westland and the attack helicopter from lynx to apache

Journal of Aeronautical History Paper 2020/05

129

Westland and the Attack Helicopter – from Lynx to Apache

Dr R V Smith, FRAeS; J P Graham, FRAeS

ABSTRACT

In July 1995, Britain selected the AH-64D Apache as the Attack Helicopter for the Army Air

Corps. Prior to this, there had been sustained activity, involving Westland Helicopters Ltd

(WHL), the Royal Aircraft Establishment (RAE)/Defence Experimental & Research Agency

(DERA), Defence Science & Technology Laboratory (DSTL), Future Systems (Rotary Wing)

(FS(RW)) and MoD Operational Requirements (OR) staff, to examine UK options for the

provision of national and international collaborative attack helicopter solutions.

Much of that work has never been reviewed publicly and, despite not resulting in a successful

product, the solutions examined contained innovative technologies and design approaches. Some

of these features are only now emerging in programmes elsewhere, such as the American Future

Attack Reconnaissance Aircraft (FARA) programme.

This paper examines these projects, from Armed Escort Lynx and P277 through to Westland

WG.47, summarising their origins, requirements and underlying technologies, to record the

efforts, mainly conducted by the Future Projects and Advanced Technology Departments within

Westland Helicopters Ltd.

List of Abbreviations

Abbreviation Definition

AAWWS Airborne Adverse Weather Weapon System (AH-64)

ABC Advancing Blade Concept – a Sikorsky concept for a co-axial lift-offset rotor

ACGS(OR) Assistant Chief of General Staff (Operational Requirements)

ACSR Active Control of Structural Response

ACT Active Control Technology

AEG Advanced Engineering Gearbox

ADATS Air Defense Anti-Tank System (missile)

AFCS Automatic Flight Control System

agl Above ground level

ALAT Aviation Légère de l'Armée de Terre (French Army Light Aviation)

AM Amplitude Modulation

AMI Aeronautica Militare Italiana (Italian Air Force)

AVSRAG Air Vehicle Signature Reduction Advisory Group

AUM All-Up Mass

AUW All Up Weight

AW Agusta Westland

BERP British Experimental Rotor Programme

BHC British Hovercraft Corporation


130

BTS Battalion Targeting System

CAA Civil Aviation Authority

CADMID Defence Life Cycle comprising: Concept – Assessment – Development –

Manufacture – In Service - Disposal

CSAR Combat Search and Rescue

DAS Defensive Aids Suite

DCF Discounted Cost Financing

DERA Defence Experimental & Research Agency

DE&S Defence Equipment & Support

Dstl Defence Science & Technology Laboratories

EMC Electromagnetic Compatibility

EMDG Euromissile Dynamics Group (developer of the Trigat missile system).

FAHSG Future Army Helicopter Steering Group

FARA Future Attack Reconnaissance Aircraft

FBL Fly-by-light

FBW Fly-by-wire

FCDS Feasibility & Cost Definition Study (for A129 LAH)

FFR Folding-Fin Rockets

FINABEL European organisation promoting collaboration and interoperability of member

nations’ Land / Army equipment (originally from initials of founding member

states)

FM Frequency Modulation

FPDS Feasibility & Pre-Definition Study (for NH90)

FS (RW) MoD customer for Feasibility Studies (Future Systems (Rotary Wing))

FVL Future Vertical Lift (US Army program)

GAO Government Accountability Office (US)

GECAL 50 Multi-barrel heavy machine gun (originally developed by General Electric)

GSOR General Staff Operational Requirement

GSR General Staff Requirement

GST General Staff Target

HAC3G Hélicoptère Anti Char 3rd Generation

HF High Frequency

HHC Higher Harmonic Control

IHADS Integrated Helmet and Display System (A129)

ISA International Standard Atmosphere

ISD In Service Date

LAH Light Attack Helicopter

LCH Light Combat Helicopter

LHX US Scout helicopter programme later to lead to RAH-66 Comanche

LHTEC Light Helicopter Turbine Engine Company (Manufacturer of the T800 engine)

LO Low Observable (signatures)

LR Long-Range (TRIGAT)

LRU Line Replaceable Unit

LSDW Laser Sensor Damage Weapons

LTC Long-Term Costings

MALT Military Advisory Liaison Team (Westland)

MBB Messerschmitt-Bölkow-Blohm


131

MDHC McDonnell Douglas Helicopter Corporation

MG Machine Gun

MMH/FH Maintenance Man Hours per Flying Hour

MMS Mast Mounted Sight

MoD Ministry of Defence

MoD(PE) Ministry of Defence (Procurement Executive)

MoS Ministry of Supply

MOU Memorandum of Understanding

MSIP Multi-Stage Improvement Plan (AH-64A)

MTBMF Mean Time Between Mission Failures

MTOW Maximum Take-Off Weight

NEMP Nuclear electro-magnetic pulse

NNEMP Non-nuclear electro-magnetic pulse

NOE Nap-of-the-Earth

NVG Night Vision Goggles

PAH-2 Panzer Abwehr Hubschrauber (Anti-Tank Helicopter) - 2

OEI One Engine Inoperative

OGE Out of Ground Effect

OR Operations Research

PD Product Development

PNVS Pilot’s Night Vision System (AH-64)

PV Private Venture

R&D Research and Development

RAE Royal Aircraft Establishment (Customer for most pre-feasibility and technology

studies)

RAM Radar Absorbent Material

RAM-D Reliability, Availability, Maintainability - Durability

RCS Radar Cross-Section

RF Radio Frequency (Hellfire)

RN Royal Navy

RPH Remotely Piloted Helicopter

RR Rolls-Royce

RARDE Royal Armament Research & Development Establishment

RDAF Royal Danish Air Force

RSRE Royal Signals & Radar Establishment

RTM Rolls Turbomeca (engine manufacturer)

SACLOS Semi-Active Command to Line Of Sight

SAR Search and Rescue

SARO Saunders-Roe Ltd

SSB Single Side Band

TADS Target Acquisition and Designation System (AH-64)

TI Thermal Imagery

TNA The National Archives

TOW Tube-launched, Optically-tracked, Wire-guided anti-armour missile

UHF Ultra High Frequency

VFW Vereinigte Flugtechnische Werke (VFW)

VNO Maximum normal operating speed


132

VNE Never exceed speed

VHF Very High Frequency

WHL Westland Helicopters Ltd

WP Warsaw Pact

INTRODUCTION

The UK’s operational experience of anti-armour helicopter operations is largely restricted to the

Westland-designed Lynx AH.1 and AH.7 and the McDonnell Douglas (latterly Boeing) WAH-

64D Apache, assembled in Yeovil. This bald statement leaves the impression that, other than the

Lynx, Westland Helicopters Ltd has not done any significant work on the technology or design of

attack helicopters, following on from the design and development of the Lynx.

This paper sets out to correct that impression. It establishes the scene by describing the origins

and procurement of Lynx and contemporary proposals for its development in attack roles. This is

followed by a review of a series of advanced attack helicopter studies, developed to differing

levels of maturity, from the late 1970s, through to the early 1990s. These studies were largely

driven by the evolving requirement for an attack helicopter to survive in the face of developing

sophisticated threats and, among other features, had a common thread of the reduction of

detectable signatures.

Little has been previously published about these designs, but they variously incorporated several

features that were novel at the time, some of which are now emerging on other companies’

projects.

Figure 1. Westland WG.47: A design drawing upon experience from unmanned

helicopters, and the WHL Advanced Engineering and Advanced Technology research

programme.


133

The paper discusses the attack helicopter work carried out in the context of WHL’s approach to

the generation of future projects, its development of advanced technology and the relationship of

these studies to the contemporary MoD acquisition processes and organisations.

Finally, reference is made to developments elsewhere which were to some degree anticipated by

the studies conducted at Westland Helicopters Ltd.

2. ORGANISATIONAL ASPECTS

To provide context for the rest of this paper, this section briefly comments on the contemporary

MoD study and procurement processes and the organisational arrangements within Westland

relating to the development of new projects.

The primary context for this discussion is the period following the rationalisation of the

helicopter industry that took place in 1960. Up to this point, Westland’s product range was

dominated by the licence production (and development) of products originally designed by

Sikorsky Aircraft in the United States.

Following this rationalisation (Figure 2), Westland absorbed the helicopter interests of the Bristol

Aeroplane Co Ltd, Fairey Aviation Ltd and Saunders-Roe Aircraft Ltd (SARO). During the early

helicopter years, MoD policy excluded Westland from the receipt of UK rotorcraft research and

development funding, as Westland’s rotorcraft technology was initially perceived as solely

comprising that transferred from Sikorsky (1).

Figure 2. Britain’s Rotorcraft Industry


134

2.1 UK Procurement Process

The current MoD acquisition process is known as CADMID, an acronym relating to the project

life cycle: Concept – Assessment – Development – Manufacture – In-service – Disposal.

The understanding of the likely operational performance, technologies, cost, timescales and key

risks (and their mitigations) of likely conceptual design approaches is dealt with in the Concept

phase. In parallel, the Operational Requirements staff will be developing a set of User

Requirements. The studies required to clarify and quantify these aspects are contracted directly

with organisations that are perceived as possessing the required skills and technologies.

The body of knowledge thus generated allows the MoD Procurement organisation to determine

its procurement strategy and to evolve the User Requirements into a set of solution-agnostic

System Requirements that allow a (normally) competitive Assessment Phase to be launched.

Assessment of the bids received results in the down-select of a winner that will receive a contract

for the Development phase to generate equipment meeting an agreed Specification. In the 1970s

through to the 1990s this terminology did not exist, although a similar set of activities took place

under different titles, known as the Downey cycle (Figure 3).

Under the Downey regime, the assessment of options in terms of technology and design concept

was typically contracted by the RAE Helicopter Division of Structures Department (later

Materials and Structures Department) using research funds from their Corporate Research budget.

These studies were typically managed by Alan Jones (Superintendent of Helicopter Division)

acting as customer.

Figure 3. Comparison of DOWNEY and CADMID procurement cycles; the DOWNEY

cycle terminology is applicable to most of the activities described herein.


135

As requirements became clearer, Pre-Feasibility studies would be let to understand the capability

of specific concepts against an emerging requirement. These contracts would probably be placed

by the FS(RW) (Future Systems (Rotary Wing)) area of MoD and would typically be conducted

against a Draft Staff Target. The lead customer for much of this activity at this time was Ian

Barrett (and later Tim Cansdale).

The next life-cycle stage at this time would be Feasibility or Pre-Definition where the effort was

directed at establishing the capability, timescales, risk and cost against a more closely defined

Staff Target. A successful outcome would allow a Staff Requirement to be drawn-up to allow a

Project Definition Study to be completed. This would lead to a Full Development programme

against a Specification and associated costs and timescales. Successful Development would lead

to a Production phase.

2.2 Westland Technology and Project Organisations

The merger of the major helicopter industrial interests in the UK under the ownership of

Westland Aircraft Ltd served to combine the undoubted design skills of Bristol, Fairey and

SARO (ex Cierva) with the production experience available at Yeovil.

Under the guidance of O L L Fitzwilliams, the Yeovil based helicopter engineering team had

become proficient at modifying baseline Sikorsky designs to better suit Customer needs and had a

well-established production support organisation. Not until after the merger were the skills and

resources sufficient to realistically launch new aircraft design. The arrival from Bristol of Raoul

Hafner as the Director of Research and Reginald Austin as the Head of the Project Office allowed

substantive work to be undertaken at Yeovil on ab initio designs. It is not surprising that the

initial studies and proposals owed much to earlier work undertaken under Hafner’s guidance and

Ministry of Supply (MoS) sponsorship at Bristol.

During the latter half of the 1960s the Project Office was supplemented by a team in mainstream

Engineering reporting to John Speechley which was directed towards tilt-rotor studies and the

design of a demonstrator tilt-rotor aircraft, WE.01. This arrangement was later refined such that

the engineering-led group dealt with studies closely derived from current products leaving the

Project Office led by Hafner to be responsible for future designs and concepts. By the early

1970s these groups were managed by David Howell, Alan Waddington and R J (John) Jupe.

A separate organisation was created from mid-1970 onwards to conduct the design and

development of remotely piloted helicopters (RPH), led initially by Reg Austin and David

Wright.

In October 1980 a major reorganisation of the technical staff established ”Advanced

Engineering”, headed by D E H (David) Balmford, to combine technology development and

future project activities. Figure 4 shows the organisation and capabilities of this team, as it had

evolved by 1984 (that is, contemporary with the Attack Helicopter activities discussed in Sections

7 to 12, below).


136

Figure 4. Westland Advanced Engineering Organisation and its Capabilities (1984)


137

Reporting to Balmford were Mr P N (Phil) Goddard as the “Head of Advanced Technology”, and

Dr R V (Ron) Smith as “Chief Project Engineer (Advanced Projects)”. The Advanced

Technology team headed by Goddard was organised into a number of areas by specialisation,

notably Avionic & Mission Systems under M (Mike) Pengelly and Vehicle Technology under

GM (Geoff) Venn. The Advanced Projects team was capable of all aspects of Preliminary

Design, with an emerging Design Synthesis capability.

With the RAE Corporate and Applied Research budgets beginning to be focused on the needs of

a specialist attack helicopter, the merging of all the Company’s research and future product

development was to prove a timely step. In response to the Army’s conviction that the helicopter

provided a basis for a highly effective anti-armour weapon system, the RAE focus at this time

was on the design of small, robust, and nimble rotorcraft using the latest technology, configured

to operate in a demanding threat environment. This led to the future project being variously

referred to as either the Light Combat Helicopter (LCH) or Light Attack Helicopter (LAH).

The WHL Advanced Technology department covered a wide range of specialisations, including

the management of technology demonstration programmes, transmission design, digital system

architectures, human factors, advanced sensors, novel flight control design and survivability in

high threat environments. This resulted in close working relationships with parallel RAE

Departments and a coherent programme of work between Industry and customer participants,

whether from MoD, RAE or the User community.

The new Future Projects department was initially focused on examining options for the further

development of the WG30 helicopter, but soon became involved in Attack Helicopter activities,

as discussed below in Sections 9 - 13. The Technology and Future Projects activities within

Advanced Engineering collectively possessed all the skills and techniques required to meet the

challenge of the preliminary design and performance assessment of future combat rotorcraft.


138

3. THE BACKGROUND TO LYNX

3.1 Early Beginnings

The origin of Westland’s work on the dedicated armed attack helicopter can be traced to studies

first undertaken by the WHL Future Projects team under Austin during 1962 to explore the

configuration of a 3,630 kg (8,000 lb) maximum take-off weight (MTOW) tactical utility

helicopter for the Army Air Corps sized to transport a troop squad. A variety of options were

proposed and these were used to solicit User comment and support for such a concept. This

aircraft was, from the outset, conceived as having the potential to be armed with a range of air to

ground weapons. A key aspect was that a common airframe was to be used, equipped as required

with role equipment.

Following discussion with the User community, the definitive WG.3C(2) exhibited a substantial

increase in take-off weight, a pair of de Havilland Gnome engines mounted forward of the rotor

head and a cabin enlarged to accommodate up to 15 passengers plus two crew. Both the low-

profile gearbox, using conformal gear forms, and the flexible element rotor head were close

analogues for design solutions adopted later by the production Lynx helicopter.

Though well received at the time, the User community requested that a further stretch be

implemented but the Company reaction was that such a move would place the design too close to

on-going WS-58 “Wessex” replacement proposals and at this point all work on the WG.3 ceased.

However, Austin’s team now returned to the original concept of a squad carrier and a new

designation was adopted, WG.13, to clearly differentiate it from the earlier WG.3 series of

studies. The WG.3 design was, therefore, the true progenitor of the Lynx.

Figure 5. Westland WG3 layout as proposed in October 1963.


139

3.2 WG.13

A draft General Staff Operational Requirement GSOR 3355 (3) was made available in October of

1964 calling for an in-service date of 1972: no reference was made to an anti-armour role but the

aircraft was required to mount “offensive and defensive” armament.

Probably resulting from progress in the USA with a dedicated armed derivative of the UH-1 both

the Company and the Army agreed to consider an “armed escort” derivative, although the

operational requirements were very vague: a maximum speed of 333 km/hr (180 kt) and a

payload of 1,133 kg (2,500 lb) of weapons and armour differentiated this derivative from the

squad carrier baseline. Trade studies completed in 1966 demonstrated conclusively that the

armed escort role could not be satisfied by a role-equipped tactical transport airframe without

significant compromise: at this time the concept of a dedicated airframe sharing common

dynamic components, engines and aircraft systems was developed as the WG.13R variant (4)

following the “Q” variant that described the tactical transport aircraft (Figure 6).

Assumptions made with respect to the arming of the “R” variant remained tentative, with the

Nord Aviation SS-11 and AS-12 missiles used as convenient examples.

WG.13R represents the first comprehensively studied expression of a dedicated armed escort

helicopter developed in the UK. It was to inform the following Anglo/French Lynx program as

well as all subsequent Lynx based attack helicopter proposals.

3.3 The Lynx programme

During 1966 the Royal Navy (RN) took a formal interest in the WG.13 project and a Joint Service

Requirement was issued in June 1966 but the formal Anglo/French helicopter programme did not

yet encompass WG.13 in any guise. The French Army Air Corps (ALAT) were operating

“Alouette” in an armed ground attack role using SS-11; the first such use of a helicopter.

An informal exposition of the operational requirements for a future armed reconnaissance

helicopter were tabled by Sud Aviation during a meeting with WHL and the UK MoD in

Figure 6. The Westland WG.13R was the first dedicated armed escort helicopter

schemed in the UK.


140

Marignane in March of 1966 (5). An all up weight of 2,500 kg (5,512 lb), speed of 350 km/hr

(189 knots), a crew of three and a weapon load combining SS11 and a 20 mm cannon provided

an outline of the envisioned aircraft.

Up to this time all studies of an armed attack derivative of WG.13 had been conducted at Yeovil

with reference only to indicative UK requirements and possibly by reference to the Bell Model

D209 which had flown in 1965.

The WG.13R appeared to offer a credible option to satisfy the anticipated ALAT requirement for

an armed reconnaissance helicopter but was quickly modified to incorporate a three-man cockpit

configuration. Once the WG.13 element of the Anglo/French helicopter programme had been

firmly established, programme updates included this variant as a matter of course although its

configuration was initially tentative because of the late availability of a formal ALAT

requirement.

