A second phase of modification work to prepare an ex-airline Boeing 757 for use as a flying testbed to support the development and trial of UK combat air technologies is due for completion before year-end.
In the process of being extensively adapted by 2Excel Aviation, the Excalibur flight-test aircraft has now received its remaining additional external structures, with the company awaiting receipt of the twinjet’s distinctive fighter radome.
“The new ‘lumps and bumps’ are either on or coming – the only one that’s not finished is the nose,” says 2Excel director Chris Norton.
Being adapted to support the UK’s Future Combat Air System (FCAS) programme efforts, and specifically radar and communications equipment developed by Leonardo UK, the Excalibur platform – registered G-FTAI – underwent an initial campaign of stability proving flights late last year with an initial package of airframe updates.
Performed from the Ministry of Defence’s Boscombe Down site in Wiltshire, that activity followed 2Excel’s installation of large side-fuselage structures aft of the cockpit – nicknamed ears – along with a belly pod.
“Everything was at the front, so that was the most unstable of the configurations,” Norton says of that campaign, which concluded in late 2024.
“We have now got a lower-belly fairing, wing pods, and the nose cone to come.” Not shown on previous artist’s renderings of the aircraft, the under-wing pods will provide an unobstructed field of view for sensors.
The strengthened and extended nose section has been one of the project’s most challenging aspects, due to the twinjet having to accommodate a heavy fighter radar. This has involved 2Excel’s engineers designing and installing a 0.9m (3ft)-long frame in front of the bulkhead, to which the almost 3m-long fighter radome – which will eventually cover an active electronically scanned array sensor – will be fitted.
“Now we have changed the outer mould line again, so we have to re-test all of those test points, and do that right across the operational envelope,” he says.
That process is expected to require “tens of flying hours” to clear. During its previous campaign, “the [performance] model was very tight, and what we tested was pretty much as we predicted”, he notes.
Meanwhile, work is also advancing to prepare the unique jet’s interior to be able to support a broad range of test activities over the coming years.
“The task operator stations are all built and are sitting ready to go in,” he says, with associated wiring installation work currently taking place.
“Racks containing mission equipment also are waiting addition,” he says. At the rear of the cabin, the company will be equipping a demonstration area and VIP station, “where people can watch what’s going on upfront in flight”.
Norton spoke to FlightGlobal on 11 September at the DSEI show in London, where 2Excel’s exhibit was positioned next to a large stand promoting the Global Combat Air Programme (GCAP) and Edgewing – the industry joint venture tasked with developing a sixth-generation fighter for Italy, Japan and the UK.
While work to prepare the Excalibur platform stems from a UK-only FCAS/Team Tempest effort, it could potentially also be employed in support of the GCAP endeavour, which should deliver an operational capability from 2035.
“The whole purpose [of Excalibur] is it’s an integrated testbed, so if Italy is providing X and Japan is providing Y those things all need to be connected, to show how it all works together,” Norton notes.
Also at the show, Italy’s Leonardo disclosed plans to employ an unspecified Gulfstream type to support its GCAP test activities, while Japan is likely to use an adapted Kawasaki C-2 transport in a similar role.
