Tag Archives: Long Range Heavy Bomber

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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8 July 1941

Fortress Mark I, AN521 ‘WP-K’, of No. 90 Squadron RAF based at West Raynham, Norfolk, preparing for take off at Hatfield, Hertfordshire, during an inspection of newly-arrived American aircraft by the Chief of the Air Staff and the US Air Attache. (Photograph by Flight Lieutenant Bertrand John Henry Daventry, Royal Air Force/CH 2873, Imperial War Museum)
Boeing Fortress Mark I AN521, ‘WP-K’, (U.S.A.A.F. serial number 40-2052) of No. 90 Squadron R.A.F., based at West Raynham, Norfolk, preparing for take off at Hatfield, Hertfordshire, during an inspection of newly-arrived American aircraft by the Chief of the Air Staff and the U.S. Air Attache. Photograph by Flight Lieutenant Bertrand John Henry Daventry, Royal Air Force. © IWM (CH 2873)

00DD3437_5056_A318_A85F9DA3980B669B8 July 1941: Three Royal Air Force Boeing Fortress Mk.I heavy bombers departed from their base at RAF Watton to attack Wilhelmshaven, Germany. This was a daylight bombing mission, with the airplanes flying at 30,000 feet (9,144 meters). One bomber diverted to a secondary target because of engine trouble, while the remaining two Fortresses continued to the primary target.

At the very high altitudes flown, the defensive heavy machine guns that gave the airplane its name froze due to the low temperatures and could not be fired. (In standard atmospheric conditions, the temperature at 30,000 feet would be -45 °C., or -49 °F.)

"Vertical aerial reconnaissance of Wilhelmshaven." © IWM (HU 91201)
“Vertical aerial reconnaissance of Wilhelmshaven.” © IWM (HU 91201)

All three aircraft returned safely to their base. The mission was completely ineffective, however.

This was the very first use of the Boeing B-17 Flying Fortress in combat.

Fortress B.I WP-F
Fortress B.I AN530, WP-F (U.S.A.A.F. B-17C 40-2066) (Royal Air Force)

The Boeing Model 299H, designated B-17C, was the second production variant ordered by the U.S. Army Air Corps. 38 were built by Boeing for the U.S. Army Air Corps, but 20 were transferred to Great Britain’s Royal Air Force, designated Fortress Mk.I. (Boeing Model 299T.) They were initially assigned to No. 90 Squadron, Bomber Command. (A 1941 book, War Wings: Fighting Airplanes of the American and British Air Forces, by David C. Cooke, Robert M. McBride & Company, New York, refers to the B-17C in British service as the “Seattle,” which is in keeping with the R.A.F.’s system of naming bombers after cities.)

Of the 20 Fortress Mk.I bombers, 8 were lost in combat or in accidents.

Boeing Fortress Mk.I AN529 at Heathfield, Scotland, after arrival from United States, May 1941. © Imperial War Museum E(MOS) 276

The Boeing B-17C/Fortress Mk.I was 67 feet, 10-9/16 inches (20.690 meters long with a wingspan of 103 feet, 9 inches (31.633 meters) and the overall height was 15 feet, 4½ inches (4.686 meters). The B-17C had an empty weight of 30,900 pounds (14,016 kilograms). The maximum design gross weight was 47,500 pounds (21,546 kilograms).

The B-17C was powered by four air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.876 liters) Wright Cyclone G666A (R-1820-65)¹ nine-cylinder radial engines with a compression ratio of 6.70:1. The engines were equipped with remote General Electric turbochargers capable of 24,000 r.p.m. The R-1820-65 was rated at 1,000 horsepower at 2,300 r.p.m. at Sea Level, and 1,200 horsepower at 2,500 r.p.m. for takeoff. The engine could produce 1,380 horsepower at War Emergency Power. 100-octane aviation gasoline was required. The Cyclones turned three-bladed, constant-speed, Hamilton-Standard Hydromatic propellers with a diameter of 11 feet, 7 inches (3.835 meters) though a 0.5625:1 gear reduction. The R-1820-65 engine is 3 feet, 11.59 inches (1.209 meters) long and 4 feet, 7.12 inches (1.400 meters) in diameter. It weighs 1,315 pounds (596 kilograms).

