21 September 1964

North American Aviation XB70A-1-NA 62-001 takes off for the first time, 21 September 1964. (U.S. Air Force)
North American Aviation XB70A-1-NA 62-0001 takes off for the first time, 21 September 1964. (U.S. Air Force)

21 September 1964: The first prototype North American Aviation XB-70A-1-NA Valkyrie, serial number 62-0001, flown by Chief Test Pilot Alvin S. White and Colonel Joseph F. Cotton, U.S. Air Force, made its first flight from Air Force Plant 42, Palmdale, California, to Edwards Air Force Base.

Originally a prototype Mach 3 strategic bomber, 62-0001 (also known as AV-1) and it’s sister ship, XB-70A-2-NA, 62-0207, (AV-2), were built and used by the Air Force and NASA as high-speed research aircraft. The third Valkyrie, XB-70B-NA 62-0208 (AV-3), was never completed.

Major Joseph F. Cotton, USAF, and Alvin S. White, North American Aviation, with the XB-70A Valkyrie. (Autographed photograph courtesy of Neil Corbett, TEST & RESEARCH PILOTS, FLIGHT TEST ENGINEERS)
Colonel Joseph F. Cotton, USAF, and Alvin S. White, North American Aviation, with an XB-70A Valkyrie. (Autographed photograph courtesy of Neil Corbett, TEST & RESEARCH PILOTS, FLIGHT TEST ENGINEERS)

The B-70 was designed as a high-altitude Mach 3 strategic bomber armed with thermonuclear bombs. The XB-70A is 196 feet, 6 inches (59.893 meters) long with a wingspan of 105 feet (32.004 meters) and an overall height of 30 feet, 8 inches (9.347 meters). It weighs 231,215 pounds (104,877 kilograms) empty and has a maximum takeoff weight of 534,792 pounds (242,578 kilograms).

The XB-70’s delta wing had a total area of 6,297 square feet (585.01 square meters). it had a sweep of 58.0° at 25% chord. The angle of incidence was 0° and the wing incorporated 3.0° negative twist. There was no dihedral. (The second XB-70 had 5° dihedral.) The outer wing panels could be lowered as much as 60° to increase longitudinal stability in high speed flight.

The XB-70A was powered by six General Electric YJ93-GE-3 single-spool, axial-flow turbojet engines, which used an 11-stage compressor and two-stage turbine. The engine required a special heat-resistant JP-6 fuel. It had a maximum continuous power rating of 28,000 pounds of thrust (124.55 kilonewtons) at 6,825 r.p.m. The YJ93-GE-3 was 19 feet, 8.3 inches (6.002 meters) long, 4 feet, 6.15 inches (1.375 meters) in diameter, and weighed 5,220 pounds (2,368 kilograms).

A Boeing B-52 Stratofortress flies formation with North American Aviation XB-70A Valkyrie 62-0001, approaching the runway at Edwards Air Force Base, California. (U.S. Air Force)

The XB-70A had a maximum speed of Mach 3.1 (2,056 miles per hour, or 3,309 kilometers per hour). At 35,000 feet (10,668 meters), it could reach Mach 1.90 (1,254 miles per hour, or 2,018 kilometers per hour), and at its service ceiling of 75,550 feet (23,012 meters), it had a maximum speed of Mach 3.00 (1,982 miles per hour, or 3,190 kilometers per hour). The planned combat range for the production  bomber was 3,419 miles (5,502 kilometers) with a maximum range of 4,290 miles (6,904 kilometers).

North American Aviation XB-70A Valkyrie 62-0001 made 83 flights with a total of 160 hours, 16 minutes flight time. 62-0001 is on display at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio.

North American Aviation XB-70A Valkyrie 62-0001 lands at Edwards Air Force Base at the end of its first flight, 21 September 1964. (U.S. Air Force)
North American Aviation XB-70A-1-NA Valkyrie 62-0001 just before landing at Runway 4 Right, Edwards Air Force Base, ending of its first flight, 21 September 1964. A Piasecki HH-21B rescue helicopter hovers over the adjacent taxiway. (U.S. Air Force)

© 2018, Bryan R. Swopes

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21 September 1961

Vertol YCH-1B-BV 59-4983 hovers in ground effect. (Boeing Vertol)

21 September 1961: Boeing Vertol YCH-1B-BV, serial number 59-4983, a twin-turboshaft, tandem-rotor heavy lift helicopter, flown by test pilot Leonard Joseph (“Len”) LaVassar, made its first flight at Morton Grove, Pennsylvania. This aircraft was the number two prototype. (The first aircraft, 52-4982, had been damaged 12 July 1961 when the rotors went out of phase during ground testing. It was repaired but never flew.) In 1962, the YCH-1B was was redesignated YCH-47A.

