Aviation Week
Future Bombers Under Study In China And Russia
Aviation Week & Space Technology
Bill Sweetman Richard D. Fisher
Thu, 2014-09-18 11:06
China may follow Russia in bomber developments
A version of this article appears in the September 15 issue of Aviation Week & Space Technology.
While the U.S. Air Force pursues development of the Long-Range Strike Bomber project, striving to launch full-scale development next year, both Russia and China are also proceeding with bomber plans. In the case of Russia, the PAK-DA (perspektivnyi aviatsionnyi kompleks dal’ney aviatsii, or future long-range air system) is the first all-new bomber to start development since the Tupolev Tu-160, in 1977, while China’s prospective new system would be the nation’s first indigenous bomber.
PAK-DA is under development by the Tupolev unit of United Aircraft Corp. (UAC), which has been responsible for almost all of Russia’s long-range bombers since the end of World War II. The basic decision to pursue development of a new bomber was taken in 2007. At that point, the Russian military started to define upgrades to the existing bomber force, which would bridge the gap until a new aircraft could be ready, alongside an analysis of alternative configurations and approaches.
Out of dozens of potential candidates, including supersonic and hypersonic technologies, four finalists emerged, and a preferred design—featuring a subsonic all-wing or blended-wing body with stealth characteristics—was submitted to the customer in early 2012. It is likely to be the first Russian aircraft designed with all-aspect, broadband stealth—the key feature introduced by the B-2 when it entered service in 1997.
It was reported late last year that a final decision to build PAK-DA had been taken, with work to start in 2014. UAC has now been awarded the design and integration contract for the PAK-DA, and the bomber is due to make its first flight in 2019, with final assembly to take place at UAC’s Kazan plant. It is expected to complete its state acceptance tests in 2023 and enter service in 2023-25, according to the most reliable Russian reports. Earlier this year, United Engine Corp.’s JSC Kuznetsov unit, which has powered most of Tupolev’s bombers, was selected to develop the PAK-DA’s engine, based on components from the Tu-160’s NK-32 afterburning turbofan.
Beyond that, very little about PAK-DA has been released. However, it is possible to make some educated guesses about the program, based on the size and shape of the Russian bomber force and the new aircraft’s likely missions.
The current long-range bomber force comprises a scant squadron of Tu-160s (a total force of 13 aircraft), 63 subsonic Tu-95MSs, built in the early 1980s as cruise-missile carriers (31 are MS16 versions with underwing pylons, and 32 are MS6s without), and a diminishing number of Tu-22M3 Backfires, most of them originally built to attack U.S. aircraft carriers and their supporting groups. The Tu-22M3 force assigned to theater-range land-attack missions is being replaced by the smaller but more versatile Sukhoi Su-34.
The Russian defense ministry announced in early 2012 that the Tu-160s would be modernized by 2020 and redesignated Tu-160M. This followed a 2009 decision to update the Tu-95 fleet, under the designation Tu-95MSM. Both upgrade programs are extensive, featuring new radars—from the same Leninets series used on the Su-34—and improvements to electronic warfare, displays and processors, which currently use 1980s technology. The Tu-160M was reported to be ready for state acceptance trials at the end of 2013.
The upgrades also include life extension, which covers investment in new engine overhaul capabilities, the renewed production of NK-32 engines for the Tu-160 and the design of a longer-life, more reliable engine variant. In 2010 the Russian government announced an investment of more than 8 billion rubles ($220 million) for this program through 2020. The preproduction batch of new NK-32 engines is expected to be ready in 2016. These upgrades also will provide the foundation for the PAK-DA’s engine.
Both bombers are being armed with a longer-range air-launched cruise missile (ALCM). Russia has had two major ALCM projects since the early 2000s, both from the Raduga division of Tactical Missiles Corp. The Kh-555 is a conventionally armed ALCM produced by modification of the 1980s-era Kh-55 nuclear weapon, with a combined inertial, radar-based terrain matching and infrared scene-matching guidance system.
The same company’s all-new and larger Kh-101/-102 (conventional and nuclear versions respectively) is now in full production. The Tu-160 can carry 12 weapons internally and the Tu-95MS can carry eight, on four dual-wing pylons. It is the largest ALCM in use, with launch weight estimated at up to 5,300 lb. Originally planned to be an ultra-long-range missile with a prop-fan power unit, it now has a turbofan on a retractable mount, similar to the Kh-55. The current inventory of long-range cruise missiles numbers 850 weapons.