Crew members of a No. 90 "RAF Fortress crew at RAF Polebrook July 19, 1941." (IWM CH 3090)
“RAF Fortress crew at RAF Polebrook July 19, 1941.” © IWM (CH 3090)

The B-17C had a maximum speed of 323 miles per hour (520 kilometers per hour) at 25,000 feet (7,620 meters). Its service ceiling was 37,000 feet (11,278 meters) and the maximum range was 3,400 miles (5,472 kilometers).

The Fortress Mk.I could carry 4,800 pounds (2,177 kilograms) of bombs in an internal bomb bay. Defensive armament consisted of one Browning AN-M2 .30-caliber air-cooled machine gun at the nose and four Browning AN-M2 .50-caliber heavy machine guns in dorsal, ventral and waist positions.

Fortress I AN528 (Getty Images/Three Lions)
Royal Air Force Fortress Mk.I AN528 (B-17C 40-2064) prior to being camouflaged. (Getty Images/Three Lions)

© 2018, Bryan R. Swopes

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16–17 May 1943

Wing Commander Guy Penrose Gibson, VC, DSO and Bar, DFC and Bar. (Imperial War Museum)
Wing Commander Guy Penrose Gibson, V.C., D.S.O. and Bar, D.F.C. and Bar. © IWM (CH 11047)

16–17 May 1943: Nineteen modified Avro Lancaster B.III Special long-range heavy bombers of No. 617 Squadron, Royal Air Force, carried out Operation Chastise, a low-level night attack against four hydroelectric dams in the Ruhr Valley.

The purpose of the attack was to disrupt German steel production. It was estimated that 8 tons of water were required to produce 1 ton of steel. Breaching the dams would reduce the available water and hydroelectric power, disrupt transportation of materials on the rivers, and flood iron ore and coal mines and power plants. If the dams were destroyed, it was believed that the effects would be the same as attacks against 26 categories of industrial targets further down the Ruhr Valley.

Led by 24-year-old Wing Commander Guy Penrose Gibson, D.S.O. and Bar, D.F.C. and Bar, a veteran of 172 combat missions, the aircrews of No. 617 Squadron dropped a spinning cylindrical bomb, code-named “Upkeep”, from a height of just 60 feet (18.3 meters) over the reservoirs behind the dams, while flying at precisely 240 miles per hour (386.2 kilometers per hour).

The 9,250-pound (4,195.8 kilogram) Vickers Type 464 bomb was designed to skip along the surface and to strike the dam, and then sink to the bottom. There, a pressure detonator exploded the 6,600 pound (2,994 kilogram) Torpex charge directly against the wall with the water pressure directing the energy through the wall.

Guy Gibson's Avro Lancaster B.III Special, ED932/G, AJ-G, "bombed up" with an Upkeep bomb. © IWM (HU 69915)
Guy Gibson’s Avro Lancaster B.III Special, ED932/G, AJ-G, “bombed up” with a Vickers Type 464 bomb. © IWM (HU 69915)

Nineteen Lancasters took off from RAF Scampton beginning at 9:28 p.m. on the 16th, and flew across the North Sea at only 100 feet (30.5 meters) to avoid being detected by enemy radar. The bombers succeeded in destroying the Möhne and Eder dams and damaging the Sorpe. A fourth dam was attacked but not damaged. The last surviving bomber returned to base at 6:15 a.m. on the 17th.

Of the nineteen Lancasters launched, two were damaged and turned back before reaching the targets. Six were shot down and two more collided with power lines during the low-level night flight. Of 133 airmen participating in the attack, 53 were killed.

