Lockheed AH-56 Cheyenne: The Incredible Attack Helicopter Decades Ahead of Its Time

it would be nice to imagine technological progress as a smooth straight line onwards and upwards one in which groundbreaking prototypes both absurd and viable are pitched and allowed to battle it out in the marketplace of ideas leaving only the best and most advanced ideas standing as Champions to carry the heavy mantle of responsibility in Mankind's non-stop path towards progress alas were it so easy this channel is littered with examples that thoroughly demonstrate that often the sophistication and viability of a project has little bearing on its adoption and production this is because lingering in the background of any project great or small is a foul spect or a Machiavellian demon of the foulest proportions that cares not for the security of the nation the fighting ability of the enlisted soldier in all the noble pursuit of technological sophistication we speak of course of the politician the politician and those who politic are concerned with their own short-sighted Survival securing victory in their next election securing their next climb up that political ladder the promotion of their own internalized biases and the utter destruction of ideas that happened to Paul fowl of the aforementions we are no strangers to these most wicked of force on this channel the sa80 are dangerously terrible rifle whose flaws were willingly covered up by promotion hungry bureaucracy Rats the Mars m52 which was mysteriously canceled just as it sat poised to take the supersonic trophy for the United Kingdom the tsr-2 which was mysteriously canceled just as the American military industrial complex began to get scared of having a viable overseas competitor look we have covered many examples of the corrosive meddling of the politician on this channel and today we are leafing through the annals of aviation history to examine another type of toxic politics inter-service rivalry today's subject was an advanced American attack helicopter that was poised to be the most advanced thing in the sky to revolutionize helicopter design and set the Benchmark for rotorcraft design for decades to come only to have the rug pulled from under it and be unceremoniously canceled and abandoned thanks to politicking and tribalistic inter-service chest thumping most malevolent and capricious it was an attack helicopter so Advanced that still to this day it stands as one of the fastest ever rotorcraft it had an advanced weapon Suite years ahead of its time and to many it's still considered to be leagues ahead of the helicopter that eventually filled its role over a decade after its cancellation the Boeing ah-64 Apache this is the story of the Lockheed ah-56 Cheyenne the Revolutionary attack helicopter killed by politics [Music] thank you the ah-56 Cheyenne was the end result of a long line of development with numerous precursor Technologies and prototypes all playing the contributing part to this Monumental aircraft the main such precursor technology for the ah-56 was the rigid rotor which is to say a rotor design in which the helicopter blades are fixed to the rotor Hub without hinges and the Hub is fixed the rotor shaft rather than the traditional hinged rotor design found in most helicopters in which hinges let the blades move independently of one another this method of rotor assembly can trace its lineage back as far as 1921 Juan De La Sierra a Spanish aeronautical engineer tried to rigidly attach the rotor Blades of an auto gyro to its hub despite his best efforts he failed to produce a viable design on account of the difficulty in controlling the rotor the idea was again picked up in 1958 by Irv Culver an American aeronautical engineer who presented his eyes ideas for rigidly attaching the rotor Blades of a helicopter to its hub to Lockheed Management in 1958. Culver quickly ran into the same problems as Juan De La Sierra but believed a solution to the excessive gyroscopic moments could be found in the use of a feedback system into the rotor which would allow excessive pitch and roll movements to be controlled further development by Culvert led to the creation of a device known as the moment feedback system which created a compliance factor in the blades which gave them forward pitch momentum of less than a degree subsequently allowing the application of a corrective Feathering input to the opposite blade Culver then went on to demonstrate this Innovation by incorporating it into a radio-controlled model which thoroughly demonstrated the feasibility of the concept and he was subsequently given a test flight Hangar or flight test engineer and two mechanics by Lockheed so that he could further test and refine the concept Culver's work progressed sufficiently that Lockheed soon commissioned a full-scale flying prototype of his new technologies the Lockheed cl475 which first flew in November of 1959. the cl475 was very much a technological test bed in that all emphasis in its design and the majority of the resources allocated to its development went into perfecting its rigid rotor configuration with the rest of the aircraft being comparatively Spartan and utilitarian it was a fabric covered design built around a steel and aluminum frame the landing gear was a crude non-retractable tricycle layout and it was powered by a modest four-cylinder air called