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.”
10 March 1959: With North American Aviation’s Chief Engineering Test Pilot Albert Scott Crossfield in its cockpit, the X-15 high speed research rocket plane was airborne for the first time. X-15A 56-6670 was carried aloft under the wing of the Boeing NB-52A Stratofortress mother ship, 52-003, for a series of captive flights. The purpose was to verify that all the systems on both the X-15 and the mothership were properly functioning up to the point that the drop would occur.
Fully settled in my tiny flight office, I could speak by radio to the B-52 pilot, Charlie Bock, who was about thirty feet away in the nose of the mother plane, out of sight. . . .
As we sat, waiting at the end of the long runway while chase planes took off and circled, the clock on the instrument panel of the X-15 showed 0955. . . On signal, B-52 pilot Charlie Bock cobbed the eight engines, standing hard on the brake pedal. As the engines wound up to full military power, the X-15 trembled and the noise was tremendous. Through my radio earphones I heard Bock call a countdown for the benefit of the official movie cameramen who would record every inch of the takeoff:
“Five . . . four . . . three . . . two . . . one. BRAKE RELEASE.”
One hundred thirty tons of aluminum, fuel, Inconel X, five men and the hope of a nation began rolling down the long runway. . .
As we rolled, the huge runway distance markers flashed by, clocking our path: 14,000 . . . 13,000 . . . 12,000 . . . 8,000. When the X-15 air-speed indicator reached 170 knots, I noted only a minor vibration. We would continue the takeoff. 6,000 . . . 5,000 . . . 4,000, and we broke ground. It was smooth and gentle, like the take-off of an airliner. The air-speed indicator crept up to 260 knots. The parched brown desert fell away. . . .
—Always Another Dawn: The Story of a Rocket Test Pilot, by A. Scott Crossfield and Clay Blair, Jr., The World Publishing Company, Cleveland and New York, 1960, Chapters 34 and 35 at Pages 316–321.
The gross weight of the combined aircraft was 258,000 pounds (117,000 kilograms). After a takeoff roll of 6,200 feet (1,890 meters) the B-52/X-15 lifted of at 168 knots (193 miles per hour/311 kilometers per hour). During the 1 hour, 8 minute flight the the B-52 climbed to 45,000 feet (13,716 meters) and reached a speed of 0.83 Mach (548 miles per hour/881 kilometers per hour).
The X-15A rocketplane was designed and built for the U.S. Air Force and the National Advisory Committee for Aeronautics (NACA, the predecessor of NASA) by North American Aviation, Inc., to investigate the effects of hypersonic flight (Mach 5+). Design work started in 1955 and a mock-up had been completed after just 12 months. The three X-15s were built at North American’s Los Angeles Division, at the southeast corner of Los Angeles International Airport (LAX), on the shoreline of southern California.
The first flight took place 8 June 1959, again, with Scott Crossfield in the cockpit of the Number 1 ship, 56-6670.
While earlier rocketplanes, the Bell X-1 series, the the Douglas D-558-II, and the Bell X-2, were airplanes powered by rocket engines, the X-15 was a quantum leap in technology. It was a spacecraft.
Like the other rocketplanes, the X-15 was designed to be carried aloft by a “mothership,” rather than to takeoff and climb to the test altitude under its own power. The carrier aircraft was originally to be a Convair B-36 intercontinental bomber but this was soon changed to a Boeing B-52 Stratofortress. Two B-52s were modified to carry the X-15: NB-52A 52-003, The High and Mighty One, and NB-52B 52-008, Balls 8.
From 8 June 1959 to 24 October 1968, the three X-15s were flown by twelve test pilots, three of whom would qualify as astronauts in the X-15. Two would go on to the Apollo Program, and one, Neil Alden Armstrong, would be the first human to set foot on the surface of the Moon, 20 July 1969. Joe Engle would fly the space shuttle. Four of the test pilots, Petersen, White, Rushworth, and Knight, flew in combat during the Vietnam War, with Bob White being awarded the Air Force Cross. Petersen, Rushworth and White reached flag rank.
One pilot, John B. (“Jack”) McKay, was seriously injured during an emergency landing at Mud Lake, Nevada, 9 November 1962. Michael James Adams, was killed when the Number 3 ship, 56-6672, went into a hypersonic spin and broke up on the program’s 191st flight, 15 November 1967.
Flown by a single pilot/astronaut, the X-15 is a mid-wing monoplane with dorsal and ventral fin/rudders and stabilators. The wing had no dihdral, while the stabilators had a pronounced -15° anhedral. The short wings have an area of 200 square feet (18.58 square meters) and a maximum thickness of just 5%. The leading edges are swept to 25.64°. There are two small flaps but no ailerons. The entire vertical fin/rudder pivots for yaw control.
Above 100,000 feet (30,840 meters) altitude, conventional aircraft flight control surfaces are ineffective. The X-15 is equipped with a system of reaction control jets for pitch, roll and yaw control. Hydrogen peroxide was passed through a catalyst to produce steam, which supplied the control thrusters.