Interestingly, despite the initial support for the Armed Escort version the formal UK requirements

were only to equip the army utility variant with an unspecified anti-armour weapon at a future

date. (6)

With the armed escort version firmly part of the Anglo/French programme detailed design

commenced. As for the other variants, aircraft definition transferred from the Future Projects

team to the mainstream engineering departments with Tadeusz (Ted) Ciastula assigned as the

Chief Designer. All variants were to share common engines, rotors and transmissions along with

common services and flying controls.


141

4. Proposed Armed Escort Lynx, “Wildcat”, P277 and WG37 “Warrior”

4.1 Armed Escort Lynx

The starting position for this variant as published by Austin would have been equipped with

retractable weapons and undercarriage, plus lift compounding via small wings, features which

What would emerge under the guidance of Ciastula as the WG.13T-008 (7) would be largely

conventional: the anti-armour weapon would be externally mounted on stub carriers offering no

inherent lift compounding benefit though the undercarriage would still be retractable. The anti-

armour weapon would have been the Bölkow/Nord HOT missile supplemented by a turret-

mounted 20 mm cannon fitted below the cockpit. The gunner’s station was mounted on a

turntable which rotated as the cannon was slewed to maintain the gunner’s relationship to the

direction of fire, an arrangement also adopted on the Lockheed AH-56 Cheyenne.

During 1968 the configuration was significantly modified with a return to a two-seat tandem

cockpit layout. A presentation to Panel 10 of the NATO Armaments Group in March 1969

indicated an acceptance that the weapon load-out would be role specific. Anti-tank weapons

were now described as optionally HOT, “Swingfire”, SS11 and AS12. A full-scale mock-up was

constructed at this time and transported to Sud Aviation at Marignane but for what purpose

remains unclear (it was later to be repatriated and used in support of variant development at

Yeovil).

Figure 7. Illustrative schemes for the WG13T Armed Reconnaissance variant, including

early internal arrangement drawing (from Ref 6).


142

In October of 1969 the French Government declared that the ALAT requirement for an Armed

Escort variant was to be cancelled with immediate effect due to budget constraints: all formal

work on this variant ceased with immediate effect.

The UK Army Air Corps had already planned to dual role the Utility Variant in the anti-armour

role and would go on to develop the Lynx to carry both offensive and defensive armament.

Equipped with a roof-mounted sight and carrying eight Hughes TOW missiles it replaced the

Scout/SS11 combination in this role and maintained the capability through several updates until

the arrival of WAH-64 “Apache”.

4.2 “Wildcat”

With the Lynx programme in full scale development, and no formal Customer requirement, there

was little enthusiasm to continue to work on an Armed Escort derivative. However, as the

production aircraft design matured, the Future Projects group once more turned its attention to a

two seat, tandem-configured dedicated attack variant.(9)

Maintaining the principle of maximum practicable commonality and using the very latest

definition of the WG.13, together with a growing understanding of modern anti-armour weapon

systems, a configuration emerged in 1973 known internally as “Wildcat”. This aircraft would

have a maximum take-off weight of 4,300 kg (9,500 lb) and carry both an area suppression

weapon (a 20 mm cannon) and up to eight modern anti-armour missiles (either the Aerospatiale

HOT or the Hughes Aircraft Tube-launched, Optically-tracked, Wire-guided anti-armour missile

(TOW)) (Figure 8).

The weapon system sight would be nose mounted, placing the gunner in the front seat of the

tandem cockpit. In most respects this aircraft was closely derived from the cancelled Armed

Escort variant and was similar to the Bell AH-1 operated by the US Army but with the added

benefit of twin-engine safety. In 1973 the Westland vision for an anti-armour attack helicopter

mirrored proposals made by Bell to equip AH-1 “Cobra” with TOW which would be realised

with the AH-1Q, first fielded by the US Army in 1975.

It remains unclear if the “Wildcat” configuration was formally submitted to the MoD or the

Operator community but a detailed report was prepared describing the work completed and

providing convincing estimates of weight and performance.


143

In February 1975 Major General Farrah Hockley, then the Director Combat Development (Army)

visited the Yeovil factory and was presented with the Company’s vision for future helicopter

developments (10).

Amongst these concepts was an Armed Attack Helicopter based on commonality with the Lynx

AH.1 but having a narrow tandem configured, two-seat, fuselage. Its maximum take-off weight

would be 4,300 kg (9,480 lb) and it would be equipped with a pair of developed RR Gem

engines. This aircraft was the “Wildcat” of 1973, except that it had now been drawn with slab

sided canopies as necessary to suppress the sun glint signature that was prevalent with a curved

canopy (Figure 9). By June of 1975 a marketing brochure had been prepared and was distributed

to selected potential Customers (11).

Figure 8. Westland WG.13 Mk.2 armed attack Lynx (Wildcat)


144

4.3 Westland-VFW Fokker P277

P277 followed from 1976 and was the identity assigned to the armed attack helicopter project

collaboration between Westland and VFW-Fokker that was publicly announced in 1977 and

which took as its baseline the Yeovil Future Project team’s “Wildcat” configuration. The aircraft

was aimed at the emerging German army requirement for a second generation “Panzer Abwehr

Hubschrauber” (PAH-2) to follow on the interim MBB BO105 based PAH-1. Extensive wind

tunnel tests were completed for the first time on this configuration at the VFW-Fokker facility in

Bremen.(12)

A full-size mock-up was built by VFW-Fokker along with a human factors cockpit test facility.

The only major change to the “Wildcat” configuration presented in 1975 was a further engine

upgrade to the Gem 4 standard and an increase in maximum take-off weight to 4,760 kg (10,500

lb). During the detailed definition of this aircraft its canopy would once more be modified to a

“stepped” arrangement, offering the pilot a much-improved view forwards in poor weather and

also minimising the mass of armour separating the two cockpit stations (Figure 10).

The formal German PAH 2 requirement, thought imminent in 1977, was not actually formally

issued until 1983, by which time the acquisition of VFW-Fokker by Messerschmitt-Bölkow-

Blohm (MBB) in 1981, combined with the political desire for a Franco/German collaboration

ruled out any possibility of the P277 being taken any further.

Figure 9. Advanced Attack Lynx as briefed to Maj Gen A.H. Farrar-Hockley


145

4.4 “Warrior”

All substantive work on a dedicated two seat armed attack variant of Lynx now ceased but the

Future Projects group maintained a close relationship with the Operator through the auspices of

the Military Advisory Liaison Team (MALT) based at Yeovil and staffed by Colonels Moss and

Waddy, both retired.

Through this relationship the Company remained convinced that the Operators’ desires for an

effective anti-armour weapon system would eventually result in a resurgence in UK interest in

this class of vehicle. The P277 was a solution that could be implemented quickly and at the

lowest possible cost but it did not offer a transformation of capability that was seen in some

quarters as necessary to combat the Warsaw Pact (WP) threat to NATO. This desire was later to

be carried through in large part to the flight performance requirements sought in the Light Attack

Helicopter Staff Target GST3971, which is discussed further in Section 8.2.

A 1979 presentation to Major General Ian Baker of ACGS(OR) was intended to focus on a range

of concepts that might realise significant commonality across a wide range of airframe types

appropriate to all battlefield uses of rotorcraft.(13) The context was the extant “Pathfinder” R & D

program that was envisioned as the route to fielding advanced technology for the rotors,

transmission, and structures.

Alongside these ideas the Company presented its vision for a revolutionary combat rotorcraft by

way of an example of the technological consequences of fielding significantly increased speed,

agility and survivability. This was project WG.37 Advanced Combat Helicopter, aka “Warrior”

in Project Office parlance, which had resulted from studies of high-speed rotorcraft

configurations and technology, previously completed under the sponsorship of the RAE materials

and Structures Department. “Warrior” was configured with a co-axial lift offset rotor having

Figure 10. P-277 schemes including stepped cockpit variant and full-size mock-up.


146

both thrust and lift compounding. In some ways it mirrored the technology anticipated by the US

Army 2004 Future Vertical Lift (FVL) program and the subsequent Future Armed Reconnaissance

Aircraft (FARA) program initiated by the US Army during 2019 (Figure 11).

However, notwithstanding the launching of studies by the Army’s OR branch investigating future

helicopter needs, the formal Government position remained firm to the effect that no replacement

for AH-1 Lynx in any role would be required until the late 1990s. (14, 15)

The “Warrior” configuration was, perhaps justifiably, regarded as overly complex by GS(OR)14

Col Hickey: the stated OR staffs’ view was that future Army rotorcraft must be “simple, robust

and cheap, and must use up to date materials and structures” (16). Within 3 years the Light

Combat Helicopter programme and associated GST 3971 would introduce increasingly

demanding performance requirements leading to an inevitably complex and heavy solution, even

though the leap in vehicle performance offered by WG.37 was not featured as a requirement.

5. LYNX 3

Alongside the development of advanced concepts by the Future Projects Group the Lynx product

team set about designing a near term multi-role variant of the in-service Lynx. The “Lynx 3”

programme was led by Richard Case as Chief Designer but with day to day control assigned to

Derek McMullan (17). This was intended to provide a battlefield helicopter which could operate

Figure 11. Artist’s impression of the Westland Warrior proposal.


147

across a wide range of offensive, defensive and supporting battlefield roles. Its main features

were an enlarged cabin, improved performance, wheeled undercarriage, significantly increased

maximum weight and a comprehensive air to ground and air to air weapon capability. A naval

variant was also proposed (Figure 12).

During the early phase of detailed design, the aircraft was the subject of a formal proposal to the

Federal German Army to satisfy the PAH-2 requirement. (18)

The prototype (ZE477) flew for the first time on 14 June 1984, powered by two Rolls-Royce

Gem 60 engines of 835 kW (1.115 shp) normal rating for twin-engine operation. The prototype

flew with standard Lynx production rotor blades, although the intention was to fit the advanced

BERP III rotor blades to production aircraft, allowing a maximum take-off weight of 5,896 kg

(13,000 lb).

This was the final attempt to create an Armed Attack Helicopter derivative from the WG.13 Lynx

family with only one prototype built and flown, and with no MoD support, there were no sales.

The undercarriage configuration was later to be adopted for the Lynx AH Mk 9 (16 new-build

plus 8 conversions from Lynx AH.7).

6. REMOTELY PILOTED HELICOPTERS (RPH)

During 1968 the Future Project team began its assessment (20) of an unmanned rotary wing

battlefield observation system, a role assigned at that time to manned helicopters and the primary

combat support role envisaged for the planned “Gazelle” AH.1. Austin’s Future Projects team

had elected to consider how airborne battlefield surveillance might best be assured in a non-

Figure 12. The Westland Lynx 3 ZE477


148

permissive anti-air environment: their conclusion was that small, semi-disposable, unmanned

aircraft possessing an inherently low signature was the solution of choice.

The outcome was project WG.25, a 200 kg turbine powered co-axial rotorcraft having low optical

and noise signatures. Later refinements would add low radar cross section by virtue of a smooth

plan-symmetric shape and a novel control system having no preferred direction of flight such that

the data link antenna could be pointed using yaw control.

From around 1971, MoD sponsorship for studies of the concept of an unmanned rotary wing

target acquisition system included contracts with WHL and Canadair covering airframe aspects.

The Westland study was to derive a somewhat smaller air vehicle than envisaged by the WG.25

outcome as the required endurance and the likely mass of the electro-optic payload was further

refined. Air vehicle stabilisation and navigation to and from the on-task area was to be fully

automated. Following completion of this study activity a sub-scale model was built and flown to

demonstrate the resulting novel control requirement.

Later, contracts were received for a demonstrator (WR-06 “Wisp”) and a full scale quasi-

operational demonstrator (WR-07 “Wideye”) under the MoD project names of CONGA and

SUPERVISOR respectively (Figure 13).(21))

Under cover of these programmes an extensive investigation of radar cross section and engine

exhaust thermal signature management was launched. The plan-symmetric smooth external

shapes were augmented using radar absorbent materials (RAM) manufactured as semi-structural

items by Plessey (Towcester) and trials were executed in the UK Radar Cross Section (RCS)

measurement facility (Figure 14).

Figure 13. Westland experimental Remotely Piloted Helicopters (RPH)


149

As a direct result, further investigations of the effects of airframe shape and rotor blade

construction were undertaken and the WR-08 configuration with a conical plan-symmetric

airframe was both wind tunnel and radar range tested with mixed success: radar cross section was

markedly reduced without reliance on the use of RAM but unstable aerodynamic behaviour was

witnessed in the Westland wind tunnel.

No ready solution could be found to the poor aerodynamic behaviour and so the planned

production of SUPERVISOR system to meet GSR 3494 was to retain an air vehicle having a

smooth barrel shaped fuselage with structural RAM skin panels and retractable undercarriage.

Taken together these measures were determined to achieve a level of radar cross section judged

by Royal Signals & Radar Establishment/Royal Armament Research & Development

Establishment (RSRE/RARDE) as commensurate with appropriate levels of battlefield

survivability.(22)

Following the termination of the SUPERVISOR programme in late 1979 the Army OR staffs

remained true to the concept of unmanned aerial surveillance and launched a revised and

simplified operational requirement as GST 3846 under the programme title “PHOENIX” (Figure

15). The OR staffs expressed a desire that all parts of the system should exhibit low signatures,

but values were not prescribed.(23)

Industry was invited to comment and offer system solutions. Along with BAe, Ferranti and

Marconi, Westland was selected to complete funded PD activities with the intent that a down

select to two would then lead to a funded “fly-off”. The Westland bid, managed and submitted

by British Hovercraft Corporation (BHC), included a low signature air vehicle, being small in

size, having an extreme focus on shaping to minimise RCS and fully integrated, shielded and

silenced, hot exhaust management.

Figure 14. Signature reduction trials using Westland RPH designs – WR-07 with RAM and

wind tunnel tests of WR-08 with body shaping


150

Wind tunnel testing proved that the shape chosen was stable and exhibited low drag; radar range

testing demonstrated that the targets set by the SUPERVISOR programme had been met with

some margin. The Westland proposal was not selected for the fly-off programme which was

eventually won by GEC Marconi using a Flight Refuelling fixed wing air vehicle having no

obvious attention to signature reduction.

The Westland team were re-assigned in March 1983 to other programmes although would be re-

formed briefly in 1990 to support the delivery of flight ready hardware to Martin Marietta in

California for use in demonstration tests of the proposed Battalion Targeting System (BTS). The

concept developed by Martin Marietta was for a low signature, tethered, air vehicle mounting a

radar sensor. The helicopter rotor was to be co-axial and mounted on a plan symmetric conical

fuselage: Westland wind tunnel trials with this low radar cross section configuration pre-dated the

BTS by more than 20 years!

The RPH experience with the use of shaping to minimise RCS was quickly absorbed into the

Project Office analysis of options for a future combat rotorcraft and contributed to work already

completed on novel cockpit geometry for optical glint suppression. Awareness of these issues

also influenced Westland’s proposal for a lozenge-shaped fuselage cross-section for the NH90

helicopter, made by Smith as part of the NH90 Configuration Team during the Feasibility and

Pre-Definition Study (FPDS) Phase (prior to the UK’s withdrawal from the programme).

Figure 15. The proposed Westland solution to PHOENIX took full account of signature

reduction requirements


151

7. CONCEPT STUDIES AND TECHNOLOGY DEVELOPMENT

7.1 Funded Pre-Feasibility Studies

During the 1970s, the RAE funded a number of studies on advanced configurations to determine

their capability, maturity and key risks. This ‘look-ahead’ activity was primarily conducted to

determine if such concepts were sufficiently promising to be examined in more detail as future

operational requirements were defined.

This work included examination of rotorcraft with supersonic rotor tip speeds (24) and comparison

of the potential of conventional helicopters, compound helicopters and co-axial lift-offset rotor

(Advancing Blade Concept (ABC)) designs configured for attack missions (reported in June

1978) (Figure 16).(25)

A more technology-oriented study (26) examined the potential impact on design of future threat

developments – including non-nuclear electro-magnetic pulse (NNEMP), and laser sensor

damage weapons. The recommendations here included minimum area transparencies and virtual

(look through structure) displays (Figure 17). It is fair to say that this work, together with the

RPH signature treatment studies, had a significant influence on subsequent in-house attack

helicopter concepts.

Figure 16. Example Pre-feasibility concept studies examining supersonic rotor and

compound offset-lift configurations


152

7.2 Company Research Activities in 1980s

Under the “Pathfinder” umbrella, basic research into improved rotor aerodynamics, rotor

construction, transmissions and structural concepts were underway. These activities gave rise to

the BERP3 rotor developments which can be seen today on Lynx Wildcat and Merlin but which,

at this time, offered the promise of substantial benefits but were as yet unproven.

The Advanced Engineering Gearbox (AEG), using principles originated by Jupe, was able to

combine a much reduced mass with a level of robustness that was fully compatible with a rugged

battlefield helicopter: the principles embodied in this configuration were subsequently applied by

Sikorsky to the RAH-66 Comanche, CH-53K and the Lift Offset co-axial demonstrator

programmes.

Airframe structural testing was carried out using both titanium and carbon composite frames

linked by composite shear panels giving excellent crashworthiness and long life: this basic form

of construction was later carried through for Merlin though with metallic construction in place of

composites.

Figure 17. Artist’s impression of a design for operation in high threat environments,

including advanced electromagnetic threats


153

Project Office proposals for future types used a range of these technologies as appropriate but the

BERP rotor and AEG transmission principles would be typical features of all work on the combat

helicopter studies.

Helicopter agility, particularly in the nap-of-the-earth (NOE) environment, was the subject of a

specific and novel solution to the problem of quickly stopping a low drag helicopter from high

speed without gaining height. Twin tail rotors were introduced able to operate in opposition

during an autorotative stop to prevent a main rotor overspeed by acting as a rotor brake. The

application of this concept to an attack helicopter was quickly seen as also advantageous to a

naval anti-submarine warfare (ASW) mission where minimum dip to dip time was regarded as

vital to mission success. With appropriate care it was suggested that the twin tail rotor would

provide a valuable element of battle damage tolerance as well, unavailable with a traditional

configuration. A patent application was submitted relating to this concept (Figure 18). (27)

One other activity developed within the Projects area was the introduction of a design synthesis

methodology in the preliminary design process. The spur for the design synthesis methodology

came with the arrival of Paul Chapman from British Aerospace at Warton, who recognised that

the Project Office was well placed to create a helicopter design synthesis model, because of its

existing understanding of the selection of rotor design, stressing capability, mass estimation tools,

and its validated performance estimation model.

