After recent flights showing off new fuselage-mounted sensor housings, Leonardo has announced that the first modification and flight testing phase for the GCAP testbed aircraft, named Excalibur, is now complete.
The Boeing 757 ‘Excalibur’ testbed, converted from passenger use, will be used to develop technologies for the UK Future Combat Air System (FCAS) program, of which the Global Combat Air Programme (GCAP) fighter is a major part. Flight testing has successfully certified the new fuselage mounted pods, visible on the belly and side of the aircraft, as fit for flight, and they can now be used to house sensors, electronic warfare technology, and communications hardware for development purposes.
For the bumps, the airframe now has the two side and one underbelly blisters, as well as a pitot at the top of the fin under Phase 1 Installation. With these verified in flight tests, Phase 2 will see radar and chin fairings, and a larger aft underbelly blister, and wingpods. https://t.co/mP3dIrj2qR pic.twitter.com/76dgpHS055
— Gareth Jennings (@GarethJennings3) December 9, 2024
Subsequent phases of modifications will see Excalibur equipped with a mock-up nose cone designed to simulate the proposed design of the GCAP fighter, allowing the jet to facilitate radar trials for the upcoming aircraft. This will resemble other similar testbed aircraft like the similarly Boeing 757 based ‘Catfish’. Additional fairings could be fitted to the ‘cheeks’ of the aircraft, either side of the cockpit, and pods attached to the wings.
Excalibur
Owned and operated by UK based aviation services provider 2Excel, the airframe is based at the UK’s famous Boscombe Down facility, home to various military aviation trials units as well as the Empire Test Pilots’ School (ETPS). Before acquiring its new role and registration, the airframe was owned by charter airline Titan Airways as G-POWH. G-POWH spent several periods under lease to Jet2, and also operated some of Titan Airways’ in-house football team charters. Prior to this the airframe had a storied history, serving with Atlasjet, Ethiopian Airlines, Eritrean Airlines, Iberia, and Saudi Arabian Airlines. It arrived at Boscombe Down in 2023.
MOD Boscombe Down recently welcomed the Excalibur Flight Test Aircraft (FTA), which is being transformed into a ‘flying electronics laboratory’ to develop future combat air technology.
The programme represents an exciting collaboration with MOD, Leonardo and 2Excel. #CombatAir pic.twitter.com/QpvW1g5n9E
— QinetiQ Group (@QinetiQ) October 19, 2023
A second Boeing 757, G-BYAW, was acquired by 2Excel and completely disassembled so a hyper-accurate digital twin could be constructed with the same mass and structure as the real thing.
Excalibur is currently a UK owned and operated capability, but the work contributed towards GCAP will equally be of assistance to the other partners in the program. In the longer term, the aircraft will likely become a collaborative project as GCAP progresses further and inches closer to its final design.
The GCAP fighter, a merger of the British-Italian Tempest and Japanese F-X programs, is projected to enter service in the mid 2030s. A demonstrator aircraft will, under the current schedule, take to the air towards the end of this decade. As a sixth-generation fighter, the GCAP platform will incorporate advanced networking allowing seamless cooperation with unmanned ‘loyal wingman’ UCAVs and other manned systems, as well as advanced integrated sensors, adaptable weapon control systems, and open architecture based software allowing for simpler upgrade processes.
From the garden 1550. Boeing 757-200 G-FTAI returning to Boscombe Down.@c_mperman @XH487 @WooksAmesbury @stealthy360 @clark_aviation @julieinthesky @AvHistorian @mariaribera pic.twitter.com/kYq78vtgTw
— Dr Ron (@GbhvfRon) December 3, 2024
Aviation enthusiasts were eager to spot the Excalibur 757 as it made recent test flights with the new housings. The most extensive flight was on Dec. 3, 2024, travelling as far southwest as Cornwall and operating in an interesting pattern off the coast of Portland, Dorset.
A Strong Pedigree
Excalibur is far from the UK’s first foray into the realm of testbed aircraft for future fighter platforms. While many have not attracted the same attention as the Catfish or the Lockheed Martin CATbird have in the United States, they have been equally as important to the development of many aircraft systems.
ZE433, a BAC 1-11, flew as a radar and avionics testbed platform from Boscombe Down from the 1980s until the late 2000s. First being used to trial the Blue Vixen radar that would equip the Sea Harrier FA2, the aircraft was later fitted with the CAPTOR radar destined for the Eurofighter Typhoon.
The 1-11 saw heavy use in the UK for aircraft development purposes, with no fewer than five of the airframes having been listed on the UK military aircraft register. XX105 tested early autoland and digital cockpit technology, while XX919 was used to develop satellite communications capabilities. ZE433’s ‘sister’, ZE432, served with ETPS, while ZH763 became a flying laboratory for a variety of experiments. One notable test saw the aircraft remote controlled in the air from an accompanying Tornado, a test that shows clear lineage to present day trials of UCAVs and loyal wingmen.
Alongside ZE433, the Royal Navy additionally flew a modified HS125 business jet with a Blue Vixen radar nose for a certain time. This aircraft also had the capability to carry instrumentation devices on wing mounted hardpoints.
Most recently, in 2023 the UK defence research company Qinetiq demonstrated a radar and sensor testbed capability on G-ETPL, an Avro RJ100 quadjet, featuring the distinctive fighter-style radome on the nose. The radome appears to resemble that of a Typhoon, and will likely be involved in developing technologies for that platform, while Excalibur focuses on GCAP.
Historically, the nose cone treatment has even been applied to British military helicopters. Royal Navy Sea Kings were used to test the Westland Lynx’s SeaSpray radar, as well as the AgustaWestland Merlin’s Blue Kestrel radar.
While much of the testing previously accomplished with these makeshift adaptations can now be completed virtually, without modifying an existing aircraft, fortunately for those of us who follow them with interest it appears that testbed aircraft will still have a long future to come.
