Tag Archives: Bomber

29 June 1955

June 29, 2024Aviation52-8711, 93rd Bombardment Wing (Heavy), Boeing RB-52B Stratofortress, Bomber, Brigadier General William Emanuel Eubank Jr., Browning Aircraft Machine Gun Caliber .50 AN-M3, Castle Air Force Base, Pratt & Whitney J57-P-1W, Pratt and Whitney, RB-52B-15-BO, Reconnaissance Bomber, Strategic Air Command, Strategic BomberBryan Swopes

The first operational Boeing B-52 Stratofortress, RB-52B-15-BO 52-8711. (U.S. Air Force)

29 June 1955: The first operational Boeing B-52 Stratofortress, RB-52B-15-BO 52-8711, was delivered to the 93rd Bombardment Wing, Heavy, at Castle Air Force Base, Merced, California. The bomber was accepted from Boeing at Larson Air Force Base, Moses Lake, Washington, by the 93rd’s commanding officer, Brigadier General William Emanuel Eubank, Jr., U.S. Air Force, before flying to Castle. The new long-range heavy bombers would replace the 93rd’s Boeing B-47 Stratojets.

Fifty B-52Bs were built by Boeing at its Plant 2, Seattle, Washington. Twenty-seven of these were RB-52B reconnaissance bombers. They were designed to accept a pressurized electronic intelligence and photographic reconnaissance capsule with a two-man crew that completely filled the bomb bay. Without the capsule aboard, the RB-52s were capable of the same bombing missions as their sister B-52Bs. The change could be made within a few hours.

Pressurized two-man RB-52 reconnaissance pod. (U.S. Air Force)

The B-52B/RB-52B was operated by a six-man flight crew for the bombing mission, and eight for reconnaissance. These were the aircraft commander/pilot, co-pilot, navigator, radar navigator/bombardier, electronic warfare officer, and gunner, plus two reconnaissance technicians when required.

The airplane was 156.6 feet, (47.7 meters) long with a wingspan of 185.0 feet (56.4 meters) and overall height of 48.3 feet (14.7 meters). The wings were mounted high on the fuselage (“shoulder-mounted”) to provide clearance for the engines which were suspended on pylons. The wings’ leading edges were swept aft to 36° 54′. Their angle of incidence was 6° and there was 2° 30′ dihedral. The wing area was 4,000 square feet (372 square meters). The B-52B’s calculated empty weight was 164,081 pounds (74,426 kilograms), with a combat weight of 272,000 pounds (123,377 kilograms) and a maximum takeoff weight of 420,000 pounds (190,509 kilograms).

The bomb bay of this RB-52B-10-BO Stratofortress, 52-012, is open, revealing the reconnaissance pod. (U.S. Air Force)

Early production B-52Bs were powered by eight Pratt & Whitney J57-P-1W turbojet engines, while later aircraft were equipped with J57-P-19W and J57-P-29W or WA turbojets. The engines were grouped in two-engine pods on four under-wing pylons. The J57 was a two-spool, axial-flow engine with a 16-stage compressor section (9 low- and 7-high-pressure stages) and a 3-stage turbine section (1 high- and 2 low-pressure stages). The J57-PW-1 engines had a Normal Power rating of 8,250 pounds of thrust (32.698 kilonewtons) at 9,720 r.p.m., N1, continuous; Military Power, 9,500 pounds thrust (42.258 kilonewtons) at 9,950 r.p.m., N1, for 30 minutes; and Maximum Power, 11,100 pounds of thrust (49.375 kilonewtons) with water injection, at 9,950 r.p.m., N1, 5 minute limit. The J57-PW-1 was 3 feet. 4.5 inches (1.029 meters) in diameter, 13 feet, 1.2 inches (3.993 meters) long, and weighed 4,210 pounds (1,910 kilograms).

Boeing RB-52B-10-BO Stratofortress 52-013. (U.S. Air Force)

The B-52B/RB-52B had a cruise speed of 453 knots (521 statute miles per hour/839 kilometers per hour) at 34,950 feet (10,653 meters). The maximum speed was 551 knots (634 miles per hour/1,020 kilometers per hour) at 20,300 feet (6,187 meters). The service ceiling at combat weight was 47,700 feet (14,539 meters). The maximum service ceiling was 55,700 feet (16,977 meters).