Such a model takes customer requirements in terms of payload, endurance, operational envelope,

flight performance, engine failure requirements, together with other constraints and, from an

initial starting mass estimate iterates onto an aircraft definition in terms of weight, blade area,

number of blades, engine and gearbox ratings, and other key characteristics. This tool was used

Figure 18. Twin tail rotor patent application diagrams and potential application to WG.38

(twin tail rotor WG.34)


154

with great success to support the configuration definition of NH90, during its Feasibility and Pre-

Definition Study (FPDS), while the UK remained in this programme. The Design Synthesis tool

was specifically used in support of the definition of an attack helicopter able to meet GST 3971

(WG.45), where questions arose concerning the impact of manoeuvre capability requirements on

the aircraft characteristics.

Mission avionics and avionics systems integration was the subject of specific research activities

undertaken by the Advanced Engineering Department, initially under Mike Pengelly and latterly

Jeremy Graham. This work was to be used by the Future Projects team to provide an assured

definition of expected performance, space, weight, power and volume characteristics, which were

then used in the configuration of the vehicle and the definition of its mission capability.

Similar applications provided key study inputs to the NH-90 and A129 LAH programmes as well

as internal Westland project studies. Of particular note was the fibre optic data bus hardware

development which demonstrated an optical implementation of Mil Std 1553B data bus protocols

during 1982 and a fully functional wavelength division multiplex solution during 1988. The latter

was regarded by the Company as the preferred data bus backbone for the survivable battlefield

helicopter because it offered the means to transmit all mission data, including video, on each of

multiple pathways giving a combination of redundancy and light weight that was, and remains,

unrivalled (28).

7.3 Consideration of Light Battlefield Helicopter concepts

Studies relevant to the emerging LCH/LAH requirements began in 1982 and were informed by

the understanding that a small, robust and cheap airframe would be an essential ingredient of a

successful program.

WG.42, which emerged in January 1983, was configured to meet the requirements published as

FINABEL 19.A.12 (29). This sought a very light weight (less than 4 tonnes), single-engine, two

crew, dedicated armed Light Battlefield Helicopter. WG42 was very simple and robust, but the

FINABEL study presented a challenging backdrop in that the User community had anticipated

target weights dating from MoD studies completed around 1979 which were significantly less

detailed than the analysis undertaken by the Future Project team.

The basis for these weight expectations is unclear but it is not unreasonable to assume it was

based on configurations having minimal equipment fits and also did not take important, but to a

degree hidden, mass-drivers like crashworthiness, redundancy, self-protection systems and

electronic systems hardening into account.

As a result of the 1979 meeting between the Company and the Future Army Helicopter Steering

Group (FAHSG) (see section 4.4 above) the MoD were able to compare the estimates created by

the Future Project group with these earlier estimates. Although complicated by the Company

estimates being based on technology re-use across many platforms (to reduce costs at the expense

of optimum design) the comparison is stark and was to influence the MoD strategy from here

onwards.

The target weight expected by the User for compliance with the FINABEL anti-tank variant was

2.7 to 3.6 tonnes. Westland’s proposal was 5.0 to 7.0 tonnes. For calibration, 3.6 tonnes was the


155

baseline Lynx target weight, but the Lynx AH.1 with TOW missiles weighed 4.5 tonnes and the

Lynx AH.7 with an improved sight plus some DAS equipment came in at 4.8 tonnes. Realistically,

compliance with the FINABEL requirements for crashworthiness, Defensive Aids Suite (DAS)

and Mast Mounted Sight (MMS) would be likely to lead to weights in excess of 5.0 tonnes even

assuming an optimised design approach.

WG42 was the first Project Office proposal having the ultra-low glint canopies fitted as separate

cupolas at each crew station. These were curved and sloped outward to reflect glint, from sources

at or above the horizon, downwards. The expectation was that this would prevent the aircraft

being detected at long ranges by the bright flash (specular reflection) of sunlight reflected back to

the enemy observer (Figure 19). The problem was analysed by Jupe and led to a patent application

being made, although ultimately this was not pursued.(30)

Figure 19. WG.42 was Westland’s proposal to meet FINABEL 19.A.12 and was the first

Westland concept to be schemed with a low-glint canopy geometry


156

8. THE OPTIONS FACING THE OPERATIONAL USER

8.1 Programme Options

Before discussing the various projects examined by the Advanced Engineering Team within

Westland Helicopters, it is worth summarising the position facing the operational user in the early

1980s. Lynx AH.1 was in service, primarily as a utility helicopter, but with an important

secondary anti-armour role.

In this role, it was armed with eight Hughes TOW wire-guided missiles, supported by a roof-

mounted Hughes optical sight (manufactured under licence by British Aerospace) for target

acquisition and missile guidance. The TOW missile system could engage targets out to 3,750 m

(12,303 ft) with flight times of up to 20 seconds using a semi-active command to line-of-sight

(SACLOS) system which assured ease of use but accuracy came at the expense of having to

maintain continuous view to the target. Use of the system from behind cover was only partially

successful at masking the helicopter from view: vulnerability to the Warsaw Pact ZSU 23/4 radar

guided air defence weapon system was a recurring concern.

Elsewhere, the 1970s had seen the US Army launch an Armed Attack Helicopter competition,

which resulted in the 1976 selection of the Hughes (subsequently McDonnell Douglas

Helicopters and then Boeing) AH-64A Apache as the winner, with approval for full production

following in 1982 (Figure 21).

Figure 20. A Lynx AH Mk7 from 4 Regiment Army Air Corps equipped with TOW in the

first Gulf War in 1991. Source: Army Flying Museum, Middle Wallop


157

The AH-64A was heavily armed with Rockwell (subsequently Lockheed Martin and Boeing)

Hellfire laser guided missiles, unguided 70 mm rockets and a 30 mm cannon (the Hughes M230

Chain Gun) with up to 1,200 rounds of ammunition. The crew were equipped with helmet-

mounted sights and the main nose-mounted Target Acquisition and Designation System/Pilot’s

Night Vision System (TADS/PNVS) sensor provided target acquisition, laser target designation

and pilot’s night vision functions.

The Hellfire missile offered twice the range of TOW at significantly increased speed of flight.

The warhead was larger, with a tandem charge version under development for the defeat of

explosive reactive armour (ERA). Although still requiring continuous laser target designation

during the missile’s flight, this designation could alternatively be provided by a Scout helicopter,

or by ground forces. The scout helicopter developed to support AH-64A indirect fire operations

was the Bell OH-58D “Kiowa” equipped with a long-range mast mounted observation sensor.

Using this sensor, the Scout was able to maximise its use of cover to minimising its detectable

signature and allow targets to be located and designated by laser.

This all represented a tremendous increase in capability compared with that available from first

generation armed attack helicopters and, naturally, the Army Air Corps were extremely interested

in the capability of Apache.

The Apache had won the US Armed Attack Helicopter competition in 1976, having been down-

selected (over the Bell YAH-63). The British Army were greatly interested in the capability of

the type, not least because of its heavy armament of long-range missiles. There was certainly a

body of opinion in the user community, once the type entered full production in 1982, that this

was the benchmark capability available in the West.

Figure 21. A Hughes YAH-64 prototype, later produced by McDonnell Douglas and

Boeing as the Apache, the US Army’s primary attack helicopter


158

Life was not that simple, however, as there were significant obstacles to such a course, as

summarised below:

“In 1975, the helicopter manufacturers of the UK, France, Germany and Italy signed an

MOU (Memorandum of Understanding) whereby they agreed to consider collaboration on

future projects. This led to a Ministerial Declaration of Principles on Helicopter

Collaboration, in 1978, and to the establishment of an intergovernmental Steering

Committee for European Helicopter Collaboration to work with operational staffs and

Industry.” (14)

Up to this point, the underlying assumptions that formed the foundation of the General Staff

Target for a Light Attack Helicopter (GST3971) (31) were as follows:

“After examining all other options, we have refined our requirements around an essentially

light helicopter (4/5 tonnes) with a significant payload of 8 LR TRIGAT dual role + light

quarter MG, and endurance of 2.5 hr and with great emphasis placed on survivability and

(Reliability, Availability, Maintainability – Durability) RAM-D. I must make it clear that

we see LAH in the direct fire role but unlike the excellent AH-64 we have no suppressive

fire requirement.”

(From DDOR7 presentation outline on LAH concept of operations, 20 February 1985.) (32)

It should be noted that the UK concept of operations was to deploy the LAH as a direct fire

weapon system. That is, it would be able to seek out, recognise as hostile and prosecute targets

without a reliance on other resources. As such, vulnerability when facing a sophisticated air

defence capability was of prime concern.

• Summary of requirements: (33)

“Survivability is of vital importance on the high threat battlefield. The Group has come to

the view that key features are a MMS (Mast Mounted Sight) and the greatest possible

reduction in visual, aural, radar and IR signatures; resistance to battle damage; and speed

and agility, both in the face of the ground threat and to enable the helicopter to defend itself

if attacked by enemy helicopters”.

(Other than resistance to battle damage and its innovative engine exhaust IR suppressor, AH64

did not conform to any aspect of this description.)

• The Secretary of State for Defence, in line with the Ministerial Declaration of Principles,

was seeking a solution based on European Collaboration. There were two candidate systems

available, the Franco-German PAH2 / HAC3G (Hélicoptère Anti Char 3rd Generation – French

attack variant of PAH-2) and the Italian Agusta A129.

• Westland Helicopters were actively working with Agusta to bring the new EH101

helicopter (later to become Merlin) to fruition. Simultaneously, Westland was interested in

pursuing national solutions for the attack helicopter. In support of this aim, WHL produced a

proposal (WG.44) based on the existing (part PV and part MoD-funded) research and technology

programme. This was followed by a WG.45 configuration showing full compliance with

GST3971. Westland had also signed an MoU with McDonnell Douglas agreeing in principle to

team together to offer AH-64 into the UK, should the opportunity arise.


159

Faced with this plethora of choices and constraints, the MoD decided to set up a Phase 1

Feasibility Study (34) under the leadership of AVM J A Porter, DGA2 to ascertain the status and

capability of the various projects on offer; the prospects that they offered for collaboration; and

any industrial implications that might result.

The options considered by the Phase 1 Feasibility Study were as follows:

• The German-French PAH2 / HAC3G

• The Agusta A129

• A UK National Development

• An Off-the-Shelf Procurement

- AH64

- LHX (US light Scout and Attack Helicopter programme)

This study report, which has recently been made public within Reference 32, provides

considerable insight on the Army Operational Requirements Staffs’ views of the different

projects at this time.

Relevant comments from the MoD Phase 1 Feasibility Study are included below against the

individual proposals. In reading these, it is perhaps worth bearing in mind a contrasting summary

of the Users’ attitudes provided by Dorman in Reference 35 (Defence Under Thatcher):

“Heseltine, in contrast, pressed for a European solution and overruled the army. … The

army were convinced that the study of the Agusta A129 would reveal it to be unsuitable for

the environment of the Central Front but acquiesced to Heseltine’s decision hoping in the

long-term for Apache to be reconsidered. By accepting the A129 option, they had at least

obtained political support for the requirement”.

Dorman goes on to say that the army took the long view when reluctantly acquiescing to the

A129 LAH Feasibility and Cost Definition Study (FCDS).

He states:

“More importantly, by acquiescing, the funding line for a new attack helicopter was created

within the LTCs (Long Term Costings), which could then be re-earmarked for the Apache

when, as expected, the feasibility study confirmed the army’s conclusions about the A129.”

8.2 Key Requirements

The MoD Operational Requirements staff, in consultation with a range of stakeholders,

developed a set of requirements for the new Light Attack Helicopter, known as GST3971. A

summary of key requirements is given below; certain requirements were relaxed for the four

nation Joint Staff Target (JST) that applied to the later four-nation Agusta A129 LAH study –

where relevant, this is indicated below:

8.2.1 Selected GST3971 (first draft) Requirements

The first draft of GST3971 was written to provide an assessment structure allowing the MoD to

conduct the in-house Phase 1 Feasibility Study referred to in Section 8.1. Its content defined the


160

generic capability required, while outlining some specific key requirements, which are

summarised below.

High level capability: a dedicated LAH capable of fighting in adverse weather day and night. Its

primary role would be anti-tank but it should be able to discharge a secondary anti-helicopter role

by carrying the appropriate weapons.

LAH must be specifically designed for the attack of armour and armed helicopters. Its primary

weapon will be Long Range TRIGAT and other weapons will be required for less hard targets.

While primarily aimed at operation in North-West Europe, it must be capable of operations

worldwide, albeit with some reduction of specified mission performance.

Specific capabilities

• Gunner’s sight to be mast mounted

• Night vision: Pilot night vision goggles (NVG), Gunner thermal imagery (TI)

• Seating: pilot in front?

• Crash resistance: essential 85th percentile, desirable 90th percentile

• Engines: one or two RTM322?

• Centralised digital databus: required

• Automatic Flight Control System (AFCS): required: modes to include automated

instrument approaches, auto-transition to the hover. Feasibility of high authority Active

Control Technology (ACT) to be advised upon.

• Mission management facilities to reduce crew workload, multi-function displays

• Navigation system to comply with UK Civil Aviation Authority (CAA) rules for

Instrument Flight Rules (IFR) flight in controlled airspace

• Mission performance: 2 hr 30 min plus 20 min reserve at 500 m ISA +15 C (+59 F) and 2

hr plus 20 min reserves at 2,000 m (6,562 ft) ( ISA+20 C (+68 F).

• Ferry Range: 1,200 km (648 nm) at 500 m (1,640 ft) ISA+15 C with 30 min reserves

using external auxiliary tanks

• Engine failed performance (twin engine aircraft)

- Possible to maintain a climb rate of 0.75 m/sec (2.5 ft/sec) one engine inoperative

(OEI) at the start of both primary and alternate missions

- Safe fly away from 5 m (16 ft) hover agl in nil wind (interpreted as hover in these

conditions on one engine at emergency power level)

- At 2,000 m ISA+20C, take-off vertically in nil wind without weapons but with fuel

for 50 km (27 nm) and transition to forward flight

• At maximum all-up mass (AUM) and 2,000 m ISA +20C achieve the following

performance:

- With all weapons fitted continuous hover with 5% thrust margin in still air and, by

using power above the continuous rating, be able to achieve a 15% thrust margin

- Transient 3 g at 185 kph (100 knots)

- Max continuous speed: not less than 300 kph (162 knots)

- Dash speed for one minute 320 kph (173 knots), desirably 350 kph (189 knots)

• Air Transportability: Carriage in C-130, C160 and their replacements, with preparation

taking less than one hour using 4 men

• Service life: 9,000 hr or 25 years

• Maintainability: 3 maintenance man hours per flight hour (MMH/FH)

• Expected AUW: 4,990 – 5,445 kg


161

8.2.2 Selected JST Requirements (1987 A129 LAH Study) (45)

The main differences here are a reduction in the severity of the datum ambient conditions from

2,000 m (6,562 ft) ISA+20 C (+68 F) to 500 m (1,640 ft) ISA+15 C (+59 F) and a reduction of 20

minutes in mission endurance. LAH mission requirement: 2.5 hr endurance at 500 m ISA+15C

with mission profile 25% cruise at 300 kph (162kt), 60% hover and low speed, 30% 55-150 kph

(30-81 knots), 8% 150-220 kph (81-220 knots), 2% 220-320 kph (119-173 kt), 20 min reserves

desirable.

Point performance 500 m ISA+15, all weapons in place:

• Fly away from 5 m (16 ft) hover above ground level (agl) in nil wind (interpreted as hover

in these conditions on one engine at emergency power level)

• Hover out of ground effect (oge) with 10% thrust margin (15% desirable) within twin

engine 30-minute rating

• Fly at 300 kph within max continuous power

Survivability

• Essential requirement to minimise distinctive signatures – low probability of detection

being highest priority within overall survivability

Mission System

• Mission system with flexible architecture, 50% spare capacity and:

- Mission management system with low workload man machine interface

- Euromissile Dynamics Group (EMDG) TRIGAT LR with associated MMS

- Electromagnetic Compatibility (EMC) compatible with STANAG 4234

- Extensive comms fit (2 VHF/FM) one secure, VHF (AM), UHF (AM), HF SSB)

- Night vision compatible cockpit

- Fly-by-wire or fly-by-light (FBW/FBL) control system

- Wide range of AFCS modes

- Extensive Defensive Aids Suite

Reliability & Maintainability

• Mean Time Between Mission Failures (MTBMF) 40 hours

• Logistic Defect rate 167/1,000 flying hours

• Refuel and rearm in 10 minutes (4 men)

• Change each major component in 2 hours with easily portable equipment

• MMH/FH less than 3 (peacetime utilisation)

• Airframe fatigue life not less than 10,000 hr

Configuration

• Tandem seat (pilot in front seat)

• Best possible crew field of view a high priority

• Possible to stop the rotor within 45 seconds of touchdown


162

9. WG.44

Figure 22. WG.44 model showing retractable weapon system and body shaping; this

design retains a Lynx dynamic system

Figure 23. General Arrangement of the WG.44, a private venture design based on the

Lynx dynamic system and a range of technologies under development at Westland


163

During the early 1980s, Westland participated in the Air Vehicle Signature Reduction Advisory

Group (AVSRAG), which provided a highly valuable information exchange across the airframe

and engine industry and with the MoD Establishments – RAE and RSRE. This collaboration led

to the Project Office looking at design for reduced signatures and other measures to counter

various anticipated electromagnetic threats.

Radar cross-section was a hot topic (particularly a result of the contemporary Falklands Conflict).

Westland examined concepts for reduced radar cross section attack helicopters. The first design

concept, WG.44, originated from a discussion between Dr J P (Jeff) Jones, Research Director for

WHL, and Controller Aircraft (CA), who asked what Westland could show as an attack helicopter

building on in-house research and the results of the MoD Research-funded activities. (36, 37)

WG.44 was schemed around a Lynx 3 rotor system (with British Experimental Rotor Programme

(BERP 3) blades) and diameter of 12.8 m (42 ft) incorporating a mast mounted sight (MMS),

with a composite flex-beam tail rotor hub, and an intermediate gear box from Westland WG30-

300. Key emerging technologies embodied within the active R&D programmes included higher

harmonic control (HHC) for vibration control (eventually emerging as ACSR – Active Control of

Structural Response - which has been very successful and is now widely applied around the

world to many helicopters via actuators manufactured by the Lord Corporation); a high ratio

conformal gearbox, based on the Advanced Engineering Gearbox (AEG) demonstrator; and the

optical Mil Std 1553 databus.