The YCH-1B fuselage was 51 feet, 0 inches (15.545 meters) long and had a maximum width of 12 feet, 5 inches (3.785 meters). The helicopter’s overall length, with rotors turning, was 98 feet, 3.25 inches (29.953 meters), and its maximum height (to the tip of the uppermost blade) was 18 feet, 6.6 inches (5.654 meters). Empty weight of the production CH-47A is approximately 25,500 pounds.

The counter-rotating fully-articulated three-bladed rotors each had a diameter of 59 feet, 1.25 inches (18.015 meters). The forward rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right side.) The rear rotor turns the opposite direction. They rotate at 215 r.p.m.

Boeing Vertol YCH-1B-BV 59-04983

The prototypes were powered by two Lycoming LTC4B-3 (T55-L-5) turboshaft engines. These were free-turbine engines using a 7-stage axial-flow, 1-stage centrifugal-flow compressor section with a single-stage high-pressure turbine and two-stage low-pressure power turbine. The T55-L-5 was rated at 1,870 shaft horsepower at 14,430 r.p.m. N2. It was 3 feet, 8.1 inches (1.120 meters) long and weighed 560 pounds (254 kilograms).

The helicopter had a maximum speed of 153 knots (176 miles per hour/283 kilometers per hour) at Sea Level. Its hover ceiling, out of ground effect (HOGE), was 11,650 feet (3,551 meters), and in ground effect (HIGE), 14,500 feet (4,420 meters). The helicopter’s service ceiling was 18,600 feet (5,669 meters).

The Chinook prototypes were painted white and orange. This is the third YCH-1B, 59-4984. (Boeing Vertol)

The Chinook remains in production as the CH-47F Block II and MH-47G, and is used by the military services of several nations.

Boeing CH-47F Chinook. (Boeing)

© 2018, Bryan R. Swopes

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21 September 1942

A Boeing XB-29 takes off from Boeing Field, Seattle, Washington. (SDASM)
Edmund T. ("Eddie") Allen
Edmund T. (“Eddie”) Allen

21 September 1942: At Boeing Field, Seattle, Washington, the Boeing Model 345, the first of three XB-29 prototypes, Air Corps serial number 41-002, took off on its first flight.

Edmund T. “Eddie” Allen, Director of Aerodynamics and Flight Research, was in command, with Al Reed, Chief of Flight Test and Chief Test Pilot, as co-pilot. They climbed to 6,000 feet (1,829 meters) and began testing the XB-29’s stability and control, control power and response, and stall characteristics.

The flight was uneventful. Landing after 1 hour, 15 minutes, Allen is supposed to have said, “She flew!”

Eddie Allen lean’s out of a cockpit window following the first taxi test of the XB-29. (Boeing)

The XB-29 was 98 feet, 2 inches (29.921 meters) long with a wing span of 141 feet, 3 inches (43.053 meters), and 27 feet, 9 inches (8.458 meters) high to the top of its vertical fin. The prototype bomber had a gross weight of 105,000 pounds (47,627 kilograms).

Boeing XB-29-BO, 41-002, the first XB-29 built. (U.S. Air Force)
Boeing XB-29-BO, 41-002, the first of three prototypes. (U.S. Air Force)

The prototype bomber was powered by four air-cooled, supercharged and fuel-injected 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division Duplex-Cyclone 670C18H1 (R-3350-13) twin-row 18-cylinder radial engines with a compression ratio of 6.85:1. The R-3350-13 was rated at 2,000 horsepower at 2,400 r.p.m., and 2,200 horsepower at 2,800 r.p.m. for takeoff, burning 100-octane gasoline. These engines drove 17-foot-diameter (5.182 meters) three-bladed Hamilton Standard constant-speed propellers through a gear reduction of 0.35:1. The R-3350-13 was 76.26 inches (1.937 meters) long, 55.78 inches (1.417 meters) in diameter, and weighed 2,668 pounds (1,210 kilograms). Wright built 50 of these engines.

Boeing XB-29 41-002. (SDASM)

The XB-29 had a maximum speed of 368 miles per hour (592 kilometers per hour) and cruised at 255 miles per hour (410 kilometers per hour). Its service ceiling was 32,100 feet (9,784 meters).

