The Combat Air Flying Demonstrator: Rehearsing and preparing for GCAP

BAE Systems has announced that its pioneering Combat Air Flying Demonstrator has reached a major milestone, with two thirds of the aircraft’s structural weight now ‘in manufacturing’. The company also issued the accompanying CGI render of the aircraft.

The UK-funded and developed Combat Air Flying Demonstrator is designed to test, develop and mature a range of new technologies in support of the trinational Global Combat Air Programme (GCAP) with the UK, Italy and Japan. It will allow GCAP partners to better understand risks much earlier than has been possible in any other programme. This important work collectively aims to dramatically reduce the time and costs involved in producing manned combat air programmes, while maintaining the sovereign design, engineering and manufacturing capabilities that are needed to keep the UK at the forefront of global aerospace innovation.

A once-in-a-generation effort

Tony Godbold, Future Combat Air Systems Delivery Director, for BAE Systems, said: “This significant and challenging project will deliver the UK’s first crewed combat demonstrator aircraft in four decades. The programme is accelerating the development of advanced design approaches and manufacturing techniques, helping to sharpen the UK’s industrial edge and deliver benefits beyond the production of the aircraft. As well as developing a unique aircraft, we’re building the technical foundations, workforce readiness and digital maturity essential to deliver the next generation of combat air capability.”

The demonstrator aircraft has design features “that really define what a sixth-generation platform needs to be,” according to a BAE Systems representative, but it is not in any sense a prototype for GCAP. The demonstrator may not even resemble the definitive production GCAP fighter, whose final configuration has not been decided. Rather, it is primarily intended to help BAE Systems to de-risk the forthcoming next-generation combat aircraft programme by rehearsing the application of advanced new-design solutions and digital manufacturing technologies. According to Godbold: “It’s also about re-brigading ourselves and the wider UK industry about what it means to design and manufacture an aircraft from first principles again… it’s been four decades since we’ve done something like this and been at this phase of the programme.”

Air Commodore Johnny Moreton, a former UK Programme Director for the UK Future Combat Air Programme said that: “So one of the life lessons here for a demonstrator programme is: ‘do we have the suitably qualified experienced people that can actually build an aircraft from scratch, go and certify an aircraft, and go and fly the first one?’ Because that’s not something that the UK has done for a while. And actually, that’s a skillset that’s really quite important. How do we get to that world? It would be useful to have some form of design/methodology in sight that says: ‘actually I can learn for the future’. So, the demonstrator is very much a ‘let’s get UK industry and the partners match fit for the future and exploit it downstream as well.’”

 

Innovative design, engineering and manufacturing technologies used by the team will include model-based systems engineering and virtual simulation, 3D printing and additive manufacturing, cobotics (collaborative robotics), and digital twins. This will provide engineers from BAE Systems and the wider supply chain with invaluable experience, ensuring that they are at the forefront of the ongoing revolution in aircraft design and manufacture.

The existence of this ‘once-in-a-generation’ demonstrator programme was officially announced on the opening day of the Farnborough Airshow on 18 July 2022, some five months before the GCAP launch. More than one year before (on 20 May 2021), it had been reported that BAE Systems was using large-scale 3D printing to produce high-temperature mould tooling utilising Airtech Dahltram I-350CF resin (a high temperature-capable, carbon fibre reinforced, Polyetherimide (PEI)-based 3D print resin) for the production of a future combat air demonstrator. Around the time of the demonstrator programme announcement, then UK Defence Secretary Ben Wallace confirmed plans for a low-observable (LO) demonstrator aircraft, jointly funded by the MoD and industry, while UK MoD Director of Future Combat Air, Richard Berthon, said this would fly within the next five years (so, by July 2027) and would play a key role in proving the technology and design principles behind the Tempest Future Combat Air System (FCAS). The aircraft was described as being the first flying combat air demonstrator in a generation.

