds (20,707 kilograms)

The Model 299F had a cruise speed of 230 miles per hour (370 kilometers per hour), a maximum speed of 271 miles per hour (436 kilometers per hour) at Sea Level and 295 miles per hour (475 kilometers per hour) at 25,000 feet (7,620 meters). The service ceiling was 38,000 feet (11,582 meters). The maximum range was 3,600 miles (5,794 kilometers). Carrying a 4,000 pound (1,814 kilogram) load of bombs, the range was 2,400 miles (3,862 kilometers).

The Y1B-17A could carry eight 600 pound (272 kilogram) bombs in an internal bomb bay. Defensive armament consisted of five .30-caliber machine guns.

Following the engine tests, 37-369 was re-designated B-17A.

The Boeing Y1B-17A in flight near Mt. Rainier on 28 February 1938. (U.S. Air Force)

¹ FAI Record File Number 8318

² This record-setting flight was dramatized in the motion picture “Test Pilot,” (1938, Metro-Goldwyn-Mayer) with Clark Gable, Spencer Tracy and Myrna Loy. This movie is now 80 years old and has a melodramatic plot, but is well worth seeing for aviation history enthusiasts.

³ FAI Record File Number 10443

© 2018, Bryan R. Swopes

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