The airplane was designed to carry 20,000 pounds (9,072 kilograms) of bombs. Though the prototypes were unarmed, the production B-29s were defended by 10 Browning AN-M2 .50-caliber machine guns in four remotely-operated power turrets, with 2 more .50-caliber machine guns and a single AN-M2 20mm autocannon in the tail.

Boeing XB-29 41-002. (SDASM)

The B-29 Superfortress was the most technologically advanced—and complex—aircraft of the War. It required the manufacturing capabilities of the entire nation to produce. Over 1,400,000 engineering man-hours had been required to design the prototypes.

The B-29 was manufactured by Boeing at Seattle and Renton, Washington, and at Wichita, Kansas; by the Glenn L. Martin Company at Omaha, Nebraska; and by Bell Aircraft Corporation, Marietta, Georgia. There were three XB-29 prototypes, 14 YB-29 pre-production test aircraft, 2,513 B-29, 1,119 B-29A, and 311 B-29B Superfortress aircraft. The bomber served during World War II and the Korean War and continued in active U.S. service until 1960.

The first prototype, 41-002, was scrapped in 1948.

Boeing B-29A-30-BN Superfortress 42-94106, circa 1945. (U.S. Air Force)
Boeing B-29A-30-BN Superfortress 42-94106, circa 1945. (U.S. Air Force)

© 2018, Bryan R. Swopes

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21 September 1937

Jackie Cochran sits in the cockpit of the Seversky SEV-S1, NR18Y, September 1937. Note how the landing gear retracts straight to the rear in this early version. It would be modified to retract inward to the airplane’s centerline, and more effectively streamlined in the future. (San Diego Air and Space Museum Archives)

21 September 1937: Jackie Cochran flew the Seversky Aircraft Corporation SEV-S1, civil registration NR18Y, over a 3 kilometer course at Detroit Wayne County Airport, Romulus, Michigan, averaging 470.40 kilometers per hour (292.29 miles per hour). This was a new Fédération Aéronautique Internationale (FAI) world speed record.¹

The Seversky SEV-S1 Executive was an improved version of the P-35 fighter, which was designed by Major Alexander P. de Seversky. The P-35 was the first U.S. Army Air Corps single-engine airplane to feature all-metal construction, an enclosed cockpit and retractable landing gear.

Seversky SEV-S1 NR18Y. (San Diego Air and Space Museum Archives)

The airplane had been built as the SEV-2XP, a two-place monoplane with fixed landing gear, and powered by an air-cooled, supercharged 1,666.860-cubic-inch-displacement (27.315 liter) Wright Aeronautical Division GR1670 two-row, 14-cylinder radial engine.

The SEV-2XP was to be a second entry, along with the SEV-1XP, to enter a fly-off against the Curtiss 75 Hawk for the Air Corps fighter contract in 1935. It was damaged, though, while en route Wright Field. The prototype was rebuilt as a single-place airplane with retractable landing gear and a 1,000-horsepower Wright Cyclone GR-1820G4 nine-cylinder engine. In this configuration, the airplane was designated SEV-1XP.

 The Seversky's passenger compartment was accessed through a hatch on the right side of the fuselage. (San Diego Air and Space Museum Archives) Jackie Cochran in the cockpit of the Seversky SEV-2S Executive, NR18Y. Note the passenger windows below and behind the cockpit. (San Diego Air and Space Museum Archives)
The Seversky’s passenger compartment was accessed through a hatch on the right side of the fuselage. (San Diego Air and Space Museum Archives)

After the Air Corps demonstrations, which resulted in an order for 100 Seversky P-35s, NX18Y was again repowered, this time with an air-cooled, supercharged, 1,829.39-cubic-inch-displacement (29.978 liter) Pratt & Whitney Twin Wasp S1B3-G (R-1830-11) two-row 14-cylinder radial engine. The R-1830-11 had a compression ratio of 6.7:1 and was rated at 850 horsepower at 2,450 r.p.m. at 5,000 feet (1,524 meters), and 1,000 horsepower at 2,600 r.p.m. for take off. 87-octane aviation gasoline was required. The engine turned a three-bladed Hamilton-Standard controllable-pitch propeller through a 3:2 gear reduction. The R-1830-11 was 4 feet, 8.66 inches (1.439 meters) long with a diameter of 4 feet, 0.00 inches (1.219 meters), and weighed 1,320 pounds (599 kilograms).

