Daily Archives: September 21, 2023

21 September 1967

Lockheed AH-56 Cheyenne 66-8827 hovering at Van Nuys Airport, 21 September 1967. (Lockheed)

21 September 1967: The Lockheed AH-56A Cheyenne made its first flight at Van Nuys Airport (VNY), Van Nuys, California. In the cockpit was Lockheed test pilot (and former lieutenant colonel, USMC) Donald Riley Segner, Lieutenant Colonel Emil Eldon (“Jack”) Kluever, U.S. Army, the Army’s project officer.

The Lockheed AH-56A Cheyenne was a prototype armed helicopter. It was a two-place, single-engine, compound helicopter, developed by the Lockheed-California Company for the United States Army. Ten prototypes were built at Lockheed’s plant B-9 at Van Nuys Airport. It had a four-bladed rigid main rotor, a stub wing, a four-bladed tail rotor and a three-bladed pusher propeller. The two-place cockpit is tandem, with the pilot-in-command flying from the rear seat. A co-pilot/gunner is seated forward.

The Cheyenne is 54 feet, 8 inches (16.662 meters) long, and 13 feet, 8.5 inches (4.178 meters) high. The main rotor has a diameter of 51 feet, 3 inches (15.621 meters). Its stub wing had a span of The prototype empty weight is 12,215 pounds (5,540.6 kilograms), and maximum takeoff weight is 25,880 pounds (11,739 kilograms).

Donald R. Segner with prototype Lockheed YAH-56A-LO Cheyenne prototype 56-8831, missile and night vision test vehicle. (Lockheed)

The Cheyenne is powered by a single General Electric T64-GE-16A engine, rated at 3,485 shaft horsepower (2,599 kiloWatts). The T64 is an axial flow free-turbine turboshaft engine. It has a 14-stage compressor and 4-stage turbine (2 high-pressure and 2 low pressure). The turbine shaft is coaxial with the compressor shaft and delivers power forward. The engine is 6 feet, 7.0 inches (2.007 meters) long, 2 feet, 0.2 inches (0.615 meters) in diameter, and weighs 720 pounds (327 kilograms). This engine was also used in the Sikorsky CH-53A.

The Cheyenne had a cruise speed of 195 knots (224 miles per hour/361 kilometers per hour), and maximum speed of 212 knots (244 miles per hour/393 kilometers per hour). It could climb at 3,000 feet per minute (15.24 meters per second) and had a service ceiling of 21,000 feet (6,401 meters). The helicopter’s range was 1,063 nautical miles (1,223 statute miles/1,969 kilometers).

One of the ten Lockheed AH-56A Cheyenne compound helicopters firing unguided Mk 4 FFARs. (U.S. Army)

The AH-56A could be armed with a 7.62 mm XM196  six-barrel rotary machine gun (“minigun”), or a 40 mm M129 grenade launcher mounted in a turret at the nose. It had six hard points under the stub wings that could carry 2.75-inch (70 mm) Mk 4 Folding-Fin Aerial Rocket pods or BGM-71 Tube-launched, Optically-tracked, Wire-guided (“TOW”) anti-tank missiles.

Lockheed built ten AH-56A Cheyenne helicopters. The third prototype, 66-8828, was destroyed during a test flight, 12 March 1969, when the main rotor struck the fuselage. The test pilot was killed. The tenth prototype, 66-8835, was seriously damaged while being tested in the NASA Ames full-scale wind tunnel, 17 September 1969. Like 66-8828, its main rotor struck the fuselage.

The Cheyenne program was cancelled 9 August 1972.

Lockheed AH-56A Cheyenne 66-8827 is on display at the Fort Polk Military Museum, Fort Polk, Louisiana.

© 2023, Bryan R. Swopes

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

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 I and MH-47G, and is used by the military services of several nations. Boeing is continuing development of the Block II variant.

