Tag Archives: Lockheed AH-56A Cheyenne

12 March 1969

Aviation, , , ,
Lockheed AH-56A Cheyenne (Lockheed Martin)

12 March 1969: At 11:56 a.m., a prototype Lockheed AH-56 Cheyenne compound helicopter, serial number 66-8828 (manufacturer’s serial number 1003), was destroyed during a test flight off the coast of Southern California. The test pilot, David A. Beil, was killed.

The Los Angeles Times reported:

Pilot Killed in Crash of Experimental Helicopter

CARPINTERIA — An experimental helicopter under test for the Army caught fire, exploded and crashed in the sea half a mile off the community of Santa Claus, two miles north of here, Wednesday.

The pilot, identified as David Beil, 32, of Thousand Oaks by a spokesman for Lockheed-California Co., which was testing the aircraft, was killed.

Lockheed-California described the helicopter as an AH-56A Cheyenne, a rotary-winged craft with a short fixed wing and two rotors.

It was a two-place ship but only the pilot was aboard as it flew along the coast, simulating low-level military attack, with a chase plane close behind.

Witnesses on the beach said the aircraft suddenly began to trail a plume of smoke and that flames appeared. They heard an explosion, and one of them, Jack Hamm, said:

“The tail rotor separated and fell, and the whole aircraft was falling apart, I saw no survivors.”

The fuselage apparently sank, but searchers recovered some wreckage and portions of a body. Part of a helmet stenciled with Beil’s name was washed up on the beach.

An engineering test pilot for Lockheed, Beil was a veteran of the war in Vietnam, the spokesman said.

The helicopter took off from the company’s test facility at the Ventura County Airport in Oxnard. It had been making flights over the coast for about two months.

—Los Angeles Times, Thursday, 13 March 1969, Part II, Page 8, Columns 1–2

A prototype Lockheed AH-56A Cheyenne compound helicopter, just northwest of Ventura County Airport (now, Oxnard Airport, OXR), Oxnard, California, circa 1969. (Lockheed Martin)

A U.S. Army investigation found that while flying at a speed of 190 knots the helicopter’s main rotor blades began oscillating up to 3 feet vertically at the tips, and struck both the tail boom and the cockpit. In a 7 October 1969 article, the Los Angeles Times wrote:

“When the blades dipped that low, they sliced through the fuselage both ahead of and behind the blade pylon. When they sliced through the fuselage forward of the pylon on which they were mounted, they struck the body of pilot Beil, the report indicated.“

David A. Beil had been copilot of Dawdling Dromedary, a U.S. Navy Sikorsky SH-3A Sea King which flew from the aircraft carrier USS Hornet (CVS-12) at San Diego, California, to the USS Franklin D. Roosevelt (CVA-42) at Mayport, Florida, non-stop, 6 March 1965. (See TDiA, 6 March 1965)

A Lockheed AH-56A Cheyenne firing rockets during flight testing. (U.S. Army)

The Lockheed AH-56A Cheyenne 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 at Van Nuys Airport (VNY). It had a four-bladed rigid main rotor, a stub wing, a four-bladed tail rotor and a three-bladed pusher propeller.

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). The prototype empty weight is 12,215 pounds (5,540.6 kilograms), and maximum takeoff weight is 25,880 pounds (11,739 kilograms).

© 2022, Bryan R. Swopes

21 September 1967

Aviation, , , , , , , ,

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 i son display at the Fort Polk Militry Museum,  Fort Polk, Louisiana.

© 2023, Bryan R. Swopes