Lycoming o360 A1A piston engine developing 140 horsepower which ran to a two-bladed wooden rotor the design proved a hit however and despite its largely crude nature the cl475 proved the real-world viability of a rigid rotor design as Culver's Innovations in conjunction with an upgraded metal three-blade rotor made for an exceptionally responsive and agile yet stable aircraft Lockheed was naturally impressed with these results and he was formally assigned to Lockheed Skunk Works Advanced development programs division where he received the luxuries of both the funding and the facilities that came with such a prestigious assignment lockheed's faith in Culver soon yielded dividends with the extra resources and Personnel of the Skunk Works he quickly developed a more advanced rigid rotor prototype the Lockheed xh-51 which first flew in November of 1961 three years and a day after the maiden Flight of the cl475 the xh-51 was a significantly more advanced design than the cl475 and rather than being a simple proof of concept was a full and true prototype designed to show potential customers the true capabilities of a fully fleshed out and realized rigid rotor helicopter powered by a pratt and Whitney Canada pt-6b9 turboshaft engine producing a healthy 550 horsepower the xh-51 was significantly faster than the cl475 being capable of reaching 257 miles per hour in level flight and 302 miles per hour in a challenge dive for perspective the xh-51's Contemporary the venerable Bell uh-1 Iroquois was capable of 127 miles per hour in level flight and 180 miles per hour in a shallow dive design and development of cutting-edge aircraft is rarely a clear-cut process however and invariably issues were encountered during the testing of the xh-51 one such issue encountered was that despite Culver's great Innovations the aircraft still proved unstable at high speeds which fortunately proved easily remedied by the implementation of a four-blade road system high-speed performance was also further improved with the addition of 4.9 meter long Wings on the second xh-51 prototype which supplemented the rotors by producing lift while in forward flight with all of its Kinks ironed out the xh-51 proved to be an agile stable and above all else blisteringly fast aircraft and Lockheed felt nothing but confidence when from 1962 they began marketing the xh-51 to both Military and Commercial potential customers unfortunately for Lockheed this went badly really badly the problem was there was a very big difference between a fantastic and technically groundbreaking aircraft and a commercially successful one the market didn't want an expensive 300 mile per hour utility helicopter America's Airlines Executives and private Pilots were all perfectly content with their slower more Orthodox and above all else cheaper helicopters and Lockheed failed to secure a single order this commercial failure appeared to be the end of lockheed's dabbling into rigid rotor helicopters the market had spoken the clerks and Lockheed sales department sat twiddling their thumbs and lockheed's profit conscious Executives were beginning to turn on the project in the face of its dubious profitability but then at the 11th Hour when all seemed lost for lockheed's rigid rotorcraft a customer emerged with pockets so stuffed and heavy with plunder that cared not for such asinites as cost and affordability a customer who wants ignored but the most advanced fastest and most lethal helicopter possible and of course this customer was the U.S army all the resources Lockheed poured into its rigid rotor prototypes the cl475 and the xh-51 finally began to return dividends in March of 1963 when the U.S army announced a program to acquire a new class of helicopter a fast agile and above all else dangerous helicopter that could carry weapons in a dedicated platform rather than the jury-rigged Contraptions that had previously carried armaments and this program was dubbed the advanced aerial far support system the timing could not have been better for Lockheed thanks to Irv Culver and his team's dedicated and extensive work on the xh-51 Lockheed had a big bucket full of patterns and potential that could reasonably easily be the a perfect helicopter for this program and thus work on what would become the ah-56 Cheyenne finally commenced [Music] the specifics of the advanced aerial fastball System Program were lofty to say the least it called for a helicopter with a dash speed an emergency high power speed which can only be sustained for a few minutes before one damages mechanical systems of over 220 kilometers an hour a cruising normal speed of 196 kilometers an hour a ferry range that maximum range of the aircraft when it has all non-essential components stripped and fuel tanks brimmed so it can be varied from place to place of 700 miles and for it to be able to hover at altitudes of 5000 feet or 1 800 meters 12 companies submitted design to the US Army with all of the big players of America's Aviation scene making a bid for the contract but only Sikorsky and lockheed's proposals were shortlisted the former submitted the Sikorsky s66 and the latter submitted the ah-56 Cheyenne the s66 looked very similar to the Lockheed ah-56 Cheyenne and indeed both were Advanced compound helicopters designed leagues ahead of anything then in the U.S Army's inventory but for want of a better description