They have names such as NGAD (Next Generation Air Dominance, -> Latest findings on the NGAD F-47) from BoeingGCAP (Global Combat Air Program) from BAE Systems, Leonardo and Mitsubishi (-> GCAP project on track), or FCAS (Future Combat Air System) from Airbus and Dassault Aviation. They still only exist as computer graphics – often futuristic, sometimes with the appearance of a manta ray. But what lies behind these elegant shapes? And how do these 6th generation fighter aircraft differ from their predecessors?
The short answer: in many ways. The long answer: many technologies are not completely new, but their interaction and implementation should reach a new level. Proven concepts are being further developed and new approaches integrated – with the aim of securing airspace dominance in an increasingly networked, digital battlefield.
“Stealth” is now called “Low Observable”
What used to be known as “stealth” has long been called “low observable” (LO) by experts. This is not just about stealth technology against radar, but about a comprehensive reduction of all signatures: radar, infrared, acoustics and even visible light.
What is striking is that many new designs dispense with classic, eye-catching control surfaces. Vertical tails are getting smaller – or disappearing completely. Duck wings like those on the Eurofighter, Rafale or Gripen also seem to have had their day. Some concepts even dispense with movable leading edges on the wings.
The outer skin of the jets is smoother and more seamless – a flowing design without unnecessary edges. Underneath: complex cooling systems that dissipate frictional heat, especially at the leading edge of the wing, which is subject to high stress. LO is no longer limited to radar waves: Modern infrared sensors – especially since the 5th generation – detect heat signatures at great distances. The reduction of both radar and heat signatures is therefore equally important today.
Engines: More thrust, more control
If aerodynamic control surfaces are reduced or omitted altogether, control over attitude and heading must come from another source – the keyword is thrust vector control. Instead of using rudders, the jet is steered by deflecting the thrust of the engine – quickly, precisely and with a low signature.
But this comes at a price: during take-off, the engine has to perform better if there are no adjustable surfaces to generate the necessary lift.
Modern air-to-air missiles such as the Meteor, AIM-174B or the new AIM-260 have ever greater ranges. This forces so-called “force multipliers” such as AWACS aircraft or tankers to stay further away from the battle area – the risk of becoming a target themselves is too great.
For 6th generation fighter aircraft, this means more self-sufficiency. They have to carry larger fuel reserves, fly more economically – and all this without additional external tanks, as these are not compatible with stealth. A key technology for this is “supercruise” – supersonic flight without afterburner. But the faster you fly, the hotter the outer skin gets. Where exactly the thermal limit lies remains a well-kept secret.
A key problem here is the heat inside. The F-35 already struggles with heat build-up – ventilation slots for cooling to the outside would be effective, but would compromise the stealth. Cooling must therefore come from the inside. Next-generation engines must not only deliver more thrust, but also provide significantly more thermal and electrical energy – for avionics, sensors, weapon systems and cooling.
The key to this is the Variable Cycle Engine (VCE) concept. It allows the engine to switch flexibly between efficiency and performance depending on the flight profile – a quantum leap compared to today’s engines.
Network-centric warfare: everything is networked – and multifunctional
Gone are the days when a radar was just a radar, a jammer was just a jammer and a radio was just for voice.
Today, transceiver antennas based on gallium nitride (GaN) semiconductor modules in combination with software-defined transmitter and receiver units enable a completely new level of versatility.
One and the same system can – depending on requirements – act simultaneously as a radar, electronic jammer and as a beam-guided radio data transmission device. This reduces weight, saves space and turns the aircraft into a highly networked node in the digital battlefield.
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Communication without traces
Radio silence is ideal – because every active emission can be located by the enemy. Nevertheless, a 6th generation fighter aircraft must constantly receive and transmit information. In order to remain undetected, only the minimum amount of energy is used for transmission – targeted and precise. Since the position and direction of allied units are known, the radio beam can be precisely aligned to them – with the lowest possible transmission power and a narrow beam angle.
This also applies to communication with satellites. Here, too, the following applies: those who transmit broadly and strongly risk being detected by enemy spy satellites. On the other hand, targeted and precise transmissions remain hidden.
And there will be a lot to transmit: As a supersonically fast, fully networked multispectral sensor platform, a 6th generation jet will become a flying reconnaissance node. It provides real-time data far beyond the capabilities of classic airspace surveillance – not only for its own fighter aircraft, but also for ground troops, ships and even units in low-Earth orbit.
Even more than an F-35, the 6th generation will become the control center in a battlefield that is networked across all domains.
Sensors: See without being seen
The growing effort to avoid own signatures and suppress any unnecessary emission is offset by highly developed sensor technology that can detect even the smallest traces – in all relevant frequency ranges.
Whether optical or radar-based detection, heat signatures or electromagnetic emissions: Every trace, no matter how faint, is recorded, analyzed, compared with extensive databases and precisely identified.
