Though the F-35 is yet to enter front-line service, the Pentagon has already began thinking about what should replace it. A memo by Frank Kendall III, the Under Secretary for Acquisition, Technology & Logistics, was acquired (by the Bloomberg News group) detailing the first step in defining what the next tactical fighter should be.
The document which was reported on the 22 October 2012 shows that $20- $30 million in DARPA (Defense Advanced Research Projects Agency) funds have been earmarked for this concept definition stage. This means a real, albeit humble start to the next generation fighter programme. The 18 month study will invite suggestions from industry, USAF and the US Navy. This follows a 2010 request from Air Force Materiel Command to define a new tactical aircraft (Next Gen TACAIR). The 2010 request stated that the “The envisioned system may possess enhanced capabilities in areas such as reach, persistence, survivability, net-centricity, situational awareness, human-system integration, and weapons effects. It must be able to operate in the anti-access/area-denial environment that will exist in the 2030-2050 timeframe.”
The US has several perceived fighter ‘gaps’ for the future. The most pressing is the Super Hornet replacement, the Next Generation Air Dominance F/A-XX, for which a formal RFI was issued by the navy in April, 2012. The next is the replacement for the F-22, which will is likely to begin to have airframe age issues from around 2025. The longest-lead item is for a F-35 replacement which may be required from the 2050s.
According to the memo: “We should have no preconceived notions about the nature of air dominance a few decades into the future.” This leaves the door wide open to the companies taking part to offer radical ideas.
His statement that “Our ability to design cutting-edge platforms of this type is already atrophying” and Kendall warns of the dangers of prevarication, fearing that the “potential for viable future competition in this area will shrink or be eliminated” . The move is certain to enjoy full industrial support. Following the evaluation, the Pentagon will assess whether any of the candidates should proceed into a prototype phase in which “multiple competing concepts may be demonstrated,”.
The most likely manufacturers to win this are: Lockheed Martin, Boeing or Northrop Grumman. The ongoing problems of the F-35 programme may count against LM, as will Boeing’s enthusiasm to stay in the fighter market. Lockheed Martin Skunk Works has ambitious ideas of the next fighter, and is considering self-healing structures, multi-spectral stealth and faster (possibly hypersonic) top speeds. Boeing has several tail-less delta concepts, which are built around a photonic, rather than electronic avionics system.
Northrop Grumman has repeatedly mentioned DEW (Direct Energy Weapons) as a feature a 6th Gen fighter should include, along with stealth and comprehensive data-linking.
The current trend for manned/unmanned or ‘optionally manned’ (OM) aircraft is likely to be considered, allowing the aircraft to employ the optimum solution for a given mission.
OM may be politically more palatable, than purely unmanned, for USAF still remains staffed at the highest levels by men and women from ‘piloted’ backgrounds, though a purely unmanned aircraft cannot be ruled out. Unmanned aircraft are also increasingly distrusted by the public and media. The crash in a Somalian refuge camp, and the near collision with an airliner (over the same country) has highlighted the alarming accident rate of the present generation of UAVs.
Fully autonomous operations currently have several technical hurdles, though none seem insurmountable. Legal, moral and cultural objections to purely autonomous military aircraft may prove harder to solve. Fully autonomous may be the way to go though, as remotely piloted aircraft become increasingly vulnerable to jamming and hacking technology. According to a BAE Systems spokesperson, the claimed ‘hack-sky-jacking’ of the Lockheed Martin RQ-170 Sentinel over Iran in 2011, was theoretically possible (though he did qualify that “I don’t think that happened in that case”).
Another popular idea is that the next fighter would also be a UAV-controller, having unmanned wing-men or strike assets as required. At the extreme end of the spectrum is the swarm concept, where many tiny aircraft combine forces to create the same effect as one larger aircraft. One solution is a manned aircraft with sensors monitored by ground-based observers, this is essentially a 21st Century version of the World War II gunner crew with different people guarding different hemispheres of the aircraft. The F-35 will have a modicum of this technology, though there is plenty of room for further exploitation. It would certainly be reassuring for aircrew to know that somewhere someone was constantly ‘checking their six’.
Power is likely to come from an engine based on the ADaptive Versatile ENgine Technology (or ADVENT) programme. This radical project, which began in 2007, involves high-pressure ratio compressor systems and active flow control inlets and exhausts. The design goal is to retain the engine performance found on fifth-generation fighters, but to reduce the fuel consumption by 25-30%. The current thrust class being looked at is 20,000lbs – 35,000lbs (9072 to 15876 kg). ADVENT has been followed by Adaptive Engine Technology Development (AETD), with the aim of bridging the gap between the experimental and the practical realization of the technology. At this phase Pratt & Whitney was invited back into the fold, offering an engine incorporating features of the F119 and F135. P&W’s proposed AETD program will lead to demonstration testing of a high-pressure ratio core in early 2016, to be followed by full engine testing of a three-stream adaptive fan and three-stream compatible augmentor and exhaust system.
The exhaust plume will more carefully considered than ever before, both in terms of aerodynamics (where it will be modeled as if it was ‘part’ of the aircraft), and in terms of cooling (for IR stealth) and shape (for radar stealth).
If as intended, the new generation of engines are capable of efficiency in a wide range of speed ranges, then the same might be expected of the aircraft’s aerodynamic configuration. The concept is known as ‘morphing’ and several manufacturers are looking into ways aircraft would achieve this. A ‘smart skin’ is another option, this could include several technologies including chameleon-like visual stealth or infra-red deception camouflage (a lightweight version of the Adaptiv-type currently being developed for armoured vehicles) and embedded or ‘structural’ sensors. This would come at enormous cost, and would certainly increase the maintenance burden.
A major problem, made even harder by the need to stay stealthy is identifying friends from foe, to allow long distance missile shots. In answering this question one IFF (Identification Friend or Foe) specialist said “it will be relatively simple, if you can see them- they’re hostiles.” alluding to the West’s massive advantage in low-observable technology. But this won’t always be the case, one solution (if true stealthy data-liking proves too hard) is smarter missiles that can accurately identify aircraft types and will not hit friendlies. Future missiles for the fighter are likely to be faster, with multi-band guidance.
Another key area is the using of the radar as a weapon, to both ‘fry’ enemy electronic devices and radars with electromagnetic energy, and to broadcast computer viruses.
The long timeframe makes the possibility of a graphene construction possible. Graphene is expected by many to be the next ‘wonder material’ in the aerospace industry. As Nobel-prize winner Prof Andre Geim, noted “It is the thinnest material in the universe and also the strongest ever measured”.
Whatever solution is chosen, the toughest fight this aircraft programme will have in the near-term will be for funding. The US is reluctant to give up its technological lead in fighters, but anyone requesting funding for the new F-?? (F-24 perhaps or F-36?) was previously seen as rocking the boat, and threatening F-35 funding. Things are changing however, and the 6th Gen fighter programmes are gaining momentum.
(article written in January 2013, provided as an introduction to a series of articles to appear on Hush-Kit about Gen 6)