the s66 was more of a Bargain Basement design compared to the ah-56 with the program coming in at a mere 66 million dollars compared to the ah-56 at 106 million dollars not to decry the Sikorsky proposal as crude however rather it is indicative of the Absurd levels of sophistication and Innovation Lockheed proposed for the ah-56 the s66 had a Rota prop tail rotor which could rotate its axis through a 90 degree range to act both at a conventional anti-torque rotor in horizontal flight and as a pusher propeller thereby transforming the s66 into a compound aircraft in cruising flight this was a great Innovation certainly but lockheed's Innovations in stability and control just blew it out of the water the proposed tokorski s66 would have produced 3439 horsepower being powered by lecoming t-55 turboshaft engine and able to achieve a dash speed of 390 kilometers per hour cruising speed of 340 kilometers per hour a ferry range of 3500 kilometers and is able to hover at altitudes of 5500 feet this was a fantastic effort by Sikorsky for sure but nothing compared to the Lockheed ah-56 which was leagues above the s66 both literally and figuratively and it was selected for further development by the U.S army over sikorski's craft the ah-56 decimated the advanced aerial fast sport system specification with a dash speed of over 400 kilometers per hour a ferry range of 3 900 kilometers and it was able to hover at an altitude of 6000 feet or 1800 meters furthermore it featured a retractable landing gear wings that spanned 27 feet and was powered by a general electric t-64 ge-16 turbine engine mated to a four-bladed gyro stabilized rigid motor that produced 3900 22 horsepower it had a tail mounted anti-talk rotor in line with basically every helicopter ever made but complemented this with an additional push-up propeller also mounted on the tail boom this push of propeller was also reversible allowing the ah-56 to decelerate and Brake during vertical Dives allowing the pilot to enter a dive then reverse thrust on The Pusher to slow the aircraft down considerably allowing him plenty of time to fixate on the target fire and then start his recovery during vertical and hovering flight all power was sent to the main rotor and the torque rotor on the tail boom giving fly control relative to a normal helicopter but upon transitioning to level flight all but 700 horsepower from its Mighty power was sent to the aforementioned push propeller this made the main road to all but redundant for generating any lift Beyond residual windmilling but this was in turn offset by lift generator by the craft short Wings what's more while the ah-56 may have had familiar flight control during vertical and hovering flight its performance was anything but familiar with long Advanced fixed gyro stabilized rotor design giving it performance that is arguably unmatched this day the lack of hinges on its main rotor design meant that the airframe would follow the rotors directly with no delay or inaccuracy making it incredibly intuitive to control the gyroscopic control also meant that the h-56 was immune to all but the most extreme changes in its center of gravity being able to handle offset loads of up to 5 meters without any difficulty in control or input responsiveness the ah-64s Revolutionary performance was complemented by similarly exceptional weapon system its primary Armament was a fearsome 30 millimeter xm140 autocannon mounted in a belly gun pod which gave a full 360 degree Traverse with Advanced armor-piercing rounds meaning that with this gun alone it definitely had the capacity to ruin anybody's day who was unfortunately in the crosshairs complementing the xm-130 cannon was a front-nosed turret carrying an additional secondary weapon either a 40 millimeter xm-129 grenade launcher or a 7.62 millimeter m134 minigun with 100 degrees of Traverse either side of the center line the aforementioned lineup is all well and dandy of course and no doubt I would have had infantry or lightly armored targets reaching for the toilet paper upon the ah-64's arrival into a Hot Zone but what about tanks how would the ah-64 fend off the vast armored Columns of the Red Army that every defense analyst of the time predicted was imminently about to pour through jackpot Charlie Lockheed answered this question with six hardpoints mounted on the ah-56 short Wings to which could either be fitted 60 aw missiles or 2.75 inch rocket pods these hard points were also compatible with a range of gun pods all further increasing The h-56's lethality towards soft and lightly armored targets these gun pods seem to be pre-existing designs bought off the shelf and not designed specifically for the ah-56 such as the suu 11a 7.62 millimeter minigun pod the SU u12a50 caliber gun pod or the XM 1340 millimeter grenade launcher pod to further complement this terrifying complement of weapons the ah-56 was fitted with an incredibly Advanced weapon sighting system consisting of night vision equipment and aiming cameras which all linked back to a helmet mounted side for the Gunner this is early how a mounted site was further complemented by the Gunner seat being fitted with a full 360 degree rotation so wherever he looked the guns looked furthermore a fire control computer took the information from the gun as how we mounted sight and through the use of two gyroscopes connected to a