Testing the engine

In June 2023, BAE Systems revealed that testing of the aircraft’s escape system and of its engine and intake duct had already been completed. Three intake ducts were built at Samlesbury – two for the demonstrator aircraft (by now being referred to as the Flying Technology Demonstrator), and one for the test programme preceding it. The test duct could be fitted with alternative intakes to simulate different operating conditions. A bellmouth intake was used to simulate cruising flight, with an intake representative of the actual aircraft design being used to simulate a ‘pre take-off, brakes on, full throttle’ condition, with air being sucked in from all directions, past the intake lip, and causing lots of intake turbulence.

Engineers used advanced new manufacturing processes to produce the engine duct. This is shaped to slow the air from supersonic to subsonic speeds at the engine face without the need for variable ramps. The intake has fewer moving parts than a traditional fighter intake design, and incorporates diverterless supersonic inlet (DSI) ‘bumps’ to hide the engine from enemy radar, enhancing the aircraft’s LO characteristics.

 

The full-scale duct was fitted to an unmodified Eurojet EJ200 turbofan – sourced from a Royal Air Force (RAF) Eurofighter Typhoon, and testing was undertaken at Rolls-Royce’s site in Filton, Bristol, from early November 2022 to mid-February 2023. The tests used the TP-14 test cell in which the Concorde’s Olympus engine was tested in the 1960s. Testing was undertaken at a wide range of power settings, including reheat, with throttle slams and re-slams conducted. The engine performed as expected, without experiencing air distortion or resonance issues, and there is complete confidence that the engine/intake/duct will perform as advertised throughout the whole envelope.

The aim is to “provide the engine with the ‘quality’ of air that makes the EJ200 think that it’s sitting in a Typhoon,” said Conrad Banks, Chief Engineer, Rolls-Royce Defence Future Programmes, as this will enable the powerplant to be operated in the demonstrator using existing flight clearances.

Testing crew subsystems

The crew escape system for the demonstrator will be based on an unmodified Martin Baker Mk16A ejection seat (as used in the Typhoon), and aircrew will wear Typhoon flying gear, including the AEA and Mk 10 helmet, which were also used by the test mannequins.

A series of ejection seat trials were undertaken, using an aerodynamically representative forward fuselage section mounted on a rocket-propelled sled. The crew escape system test campaign started on 16 December 2021 with a static firing at Martin Baker’s factory airfield at Chalgrove, proving the canopy design – which was a cast acrylic design incorporating MDC technology from the BAE Hawk advanced jet trainer. This static firing was followed by a series of four sled test seat qualification firings at Langford Lodge in Northern Ireland between 31 March 2022 and the end of June that year. Firings were made at two speeds – 519 km/h (280 kn) and 833 km/h (450 kn), using a Class 1 mannequin (representing a lightweight female pilot in summer flying gear), and a Class 6 mannequin (representing a heavy male pilot in winter kit).

 

The demonstrator facility at Warton includes a so-called hybrid rig, with four linked development rigs, employing a mix of hardware, emulators and digital models. One of these is for the cockpit, one for the flight control system, one for computing and models, and another for the utility management system. It was designed to provide the crucial evidence that will support real world live flight trials.

The cockpit rig incorporates a touchscreen large area display (LAD) but lacks the smaller high-integrity panels (HIPs), which now seem to be a feature of the similar LAD being developed for the Typhoon. Because of the size of the LAD, the aircraft will use a sidestick rather than a central control column, and may incorporate haptic feedback. The cockpit rig is being used to develop, test and evaluate flying controls, flight control laws and displays. It will eventually be used for pilot training prior to first flight.

The hybrid rig is connected to a triplex fly-by-wire flight control system, with a set of actual hydraulic actuators for the three flaperons on one wing, and one for one of the ruddervators, with the controls on the other side of the aircraft being digital models.

 

The company said in 2023 that some ten pilots had amassed 170 flying hours, in 125 sorties, in the digital environment. Four of the pilots were Warton-based BAE Systems test pilots (Steve Formoso, Andrew Mallery-Blyth, Luke Gili-Ross and Glyn Gogerty), with a team of six pilots from the RAF’s Rapid Capabilities Office (RCO) and the RAF’s No.41 Test and Evaluation Squadron, led by Group Captain Willie Hackett. By July 2024, when BAE Systems announced that the demonstrator had passed its critical design review (CDR, in May 2024), the ‘flying time’ had increased to “more than 215 hours”.

