A Cheyenne warrior in 1/72

[JayBee]

I saw it live on TV, pretty damned shocking is all I can describe it.

[PR19_Kit]

I saw it live on TV, pretty damned shocking is all I can describe it.

It certainly was, there was a deathly hush right across the airfield after the impact, and it went on for some time. The exact opposite to John Derry's DH110 crash, which I also had the misfortune to observe at a very early age. That time it was chaotic, a vast amount of noise, alarms, people shouting etc.

Bad memories..... 

[KiwiZac]

I've seen photos of the crash, just horrendous. I think when I get around to building one I should do two - a whiffed AAC one and one version of the prototype in tribute to Kurt Cannon and his passenger. Kit, I can't imagine how that must have been. I grew up watching the BBC series Reach For The Skies on video, which had footage of the 110 crash, so I know what you mean...albeit very much second-hand. I guess I don't realise how fortunate I am to have never seen an airshow accident worse than a Bristol Fighter breaking its tailskid on landing.

The S-67 was such a sleek, beautiful machine and - aside from the human tragedy at Farnborough - it's a real shame no-one picked it up. Israel is a buyer I've heard in several places, and it flew to US bases in West Germany also. There are some great photos here: http://www.secretprojects.co.uk/forum/index.php/topic,3712.0/all.html

Back to the Cheyenne - much as I hate leaving the Blackhawk - and I may ditch any A2A weapons, I don't want to go crazy and make an overpowered ubercopter! Hopefully I can steal some bench time with it this weekend or after work. I'm thinking a pylon with triple 70mm pods on the inner stations and a quartet of Hellfires on the outer.

I've done a (lengthy) backstory covering Cheyenne service and development from a late point in the real story, including a jet-assisted compound I'd love to build....just need more kits....

[KiwiZac]

As there won't be any model photos until late in the weekend (my future brother-in-law is being admitted to the Bar and we're invited), here's the aforementioned backstory...or, at least, the first half.

***

In 1971, political friction increased between the Army and the Air Force over the close air support (CAS) mission. The Air Force asserted that the Cheyenne would infringe on the Air Force's CAS mission in support of the Army, which had been mandated with the Key West Agreement of 1948. The Department of Defense (DOD) conducted a study that concluded that Air Force's A-X program, the Marine Corps' Harrier, and the Cheyenne were significantly different that they did not constitute a duplication of capabilities. On 22 October 1971, the Senate Armed Services subcommittee on Tactical Air Power conducted hearings to evaluate the CAS mission and the pending programs.

The most positive testimony for the Army's program came from the commander of the Air Force's Tactical Air Command, General William W. Momyer. In a surprising about-face, he cited helicopter casualty statistics of Operation Lam Son 719 as evidence such craft were vital and conceded Army aircraft with Army crews were the best solution. He also suggested helicopters (specifically calling out the Cheyenne by name) as being preferable for such a role over proposed fixed-wing types, which should remain with the USAF.

The Army convened a special task force under General Marks in January 1972 to reevaluate the requirements for an attack helicopter. The purpose of the Marks Board was to develop an "updated and defensible" material needs document. The task force conducted flight evaluations of the AH-56, along with two industry alternatives for comparison: the Bell 309 King Cobra and Sikorsky S-67 Blackhawk. The Army conducted a competitive fly-off of the helicopters from the spring 1972 until that July. Analysis of the three helicopters determined that while the Bell helicopter could not fulfill the Army's requirements the Sikorsky (as an armed transport) and Lockheed (pure attack) types should be ordered as they exceeded them. A contract was awarded to produce the Sikorsky as the AH-3G Mojave however no such order for the Cheyenne was forthcoming.

The Army also conducted a weapons demonstration for the Senate Armed Services Committee in early 1972, to show off the Cheyenne's firepower and garner support for attack helicopter development. Cheyenne #7 was chosen for the demonstration due to its use of the AMCS and it did not disappoint, showing an accuracy of close to 90% during its weapons demonstration. In April 1972, the Senate published its report on CAS. The report recommended funding of the Air Force's A-X program (which would become the A-10 Thunderbolt II), limited procurement of the Northrop/Hawker Harrier for the Marine Corps and, most explosively, full reinstatement of the Cheyenne production programme for the Army.

AH-56B and production
The unanimous positive reaction shown at the SASC demo and in the resultant report led General Marks, on 9 August, to announce the placement of an order for 450 improved AH-56Bs – considerably more than the original cancelled order of 1968. Although four years had elapsed Lockheed had retained the production tooling and jigs for the Cheyenne, and these were swiftly modified to suit series manufacture of the AH-56B. In the interim, six of the eight surviving AH-56A prototypes were modified to full B-model configuration for pre-production tests and familiarization.

