Tag Archives: Strategic Bomber

8 August 1946

Convair XB-36 Peacemaker 42-13570 engine run-up
The prototype Consolidated-Vultee XB-36, 42-13570, stands at the end of the runway with all six engines running. (U.S. Air Force)

8 August 1946: At Fort Worth, Texas, the Consolidated-Vultee Aircraft Corporation XB-36 prototype, 42-13570, made its first flight. Convair test pilots Beryl Arthur Erickson and G.S. “Gus” Green, along with Chief Flight Test Engineer James D. “J.D.” McEachern, were in the cockpit and six other crewmembers were aboard.

Chief Test Pilot Beryl Arthur Erickson. (Convair)

In a 1992 interview published in Code One Magazine, Erickson said that he and his crew had been ready to take off at 5 a.m., but they didn’t get their release until noon. The Texas summer temperature was 100 degrees (37.8 °C.), but inside the cockpit, the temperature was 140° F. (60 °C.) The engines were overheating and the oil pressure was low. When they pushed the throttles forward, the XB-36 accelerated smoothly and lifted off at 110 knots (126.6 miles per hour, 203.7 kilometers per hour). The retired test pilot said, “The XB-36 controlled nicely in the takeoff run and in the transition to steady climb. We flew conservatively with the gear down. The flight was uneventful and lasted thirty-eight minutes.”

The B-36 was the largest and heaviest airplane built up to that time. It was designed as a long-range heavy bomber, able to reach targets on the European continent from the United States and return, should England fall to Nazi Germany during World War II. With the end of the war, its purpose was changed to that of a long range strategic bomber, carrying large nuclear weapons that weren’t even imagined when the design process had begun.

A size comparison between the Convair XB-36 prototype and a Boeing B-29 Superfortress.
A size comparison between a Boeing B-29-55-BA Superfortress, 44-84017, and the Consolidated-Vultee XB-36 prototype. (U.S. Air Force)

The XB-36 had a wing span of 230 feet (70.104 meters), nearly 90 feet longer than that of the B-29 Superfortress that it would replace. It was 162 feet, 1 inch (49.403 meters) long and 46 feet, 8 inches (14.224 meters) to the tip of the vertical fin. The prototype’s empty weight was 131,740 pounds (59,756 kilograms), and it had a maximum gross weight of 276,506 pounds (125,421 kilograms).

The XB-36 was powered by six air-cooled, supercharged, 4,362.49 cubic-inch-displacement (71.489 liter) Pratt & Whitney Wasp Major TSB1P-G (R-4360-25) 28-cylinder four-row radial engines, with a normal power rating of 2,500 horsepower at 2,550 r.p.m. to 5,000 feet (1,524 meters), and 3,000 horsepower at 2,700 r.p.m. for takeoff. They were mounted inside the wings. The engines were arranged in a “pusher” configuration with intake and cooling air entering through inlets in the wing leading edge. They drove three-bladed propellers with a diameter of 19 feet (5.8 meters) through a 0.381:1 gear reduction. The R-4360-25 was 9 feet, 1.75 inches (2.788 meters) long 4 feet, 4.50 inches (1.334 meters) in diameter, and weighed 3,483 pounds (1,580 kilograms).

The airplane’s maximum speed was 346 miles per hour (557 kilometers per hour) and cruising speed was 216 miles per hour (348 kilometers per hour). It had an estimated range of 9,500 miles (15,290 kilometers) with a 10,000 pound (4,536 kilogram) bomb load.

The prototype Convair XB-36, 42-13570, lifts off the runway at Fort Worth, Texas. (U.S. Air Force)
The prototype Consolidated-Vultee XB-36, 42-13570, lifts off the runway at Fort Worth, Texas. (U.S. Air Force)

After testing, improvements were incorporated into the second prototype, YB-36 42-13571. In June 1948, the XB-36 was modified with R-4360-41 engines, and the main landing gear was changed from a single-wheel design to a 4-wheel bogie. With these and other changes the XB-36 was redesignated YB-36A. It was used for continued testing for the next several years, but was eventually stripped of its engines and equipment and used for firefighter training at the adjacent Carswell Air Force Base.