Manufacturing and assembly

The CDR would normally be the point at which a traditional combat aircraft programme would enter into the manufacturing phase. Modern digital design and manufacturing processes allowed BAE Systems to undertake production in parallel with the review activity.

BAE Systems said that more than half of the weight of the aircraft had been released into the manufacturing process, and that all of the major units were in build, including the front, centre, and rear fuselage, and the wings, with assembly of all having started in 2023. The centre fuselage was one of the earliest units into build. A centre fuselage is typically the long-lead time item, taking longest to assemble and involving a huge amount of complex design and manufacturing operations.

While assembly was underway by BAE Systems at Warton, Paul Wilde, the then Head of Tempest at BAE Systems, said that the “vast majority” of the demonstrator was being manufactured outside Warton, in the wider supply chain across the UK. Wilde also noted that the demonstrator project was taking advantage of the latest manufacturing processes, including the use of hot isostatic pressing (HIP) technology. This takes Titanium powder and fuses it together using extreme heat and pressure to create complex shape parts that could not otherwise be manufactured as a single piece. In addition, traditional casting methods might require a four-year lead time, while HIP might take just six months.

 

As well as developing the skills, tools, processes and techniques that will be needed to develop the definitive GCAP Tempest aircraft, Wilde said that the demonstrator would be used to test, evaluate and demonstrate key elements of the next generation combat air design, pushing technology boundaries. The aircraft will incorporate a combination of supersonic and LO features.

The aircraft will incorporate some stealth compatible features and low observability shaping techniques, similar to those that are likely to be employed on the Tempest platform, thereby exercising BAE Systems’ LO design capabilities. Some of these stem from the company’s learning on the Taranis unmanned combat aerial vehicle (UCAV), which was regarded as having been “cutting edge on a global scale” according to a company representative. BAE Systems says that it has been testing a lot of shape and mould line styles that will help to inform LO design features for GCAP concepting.

The demonstrator aircraft will embody LO design features and principles, and LO aspects have been incorporated through the design and manufacturing process. It will not itself be ‘stealthy’, however. The canopy, for example, will be of conventional construction, and will incorporate miniature detonating cord (MDC), while stealth coatings are unlikely to be applied. Significantly, it was revealed for the first time that an integrated payload bay would be included. Test and evaluation of the integrated bay was expected to form an important part of learning for the GCAP programme.

What we know so far

On 16 July 2025, BAE Systems announced that it was revealing “the design of the UK’s flagship Combat Air Flying Demonstrator”, as the aircraft reached a major milestone, with two thirds of its structural weight by then in manufacturing. In fact, the CGI render of the aircraft was deliberately unrevealing, and the company was careful to give little away in briefings and in answering questions from journalists.

Unsurprisingly, the demonstrator aircraft is a large, twin-finned, twin-engined design, without horizontal tails. Superficially, the aircraft resembles a tailless F-35 or Kaan, with forward-swept intakes (without obvious DSI ‘bumps’ though these are believed to be a feature of the aircraft). The demonstrator has a ‘boxed in’ rear fuselage section, giving a broad, flat upper fuselage, like that of the original Tempest model revealed in 2018. The front three-quarters view showed a slightly cranked inboard leading edge – perhaps a simple leading-edge root extension (LERX) – which would seem to be sub-optimal from an LO point of view, but BAE Systems declined to explain the reason for this.

 

The remainder of the wing planform was not apparent from the CGI, but BAE described it as having a “cropped delta” configuration, unlike the Lambda wing of the original ‘Pregnant Pelican’ Tempest concept and several subsequent designs, and quite unlike the unusual planform of the ‘Concept Class 5’ study. It may be that this ‘simpler’ shape was chosen for cost/structural complexity reasons, but BAE Systems refused to confirm this speculation. BAE also declined to say whether the trailing edge was swept back, swept forward, or straight, and did not answer whether the wingtips were parallel to the aircraft centreline or slightly ‘clipped’.