The B/RB-52B had a maximum fuel capacity of 37,550 gallons (142,142 liters) of JP-4. It also carried 360 gallons (1,363 liters) of water for injection during takeoff. The bomber’s maximum ferry range was 6,380 nautical miles (7,342 statute miles/11,816 kilometers). With a 10,000 pound (4,536 kilogram) bomb load, the B/RB-52B had a combat radius of 3,070 nautical miles (3,533 miles/5,686 kilometers). With inflight refueling, the bomber’s range was world-wide.

Tail gun turret of an early B-52 Stratofortress — B-52 tail gun turret

Defensive armament consisted of four Browning Aircraft Machine Guns, Caliber .50, AN-M3, mounted in a tail turret with 600 rounds of ammunition per gun. These guns had a combined rate of fire of 4,800 rounds per minute.

The B-52B could carry twenty-seven 1,000 pound (454 kilogram) bombs, or two Mk.21 17,000 pound (7,711 kilogram) Special Weapons (thermonuclear bombs). The maximum bomb load was 43,000 pounds (19,505 kilograms). (At the time 52-8711 entered service, only fission weapons were available. The most powerful of these was the variable yield Mk.6, which could produce a maximum 160 kilotons of energy.)

Boeing manufactured 744 B-52 Stratofortress bombers, with the final one rolled out at Wichita, Kansas, 22 June 1962. As of June 2016, 75 B-52H bombers remained in service with the United States Air Force.

RB-52B 52-8711 remained in active service until 29 September 1965. Today it is on display at the Strategic Air and Space Museum, Ashland, Nebraska.

A Strategic Air Command alert crew runs to man their bomber, Boeing RB-52B-15-BO Stratofortress 52-8711, 22 Bombardment Wing (Heavy), the first operational B-52, at March Air Force Base, California, 1965. (U.S. Air Force)

28 June 1945

June 28, 2024Aviation44-51928, B-24M-30-FO, Bomber, Consolidated B-24 Liberator, Ford B-24 Liberator, Ford Motor Company, Willow Run Airplane Plant, Willow Run Bomber Plant, World War IIBryan Swopes

28 June 1945: The very last of 18,482 B-24 Liberator very long range heavy bombers rolled off the assembly line at Ford’s Willow Run Aircraft Plant, located between Belleville and Ypsilanti, Michigan.

More B-24s were built than any other American aircraft type. They were produced by the designer, Consolidated Aircraft, at its San Diego, California and Fort Worth, Texas plants; by Douglas Aircraft at Tulsa, Oklahoma; North American Aviation at Dallas, Texas; and by Ford Willow Run.

Ford built 6,972 B-24s in 776 days and produced kits for 1,893 more to be assembled by the other manufacturers. The Willow Run plant completed a B-24 every 63 minutes.

The last B-24 built was this B-24M, 44-51928, at the Ford Willow Run plant. (The Henry Ford) — The last B-24 built was this B-24M-30-FO Liberator, 44-51928, at the Willow Run bomber plant. (The Henry Ford THF10153 Ford Motor Co. Willow Run Bomber Plant)

44-51928 was flown directly to a storage facility, then later, to the Reconstruction Finance Corporation site at Kingman, Arizona, where it was scrapped.

26 June 1948

June 26, 2024Aviation44-92004, 7th Bombardment Wing Very Heavy, B-36A-1-CF, Bomber, Carswell Air Force Base, Cold War, Consolidated-Vultee Aircraft Corporation, Convair B-36A Peacemaker, Convair RB-36E, Convair RB-36E Peacemaker, Convair YB-36A Peacemaker, Pratt & Whitney Wasp Major R-4360 Pusher (R-4360-25), Strategic Air CommandBryan Swopes

Convair B-36A-1-CF (S/N 44-92004, the first -A model built) in flight. (U.S. Air Force photo) — Convair B-36A-1-CF 44-92004, the first B-36A built. (U.S. Air Force)

26 June 1948: The 7th Bombardment Wing, Very Heavy, at Carswell Air Force Base, Fort Worth, Texas, received the United States Air Force’s first Consolidated-Vultee Aircraft Corporation (“Convair”) B-36A, a six-engine, very long range heavy bomber. Its mission was to serve as a nuclear-capable deterrent until the Boeing B-52 Stratofortress came into service five years later. A total of 22 B-36As were delivered by February 1949. These were not armed and were used for crew training. Most were later converted by Convair to RB-36E reconnaissance bombers, beginning in 1950.

