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