This extensive upgrade work indicates that the older bombers are expected to serve for at least 5-10 years after the PAK-DA enters service, with the new aircraft presumably being assigned the role of a penetrating bomber.
The announcement that the new bomber’s engine is to be based on the NK-32, together with the fact that Russian bombers traditionally rely less on inflight refueling than the U.S. Air Force’s designs, points to a large aircraft. The NK-32 is a three-shaft, low-bypass-ratio engine that produces 31,000-lb. thrust in military power and 55,000-lb. thrust with afterburning. The variant being developed for the PAK-DA will be a non-afterburning engine, possibly with a slightly increased bypass ratio. Four such engines would indicate a gross weight of 200 metric tons, larger than the B-2 (and most likely much bigger than LRS-B), corresponding to a greater weapon load and range.
Meanwhile, China is reportedly working on a new bomber. It is tempting to discount China’s ambitions to build a world-class strategic strike aircraft given that its People’s Liberation Army Air Force (Plaaf) and Naval Air Force (PLAN-AF) seem content to fly successive versions of the Soviet-era Tupolev Tu-16. This medium bomber first flew in 1952 and then in China in 1959, subsequently built by the Xian Aircraft Corp. (XAC) as the Hong-6 (Bomber-6, H-6). However, continued improvements and production of the H-6 show that China retains an interest in long-range airpower.
China’s government and People’s Liberation Army (PLA) say virtually nothing about their future bomber ambitions, but an accumulation of “gray data” plus a recent revelation indicate it is likely that China is developing a new bomber. Last April an Asian government source disclosed an estimate that China’s next-generation bomber, called H-20, would emerge by 2025.
Such timing for the emergence of the H-20 would be consistent with two evolving Chinese strategic objectives. A new bomber would extend China’s ability to deny strategic access to the U.S. well beyond the “first island chain,” extending through Japan, Taiwan and the northern Philippines and encompassing the northern and southern China Sea.
Secondly, this aircraft would aid the Chinese leadership’s ambitions to project military power. Such a platform would allow the Chinese air force to complement the gathering global aircraft carrier and amphibious projection capabilities of the nation’s navy.
China’s next-generation bomber has long been rumored by informal Chinese sources to have been under development since the mid-to-late 1990s. Chinese determination to proceed was likely strengthened by the use of the Northrop Grumman B-2 in the mistaken bombing of the Chinese Embassy in Belgrade on May 7, 1999. It is also unclear how much data about the B-2 China was able to obtain from Northrop Grumman engineer Noshir Gowadia, who, in his 18 years with the company, was one of the principal designers of the B-2’s low-observable propulsion system. In January 2011 he received a 32-year sentence for conveying military secrets to China.
The Xian Aircraft Corp. (XAC), the PLA’s main large military aircraft manufacturer, is most likely the lead contractor for the new bomber. Like the next-generation bombers from Russia and the U.S., the H-20 is expected to use a subsonic low-observable “flying wing” configuration.
Interesting but unofficial indications have also been provided by PLA academics. Chinese media reports from October 2013 quote Plaaf Col. Wu Guohui, an associate professor at the National Defense University, saying stealth bombers had received “renewed national attention” and that “in the past China has been weak regarding bombers, but in the future will develop long-range strike aircraft.”
National Defense University Associate Prof. Fu Guangwen noted in a December 2013 interview that bomber development in China faces several obstacles, including challenges in developing engines and effective materials. But he then noted that a future Chinese bomber should be able to cover targets out to the second island chain, Guam, the South China Sea and India; be stealthy to improve penetration capability; be capable of “information confrontation,” or cyber/electronic warfare; and have conventional and nuclear strike capability.
A January 2014 Sina.com article cited an Aviation Industry Corp. of China publication, stating that design work on a future Chinese stealth bomber had started in 2008. This report also noted that this bomber was likely a flying wing and that it would have the range to strike the U.S. West Coast.
Though it falls under the category of ambiguous “gray data,” in early 2013 an image from a Chinese academic engineering journal showed a potential bomber shape very similar to the B-2. In early 2014 another Chinese image emerged of two bat-wing-shaped model aircraft, possible radio-controlled models for test purposes. There is no other information to connect these models to ongoing programs, but it is well established that China formally previews models of future military aircraft, while leaked model images are often aimed at domestic and foreign audiences.