GIBSON, Guy, with PO Frederick M. Spafford, FL Robert E.G. Hutchinson, PO Andrew Deering and FO Torger H. Taerum
Wing Commander Guy Penrose Gibson, V.C., D.S.O. and Bar, D.F.C. and Bar, Commander No. 617 Squadron, with the crew of “G George”: Pilot Officer Frederick Mchael Spafford, D.F.C., bomb aimer; Flight Lieutenant Robert Edward George Hutchinson, D.F.C. and Bar, wireless operator; Pilot Officer Andrew Deering, D.F.C., gunner; Flying Officer Torger Harlo Taerum, D.F.C., navigator. Flight engineer Sergeant John Pulford and tail gunner Flight Lieutenant Richard A.D. Trevor-Roper are not present.  © IWM (TR 1127) 

Guy Gibson was awarded the Victoria Cross by King George VI. An additional 33 survivors were also decorated. 617 Squadron became known as “The Dambusters.” A book, The Dam Busters, was written about the raid by Paul Brickhill, who also wrote The Great Escape. A 1955 movie starred Richard Todd, O.B.E., as Wing Commander Gibson. There have been reports that a new movie is planned.

An Avro Lancaster B.III Special drops an "Upkeep" bomb during tests, April 1943. (Imperial War Museum)
An Avro Lancaster B.III Special drops an “Upkeep” bomb during tests at Reculver, April 1943. Imperial War Museum, still from film, IWM (FLM 2340)
After being dropped from an Avro Lancaster, the “special mine” bounces across the water. (Imperial War Museum)
Post-strike reconnaissance photograph shows the breach of the Mohne Dam in the Ruhr Valley, 16 May 1943. (Imperial War Museum)
Post-strike reconnaissance photograph shows the breach of the Möhne Dam in the Ruhr Valley, 17 May 1943. The gap is 250 feet (76 meters) wide and 292 feet (22 meters) deep. © IWM (CH 9687)

The Avro Lancaster B.III Special was a four-engine long range heavy bomber modified to carry the Type 464 bomb. It was operated by a crew of seven: Pilot, flight engineer, navigator, radio operator, bomb aimer, nose gunner and tail gunner. The “Lanc” was 69 feet, 6 inches (21.184 meters) long with a wingspan of 102 feet (31.090 meters) and overall height of 20 feet (6.096 meters). The modified bomber had an empty weight of 35,240 pounds (15,984.6 kilograms and a maximum takeoff weight (MTOW) of 60,000 pounds (27,215.5 kilograms).

The Lancaster B.III Special was powered by the Packard Motor Car Company’s license-built version of the Rolls-Royce Merlin 24, the Packard V-1650-1 Merlin 224. These were liquid-cooled, supercharged, 1,648.96-cubic-inch-displacement (27.022-liter) single overhead cam (SOHC) 60° V-12 engines with four valves per cylinder and a compression ratio of 6.0:1. The Merlin 224 used a two-speed, single-stage supercharger. 100/130-octane aviation gasoline was required. The engine had a Normal Power rating of 1,080 horsepower at 2,650 r.p.m. and 9,500 feet (2,896 meters); Military Power, 1,240 horsepower at 3,000 r.p.m. at 11,000 feet (3,353 meters); and 1,300 horsepower at 3,000 horsepower with 54.3 inches of manifold pressure (1.84 Bar) for Takeoff. The Merlins drove three-bladed de Havilland Hydromatic quick-feathering, constant-speed propellers which had a diameter of 13 feet (3.962 meters). The propeller gear reduction ratio was 0.477:1. The V-1650-1 was 6 feet, 7.7 inches (2.024 meters) long, 2 feet, 6.0 inches (0.762 meters) wide and 3 feet, 6.6 inches (1.082 meters) high. It weighed 1,512 pounds (685.8 kilograms).

These engines gave the Lancaster a cruising speed of 200 miles per hour (321.9 kilometers per hour) and maximum speed of 272 miles per hour (437.7 kilometers per hour). The service ceiling was 24,700 feet (7,528.6 meters) and maximum range was 2,530 miles (4,071.6 kilometers).

