Back Lockheed AH-56 "Cheyenne"
1967

Lockheed AH-56 "Cheyenne"

The Lockheed AH-56 Cheyenne attack helicopter was created in response to the US Army's need for a fast, armoured and heavily armed helicopter to supplement the escort/attack role.

The Cheyenne featured a revolutionary compound helicopter configuration as well as a gyro-controlled rigid-rotor and three-bladed pusher tail propeller as well as a four-bladed anti-torque rotor. It had small wings attached to the side of the fuselage that could off-load the rotor during high speed flight. The helicopter was powered by a 4350shp General Electric T64-GE-16 gas turbine engine derated to 3925shp. The Cheyenne could accommodate a crew of two sitting in tandem in the enclosed cockpit with the gunner co-pilot in front of the pilot on a gun platform which could swivel 360°. A second gun system was housed in a nose turret. Six under-wing attachment points were used for missiles or rocket pods. The sophisticated weapon-sighting system included night-vision equipment and a helmet-gun sight.

The Cheyenne at first proved highly capable and in December 1967 the Army ordered a production batch of 375 Cheyennes. During further flight testing however there were three crashes. The helicopter proved unstable at high speeds in excess of 320km/h. After the third crash in 1969, when the main rotor collided with the fuselage, the production order was delayed. Further design modifications took place and by 1972 most of the Cheyennes' faults were cured but the program was cancelled due to budgetary problems. There were ten Cheyennes built.

Armed with a nose turret, with either a 7.62mm minigun or 30mm XM140 cannon, or a 40mm XM 129 grenade launcher, wing mounted TOW missiles or 2.75mm rocket pods, the Cheyenne could cruise at 388kmh with a max speed of 407km/h. It had a rate of climb in excess of 1025m/min and a range of 1970km.

P.Allen "The Helicopter", 1996

Lockheed AH-56 "Cheyenne"

The ambitious AH-56 Cheyenne helicopter, with which Lockheed hoped to establish a foothold in the rotary wing sector, was in fact a resounding failure for the Californian company. It featured a rigid main and tail rotor, which Lockheed had been researching since 1959 — a rigid rotor enables helicopters to perform genuine aerobatic manoeuvres.

The AH-56A Cheyenne was driven by a General Electric T64 turbine delivering over 3400shp. It had a stub wing with an 8m span and an area of 24m2, attachment points for six underwing stores weighing 900kg each, a streamlined fuselage with a tandem cabin seating arrangement, retractable front landing gear units, a fixed tailwheel, a rigid four-blade anti-torque tail rotor and three-blade pusher propeller at the tip of the tail boom. However the Cheyenne was technically too complicated and US Army orders were cancelled and development suspended in 1972.

G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984

Lockheed AH-56 "Cheyenne"

Developed as Lockheed's entry in the Army's Advanced Aerial Fire Support System (AAFSS) competition, the Cheyenne was a highly sophisticated compound rotorcraft whose design incorporated several features pioneered in Lockheed's earlier XH-51A. The Cheyenne was named winner of the AAFSS contest in March 1966, at which time Lockheed was awarded an Army contract for the production of ten YAH-56A prototypes. The first of these made its maiden flight in September 1967, and all ten aircraft (serials 66-8826 through -8835) had been delivered to the Army for flight testing by July 1968. In January of that year the Army had placed an initial order for 375 production machines, and the ten prototypes were subsequently redesignated AH-56A in early 1969.

The Cheyenne was, to say the least, a rather exotic-looking aircraft. The forward end of its long and narrow fuselage was dominated by an outsized segmented canopy covering a tandem, two-seat cockpit, while the tailboom supported a large ventral fin, a conventional anti-torque tail rotor, and a decidedly unconventional pusher propeller. A pair of small, low-set stub wings fixed to the fuselage sides contributed to the Cheyenne's hybrid look, as did its retractable, wheeled main landing gear. The AH-56A's ungainly appearance was deceptive, however, for in flight the craft was amazingly agile and extremely fast. The Cheyenne's impressive performance was the product of an innovative propulsion system built around a 3435shp General Electric shaft turbine engine. This powerplant drove a rigid, four-bladed, gyro-stabilized main rotor, the tail-mounted anti-torque rotor, and the pusher propeller at the extreme end of the tailboom. During vertical and hovering flight all power was applied to the main and anti-torque rotors, while during forward flight all but about 700shp was shafted to the pusher propeller. In forward flight lift was generated by the stub wings and windmilling main rotor, and in absolutely 'clean' configuration the AH-56A was capable of sea-level speeds in excess of 400kph.

