Although BAE Systems did not make much of a song and dance about it, a scale model of the new Combat Air Flying Demonstrator was on display in the company’s Hall Five at Farnborough this year, allowing an unprecedented opportunity to view the design and configuration in detail.
Before the Farnborough International Airshow in July 2026 little was known about the appearance and configuration of the BAE Systems Combat Air Flying Demonstrator (CAFD): a precursor to the tri-national Global Combat Air Programme (GCAP). Photos had been released showing the forward fuselage in build, of the serpentine engine intake ducts, and of the ejection seat test sled, with just two carefully chosen CGIs released. These gave relatively little away.
What seemed to be new concept configurations for the GCAP Tempest sixth-generation fighter have been revealed over time as though they represented some kind of chronological evolution, but this was not necessarily the case. Large numbers of concepts were tested and evaluated simultaneously, reflecting different priorities and an emphasis on different aspects of the underlying requirement. It is probably the case that the original ‘Pregnant Pelican’ concept, unveiled in mock-up form in 2018, was a relatively early design, but it cannot be assumed that the Concept Class Five model shown at Farnborough in 2022 was newer than the P.189-17B seen at RAF Fairford during the Royal International Air Tattoo in 2024, nor that the current ‘Big Delta’ concept was derived from that Lambda-winged design.
All of the Tempest concepts shown since 2018 have had some features in common. All have had twin tailfins, have lacked horizontal stabilisers and have been large, twin-engined platforms with internal payload bays. Interestingly a ‘concept spread’ shown to selected journalists before the Tempest ‘reveal’ in 2018 showed a rather more diverse range of aircraft configurations and sizes.
The CAFD will not be representative of the production Tempest in configuration and the aircraft is in no sense a Tempest prototype. This is, in part, because the Tempest design still has not been finalised and the final production configuration will not be set in stone until after the demonstrator aircraft flies. Physical manufacturing and assembly of major structural parts for the CAFD got underway at BAE Systems’ facility at Samlesbury in Lancashire in mid-2024. Currently over 11,500 parts have been designed and released into the manufacturing process, representing around 90% of the weight of this aircraft.
The CAFD is large, powered by twin Eurojet EJ200 engines that are fed by serpentine ducts estimated as being 10 m long, and with capacious internal bays to allow generous internal weapons carriage – although the BAE Systems model maker omitted any details of bay locations and shapes. He (or she) did include two unidentified rectangular protrusions on the underside of the rear fuselage. These could be some kind of auxiliary cooling inlets for the engines, or fairings for the test cameras that will be required for filming stores releases from the internal weapons bays.
The CAFD has canted twin tailfins, although these are four-sided ‘swept rectangles’, with parallel leading and trailing edges, rather than the more complex F-22-shaped five-sided pentagonal fins seen on Tempest concepts. They are also more closely spaced and less sharply canted than on those Tempest configurations.
The demonstrator has a cropped, mid-set Delta wing, set well aft, with a notably broad chord at the tips and prominent leading edge root extensions (LERXes). Unusually, prominent fairings are visible on the underside for the control surfaces. These would normally be buried within the wing on an LO platform. Most Tempest configurations have a high wing, with greater span and a variety of planforms.
The CAFD uses diverterless supersonic inlets (DSIs) with a forward-swept cowl and a ‘bump’ on the fuselage. These features combine to push sluggish, turbulent, boundary layer airflow away from the intake lip so that it does not enter the engine, helping to regulate and compress supersonic airflow, slowing it to more stable subsonic speed before reaching the engine compressor – and doing so without heavy, complex splitter plates and variable intake ramps used in older supersonic aircraft. The intake’s contours help to prevent direct radar reflections off internal engine surfaces, thereby reducing the aircraft’s radar cross-section (RCS).
The Lockheed Martin F-35 Lightning II uses a similar intake/DSI configuration, whereas the Lockheed Martin F-22 uses a rearward swept caret intake more like that on Concept Five.
The demonstrator is not fully representative of the eventual GCAP/Tempest in terms of low observable (LO) or stealth performance because that’s not its job; it will be representative of an LO configuration because a representative FCS is required and exploring handling qualities of an LO type configuration etc will be part of its task. It will also have the kind of internal weapon bays that are associated with LO aircraft and these will be cleared for the supersonic release of various weapon types.
Adding stealth coatings etc to make the demonstrator fully low observable would add unnecessarily to the security burden. It would also add massively to the project cost and would duplicate what static RCS pole models will achieve.
NB: A torn Achilles tendon prevented me from attending Farnborough this year, so I’m grateful to friends Glenn Sands, Dave Willis, Khalem Chapman, Mark Ayton and Charlotte Bailey for very kindly taking literally hundreds of photos for me and for stretching the patience of BAE System’s security staff!