Power was to be provided by two RTM 322-01 engines rated at 2,100shp take-off at Sea Level

ISA, or, for the single engine option, one 2,300HP “Step 1” growth RTM 322-03. Aluminium

Lithium alloys were to be used in the airframe. The equipment fit included a laser obstacle

warner (later realised on Agusta Westland AW101 SAR (Search and Rescue) for the RDAF

(Royal Danish Air Force), and CSAR (Combat Search and Rescue) for the AMI (Aeronautica

Militare Italiana)) and survivability features included armoured crew seats, body armour and an

armoured cockpit divider (including the upper transparent part) and local armour to protect vital

aircraft systems. Night vision was to be provided by night vision goggles (NVG). Camouflaged

apertures were used (shielded intakes), with upward facing cooled exhausts (akin to that later

provided on Omani Lynx Mk120, Lynx AH,9A and the AW159 Wildcat).

Mission compliance was judged against a mission based on 500 m (1,640 ft) ISA+15 C (+59 F), 2

hrs 30 min + 20 min reserve, 90 km (49 nm) out and back at 300 kph (162 knot), 110 minutes on

station. Single and twin-engine versions met the time on station point. The single engine could

approach the high-speed requirement but the twin fell somewhat short. A dual optical Mil Std

1553 fibre-optic databus was used to support the mission system and a fly-by-light flight control

system was offered, together with a shaped fuselage, conductively-coated flat canopy glazing and

retractable main anti-armour armament. The retractable weapon carriage was compatible with

TRIGAT, TOW, HOT, Hellfire and Air Defense Anti-Tank System (ADATS). An alternative

fixed weapon boom was compatible with folding-fin rickets (FFR), machine gun (MG) pods, and

the light series bomb carrier. There was a nose mount for the GECAL .50 calibre multi-barrel

gun, Stinger or Mistral.

The estimated mission gross weight for the single engine aircraft was 5,120 kg (11,288 lb) and,

although not designed against GST3971 (which was not available at the time that WG.44 was

schemed), the WG.44 was very close to meeting the demanding speed and agility requirements

that were to be included in that target.


164

Whilst the twin-engine aircraft had a slower cruise speed, it had more power than was required

and had “plenty of spare power in all corners of the flight envelope” (MoD assessment) (39).

The requirement for an air to air anti-helicopter capability was not explicitly defined. Air to air

weapon requirements had been studied by the Advanced Systems group in some depth with a

wide range of options considered. Concerned to optimise the weight of an appropriate system,

turreted guns/cannons were at this time shelved in favour of missiles. For WG.44 an installation

making use of the Raytheon FIM-92 “Stinger” was used as an illustration: Westland had recently

test fired Stinger from Lynx to demonstrate safe release and so had ready access to all installation

and integration matters.

Scale models of WG.44 were constructed, along with a radar cross section test model, which

provided very encouraging results when tested.

An initial patent application (38) was made in 1984 (subject to a Secrecy order imposed by the US

Government) regarding the weapon bay but was not followed up. The Boeing Sikorsky

Comanche was to adopt a very similar overall configuration, inclusive of the weapon bay, but

with a shrouded fan-in-fin canted tail rotor and greater attention to infra-red signature reduction.

It is clear from reading the MoD’s Phase 1 Feasibility report (33, 39, 40) that WG.44, in its single

engine form, was seen as a close match to the requirements. (39) It was felt that the WHL weight

estimate was light (by around 6%) - 5,120kg (11, 288 lb - WHL) versus 5,430kg (11,971 - MoD),

but there were a number of positive comments, as indicated below:

• The aircraft seems well balanced and should satisfy the main aims of the Staff Target

• WG.44 has a number of attractive operational features, notably retractable weapon

pods and fuselage design tailored to low radar reflectivity

Figure 24. Diagram from UK patent application GB 2177668A showing retractable

weapon installation


165

• Assessment (at para 75 & Annex D) suggest single RTM322-03 would be a very fast

helicopter close to meeting agility requirements, but short of hover thrust margin.

• WG.44 falls short by about 10% in terms of payload, endurance and flight

performance. This compares favourably with HAC3G and A129.

• One detailed point is worth noting. The WG.44/45 is designed to have retractable

weapon pods and some initial study has been done on a telescopic MMS. Both these

developments, albeit involving considerable cost and technical risk, have far reaching

implications for the future of helicopter design and a direct bearing on flight

performance and IR/Radar and visual signatures. It is considered that both these

aspects should be actively pursued during feasibility.

However, the report concluded that the technologies involved introduced significant development

risk (on new gearbox, active control system, fibre optic databus and retractable weapon carriage)

despite progress that had already been made at the research level on most of these technologies.

The WHL costs quoted had excluded costs for externally developed items – specifically the

TRIGAT weapon system and its associated mast mounted sight and the RTM322 engines. As a

result, WG.44 was regarded as an expensive option, by the time these factors had been taken into

account.

Furthermore, there were perceived to be concerns around industrial capacity; the wisdom of

introducing another competitor in this field; and the legitimacy of a national procurement

approach, given the 1978 Ministerial Declaration of Principles on Helicopter Collaboration.

The industrial capacity concern really arose in respect of the WG.45 submission (and is discussed

in more detail in Section 10 below) but was regarded by the MoD as being of equal concern in

respect of WG.44.

10. WG.45

The MoD customer indicated (at this time) that AH-64 was regarded as too large and detectable

(see Section 12, below) and that a smaller helicopter would be preferred, consistent with the

desire to study the Agusta A129 in greater depth. Reduced detectability combined with long-

range sensors and weapons were seen to be major contributors to survivability.

It was clear, however, that the MoD customer community (Users and OR Staff) were preparing

requirements ahead of the procurement of a dedicated attack helicopter to replace Lynx in the

anti-armour role. As draft copies of GST3971 (describing a Light Attack Helicopter) (31) became

available, it became possible to evolve the concept to take account of its content.

Outline proposals were provided to MoD and were considered as an input to the customer Phase 1

Feasibility Study Report (33), which was completed in November 1984.

This study, of a new design to be as compliant as possible with GST3971, and funded by MoD

(FS/RW) was begun prior to, but completed largely in parallel with, the MoD Phase 1 Feasibility

Study, being completed around the end of February 1985 (40 – 44). The result was WG.45, which

was based around an anti-armour armament of eight EMDG TRIGAT LR imaging IR missiles,

with a mast-mounted multi-band electro optical sensor mounted above the rotor.


166

Single and twin-engine concepts were examined for WG.45 and an attempt was made to balance

survivability and signature reduction features with the robustness and practicality required of an

attack helicopter operating from dispersed locations on battlefields world-wide.

WG.45 featured a new dynamic system (engines, rotor and gearbox) as well as a shaped fuselage,

drawing on the earlier WG.44 work.

A version of WG.45 with a conventional fuselage (not shaped for signature reduction) was drawn

to allow comparison to evaluate the penalties due to fuselage shaping (Figure 26). These

comparisons were included in the design synthesis modelling (Figure 27).

At the time that MoD were preparing their Phase 1 Feasibility Study (published November 1984) (33)

only limited information was available on WG.45 and it seems appropriate to quote verbatim the

summary of the design contained within the MoD report (41):

“WG.45 submitted in outline form only, was intended as a benchmark setting out the

company’s view of the kind of helicopter that would be necessary to meet the performance

parameters of GST3971 in all respects.

It would have an all up weight of 6,250 kg [13,779 lb], employ a 6-blade rotor of 14.5 m

[48 ft] diameter and be powered by twin RTM322s in -03 (2,300 hp) form. It would be an

expensive helicopter in development.”

[WG.45 configuration notes: the characteristics given above represent the aircraft when outline

details were first made available].

Figure 25 Twin engine WG.45 pre-feasibility study concept to meet GST3971


167

Figure 26 A conventional LAH design without signature reduction features was generated

for comparison purposes as part of the Design Synthesis modelling activity

Figure 27 Use of the WHL Design Synthesis model to debate requirement trade-offs

during Pre-feasibility studies of WG.45 against GST3971


168

A review meeting held at Middle Wallop in November 1984 (42) showed that the blade area

required (based on the WHL Design Synthesis model) was being driven by the demanding

transient manoeuvre requirement (3g at 100 kt), applied at 2,000 m (6,562 ft) and ISA +20 C

(+68 F). The meeting agreed to relax this requirement, provided that a hover thrust margin

equivalent to that of a lightweight Lynx was maintained.

The meeting noted that

‘The datum aircraft to meet the GST requirements was emerging as a 5,900kg (13,000lb)

machine with a 6 bladed 13.72m (45ft) diameter rotor. The rotor sizing was being driven

by the transient high ‘g’ manoeuvre requirements, or rather the project design interpretation

that had been placed upon them. Even if this requirement was relaxed, the machine would

have about 30% greater excess rotor thrust and double the installed power margin compared

with a Lynx at 8,000 lb AUW.’

The design synthesis modelling indicated that with a relaxation in the ambient conditions for

transient manoeuvre, the main change would be a reduction to a five-blade rotor. The mass

saving that resulted would allow a low RCS shaped fuselage at around the same AUW as the

original datum aircraft.

Other characteristics identified at this meeting were a sustained cruise at 300 km/hr (162 kt)

(VNO – maximum normal operating speed) with a VNE (never exceed speed) of 333 km/hr (180

kt). Dash speed requirements would be met by transient operation between VNO and VNE, an

approach which drew upon the precedence of Sea King SAR operation.

The final report (43), issued in April 1985 indicated that full compliance with GST3971 required 6

blades, 6,300 kg (13,889 lb) AUM, and 8% power growth over available RTM 322. Some

relaxation of requirements gives a 5-blade rotor, 6,000 kg (13,228 lb) AUM, with a standard

RTM engine giving adequate power. A single engine solution saved 600 kg (1,322 lb) at expense

of the engine out failure performance inherent with the twin engine option. The aircraft dynamic

system would also be compatible with a 13+ troop transport helicopter. Further work was

recommended on transient manoeuvres, OEI modelling and autorotation performance modelling.

The weapon systems proposed were TRIGAT LR, GECAL .50 calibre gun and a new air to air

missile, if optimum performance was to be achieved, possibly deriving from proposals received

from BAE Stevenage covering a small but hypersonic IR guided munition. Mixing of air to

ground and air to air missions would adversely impact performance in each role. Gun

engagement was to be automated following target designation.

The MoD summary (41) continues, however:

“Westland themselves have made it clear that they would not wish WG.45 to be pursued

because they do not possess the engineering capacity to develop it alongside EH101; they

think its market prospects would be poor; and they think the WG.44 a more cost effective

solution for the British Army. The WG.45 is therefore not considered further in the report.”

It is not clear to the authors how these specific views from Westland were provided, possibly in a

covering letter to the outline information provided, or conceivably in a Business Development or

Senior Management briefing. It is clear, however, that these observations had a fundamentally


169

negative effect on the prospects for both WG.44 and WG.45. Further related comments extracted

from the MoD Phase 1 Feasibility Study report are provided below (43).

WG.44: “In our view, Westland could not take on a programme of this magnitude without

substantial risk of delay to EH101 and we believe that to adopt this course would be most

unwise.”

WG.44: “ … Given Westland’s dependence upon the success of EH101 for their future

commercial strength, we conclude that it would be most unwise to add a further

development burden of the magnitude of WG.44 to the company’s workload. To do so

would in our view be to prejudice the success of both.”

“We therefore believe that the overall effect of a national WG.44 development would be

damaging to UK Industrial interests.”

International perspective: “What would undoubtedly attract unanimous criticism from our

three partners in the 1978 Declaration (of Principles for Co-operation on Helicopter

Programmes) would be a UK decision to opt for a national programme, thus triplicating

European activity in the anti-tank helicopter field, or a UK decision to buy from America,

even under licence-build arrangements.”

One point that certainly arises relates to the realism of the MoD expectations that GST3971

would result in the procurement of a Light Attack Helicopter, with an aspiration that its

maximum mission weight would be less than or equal to 4,500 kg (9,921 lb). The WG.45

activity showed that, even with a relaxed manoeuvre requirement and without full attention to

signature reduction, a more realistic mission weight for a compliant aircraft would have been

around 5,800 kg (12,787 lb).


170

11. WG.47

WG.47 represented an attempt to develop the ideas that originated with WG.44 and WG.45 and

to explore the implications of designing an attack helicopter with maximum priority given to

signature reduction.

Figure 28. WG.47 models to compare single and twin tail rotor configurations and show

the alternative low-glint canopy design

Figure 29 Schematic views of WG.47 showing conventional and low glint canopies and

single-sided exhaust configuration


171

In September 1985, the UK, France, Germany, Italy and the Netherlands launched the Feasibility

& Pre-Definition Study (FPDS) for the NH90 maritime and land-based helicopter for ASW and

Utility operations. Dr Smith was appointed to the Configuration Team for the NH90 FPDS,

which ran until December 1986. Westland made significant inputs into the configuration

definition, making use of the previously mentioned Design Synthesis toolset. The UK were

withdrawn from the programme on 27th February 1987.

By then, planning was underway for a four nation (Italy, UK. Spain, Netherlands) Feasibility and

Cost Definition Study of a developed version of the Agusta A129 (A129 LAH) against an agreed

four-nation Joint Staff Target (JST) (45). This study is discussed further in Section 12.2, below.

Dr Smith was appointed Joint Technical Co-ordinator for this project and, within Westland, became

Chief Design Engineer (LAH).

Consequently, the WG.47 activity was managed by Paul Chapman and others from within the

Advanced Engineering team.

11.1 WG.47 Evolution

Whereas the WG.45 had been shown in one variation having a shaped fuselage following the

principles of WG.44 it had become increasingly clear that a significant, and therefore

operationally useful, reduction in observable signature would only be achieved if low

observability was considered as the most dominant design feature.

This realisation can be seen in the Lockheed F-117 “Night Hawk” configuration which was

unknown to the Project Office in 1986 but its subsequent reveal was followed with great interest

at Westland and with some sense of satisfaction (Figure 30). There was similar interest in the

Sikorsky/ Boeing RAH-66 “Comanche”, which appears to have accepted a greater compromise

than the F-117 but which nonetheless adopted many of the features considered necessary by the

team at Yeovil (Figures 30, 31).

During work on the A129 LAH collaborative program all MoD funded studies of a UK specific

AH solution was suspended. However, in order to better appreciate the consequences of

accepting a low observable (LO) signature as the “a priori” design requirement the Company

decided to invest PV funds into a study of a derivative WG.45 aircraft using all of the LO

experience then available to the team.

The shaping and construction of the fuselage was significantly refined, as far as possible all

external disturbances to the desired mould lines were removed and space was made available for

the latest “all aspect” infra-red suppressor defined by Rolls-Royce for use with the RTM-322

engine. All “hot” air was to be dumped into the suppressor and its air intakes were mounted

ahead of the engine bay to provide cooling of the engine bay and exhaust surfaces.

Grid like conductive structures were incorporated across all intakes though alternative geometric

solutions (plus RAM) were also considered for the engine intakes themselves, because ice

accretion on the grid covers would be likely to restrict all weather operations. Engine exhausts

made use of geometry and high temperature RAM to minimise their radar cross section.


172

Long wavelength infra-red signatures were minimised by wall cooling of the hottest parts of the

aircraft, by integrating all cooling air exhaust with the engine suppressors and by directing

exhaust gases from the suppressors in the direction of rotation of the main rotor. This ensured

that swirl within the rotor wake carried the plume away from the aircraft to avoid structural

Figure 30 The first public appearance of the F-117 in April 1990 confirmed the validity

of some of the approaches taken by WHL; the use of saw-tooth panel shut lines is one area

that was not anticipated. Photo Jim Smith

Figure 31 The Boeing-Sikorsky RAH-66 Comanche adopted some features that had also

been proposed in 1984-86 for the Westland WG.44 – WG.47 projects, most notably, the

retractable weapon launchers


173

heating creating an increased IR signature. This proposal has recently emerged in the Bell

Invictus concept being offered for the US FARA programme.

Surface finish paint schemes to assist in the minimisation of radiated short wavelength infra-red

emissions were considered but their compromise in respect of visual signature was assessed as

undesirable. The final paint finish followed that subsequently applied to UK rotorcraft as the

standard “low IR” solution.

The BERP rotor was already known to exhibit a low noise signature and consideration was also

given to the benefit of a reduced speed rotor for use in the low speed, nap-of-the-earth operating

regime. Fairings were proposed to fully enclose the main and tail rotor hubs, again with local

application of RAM as an alternative to otherwise awkward shaping. The radar signature of the

main rotor blades was recognised as a significant signature that must be suppressed: solutions

taken from the RPH proposals were incorporated but significant construction techniques were

also postulated. Recent technology demonstration as part of the Merlin BERP IV program has

proven that these concepts are practicable and achieve the desired result. The tail rotor was

assumed similarly treated as the main rotor but the definitive WG.47B derivative made use of two

canted tail rotors conforming to the basic fuselage shaping rules.

Visual signatures were primarily tackled by use of flat panel canopies, in the case of WG.47B a

facetted cupola design was used to ease manufacture and allow for a practicable integration of

narrow band optical filters and armoured glass. Human factors trials with a cockpit mock-up

demonstrated that the original cupola canopy was much too small to offer an acceptable field of

view. The definitive solution added weight to the design, significantly so if armoured glass were

to be used, but was sensibly compliant with accepted standards for field of view.

The chosen colour scheme followed that applied to the GR.7 Harrier where one basic colour was

used, but with countershading in areas of shadow.

11.2 Potential for further evolution

In retrospect, the design of the WG.47 could have been further refined in a number of areas. The

lack of a simple area weapon (turreted gun or rockets) was a significant operational compromise

and one that the Sikorsky/Boeing team working the RAH-66 resolved with a shaped “canoe”

fairing where the weapon tube was presented only when needed, thereby maintaining a low radar

cross-section (RCS) for as long as possible. Panel shut lines were always a source of concern but

the saw tooth solution adopted by the F-117 had not been considered; all panels that would be

opened and closed regularly could and should have been so finished.

A deliberate decision was made to clothe the main undercarriage in RAM rather than retract it.

Immediately forward of the weapon bay the tandem two seat WG.47 fuselage was close to 2.5 m

(8.2 ft) wide, leaving plenty of room for a fully retractable undercarriage to be installed. Crash-

worthiness concerns aside, the WG.47 should have been equipped with a fully retractable

undercarriage as was RAH-66.