The B-36A differed from the XB-36 prototype in several areas, but two features were the most apparent: The cockpit had been completely revised and now covered by a large dome. The single-wheel main landing gear was replaced by four-wheel bogies to better spread the airplane’s weight over the runway surface.

A crew of thirteen airmen with their Convair B-36A-10-CF Peacemaker, 44-92014. (LIFE Magazine via Jet Pilot Overseas) — A crew of thirteen airmen with their Convair B-36A-10-CF Peacemaker, 44-92013, at Carswell AFB, 1949. (LIFE Magazine via Jet Pilot Overseas)

The B-36A was 162.1 feet (49.4 meters) long with a wingspan of 230.0 feet (70.1 meters) and overall height of 46.8 feet (14.3 meters). The wings had 2° dihedral, an angle of incidence of 3° and -2° twist. The wings’ leading edges were swept aft to 15° 5′. The airplane’s total wing area was 4,772 square feet (443.33 square meters). Its empty weight was 135,020 pounds (61,244 kilograms). The combat weight was 212,800 pounds (96,524 kilograms) and maximum takeoff weight (MTOW) was 310,380 pounds (140,786 kilograms).

Convair B-36A 44-92015 at Carswell Air Force Base.

The initial production version of the Peacemaker was powered by six air-cooled, supercharged, 4,362.5 cubic-inch-displacement (71.489 liter) Pratt & Whitney Wasp Major R-4360 Pusher (R-4360-25) four-row, 28-cylinder radial engines rated at 2,500 horsepower at 2,550 r.p.m. at 37,000 feet (11,278 meters), and 3,000 horsepower at 2,700 r.p.m. for takeoff. Each engine drove a 19-foot (5.791 meter) three-bladed propeller through a 0.381:1 gear reduction. The R-4360-25 was 9 feet, 1.75 inches (2.788 meters) long and 4 feet, 4.50 inches (1.334 meters) in diameter. It weighed 3,483 pounds (1,580 kilograms).

The six radial engines gave the bomber a maximum speed of 300 knots (345 miles per hour/556 kilometers per hour) at 31,600 feet (9,632 meters). It took 53 minutes for the giant airplane to climb to an altitude of 20,000 feet (6,396 meters). The service ceiling for the B-36A was 39,100 feet (11,918 meters), and combat ceiling was 35,800 feet (10,912 meters). The ferry range was 9,136 miles (14,702 kilometers).

The B-36As initially carried no defensive armament. The maximum bomb load was seventy-two 1,000 pound bombs (total, 72,000 pounds/32,659 kilograms) carried in four internal bomb bays. With a bomb load of 10,000 pounds (4,536 kilograms), the B-36A had a combat radius of 3,370 nautical miles (3,878 miles/6,241 kilometers).

Designed during World War II when nuclear weapons were unknown to aeronautical engineers, the bomber was designed to carry up to 86,000 pounds (39,009 kilograms) of conventional bombs. It could carry a single 43,600 pound (19,777 kilogram) T-12 Cloudmaker, a conventional explosive earth-penetrating bomb, or, later, several Mk.15 thermonuclear bombs. By combining the bomb bays, one Mk.17 15-megaton thermonuclear bomb could be carried.

The sixteenth B-36A, 44-92020, after conversion to the RB-36E reconnaissance configuration. (U.S. Air Force)

The RB-36E reconnaissance bomber carried a crew of 22. The radial engines were upgraded to R-4360-41s which increased takeoff horsepower with water injection to 3,500 at 2,700 r.p.m. at Sea Level. Four General Electric J47-GE-19 turbojet engines were added in two two-engine pods at the outer end of each wing. These changes significantly increased the airplane’s maximum speed and altitude capability and reduced the required takeoff distance by 25%. Fourteen reconnaissance cameras were installed. There were four additional radomes on the belly and numerous external antennas for electronic intelligence gathering.

