A sixth-generation jet fighter is a conceptualized class of fighter aircraft design more advanced than the fifth-generation jet fighters that are currently in service in and in development in several countries, including China, United States, Russia, France, Japan, United Kingdom and Germany. In 2018, China’s aircraft development program under the command of AVIC has unveiled the AVIC 601-S dubbed the Dark Sword, which is widely regarded as potentially the world’s first sixth-generation military fighter jet, with the aid of AI technology. The United States Air Force (USAF) and United States Navy (USN) are anticipated to field their first sixth-generation fighters in the 2025–30 time frame. The USAF is pursuing development and acquisition of a sixth-generation fighter through the F-X program to replace its existing aircraft such as the McDonnell Douglas F-15 Eagle and complement existing platforms in service such as the Lockheed Martin F-22 Raptor. The USN is pursuing a similar program called the Next Generation Air Dominance, likewise intended to complement smaller Lockheed F-35 and replace its existing aircraft such as the Boeing F/A-18E/F Super Hornet.
United States of America
On October 10, 2012, Under Secretary of Defense for Acquisition, Technology and Logistics Frank Kendall justified the need to start the program.
The Pentagon 2015 budget request has studies to lead to an acquisition program in fiscal year 2018.
Frank Kendall revealed that funding for initial sixth generation fighter development would be requested in the FY 2016 budget. Next-generation fighter efforts will initially be led by DARPA under the “Air Dominance Initiative” to develop prototype X-planes. The agency as well as industry are known to have started internal research on potential sixth generation technologies for several years. Kendall confirmed that Navy and Air Force will each have variants focused on their mission requirements.
In 2016 the USAF announced a change of course to pursue “a network of integrated systems disaggregated across multiple platforms” rather than a “sixth generation fighter” in its Air Superiority 2030 plan.
Dubbed the “Next Generation Tactical Aircraft”/”Next Gen TACAIR”, the USAF seeks a fighter with “enhanced capabilities in areas such as reach, persistence, survivability, net-centricity, situational awareness, human-system integration and weapons effects,” a November 4, 2010 presolicitation notice states. “The future system will have to counter adversaries equipped with next generation advanced electronic attack, sophisticated integrated air defense systems, passive detection, integrated self-protection, directed energy weapons, and cyber attack capabilities. It must be able to operate in the anti-access/area-denial environment that will exist in the 2030–50 timeframe.”
The sixth-generation fighters are expected to use advanced engines such as Adaptive Versatile Engine Technology to allow longer ranges and higher performance. Risk reduction began in 2012 so that engine development can start around 2020. An engine is to be ready when fighters are introduced by the Navy in 2028 and the Air Force in 2032.
In November 2013, the Air Force Research Laboratory released a request for information (RFI) for a laser weapon that could be mounted on next-generation air dominance fighters by the 2030s. The Air Force is interested in three categories of lasers: low-power for illuminating, tracking, targeting, and defeating enemy sensors; moderate-power for protection to destroy incoming missiles; and high-power to offensively engage enemy aircraft and ground targets. The laser and systems controls are to work at altitudes from sea level to 65,000 ft at speeds from Mach 0.6 to Mach 2.5. Laser submissions are to be at technology readiness level 4 (basic components work in a lab) by October 2014, and the Air Force wants a system to be at technology readiness level 5 (system components work in a simulated environment) or higher by 2022. The RFI requests submissions with detailed descriptions in a militarily useful configuration, potential problems and solutions, and cost estimates.
The RAND Corporation has recommended that the U.S. military services avoid joint programs for the development of the design of a sixth-generation fighter. Studies by RAND have found that in previous joint programs, different service-specific requirements for complex programs have led to design compromises that raise costs far more than normal single-service programs. In a comparison between four recent joint service programs (F-35, Joint Strike Fighter, T-6A Texan II Joint Primary Aircraft Training System, E-8 JSTARS, V-22 Osprey) and four recent single-service programs (C-17 Globemaster III, F/A-18E/F Super Hornet, F-22 Raptor, T-45 Goshawk), costs for joint programs rose 65 percent nine years after a Milestone B decision to move into engineering and manufacturing development compared to 24 percent for independent programs during the same timespan.
Engine development for sixth generation fighters is already underway to be more efficient in making jets faster and giving them a longer range. While current engines operate best at a single point in the flight envelope, newer engines could vary their bypass ratios for optimum efficiency at any speed or altitude. That would give an aircraft a much greater range, faster acceleration, and greater subsonic cruise efficiency. A variable cycle engine could configure itself to act like a turbojet at supersonic speeds, while performing like a high-bypass turbofan for efficient cruising at slower speeds; the ability to supercruise may not be a critical requirement, but it will likely be able to with the engine type. One critical component is the adaptive fan to allow the engine to vary its bypass ratio depending on altitude and speed with a third stream of air to increase or decrease the bypass ratio. A low-bypass configuration would be used for take offs and supersonic flight, and a high-bypass configuration would have high propulsive efficiency for cruising. The U.S. Navy and Air Force have different sixth generation fighter development programs, but both services are working together on engine development. The Air Force is aiming for a Milestone A decision by 2018, with a production version to be ready possibly by 2021. Companies involved with next-generation engine development include General Electric and Pratt & Whitney.
