Douglas Barrie/LONDON

LIKE MOST OF its equivalents, the UK Ministry of Defence (MoD) likes to flatly deny the existence of sensitive programmes - rather appositely in the case of stealth projects

Nevertheless, the inadvertent disclosure of its High Agility Low Observability (HALO) programme during an unclassified conference in the UK is the strongest evidence yet of the UK's intention of maintaining a development effort on a third-generation balanced-stealth strike aircraft independent of the USA (Flight International, 1-7 November).

The HALO project is a precursor to what is dubbed "EAP Mk 2", the original Experimental Aircraft Programme having been the technology testbed for the Eurofighter 2000. The HALO programme feeds into the requirement for a Future Offensive Aircraft (FOA) to meet Staff Target (AIR) 425 for a replacement for the Royal Air Force's Panavia Tornado GR1/4 strike aircraft.

An in-service date of 2013 is now projected for the FOA. The HALO programme will run up until the end of this decade, to be followed by the EAP Mk2 project. That demonstrator programme is intended to run from around 2000 to 2006.

What constitutes the HALO programme is not yet known, but it would appear that it is aimed at producing flyable hardware.

British Aerospace, which has invested heavily in technologies related to low-observables, refuses to discuss its work on the FOA, although it has shown several concept designs for a third-generation strike aircraft. These show an emphasis on wing-body blending with outwardly canted vertical tails, either mounted at the wing tip or at the rear of the fuselage.

The MoD will also contribute funds towards an Anglo-French technology-demonstrator programme to be led by BAe and Dassault. The French air force also has a need for a long-range strike aircraft to replace the Dassault Mirage 2000D/N, although the early emergence of a requirement remains politically sensitive.

With the Dassault Rafale fighter a heavy drain on the French air force's funds, that service is not yet ready to raise in public the need for a dedicated long-range strike-aircraft programme.

The UK and France have already begun the Advanced Military Engine Technology (AMET) programme. This is a joint Rolls-Royce/Snecma project which draws on previous national development projects covered by the Advanced Core Military Engine (ACME) programme.

Elements of the ACME programme were intended to look at producing low-weight, high-pressure fans; improving low-pressure turbines; and examining ceramic matrix composite exhaust diffusers. A variable-cycle high-pressure-ratio compressor is also part of the ACME effort. This programme is known as the Near Term ACME Technology programme.

The UK was also pursuing ACME II(L) aimed at producing a low-pressure system demonstration engine with a vectoring nozzle, and the ACME II (T) and ACME II(C) projects. The latter two cover high-pressure core components and a spool demonstrator, and now form AMET Phase 1. The results of ACME and AMET will feed into an engine demonstrator for the FOA, which will be known as the XG1100.

While the emphasis on the FOA will not be to produce an aircraft with fighter agility, thrust-vectoring is likely to be used to provide a reduced take-off roll and optimise cruise configuration.

Political issues as well as technical concerns will influence the development of the RAF's Tornado replacement plans.

Whitehall sources say that an RAF Air Staff paper produced earlier this year recommended that the UK look to the USA for its next-generation strike aircraft. This basically revisited the RAF's position on the US Navy's General Dynamics/McDonnell Douglas A-12 Avenger II. Before that programme was cancelled, the RAF viewed the A-12 as the "natural successor" to the Tornado GR4.

The sources add, however, that when this paper was circulated within the UK's MoD's Procurement Executive, the serious industrial implications of such a procurement policy were all-too apparent. These issues are now under consideration at the Chief of Defence Procurement level.

With the demise of the A-12 programme, the US project on offer to meet ST(A)425 is the Joint Advanced Strike Technology programme intended to produce the Joint Strike Fighter.

The aircraft is projected to have a single engine, and is intended to replace aircraft such as the Lockheed Martin F-16 and the McDonnell Douglas Harrier II Plus.

Some senior officers in the RAF feel that a single-engined aircraft is unacceptable as an FOA. They also doubt whether the aircraft will meet the RAF's range/payload requirement for the role.

With this partly in mind, the MoD and BAe are continuing to fund and develop the capability to produce a third-generation balanced-stealth design independent of a US aircraft programme.

There is no question that the UK could, on its own, support the development and procurement of a stealth strike aircraft: the problem is that the production run for the RAF alone could not justify such an expensive project.

A joint programme with France, and possibly with Germany as a junior partner, is more attractive in terms of a realistic production run, political complications aside.

Source: Flight International