The empty weight of the RB-36E increased to 164,238 pounds (74,497 kilograms) and the maximum takeoff weight to 370,000 pounds (167,829 kilograms).

The maximum speed of the RB-36E was 363 knots (418 miles per hour/672 kilometers per hour) at 38,200 feet (11,643 meters). Its service ceiling was 46,400 feet (14,143 meters).

The reconnaissance bomber carried eighty 188 pound (85.3 kilogram) T-56 photo flash bombs. Defensive armament consisted of sixteen M24A1 20 mm autocannon in five remotely-operated turrets. 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.

The first Consolidated-Vultee B-36A, 44-92004, was flown to Wright Field, Dayton, Ohio, for structural testing. Redesignated YB-36A, it was tested to destruction.

Convair YB-36 (B-36A) 004 under structural testing at Wright Field. (U.S. Air Force) — Convair YB-36A 44-92004 under structural testing at Wright Field. (U.S. Air Force)

The name, “Peacemaker,” was suggested by a Convair employee. It is a reference to the Colt Model 1873 Single-Action Army® revolver, the classic “six-shooter” of the American frontier, which is also known as the Peacemaker®.

25 June 1946

June 25, 2024Aviation42-13603, Bomber, Dale Schroeder, First Flight, Flying Wing, Jack Northrop, Max R. Stanley, Muroc Army Air Field, Northrop Aircraft Inc., Northrop XB-35, Orva H Douglas Jr., Pratt & Whitney R-4360-17, Pratt & Whitney R-4360-21, Pratt & Whitney Wasp Major TSB1P-RGD, PrototypeBryan Swopes

Northrop XB-35 taking of at Northrop Field, Hawthorne, California. (U.S. Air Force) — Northrop XB-35 taking off at Northrop Field, Hawthorne, California. (U.S. Air Force)

Max R. Stanley (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers))

25 June 1946: Northrop Aircraft, Inc., experimental test pilot Max R. Stanley, flight test engineer Dale Schroeder and Orva H Douglas, Jr., flight engineer, made the first flight of the Northrop XB-35 “Flying Wing,” serial number 42-13603. They took off from the factory’s airfield at Hawthorne, California, and flew the prototype bomber to Muroc Army Air Field (now, Edwards Air Force Base). The initial flight lasted 55 minutes.

The Los Angeles Times reported:

Gigantic Flying Wing Triumphs in First Flight

Northrop 110,000-Pound Superbomber Soars 44 Minutes, makes Perfect Landing

Unleashed into the future, a huge and spectral devilfish bellowed up from the earth yesterday and soared eastward toward the morning sun—Northrop’s malevolent Flying Wing superbomber on her maiden test flight, Forty-four minutes later the ship made a perfect landing at Muroc Army Airfield.

Eerie, almost supernatural, she trundled to the west end of Northrop’s mile-long Hawthorne runway as the sun burned away the morning mists.

Thundering Take-off

For 45 minutes she stood motionless, a 172-foot knife blade, while her four 3000 h.p. engines turned eight coaxial pusher propellers into life.Then at 10:29 a.m. her whirling blades fused into blurred disks. Her thunder enveloped the field.

Interminably she seemed to hug the ground as Test Pilot Max Stanley held her charging 110,000 pounds down past the hangars, past the flight line, past the midfield control tower.

Monster Leaves Ground

For 30 thudding heartbeats—and as many seconds—the fantastic silver monster strained at the shackles of earth, hurtling at more than 100 m.p.h. toward the end of the runway.

Then at 3000 feet Stanley eased back the yoke. Sunlight skipped beneath the spinning wheels and the Wing lifted into her element under perfect control.

Vanishes Into Haze

In another 60 seconds she vanished into the haze, her wheels still down as Stanley gently tested her sinews. Below, and to the right of his bubble canopy, Co-pilot Fred C. Bretcher stared ahead through plexiglas in the leading edge, and just aft of the pilot, Engineer O. H. Douglas watched her pulse in the needles of scores of instruments.

In an easy climb, Stanley took the superbomber to 10,000 feet over the flat lands between the San Gabriel Mountains and the sea and then banked her slowly north and inland toward Muroc.