The system recognizes what is flying, driving or swimming – and classifies it in fractions of a second. The aim is not only to detect threats at an early stage, but also to provide a complete, networked picture of the situation in real time – without being detected.
Signature hunting – even in peace
Signatures are always collected – not only in an emergency, but also in peacetime. From the laser beam of a rangefinder to the radar signature of a guided missile seeker: every signal reveals something about its origin.
Such emissions can often be passively located and analyzed in the network – without transmitting themselves. Ideally, this even enables precise localization, identification and ultimately fire control – unnoticed, at a great distance and without having to activate your own active sensors.
Drone control: The faithful wingman
Manned fighter jets are increasingly operating in conjunction with unmanned aerial vehicles. These so-called Collaborative Combat Aircraft – also known as “Loyal Wingman” – fly along, but often also ahead.
Equipped with sensors, electronic warfare and precise weaponry, they perform reconnaissance, deception, target marking or the first strike – often in places where the risk would be too great for manned systems. The 6th generation not only thinks about swarm combat – it is built for it.
The relationship between man and machine: it’s all in the mix
The ratio of manned and unmanned systems to be procured is still unclear. Simulations on high-performance computers and findings from realistic maneuvers should shed light on this. But one thing is already clear: Losses are being calculated – especially on the part of the unmanned wingman. Their comparatively inexpensive production allows them to be used in high-risk scenarios where the protection of human pilots is a priority.
Artificial intelligence: turning data into decisions
The highly sensitive sensor technology – distributed across manned jets and unmanned escort drones – generates a huge flood of data. This must be analyzed, evaluated and converted into usable information in real time: for target identification, for forwarding to the network or for the direct use of weapons.
Artificial intelligence pre-filters these volumes of data – deciding what only needs to be transmitted to the combat network and what needs to be displayed in the pilot’s cockpit. It prioritizes the threats, supports tactical decisions and ensures that humans retain an overview.
But one thing remains unchanged: The final decision – whether to shoot or not – is always made by a person.
Stand-off weapons against ground targets: Attack from a distance
Modern, multi-layered air defense systems are making it increasingly difficult even for stealth fighter aircraft to penetrate the close range of their targets. The answer to this is precise stand-off weapons that can be deployed far in advance of the actual combat zone.
One example is the new Stand-in Attack Weapon (SiAW) of the US Air Force. It is designed to enable aircraft to attack enemy radar positions and air defense systems from distances of over 200 kilometers – without coming within range themselves. SiAW belongs to the class of Air-Launched Ballistic Missiles (ALBM), i.e. air-launched ballistic missiles. Prominent examples of this type are the Russian Kinschal and the Israeli Air Lore – potentially hypersonic and therefore extremely difficult to defend against.
At the same time, a new generation of cruise missiles is being developed: smaller, lighter, cheaper, more versatile and faster to manufacture. Systems with names such as Barracuda or Comet are to be available in large numbers – designed to overwhelm enemy air defenses through sheer mass and effectively take out even well-protected targets.
Smaller, faster, further: next-generation air-to-air missiles
A new European development program is currently dedicated to a future short-range air-to-air missile: the Future Short-Range Air-to-Air Missile (FSRM). It is to be specially tailored to the requirements of the 5th and 6th generation. The operational specifications have not yet been conclusively defined – but one conceivable capability could be the targeted use against enemy missiles.
Developments are also underway on the US side: With the Peregrine from Raytheon and the Cuda from Lockheed Martin are medium-range missiles that take up only half as much space as an AMRAAM with a comparable range – and are designed to fly faster.
A two-stage design is emerging for the next generation of long-range missiles, such as the Long-Range Engagement Weapon (LREW). As far as range, speed and flight altitude are concerned, much remains secret – or simply spectacularly speculative. One thing is certain: the future of these weapons will be multi-stage, faster and more intelligent – and will operate well beyond today’s standards.
Lasers: light as a weapon
Focused light is right at the top of the technological agenda – the use of lasers in aerial combat is no longer considered science fiction, but a foregone conclusion.
Compact laser systems for self-defense already exist: they are powerful enough to blind or even damage the infrared seeker heads of approaching missiles. However, high-energy lasers in the 100 kW range, with the potential to shoot down missiles or drones, still require considerable technical progress. At present, such systems require space and weight in the order of a truck – so they are not (yet) an option for fighter aircraft.
However, development is progressing rapidly. Miniaturization, new energy sources and thermal management could soon produce ready-to-use systems.
Energy is not the problem – space and weight are
Providing the necessary energy for laser weapons appears to be the least problematic in technical terms. For comparison: the F-35B’s lift fan, which ensures hovering flight, is driven by a shaft with almost 25,000 kW – at the same time, the engine delivers a comparable amount of energy via the thrust nozzle.
The sheer power of modern engines has therefore long been sufficient to supply powerful lasers. The real challenge lies elsewhere: in the limited space and weight that can be planned for such systems in aircraft design. For the time being, these factors will determine how powerful and operational laser weapons will actually be.
