Tag Archives: Strategic Bomber

29 June 1955

Aviation, , , , , , , , , , , ,
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 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.
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)
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)

© 2023, Bryan R. Swopes

24 June 1993

Aviation, , , , , ,
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

22 June 1962

Aviation, , , , , , , , ,
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)
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.
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.

Boeing B-52H-175-BW Stratofortress 61-0040 parked at Andersen Air Force Base, Guam. While at Andersen, -1040 was maintained by crew chiefs Airman 1st Class Jordon Dyer, Staff Sgt. Timothy Beamesderfer, Staff Sgt. Jim Alcozer and Airman 1st Class Michael Lawhorn, 36th Expeditionary Aircraft Maintenance Squadron. The bomber flew 20 consecutive sorties without a maintenance abort. (Senior Airman Carlin Leslie, U.S. Air Force 120724-F-QZ836-001)

© 2020 Bryan R. Swopes

17 June 1986

Aviation, , , , , , , , , , , , ,
Boeing B-47E-25-DT Stratojet 52-166 is prepared to Depart NAWC China Lake. (U.S. Navy)
B-47E-25-DT Stratojet 52-166 is prepared to depart Armitage Field, NAWS China Lake, 17 June 1986. (U.S.  Air Force)

17 June 1986: After being returned to flyable condition, B-47E-25-DT Stratojet serial number 52-166, made the very last flight of a B-47 when it was flown by Major General John D. (“J.D.”) Moore and Lieutenant Colonel Dale E. Wolfe, U.S. Air Force, from the Naval Air Weapons Station China Lake in the high desert of Southern California, to Castle Air Force Base in California’s San Joaquin Valley, to be placed on static display.

52-166 had been built by the Douglas Aircraft Company at Air Force Plant No. 3, Tulsa, Oklahoma, in 1952. 52-166 had not been flown in twenty years, having sat in the Mojave Desert serving as a radar target. General Moore and Colonel Wolf were experienced B-47 pilots, though they hadn’t flown one in the same twenty years. Because the B-47 it had not been through a complete overhaul prior to the ferry flight, it was decided to leave the landing gear extended to avoid any potential problems.

During the 43 minute trip, the aircraft had several systems fail, including airspeed sensors, intercom, and partial aileron control. On approach to Castle Air Force Base, a 16 foot (4.9 meters) approach parachute was deployed. This created enough aerodynamic drag to slow the airplane while the early turbojet engines were kept operating at high power settings. These engines took a long time to accelerate from idle, making a go-around a very tricky maneuver. Releasing the chute allowed the airplane to climb out as the engines were already operating at high r.p.m.

B-47E-25-DT Stratojet 52-166 enroute Castle Air Force Base with a Lockheed T-33A Shooting Star chase. California’s Sierra Nevada Mountains are in the distance. (TSGT Michael Hagerty/U.S. Air Force)
Douglas-built B-47E-25-DT Stratojet 52-166 enroute Castle Air Force Base with a Lockheed T-33A Shooting Star chase, 17 June 1986. California’s Sierra Nevada Mountains are in the distance. (U.S. Air Force)

Designed by Boeing, the Stratojet was a high-subsonic speed strategic bomber and reconnaissance aircraft, in service from 1951 until 1977. The B-47 could fly higher and faster than jet fighters of the time, and it was also highly maneuverable. B-47E (Boeing Model 450-157-35) was flown by a two pilots in a tandem cockpit. A navigator/bombardier was at a station in the nose.

The B-47E Stratojet differed from the earlier B-47B primarily with upgraded engines and strengthened landing gear to handle an increase in maximum weight. The B-47E Stratojet is 107.1 feet (32.644 meters) long with a wingspan of 116.0 feet (35.357 meters), and an overall height of  28.0 feet (8.534 meters). The wings are shoulder-mounted and have a total area of 1,428 square feet (132.67 square meters). The wings’ leading edges are swept aft to 36° 37′. The angle of incidence is 2° 45′ and there is 0° dihedral (the wings were very flexible). The B-47E in standard configuration had an empty weight of 78,620 pounds (35,661 kilograms) and maximum takeoff weight of 200,000 pounds (90,718 kilograms).