Boeing CH-47F Chinook. (Boeing)

© 2023, Bryan R. Swopes

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

21 September 1937

Jackie Cochran sits in the cockpit of the Seversky SEV-1XP, R18Y, circa September 1937. (San Diego Air & Space Museum Archives)

21 September 1937: Jackie Cochran flew the Seversky Aircraft Corporation SEV-1XP, registered R18Y, over a 3 kilometer (1.864 statute miles) course at Detroit Wayne County Airport, Romulus, Michigan. The average speed for six passes was 470.40 kilometers per hour (292.29 miles per hour). This was a new Fédération Aéronautique Internationale (FAI) world speed record.¹

The Lansing, Michigan, State Journal reported:

New York Aviatrix Smashes the Feminine World’s Speed Record at Detroit


Jacqueline Cochran Averages Speed of 293.05 M.P.H. In 3-Kilometer Flight

     DETROIT, Sept. 21 (AP)—Jacqueline Cochran, New York aviatrix, averaged 293.05 miles an hour in four flights over a three-kilometer course Tuesday, bettering the women’s land plane speed record of 276.527 miles an hour established in 1934 by the late Helene Boucher of France.

     Miss Cochran made six flights, three east and three west, over the course, but only four of the flights were included in the official computation. She was timed at 304.62 miles an hour in her fastest dash, an eastward flight. Her speed on the slowest flight was 282.06 miles an hour.

     All of the flights were at altitudes of between 100 and 150 feet, thus complying with a National Aeronautics association [sic] rule that flights for records must be made below 250 feet.

     Miss Cochran flew a Seversky military pursuit demonstrator, with a 1,200 horsepower engine. The plane is of a type similar to a fleet soon to be put in use at Selfridge field, Mt. Clemens, Mich.

     “Ever since I started flying, five years ago, I’ve dreamed of doing this,” Miss Cochran said when she was notified of her record speed.

     Her record attempt, made at the Wayne county airport, was postponed four times by adverse winds. She had perfect weather conditions Tuesday.

     Airport officials said Miss Cochran’s flights were the fastest ever flown at the airport, by either a man or a woman.

The State Journal, Vol. 83, Tuesday, 21 September 1937, Page 8, Column 1

For this and her other accomplishments, Ms. Cochran was awarded the Harmon International Aviatrix Trophy by Mrs. Franklin D. Roosevelt in a ceremony in New York City, 4 April 1938.

Jackie Cochran is presented the Harmon International Aviatrix Trophy by Mrs. Franklin D. Roosevelt. (Acme)

The Seversky SEV-1XP (also called the “SEV-S1 Executive”) was the original prototype for a fly-off against the Curtiss-Wright Model 75 Hawk and Northrop 3A improved version of the P-35 fighter, which was designed by Alexander Kartveli. 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.

The airplane had originally been built as a single-place, open cockpit monoplane with fixed landing gear. It was designated the Seversky II X, s/n 2, and given the experimental registration mark X18Y. In order to compete for the Army Air Corps pursuit contract of 1935, X18Y was modified into a two-place fighter with an enclosed canopy. It was armed with two machine guns mounted in the engine cowling, while a gunner sat behind the pilot with a third machine gun on a flexible mount. Still officially the Seversky II X, the company called it the SEV-2XP.

The Seversky SEV-2XP X18Y in the two-place, fixed landing gear configuration. (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog #: 16_006753)

In this configuration, X18Y was powered by an experimental air-cooled, supercharged, Wright Aeronautical Division GR1670A1 Whirlwind. This was a two-row, 14-cylinder radial engine with a displacement of 1,666.860 cubic inches (27.315 liters). It had a compression ratio of 6.75:1 and required 87-octane gasoline. The GR1670A1 had a normal power rating of 775 horsepower at 2,400 r.p.m., and 830 horsepower at 2,400 r.p.m. for takeoff. It drove an experimental three-bladed Hamilton Standard constant-speed propeller through a 16:11 gear reduction. The GR1670A1 was 45 inches (1.143 meters) in diameter, 52-25/32 inches (1.341 meters) long, and weighed 1,160 pounds (526 kilograms).

In mid-May 1935, Major de Seversky flew the prototype from the factory at Farmingdale, New York, toward Wright Field, Dayton, Ohio. The engine overheated, then seized, and Seversky made a forced landing on a small hilltop airfield near St. Clairsville, Ohio. X18Y suffered slight damage. A local pilot flew Seversky on to the meeting at Wright. Once there, he saw the Curtiss-Wright and Northrop competition, both single-place pursuits with retractable landing gear. The SEV-2XP was outclassed.

