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Lockheed AH-56 Cheyenne – First and Last Failed to Be a US Air Force Fighter

The AH-56 Cheyenne was Lockheed’s first and only foray into development of a production helicopter. In many respects, however, the Cheyenne was neither a true helicopter nor was it a true airplane – in many ways that today’s tilt-rotor V-22 Osprey defies conventional categorization as a helicopter.

The performance specifications inherent in the design allowed for the Cheyenne system to reach unheard speeds for any helicopter type before it – or today for that matter. The system was initially conceived of as an escort for the fast-moving helicopter transports ferrying troops into combat hot zones.

Lockheed AH-56 Cheyenne

As the AH-56 program developed, senior US Army personnel began envisioning more roles for the already impressive AH-56 to undertake. In the end, however, the dream was unfulfilled for many-an-obstacle stood in the way of the Cheyenne eventually leading up to its cancellation.

The Situation

In the mid-1950s, the concept of armed helicopters was taking hold with the army leaders of the world. Over a decade before, the German Luftwaffe was able to field the first real operational fleet of helicopters but this occurred only in limited numbers. What this did, however, was begin to pave the way for other like-designs to take hold and the US Army was no exception to such thinking.

Lockheed AH-56 Cheyenne

Early attempts by the US Army were made by simply adding machine guns as self-defense measures to existing transport helicopters though this by no means was the solution it sought. The arrival of the turbine-powered Bell UH-1 “Huey” and the Vietnam War allowed for even greater thinking in the area, for this capable systems could be armed well enough and provide performance to keep up with the transports she was charged with protecting.

UH-1’s were ultimately trialled and fitted with various arrangements of rocket pods, missiles, automatic grenade launchers, miniguns and machine guns. The first UH-1’s arrived in Southeast Asia in 1962.

Lockheed AH-56 Cheyenne

While the UH-1 was capable of keeping up with its older transport counterparts, the arrival of the twin-engine Boeing-Vertol CH-47 Chinook transport series once again changed everything. Chinooks could easily outpace their UH-1 brethren, making their armed escort partners seemingly useless where pure speed over contested areas was the call of the day.

As such, the US Army started penciling out plans for a new dedicated helicopter escort capable of saturating the area ahead with strike fighter-like firepower while being able to survive in a low-altitude environment.

Lockheed AH-56 Cheyenne

Strike fighters of the day proved adequate suppressive components, but this up to a point. Since they operated under the banner of the US Air Force (unlike in World War 2), the US Army was at the mercy of their limitations. J

ets still relied on their thirsty engines limiting their loitering times and were built for speed, essentially restricting many of these hotrods to single passes over a given target or target area while their targeting and munitions capabilities were more reserved for annihilating large target areas – not the confined target areas of assisting friendly troops on the ground as close-support aircraft.

Lockheed AH-56 Cheyenne

Many strike fighters had to wait on the ground for the call to help, wasting precious minutes in take-off and journey time to the target. A capable helicopter, at least one armed and dedicated for the role for the job, could be waiting just outside of the hot zone to participate in action at a moment’s notice.

The Requirement

The US Army began looking into acquiring their own solution apart from the US Air Force. This included testing out other implements such as the Douglas A-4 Skyhawk and an early form of the AV-8 Harrier jump jet. The US Air Force, long holding to the belief that the fixed-wing realm was theirs and theirs alone, lobbied hard against the US Army acquiring their own fixed-wing strike aircraft – an argument that the US Air Force ultimately won.

Lockheed AH-56 Cheyenne

As such, the US Air Force would continue to supply the airpower for the US Army’s needs, though a new set of requirements were written for the Air Force to accomplish this. Some of the more outstanding byproducts of this new initiative would become the twin-engine Rockwell OV-10 Bronco and the single-engine Douglas A-1 Skyraider, each implement proving adequate in the close-support role, but not the solution that the US Army was envisioning.

The ever-changing tactics of a resilient enemy in Vietnam would prove that. While the US Army could not field their own fixed-wing aircraft, they were allowed to keep their own contingent of armed helicopters. To that, the US Army presented the Advanced Aerial Fire Support System program in search for their first dedicated attack helicopter platform.