Doppler radar kept all weapons on target for massage the computer compensated for wind and the movement of the Target on the ground meaning that the Gunner could fire and forget and not have to adjust the massage trajectory mid-flight for the guns the varkodro computer automatically compensated the bullet drop and wind thanks to the stability of its rigid rotor design and the computer-controlled weapons the ah-56 was also exceptionally accurate with the 30 millimeter cannon consistently being able to hit a 25cm meter Target three kilometers away to say the top brass of the US Army were enthusiastic about the ah-56 would be a gross understatement and following our review of its features is not exactly hard to see why remember that attack helicopter technology of the 1950s and early 1960s otherwise essentially amounted to inaccurate rocket pods jury rigged to the side of slow and crude transport helicopters the US Army took to the ah-56 Shand like a pig to Mark and following an initial order of 10 prototype units in 1965 placed an initial production order for 375 aircraft in January 1968. [Music] all seemed Rosy for the ah-56 blockade had produced a simply phenomenal aircraft years ahead of its time and the military money man who paid lockheed's bills seemed to agree that the ah-56 was indeed the best thing since sliced bread but alas a happy ending for the age 56 was not meant to be not even three percent of that initial order of 375 would be produced with a mere 10 airframes leaving the assembly line before the project was ultimately canned and this phenomenal aircraft was just reduced to nothing but a relic Gathering dust in the corners of an aviation museum as a monument to something great that could have been as we briefly discussed at the start of today's video the United States Air Force hated the ah-56 Shan a cabal of senior officers perceived the development of the age 56 as a most grave and personal insult they had their emotional knee-jerks behind various legitimate and professional facade cards but when you go back and read primary documentation from the time it becomes quite apparent that the Air Force officers involved were little more than petulant children throwing their dummies from the pram because they're envious of another child's toy this at face value may sound ridiculous Air Force officers of the time were intelligent and well-paid thinking men surely they cared about the defense of their nation and other people above all else right there's no way they would sabotage game-changing Hardware just so their branch of the service could beat its chest and have the nicest toys well of course they did they were human and as tribalistic and inclined towards prejudices you or me regardless of how many medals Uncle Sam strapped onto their chest what are the key arguments used by the anti-air36 lobby was the 1948 Key West agreement this agreement colloquially shorthand for the functions of the Armed Forces and The Joint Chiefs of Staff affirmed the role of Aviation within the American Navy Army and the then newly created Air Force giving clear roles and responsibilities to each of the aforementioned Services air arms to simplify somewhat this agreement meant that the Army could use rotorcraft for troop deployment and Logistics but the close air support would be provided by a fixed-wing aircraft from the Air Force the Air Force argued that the advanced nature and capabilities of the ah-56 made an overlap into their close air support role and as per the agreement such overlaps were meant to be avoided in order to prevent the wasting of resources they pointed to the Douglas A1 Skyraider they currently had in service in the Fairchild Republic A10 Thunderbolt that they had in development as proof that close air support needs were already being adequately met by their aircraft the Department of Defense launched a study to investigate the Air Force's claims that static paired the h-56 Shan from the Army the Prototype A-10 from the Air Force and finally the McDonald Douglas av-8b Harrier from the Marines as the Air Force was also moaning about that one one two this study published in 1973 concluded that all three aircraft were so radically different that there was no overlap in their role citing the harrier's vital ability as an essential component of carrier operations and the eight and armored frames an essential component of close air support operations and the age-56 ability to hover and linger in precisely at multiple targets with its Advanced targeted computer as something unable to be offered by the Air Force's aircraft inventory but of course this study did little to quell the anti-ah-56 lobby in the Air Force One Air Force generally was particularly zealous in his Crusade against the age 56 was when General William Moyer Moyer stands out in terms of his egregious conduct more so than any other Air Force General who opposed the h-56 he was willing to lie and slander in order to see his prejudices satisfied this is typified by his testimony before the Senate on the 22nd of October 1971 in which he used exaggerated and out of context claims about the role of the helicopter in the failed operation Lamb song 719 to undermine not just the ah-56 but the very concept of the attack helicopter as if the political attacks from the Air Force weren't bad enough at the age 56 it also had to contend with