On 30 July 2014, General Mike Hostage spoke about the evolving nature of proposed sixth-generation fighter requirements at an event hosted by the Air Force Association (AFA). Since Air Combat Command released a request for information (RFI) in 2009 for industry feedback on sixth-generation air dominance technologies, teams thinking of requirements have been told not to think in terms of a “platform” like a single-seat fighter with a certain number of engines. Hostage remarked that if next-generation air dominance capabilities came from pressing “a single button on a keyboard that makes all our adversaries fall to the ground” it would be acceptable. Concepts from the Air Force and industry have so far revolved around supersonic tailless aircraft. One of the key limitations in relying on a single platform is they have a limited weapons load, so the original RFI sought ground-based and non-kinetic solutions, with whatever sixth-generation technology being required to have a larger magazine than current fighter solutions.
There are significant differences between Navy and Air Force visions for their respective next-generation jet concepts, but both agree on some fundamental characteristic aspects they will share. American sixth-generation fighters are to feature artificial intelligence as a decision aid to the pilot, similar in concept to how advanced sensor fusion is used by the F-22 and F-35. They will also have Positioning, Navigation, and Timing (PNT), and communications that allow big data movement between both service’s aircraft.
Air Force General Herbert Carlisle said in February 2015 that stealth is “incredibly important” for their next-generation F-X fighter. This contrasts with statements made by Chief of Naval Operations Admiral Jonathan Greenert that their F/A-XX fighter might not be so focused on survivability as to sacrifice speed and payload. Unlike the previous F-22 and F-35 development programs that depended on new technologies that drove up cost and delayed introduction, the Air Force is intending to follow a methodical path of risk reduction to include as much prototyping, technology demonstration, and systems engineering work as possible before creation of an aircraft actually starts. Carlisle describes the sixth-generation strike capability not as just an aircraft, but a system of systems including communications, space capabilities, standoff, and stand-in options.
In March 2015, the Navy revealed they were working with the Air Force to potentially release joint analysis of alternatives (AoA) in 2016 for their next-generation fighters; they are allowed to take a joint AoA, then define a service solution that would be good for each service. The Navy is focusing on replacing the capabilities of the fighter with a wide range of options for the Super Hornet, as well as the EA-18G Growler. The AoA will run parallel to several other design and technology efforts including engine technology, airframe molds, broadband and IR stealth, and new ways to dominate the electromagnetic spectrum. Part of the Navy’s calculus will be based on how the F-35C performs as a critical forward sensor node for the carrier air wing. How the fifth-generation F-35C integrates with the rest of the air wing to give greater capabilities than what the platform itself can do may lend itself to the sixth-generation F/A-XX.
In April 2015, the Center for Strategic and Budgetary Assessments (CSBA) released a report concluding that the next-generation U.S. Air Force fighter should be larger and more resembling a bomber than a small, maneuverable traditional fighter. It analyzed over 1,450 air-to-air engagements since 1965 and found that long-range weapons and sensors have dramatically decreased instances of dogfighting. With the increase of air defense systems using electronic and infrared sensors and high-speed weapons, traditional designs relying on small size, high speed, and maneuverability may be less relevant and easier to intercept. As a result, the CSBA suggests building a fighter significantly larger relying on enhanced sensors, signature control, networked situational awareness, and very-long-range weapons to complete engagements before being detected or tracked. Larger planes would have greater range that would enable them to be stationed further from a combat zone, have greater radar and IR detection capabilities, and carry bigger and longer-range missiles. One airframe could be fitted with various attachments to fill several roles. The concept of a small number of large, intercontinental and heavily armed combat aircraft could link itself to the development of the Long Range Strike Bomber.
In November 2016 the USAF Scientific Advisory Board announced studies for a Penetrating Counter Air (PCA) platform that would combine long range, supersonic speed, stealth and maneuverability and be fielded by 2030. PCA would have substantially longer range to fly long distances over the Pacific, especially in a situation where airbases in the vicinity of China are not available or if aerial tankers are destroyed. It would also escort bombers deep into Russia or China, where the anticipated threat includes advanced networked air defense radars. It would include stealth against low or very high frequency radars (like those of the S-400 missile system), which requires an airframe with no vertical stabilizers. Another requirement is significantly larger payload than current air superiority aircraft like the F-22. Adaptive cycle engine technology is an option under consideration for the PCA, given the fact that the alternative would be a very large aircraft.