The forward landing gear consists of a retractable oleo strut with steerable dual wheels and there are two strut/skids at the rear of the fuselage. The gear is retracted after the X-15 is mounted on the NB-52 and is extended for landing by its own weight.
The rocketplane’s cockpit featured both a conventional control stick as well as side-controllers. It was pressurized with nitrogen gas to prevent fires. The pilot wore an MC-2 full-pressure suit manufactured by the David Clark Company of Worcester, Massachusetts, with an MA-3 helmet. The suit was pressurized below the neck seal with nitrogen, while the helmet was supplied with 100% oxygen. This pressure suit was later changed to the Air Force-standardized A/P22S.
The X-15 is 50.75 feet (15.469 meters) long with a wing span of 22.36 feet (6.815 meters). The height—the distance between the tips of the dorsal and ventral fins—is 13.5 feet (4.115 meters). The stabilator span is 18.08 feet (5.511 meters). The fuselage is 4.67 feet (1.423 meters) deep and has a maximum width of 7.33 feet (2.234 meters).
Since the X-15 was built of steel rather than light-weight aluminum, as are most aircraft, it is a heavy machine, weighing approximately 14,600 pounds (6,623 kilograms) empty and 34,000 pounds (15,422 kilograms) when loaded with a pilot and propellants. The X-15s carried as much as 1,300 pounds (590 kilograms) of research instrumentation, and the equipment varied from flight to flight. The minimum flight weight (for high-speed missions): 31,292 pounds (14,194 kilograms) The maximum weight was 52,117 pounds (23,640 kilograms) at drop (modified X-15A-2 with external propellant tanks).
Initial flights were flown with a 5 foot, 11 inch (1.803 meters)-long air data boom at the nose, but this would later be replaced by the “ball nose” air sensor system. The data boom contained a standard pitot-static system along with angle-of-attack and sideslip vanes. The boom and ball nose were interchangeable.
The X-15s were built primarily of a nickel/chromium/iron alloy named Inconel X, along with corrosion-resistant steel, titanium and aluminum. Inconel X is both very hard and also able to maintain its strength at the very high temperatures the X-15s were subjected to by aerodynamic heating. It was extremely difficult to machine and special fabrication techniques had to be developed.
Delays in the production of the planned Reaction Motors XLR99 rocket engine forced engineers to adapt two vertically-stacked Reaction Motors XLR11-RM-5 four-chamber rocket engines to the X-15 for early flights. This was a well-known engine which was used on the previous rocketplanes. The XLR-11 burned a mixture of ethyl alcohol and water with liquid oxygen. Each of the engines’ chambers could be ignited individually. Each engine was rated at 11,800 pounds of thrust (58.49 kilonewtons) at Sea Level.
The Reaction Motors XLR99-RM-1 rocket engine was throttleable by the pilot from 28,500 to 60,000 pounds of thrust. The engine was rated at 50,000 pounds of thrust (222.41 kilonewtons) at Sea Level; 57,000 pounds (253.55 kilonewtons) at 45,000 feet (13,716 meters), the typical drop altitude; and 57,850 pounds (257.33 kilonewtons) of thrust at 100,000 feet (30,480 meters). Individual engines varied slightly. A few produced as much as 61,000 pounds of thrust (271.34 kilonewtons).
The XLR99 burned anhydrous ammonia and liquid oxygen. The flame temperature was approximately 5,000 °F. (2,760 °C.) The engine was cooled with circulating liquid oxygen. To protect the exhaust nozzle, it was flame-sprayed with ceramic coating of zirconium dioxide. The engine is 6 feet, 10 inches (2.083 meters) long and 3 feet, 3.3 inches (0.998 meters) in diameter. It weighs 910 pounds (413 kilograms). The Time Between Overhauls (TBO) is 1 hour of operation, or 100 starts.
The XLR99 proved to be very reliable. 169 X-15 flights were made using the XLR99. 165 of these had successful engine operation. It started on the first attempt 159 times.
The highest speed achieved during the program was with the modified number two ship, X-15A-2 56-6671, flown by Pete Knight to Mach 6.70 (6,620 feet per second/4,520 miles per hour/ kilometers per hour) at 102,700 feet (31,303 meters). On this flight, the rocketplane exceeded its maximum design speed of 6,600 feet per second (2,012 meters per second).
The maximum altitude was reached by Joe Walker, 22 August 1963, when he flew 56-6672 to 354,200 feet (107,960 meters).
The longest flight was flown by Neil Armstrong, 20 April 1962, with a duration of 12 minutes, 28.7 seconds.
North American Aviation X-15A-1 56-6670 is on display at the Smithsonian Institution National Air and Space Museum. X-15A-2 56-6671 is at the National Museum of the United States Air Force.
20 February 1966: Brigadier General James M. Stewart, United States Air Force Reserve, flew the last combat mission of his military career, a 12 hour, 50 minute “Arc Light” bombing mission over Vietnam, aboard Boeing B-52 Stratofortress of the 736th Bombardment Squadron, 454th Bombardment Wing. His bomber was a B-52F-65-BW, serial number 57-149, call sign GREEN TWO. It was the number two aircraft in a 30-airplane bomber stream. The aircraft commander was Captain Bob Amos, and co-pilot, Captain Lee Meyers. Other crew members were Captain Irby Terrell, radar navigator, Captain Kenny Rahn, navigator, and technical Sergeant Demp Johnson, gunner.