The later models could also represent new long-range unmanned combat aerial vehicle (UCAV) shapes, which also highlights the potential for China to develop long-range unmanned strike aircraft. With some fanfare in the Chinese media, the flying swept wing LiJian (Sharp Sword) UCAV, a collaborative product of the Shenyang and Hongdu companies, took to the air Nov. 20, 2013. Similar in size and shape to the Boeing X-45C, indications are that LiJian has provided the basis for longer-wingspan UAV/UCAVs from Shenyang/Hongdu, some Chinese sources suggest. It is conceivable that Xian might eventually develop an unmanned version of the H-20, especially if Russia and the U.S. were to so develop their new bombers.
Possible Chinese interest in a new supersonic regional bomber was signaled in the early May 2013 emergence of a model of a new low-observable-shaped twin-engine bomber, which appeared next to a model of the known LiJian. With an estimated length of 25-30 meters (82-98 ft.), this bomber appears to approach the late-1950s Convair B-58 (the largest Western purpose-built supersonic bomber to enter service) in size. However, available information cannot confirm whether it is an active program, the loser of a previous competition or an unfunded concept.
Although PAK-DA is overtly a strategic deterrent system with the aim of holding U.S. targets at risk, it is unlikely that any new Chinese bomber would be intended for a parallel role. However, a long-range, survivable platform with a large missile payload would be a powerful regional asset to threaten adversary land bases and naval forces, particularly in conjunction with supersonic, stealthy J-20 fighter/strike aircraft.
The PLA continues to develop new versions of the H-6 and to upgrade older models with new weapons. Likely spurred by early 1990s Russian refusals to sell the Tupolev Tu-22M3 (although requests were definitely conveyed by the 2003-04 period), the PLA opted to develop a radically upgraded version of the H-6.
The H-6K is fitted with the Russian-supplied 26,500-lb.-thrust UEC-Saturn D-30KP-2 turbofan, which is approximately 30% more powerful than the 1950s-vintage turbojets of the earlier versions and is more efficient, with a higher bypass ratio (2.24:1) than the JT8D-200. This increases combat radius to a reported 3,500 km (2,175 mi.). Emerging in early 2006, the H-6K replaced the old glazed nose with a large radome and electro-optical targeting sensor. The aircraft featured a modern glass cockpit and gained six wing pylons to carry new 1,500-2,000-km-range CJ-10/KD-20 land-attack cruise missiles. This version is likely able to use the great variety of precision-guided bombs now produced by four Chinese companies.
China has also upgraded older H-6s. The air force’s three regiments of H-6Gs may soon be armed with the new supersonic ramjet-powered YJ-12 anti-ship missile with an estimated range of 400 km. The Plaaf’s older H-6Ms are being upgraded to carry two CJ-10/KD-20 land-attack cruise missiles. The previously mentioned Asian government source notes that the PLA has 130 H-6s in 2014, but this number could grow to 180 by 2020. This could indicate a longer production run for the H-6K, which currently serves in two Plaaf regiments.
The future of long-range strategic bombing for the PLA is also tied to the development of efficient aerial refueling tankers. In March-April, the Plaaf modestly increased its refueling platforms with the acquisition of three Ilyushin Il-76MDs that had been converted to Il-78 tankers in Ukraine. These carry up to three of the Russian UPAZ drogue-hose refueling system, whereas the previous fleet of approximately 24 converted H-6U tankers carry much less fuel and have only two hose-drogue units. These are the RDC-1 design, derived from the British Flight Refueling Ltd. (now Cobham) FRL Mk 32 acquired in the mid-1980s.
Future tanker platforms may include converted Xian Y-20 heavy transports, versions of the Comac C919 airliner, or a variant of the future widebody transport that has been a subject of Russia-China collaborative discussions.
But to make future tankers more efficient, and more compatible with larger aircraft, China may also be evaluating flying-boom refueling systems capable of higher transfer rates. In a 2013 conference paper, three engineers from the School of Electronics and Information at the Northwest Polytechnical University proposed using differential signals from the Chinese Beidou navigation satellite system combined with optical systems to create an automated control system applicable to hose-and-drogue or flying-boom aerial refueling systems.
With Maxim Pyadushkin in Moscow.
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