Settles to Runway

At the Muroc test field, the strip was cleared and ready. Spectators watched the incredible ship circle once and then gently settle to the runway as gently as a tuft of cotton and roll to stop in 3000 feet.”She handled beautifully,” grinned Stanley.

The outgrowth of years of engineering, she followed the secret testing of a parade of small wings, and her designer, John K. Northrop, is confident she’ll carry more bombs farther and faster than any other airplane ever built.

Fourteen more of the giants will be built under Northrop’s contract with the Army.

—Los Angeles Times, Vol. LXV, Wednesday Morning, 26 June 1946, Page 1, Columns 5 and 6

The Los Angeles Daily News reported:

Flying wing passes tests

Everybody who had anything to do with it was happy today over the 44-minute maiden flight of Northrop’s flying wing.

The bat-like plane, a 104-ton monster bomber, met all expectations during the 85-mile flight from Northrop Field to Muroc Army Air Base.

“The wing handled just as I expected it would,” veteran test pilot Max Stanley declared after landing the giant ship. “We were delighted with its performance and the plane fully came up to our expectations.”

Officials of Northrop Aircraft, who witnessed the initial take-off, said the flight had justified their confidence in the wing.

The ship, a tailess airplane with a bat-like appearance, is the latest in a series of 15 Northrop designed flying wings and was built at a cost of $13,000,000 for the army.

—Daily News, Wednesday, 26 June 1946, Page 3, Column 1

Flight test crew of Northrop's XB-35 at Northrop Field, Hawthorne, California, 1946. — The flight test crew of the Northrop XB-35 at Northrop Field, Hawthorne, California, 1946. Left to right, Dale Schroeder, flight test engineer; Orva H Douglas, Jr., flight engineer; and Max Stanley, test pilot. (Unattributed)

The XB-35 was designed as an aerodynamically efficient heavy bomber. It had a very unusual configuration for an aircraft of that time. There was no fuselage or tail control surfaces. The crew compartment, engines, fuel, landing gear and armament was contained within the wing. It was 53 feet, 1 inch (16.180 meters) long, with a wingspan of 172 feet (52.426 meters) and overall height of 20 feet, 1 inch (6.121 meters). The prototype weighed 89,560 pounds (40,624 kilograms) empty, with a gross weight of 180,000 pounds (81,647 kilograms).

The Wing defined the airplane. It had an aspect ratio of 7.4:1. The wing’s root chord was 37 feet, 6 inches (11.430 meters). The wing was 7 feet, 1.5 inches (2.172 meters) thick at the root. The tip chord was 9 feet, 4 inches (2.844 meters). There was 0° angle of incidence at the root, with -4° of twist, and 0° 53′ dihedral. The leading edge was swept aft 26° 57′ 48″, and the trailing edge, 10° 15′ 22″. The wing’s total area was 4,000 square feet (371.6 square meters).

This view of the Northrop XB-35 Flying W 42-13603 on the ramp at Muroc Air Force Base shows the pusher arrangement of four-bladed contra-rotating propellers. In the background, a turbojet-powered YB-49 is in a right bank.. (U,S. Air Force) — This view of the first prototype Northrop XB-35, 42-13603, the “Flying Wing,” on the ramp at Muroc Air Force Base shows the pusher arrangement of four-bladed contra-rotating propellers. In the background, a turbojet-powered Northrop YB-49 is in a steep bank. (U.S. Air Force)

The XB-35 was powered by four air-cooled, supercharged and turbocharged 4,362.49 cubic-inch-displacement (71.49 liter) Pratt & Whitney Wasp Major TSB1P-RGD (R-4360-17 or -21) four-row 28-cylinder radial engines with a compression ratio of 7:1. The R-4360-17 was rated at 2,500 horsepower at 2,550 r.p.m at 40,000 feet (12,192 meters), and 3,000 horsepower at 2,700 r.p.m., for takeoff. It could maintain the takeoff rating to an altitude of 40,000 feet (12,192 meters) for Military Power. The engines were mounted completely inside the wing and were connected to a remote propeller drive unit by drive shafts. The engines were direct drive, while the propeller gear boxes had a 0.381:1 reduction ratio. The R-4360-17 was 5 feet, 7.00 inches (1.702 meters) long, 4 feet, 4.50 inches (1.334 meters) in diameter, and weighed 3,306 pounds (1,499.6 kilograms).