The primary anti-armour weapon was to be TRIGAT LR which was a weapon system having its

own specialised mast mounted sight. This sight, though small in presented area, was not designed


174

for low observability; sight assembly shaping and hot air management should have been

considered.

The weapon seeker was required to scene match with the weapon sight prior to launch. Although

the process was expected to be of short duration and, once fired, the missile guidance was

autonomous, it was undesirable to expose the weapon before launch, or to have the weapon bay

open for any longer than strictly necessary. A true lock on after launch weapon would have been

a desirable solution and AGM114L RF (Radio Frequency) Hellfire would have provided this

capability, albeit without the same certainty over intended target engagement.

Cockpit field of view could have been further improved by a simple change of nose profile which

would have been a desirable and straightforward adaptation. Wind tunnel testing showed that

drag was high for an aircraft of this category: various measures were taken to minimise base drag

generated by the sharp chine lines and large flat bottom surface but none were especially

successful: the solution would likely have lain in refinements elsewhere, such as smoothing the

blunt fairing aft of the engine exhaust suppressors, or a change of the upturn angle of the rear

fuselage. RAH-66 was configured with no obvious suppressor fairings outside of the lines of the

rear fuselage and the base of its tail had no upturn at all.

WG.47 was presented to the AVSRAG where it generated considerable interest but no direct

support for the concept was forthcoming other than a contract for the development of a design

“handbook” that might serve to capture the experience gained in configuring an aircraft for

minimum RCS. (46)

Parallel activities under the A129 LAH contract did allow some attempt to be made to introduce

RCS reduction measures based on fuselage shaping but these would probably not have been

sufficiently effective to warrant their incorporation in a production solution.

Finally, Comanche and the recently revealed Bell Invictus proposal (Figure 32) both incorporate

a Fenestron-style fan-in-fin for yaw control and anti-torque purposes. This is another area that

was not addressed by the WG.44, 45 and 47. The advantage of this approach is that the

signatures of the yaw control device are masked from the direct frontal and rear aspects but it

seems unlikely to be sensibly compatible with the twin tail rotor configuration adopted for the

WG.47B. It also may be the case that the small physical dimensions of the fan-in-fin blades

would hinder a viable structural design to achieve an inherently low RCS as might be beneficial

for an all-aspect design.


175

12. AH OPTIONS EXAMINED BY WHL AH-64, A129 LAH, TIGER

12.1 AH-64A

Figure 32 The Bell 360 Invictus is a candidate for the US Future Attack Reconnaissance

Aircraft (FARA). Announced in October 2019, as well as internal weapon carriage and

shaped fuselage, it has the single combined exhaust solution (highlighted in inset) proposed

for WG.47 in 1986

Figure 33 The AH-64A Apache lacked a long-range sensor to allow direct fire attacks without

exposing the helicopter to enemy defences. Although highly capable, there were other deficiencies

against a number of the UK’s specific requirements


176

12.1.1 MoD views 1984-85

In November 1984, the MoD Phase 1 Feasibility Report (33) (and related documentation within

Reference 32) made the following observations about AH-64A (Figure 33), its capabilities and

scope for collaborative engagement, but the context appears very much aligned to the

contemporary politically inspired desire for European collaboration:

• Brief by Lt Col Hyde Smith SO1 CD(OR) ahead of a meeting (15/1/85) at Westland to

discuss WHL MoU on AH-64 (47).

“It is important that they are not given an unfounded sense of optimism and to that end they

must be informed that we, at the Secretary of State’s request, will be looking for collaboration

within Europe initially and will not be examining American alternatives until all European

options have been fully exhausted. Before the end of the meeting, we should take the

opportunity to advise WHL that in the event of being asked to collaborate in the A129 Mk2

venture, they should pursue this course with the utmost vigour rather than remain

committed to their MoU with the Americans on AH-64.”

• Telex to British Defence Staff Washington from DDOR7 7/12/84: (48)

“Subject remains very sensitive as Ministerial decisions expected on European collaboration

within the next three weeks. Must make position clear we are not looking at AH64 other

than future fallback position if European collaboration fails. In this context would consider

other off-the-shelf options. Emphasise our determination to succeed within Europe.”

• JA Porter (DGA2) Digest to Phase 1 Feasibility Study Report (November 1984): (49)

“AH64 in its present form is not a survivable direct fire weapon system and to modify to

accept LR TRIGAT and MMS would be very expensive.”

• Phase 1 Feasibility Study Vol 1 Comments on AH-64: (50) AH64 Large helicopter.

Mission mass around 7,000 kg (15,432 lb0. Mid-70s conservative design. Metal blades, two

widely separated T700 1,264 kW (1.695 shp) engines for ballistic survivability. 30 mm chain

gun, max 1,200 rounds. Airborne performance falls short of GST3971 in speed and agility.

Hughes MDHC foresaw possible need for RTM332 as a way of increasing UK content and

encourage UK component manufacture.

“We believe that this might not prove to be a very easy process since AH64 weapons

systems manufacture is already heavily subcontracted within the US; it could well therefore

be necessary to negotiate licences with each US sub-contractor.”

• “Hughes tacitly admitted that, with its nose-mounted sights and very considerable bulk,

Apache is not a survivable direct-fire anti-tank weapon system for the Central European

Theatre. The US Army would operate it from concealed positions as an indirect-fire

weapon with target designation for the Hellfire missiles being carried out by a ground-

based laser designator or by a suitably equipped Scout helicopter.”

• “To operate as a direct fire weapon system as required by GST3871, therefore, Apache

would need to be developed to incorporate a mast mounted sight and the TRIGAT weapon

system.” This implies a high cost penalty, particularly if you throw in the cost of the Scout

helicopter to allow operation in an indirect fire mode.


177

• Phase 1 Feasibility Study Vol 1 Conclusions in respect of AH-64: (51)

“AH64 … lacks a mast mounted sight, without which we regard it as a highly risky

proposition as a direct fire weapon system for use in Central Europe; it could however be

developed to take MMS, TRIGAT weapon system and RTM322 engines, but at a cost

which, both in total and DCF terms, makes it an extremely expensive solution. A US

purchase would cause us severe difficulties with our European partners.”

• Phase 1 Feasibility Study Vol 2 Performance: (52)

“The AH64 is a large and complex helicopter but is fitted with a nose, rather than mast

mounted, sight.”

• “In its primary mission configuration with 8 Hellfire and 320 rounds 30 mm ammunition,

the AH64 is required to deliver the following performance at 4,000ft, 95F: 145kt cruise

speed, 1.83 hr endurance. This requires a take-off mass of 6,665 kg [14,694 lb], close to

the structural design mass. The maximum take-off mass is 8,005 kg [17,648 lb].”

• Assessment

“The AH64 is undoubtedly a large, complex and expensive helicopter. It is sobering to

consider that the requirement against which it was developed was not dissimilar to

GST3971.” “The AH64 achieves an endurance of only 1.83 hr against 2.5 hr plus reserves

sought in GST3971, admittedly in less severe ambient conditions.”

• Loose Minute D/OR12/3/1/38/8 28 September 1984 (53) – Operational Requirement

Assessment: Procurement options to meet GST3971 (LAH):

“The AH64 … far exceeds the requirements specified in GST3971 with two notable

exceptions flight performance and survivability.” “Bearing in mind the size of this

helicopter and engine power available (2XT700, each of 1,694shp) the flight performance

of the AH64 is disappointing.” [Authors’ note: likely to be due to transmission limits,

rather than power available, per se.]

• Survivability:

“… it is obvious that this large helicopter gives out powerful signatures. To this must be

added the significant exposure times of the TADS/PNVS nose-mounted sighting system …”

“It is clear that the Apache is not designed to avoid detection, but rather to survive once

detected. This runs contrary to GST3971’s basic philosophy of incorporating all measures

to avoid detection.”

• Summary:

“The AH64 is a large and not particularly fast helicopter, which carries an impressive

firepower of missiles, rockets and cannon (Figure 34). It was designed and constructed to

meet a totally different requirement than GST3971. In assessing AH64 to meet an attack

helicopter requirement for the British Army, it suffers from 3 major drawbacks: a) it is not

an agile helicopter, with a disappointing flight performance; b) it offers more than is

required, for example the British Army has no suppressive fire requirement, which, with its

rockets and cannon, the AH64 has in abundance; c) it is considered most vulnerable with


178

strong signatures and long in-contact exposure times, in the direct fire role. In the indirect

fire role there would be problems in Command and Control and the not insignificant matter

of an additional purchase of Scout designator helicopters.”

12.1.2 AH-64A Westland Assessment against Joint Staff Target for LAH (1988)

Even though the customer was emphasising a lightweight solution for its new attack helicopter,

Westland felt that it would be prudent to engage with the then Hughes Helicopters to establish a

formal industrial partnership in relation to Apache. An initial Memorandum of Understanding

between the two Companies was signed in 1983 at a time when there was little or no official

MoD interest in Apache. Further, at a meeting with Controller Air shortly afterwards the

prospect of an AH-64 based proposal was dismissed with the words “Westland - you need to

understand that Apache is the very essence of what we do not want”! In the fullness of time,

however, it was to become clear that the User thought otherwise.

Following up on the signing of the MoU, Westland engaged with the (by then) McDonnell

Douglas Helicopters to review the capability of AH-64A against the UK’s draft requirements for

LCH/LAH. Smith and Goddard visited MDHC at Mesa, Arizona, in 1988 and conducted a

Figure 34 Potential Armament Options for Various AH-64A Mission Types showing the

range of firepower options available


179

detailed assessment of the Apache against the latest MoD requirements, as expressed in the Joint

Staff Target for the A129 LAH program (45).

The report written after this visit (54) assessed the base AH-64A (with assistance from MDHC)

aircraft, and two further stages of development: Stage 1 - Base Aircraft plus mission system

updates; and Stage 2 - as Stage 1 but with the addition of TRIGAT.

The analysis presented here concentrates on the base aircraft, as the changes anticipated in Stage

1 and Stage 2 were rather speculative.

12.1.3 AH-64A Base Characteristics (summary)

• Two 1,264 kW (1,696 shp) GE T700-701

• Structural design weight 6,649 kg (14,660 lb)

• Tandem seating pilot in rear

• 8 Hellfire plus Hughes M230 30 mm gun and wide range of other ordnance

• Primary mission weight with 8 Hellfire and 320 rounds 30 mm ammunition is 6,700 kg

(14,773 lb) (just above structural design weight).

• Nose mounted TADS/PNVS plus IHADSS (Integrated Helmet and Display Sight System)

• Mil Std 1553A databus with limited redundancy and no mission management facilities

• Hover performance design point: Hover out of ground effect at 4,000 ft (1,219 m) and

95F (35 C) corresponding to ISA +28 C

• Hover design point determines the twin engine transmission rating of 2,109 kW (2,828

hp), which matches the power available from two GE T700-701 engines in these

conditions.

12.1.4 Areas of non-compliance with JST (Base AH-64A, Section 4.1.7 of reference)

Reference 54 identifies a number of key areas where there are significant shortfalls in

performance compared with either the JST (54), or the GST (31). The main areas of concern

identified during the Westland technical visit were as follows (Section 4.1.7 of Reference 54).

• Engine failed performance

- Related to the lack of an emergency power rating from T700-701 engine and by

the gearbox single engine transmission rating.

• Speed

- Cruise speed and dash speed: Limited under normal ambient conditions by the

twin engine continuous power and / or transmission limits.

• Mission endurance

- Restricted by available fuel volume combined with reduced mission radius due to

reduced speed capability.

• Weapon fit

- Hellfire (need to maintain laser designator on target using nose-mounted TADS, or

rely on a third party (ground unit or Scout helicopter) for target designation)


180

- No Mast Mounted Sight

- No specific anti-helicopter capability

• Reliability & Maintainability

- Required MTBMF 40 hours; AH-64A specification 20 hours MTBMF

- Maintainability: Required 3 MMH/FH

• Mission System

- Significant changes in content and functionality required

- Includes nav, comms, ID, autopilot functionality and cockpit systems

• Control System technology

- GST assumes fly-by-wire or fly-by-light technology

• Radar cross-section

- Apache philosophy is more one of surviving being engaged, rather than avoiding

detection

Design Issues

• Transmission limits

- Matched to power available at the standard US Army design point (4,000 ft 95F)

- Increasing installed power (proposed in Ref 33) will be ineffective if transmission

ratings are not addressed, other than in extreme hot and high conditions

• Structure and dynamic system fatigue lives

- Fatigue life: Required 10,000 hr over 25 yr; AH-64A specified 4,500 hr over 15 yr.

- Lack of qualification data and different qualification approach for some critical

Components

• Manoeuvre capability

• Future growth

- The AH-64A Structural Design Weight of 14, 660 lb (6,649 kg) would be exceeded

at typical mission weights from entry into service.

- In service weight growth would impact manoeuvre limitations, OEI performance,

mission performance and fatigue lives of critical components.

12.1.5 Future Developments

MDHC were aware of a number of the issues raised and already had in hand, or planned,

improvements under the general title of MSIP – Multi-Stage Improvement Plan. These included:

• New mission system architecture with dual duplex 1553B databus arrangement

• New crew station design

• Enhanced AFCS modes

• Improved nav system

• Digital map display


181

• AAWWS (Airborne Adverse Weather Weapon System) mast mounted sensor

MDHC confirmed this latter sensor was a radar and at the time (1988) WHL assumed that it was

a target acquisition system for millimetric wave Hellfire.

MSIP was expected also to have reliability and support advantages due to a reduction in the

number of line replaceable units (LRUs) for the same functionality. In the main, the MSIP

improvements were realised in the AH-64D model which began formal development in 1990 and

entered service in the US Army in 1997.

The appearance of AH-64D Apache Longbow, with its long-range mast mounted target

acquisition sensor, overcame the specific concerns in relation to Apache’s vulnerability in direct

fire engagements and provided a fire and forget capability for the primary anti-armour weapon

without reliance on third party target designation.

12.2 A129 and A129 LAH

Procurement strategies resulting from the MoD Phase 1 Feasibility Study (completed in November

1984) strongly favoured examination of a developed version of the Agusta A129 “Mangusta”

(Figure 35) to meet the requirements of GST3971. This proposal was known at the time as the

A129 Mk2, with MoD referring to the existing Italian aircraft as the A129 Mk1.

Figure 35 The British Army initially favoured a Light Attack Helicopter and regarded the

Agusta A129 as offering good potential combined with favourable collaborative opportunities.

They later preferred the higher weapon load and stand-off capabilities of the AH-64D Apache


182

In reviewing the A129 Mk1, Ref 55 says:

• “The first prototype flew in September 1983, the second has recently joined the flight

test programme … Its principal features are that it is a small, light (3.8 tonnes) tandem

seater powered by twin Rolls-Royce Gem engines. It has … a 1553B databus, multi-

function cockpit displays, and mechanical controls for the main rotor, with fly-by-wire

back-up together with wholly fly-by-wire tail rotor controls. It will employ the American

IHADS (Integrated Helmet and Display System) (and nose-mounted PNVS … and carry 8

TOW, unguided rockets, or a mix of both.”

• “Less than a year ago it was the accepted wisdom in the UK (and still is in France and

Germany) that the A129 was a ‘Mickey Mouse’ aeroplane employing 1970s technology.

From the brief description above, it will be seen that this is far from being the case; in its

airframe at the least the A129 is the most advanced European helicopter flying today or

planned to fly for some years. … The main rotor shaft has been designed from the outset to

accept a mast-mounted sight in due course, and rotor controls are contained within a

protective steel outer tube.”

Recognising that the initial version could not meet all the GST requirements, Agusta proposed a

developed variant, to be powered either by a single RTM 322 or twin Rolls-Royce Gem 60

engines. There were concerns about the ability to contain weight growth, with the MoD

commenting:

• “One of the most important features of the single-engine solution is that it mitigates the

increase in mission weight in moving to the Mk2 version.”

The mission weight increase was due to the incorporation of the significantly heavier TRIGAT

weapon system, including its associated mast-mounted sight. The sensitivity of the MoD to all-

up weight is indicated by the following statement:

• “UK specialists estimate that the mass of the single-engine aircraft could be contained

at some 4,200 – 4,300 kg [9,259 – 9,480 lb], but that there is a real possibility of the twin

Gem engine version’s mass exceeding the Important 4,500 kg [9,920 lb] threshold … tight

control of weight would remain very important in an A129 Mk2 programme. ”

The UK were also concerned about the choice of the Gem 60 for the twin-engine aircraft:

• “We doubt the wisdom of proceeding into the next century with the 1960s technology

Gem.” On the other hand, the Italian Army “still has some residual doubts about the

survivability aspects of a single engine solution and we and the Italian MoD agree that, if a

collaborative A129 Mk2 programme is decided upon a first priority would be to resolve the

question of engine choice.”

Collaboration proposals were also encouraging:

• “Both the Italian MoD and Agusta have indicated that they would welcome

collaboration with the UK on the development of the A129 Mk2. In principle they would be

prepared to accept equal sharing of costs and work on the project overall …”

The major recommendation of the MoD Phase 1 Feasibility Study was therefore that:


183

• “A decision in principle be taken to proceed with an Anglo-Italian collaborative

development of the A129 Mk2 on a stage-by-stage basis. An early objective would be to

reach agreement with Italy on the choice of engine(s).” (56)

The contemporary expectation that such a study would follow closely on from completion of the

MoD Feasibility paper (in November 1984) was frustrated, not least by UK and Italian

participation in the NH90 FPDS and the political and industrial fall-out from the ‘Westland

Affair’.

The actual programme objectives and timescales are summed up in Reference 57.

In the event, it was September 1986 before a first Memorandum of Understanding was agreed by

the Ministries of Defence of Italy, the United Kingdom, the Netherlands and Spain concerning:

"the principles and general arrangements governing a Joint Project for the feasibility,

development, production and support of the A129 Light Attack Helicopter".

At the same time an Intercompany Agreement between Agusta, Westland, Fokker and CASA was

completed relating to the A129 Light Attack Helicopter. In October 1986 a second Memorandum

of Understanding was signed by the above Ministries of Defence concerning:

“a feasibility and cost definition of the A129 LAH Light Attack Helicopter”.

In November 1986 the Industries of the four countries, (Agusta 38%, Westland 38%, Fokker

19%, CASA 5%) formed a Joint Venture Company named the Joint European Helicopter (JEH)

Company and based in Italy (Rome).

The Al29LAH feasibility and cost definition study programme was constituted in two subphases:

1A and 1B.

