The Tempest combat aircraft: there's a storm coming

13 min read

Stuart Nathan tries to unravel some of the engineering aspects of Tempest, the UK’s new combat aircraft, whose development was announced this summer

When BAE Systems and secretary of state for defence Gavin Williamson teamed up in July at the Farnborough Airshow to announce that a new combat aircraft would be developed for the UK, it came as something of a surprise. The RAF’s main fighter aircraft, the Typhoon, still has the gloss of a relative newcomer. Tornado, its “older brother”, is still in service, and the F-35 Lightning II has not yet become active. Surely it was too early to start developing yet another fighter aircraft?

Moreover, the way the announcement was made led to much of the mainstream coverage (including The Engineer's; see above link) concluding that the new aircraft, which is to be named Tempest, was to be a purely UK venture. This also came as a surprise. The last combat aircraft in service with the RAF and Fleet Air Arm that was not an international collaboration was the Harrier, which made its debut in 1969.

Tempest combat aircraft
Tempest will carry swarming drones in its payload bay which its pilot will co-ordinate during missions

Since then, the Jaguar was an Anglo-French production; Tornado involved the UK, France, Italy and West Germany; Typhoon these four partners plus Spain, and the development programme for Lightning II involves the US, Australia, Canada, Norway, Denmark, Netherlands and Turkey, alongside the UK.

The official line throughout these programmes has been that cutting-edge combat aircraft require such a complex set of technologies that no single country is capable of producing them, certainly not with limited budgets of European nations. So what has changed?

As ever, the true picture has been somewhat obscured by politics. For although the development of a combat aircraft would undoubtedly be the largest and most complex and highest-technology single engineering project starting in the UK for many years – probably since the project to develop the Queen Elizabeth-class aircraft carriers – no defence-related technology programme can possibly be free of politics.

Arguably, the most important single factor behind the announcement and its timing is Britain’s impending exit from the European Union. The government is very keen – if not desperate – to maintain the UK’s image as a leading nation internationally, and defence is undeniably a tool to do this. Anxious that cutting ties with its closest international partners does not leave the country looking like a minor player, what better way than to flex its muscle? In the RAF’s centenary year, demonstrating that we can still develop combat aircraft – the primary way that nations project force in warfare - is ideal.

The Farnborough reveal was not as simple as it seemed. Williamson and BAE Systems in fact made three announcements that were conflated into one by most of the coverage at the time. These were interlinked, so reporting the existence of ‘Project Tempest’ was the simplest way to report the story.

“The announcement came out like three legs of a stool,” Andrew Kennedy, head of strategy for military air and information at BAE Systems, explained to The Engineer. “At the same time as the government made the announcement of the funding into ‘Team Tempest’, they then announced the establishment of a team to look at the combat air acquisition programme, which is effectively starting the process for the acquisition of a new aircraft.

The third element was the combat air strategy which effectively provides a framework for the government in which future decisions are going to be made. So all three of them are closely linked, but they are actually separate. It’s a bit confusing.”

The assumption that Tempest is going to be an all-British production is mistaken, Kennedy insists. Williamson’s announcement sounded the starting gun for a series of year-long feasibility studies with potential partners to see whether requirements for a future combat aircraft could be aligned, along with investment plans and the industrial requirements to develop and build technologies that would be part of such a project.

This inevitably obscures any discussion of what technologies might find their way on to Tempest and BAE Systems is unwilling to dictate what technological solutions might be part of the future system. “We don’t want to say ‘this is the solution’ and then try to force other people to come along with that,” Kennedy said. “The whole point of these feasibility studies was to try to align requirements rather than to force our solutions on to other people, so it’s a true partnership.” At this point in the project, potential partners have not yet been revealed, if they have even been identified.

The RAF and Ministry of Defence are unwilling to discuss an aircraft that does not exist yet, so to gain some insight into the role a future combat aircraft might play, The Engineer consulted Greg Bagwell, president of the Air Power Association, an organisation that brings together individuals, companies and bodies with an experience and interest in aerial combat. Bagwell, a former Air Marshal in the RAF, is well placed to provide such a view. As well as being air commander for RAF operations over Libya in 2009, earlier in his career he served as a Tornado pilot; he has also flown F-16 Fighting Falcons and Typhoons. His comments as reported here are his personal views, based on that considerable experience.

Harrier is a useful example to look at to see how the UK’s approach to combat aircraft changed in the intervening half-century, Bagwell said. “By the time we had finished with Harrier, it looked a lot like an AV-8B which, of course, was very much a US product. In many ways the way the Harrier morphed from a UK to a US product is synonymous with the way the UK defence aerospace landscape has shifted.”