The YB-36 was selected for production as the B-36A Peacemaker. The B-36 series was produced in both bomber and reconnaissance versions and was in front line service from 1949 to 1959. Beginning with the B-36D, four turbojet engines were mounted beneath the wings in pods similar to those on the Boeing B-47 Stratojet, greatly increasing the bomber’s performance. A total of 384 were built. Only five still exist. The Peacemaker was never used in combat.

The Convair XB-36 in flight. (U.S. Air Force)
The Consolidated-Vultee XB-36, 42-13570, in flight. (U.S. Air Force)

© 2018, Bryan R. Swopes

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5 August 1954

The first production B-52A takes off from Boeing Field, 5 August 1954. (Boeing)

5 August 1954: The first production Boeing B-52A Stratofortress, B-52A-1-BO 52-001, made its first flight from Boeing Field, Seattle, Washington.

Boeing B-52A Stratofortress 52-001 rollout, 18 March 1954. (Boeing)

The B-52A differed from the XB-52 and YB-52 in that its cockpit was arranged for side-by-side seating, rather than the B-47-type tandem arrangement of the prototypes. It also had an inflight refueling system allowing it to receive fuel from an airborne KC-97 tanker.

52-001 was used as a service test aircraft along with sister ships 52-002 and 52-003. It was scrapped at Tinker Air Force Base in 1961.

Boeing B-52A-1-BO Stratofortress 52-001 during its first flight, 5 August 1954. (U.S. Air Force)

© 2015, Bryan R. Swopes

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13 July 1968

General Dynamics FB-111A 67-0159, the first production aircraft. (U.S. Air Force)

13 July 1968: The first production General Dynamics FB-111A supersonic strategic bomber successfully completed a 30-minute maiden flight at Carswell Air Force Base, Fort Worth, Texas. The FB-111A differed from the F-111A fighter bomber with the substitution of a larger wing, originally designed for the F-111B, giving the bomber a 7 foot (2.134 meter) increase in wingspan. The landing gear was strengthened, the bomb bay enlarged, and it had more powerful engines.

Aardvark (Orycteropus afer)

The airplane’s very long nose earned the nickname “Aardvark,” but this did not become official until 1996.

67-0159 was delivered to the U.S. Air Force 4 September 1968 and assigned to the Air Force Flight Test Center, Edwards Air Force Base, California. (The first six production airplanes were used for flight testing.)

67-0159 was later converted to the F-111G configuration. In 1980 it was sent to the Sacramento Air Logistics Center to test weapons modifications and received a spectacular white and orange paint scheme. It was retired in 1990. 67-0159 is in the collection of the National Museum of the United States Air Force. It is on loan and now on display at the Aerospace Museum of California, Sacramento, California.

General Dynamics FB-111A-CF (F-111G) 67-159

The General Dynamics FB-111A is a two-place, twin-engine, strategic bomber with variable-sweep wings, assigned to the Strategic Air Command. It is 73.54 feet (22.415 meters) long. The wingspan varies from a maximum 70.0 feet (21.336 meters) when fully extended, and a minimum 33.96 feet (10.351 meters) when swept fully aft. Overall height is 17.04 feet (5.194 meters).

The wings of the FB-111A have a total area of 550 square feet (51.10 square meters). When fully extended, the wings’ leading edges are swept aft to 16.0°. The angle of incidence at the root is +1° and -3° at the tip. There is 1.0° dihedral.

The Aardvark’s empty weight is 47,481 pounds (21,537 kilograms). Normal maximum takeoff weight is 116,115 pounds (52,669 kilograms), and the maximum overload takeoff weight is or 119,243 pounds (54,088 kilograms).

The aircraft is powered by two Pratt & Whitney TF30-P-107 engines. This is a two-spool axial-flow turbofan engine with afterburner. It has a 3-stage fan section, 13-stage compressor section (6 low- and 7 high-pressure stages) and 4-stage turbine (1 high- and 3 low-pressure stages). The -107 has a maximum continuous power rating of 10,800 pounds of thrust (48.041 kilonewtons) at 14,150 r.p.m., N2 (static thrust, at Sea Level), and a maximum power rating of 20,350 pounds (90.521 kilonewtons) at 14,550 r.p.m., N2 (45 minute limit) The T30-P-107 is 3 feet, 2.12 inches (0.968 meters) in diameter, 20 feet, 1.4 inches (6.132 meters) long,  and weighs 4,121 pounds (1,869 kilograms).

