Next-Generation Air Dominance prototype?

A former British technical liaison for Washington reflects

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This piece has been prompted by reports that the USAF has already flown a demonstrator of the first stage of its Next Generation Air Dominance Fighter.

The US programme is a bold and innovative attempt to break the mould of increasingly long and complex development cycles for advanced military aircraft. This would include the approach of using virtual prototyping, modelling and assessment to evaluate systems before building physical hardware. This approach offers the potential to identify and correct issues before committing to physical prototyping, as well as the prospect of a more rapid iteration to an implementable design.

The intent is to develop and field new versions, and adaptations, of a family of systems, taking advantage of virtual prototyping, so that anticipated rapid advances in software-driven capability can be more rapidly accessed. It is also clearly anticipated that the NGAD capability will not simply reside in one super-platform, but will be delivered by a system of co-operating platforms and systems.

Two years ago, in a piece for Hush-Kit on Air Power in 2030, I suggested the following for the future direction of US Air superiority, then referred to as F-X:

US - future systems

As we have seen from the earlier discussion, there is an emerging capability gap around USAF air superiority systems, given the lack of a programme for a capability upgrade to the F-22. A replacement programme, F-X, is in existence, but little hard information is available. There is also a lack of clarity about future US Navy plans to replace the F/A-18 E/F/G under the F/A-XX programme.

USAF 6th Generation Fighter F-X

Role: Air Superiority (Penetrating Air Combat)
Configuration: Unknown
2018 Status: In development (?)
2030 Status: Entry to service

The limited information available suggests that the USAF is seeking a system-of-systems approach, where a range of sensor, communications, electronic, cyber, platform(s) and weapons would deliver its future capability. There is an indication that the platform element of this would have significantly greater range and payload than the current F-22, while retaining the ability to be both stealthy and supersonic.

One enabler for this is seen as the use of variable cycle propulsion systems, offering modes at higher bypass ratio for the cruise, and lower bypass ration for take-off, acceleration and dash. Adjunct systems are likely, and might include long-range ground-based air defence systems; stand-off, and possibly space-based, sensor systems; and, speculatively, some autonomous systems which might deliver targeting, communications relay or EW capabilities.

Given US conviction of its superiority in LO technologies, this aspect is likely to be emphasised. Consequently, I would not anticipate a J-20 style solution as the US believe canards too much of a compromise in this area. There has been substantial research in unconventional control devices for LO systems, and there is a US desire to avoid vertical tail surfaces if possible.

Based on all this – a large highly swept delta, with minimal tail surfaces, and active use of innovative control systems appears likely. To be effective, such a platform would need to carry highly effective and long-range AAMs, and would be supported by networked detection, tracking and targeting systems, as well as stand-off electronic warfare and cyber capabilities.

Prototyping, technology development and risk reduction activities are likely to be taking place, possibly as Black programmes.

I’d stand by all this, which seems to reflect closely what is known of the NGAD programme so far.

The mechanism for rapid development and evolution of the system, and presumably its other components too, is credible. It certainly resembles the aspirations of others in this field (BAE Systems were trialling an approach called GHOST, based on virtual prototyping, 20 years ago).

Because such a high proportion of the proposed capability will be software-enabled, it is likely that any NGAD platform, sensor or system will be dependent, not only on the robust development and validation of its initial code, but progressive development will require multiple further software developments and enhancements, not just on individual platforms and sensors, but also on other elements of the integrated system-of-systems.

This will place great emphasis on getting the initial architecture right, and ensuring that the entire system-of-systems is robust as additional capability is added. In my view software development, integration and validation has been the most under-rated risk in the JSF programme, and hence has been the area to which many delays can be traced. Perhaps this is the key technical challenge in the programme, and it is certainly critical if the pace of development is to be rapid.

Organisationally, however, real progress in shortening design cycles is also dependent on shortening the parallel Military, Defense Department, and Congressional decision-making cycles, which may actually pace such programmes. This is, perhaps, a second area where a real break-through is required.

Other elements to stress would be the intent to build a cyber-warfare (and cyber-resistant) networked capability, and the extensive use of off-board sensor, EW, communications and possibly weapons platforms. Extensive use is likely of data and information fusion, to allow targeting of, and by, third parties, and also (as outlined in another Hush_Kit article by myself and Dr Ron Smith link) to allow cooperative detection and targeting of stealthy combatants.

The Loyal Wingman, in development by Boeing in Australia, is but one of a number of emergent UAV projects which might provide adjuncts to the manned NGAD capability. While significant attention has been given to the potential use of LO UAVs as strike platforms, their use as air combat weapons carriers, and additional sensor platforms, is certainly not out of the question.

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This area has been examined in the past – while no one bought into a fairly widely-touted Lockheed Martin proposal for an unmanned F-16 some decades ago, research efforts in the UK, and doubtless the US and others, have examined unmanned co-operating air-to-air combat UAVs in the past. With the technology capabilities for third-party targeting, data-linking, and co-operative use of sensors already fielded in the F-35 and other current platforms, it seems more than ever a plausible option. Indeed, the BAE Systems LANCA (Lightweight Affordable Novel Combat Aircraft) project, which is itself part of the Tempest programme, explicitly foreshadows the use of adjunct systems in air combat.