Lockheed AH-56 Cheyenne

About this time, Bell produced their private venture Bell 209 model which ultimately became the successful AH-1 HueyCobra (or simply “Cobra”), fulfilling the gunship role of the Cheyenne. These systems held some inherent benefits such as their successful Bell pedigree (ala the UH-1), a slim forward profile and adequate survival capabilities for the crew.

Their limitations – when compared to the Cheyenne – was their lack of an advanced fire control system, limited armament capabilities and limited endurance. Despite this, the inevitable faltering of the Cheyenne project would give rise to the Cobra gunship and decades of faithful service thereafter before being replaced by the Hughes AH-64 Apache gunship.

Lockheed AH-56 Cheyenne

While Bell was working through their Model 209, Sikorsky, Convair and Lockheed submitted proposals to fulfill the Army need. Sikorsky showcased a promising design while Convair’s approach was seemingly out of this world.

Convair put forth their Model 49, a VTOL-capable system built around a protected cylindrical engine shroud, armed to the teeth and – perhaps most distinctly -with a positional cockpit containing pilot and co-pilot. The cockpit could be set to a horizontal position when in flight and similarly leveled in hover, this while the rest of the fuselage stayed vertical.

Lockheed AH-56 Cheyenne

Lockheed unveiled its CL-840 model idea, an ambitious and highly-advanced single-engine design that seated two in tandem. The aircraft would feature a sophisticated fire-control system and performance promises surpassing anything in the world by helicopter terms.

The Lockheed design also featured a “rigid rotor system”, which in itself was quite a different approach to the more flexible systems of conventional and previous helicopter designs. The rigid rotor system promised unparallel handling and performance more akin to that of a fighter than a helicopter.

Previous attempts as a rigid rotor met in failure or produced such complexities beyond the realm of full-scale production within a budget. Lockheed felt it had found an answer to these issues and then some.


Lockheed produced, at first, a small radio-controlled model to test out their rigid rotor system concept, ultimately proving the idea sound. This was followed by Model CL-475, a full-scale, multi-seat helicopter with an initial two-bladed main rotor. This graduated to become a three-bladed main rotor made of aluminum and further live tests followed.

The XH-51 was a further light helicopter design that proved successful in testing but – much to Lockheed’s misfortune – was never produced. The CL-475 and the XH-51 both survived their development histories to become museum showpieces. The final competition now fell between Lockheed and Sikorsky to which Lockheed was officially announced the winner.

Lockheed AH-56 Cheyenne

The US Army contract ($12,750,000) was signed on March 23rd, 1966 and called for ten aircraft to be produced under the AH-56 designation.

Secretary of Defense Robert McNamara put forth a new initiative to help ease along the development and procurement of future defense systems. This essentially involved contractors and defense branches committing to a product regardless of it living up to expectations.

Essentially, this new procurement policy covered a weapon system from design and development to testing and purchase. Contractors hated the idea as they would have to commit to a fixed price assessment of the product while it was still in development, a period when costs almost certainly tend to rise especially when dealing with new-fangled technologies.

Lockheed AH-56 Cheyenne

The defensive branches were equally negative on the idea for it forced them to commit to an unproven product before the system was properly tested and cleared for operational duty. In a number of ways, McNamara’s initiative would only add to the demise of the Cheyenne’s potential and promising legacy yet to be written.

The first prototype AH-56 was presented to the US Army on May 3rd, 1967. First flight of the AH-56 was completed on September 22nd, 1967 using the second Cheyenne prototype with test pilot Don Segner at the controls. The flight lasted 26 minutes and was successful on the whole, proving the design sound, responsive and reliable. The first public flight of the Cheyenne occurred on December 12th of that year, again with Segner at the controls.

Lockheed AH-56 Cheyenne

By this time, the AH-56 was already clocked just under 200 miles per hour while other abilities were clearly distinguishing her from anything that had flown before. She showcased the uncanny ability to hover forward and in reverse without so much as tilting her fuselage – a feat made wholly possible by her pusher propeller system.

Production was penciled to begin on September 20th, 1968 with deliveries beginning a year later. It was to take place at Lockheed assembly plants in Van Nuys, Burbank then finally completed systems would be handled at Palmdale, California.

Due to budgetary constraints, an initial US Army order for 600 Cheyennes was curtailed to 375. The contract was given to Lockheed in January of 1968 though by the middle of 1969, the whole production contract was cancelled after delays and an in-air accident killed a test pilot.