one of the most frustrating components of American Military procurement corruption I'm sorry lobbying this lobbying came from Bell manufacturers for the ah1 cobra attack helicopter which was first procured by the United States Army in 1967 as a cheap and cheerful interim measure to tide the Army over into a more advanced and sophisticated designs could be put into service mysteriously many senators and congressmen who were previously very in favor of an advanced highly sophisticated attack helicopter moved towards favoring the cheap and cheerful ah1 Cobra after dinners and outings with bell Executives but while we know there was political meddling involved in the cancellation of the age 56 as ever there is two sides to every story and as we have seen before in similar videos to discussing political meddling in Aerospace and defense programs often there are very genuine flaws and downsides to a seemingly groundbreaking design that complicate the story Beyond Simple political meddling and we as historians left trying to decide which factor or is more important in killing the design the flaws simply being used as a weapon by partisan and Prejudiced actors determined to kill a project or these flaws being serious enough to genuinely undermine the viability of a seemingly otherwise world-beating project the ah-56 was no exception to this and the project did have some very real flaws regardless of how groundbreaking the overall design may have been one of the more pressing concerns was the occasional tendency of the rigid rotor motor to unintentionally vibrate once per two main rotor Revolutions in certain conditions dubbed the half P hop this vibration and the jolt it would send throughout the entire airframe could cause the pilot to put too much input into control stick and unintentionally maneuver the aircraft normally this was an inconvenience throwing the gun off Target or simply requiring the crew to change their underpants after the unexpected jolt but tragically this floor proved fatal on the 12th of March 1969 when the roads were on Prototype number three struck the fuselage during a half P hop this sheared the rotor from its row to Mast and sent the craft into an unrecoverable dive killing the test pilot David Beale this tragic accident was an absolute godsend for the U.S Air Force who fully exploited the incident to help build their case about the ah-56's unviability but there is more Nuance to the accident that shows the story really is not that simple firstly the test flight was specifically being conducted to assess the full extent of danger presented by the half b-hop and accordingly safety measures normally in place were removed for the test flight and David Beale was on orders to go out of his way to repeatedly induce the problem to its fullest extent so the accident although certainly tragic was hardly representative of the real world danger posed by the issue what's more day to gathered from the subsequent crash investigation led to the problem being fully eliminated so in light of the fact this problem was solved before the Project's cancellation it's hardly damning evidence of a fatal flaw in the age 56 but oh so often in military procurement when ego and tribalistic chess beating gets involved the technical merits of an aircraft and the hard work of its designers counts for very little compared to the spin that could be sold to Congressman whose pampered and callous free hands no little of the true realities of the military the Army tried to fight back and to display the merits of the age-56 Shan over its competitors in January 1972 a special Army task was under General marks re-evaluated the requirements for an attack helicopter Box's task force conducted flight evaluations of the age-56 along with two industry alternatives for comparison the Bell 309 king cobra and Sikorsky s-67 Blackhawk analysis of the three helicopters determined the Bellin Sikorski helicopters could not fill the army resp environments so now we arrive at the pivotal moment we know all about the advanced specifications of the ah-56 as well as its Advocates and its detractors so now we have to ask the question was the spin of the anti-ah-56 detractors good enough to kill the project well yeah it was the lobbying eventually proved too much and the program was canceled by the secretary of the Army on the 9th of August 1972. the ah-56 the hyper-advanced helicopter that once sat Poise to revolutionize the aviation world found itself either confined to the scrap Heap or shipped to various museums across the U.S where they said to this day Gathering dust as failed testimonies to what could have been a truly sad end for such a phenomenal aircraft [Music] we've only been able to scratch at the surface of the real story today but fortunately the rise and fall of the ah-56 has been written about extensively by historians and there exists a plethora of great materials available for anyone wishing to study it further in particular the author of today's piece would recommend inter-service rivalry and air power in the Vietnam War by Professor Ian horwood and with that bit of recommended reading we'll end today's video thank you for watching foreign [Music]

Channel: Megaprojects

Views: 1,110,429

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Id: _6GAp8yO7l0

Length: 27min 34sec (1654 seconds)

Published: Wed Aug 31 2022