Jimmy Stewart was a successful Hollywood actor. He had an interest in aviation since childhood, and he earned a private pilot license in 1935, then upgraded to a commercial license in 1938. He owned his own airplane, a Stinson 105, and frequently flew it across the country to visit his family.
Stewart enlisted as a private in the United States Army 22 March 1941, just three weeks after winning the Academy Award for Best Actor for his performance in “The Philadelphia Story.”
Because of his college education and experience as a pilot, Corporal James M. Stewart was commissioned as a second lieutenant in the Army Air Corps on 19 January 1942. He was assigned as an instructor pilot at Mather Field, California. Stewart was next assigned as a pilot at the Bombardier School at Kirtland AAF, Albuquerque, New Mexico. After transition training in the B-17 Flying Fortress he was assigned as as an instructor at Gowen Field, Boise, Idaho. On 9 July 1943, Stewart was promoted to captain and given command of a training squadron.
Concerned that his celebrity status would keep him in “safe” assignments, Jimmy Stewart had repeatedly requested a combat assignment. His request was finally approved and he was assigned as operations officer of the 703rd Bombardment Squadron, 445th Bombardment Group, a B-24 Liberator unit soon to be sent to the war in Europe. Three weeks later, he was promoted to commanding officer of the 703rd.
The 445th Bombardment Group arrived in England and after initial operational training, was stationed at RAF Tibenham, Norfolk, England. The unit flew its first combat mission on 13 December 1943, with Captain Stewart leading the high squadron of the group formation in an attack against enemy submarine pens at Kiel, Germany. On his second mission, Jimmy Stewart led the entire 445th Group.
On 7 January 1944, Stewart was promoted to major, and served as deputy commander of the 2nd Bombardment Wing during a series of missions known as “Big Week.” He was awarded the Distinguished Flying Cross.
Major Stewart was next assigned as Group Operations Officer of the 453rd Bombardment Wing at RAF Old Buckenham. He assigned himself to fly the lead B-24 in the group’s missions against Germany until he was promoted to Lieutenant Colonel and assigned as executive officer of the 2nd Bombardment Wing. In this position he flew missions with the 445th, 453rd, 389th Bomb Groups, and with units of the 20th Combat Bomb Wing. After being promoted to the rank of Colonel on 29 March 1945, he was given command of the 2nd Bombardment Wing. He had risen from Private to Colonel in four years. He received a second Distinguished Flying Cross and was presented the Croix de Guerre avec Palme by France.
Following World War II, Jimmy Stewart remained in the U.S. Air Corps as a Reserve Officer, and with the United States Air Force after it became a separate service in 1947. He commanded Dobbins Air Reserve Base, Marietta, Georgia. In 1953, his rank of colonel was made permanent, and in 1959, Jimmy Stewart was promoted to Brigadier General. During his active duty periods, Colonel Stewart remained current as a pilot of Convair B-36 Peacemaker, Boeing B-47 Stratojet and B-52 Stratofortress intercontinental bombers of the Strategic Air Command.
James Stewart was one of America’s most successful film actors. He made a number of aviation films , such as “No Highway in the Sky,” “Strategic Air Command,” “The Spirit of St. Louis”and “The Flight of the Phoenix.”
Brigadier General James Maitland Stewart retired from the U.S. Air Force in 1968. He died of a heart attack 2 July 1997 at the age of 89 years.
18 December 1972: On the first night of Operation Linebacker II, Staff Sergeant Samuel O. Turner, U.S. Air Force, the gunner aboard Boeing B-52D-35-BW Stratofortress 56-676 (call sign “Brown 3”), saw a supersonic MiG-21 interceptor approaching the bomber from below and behind with a second following at a distance.
As the Mach 2 fighter made a firing pass, Turner directed the four AN/M3 .50-caliber machine guns of the bomber’s tail turret at the enemy fighter and opened fire. In a single 6-second burst, he expended approximately 700 rounds of ammunition. He saw “a gigantic explosion to the rear of the aircraft.”
SSGT Turner is the first B-52 gunner to be officially credited with shooting down an enemy fighter and he was awarded the Silver Star.
The citation reads, in part, “By his courage in the face of hazardous combat conditions and outstanding professional skill, he successfully defended his aircraft and its crew and enabled it to complete its mission and return safely to base. . . .”
Senior Master Sergeant Samuel O. Turner died 11 May 2004.
B-52D 56-676 is on display at Fairchild Air Force Base, Spokane, Washington.
29 September 1965: Ten years after it entered service, the first operational Boeing B-52 Stratofortress, RB-52B-15-BO 52-8711, was retired to the Strategic Aerospace Museum, Offutt Air Force Base, Nebraska.
52-8711 had arrived at Castle Air Force Base, California, 29 June 1955, and was assigned to the 93rd Bombardment Wing (Heavy). It later served with the 22nd Bombardment Wing (Heavy) at March Air Force Base, California.