After repairs, on 20 June Seversky flew X18Y out of the small field and returned it to Farmingdale. It was extensively reconfigured as a single-place airplane. A new wing with retractable landing gear was installed, as were new tail surfaces. A Wright Cyclone R-1820G4 9-cylinder radial engine replaced the experimental GR1670A1. The G4 had a normal power rating of 810 horsepower at 2,100 r.p.m., and 1,000 horsepower at 2,200 r.p.m., using 87-octane gasoline. Seversky redesignated X18Y as the SEV-1XP. After a fly off with the modified prototype, the Air Corps placed an order for 100 Seversky P-35s.

Major Alexander de Seversky with SEV-1XP X18Y. (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog )

Seversky continued to experiment with new engines, installing a GR-1820G5. In January 1937, a change was made to the Pratt & Whitney Twin Wasp R-1830-13, the same engine being installed in production Curtiss-Wright P-36 Hawks. This was a two-row, supercharged 14-cylinder radial engine with a normal power rating of 900 horsepower at 2,550 r.p.m. to an altitude of 10,000 feet (3,048 meters), and 1,050 horsepower at 2,700 r.p.m. for takeoff. The airplane retained the same three-bladed constant-speed Hamilton Standard propeller which had been used with the Wright Cyclone engine. It was driven through a 3:2 gear reduction.

X18Y was reconfigured as a two-place civilian transport, with a small passenger cabin below and behind the cockpit. There were two fixed windows on the left side of the fuselage, and the passenger entered through a hatch on the right side, over the wing. A Pratt & Whitney Twin Wasp SB-G was fitted. This engine was very slight smaller and weighed less than the R-1830-13, and had a normal rating of 900 horsepower at 2,450 r.p.m. to 6,500 feet (1,981 meters), and 1,000 horsepower at 2,600 r.p.m. for takeoff.

The Seversky’s passenger compartment was accessed through a hatch on the right side of the fuselage. (San Diego Air and Space Museum Archives)

In this new configuration the SEV-1XP was called the “SEV-S1 Executive.” The experimental registration was changed to restricted: R18Y.

On 4 September 1937, R18Y was flown by Seversky’s chief test pilot, Frank Sinclair, in the cross-country Bendix Trophy Race. It carried the race number 63 on the vertical fin. Sinclair finished in fourth place, 33 minutes behind Jackie Cochran in her green Beechcraft D17W Staggerwing. He then flew R18Y in the Thompson Trophy pylon race, again finishing fourth with an average of 252.360 miles per hour (406.134 kilometers per hour).

On 27 October the SEV-1XP reverted to its experimental license number, X18Y.

Ms. Cochran continued to fly the Seversky in speed record attempts. On 3 December she flew it from Floyd Bennett Field in New York to Miami, Florida, in an elapsed time of 4:12:27.2, averaging 278.13 miles per hour (447.61 kilometers per hour).

Jackie Cochran with the Seversky “SEV-S1 Executive,” X18Y, 1937. (Cliff Henderson Collection, San Diego Air & Space Museum Archives, Catalog #: CF_09-0043)

On 9 December Jackie flew X18Y to a new U.S. national record speed of 252.875 miles per hour (406.963 kilometers per hour) over a 100-kilometer course. She was attempting to increase the her speed on 13 December, reaching an average 255.973 miles per hour (411.949 kilometers per hour).

When she landed at Miami after the record runs, the Seversky’s tail wheel began rapidly swinging from side to side. This was something that the P-35s were experiencing and a number of the fighters had been wrecked. Jackie said, “One wing was pulled off altogether and the landing gear was torn off,” she said. “The tail [wheel] had jumped its lock throwing the plane to one side.”

The SEV-1XP was damaged beyond economical repair. In less than three years it had served its purpose. Seversky would build a new airplane. X18Y’s registration was suspended 4 January 1938 and the airplane was scrapped.

Seversky SEV-1XP X18Y after a landing accident, Miami, Florida, 13 December 1937. (Los Angeles Times, Vol. LVII, Tuesday, 14 December 1937, Page 20)

¹ FAI Record File Number 12026

© 2020, Bryan R. Swopes