Defensive armament for a standard Lancaster consisted of eight air-cooled Browning .303-caliber Mark II machine guns in three power turrets, nose, dorsal and tail. The Lancasters assigned to Operation Chastise had the dorsal turret deleted to reduce weight and aerodynamic drag. The gunner normally operating that turret was moved to the front turret, relieving the bomb aimer to deal with the operation of the specialized mission equipment.

7,377 Avro Lancasters were built. Only two remain in airworthy condition.

The first two modified Avro Lancaster B.III Specials assigned to No. 617 Squadron, RAF Scampton, April 1943. (Royal Air force)
The first two modified Avro Lancaster B.III Specials assigned to No. 617 Squadron, RAF Scampton, April 1943. In the foreground is ED825/G, AJ T. (Royal Air Force)
One of the two flyable Lancasters remaining, “City of London,” the Battle of Britain Memorial Flight Vickers-Armstrongs Ltd.-built Lancaster B.I, PA474. The airplane is marked as “Mickey the Moocher,” EE176, QR M. (Crown Copyright)
Victory Aircraft Ltd.-built Avro Lancaster B Mk.X FM213, marked as KB726, VR A.

Highly Recommended: The Dam Busters, by Paul Brickhill. Evans Brothers, London, 1951

© 2018, Bryan R. Swopes

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15 May 1942

B-24E-1-FO Liberator 42-6976, the first B-24 heavy bomber to come off the assembly line at Willow Run, 15 May 1942. (The Henry Ford THF25680 Ford Motor Co. Willow Run Bomber Plant)
B-24E-1-FO Liberator 42-6976, the first B-24 heavy bomber to come off the assembly line at Willow Run, 15 May 1942. (The Henry Ford THF25680 Ford Motor Co. Willow Run Bomber Plant)

15 May 1942: The first Ford-built B-24 Liberator long range heavy bomber came off the assembly line at the Willow Run Airplane Plant, just 160 days after the United States entered World War II. 6,971 B-24s more would follow, along with assembly kits for another 1,893, before production came to an end, 28 June 1945.

The first Ford-built B-24 Liberator in final assembly at the Willow Run Airplane Plant, 12 May 1942. (Ford)
The first Ford-built B-24 Liberator in final assembly at the Willow Run Airplane Plant, 12 May 1942. (Ford)
B-24E-1-FO Liberator 42-6976, the first B-24 heavy bomber to come off the assembly line at Willow Run, 15 May 1942. (The Henry Ford THF25680 Ford Motor Co. Willow Run Bomber Plant)
B-24E-1-FO Liberator 42-6976, the first B-24 heavy bomber to come off the assembly line at Willow Run, 15 May 1942. (The Henry Ford THF25680 Ford Motor Co. Willow Run Bomber Plant)
Willow Run
The Ford Motor Company Willow Run Airplane Plant
A Willow Run-built B-24E Liberator long range heavy bomber, 1942. (Ford Motor Company)

© 2018, Bryan R. Swopes

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30 April 1959

Convair B-36J-1-CF 52-2220 at NMUSAF, Wright-Patterson AFB, Ohio.

30 April 1959: Convair B-36J-1-CF Peacemaker, serial number 52-2220, landed at Wright-Patterson Air Force Base, Dayton, Ohio, completing the very last flight ever made by one of the giant Cold War-era bombers. It is on the collection of the National Museum of the United States Air Force.

Convair B-36J 52-2220 was among the last group of 33 B-36 bombers built. It was operated by an aircraft commander/pilot, co-pilot, two navigators, bombardier, two flight engineers, two radio operators, two electronic countermeasures operators and five gunners, a total 16 crewmembers. Frequently a third pilot and other additional personnel were carried.