The B-47E was powered by six General Electric J47-GE-25 turbojet engines in four nacelles mounted on pylons below the wings. This engine has a 12-stage axial-flow compressor, eight combustion chambers, and single-stage turbine. The -25 has a continuous power rating of 5,320 pounds of thrust (23.665 kilonewtons) at 7,630 r.p.m., at Sea Level; Military Power, 5,670 pounds (25.221 kilonewtons) at 7,800 r.p.m. (30 minute limit); and Maximum Power, 7,200 pounds (32.027 kilonewtons) at 7,950 r.p.m. with water/alcohol injection (5 minute limit). The J47-GE-25 has a maximum diameter of 3 feet, 1 inch (0.940 meters) and length of 12 feet, 0 inches (3.658 meters) and weighs 2,653 pounds (1,203 kilograms)

The B-47E had a maximum speed of 497 knots (572 miles per hour/920 kilometers per hour) at 20,000 feet (6,096 meters), and 485 knots (558 miles per hour/898 kilometers per hour) at 38,600 feet (11,765 meters).

The service ceiling was 31,500 feet (9,601 meters) and combat ceiling 40,800 feet (12,436 meters).

The combat radius of the B-47E was 1,780 nautical miles 2,048 miles (3,297 kilometers with a 10,000 pound (4,536 kilograms) bomb load. Ferry range with 14,720 gallons (55,721 liters) of fuel was 4,095 nautical miles (4,712 miles/7,584 kilometers).

For defense the B-47E was armed with two M24A1 20 mm autocannons with 350 rounds of ammunition per gun. The remotely-operated tail turret was controlled by the co-pilot.

The maximum bomb load of the B-47E was 12,000 pounds (5,443 kilograms). The B-47 could carry up to six 2,000 pound (907 kilogram) bombs, or one 10,670 pound (4,840 kilograms) “Special Store”: a B-41 three-stage radiation-implosion thermonuclear bomb with a yield of 25 megatons).

B-47E-25-DT Stratojet 52-166 flies over California's Central Valley farmland as it heads to Castle Air Force Base on the very last B-47 flight, 17 June 1986. (U.S. Air Force)
B-47E-25-DT Stratojet 52-166 flies over California’s Central Valley farmland as it heads to Castle Air Force Base on the very last B-47 flight, 17 June 1986. (U.S. Air Force)

A total of 2,032 B-47s were built by a consortium of aircraft manufacturers: Boeing Airplane Company, Wichita, Kansas; Douglas Aircraft Company, Tulsa, Oklahoma; Lockheed Aircraft Company, Marietta, Georgia.

The Stratojet is one of the most influential aircraft designs of all time and its legacy can be seen in almost every jet airliner built since the 1950s: the swept wing with engines suspended below and ahead on pylons. The B-47 served the United States Air Force from 1951 to 1977. From the first flight of the Boeing XB-47 Stratojet prototype, 17 December 1947, to the final flight of B-47E 52-166, was 38 years, 6 months, 1 day.

B-47E-25-DT Stratojet 52-166 on final approach to land at Castle Air Force Base, 17 June 1986. The braking chute is deployed. This is teh very last time that a B-47 flew.
Douglas-built B-47E-25-DT Stratojet 52-166 on final approach to land at Castle Air Force Base, 17 June 1986. The approach chute is deployed. This was the very last time that a B-47 flew.

© 2018, Bryan R. Swopes

11 May 1964

Aviation, , , , , , , ,
XB-70A-1-NA 62-0001 rollout at Air Force Plant 42, 11 May 1964. (North American Aviation, Inc.)

11 May 1964: At Air Force Plant 42 near Palmdale, a small city in the high desert of southern California, the first prototype North American Aviation XB-70A-1-NA Valkyrie, 62-0001, was rolled out. More than 5,000 people were there to watch.

In August 1960, the U.S. Air Force had contracted for one XB-70 prototype and 11 pre-production YB-70 development aircraft. By 1964, however, the program had been scaled back to two XB-70As and one XB-70B. Only two were actually completed.

“Ride of the Valkyrs” by John Charles Dollman, 1909. In Norse mythology, the valkyries were immortal female figures who chose who among those who had died in battle were worthy of being taken to Valhalla.

The B-70 was designed as a Mach 3+ strategic bomber capable of flying higher than 70,000 feet (21,336 meters). Like its contemporaries, the Lockheed Blackbirds, the Valkerie was so advanced that it was beyond the state of the art. New materials and processes had to be developed, and new industrial machinery designed and built.