He explained: “To be brutally honest, the UK home market is not big enough to be able to justify a completely new aeroplane, the numbers would not add up. So it has to be done with export in mind which almost undoubtedly means partnerships; and clearly there is competition.”

That competition would include the US, which is hoping to sell the F-35 into additional markets; and France and Germany, which are also reported to be in discussions about developing a new combat aircraft. In fact, Bagwell said, countries including India, Korea and Turkey are all technologically “in the foothills” of generating new combat aircraft. These are all countries to which the UK might be hoping to sell Tempest, along with its existing export base which includes Qatar, Saudi Arabia and Australia, so these are countries which are probably among the potential partners with which Williamson, the Ministry of Defence and BAE Systems hope to be commencing discussions.

So what will they be discussing? Tempest will be a sixth-generation fighter – such ‘generations’ being a somewhat slippery classification applied to aircraft of the jet era. These aircraft are inevitably designed to fill multiple roles. Typhoon, for example, is primarily an air superiority aircraft, designed to engage in air-to-air combat and intercept other aircraft to ensure that its operator has the freedom to fly over disputed areas. The F-35, meanwhile, is optimised for ground attack. Despite this optimisation, however, both aircraft are capable of the other role as designed, and in any case over their service lifetimes aircraft are inevitably adapted for new jobs.

“Look at Tornado, for example,” Bagwell said. “We designed that to fly low-level missions over Germany in a full-on war with the Warsaw Pact. Whoever would have thought it would be flying counterinsurgency missions over urban areas in Afghanistan and Syria? But we adapted it through the use of different sensors and weapon systems.”

tempest combat aircraft
Some of the features in future virtual cockpit set-ups in both Typhoon and Tempest

In a recent briefing at BAE Systems air combat development site at Warton in Lancashire, journalists were told that some air forces are becoming reluctant to use aircraft for too many different roles, because of concerns that if enemies developed a method for bringing down one aircraft, it could potentially seriously damage the capability to fly many different types of mission.

Bagwell agrees that the prospect of an air force flying only one type of aircraft for everything is ridiculous, but the cost benefits of a modular approach with flexible aircraft are undeniable. “Anybody who thinks we can afford one-trick ponies is on the wrong track,” he said. “Look at the F-22 Raptor, for example. It’s very good at its one role – air superiority – but when you haven’t been able to use it for 10 years, people started to doubt its value for money, which is why it got cancelled.”

The combat air strategy document itself is quite vague: in summary, it states that the UK will retain the capability to carry out air-to-air and air-to-surface combat with the ability to carry out surveillance, reconnaissance, electronic warfare and command and control tasks concurrently. Details are thin, in line with Kennedy’s comments about the evolving nature of the programme and desire to consult with partners and allies. However, it is made clear that the strategy rests upon F-35 and Typhoon for the near future, and commits the UK to continue to invest and upgrade Typhoon. This is an important point, Kennedy stresses, and represents a change in the way the UK has previously approached new aircraft development.

At Farnborough, Williamson announced that £2bn would be invested in the development of Tempest up to 2020, and BAE Systems would lead development with Rolls-Royce contributing engines, MBDA integrating weapons and Italian company Leonardo developing sensors and avionics.

The plan is to finalise design in the early 2020s, produce a flyable prototype by 2025 and have the aircraft entering service by about 2035. By that time, Typhoons are likely to have many flying hours still in reserve – the aircraft is still in production – and those in service will be phased out gradually over five to 10 years, in line with the RAF’s existing practices.

In the meantime, many of the systems which will be developed for Tempest are likely to be first in service on upgraded Typhoons. “We’re trying to make sure we can maximise the return on investment on Typhoon by rolling over those capabilities on to Tempest,” Kennedy said.

“We could see it almost as just changing the skin on a current-generation system and then you gradually upgrade it as you go through, so it’s an evolution rather than everything stops and we start again with the future combat air system.”

This, he explained, is in part a reaction to a previous complaint that the RAF and other customers had about the evolution of aircraft and the way they are superseded. “We are requiring Tornado at the peak of its capability now, but we are also retiring it because the airframe really doesn’t have any life in it any more. The change now is that we are seeing airframe as a system in the same way as we see radar, for example, as a system: it’s something that can be upgraded.”