The Army's AAFSS specifications had called for an aircraft capable of undertaking armed escort, long range interdiction, fire support, and anti-tank operations by day or night and in all weathers, and the Cheyenne had been armed and equipped accordingly. The AH-56A's armament consisted of a nose turret housing either an XM129 40mm automatic grenade launcher or XM134 7.62mm multi-barrelled minigun, a 30mm cannon mounted in a revolving belly turret, and an impressive number of TOW anti-tank missiles and/or pods of 2.75 inch unguided rockets carried on underwing hardpoints. The Cheyenne's day and night, all-weather flight capability was based on an extensive avionics suite which included automatic terrain-following radar, Doppler radar, an inertial navigation unit, and an automatic flight control system that allowed high-speed flight at altitudes as low as fifteen feet.

Despite its technological sophistication, or perhaps because of it, the AH-56A was fated never to enter regular Army service. The flight test programme revealed several significant problems with the aircraft's innovative propulsion system, problems which ultimately resulted in the fatal crash of one of the ten prototypes. In addition, by March 1979 significant cost overruns had increased the per-unit Cheyenne price by more than $500.000, an increase that was unacceptable in light of the Army's continued high expenditures in support of operations in Vietnam. And, finally, the USAF had become increasingly vocal in its opposition to the Army's acquisition of an aircraft as capable as the Cheyenne, and continued to push for the cancellation of the AH-56 project. The Army ultimately decided to develop a cheaper and less sophisicated helicopter in place of the Cheyenne, and in August 1972 formally terminated the AH-56 programme.

S.Harding "U.S.Army Aircraft since 1947", 1990

FACTS AND FIGURES

- Since the Cheyenne project, Lockheed has not put a military or civil helicopter into production.

- Power of the T64 engine was increased to 3,922hp during testing.

- Cancellation, in May 1969, came just six months before production began.

- In common with other US Army helicopters, the Cheyenne was named after a native American tribe.

- The highly manoeuvrable AH-56 was found to be a stable weapons platform.

- The other short-listed AAFSS prototype was the Sikorsky S-66.


Photo Gallery 

An AH-56A with underwing stores and a 30mm antitank cannon in a turret under the fuselage

Technical data for AH-56A "Cheyenne"

Crew: 2, engine: 1 x General Electric T64-GE-16 rated at 2580kW, main rotor diameter: 15.36m, length: 18.30m, height: 4.10m, take-off weight: 13600kg, empty weight: 5320kg, max speed: 408km/h

Comments1-20 21-40 41-60
T- BIRD, 07.11.2020reply

GREAT KILLER

Monterey, e-mail, 14.03.2016reply

Hi all,
My dad worked photography /filming documentation for the Cheyenne flight test program; I believe it was from the '69 to '71 time frame. I know part of his work included filming weapons testing; I'm not sure if he did any chase plane filming himself, but he's talked about the program using P-51 Mustangs outfitted with camera mounts for filming.
I can tell that working on the Cheyenne program was one of his most exciting and rewarding experiences. He gets that far away look and a gleam in his eye whenever he tells me stories...
At one point he had a few original photos from the program but they are long gone; lost before I was born. Does anyone have a high-quality collection of pictures they could send me, digitally or otherwise? I would love to show them to my dad and see if he was behind the camera for any of them!

Joe W..Duran, e-mail, 13.12.2015reply

I worked as a Spare Parts Analyst for Lockheed on the H-56, for a little over a year; it was a beautiful aircraft.
Something like dream with all the new innovations for that time.