Northrop XB-35 42-13603 in flight with early contra-rotating propellers. (U.S. Air Force)

The propellers were dual three-bladed contra-rotating assemblies located in pusher configuration at the wing’s trailing edge. (These were quickly changed to four-bladed propellers, which were smoother in operation and more efficient.)

Northrop XB-35 42-13603. (U.S. Air Force)

The XB-35 had a cruising speed of 183 miles per hour (295 kilometers per hour) at 39,700 feet (12,100 meters) and maximum speed was 391 miles per hour (629 kilometers per hour) at 35,000 feet (10,668 meters). With a crew of nine, and another six relief crewmembers, the bomber had a range of 8,150 miles (13,116 kilometers).

The production Northrop B-35 would have been armed with twenty .50-caliber machine guns for defense and a maximum bomb load of 51,200 pounds (23,223 kilograms).

Underside of a Northrop XB-35. (U.S. Air Force)

The XB-35 was plagued by unresolved problems with the propeller gear boxes which eventually forced Jack Northrop to ground the aircraft until the engine and propeller manufacturers could come up with a solution, which was to change from piston to turbojet engines. That version became the YB-49. Because of the continuing problems, though, 42-13603 was grounded after only 19 flights, and with its sister ship, XB-35 42-38323, was scrapped in August 1949.

A Northrop XB-35 in flight. (U.S. Air Force)

22 June 1962

June 22, 2024Aviation61-0040, B-52H-175-BW, Boeing B-52H Stratofortress, Boeing Military Airplane Company, Bomber, General Electric M61 Vulcan, Last B-52, Pratt & Whitney TF33-P-3, s/n 464467, Strategic BomberBryan Swopes

The last of 744 Boeing B-52 Stratofortress bombers, B-52H-175-BW, 61-0040, is rolled out at the Boeing plant at Wichita, Kansas. (Boeing)

22 June 1962: The last of 744 Boeing B-52 Stratofortress strategic bombers, B-52H-175-BW, serial number 61-0040, was rolled out at the Boeing Military Airplane Company plant in Wichita, Kansas.

The U.S. Air Force contracted 62 B-52H Stratofortresses, serial numbers 60-0001 through 60-0062, on 6 May 1960. A second group of 40, serials 61-0001 through 61-0040, were ordered later. All were built at the Boeing Wichita plant.

The B-52H, like the B-52G, is a re-engineered aircraft, structurally different from the XB-52, YB-52, and B-52A–B-52F Stratofortress variants. It is lighter, carries more internal fuel, giving it a longer unrefueled range, and is strengthened for low-altitude flight. The shorter vertical fin is intended to prevent the losses caused by the original tall fin in turbulent air. The B-52H is equipped with quieter, more efficient turbofan engines.

Boeing B-52H-175-BW Stratofortress 61-0040 in camouflage. (U.S. Air Force) — Boeing B-52H-175-BW Stratofortress 61-0040 in camouflage, assigned to 2nd Air Force, circa 1975. (U.S. Air Force)

The B-52H was developed to carry four Douglas GAM-87 Skybolt air-launched ballistic missiles on pylons mounted under the wings, inboard of the engines. The Skybolt was armed with a 1-megaton W-59 thermonuclear warhead. The program was cancelled, however, and the North American Aviation AGM-28 Hound Dog air-launched cruise missile was used instead. (Interestingly, the Hound Dog’s Pratt & Whitney J52-P-3 turbojet engine could be used to supplement the B-52’s takeoff thrust, and then refueled from the bomber’s tanks before being air-launched.)

The B-52H is a sub-sonic, swept wing, long-range strategic bomber. It was originally operated by a crew of six: two pilots, a navigator and a radar navigator, an electronic warfare officer, and a gunner. (The gunner was eliminated after 1991). The airplane is 159 feet, 4 inches (48.565 meters) long, with a wing span of 185 feet (56.388 meters). It is 40 feet, 8 inches (12.395 meters) high to the top of the vertical fin. The B-52H uses the vertical fin developed for the B-52G, which is 22 feet, 11 inches (6.985 meters) tall. This is 7 feet, 8 inches (2.337 meters) shorter than the fin on the XB-52–B-52F aircraft, but the fin’s chord is longer.