With the Twin Wasp, NR18Y’s designation was changed to SEV-S1. Frank Sinclair, Seversky’s chief test pilot, flew it in the 1937 Bendix Trophy Race and the Thompson Trophy Race. (Jackie Cochran flew a Beech Staggerwing in the ’37 Bendix, beating Sinclair and NX18Y by 33 minutes.) Sinclair went on to place fourth in the Thompson pylon race. The Seversky averaged 252.360 miles per hour (406.134 kilometers per hour).

Test pilot Frank Sinclair, Alexander de Seversky and Jackie Cochran with the Seversky SEV-2S, NR70R. (San Diego Air and Space Museum Archives)

¹ FAI Record File Number 12026

© 2018, Bryan R. Swopes

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20 September 1958

Avro Vulcan VX770.
The first of two prototypes, Avro Type 698 VX770. (BAE Systems)

20 September 1958: The first prototype Avro Vulcan strategic bomber, VX770, piloted by Rolls-Royce test pilot Keith Roland Sturt, was on a test flight from the Rolls-Royce Flight Test Establishment, RAF Hucknall, when it diverted to make a scheduled fly-past for an air show being held at RAF Syerston in Nottinghamshire. Also aboard were Co-Pilot Ronald W. Ward of Fairey Aviation; Rolls-Royce Flight Engineer William E. Howkins; and Navigator, Flight Lieutenant Raymond M. (“Polly”) Parrott, Royal Air Force.

VX770 approched RAF Syerstone at 12:57 p.m. (GMT) and flew east along Runway 07–25 at about 250 feet (76 meters). As the Vulcan passed the control tower at an estimated speed of 350 knots, it began a right turn.

Seen from below, VX770 shows the full delta wing of the prototype. Production aircraft used a modified wing with curved leading edges in order to delay compressibility effects at high speeds. (Unattributed)
Seen from below, VX770 shows the full delta wing of the prototypes. Production aircraft used a modified wing with curved leading edges in order to delay compressibility effects at high speeds. (Unattributed)

Witnesses saw a “kink” form in the leading edge of the Vulcan’s right wing, which then began to disintegrate from the leading edge aft. Wing surface panels could be seen being stripped off before the wing spar failed completely. Clouds of fuel from ruptured tanks trailed as the bomber rolled to the left. The top of the vertical fin came off, the nose pitched upward toward vertical, then straight down, and with both wings on fire, the airplane crashed near the east end of the runway.

All four crew members were killed, as were three RAF fire/rescue personnel on the ground. Several others were injured.

The right wing of Avro Vulcan VX770 disintegrates.
The right wing of Avro Vulcan VX770 disintegrates. (© Mary Evans/The National Archives, London, England)
Clouds of vaporized fuel trail the doomed bomber.
Clouds of vaporized fuel trail the doomed bomber. (Unattributed)
Vulcan VX770 crashed at the east end of Runway 07-25.
Vulcan VX770 crashed at the east end of Runway 07-25. Debris spread over 1,400 feet (427 meters). (MEV-10473694 © Mary Evans/The National Archives, London, England)

A short video clip of the fly-by and crash can be seen on You Tube:

The cause of the Vulcan’s wing failure was not determined. Metal fatigue was suspected. The airplane had been used in flight testing for six years and it is possible that it’s design limits may have been exceeded during that period. There was also speculation that vibrations from the new Rolls-Royce Conway “bypass turbojet” engine, which is now called a turbofan, may have weakened the wing.

According to the investigative report, Keith Sturt was considered to be an “above average” and “capable and careful” pilot. He had accumulated 1,644 hours of flight time over six years. He had flown VX770 for 91 hours, 40 minutes. Sturt was a former Flight Lieutenant of the Royal Air Force, having been inducted into the service in 1945.

VX770 was the first of two Type 698 prototypes built by A.V. Roe & Co., Ltd., at Woodford, Cheshire. It made its first flight 30 August 1951 with Chief Test Pilot R.J. “Roly” Falk. Originally equipped with Rolls-Royce Avon R.A.3 turbojet engines, these were soon replaced with more powerful Armstrong Siddely Sapphire A.S.Sa.6 engines. During modification in 1953, fuel cells were added to the wings. As production airplanes were built with Bristol Olympus Mk.102 engines, VX770 was modified accordingly. During its final flight, it was powered by Rolls-Royce Conway RCo.10 turbofans.

Keith Roland Sturt was born in Guildford, Surrey, England, 20 April 1929, the son of George Sturt and Daisy May Raveney Sturt. On 20 June 1957, Sturt married Mrs. Colin Weal Coulthard (née Norah Ellen Creighton) in Surrey.

© 2018, Bryan R. Swopes

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