NeoConShooter, e-mail, 12.12.2015reply

I was working for DoD some time ago when this chopper came up for discussion and we all agreed, with two decades of hind sight, that this chopper was too expensive, complicated and had too much of the wrong type of performance and not enough of the right kind. It's cancellation was well deserved. It was not as good as it could be flying NOE and all the excess performance added weight that precluded better NOE and drove the cost up. No mater how fast it was, that was speed you had a great deal of trouble using and it restricted the performance that you did need. Choppers are not fast enough to dodge missiles, they must avoid them by limiting exposure that is NOE!

BlueMax 39, e-mail, 29.07.2010reply

I had twin back to back tours flying Cobra's with the 1st Air Cavalry, RVN. Naturally all the Snake drivers were enthusiastic about this superb machine. Lockheed hit a home run with this aircraft...and Congress failed to field it. It is beyond shameful that politics took precedence over exceptional engineering! The Cheyenne would have upped the stakes with Soviet Union, thereby inspiring them to produce a higher-quality helicopter. In the long run this competitiveness would have benefitted the entire industry...Worldwide. MBB fielded their rigid rotor. It is in widespread use today, globally. Manoeuvrability is not the only beneficial aspect of this design. The Cheyenne would have been much more durable dealing with severe weather and operating out of difficult, sloped environments, than anything built to date. Whats up with that?

Vic, e-mail, 16.09.2010reply

Virtually all electric and electronic systems were in boxes that were rack mounted and removable. The Crew Chief plugged in a test set and changed out the faulty box. Fast turn around but expensive spare parts management. Gunner in front was on a seat that spun 360 degrees to stay on target. Many pilots who tried the front seat, head buried in the sight, had air sickness problems. Non pilots did pretty good. Maybe Berch knows who gave me a dollar ride at Ft. Hood in probably 1970. I was an AMOC 64823 Commanding a DS company at the time.

LS BANTER, e-mail, 27.09.2010reply

The one at FORT RUCKER in ALABAMA is still thare. Under going restoration as of last year. Very good looking machine indeed!

Arthur Moss, e-mail, 09.10.2010reply

I helped write the Cheyene proposal, and wrote a portion of the L-286 Flight handBook. Another feature of the Cheyene was self-deployment(CA to Hawaii). I also was in the position at LAC to know the C5-B was supposed to get the bigger CF6-80's that are being installed now. The AF is still dumb, as the airlines use all 60K Lb thrust with little reduction in reliability. Brilliant AF & Congress (NOT). WE are spending millions of research $ trying to accomplish what exists, and has been proven.

bob, e-mail, 05.03.2011reply

theres one on display at ft campbell kentucky

Steven, 07.12.2011reply

I dont know, looks a little to big making it quite an easy to find target. Apache and Cobras are smaller and so are more difficult to spot from a distance to warn AA gunners or SAM sites.

Snake, e-mail, 18.07.2012reply

To put into perspective how much better an almost 50 year old design is than the AH64 Apache in performance alone:

AH56 Cheyenne
Maximum speed: 212 knots (244 mph, 393 km /h)
Cruise speed: 195 kn (225 mph, 362 km /h)
Range: 1,063 nmi (1,225 mi, 1,971 km)
Service ceiling: 20,000 ft (6,100 m)
Rate of climb: 3,000 ft /min (15.23 m /s)

AH64 Apache
Maximum speed: 158 knots (182 mph, 293 km /h)
Cruise speed: 143 knots (165 mph, 265 km /h)
Range: 257 nmi (295 mi, 476 km) with Longbow radar mast
Service ceiling: 21,000 ft (6,400 m) minimum loaded
Rate of climb: 2,500 ft /min (12.7 m /s)

Bell Helicopter and the USAF killed the AH-56 Cheyenne. Lockheed exceeded the requirements of the contract and to this day would smoke an Apache in a one off competition. There were two losses related only to P-Hop, one off the coast of CA resulting only because the safety mechanism had been disabled for the test and the other in a wind tunnel test where it was overlooked that the functional testing required the aircraft to move not remain bolted in stationary frame. The resulting out of balance effect and oscillation literally tore the AH56 apart in the wind tunnel.