The AH-56B incorporated the ICS and AMCS control improvements previously tested and proved on prototypes #7 and #9. Further testing by Army pilots throughout August and September 1972 showed the improvements removed the remaining control problems, improved stability, improved handling, and decreased the pilot workload. With the AMCS, the AH-56B routinely reached a speed of 247mph in level flight and in a dive #7 achieved 282mph; both B-models also demonstrated improved maneuverability at high speeds. The computer and sensor package benefited from the time delay between cancellation and production, being entirely replaced and refurbished with more powerful units including all-weather/day-night equipment, silencing the last critics of the type.

In January 1973 the Army accepted the first five new-build AH-56Bs and the process of service introduction began. By year's end half of the Army's AH-1Gs had been retired from active duty and replaced by Cheyennes. Before the US military withdrawal from Vietnam the type had proved itself, achieving unparalleled success in combat without loss including a spectacular action north of Saigon on the night of 21/22 January 1974. In September 1975 the final batch of Cheyennes were accepted into service, at which point it became the only pure attack helicopter in the Army's active inventory (the remaining Cobras having been passed to National Guard units).

YAH-56C and records
During 1976 Cheyenne #7 was taken from the Lockheed test fleet and taken over by the company's Special Projects Division. In a repeat of the XH-51A programme some 12 years before the aircraft was designated YAH-56C and was allocated to the Tri-Service Helicopter Speed Programme, designed to push the aircraft to the limits of helicopter speed.

A podded Pratt & Whitney J60 jet engine was fitted on each wing where the inboard weapons pylon had been located, aerodynamic refinements were made to the T-64's intakes and exhaust outlet, and the ventral tail fin was extended to include full covers for the tailwheel. The other weapons pylons and mounts, as well as the turrets and sensors, were removed. The large bubble canopy was replaced with a cut-down example designed to reduce glare and distortion, and to increase speed, eliminating the "hump-backed" appearance of in-service models.

After a series of hover tests the YAH-56C first flew on 6 August 1976 on rotor power alone, the first in-flight tests with the jets being undertaken in September. On September 10 the aircraft exceeded 255mph in level flight without jet assistance, the following day it flew at 260mph using the jets. The aircraft soon gained the moniker "Speedy C" among Lockheed and TSHSP staff, the name being painted on the helicopter's nose.

Throughout 1977 and 1978 the YAH-56C continued to push the Absolute Helicopter Speed Record, culminating in level flight top speeds of 261mph (helicopter) and 302.5mph (jet). However because of the pusher prop the helicopter record was not made official by the Federation Aeronautique Internationale, but a Compound category (E-4) was created and the Speed Cheyenne was recorded as the inaugural (and to date only) holder of all its speed records.

TBC....

[Captain Canada]

Nice read Zac !

[KiwiZac]

O Captain! You're too kind. Just for you, here's the rest:

***

AHU/ASH and AH-56D
Late in 1978 consultation took place between Lockheed and the Army to discuss the need for an updated Cheyenne in concert with an OH-58 replacement. The resulting Attack Helicopter Update (AHU) Programme, officially mandated and launched in February the following year, outlined the need to create an AH-56D model incorporating the latest technology in weapons, sensors and other systems to field from 1982 alongside the Advanced Scout Helicopter (ASH).

The Army specified a wide range of improvements to the AH-56B which were incorporated by Lockheed into prototype #9. One of the more visible changes in the D-model was the introduction of a flat-panel canopy based on that of the YAH-56C. An M297 20mm rotary cannon replaced the XM196 minigun in the nose and provision was made for the AGM-114 Hellfire anti-tank missile to be quad-mounted on the wing pylons (replacing the wire-guided BGM-71). The antiquated FFA rockets and pods were also replaced with an improved Hydra 2.75in rocket in 19-shot pods. Further updated and miniaturised computers replaced those of the B-model, the reduced weight allowing further crew armour to be installed, and infra-red suppression exhausts were fitted in place of the original single exhaust.

Prototype #9, now redesignated YAH-56D by the Army, took flight once more in September 1979 and was subjected to grueling test and evaluation at the Yuma Proving Ground. A production AH-56B which was extensively damaged in a landing accident, s/n 74-15814, was purchased back from the Army by Lockheed and became the second YAH-56D. This flew again on October 2 and soon joined its comrade at Yuma and by January 1980 the pair had flown more than 350 flight hours.

With the YAH-56D trials successful the Army signed a contract with Lockheed to upgrade half of the existing fleet to D-model configuration, and ordered a further 350 new-build AH-56Ds. Once they had been returned by the Army Lockheed retired the two YAH-56Ds: 74-15814 was retained for static testing and proof-of-concept work, and #9 was donated (along with the sole YAH-56C) to the Army Aviation Museum at Fort Rucker, AL, for display.