The wings of the B-52H have a total area of 4,000 square feet ( square meters). The leading edges are swept aft to 36° 58′. The angle of incidence is 6°, and there is 2° 30′ dihedral. (The wings are very flexible and exhibit pronounced anhedral when on the ground.) To limit twisting in flight, the B-52 has spoilers on top of the wings rather than ailerons at the trailing edges.

Boeing B-52H Stratofortress. (U.S. Air Force)

The bomber has an empty weight of 172,740 pounds (78,354 kilograms) and its Maximum Takeoff Weight (MTOW) is 488,000 pounds (221,353 kilograms).

The most significant difference between the B-52H and the earlier Stratofortresses is the replacement of the eight Pratt & Whitney J57-series turbojet engines with eight Pratt & Whitney Turbo Wasp JT3D-2 (TF33-P-3) turbofans, which are significantly more efficient. They are quieter and don’t emit the dark smoke trails of the turbojets. The TF-33 is a two-spool axial-flow turbofan engine with 2 fan stages, a 14-stage compressor section (7-stage intermediate pressure, 7-stage high-pressure) and and a 4-stage turbine (1-stage high-pressure, 3-stage low-pressure). The TF33-P-3 has a maximum continuous power rating of 14,500 pounds of thrust (64.499 kilonewtons) at 9,750 r.p.m., N1. Military Power, limited to 30 minutes, is 16,500 pounds (73.396 kilonewtons) at 10,000 r.p.m., N1. Each engine produces a maximum of 17,000 pounds of thrust (75.620 kilonewtons) at 10,050 r.p.m., N1, with a 5-minute limit. The TF33-P-3 is 11 feet, 4.32 inches (3.4625 meters) long, 4 feet, 4.93 inches (1.3442 meters) in diameter and weighs 3,900 pounds (1,769 kilograms).

The B-52H has a cruise speed of 456 knots (525 miles per hour/845 kilometers per hour). It has a maximum speed, with Military Power, of 555 knots (639 miles per hour/1,028 kilometers per hour) at 20,700 feet (6,309 meters)—0.906 Mach. The service ceiling is 46,900 feet (14,295 meters). The unrefueled range is 8,000 miles (12,875 kilometers). With inflight refueling, its range is limited only by the endurance of its crew.

A Boeing B-52H Stratofortress during a deterrent patrol near the Democratic People's Republic of North Korea, 2016. (U.S. Air Force) — A Boeing B-52H Stratofortress during a deterrent patrol near the Democratic People’s Republic of North Korea, 2016. (U.S. Air Force)

The B-52H can carry a wide variety of conventional free-fall or guided bombs, land-attack or anti-ship cruise missiles, and thermonuclear bombs or cruise missiles. These can be carried both in the internal bomb bay or on underwing pylons. The bomb load is approximately 70,000 pounds (31,751 kilograms).

The B-52H was equipped with a General Electric M61 Vulcan 20 mm six-barreled rotary cannon (a “Gatling gun”) in a remotely-operated tail turret. The gun had a rate of fire of 4,000 rounds per minute, and had a magazine capacity of 1,242 rounds. After 1991, the gun and its radar system were removed from the bomber fleet. The flight crew was reduced to five.

The B-52H was armed with a 20 mm M61 Vulcan 6-barreled cannon in place of the four .50-caliber machine guns of the earlier variants.

102 B-52Hs were built by Boeing Wichita. Beginning in 2009, eighteen B-52H bombers were placed in climate-controlled long term storage at Tinker Air Force Base, Oklahoma. In 2014, the entire fleet began a major avionics upgrade. As of December 2015, fifty-eight of the bombers remained in the active fleet of the United States Air Force and eighteen are assigned to the Air Force Reserve.

Recently, a B-52H-156-BW Stratofortress, 61-0007, Ghost Rider, was returned to operational status after eight years in storage at Davis-Monthan Air Force Base, Tucson, Arizona. 45,000 man-hours were required to restore the bomber.

The B-52H is expected to remain in service until 2040.

62 years after roll-out, 61-0040 is still in service with the United States Air Force, assigned to the 23rd Bomb Squadron, 5th Bomb Wing, at Minot Air Force Base, North Dakota.

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