Lockheed was ahead of it's time but the underdog from the start.

Kelly, e-mail, 05.07.2014reply

Jonassen
My Dad was the pilot that got killed in the March 12, 1969 crash. I know there is a video out there was wondering if anyone knew anything about that. Also any information about other pilots and the Cheyenne program would be greatly appreciated.

Tony Romero, e-mail, 10.07.2020 Kelly

Hello Kelly,

It's been a long time; how are you? It'd be great to hear from you.

ATB,

Tony Romero

reply

Doug Devine, e-mail, 05.06.2020 Kelly

Kelly: I knew your Dad. I flew helicopters for Lockheed. Dave & Jan had come to our house for dinner, early 1969 I revere knowing your Dad. My recall is that he held double engineering degrees and had the same Naval Flight Training as I did. I would look forward to hearing from you.

reply

Samuel Montao, e-mail, 17.07.2010reply

Es muy ineressante, pero podran, talvez, tener algunas imgenes de los cohetes de 23.75mm. Desde Bolivia un cordial saludo

Sandy Magar-Speed, e-mail, 14.04.2010reply

My father, Claud R. Magar Jr. was with the Cheyenne program from the early 60's at Ft. Eustus, then on to Bell Helicopter in 1966-1967, to Vietnam with the 3rd AVN Co, and then 5 years at Yuma Proving Grounds, where he was often TDY to Lockheed in Van Nuys. I'd love to hear the stories of people who were with the program and knew him, or knew of the Cheyenne project. My mother, a former WAC was the first woman to fly in the Cheyenne. The guys flying them at Arlington, Tx Bell Helicopter put her in a flight suit and took her for a ride in 1966.

APHELY, e-mail, 24.03.2010reply

c'est un trs belle appareille que vous avez chers amis amricain.Mais es ce qu'il est plus fprt que l'appache? parce que contrairement a son cousin l'appache il n'est pas trs mdiatique

Jim Farrar, e-mail, 10.03.2010reply

I was at Ft.Rucker in 1971 and there was one in the museum.It had the cyclic stick mounted on the right side of the cocpit.It was complete except some instruments were missing from instrument panel.Yes,it was the best A /H ever built.

Bart Maham, e-mail, 14.01.2010reply

If you're on the way to Hampton Roads Virginia get off at Fort Eustis. Tell the gate guard you want to visit the Museum and you'll see a Cheyenne there. 30 minute detour if you can tear yourself away from this really cool museum. Have you ever seen a US Army Locomotive? An Army "flying saucer" Enjoy.

atphelo, e-mail, 18.12.2009reply

Well, it wasn't the Cheyenne that crashed at Farnborough, but the Sikorsky S-67, Sikorsky's competition to the Cheyenne. And it was 1974 (I should have remembered that because I was in ABu Dhabi in '74). So much for an old fart memories...

Atphelo, e-mail, 18.12.2009reply

I remember following the development of the Cheyenne after getting out of the army in 1970. The tactics we developed and used in Vietnam in '68 (advancing from the old "C" model into the AH-1G) where being changed rapidly while I was in Germany with NOE (nap or the earth) and the first NVG with the idea that someday, we would be trying to slow down the Russians in their push to the sea ( which never happened, thank God). But we were all watching the Cheyenne being developed and I was working for Bristow Helicopters, Abu Dhabi, in 1972 when word that the Cheyenne on demonstration at the Farnborough Air Show in England had crashed. It was doing a low level roll and simply flew into the ground, destroying the AC and killing the crew. It was shortly after that when we heard the Cheyenne program was dead. I'm sure there is archival video of the accident somewhere. I remember seeing it back then. Amazing machine for the time and, according to you young guys, sounds like a much needed machine for today's environment...

Cobra, 08.10.2009reply

Oops, I meant Whiskers64

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