1A was a feasibility phase, during which Industry was asked to assess how the Joint Staff

Target may best be met, using the A129 as a datum, followed by an assessment of the results

of this study by the four Governments.

1B was set aside to establish programme costs for the weapon system defined by Phase 1.

The programme started on the 1st June 1987 and, as required by the Statement of Work, Industries

assessed the possibility of deriving from the A129 a small, light and agile helicopter employing a

third generation anti -tank missile, to meet the requirements of the four countries. The first study

report was submitted on schedule on the 31st May 1988.

Although this programme went ahead, the attitude of the User community had notably cooled (35)

with respect to A129 LAH – not least due to the fact that two and a half years had passed between

the completion of the MoD Phase 1 Feasibility Study and the start of the A129 LAH FCDS.

The feeling was also growing that A129 LAH would struggle to meet the requirements and that

the User community would rather have Apache, than lose further time studying options that were

considered unlikely to be successful.


184

Close working relationships had already been formed at all levels between the Industrial partners

during the NH90 Feasibility and Pre-Definition Study (until the UK withdrew from that

programme in early 1987): many of the same staffs were involved in both activities and Dr Smith

served on the configuration teams for both programmes.

Dr Smith was appointed Joint Technical Coordinator on the A129 LAH project, managing all the

UK technical input and working with his Agusta colleague Santino ‘Tino’ Pancotti, who was

supported by Massimo Feretti. Mr Graham was the lead for the Mission Systems team on

A129LAH, having previously represented Westland on the NH90 Mission Systems Team, with

particular responsibility for defining the ASW fit. As with the NH90 programme, this study was

conducted in a highly collaborative spirit, although as it progressed, it became clear that the

emphasis on a Light Attack Helicopter was waning as far as MoD was concerned.

The study of A129 LAH did not result in a successful programme to equip the armies of Italy, the

UK, Netherlands and Spain with an attack helicopter weapon system. However, the A129 LAH

study output was influential in the later definition of the five-blade A129 International. A full-

scale mock-up was built (Figure 36).

Interestingly, there was no study of a single engine solution (as previously anticipated) and the

Phase 1A outcome described an aircraft based around twin LHTEC T800 engines, with either a

four blade rotor using BERP technology, or a five-blade rotor of Agusta design.

The A129 LAH study contemplated anti-armour and anti-air (or at least anti-helicopter) roles. It

was concluded that A129 LAH was not suited to performing these tasks simultaneously but that

the overall mission could be met with a mix of aircraft, some carrying anti-armour weapons,

Figure 36 Although initially strongly favoured, the four-nation collaborative study of

A129LAH did not begin until June 1987, by which time the British user’s enthusiasm was

cooling in favour of the evolving Apache platform. This is the full-scale mock-up of the

A129LAH solution


185

others equipped with Matra Mistral weapons for the Scout - Escort role. The systems fit for the

aircraft was comprehensive, fully supportive of all-weather day/night operations in a hostile

environment and built around a redundant fibre optic data bus architecture.

Following completion of Phase 2 the Governmental position was clarified as accepting (58) the

feasibility of an A129 LAH based on the A129, but noting that ‘development of a solution that

would meet the requirements of all four nations would not be economic’. Consequently, ‘the

Governments concerned have decided not to proceed with an LAH development’. All

collaborative work on the A129 LAH ceased with this announcement.

A slightly different perspective on this is put forward in (35) where it is made clear that the Army

were unsupportive of the A129 LAH study from the outset, but saw that going along with it

would inevitably lead to the rejection of A129, while opening the door (and a funding stream) for

the ultimate purchase of Apache.

As Dorman states ‘by acquiescing, the funding line for a new attack helicopter was opened in the

LTCs (Long-Term Costings), which could be re-earmarked for the Apache when, as expected, the

feasibility study confirmed the Army’s conclusions about the A129’.

12.3 PAH-2 / HAC3G Tiger

The MoD conducted discussions in October 1984 (60) to ascertain the status and capability of the

aircraft being developed by the Franco-German PAH-2/HAP/HAC3G Programme. The UK

interest was solely in the French HAC3G (Hélicoptère Anti Char Troisième Generation), which

was planned to use the TRIGAT LR and its associated mast-mounted sight.

“Of the three versions, it is HAC3G which has formed the basis of our discussions with

Germany and France: HAP is not intended for the same role as GST3971, and PAH-2 is in

our judgement a seriously flawed concept. HAC3G, at least, meets GST3971 in its ISD, in

being designed from the outset to carry up to 8 TRIGAT … and in having night/bad

weather capability combined with a mast mounted sight. However, … it fails to meet the

GST in terms of airborne performance.” (Reference 33 para 18)

It is fair to say that the MoD did not view this programme favourably, partially because of the

aircraft’s characteristics, but significantly due to the somewhat hostile attitude of the parties

involved to UK involvement in the programme.

Without dwelling on it at length, it is worth repeating a few of the observations made in the MoD

Phase 1 Feasibility Report (61):

• HAC3G will have MMS and TRIGAT but

“falls short of GST3971 in terms of airborne performance in all areas at realistic mission

weights”.

• “The speeds and acceleration specified for HAC3G are already achieved by in-service

helicopters and offer no significant improvement for the future.”

• There would be a lack of UK influence over the specification.


186

“A particular point of concern to us, however, on PAH2/HAC3G is Eurocopter’s insistence

that WHL should act as subcontractor to MBB and Aerospatiale and would not be offered

full membership of the joint company. If this route were followed … Westland (and

possibly UK equipment suppliers also) would be reduced to a second-rate status

incompatible with their position as equal partners on EH101.”

• “ … the Franco/German decision to launch the development of PAH-2/HAC3G in May this

year was greeted by strong criticism from Italy at all levels of government and industry on

the grounds that the Franco-German project represented an unnecessary duplication of an

existing European programme, contrary to the 1978 declaration, and this hostility has been

maintained subsequently.” and “… a decision in favour of PAH-2/HAC3G would

undoubtedly incur the opprobrium of Italy and could very well prove very damaging to the

chances for the success of EH101.”

• Consequently, it was recommended

“That France and Germany be informed as soon as possible that we do not wish to proceed

with participation in their PAH-2/HAC3G programme.”

The PAH-2/HAC3G development programme continued and, in parallel, the industrial parties

worked together on the NH90 FPDS, up to the point of UK withdrawal in 1987. By 1988, the

A129 LAH four nation study programme was drawing to a conclusion and it was clear that UK

MoD were working toward an attack helicopter procurement competition.

During this period, Eurocopter became increasingly interested in competing for the UK Attack

Helicopter requirement with a version of their Eurocopter Tiger helicopter. This resulted in a

joint assessment of the Eurocopter Tiger, with assistance being provided by Westland (Dr Smith)

in the preparation of an unsolicited proposal to UK MoD. Informal feedback from FS (RW)

indicated that this had been seen as both useful and helpful.

Eurocopter subsequently teamed with British Aerospace to offer Tiger during the competitive

procurement phase of the UK Attack Helicopter programme (Figure 37).


187

13. AH-64D and AH-64E 13.1 AH-64D

As described in section 12.1, MDHC had indicated (during the initial visit by Smith and

Goddard) that there were plans to significantly develop the AH-64A system under the MSIP

programme.

In 1988 the proposed enhancements were yet to be committed but what was to emerge as the “D”

Model Apache was to largely show compliance to the Operator’s LAH vision of the late 1980s.

Concerns regarding use of Apache in the direct fire mission were resolved by the introduction of

a mast mounted radar able to rapidly locate and classify targets with minimal exposure from

cover and at ranges that could not be matched by known air defence.

The introduction of the radio frequency AGM-114L Hellfire missile permitted target engagement

from behind cover without a reliance on third party designation and data link supported co-

operation between aircraft served to manage what was otherwise a blind engagement. In this

context the size and radar cross section of the Apache was of much less concern: the vital

requirement to survive in a hostile, non-permissive, environment had been met by means not

envisaged by the authors of GST 3971.

Figure 37 The Franco-German Eurocopter Tiger was investigated by the British Army,

who felt that the participating Nations were initially offering unfavourable collaborative terms

for UK Industry. Westland had only a limited involvement with this project, although it

remained a competitor for the UK AH contract


188

Development of the AH-64D was approved in 1990, with the first prototype flying in April 1992.

Deliveries of production Longbow Apache to the US Army began in March 1997. In accordance

with the inter-Company MoU signed in 1988 Westland teamed with MDHC to offer the AH64D

for the UK Attack Helicopter competition. The UK selected the WAH-64D in July 1995, with a

contract for 67 AH-64D being signed in 1996. The first 8 aircraft were built at Boeing and the

remaining 59 were assembled by Agusta Westland at Yeovil from Boeing-supplied kits.

The UK aircraft were to be fitted with the Rolls-Royce/Turbomeca RTM 322 engines and was

equipped with a UK specific high-performance defensive aids suite. With the exception of minor

modifications, the WAH-64D which entered UK service in 2001 was otherwise common to the

US Army aircraft (Figure 38).

13.2 AH-64E

In July 2016, the UK Government decided to switch to an all AH-64E fleet. The Government

statement (62) referred to this purchase throughout as a ‘new fleet’ with sample quotes including:

“The new helicopter’s improved computing capacity and updated sensors means the new

fleet will also be receptive to upgrades in the future, ensuring it remains at the cutting-edge

of technology.

Figure 38 The Boeing AH-64D with Longbow mast-mounted radar and radio frequency

AGM-114L Hellfire missile provides rapid target acquisition and long-range stand-off attack

capability. The majority of the 67 aircraft procured were assembled as WAH-64D by Westland

from US-supplied kits


189

The Apache has already proved its worth on operations in Libya and Afghanistan,

supporting UK and coalition troops, and this new model will give our pilots an attack

helicopter that is faster, more responsive and more capable.

The first UK helicopters are due off the US production line in early 2020 and will begin

entering service with the British Army in 2022.”

Later clarifications (63) in 2017 indicated the intention was to acquire a total of 50 aircraft and that

a first batch of 38 aircraft were placed under contract for remanufacture to AH-64E standard. It

was thought that an order for the final 12 aircraft would be placed in due course.

The new aircraft will feature GE T700-701D engines of increased power, together with increased

gearbox ratings, a composite main rotor blade, JTIDS (Link 16), the ability to control a UAV, full

IFR capability and an improved undercarriage. The Longbow radar will be upgraded to offer

overwater capability.

The GE T700-701D has a rating structure as follows:

• Contingency (2.5 min, one engine inoperative) 1,491 kW (2,000 hp)

• Maximum (10 min) 1,486 kW (1,994 hp)

• Intermediate (30 min) 1,418 kW (1,918 hp)

• Continuous 1,279 kW (1,716 hp)

The capability to be offered by the AH-64E fleet addresses to a large extent concerns expressed

earlier about power availability, transmission limits and mission system functionality.

A further clarification in March 2020 (64) confirmed that: the UK now has under contract all of

the planned fleet 50 of the Boeing AH-64E Apache attack helicopters. The additional 12 aircraft

are included in an on-going manufacturing programme that will integrate remanufacture of the

UK’s Apache with similar aircraft being upgraded for the US Army and other FMS customers.

Transition to a full UK AH-64E fleet is expected to be complete by around 2024 (Figure 39).


190

14. DISCUSSION

This paper reviews work at Westland Helicopters related to development of dedicated attack

helicopters. The early sections of the report provide some context for the work in terms of

contemporary MoD procurement processes (generally managed by the Rotorcraft activity within

RAE Materials & Structures Division, or by the FS(RW) area within MoD).

These organisations generated requests for conceptual, research and pre-feasibility studies and the

paper also describes the Westland Future Projects and Advanced Technology organisations that

were tasked to respond to these requests. These groups also supported any private venture

investigations requested by the Westland Helicopters senior management team.

14.1 Armed Attack Lynx projects

The initial effort to configure a dedicated armed attack helicopter centres on Lynx derivatives,

reported in Sections 4 and 5. The decision of the French Government not to proceed with the

Armed Escort Lynx derivative meant a reduction of some 150 aircraft in the planned programme

and a missed opportunity to develop a dedicated European attack helicopter design.

Figure 39 The UK Apache fleet is due to transition to the Boeing AH-64E, which had

greater power, enhanced mission capabilities and enhanced digital connectivity.

Photo US Department of Defense DVIDS image

Note: The appearance of U.S. Department of Defense (DoD) visual information does not

imply or constitute DoD endorsement.


191

This was damaging to Westland in terms of workshare and was widely regarded as against the

spirit of the Anglo-French helicopter agreement, particularly with the development of the

Dauphin series, which were seen to compete with the Lynx in some defence markets.

With the main Lynx programme established, a series of private venture proposals for two-seat

attack helicopters were generated, including “Wildcat”; WHL/VFW-Fokker P277 (aimed at the

Franco-German PAH-2 requirement); and “Warrior” – an advanced concept, based on a co-axial

lift offset rotor with lift and thrust compounding.

The final private venture Lynx derivative was Lynx 3, which progressed as far as a flying

prototype, but did not attract any sales.

The failure of these programmes was primarily due to their not being proposed against a clear

market demand – they were industrial solutions looking for a customer. The exception could be

in the case of the WHL/VFW-Fokker P277, where the problem was more a failure to realise that

the existence of the PAH-2/HAP/HAC3G programme would be the catalyst for France and

Germany to rationalise their helicopter industries by bringing Aerospatiale and MBB into

Eurocopter (now Airbus Helicopters).

In this case, by the time the P277 proposal emerged the Franco-German direction of travel was

beginning to be established, although it was January 1992 before Eurocopter formally came into

being.

14.2 Procurement Aspects

Before moving on to discuss other helicopter projects, it seems worthwhile to consider some

procurement aspects. To assist in this discussion, Figure 40 provides an indication of the number

of relevant technical activities that Westland were engaged in over this period and the

relationships between them and an indication of their timing.

The key question here is to understand how an operator that had formally expressed serious

concerns about Apache, due to its large size and signatures, its apparent need for a supporting

Scout helicopter, and its potentially damaging effects on European collaboration in the helicopter

sector, nevertheless ended up buying exactly that solution. This is all the more intriguing, given

that the Army’s Phase 1 Feasibility Study (32) came down very heavily in favour of examining

developments of the Agusta A129.

Two aspects that are worth examining are (i) the factors shaping the conclusions of the MoD

Study Group Report and (ii) the reasons for the delay between the issuing of that report in

November 1984 and the commencement of the four-nation assessment of the A129LAH in July

1987.

14.2.1 Army Phase 1 Feasibility Study

The Phase 1 Feasibility Study stands out as being primarily a study of potential solutions, with

explicit consideration of the commercial and industrial implications of those solutions. This was

consistent with the contemporary approach though dramatically different from current practice

which is initially focussed on capability needs and is solution agnostic.


192

Thus, the Army Phase 1 Feasibility Study was specifically solution-focused and explicitly

reviewed political, commercial, industrial and collaborative considerations as an integral part of

the assessment. It also was expressing firm views in respect of the anticipated maximum all up

weight of the expected solution. “We have refined our requirements around an essentially light

helicopter (4/5 tonnes) …”. Reference is also made under the A129 discussion to “the 4,500 kg

[9,921 lb] threshold”.

There appears also to have been a lack of communication between various MoD departments and

the Army, in that FS/RW was continuing to fund Westland to generate WG.45 as a compliant

GST3971 solution at the same time as the Army was deciding that there was no point evaluating

it, as Westland was judged unable to deliver it in parallel to the EH101 programme.

Had WG.45 been evaluated, the Army's expectation of an LAH at 4 - 5 tonnes might have been

challenged earlier. Figure 26 shows that a 'Conventional' GST3971 compliant design weights

around 13,000 lb (5.9 tonnes), compared with the AH-64A Primary Mission Gross Weight of

14,445 lb (6.5 tonnes) and structural design weight of 6,649 kg (14,660 lb). The predicted weight

of WG.45 (close to 6 tonnes), designed from the outset to meet GST3971 requirements, could

have given pause for thought over the viability of the proposed A129-based solution.

The Phase 1 Feasibility Study was undoubtedly influenced from the outset by the political

environment. The Secretary of State for Defence was Michael Heseltine, who was known to

favour a solution based on European collaboration, consistent with the 1978 Ministerial

Declaration of Principles on Helicopter Collaboration.

At this time, the Army was very careful to avoid going against the 1978 Declaration, not only as a

result of the political mood, but also potentially influenced by the damaging effect on relationships

that had been caused by the earlier decision by the French Government not to proceed with the

full Lynx programme.


193

Figure 40 Relationships between Westland Attack Helicopter projects and other activities

discussed in this paper


194

Without reiterating the entire discussion of the Phase 1 Feasibility Study presented above, its key

findings are summarised in the following table:

Candidate Solution Considerations

WG.44 WG.44 was close to meeting the emerging performance requirements

with a number of attractive operational features. Significant development

risk in a number of areas. Regarded as an expensive option as weapon

system costs were not included in WHL estimates.

Concerns around industrial capacity; and the legitimacy of a national

procurement approach, given the 1978 Ministerial Declaration.

Given Westland’s dependence upon the success of EH101 for their

future commercial strength, we conclude that it would be most unwise to

add a further development burden of the magnitude of WG.44 to the

company’s workload. To do so would in our view be to prejudice the

success of both

WG.45 WG.45 was intended as a benchmark setting out the company’s view of

the kind of helicopter that would be necessary to meet the performance

parameters of GST3971 in all respects. The primary Army concerns

were Industrial capacity and the 1978 Ministerial Declaration.

The Army documentation indicates that “Westland themselves have

made it clear that they would not wish WG.45 to be pursued, because

they do not possess the engineering capacity to develop it alongside

EH101”. WG.45 was excluded from further assessment.

AH-64A Concerns over operational concept, size and signatures: “AH64 in its

present form is not a survivable direct-fire weapon system and to modify

it to accept TRIGAT LR and MMS would be very expensive. A US

purchase would cause us severe difficulties with our European partners.”

Flight performance and endurance were criticised, together for the need

to operate with a Scout helicopter in the indirect fire role.

A129 Development required to add TRIGAT LR and a mast-mounted sight.

Favourable collaborative environment: “Both the Italian MoD and

Agusta have indicated that they would welcome collaboration with the

UK on the development of the A129 Mk2. In principle they would be

prepared to accept equal sharing of costs and work on the project overall

…”

The major recommendation of the Phase I Feasibility Study was that: a

decision in principle be taken to proceed with an Anglo-Italian

collaborative development of the A129 Mk2 … This was undoubtedly

influenced by the existing collaboration between Westland and Agusta in

respect of the EH101 development. The ability of an A129 Mk2 to meet

GST 3971 requirements at 4.5 tonnes appears not to have been examined

in depth.