Crewmebers pose in front of a B-36F, wearing capstan-type partial pressure suites for protection at high altitude. Front (L-R): G.L. Whiting, B.L. Woods, I.G. Hanten, and R.L. D’Abadie. Back (L-R):A.S. Witchell, J.D. McEachern, J.G. Parker and R. D. Norvell. (Jet Pilot Overseas)
Crew members pose in front of a Convair B-36F-1-CF Peacemaker, 49-2669, wearing David Clark Co. S-2 capstan-type partial pressure suits and early K-1 “split shell” 2-piece helmets for protection at high altitude. Front (L-R): G.L. Whiting, B.L. Woods, I.G. Hanten, and R.L. D’Abadie. Back (L-R):A.S. Witchell, J.D. McEachern, J.G. Parker and R. D. Norvell. (Jet Pilot Overseas)

The bomber is 162 feet, 1 inch (49.403 meters) long with a wingspan of 230 feet (70.104 meters) and overall height of 46 feet, 9 inches (14.249 meters). The empty weight is 171,035 pounds (77,580 kilograms) and combat weight is 266,100 pounds (120,700 kilograms). Maximum takeoff weight is 410,000 pounds (185,973 kilograms).

The B-36J has ten engines. There are six air-cooled, supercharged 4,362.49 cubic-inch-displacement (71.49 liter) Pratt & Whitney Wasp Major C6 (R-4360-53) four-row, 28-cylinder radial engines placed inside the wings in a pusher configuration. These had a compression ratio of 6.7:1 and required 115/145 aviation gasoline. The R-4360-53 had a Normal Power rating of 2,800 horsepower at 2,600 r.p.m. Its Military Power rating was 3,500 horsepower at 2,800 r.p.m., and 3,800 horsepower at 2,800 r.p.m. with water injection—the same for Takeoff. The engines turned three-bladed Curtiss Electric constant-speed, reversible propellers with a diameter of 19 feet, 0 inches (5.791 meters) through a 0.375:1 gear reduction. The R-4360-53 is 9 feet, 9.00 inches (2.972 meters) long, 4 feet, 7.00 inches (1.397 meters) in diameter, and weighs 4,040 pounds (1,832.5 kilograms).

Four General Electric J47-GE-19 turbojet engines are suspended under the wings in two-engine pods. The J47 is a  single-shaft axial-flow turbojet engine with a 12-stage compressor section, 8 combustion chambers, and single-stage turbine. The J47-GE-19 was modified to run on gasoline and was rated at 5,200 pounds of thrust (23.131 kilonewtons).

The B-36J had a cruise speed of 203 miles per hour (327 kilometers per hour) and a maximum speed of 411 miles per hour (661 kilometers per hour) at 36,400 feet (11,905 meters) . The service ceiling was 39,900 feet (12,162 meters) and its range was 6,800 miles (10,944 kilometers) with a 10,000 pound (4,536 kilogram) bomb load. The maximum range was 10,000 miles (16,093 kilometers).

Convair B-36J-1-CF Peacemaker 52-2220. (San Diego air and Space Museum Archives)

Designed during World War II, nuclear weapons were unknown to the Consolidated-Vultee engineers. The bomber was built to carry up to 86,000 pounds (39,009 kilograms) of conventional bombs in two bomb bays. It could carry the 43,600 pound (19,776.6 kilogram) T-12 Cloudmaker, a conventional explosive earth-penetrating bomb, or several Mk.15 thermonuclear bombs. By combining the bomb bays, one Mk.17 25-megaton thermonuclear bomb could be carried.

For defense, the B-36J had six retractable defensive gun turrets and gun turrets in the nose and tail. All 16 guns were remotely operated. Each position mounted two M24A1 20 mm autocannons. 9,200 rounds of ammunition were carried.

Between 1946 and 1954, 384 B-36 Peacemakers were built. They were never used in combat. Only five still exist.

Convair B-36J-1-CF 52-2220 being moved from Building 1 to Building 3 at the National Museum of the United States Air Force, October 2002. (U.S. Air Force)

© 2017, Bryan R. Swopes

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