Delivery of the Cheyenne D began in February 1981, followed shortly after by introduction of the Hughes OH-6F (winner of the ASH competition).

H-56E/F and LHX
The 1980s brought overseas orders of D-model Cheyennes – 150 in total – as well as Lockheed's own development of a further-improved AH-56E. However by the time the E-model mockup was ready (in spring 1984) the Army was looking at a new programme, the Light Helicopter Experimental (LHX). This was to comprise two distinct models with several shared systems: the Scout/Attack (SCAT) and the Utility (UTIL). With the LHX requirements focused on a lighter, stealthy helicopter Lockheed stripped down the mockup AH-65E to start from scratch on both facets of the competition.

As well as Lockheed's as-yet unfinished H-56E several other companies lodged their proposals, chief among them teams of Boeing-Sikorsky and Bell-Hughes. Unsurprisingly the three teams played to proven design strengths, which for the H-56E meant retaining the push prop and rigid rotor system. Removing the weapons created room for a passenger cabin in the H-56F UTIL, which also had its cockpit reconfigured to a side-by-side arrangement, whereas the H-56E SCAT had a smaller rotor diameter and shortened tailboom. The vertical stabiliser arrangement was also drastically changed for both models, the ventral fin being replaced by a dorsal on top of the boom. The tailwheel, now located directly on the boom, was fully retractable.

By mid-1985 the H-56 LHX was being considered by the Army alongside the other leading proposals, now only for the SCAT due to weight issues with the UTIL, however Lockheed lost out to Boeing-Sikorsky and Bell-Hughes (later Hughes alone, ultimate winner of the contract). The programme wasn't seen as a loss by Lockheed staff and management as independent progress continued on prototypes of each – the RAH-56E, to be marketed to the USMC and foreign air forces for the attack role, and the UH-70 (formerly the H-56F) light troop transport and utility helicopter, marketed as a UH-1 replacement. The UH-70 – covered in-depth elsewhere – lost its pusher prop to become a more conventional helicopter whereas the RAH-56E remained unchanged from the LHX-SCAT proposal.

The RAH-56E prototype first flew in early 1988 at Van Nuys and the test crews reported positive results in all flight regimes. A second example was close to completion when, on June 6, the first suffered sudden vibrations at low level and crashed, killing both the pilot (Lt Col Rob Halliday) and the observer/gunner (Lockheed's Allan Parker). All work on the RAH-56E programme was immediately halted while the accident was investigated.

After six months the fault was found to be manifold – several components in the E-model rotor drive system were found to be faulty and failed in quick succession, resulting in a catastrophic failure. Despite the efforts of Lockheed engineers the issues could not be fixed and, with no prospect of sales in sight, the RAH-56E programme was cancelled and the unfinished second prototype scrapped.

Retirement
In 1990 the US Army began to phase out its Cheyenne fleet in favour of more Hughes RAH-69 Navajo – the winning LHX design – and sold 75 AH-56Ds to Israel, these also being replaced by the Navajo in 2000. There was speculation the type would see service during Operation Desert Storm but the Army's preference was for the Navajo to be deployed, so the Cheyenne wind-down continued regardless. By 1993 the last army unit with Cheyennes had converted to the Navajo and its old machines were flown to long-term storage in Arizona.

However it was not the end of the type's US service as several airframes were transferred to the National Guard, once more replacing the aged AH-1 Cobra. It wasn't until September 2008 that the final NG Cheyennes were retired and placed on museum display, ending the type's 44-year-long military service.

[Captain Canada]

I was so close to the museum at Fort Rucker and forgot all about it ! I'll be sure to hit it next time   

Another nice one Zac. I'd love to see every variant mentioned.....but I'll settle for the one you're building now, For now. 

[jsport]

cheyennes rule and rock 

[KiwiZac]

Paint and decals finished! Just need to mount the weapons.

[Captain Canada]

Very nice Zac ! Such a sleek looking machine...going to look great on the shelf !

[jsport]

lookin fly for sure.

[KiwiZac]

Flyer and jsport - you're too kind!

Cap'n - indeed...if only I had the shelf space! That's going to be my next task..well, at some point. It's been a great kit to build, no fit issues, ripe for scratch detailing. I also need to do an anti-IR exhaust, maybe just a pointy-uppy one. And to scratch pylons for the Hellfires. And take better photos!

[DaveyBoy]

You have  do a Great job with this  , I remember this kit well in fact I've got 1 knocking around the house some where... you have given me thought of finding it and redoing it up. 

[DogfighterZen]

  Wicked machine! Beautiful! 

[Captain Canada]

Oh yeah....love it !