This is a common approach in many other heavy industries such as automotive and civil aerospace, where features are introduced as “top-of-the-line” in existing models and then rolled on to their successors. “We have looked around and taken best practice from these other sectors,” Kennedy said.

The hoped-for effect, he added, is that Tempest will be fully effective from the moment it enters service, as most of its key systems will already be tried and tested. The timescale for developing Tempest seems ambitious to Bagwell, but Kennedy stated that it was market-driven. “The mid-2030s is when we see the demand for this sort of aircraft beginning.” It is not unusually long or short for this type of project, he claimed.

tempest combat aircraft
The mock-up of Tempest on display at the Farnborough Airshow gave away few engineering details

The aircraft itself – or at least a concept mock-up – graced the BAE Systems stand at Farnborough.  However, details of what the final aircraft will include are, understandably, sparse. Engine partner Rolls-Royce revealed that it is looking towards new, low-weight materials, such as ceramic composites in the turbine, and in one tantalising detail the new aircraft is expected to need so much electrical power that generation capability will be integrated into the engine itself in the form of magnets directly bonded to the turbine shaft.

Among the list of possible features discussed in the initial documents describing plans for Tempest is the aspiration to use directed energy weapons. These are mentioned in the context of “non-kinetic attacks” implying they might be used, for example, to knock out enemy sensor systems rather than to shoot down other aircraft, but in either case a great deal of electrical energy will be needed to operate them.

Bagwell pointed out that a major advantage of directed energy weapons over conventional projectiles is that, as long as energy is available, there is no chance of running out of ammunition. “You are clearly going to need some serious power,” he said. “It might replace a gun, it might replace a close-in missile, but the idea that you are going to use a laser to intercept something at 30, 40, 50 miles away, I think we are some way off yet.” Fantasies of Star Wars-style dogfights are just that, he said. “But whoever designed the Star Wars scenes might turn out to be a visionary in 50 years’ time.”

According to Kennedy, any technologies mentioned at the Team Tempest launch event should be seen as an aspiration, rather than a concrete announcement; partly because everything is still subject to the feasibility studies with potential partners, and partly because in many cases they simply haven’t been developed yet.

One example of this is stealth technologies. The Farnborough mock-up featured the sharp angles along the sides of the fuselage which are also a feature of the F-35 and are characteristic of the current design philosophy for confusing radar systems. However, according to Bagwell, “what is low-observable today almost certainly won’t be low-observable in the future, because radar manufacturers are developing their products as well.” Bagwell described this as a race between airframe makers and radar, but to Kennedy this is just a fact of life in the defence sector. “There’s always a kind of competition, whether it’s in stealth or any other air or military system: offensive and defensive capabilities tend to develop in parallel.”

There are a few other hints that can be gleaned from the mock-up. Firstly, Tempest is, like Typhoon, a twin-engine aircraft (F-35 is single-engine), but likely to be slightly larger than both. This would give it greater flexibility in weapons load and possibly implies longer range. The twin tailplane configuration improves manoeuvrability and suggests a trade-off against stealth.

What’s more, any observer would have noted that in recent years all new combat aircraft have looked very similar. “There are only so many ways you can design an aeroplane in a wind tunnel which has both stealth and basic kinematics built in,” Bagwell said.

Gavin Williamson said that Tempest would be capable of flying as a piloted aircraft or in an autonomous mode. This is in line with discussions over whether future fighter aircraft will be piloted or drones, but to Bagwell this was an example of hedging bets. “Unmanned is clearly growing in utility, and there could be a time downstream where it is technically feasible that all combat will be conducted with unmanned vehicles. However, we haven’t even cracked cars, trucks or ships yet, so why is the most difficult thing in the world (combat aircraft) something we are looking to solve or accept first?”

There are two potential problems with flying an aircraft like Tempest as a drone, he said. “I think there’s a moral argument in there about keeping a human in the decision loop.” The second reason is more practical: “If it’s unmanned, is it controlled through remote means? And if that’s the case, can you guarantee your satellite links?”

For Bagwell, there are advantages and disadvantages to both piloted and pilotless operation, but making an aircraft capable of both is likely to just end up costing more money and leading to compromises that blunt the advantages in both cases.

However, the use of an aircraft to control a swarm of drones in the battle space, which it might carry itself in its payload bay, is another matter and one which is likely to be a reality quite quickly. “The manned/unmanned mix is a thing of the future and if we haven’t got there before Tempest I’ll be amazed,” Bagwell said. “There is effectively no difference between programmable decoys or swarm drones then firing eight missiles at different targets. It’s not a big leap of faith, and they make the ‘quarterback’ aircraft more survivable and more lethal. The bigger issue is making cheap enough swarm drones.”