The XB-70A is a very large aircraft with a canard-delta configuration, built primarily of stainless steel and titanium. It has twin vertical fins combining the functions of stabilizers and rudders. The XB-70A Valkyrie prototype is 193 feet, 5 inches (58.953 meters) long, including the pitot boom, with a wingspan of 105 feet, 0 inches (32.004 meters) and overall height of 30 feet, 9 inches (9.373 meters). The canard span is 28 feet, 10 inches (8.788 meters). The canard has flaps, while the delta wing used multiple separate elevons for pitch and roll control.

North American Aviation XB-70A-1-NA Valkyrie takes off at Edwards Air Force Base, 17 August 1965. (NASA)

The delta wing has an angle of incidence of 0° and its leading edges are swept to 65.57°, with 0° sweep at the trailing edge. The wings have a maximum of -2.60° of twist. The wings of 62-001 have no dihedral, but the second B-70, 62-0207, had 5° dihedral. The total wing area is 6,297.8 square feet (585.1 square meters).

The canard also has 0° of incidence and dihedral. Its leading edge is swept aft 31.70°, while the trailing edge sweeps forward 14.91°. The canard has a total area of 415.59 square feet (38.61 square meters). The canard flaps can be lowered to 20°.

The vertical fins have a height of 15 feet (4.572 meters). The leading edges are swept 51.77° and the trailing edges, 10.89°.

The B-70 was designed to “surf” on its own supersonic shock wave (this was called “compression lift”). The outer 20 feet (6.096 meters) of each wing could be lowered to a 25° or 65° angle for high speed flight. Although this did provide additional directional stability, it actually helped increase the compression lift, which supported up to 35% of the airplane’s weight in flight.

North American Aviation XB-70A-1-NA Valkyrie 62-0001. (U.S. Air Force)

The first prototype, 62-001, had an empty weight of 231,215 pounds (104,877 kilograms), and its maximum takeoff weight was 521,056 pounds (236,347 kilograms).

The XB-70A is powered by six General Electric YJ93-GE-3 engines, grouped together in the tail. These are single-spool, axial-flow, afterburning turbojet engines, which have an 11-stage compressor section and 2-stage turbine. The YJ93-GE-3 has a normal power rating of 17,700 pounds of thrust (78.734 kilonewtons); military power, 19,900 pounds (88.520 kilonewtons); and maximum power, 28,000 pounds (124.550 kilonewtons). All ratings are at 6,825 r.p.m. and are continuous. A special high-temperature fuel, JP-6, is required. The engine is 19 feet, 8.3 inches (6.002 meters) long, 4 feet, 6.15 inches (1.375 meters) in diameter, and weighs 5,220 pounds (2,368 kilograms).

Test firing one the 62-001’s General Electric YJ93-GE-3 afterburning turbojet engines. (LIFE Magazine)

62-0001 had a cruise speed of 1,089 knots (1,253 miles per hour/2,016 kilometers per hour) at 35,000 feet (10,688 meters), and maximum speed of 1,721 knots (1,980 miles per hour/3,187 kilometers per hour) at 79,050 feet (24,094 meters)—Mach 2.97. During flight testing, the XB-70A reached a maximum of Mach 3.08 (1,777 knots) with a sustained altitude of 74,000 feet (22,555 meters).

Fuel was carried in 11 internal tanks in the wings and fuselage and the maximum capacity was 43,646 gallons (165,218 liters), giving the bomber a combat range of 3,786 nautical miles (4,357 statute miles/7,012 kilometers).

The B-70 was designed to carry two B-53 two-stage radiation-implosion thermonuclear bombs in its internal bomb bay. A maximum of fourteen smaller weapons could be carried.

XB-70A-1 62-0001 first flew 21 September 1964, and exceeded Mach 3 for the first time on its 17th flight, 14 October 1965. Its final flight was 4 February 1969.

The second prototype, XB-70A-2-NA 62-0207, was destroyed in a midair collision. The third Valkyrie, XB-70B-NA 62-0208, was cancelled before completion.

62-0001 is in the collection of the National Museum of the United States Air Force. It has made 83 flights with just 160 hours, 16 minutes, total flight time.

XB-70A-1-NA Valkyrie 62-0001 in cruise at very high altitude, 1968. (NASA)
XB-70A-1-NA Valkyrie 62-0001 in cruise at very high altitude, 1968. (NASA)

© 2019, Bryan R. Swopes