21 August 1967: On the 186th flight of the X-15 program, the modified North American Aviation X-15A-2, 56-6671, made the first of two flights with a heat-protective ablative coating, designed to protect the steel structure of the rocketplane from the extreme heat of flight at high Mach numbers.
After a landing accident which caused significant damage to the Number 2 X-15, it was rebuilt by North American. A 28-inch (0.71 meter) “plug” was installed in the fuselage forward of the wings to create space for a liquid hydrogen fuel tank which would be used for an experimental “scramjet” engine that would be mounted the the ventral fin. The modified aircraft was also able to carry two external fuel tanks. It was hoped that additional propellant would allow the X-15A-2 to reach much higher speeds. The external tanks were not carried on the 21 August 1967 flight.
With Major William J. (“Pete”) Knight, U.S. Air Force, in the cockpit, the X-15A-2 was airdropped from the Boeing NB-52B Stratofortress, 52-008, known as Balls 8, over Hidden Hills Dry Lake, just on the California side of the border with Nevada. This was Knight’s 11th X-15 flight, and the 52nd flight for 56-6671. The launch time was 10:59:16.0 a.m., PDT. Knight fired the 57,000-pound-thrust Reaction Motors XLR99-RM-1 rocket engine and accelerated for 82.2 seconds. The purpose of this flight was to attain a high speed rather than altitude. The X-15A-2 reached Mach 4.94 (3,368 miles per hour, 5,420 kilometers per hour) at 85,000 feet (25,908 meters) and reached a peak altitude of 91,000 feet (27,737 meters). Pete Knight touched down on Rogers Dry Lake at Edwards Air Force Base, just 7 minutes, 40.0 seconds after launch.
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.
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 sisterships 52-002 and 52-003. It was scrapped at Tinker Air Force Base in 1961.
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.
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 feet, 6.9 inches (47.724 meters) long with a wingspan of 185 feet, 0 inches (56.388 meters) and overall height of 48 feet, 3.6 inches (14.722 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 35°. The bomber’s empty weight was 164,081 pounds (74,226 kilograms), with a combat weight of 272,000 pounds (123,377 kilograms) and a maximum takeoff weight of 420,000 pounds (190,509 kilograms).
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). These engines were rated at 10,500 pounds of thrust (46.71 kilonewtons), each, or 12,100 pounds (53.82 kilonewtons) with water injection.
The B-52B/RB-52B had a cruise speed of 523 miles per hour (842 kilometers per hour). The maximum speed varied with altitude: 630 miles per hour (1,014 kilometers per hour) at 19,800 feet (6,035 meters), 598 miles per hour (962 kilometers per hour) at 35,000 feet (10,668 meters) and 571 miles per hour (919 kilometers per hour) at 45,750 feet (13,945 meters). The service ceiling at combat weight was 47,300 feet (14,417 meters).
Maximum ferry range was 7,343 miles (11,817 kilometers). With a 10,000 pound (4,536 kilogram) bomb load, the B-52B had a combat radius of 3,590 miles (5,778 kilometers). With inflight refueling, the range was essentially world-wide.
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. 52-013 was one of eighteen RB-52Bs equipped with two M24A1 20 mm autocannon in the tail turret in place of the standard four .50-caliber M3 machine guns.
The B-52B’s maximum bomb load was 43,000 pounds (19,505 kilograms). It could carry a 15-megaton Mark 17 thermonuclear bomb, or two Mark 15s, each with a maximum yield of 3.8 megatons.
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.
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.
19 May 1976: A Strategic Air Command Boeing B-52D Stratofortress eight-engine bomber took off from Carswell Air Force Base, Fort Worth, Texas on a training flight. As the airplane’s landing gear was retracting, the hydraulic system failed leaving the right front gear with its 2-wheel bogie partially retracted and unlocked. The hydraulic system failure also disabled the B-52’s steering, brakes and rudder. Captain James A. Yule, an Instructor Pilot, took command of the aircraft. SAC headquarters at Omaha, Nebraska, diverted the airplane to Edwards Air Force Base in California so that the bomber could land on the large dry lake bed there.
After a five-hour flight and making several practice approaches, Captain Yule landed the aircraft. With no brakes, it coasted for two-and-a-half miles before coming to a stop. During the roll out, the right front bogie bounced up and down, providing no support. However, with the limited control available, Captain Yule successfully landed the Stratofortress with no damage and no injuries to the crew. He and another pilot received the Air Medal, and the rest of the air crew were awarded the Air Force Commendation Medal.
Captain Yule was the recipient of the Mackay Trophy for 1976. Established in 1911 and administered by the National Aeronautic Association, the Mackay Trophy is awarded to the “most meritorious flight of the year” by an Air Force person, persons, or organization. His citation reads:
“For gallantry and unusual presence of mind while participating in a flight as an instructor pilot of a B-52D Stratofortress.
“Captain James A Yule, distinguished himself by gallantry and unusual presence of mind while participating in an aerial flight as an instructor pilot of a B-52D aircraft on 19 May 1976. Captain Yule’s flight developed a unique multiple emergency and he assumed command of the aircraft, and at great personal risk, checked out the hydraulic open wheel well area to detect the problem. Using initiative, he coordinated with ground agencies and crew members and determined that a safe landing could be made after loss of braking and complete failure of steering. Captain Yule’s professional competence and outstanding airmanship under extreme stress resulted in successful recovery of the crew and a valuable aircraft. His courageous acts in landing a malfunctioning aircraft reflect great credit upon himself and the United States Air Force.”