Implementing armed air-combat UAV wingmen would require permissive rules of engagement, but with an explicit aspiration of Global Air Dominance, one can easily imagine the US going down this path.

It is likely that advantage will be taken of the inherently large usable internal volume of delta configurations to carry, not only fuel for long range, but also probably multiple weapons bays, enabling both an anti-air and a strike capability. It would not be surprising if the weapons bays were quite large, allowing the flexibility to accommodate future hypersonic weapons. Similarly, it may be expected that early iterations of the design would have additional internal bays set aside for future sensors, growth avionics and computing capability, to provide a sound basis for future evolution of the capability.

A second input to this discussion of the NGAD system comes from the slide below.

I find myself in pretty broad agreement with the suggestions in the slide, except the indication that the platform might be hypersonic. Hypersonic systems with warfighting capability still appear to be difficult in a number of areas including propulsion, sensors, weapons carriage and release, not to mention materials and structures.

From a cost and time point of view, the whole direction of the programme appears to be reliant on multiple incremental steps rather than large leaps of faith such as might be required to take on manned hypersonic air combat. Finally, any hope of Infra-Red stealth would disappear with the aerodynamic heating experienced in atmospheric hypersonic flight. This is not to say that a hypersonic boost-glide vehicle might not be part of the mix for a future USAF. I just can’t see such a system coming out of this type of programme.

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Similarly, I am sure that the NGAD system will have some laser capability, as laser dazzle systems are already widely available (although packaging for a stealthy fighter might still be a development area). I am less convinced that the technology for airborne weapons capability is available, but the incremental approach adopted is presumably intended to allow for future developments like this, should they become available.

Finally, I believe the US would seek to avoid the use of the canard surfaces shown, and would prefer other means of controlling the aircraft. The requirements for control are likely to be quite different from those of current air superiority fighters. Given the intent to operate as a system of systems, one might envisage a fully developed NGAD platform operating as the command and control node, using cooperating unmanned sensor, EW and weapons platforms to deliver both a permissive environment and, as far as possible, weapons effects. The principle role of the crewed NGAD platform would be to provide human-in-the-loop decision-making, enabling the whole system to respond to the mission situation and threat response.

The NGAD platform itself would be optimised for stealth rather than manouevrability, and, I suggest, would only seek to engage in BVR air combat, and perhaps strike using stand-off weapons. Consequently, control requirements are unlikely to include aggressive manoeuvring, dog-fighting, and high-g manoeuvres. Instead, the emphasis is likely to be on providing effortless and largely automated control, using stealthy effectors, and freeing up crew attention to manage the tactical system-of-systems.

These effectors might include thrust vectoring, vortex flaps, and a number of emerging technologies, possibly including air jets as in the BAE Systems MAGMA project, circulation control, or shape-changing structures.

Differential flap or airbrake deflections are another feasible approach, but would probably be avoided in the interest of maintaining low signature.

For completeness, I attach my thoughts on the US Navy F/A-XX program, also from 2018:

F/A-XX

Role: Multi-role (Air Defence, Strike, EW)
Configuration: Unknown
2018 Status: In development (?)
2030 Status: Entry to service

The F/A-XX program reflects a US Navy need to replace the F/A-18 E, F, and G in the mid-2020s as these platforms reach their service lives. Compared to the USAF requirement for a 6th gen fighter, the future F/A-XX is likely to constrained by carrier deck size and possible weight constraints, and also by the necessity to operate within the deployed environment of the carrier battle group.

The available material discussing the project expresses similar aspirations to F-X in terms of the system being networked and integrated with other components in order to achieve the required capability effects. That said, there are suggestions that the US Navy may seek a somewhat more agile system that that proposed for the USAF.

There are some interesting programmatic issues, not least the question as to why the Navy doesn’t simply acquire more F-35C to replace the Super Hornets. My guess is that the Navy will seek to have a program which draws on the technologies being developed for F-X, but will seek to acquire a Navy-specific solution rather than a common system.

On configuration, I think a Navy F/A-XX would be smaller and more agile than the Air Force F-X. It will also need compromises to be made to achieve the deck landing and take-off requirements, and these may result in a somewhat less stealthy solution than the F-X.

Prototyping, technology development and risk reduction activities are likely to be taking place, possibly as Black programs.

An interesting aspect of Blue-Water Navy operations is the likely need for an autonomous, and preferably stealthy, refuelling system to enable CAP patrols of worthwhile duration and stand-off, to assist in providing Air Defence for the Task Group. This requirement may be a driver for the early development of such a capability, with active programs being conducted by the US Navy, USAF, Airbus, and in China.

Jim Smith

Jim Smith had significant technical roles in the development of the UK’s leading military aviation programmes from ASRAAM and Nimrod, to the JSF and Eurofighter Typhoon. He was also Britain’s technical liaison to the British Embassy in Washington, covering several projects including the Advanced Tactical Fighter contest. His latest book is available here.

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