This, and Bagwell’s use of the term quarterback, implies that even in piloted mode, the actual job of the “pilot” will be less one of actively flying the aircraft, and more one of monitoring the battle space. “Aeroplanes are much easier to fly than they were 20 years ago,” he said. “With flight control software, fly by wire, new sensors, collision warning directors and ground proximity systems, the idea that the pilot dedicates the majority of his or her time to flying the aeroplane is just not true any more. In the past, we had to select Harrier pilots very carefully because it was so difficult to control the hover. That is not the case in the F-35B. But although aeroplanes are much easier to fly, they are much harder to operate. There is lots of data… lots of fusion, lots of things to think about; and you have to do it at greater ranges and higher speeds.”

This is the thinking behind a system which will definitely find its way on to Tempest and will first be used in upgraded Typhoons: virtual cockpit. The idea is that instead of the huge array of dials and switches lining the cockpit, all of the indicators and controls will be projected on the monitor screen inside the pilot’s helmet, as described in The Engineer’s recent feature on the new Striker II helmet. This will even extend to the use of haptic gloves so that when the pilot reaches for a “virtual switch”, which he or she can see but does not actually exist, there will be a feeling of pressing the switch replicated using vibration devices mounted in the fingertip.

One feature of such a system will be that the display will be configurable by the pilot, so they can place the display wherever in their field of vision they feel it is most useful. For mid air-refuelling, for example, they might want to place a fuel tank display over the point in their vision where the refuelling probe docks with the trailing basket from the tanker. Another feature that is being tested is a “smartwatch”-type display that the pilot can pull out from their wrist, which might feature their own biometric data collected by sensors inside their flight suit. It might even display the biometric data of other pilots in their squadron.

“If you’re detecting blood pressure, pulse rate or galvanic skin response, that can give you an indication that somebody is feeling particularly stressed,” explained BAE Systems head of human factors Jean Page. “And if your squadron leader knows that, it will help distribute the workload around the squadron to ensure that everybody is working at the peak of their ability and nobody is overloaded.”

Assessing the cognitive load on a pilot is essential to designing such a system. Page is working with psychologists to determine how much information a pilot can usefully process in the pressured atmosphere of a cockpit in a battle space. Such information will help to determine how virtual cockpit works in Tempest when it is ported over from Typhoon. One factor which the team already knows it will have to accommodate is the physical effect of G-forces. “The eyes are affected during a 9G manoeuvre, so we know, for example, that we wouldn’t be able to reliably use gaze tracking under those circumstances,” Page said. G-forces are already countered by inflatable pressure cuffs in flight suits which help keep blood circulating and prevent blackouts, and this is likely to be developed further.

One system that may be used in this environment is artificial intelligence to determine which information is likely to be most useful to the pilot. Bagwell believes this is more likely than the use of AI to actually fly the aircraft.

“Information flow and fusion is now more automated, and this is where I think artificial intelligence has a place – it’s not to make autonomous decisions to pull the trigger or not, but provide you with fused information so you can decide more easily. It’s more assisted intelligence than artificial intelligence.”

As a self-confessed old-school combat pilot, Bagwell confesses he is sceptical about some aspects of virtual cockpit. “Flying an aeroplane can be quite a tactile thing,” he said. “Replicating the level of feedback you get from actually pressing a physical button or handling the controls, getting that through gloves and without the use of simple sight and feel seems to me to be denying two fundamental senses – I can see the concept but I’m a little sceptical. But the idea of producing more and more information through different means, we are already there. The old analogue systems on aircraft now are the back-up systems, not the primary.”

One thing that Bagwell was particularly keen to stress is that the notions of what is ‘high-tech’ have shifted, and today, military technology is likely to be somewhat more primitive than consumer technology: a complete reversal of the situation when he joined the RAF aged 18. “Today, there is probably more memory in your mobile phone than most combat aircraft flying, and a faster processor: the F-35 certainly doesn’t have that much. Defence technology these days changes quite slowly.  That’s relatively recent, for a number of reasons. One is that digital technologies, processors and software are developing well inside the life cycle of an aircraft platform.  Also, whereas before defence were the innovators because they had the resources to hand fast, now because commercial demand is high and the cost of R&D of some technologies has reduced, it is the commercial marketplace that demands volume and fast turnaround times. You are now seeing a Leviathan defence marketplace where, whether it be through design or test, we can’t build these things very quickly any more.”