PAH-2 The UK interest was solely in the French HAC3G, which was planned to

use the TRIGAT LR and its associated mast-mounted sight. It is fair to

say that the MoD did not view this programme favourably, partially

because of the aircraft’s flight performance, but significantly due to the

somewhat hostile attitude of the parties involved to UK involvement in

the programme, combined with a determination not to allow WHL to

become an equal partner in the programme.


195

The above table shows that the Army’s view of the candidate solutions in late 1984 was

dominated by collaborative and industrial considerations. Operational issues were chiefly

restricted to the vulnerability of the AH-64A in the direct fire role and its reliance on a Scout

helicopter in the indirect fire role. The performance of the HAC3G was also criticised.

The close scrutiny of cost, risk and weight applied to the WG.44 option does not appear to have

been applied to the other candidate solutions (other than in respect of potential modifications to

AH-64A to accommodate TRIGAT LR, a mast-mounted sight and Rolls-Royce engines).

The Phase 1 Feasibility Study conclusions therefore appear to have been driven by considerations

that, in today’s procurement environment, would not have fallen within the remit of the end user

to determine.

14.2.2 Delay prior to the start of the A129LAH Study

Support for European collaboration was ultimately responsible for the Army’s Phase 1 Feasibility

Study’s recommendation of November 1984 for a detailed study of what was then termed A129 Mk 2.

During the early 1980s, a NATO Industrial Advisory Group (NIAG) had conducted a pre-

feasibility study, looking at the practicality of a common medium size helicopter to meet the

maritime and land-based support helicopter needs of multiple European nations. This study led

to the decision of five nations (including Italy and the UK) to launch a Feasibility and Pre-

Definition Study (FPDS) for the NH90 “NATO Helicopter for the 1990s”.

Starting in September of 1985 this work continued until December of the following year and it

was the prime focus for the future projects personnel working for Westland and Agusta. Neither

Westland nor Agusta had sufficient experienced preliminary design/future projects personnel to

support the NH90 FPDS and the proposed A129 Mk2 study simultaneously.

Consequently, the latter study was put on hold in favour of the NH90 FPDS – a programme that

produced a helicopter that is in service with thirteen nations, with more than 400 aircraft having

been built out of the more than 500 ordered.

Following the 1986 Westland crisis, on 21st February 1987, the British government informed

Westland and its partners that the UK was withdrawing from the NH90 programme.

The intrusion of this major study had necessarily delayed the evaluation of the potential of a

development of the Agusta A129 in meeting the requirements of GST 3971. The withdrawal of

the UK from NH90 freed up resources for a return to Attack Helicopter studies.

The Army/MoD preference for A129 Mk2 had been based partly on a political desire for a

solution based on European collaboration, partly on its design philosophy and technology, partly

on the favourable collaborative terms offered to the UK, and on a desire to strengthen the existing

relationships between Agusta and Westland resulting from the EH101 programme.

The collaborative study of development of the Agusta A129 (with the UK, Italy, Spain and the

Netherlands) did not begin until June 1987. The political backdrop had changed, with less

emphasis on Europe and a growing interest in off-the-shelf solutions.

By the end of the A129 LAH study, it was clear that the emphasis on a Light Attack Helicopter

was waning as far as the UK MoD was concerned. This was consistent with the results of the

study, which made it clear that substantial development would be required and that it might be


196

necessary to separate anti-armour and escort capabilities between aircraft with different weapons

fits.

In November 1990, the Government announced that while development of the A129 was feasible,

“development of a solution that would meet the requirements of all four nations would not

be economic.”

14.3 Reconsideration of Apache

At the same time, the evolutionary path for the AH-64 (into the AH-64D Longbow Apache) was

starting to emerge. This was to lead to a major enhancement of the installed avionic systems

functionality, closing what was previously a significant gap to the aspiration described by GST

3971.

In particular a mast-mounted radar for target acquisition, combined with long-range radio

frequency AGM-114L Hellfire missiles was to be a key feature of the AH-64D configuration.

This permitted target engagement from behind cover without a reliance on third party

designation; data link supported co-operation between aircraft served to manage what was

otherwise a blind engagement.

The size and radar cross section of the Apache was now of much less concern: the vital

requirement to survive in a hostile, non-permissive, environment had been met in a manner that

was not envisaged by the authors of GST 3971 in 1984.

14.4 Procurement Competition

The path was now clear for MoD(PE) to run a procurement competition, seeking nominally off-

the-shelf solutions to their requirements.

The main contenders for this procurement were the Bell AH-1W Hueycobra, the Eurocopter

Tiger, the Denel Rooivalk, the MDHC (now Boeing) AH-64D and the Agusta A129.

A decision in favour of the AH-64D was announced in July 1995. The first Army Air Corps

Apache Regiment was declared fully operational in May 2005.

14.5 The Contribution of Westland’s Advanced Engineering Team

The 1980 reorganisation of Westland Helicopters Future Projects Activity as part of Advanced

Engineering and alongside Advanced Technology resulted in a more focused activity that took

account of both company requirements and the content of the MoD Corporate and Applied

Research Programmes undertaken at RAE Farnborough and Bedford.

Funded pre-feasibility and technology characterisation studies were also conducted to inform

customer thinking in terms of future requirements. The broad range of work undertaken included

work on advanced concepts, consideration of design to survive in future threat environments and

the characterisation of future technologies (such as advanced gearboxes, digital systems

architectures, materials and structures, and the benefits of rotor blade enhancements with

distributed aerofoil sections and tip planforms.


197

The results of these analyses and data from other test programmes, such as the Lynx BERP 3

manoeuvre trials, were fed into design tools, including the helicopter design synthesis tool

developed within Future Projects and applied to the studies of both WG.45 and the NH90

configuration definition.

Investigations whose outputs were fed into the Attack Helicopter designs included the examination

of twin tail rotors with a view to increasing low altitude agility and improving battle damage

tolerance.

Work carried out separately on remotely piloted helicopter concepts, led to a specific emphasis

on the reduction of radar and IR detectable signatures, which was influential in the design of the

WG.44, WG.45 and WG.47 projects. A funded study of a Light Battlefield helicopter against

FINABEL requirements was the first study where the use of shaped canopy transparencies,

specifically designed to minimise glint and specular reflection, particularly at lower sun angles,

was proposed.

The WG.44 project sought to use the Lynx dynamic system combined with a range of

technologies that were under investigation or development within Advanced Engineering. Key

features incorporated in this design for the first time included a shaped fuselage and internal

weapons carriage to reduce the helicopter’s Radar Cross-Section (RCS) and drag.

WG.44 was criticised as likely to be too risky. In part, this was because its study was formulated

as a response to a question along the lines of “What could you do by combining the Lynx dynamic

system with the emerging results from the company’s Advanced Technology programme”. It was

not realised at the time – the Army Phase 1 Feasibility Study, being conducted “behind closed

doors” – that this proposal was going to be evaluated as a potential solution to a set of requirements

that Westland had not yet seen.

Had this context been known it is likely that some account would have been taken of the actual

Technology Readiness Levels of certain systems, significantly reducing the development risk of

the design. At this stage, Westland also had no exposure to the TRIGAT LR programme and

were not in a position to account for its development or supply costs (this objection would have

applied equally to all the other helicopter options examined).

Given that the TRIGAT LR development was itself part of a collaborative programme, the

weapon system and mast mounted sight development would have been funded by that

programme (with the UK being responsible for a 22% share of these costs). It seems likely that

the weapons, system electronics and mast-mounted sight (MMS) would have been supplied as

Government Furnished Equipment (GFE) to any of the helicopter options that integrated this

system. Consequently, the only cost aspects that should have been accounted for by WG.44

would have been for the integration of that (as yet undefined) system.

WG.44 had been designed prior to the availability of early drafts of the GST 3971 requirement.

WG.45, on the other hand, arose as a result of a funded study to explore a compliant low

signature solution against the GST3971. Trade-offs associated with WG.45 were examined using

the Future Projects’ Design Synthesis tool. The Design Synthesis tool was also influential in

shaping Westland’s input to the NH90 Configuration Team during the NH90 FPDS.


198

WG.45 was developed with knowledge of the GST 3971 and was able to investigate the

sensitivity of the design to some of those requirements. WHL had previously signed an MoU

with MDHC to offer AH-64 to the UK should this option emerge and there was therefore no push

from the company to promote the merits of WG.45. Taken with the view that Westland lacked

the engineering resource to develop a new design in parallel to EH101, the Army dismissed the

WG.45 from further consideration.

Because the Army did not analyse WG.45, they failed to realise/accept that the GST3971 target

with its 2.5 hour mission with reserves and significant high speed manoeuvre requirements

(added to the mass of the complete TRIGAT system and a comprehensive mission system) was

never going to be 4 – 4.5 tonne Light Attack Helicopter.

WG.47 (1986) arose from a company-funded activity to further refine an Attack Helicopter

design driven by minimisation of detectable signatures. Versions were examined with single and

twin tail rotors and with both engine exhausts directed to one side of the helicopter to be carried

away from the fuselage structure by the swirl within the rotor wake. This feature has recently re-

emerged (October 2019) in the Bell 360 Invictus proposal for the US Army FARA competition.

WG.47 was broadly successful as a concept, with considerable learning achieved. This was

captured in a Design Guide(46) but these results were never used, mainly because, by then, the

Attack Helicopter competition was in full swing, with the stated aspiration of procuring an ‘off-

the-shelf’ design.

14.6 Westland Advanced Engineering Success Factors and achievements

An Advanced Engineering organisation was created to respond coherently to:

- Customer and company requirements in terms of technology assessment and development

- Design and develop tools for concept generation and weight and performance estimation at

pre-feasibility and feasibility level, including the assessment of novel concepts

- Having familiarity with signature reduction techniques, drawing on remotely piloted

helicopter projects and cross-party discussions in AVSRAG

The departmental achievements associated with Attack Helicopter studies include the following:

• Scheming of shaped fuselage attack helicopters with internal weapons carriage

• Definition low glint canopy geometries

• Definition of an advanced compact main gearbox the Advanced Engineering Gearbox, or

AEG

• Significant research and development work on active control systems

• Developmental activity on helicopter vibration control using Active Control of Structural

Response (ACSR), as implemented on the AW101 Merlin

• Proposal to use twin tail rotors to enhance agility

• Work with Rolls-Royce on advanced engine IR suppression techniques

• Proposal to direct all system exhausts to one side to be carried away from the aircraft

fuselage surfaces by rotor wake swirl in the hover

• Adoption of many (but not all) of the design features to reduce signatures subsequently

seen on F-117 and RAH-66 Comanche.


199

• Anticipation by some 30 years of features now proposed for US FARA projects such as

Bell Invictus.

15. CONCLUSIONS

This paper reviews efforts made by Westland Helicopters related to dedicated Attack Helicopter

studies, including both company-funded and MoD-funded activities.

As indicated by the introductory remarks, it would be easy to think that Westland’s efforts were

limited to adapting the Army Lynx for anti-armour operations and assembling WAH-64 Apache

aircraft from kits manufactured by Boeing in Mesa, Arizona.

This paper, however, demonstrates that there were sustained efforts from within the Westland

Engineering and Future Projects teams to develop dedicated attack helicopters, initially based on

Lynx and, from around 1980, new designs based on a co-ordinated technology programme

drawing upon a mix of company and official funding.

This latter activity developed several novel design features driven by a desire to minimise

detectable signatures, some of which are only now starting to appear on concepts elsewhere, such

as the Bell Invictus FARA contender.

The final phase of activity included participation in the four-nation A129 LAH study and detailed

assessment of both the MDHC (Boeing) AH-64A Apache and the Eurocopter PAH-2 / HAC-3G

against UK Requirements.

Recently available documents released from the National Archive give insight into parallel

analysis and thinking in the MoD and User communities that sheds interesting light on the

success and failure of some of these efforts.

Selected conclusions are listed below, grouped against the main phases of activity:

15.1 Lynx Developments

When Lynx became part of the Anglo/French helicopter programme a three-man Armed Escort

version was anticipated against a French requirement. The French decision not to proceed

removed a significant number of aircraft from the programme and was a missed opportunity to

develop a European dedicated attack helicopter design.

The Army Air Corps adapted their Utility Lynx to provide an anti-armour capability based on the

Hughes TOW wire-guided missile.

Further attempts to produce a dedicated attack version of Lynx (“Wildcat” and P277) as well as a

multi-role battlefield derivative, Lynx 3, were unsuccessful, due to lack of a driving customer

requirement and/or the limited development funds available.


200

15.2 Westland Organisational Aspects

Westland’s formation of Advanced Engineering in October 1980 was well aligned with customer

activities, resulting in coherent activity and close working relationships.

Westland’s work on Remotely Piloted Helicopters and involvement in AVSRAG discussions led

to increasing familiarity with techniques to reduce radar and IR signatures.

Westland’s technology portfolio evolved to include advanced rotor systems (BERP), a high ratio

Advanced Engineering Gearbox, fibre optic Mil Std 1553B databus work aimed at a robust and

resilient data management architecture , novel transparency shapes to reduce glint, and twin tail

rotors to increase agility and provide a degree of redundancy.

The creation of a helicopter design synthesis methodology allowed the rapid generation and

comparison of new concepts and made a significant contribution to the definition of the NH90

configuration during the UK’s participation in that project.

15.3 UK National Attack Helicopter proposals – WG.44, WG.45 and WG.47

Design of these options was driven by the MoD statement: “Survivability is of vital importance

on the high threat battlefield. The Group has come to the view that key features are a MMS and

the greatest possible reduction in visual, aural, radar and IR signatures; resistance to battle

damage; and speed and agility, both in the face of the ground threat and to enable the helicopter

to defend itself if attacked by enemy helicopters”.

WG.44 was derived using the output from the technology research and demonstration activities

conducted by Westland’s Advanced Engineering teams, combined with an emphasis on signature

reduction, including a shaped fuselage and retractable weapon carriage.

WG.45 drew on the WG.44 but was specifically directed to achieving full compliance with

GST3971.

WG.47 was a further evolution of WG.45, placing more emphasis on the minimisation of

detectable signatures, including high performance IR suppression, with both engine exhausts

being directed to the same side of the aircraft. It was not evaluated as an LAH candidate.

The MoD assessed the single engine WG.44 variant as broadly compliant with GST3971 but

considered that the technologies involved carried significant development risk, leading to cost

adjustments being applied to the figures submitted by Westland.

Most significantly, in respect of WG.45, the Phase 1 Feasibility Study Report indicates that

“Westland themselves have made it clear that they would not wish WG.45 to be pursued because

they do not possess the engineering capacity to develop it alongside EH101.”

As a result, the MoD Feasibility Study did not examine WG.45 further. However, because the

Army and MoD did not analyse WG.45, they failed to realise that the GST3971 target with its 2.5

hour mission with reserves and significant high speed manoeuvre requirements (added to the


201

mass of the complete TRIGAT system and a comprehensive mission system) was never going to

be satisfied by a “Light” Attack Helicopter.

Westland felt that WG.44 would be more cost effective than WG.45 but the MoD Feasibility

Study Report takes the view that, if Westland were unable to complete WG.45, the company

would also be unable to complete WG.44.

The report states “Given Westland’s dependence upon the success of EH101 …, we conclude that

it would be most unwise to add a further development burden of the magnitude of WG.44 to the

company’s workload. … We therefore believe that the overall effect of a national WG.44

development would be damaging to UK Industrial Interests.”

WG.47 anticipated several design avenues, subsequently revealed in platforms such as the F-117,

which were not publicly known at the time that WG.47 was being schemed.

The proposal to direct all cooled exhaust flows to one side of the helicopter in the direction of the

rotor’s rotation has only recently re-emerged in Bell’s Invictus proposal for the US FARA

programme.

15.4 MoD Phase 1 Feasibility Study

During 1984, the MoD and Army user conducted a review of options, reporting the outcome in

November 1984 in the report: GST3971: Report on Phase 1 Feasibility Study. The options

considered were PAH2/HAC3G, Agusta A129, UK National Development, and off-the-shelf

procurement (AH-64A or LHX).

The thrust of the report was heavily directed towards finding a European collaborative solution

for the UK LAH. This reflected political guidance and the 1978 Ministerial Declaration of

Principles on Helicopter Collaboration. A further consideration was that a UK national solution

ran the risk of slowing, or destabilising, the parallel EH101 programme.

Consequently, the report was opposed to both a UK national solution and an off-the-shelf

purchase of AH-64A Apache (or LHX) from the United States.

The Feasibility Study recommended that a decision in principle be taken to proceed with an

Anglo-Italian collaborative development of the A129 Mk2 on a stage-by-stage basis.

The Phase 1 Feasibility Study was conducted ’behind closed doors’ with the result that the

Westland technical team was not aware that (for example) WG.44 would be assessed as a

candidate Attack Helicopter solution to a requirement that was not available to Westland at the

time this assessment took place.

A greater awareness of the context associated with the request for information that the company

received would have resulted in Westland offering a lower risk solution. One can anticipate that

this would have retained the shaped fuselage and internal weapon carriage to reduce signatures

and enhance performance, but would have excluded some of the higher risk technologies, such as

the Advanced Engineering Gearbox and active flight control system.


202

It is not entirely clear from the material in the National Archives, the extent to which MoD (PE)

personnel were aware of the scope of the Phase 1 Feasibility Study. It is clear, for example, that

FS/RW was continuing to fund Westland in completing the parallel study of WG.45 (43), after the

Army had decided to exclude this design from their evaluation.

The Study can also be criticised, when compared with more recent Capability focused assessments,

in that the end-user’s assessment was focused on specific design solutions, including consideration

of industrial and commercial aspects and the specification of preconceived weight limits, which

were ultimately incompatible with the Capability being sought.

As a result, the conclusion in favour of a development of the Agusta A129 proved to be

unattainable.

One further conclusion is that various European collaborative activities had a considerable

influence on the UK Attack Helicopter programme, examples being:

• the impact of EH101 on undermining a UK national attack helicopter solution;

• the failure of the French and German participants in the PAH2 programme to offer a

warmer welcome to the UK interest in their programme;

• the warm welcome from the Italians in respect of the Agusta A129, which seemed to

result in a rather unquestioning attitude in respect of the capability on offer; and, finally,

• the emergence of a real European medium helicopter programme (NH90) which mopped

up the available engineering resource at a point where the UK would have dearly liked to

launch its proposed study of A129 Mk2.