The company acknowledges that the demonstrator aircraft is large, and says that it has to be, “in order to demonstrate some of the technologies… some of that requires a material size, a platform to be able to do so, in terms of the relative scale to GCAP.”

The vertical tailfins look rather more conservative than those seen on previous Tempest concepts, being more ‘upright’ (less canted and also less ‘swept’ in side elevation), and more ‘rectangular’ (or trapezoidal) with a more conventional ‘straight’ trailing edge than the ‘five-sided’ fins seen on previous GCAP/Tempest concepts. BAE Systems did not answer questions as to whether this had been chosen for cost/complexity reasons, or for some other reason.

In the CGI image, the aircraft has a single-piece windscreen and canopy, but the aircraft will actually have a separate windscreen and canopy, like the ejection seat test sled. In fact, the whole of the wide, heavily chined forward fuselage is (for obvious reasons) identical to the forward fuselage section used for escape system testing.

BAE Systems says that the demonstrator aircraft’s main structure, wings and tail fins are all now taking shape, using advanced robotics, cobotics and digital manufacturing and assembly technologies. Godbold said that: “We’re pushing the boundaries of not just how we’re designing it, but also how we’re assembling some of these products.”

The company has manufactured what it calls: “The biggest flying Carbon thick skin that we’ve ever made up in the Northwest,” in the shape of the centre fuselage skin. The demonstrator has allowed the company and the supply chain to make good, complex shapes in Carbon for the first time of asking – quite an achievement given that it can be particularly tricky to predict how Carbon ‘springs’, and a testament to the modelling capabilities now available.

The final set of Carbon wing skins for the aircraft were delivered to the company’s Warton site on 14 July, having been manufactured by an unnamed company within the supply chain – described coyly as a high-value manufacturing catapult. The wing skins were, Godbold said, “made using a different set of technology than we’re used to.” Though BAE Systems refrained from saying so, using very large single-piece skins is advantageous from an LO point of view.

According to a BAE Systems representative, various parts will be sourced from “a number of different aircraft that the UK operates”, though there has been nothing as major as was incorporated on the EAP, which used an entire Tornado back end, including the tailfin. Two EJ200 engines donated by the UK MoD will be installed in the aircraft, and the landing gear will be modified from a Tornado undercarriage.

 

‘North of 13’ Test pilots from BAE Systems, Rolls-Royce and the RAF have now flown more than 300 hours of the Combat Air Flying Demonstrator in the bespoke hybrid rig. Using these simulated flight trials, pilots and engineers can rapidly assess the flight control systems during more complex flight manoeuvres, capturing crucial data about how the jet will handle and perform, years before the aircraft makes its first flight.

BAE Systems says that the first flight window remains as per the July 2022 announcement, commenting that the Flying Combat Air Demonstrator will be ready for first flight by the end of 2027 – the exact date will be finalised nearer the time to optimise learning and maximum benefit to GCAP.

The aircraft is currently set to fly within three years, but company spokespersons say that there is “nuance between when the aircraft will be ready to fly versus when the programme will determine the best date to fly.” To avoid any confusion or suggestion that the programme has been delayed, BAE Systems stressed that it will be ready for a first flight by the end of 2027, but that the exact date will be finalised/selected nearer the time based on a number of facts around the core GCAP programme, regulator, and various others. An uncharitable observer would note that the company is now talking about the end of 2027, rather than the end of July 2027, which would mark the end of the originally announced ‘within five years’ timescale.

The Combat Air Flying Demonstrator still lacks a name, and its Warton Project number remains unknown (it may be close to the P189 designation applied to some Tempest concepts). If the wind-themed Tornado/Typhoon/Tempest naming convention is to be followed, an obvious choice might be Hurricane. The six journalists briefed on the Combat Air Flying Demonstrator on 14 July were urged to submit suggestions to a certain someone at BAE Systems.

Jon Lake

Author: Passionate about aviation and flying, Jon Lake grew up around aeroplanes, learned to glide before he could drive, learned to fly with the University of London Air Squadron, and has been in aviation publishing since 1984.