The FB-111A has an average cruise speed of 415–442 knots (478–509 miles per hour/769-819 kilometers per hour), depending on the mission profile. It’s maximum speed at 50,000 feet (15,240 meters) is 1,262 knots (1,452 miles per hour/2,337 kilometers per hour)—Mach 2.20. The bomber’s service ceiling varies from 50,390 feet to 56,380 feet (15,359–17,185 meters), again, depending on the mission profile. The maximum combat range is 4,920 nautical miles (5,662 statute miles/9,112 kilometers). The airplane can carry as many as six 600 gallon (2,271 liter) external tanks on underwing pylons. This gives the Aardvark a maximum ferry range of 4,313 nautical miles (4,963 statute miles/7,988 kilometers).

General Dynamics FB-111A 67-163, the fifth production airplane, loaded with four AGM-69 SRAM missiles. The dots on the missiles and airplane are for precise tracking from ground stations. (U.S. Air Force)

The FB-111A could carry weapons in an internal bomb bay or on underwing hardpoints. It could be armed with up to 37,500 pounds (17,010 kilograms) of conventional bombs; or six AGM-69A Short Range Attack Missiles (SRAM). The Aardvark could carry maximum of six nuclear weapons (B-43, B-57 or B-61).

General Dynamics YFB-111A 63-9783, the prototype strategic bomber variant. (U.S. Air Force)

In addition to a prototype (63-9783, which was converted from the last production F-111A) General Dynamics built 76 FB-111A strategic bombers. With the introduction of the Rockwell B-1B Lancer, the FB-111As remaining in service were converted to F-111G tactical fighter bombers. They were retired by 2003.

The Royal Australian Air Force bought 15 of the F-111Gs. By 2007, these had also been taken out of service.

Two General Dynamics FB-111As in formation, 1 December 1983. (MSGT Buster Kellum, U.S. Air Force)

© 2018, Bryan R. Swopes

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29 June 1955

The first operational Boeing B-52 Stratofortress, RB-52B-15-BO 52-8711. (U.S. Air Force)
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 new long-range heavy bomber 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.
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 RB-52B’s empty weight was 162,969 pounds (73,921 kilograms), with a combat weight of 257,900 pounds (116,981 kilograms) and a maximum takeoff weight of 390,000 pounds (176,901 kilograms). (MTOW was later increased to 420,000 pounds.)

The bomb bay of this RB-52B Stratofortress, 52-8012, 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 517 knots (595 miles per hour/957 kilometers per hour) at 35,000 feet (10,668 meters). The maximum speed was 542 knots (624 miles per hour/1,004 kilometers per hour) at 19,500 feet (5,944 meters). The service ceiling at combat weight was 47,600 feet (14,508 meters).

The RB-52B had a maximum fuel capacity of 37,385 gallons (141,518 liters). Its maximum ferry range was 6,460 nautical miles (7,434 statute miles/11,964 kilometers). With a 10,000 pound (4,536 kilogram) bomb load, the RB-52B had a combat radius of 3,110 nautical miles (3,579 miles/5,760 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 in excess of 4,000 rounds per minute.

The B-52B could carry twenty-seven 750 pound (340 kilogram) bombs, or two 25,000 pound (11,340 kilogram) Special Weapons (thermonuclear bombs).

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 remain 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)
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)

© 2018, Bryan R. Swopes

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24 June 1993

Boeing B-52 Stratofortress bombers in storage at Davis-Monthan Air Force Base, Tucson, Arizona. (Unattributed)
Boeing B-52 Stratofortress bombers in storage at Davis-Monthan Air Force Base, Tucson, Arizona. (Unattributed)

24 June 1993: In compliance with an arms control treaty between the United States and the Soviet Union, the Aerospace Maintenance and Regeneration Center (AMARC) at Davis-Monthan Air Force Base, Tucson, Arizona, immediately began the destruction of 363 Boeing B-52 Stratofortress strategic bombers.

Boeing B-52s awaiting destruction at Davis-Monthan AFB. (Unattributed)

© 2015, Bryan R. Swopes

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