This truly represents a set of unintended consequences, all involving collaboration aspects,

arguably distorting the outcome of this activity.

15.5 AH-64A Assessments

Both UK MoD and Westland conducted assessments of AH-64A against UK requirements.

MoD’s conclusions were as follows:

It was felt that the large size and radar signature of Apache would render it vulnerable as the

whole helicopter would be exposed while laser designating its targets.

AH-64 was also considered expensive (particularly in the light of modifications required to fit

TRIGAT and its associated MMS) and that it would be hard to obtain significant UK workshare,

other than by a possible change of engine to the RTM 322.

A US purchase would cause “severe difficulties” with European partners.

There were a number of other non-compliances with the GST requirements, particularly in terms

of mission endurance, speed, manoeuvrability, mission and cockpit systems, and reliability and

maintainability.

Westland’s conclusions were as follows:

The flight performance of AH-64A was restricted by the combination of the T700 engine rating

structure and both single- and twin-engine transmission limits. Mission system functionality at


203

the A Model standard was significantly non-compliant with the GST requirements but that

planned upgrades under the MSIP activity would largely resolve these concerns.

A further point noted by Westland was that some qualification data for key dynamic components

was missing or had been derived using different standards than would normally apply in the UK.

15.6 Agusta A129 and A129 LAH

The Army/MoD preference for A129 Mk2 was based partly on a political desire for a solution

based on European collaboration, partly on its design philosophy and technology, partly on the

favourable collaborative terms offered to the UK, and on a desire to strengthen the existing

relationships between Agusta and Westland resulting from the EH101 programme.

The collaborative study of development of the Agusta A129 (with the UK, Italy, Spain and the

Netherlands) did not begin until June 1987.

By the end of the A129 LAH study, it was clear that the emphasis on a Light Attack Helicopter

was waning as far as the UK MoD was concerned.

In November 1990, the Government announced that while development of the A129 was feasible,

“development of a solution that would meet the requirements of all four nations would not

be economic.”

15.7 Eurocopter PAH-2 / HAC-3G

The MoD Phase 1 Feasibility Report is generally unfavourable in respect of PAH-2 / HAC-3G,

the main considerations being relatively poor performance, concerns about future mass growth,

and highly unfavourable collaborative terms offered for both the MoD and Westland Helicopters.

The Report recommended that

“France and Germany be informed as soon as possible that we do not wish to proceed with

participation in their PAH-2 / HAC-3G programme.”

Westland activity in relation to PAH-2 / HAC-3G was limited to assisting Eurocopter in preparing

a summary of its capability against UK requirements, to be provided to UK MoD (FS/RW).

15.8 Boeing AH-64D

The delay before the final procurement competition for the Attack Helicopter began meant that

AH-64D with mast mounted sensor, RF Hellfire and a substantial mission system upgrade over

the original A model standard could be offered for consideration in that competition.

There was a twelve-year period between the Army/MoD Phase 1 Feasibility Report

(recommending a staged approach to the joint Anglo Italian development of Agusta A129 Mk2)

and the eventual contract signature for the procurement of the AH-64D.

Concerns regarding use of Apache in the direct fire mission were resolved by the introduction of

a mast mounted radar on the AH-64D, able to rapidly locate and classify targets with minimal

exposure from cover and at ranges that could not be matched by known air defence.


204

The introduction of the radio frequency AGM-114L Hellfire missile permitted target engagement

from behind cover, without a reliance on third party designation, and data link co-operation

between aircraft served to manage what was otherwise a blind engagement.

In this context the size and radar cross section of the Apache was of much less concern: the vital

requirement to survive in a hostile, non-permissive, environment had been met by means not

envisaged by the authors of GST 3971.

The UK selected the WAH-64D in July 1995, with a contract for 67 AH-64D being signed in

1996. The first 8 aircraft were built at Boeing and the remaining 59 were assembled by Agusta

Westland at Yeovil from Boeing-supplied kits.

15.9 Boeing AH-64E

In July 2016, the UK Government decided to switch to an all AH-64E fleet and an order was

placed for 50 AH-64Es through the US Foreign Military Sales programme, these aircraft being

generated by upgrading the existing AgustaWestland-assembled AH-64Ds.

The new aircraft will feature GE T700-701D engines of increased power, together with increased

gearbox ratings, improved main rotor blades, JTIDS (Link 16), the ability to control a UAV, full

IFR capability and an improved undercarriage. The Longbow radar will be upgraded to offer

overwater capability.

The procurement of the AH-64E addresses to a large extent concerns expressed earlier about

Apache power availability, transmission limits and mission system functionality. Furthermore,

the procurement of this variant adds capability and increases interoperability with the US AH-

64E fleet.


205

List of Key Personnel

Westland / other Industry Users and Officials

Name Role or Post Name Role or Post

Fitzwilliams, OLL Chief Helicopter

Engineer (pre merger)

Barrett. Ian MoD FS(RW)

Hafner, Raoul Technical Director (post-

merger) ex-Bristol

Helicopter Division

Cansdale, Tim MoD FS(RW) after

Barrett

Austin, Reginald Head of Project Office

(post-merger). Later led

RPH activity

Jones, AF (Alan) RAE Head of Materials

& Structures Division

Speechley, John Engineering Director,

later Managing Director

Maj Gen A.H.

Farrar-Hockley,

DSO, MBE, MC

Director Combat

Development (Army)

Howell, David Head of Projects (near

term focus)

Major General Ian

Baker (in 1979)

Major General

L.A.W. New (in

1984)

Army: ACGS(OR)

Jupe, RJ (John) Head of Future Projects

to Oct 1980

St J Lytle, SW

(Simon)

Army: DDOR7

Smith, Ron

Chief Project

Engineer

(Airframes)

From Oct 1980, later

Chief Design Engineer

(LAH)

Porter, JA (John) MoD: DGA2

Roy, SD (Scott)

Chief Project

Engineer (Systems)

Head of Future Projects

(Systems) later MD

Aerosystems

International

Hyde Smith (Wilf) Army: SO1 CD(OR)

Balmford, DEH

(David)

Head of Advanced

Engineering

Goddard, PN (Phil) Head of Advanced

Technology

Graham, JP

(Jeremy)

Head of Avionics and

Systems Technology

post 1986

Wright, David Programme Manager

RPH

Jones, JP (Jeff) Research Director

Ciastula, Tadeusz

(Ted)

Chief Designer (Lynx)

Moss, John (Col,

retd)

WHL Military Advisory

Liaison Team


206

Waddy, John (Col,

retd)

WHL Military Advisory

Liaison Team

Case, Richard Chief Designer, later

Engineering Director,

later Managing Director

McMullan, Derek Chief Designer Lynx 3

Chapman, Paul Future Projects,

responsible for Design

Synthesis methodology

Pengelly, Mike Head of Avionics and

Systems Technology to

1986

Sergio, Genaro Agusta: General

Manager JEH

Pancotti, Santino

(Tino)

Agusta: Head of

Preliminary Design

Feretti, Massimo Agusta: Future Projects


207

References

1. Westland and the British Helicopter Industry, 1945-1960, page 88. Matthew Uttley. ISBN-

13 978-0714651941.

2. Light Tactical Helicopters WG.3 and WG.7. WHL Project Office Report No.3. McKinlay

and Davies. 1963.

3. Draft GSR 3335: Battlefield Utility Helicopter for use by the Army Air Corps, Oct 1964

4. WHL Project Office Report No. 23. A study to determine the feasibility of providing a

utility transport helicopter to GSR 3335 with an armed escort capability. Austin. April 1966

5. Notes of a meeting between WHL, UK MoD and Sud Aviation, Marignane, March 1966,

TL Ciastula

6. WHL Project Definition Study of WG13 Multi-Purpose Helicopter for Joint Anglo-French

Requirements - Armed Reconnaissance Version, TL Ciastula, TP173/1, May 1967

7. Westland WG13, Brochure B420-Issue 2, August 1968.

8. Briefing on Lynx WG13 March 1969 [The Anglo French WG.13 helicopter Design

Philosophy and Capabilities. Brochure 473, March 1969.]

9. Westland Preliminary Design Dept Note No 173, 1973 by A. Waddington

10. An outline of some present, proposed and possible helicopters. WHL Paper prepared for the

visit of Maj Gen A.H. Farrar-Hockley, DSO, MBE, MC, Director Combat Development

(Army). 27th February 1975.

11. Westland Armed Attack Lynx, June 1975. Brochure B.874

12. Westland VFW Fokker P277 Brochure (Document Reference not available)

13. Presentation by Westland helicopters Limited to Future Army helicopter Steering Group,

28th September, 1979.

14. The National Archive: File DEFE 70/476 Helicopter Future Service Requirements – The

Army’s Future Requirements

15. Ref 14: Reference to no Lynx replacement until ‘the late 1990s’: - Draft answer to

Parliamentary Question; Background Note to PQs 4878C, 4879C, 4880C

16. Ref 14: Westland presentation to FAHSG, 28th September 1979. Note post-meeting by Col

SMW Hickey, GS(OR)14, 22nd October 1979.

17. Lynx 3 Brochure Reference: Lynx and its Development. Paper presented to RAeS

Rotorcraft Section by D.J.McMullan, February 1983.

18. Lynx 3 for Germany: Army Lynx III for the Federal German Army, Brochure B1402, May

1981

19. Lynx3. The anti-armour helicopter with multi-role capability. November 1982. Brochure

B.1670


208

20. WHL Project Office Note No. 60, Diary Note on a visit to discuss requirements for

battlefield surveillance drone, Austin. September 1968.

21. Preliminary data on WR08 @ X-band, EMI 47000/SCW/DG. November 1978.

22. General Staff Target GST 3846 – basis for studies of unmanned air vehicles defining

Intelligence and Artillery Corps system requirements.

23. GST3846-Phoenix RPV Feasibility Study Report, SP.4972. September 1982.

24. Anti-submarine helicopter with co-axial supersonic rotor @ 25,000lbs WHL RP553 Final

Report March 1976

25. WG.37, Advanced Combat Helicopter, WHL RP 591. June 1978.

26. A study of the implications of high threat battlefield environments for the design of future

helicopters and their systems, Report prepared by WHL Advanced Technology (Avionics

& Systems), (Document Reference not available).

27. Twin Tail Rotor Patent Application UK Patent Application 7910385, 23rd March 1979

28. Multiple channel optical avionics data transmission networks, M. J. Kennet, Nov 1988

29. FINABEL 19.A.12, Basic data for the study of the military characteristics of the future light

combat helicopter, May 1983

30. Jupe low glint canopy patent application (GB8716557.7 14 July 1987)

31. The National Archives File DEFE/72/428: GST3971 – Light Attack Helicopter, 2 July

1984 First Draft

32. The National Archives DEFE 70 / 1458 Future Helicopters: Light Attack Helicopter

(LAH); General Staff Target (GST) 3971

33. Ref 32: - Report of the Study Group on the Light Attack Helicopter to GST 3971

34. Ref 33: Paras 4 to 8 - Summary of Requirements

35. Defence Under Thatcher (Southampton Studies in International Policy) by A. Dorman,

Palgrave Macmillan, 2002

36. Westland WG44 Light Attack Helicopter, Brochure B2075 September 1984

37. Phase 1 Pre-Feasibility Studies of LAH; WHL Report RB667, January 1984.

38. WG44 retractable weapons patent: GB2177668A Helicopter with missile supporting means

39. Ref 33: Paras 56-59, para 77 and Annex D - MoD comments on WG44

40. Ref 32: Loose Minute D/OR12/3/1/38/8 28 September 1984 – Operational Requirement

Assessment: Procurement options to meet GST3971 (LAH), SW St J Lytle, Col OR(12)

Avn, – Paras 27, 28 WG44/45 assessment

41. Ref 33: Para 55 – MoD comments on WG45

42. Ref 32: WG45 Notes of a meeting between WHL and MoD, 07/14/84. Ian Barrett FS/RW

43. WG45 Report - Phase 2 Pre-feasibility Studies of LAH; WHL Report RP679, April 1985


209

44. Ref 34: Paras 53, 102 – Industrial Implications of WG44

45. Joint Staff Target for A129 LAH. Official document derived from GST3971 against which

JEH studied A129LAH. (Document Reference not available)

46. An outline of a low signatures design handbook, Vols 1 and 2, June 1990

47. Ref 32: Brief by Hyde Smith SO1 CD(OR) ahead of a meeting (15/1/85) at Westland to

discuss WHL MoU on AH-64.

48. Ref 32: Telex to British Defence Staff Washington from DDOR7 7/12/84

49. Ref 32: JA Porter (DGA2) Digest to Phase 1 Feasibility Study Report (November 1984)

50. Ref 33: Paras 61-69 – Comments on AH-64A

51. Ref 33: Para 103 - Conclusions in respect of AH-64A

52. Ref 33: Annex D Paras D4.1 to D4.6 Assessment of AH-64A

53. Ref 32: Loose Minute D/OR12/3/1/38/8 30 September 1984 – Operational Requirement

Assessment: Procurement options to meet GST3971 (LAH); Paras 21-25 AH-64

Assessment

54. WHL Report: A Preliminary Assessment of AH-64A and Potential Developments against

the Joint Staff Target for LAH” RV Smith, 1st September 1988, LAH/RVS/SMH/0209.

55. Ref 33: Paras 30-54 – Comments on A129Mk1 and A129Mk2

56. Ref 33: Para 106 – Recommendation to collaborate with Italy on a staged development of

the A129Mk2.

57. The A129 LAH Project, Genaro Sergio, Joint European Helicopters, Paper 31, 15th

European Rotorcraft Forum, Sept 12-15th, 1989, Amsterdam.

58. Statement by the UK Government in relation to A129LAH, Hansard, 28 November 1990.

59. A129 Light Attack Helicopter Project Feasibility and Cost Definition Phase (Sub Phase 1A,

LAH.1A/JEH-001. May 1988. WHL Phase 1b report was issued in December of 1989.

60. Ref 31: DGA2 Report of meeting with French and German officials to discuss PAH-2 and

HAC3G, 19 October 1984

61. Ref 33: Paras 9-31, 93-94 and 108 - Comments on PAH-2 and HAC-3G and

recommendation to inform France and Germany that the UK does not wish to proceed with

participation in the PAH-2/HAC3G programme.

62. https://www.gov.uk/government/news/mod-orders-new-fleet-of-cutting-edge-apache-

helicopters-for-army AH-64E Reference, accessed 6th October 2020.

63. https://ukdefencejournal.org.uk/boeing-remanufacture-38-apache-helicopters-uk/ AH-64E

Reference, accessed 6th October 2020.

64. AH-64E Reference https://ukdefencejournal.org.uk/uk-confirm-order-of-fleet-of-50-apache-

ah-64e-attack-helicopters/

https://www.gov.uk/government/news/mod-orders-new-fleet-of-cutting-edge-apache-helicopters-for-army

https://www.gov.uk/government/news/mod-orders-new-fleet-of-cutting-edge-apache-helicopters-for-army

https://ukdefencejournal.org.uk/boeing-remanufacture-38-apache-helicopters-uk/

https://ukdefencejournal.org.uk/uk-confirm-order-of-fleet-of-50-apache-ah-64e-attack-helicopters/

https://ukdefencejournal.org.uk/uk-confirm-order-of-fleet-of-50-apache-ah-64e-attack-helicopters/


210

Acknowledgements

1) Chris Gibson for assistance in relation to files from The National Archives

2) Army Flying Museum for photograph of operationally deployed Lynx

3) Leonardo Helicopters for access to archives and review of content

4) Jim Smith for photograph F-117 at Nellis Air Force Base, April 1990

The authors

Jeremy Graham

Jeremy Graham joined Westland Helicopters in 1975. From 1983 he was assigned to work with

the Future Projects team on the avionic and weapon system aspects of the Light Attack

Helicopter. From 1986 he was appointed as the Head of Avionics and Systems Research and was

the company representative assigned to collaborative mission sensors and mission systems

engineering teams for NH-90 and the A129 Light Attack Helicopter respectively.

In 1989 he was seconded to EHI to lead the Project Definition study for EH101 to meet an RAF

requirement and then to lead the in-country engineering team bidding for the Canadian SAR

programme, based in Ottawa. In 1995 he was appointed as the lead engineer for the formal

Merlin Tactical Support Helicopter bid to the MoD, subsequently to become known as the HC3

Variant. He remained with this programme until the last aircraft was delivered.

In 2003 he was promoted to be the Chief Safety and Airworthiness Engineer for Westland

Helicopters and from 2007 the Head of System Reliability and Safety for the integrated

AgustaWestland engineering organisation. Finally, in 2012 he was assigned the role of Chief

Engineer for the out of production types, Sea King, Apache, Gazelle and Chinook.

Jeremy is a Chartered Engineer and a Fellow of the RAeS. He has been a past Chairman of the

RAeS Rotorcraft Group Committee, is a current member of the Medals and Awards Committee

and is Joint Chairperson of the RAeS Yeovil Branch. He has also served on the RAeS Learned

Society Board and Council

Dr RV Smith

Ron Smith joined Westland Helicopters Ltd in October 1975 in the Research Aerodynamics

department, supporting loads prediction modelling of the BERP rotor blade. From October 1980,

he was Westland’s Head of Future Projects. He was Joint Technical Coordinator of the four

nation A129LAH programme (being appointed Chief Design Engineer Light Attack Helicopter)

and was a member of the Configuration Team during the five nation NH90 Feasibility & Pre-

Definition Study.


211

He led the definition of UK’s national Attack Helicopter options and also conducted assessments

of the MDHC AH-64A and Eurocopter Tiger against UK requirements. In addition to technical

coordination of the A129LAH study, he has also conducted programme and risk evaluations of

the Denel Rooivalk.

Ron was Chairman of the RAeS Rotorcraft Group Committee from 1991 to 1993 and was a co-

opted member of the RAeS Council. He was a Member of the Design Committee of the

American Helicopter Society (AHS) and served on the AHS Technical Council. He is a current

member of the Vertical Flight Society (previously AHS). He is a member of the RAeS Historical

Group Committee and is a past winner of the RAeS Alan Marsh Award, a Chartered Engineer

and a Fellow of the RAeS.

Having retired at the end of 2012, Ron supports the BAE Systems Heritage team, and is a

published author of a dozen aircraft-related books, including the five-volume series British Built

Aircraft.

westland and the attack helicopter from lynx to apache

Documents