U.K. designed, built low-observable platform
to maintain its defense/aerospace player status
DOUGLAS BARRIE/LONDON
Under a highly classified program Britain has built and tested a full-scale low-observable aircraft design as part of a broad-based effort into next-generation air combat platforms.
The program, which had cover names including Replica and Testbed, was jointly funded by the Defense Ministry and BAE Systems. The latter built a full-scale model of the low-observable (LO) design, and tested it on its radar cross-section range at its Warton site, in the northeast of England.
Although the full-scale Replica design never flew, the model was built with features representative of an actual LO aircraft. The then-Defense and Evaluation Research Agency (now Defense Science Technology Laboratory) was also involved in the conceptual study phase.
ONE SOURCE CLOSE to the program told Aviation Week & Space Technology that airframe components were constructed to "pretty tight specifications." The design also included conformal shared-apertures, along with having an internal weapons bay.
Build and test of the Replica airframe was carried out under extremely tight security by BAE's Advanced Technology Demonstration Center. Testing on the radar cross-section range is understood to have been carried out only at night. The superstructure housing the test stand can be moved to allow for radar cross-section trials.
The program, launched in 1994, culminated in what is described by the company as "the most extensive and ambitious radar cross-section measurement program undertaken in the U.K. to date." The RCS trials were completed in 1999: "Testing proved successful, demonstrating that the designed model achieved the signature targets."
Much of the Replica airframe consisted of carbon fiber composite skin panels. The airframe was a wing-body blended design with a V-tail. The canopy was treated to avoid radar scattering from within the cockpit environment. The design also exhibits an unusual curved edge to the radome.
The program was the major element of U.K. work into LO platforms during the 1990s intended to address future requirements, and to ensure the Defense Ministry and industry remained a credible--and informed--partner in potential collaborations. Replica was intended to address both air force and navy needs.
The latter half of the 1990s saw the Defense Ministry and the government attempt to ensure access to national, international and multinational routes with regard to the development of next-generation low-observable combat aircraft.
In parallel to continuing long-standing bilateral agreements with Washington on LO, the government also weighed the option of possible European collaboration. However, the nature of the U.K.-U.S. bilateral restricted London's room to maneuver as far as European collaboration was concerned, so long as it wanted to maintain U.S. access.
While the U.K. eventually joined the European Technology Acquisition Program--intended to address next-generation air platform needs--it has finessed its involvement status to allow it to pick the areas of technology in which it participates. Such an approach was crafted to ensure the protection of the LO relationship with Washington.
More importantly, it also became a launch partner for the Joint Strike Fighter program--with the aircraft viewed as becoming "the U.K.'s primary manned offensive air platform," by senior air force officials. Both the government and industry remain keen to maximize access to the LO aspects of the JSF, with the Replica program as leverage--if needed.
BAE and the Defense Ministry invested jointly more than 20 million pounds ($31 million) in Replica, with the former also pitching in additional research and technology funding on the program.
Alongside Replica and Testbed, a further codeword associated with British stealth research during the early 1990s was HALO. This has been variously ascribed as meaning Hawk Low Observable--a Hawk jet trainer modified by BAE to examine the impact of modest stealth changes to an aircraft--and High Agility Low Observable.
REPLICA--AT LEAST IN PLAN form--shows notable resemblance to the McDonnell Douglas/British Aerospace....
31 Mar 03 AWST