Here Comes Adversary Stealth

Dec. 1, 2012

Ever since the early 1980s, when the Air Force introduced the F-117 fighter, the United States Air Force has held a monopoly on operational stealth combat aircraft. It still does. No other country can go into battle with low observable aircraft such as the B-2 bomber or F-22 fighter. Soon, the US will have another operational stealth fighter, the F-35.

In the past three years, however, three foreign stealth combat aircraft designs—one Russian, two Chinese—have begun flight testing.

Lockheed Martin’s F-35 (above) and China’s new Shenyang J-31 (inset) are almost comically similar, but the Chinese aircraft is no laughing matter. If new foreign fighters turn out to be as stealthy as they look, US air supremacy may be at risk for the first time in decades. (USAF photo by MSgt. Jeremy T. Lock)

While stealth has been the cornerstone of USAF’s air supremacy for some three decades, these recent developments in Russia and China have sparked concern among some that they may well mark the beginning of the end of America’s long and overwhelming stealth supremacy.

For the most part, senior US military officials shrug off the new fighters, asserting that it takes more than simply a stealthy-looking design to achieve low observability.

That is undoubtedly true. Combat-worthy stealth comprises a broad range of technologies, tactics, training, and techniques. It took 20 years to nurse the F-22 from the drawing board to operational status, during which time the Raptor suffered many costly setbacks. Bringing along the new F-35 will also take many years.

During the trial periods of earlier stealth systems, much had to be learned and relearned about materials, electronics, and sensors, not to mention the integration of all of those elements. Mastering the fine points of manufacturing, maintenance, and flight testing also took vast amounts of time, money, and patience.

The F-22 is still increasing in capability. Gen. Norton A. Schwartz, the recently retired USAF Chief of Staff, noted last year that the Air Force is “not backing away” from the challenge of potential stealth opponents and is investing billions in making the F-22 “all that we can make it be.”

Schwartz, in a rare commentary about normally classified capabilities, said the Air Force has “over $2 billion” in stealth research and development accounts. The goal is to develop new technologies applicable to a sixth generation fighter, should such a project ever be deemed urgent.

These advanced technologies, reported Schwartz, include advanced sensors, materials, manufacturing, data links, apertures, high-resolution radars, and the like.

Lockheed Martin’s F-35 (above) and China’s new Shenyang J-31 (inset) are almost comically similar, but the Chinese aircraft is no laughing matter. If new foreign fighters turn out to be as stealthy as they look, US air supremacy may be at risk for the first time in decades. (Photo via

Thus, the appearance of three or four new, seemingly stealthy designs in the hands of near-peer countries is not seen as a “Sputnik moment,” as one top USAF official put it, and doesn’t demand a crash sixth generation technology program for USAF to stay ahead.

Just by looking at them, there is no way to know whether these new foreign fighters have all the ingredients necessary to achieve a true “fifth generation” stealth capability. Some of them, in fact, may fall short of that standard for many years.

However, while the stealth challengers may not pose an immediate threat, they arrived sooner than expected by American intelligence. That fact, coupled with the rapid proliferation of computer technology and cyber espionage, leads some to speculate that the US edge in combat aircraft may be more perishable than US officials are letting on.

The latest Chinese stealth design to make its appearance goes alternately by the names J-21, J-31, and F-60. Asked in September about this fighter, Gen. Herbert J. Carlisle, the commander of Pacific Air Forces, replied that it is a reminder that the US cannot afford to remain static in combat aircraft technology, because competitors are catching up fast.

“With respect to stealth capability, [China is] … behind us, but they will develop and get better, and we certainly can’t rest on our position,” Carlisle said. “We’re going to have to get better.”

What We Know

Russia’s T-50 has thrust-vectoring engines, claimed to be capable of supercruise. Russia and India may build roughly 400 T-50s together and offer more for export. (Sukhoi photo)

China is “first and foremost … making gains that are improving capability and quality,” he said, and this signifies the three-decade advantage USAF has had in stealth isn’t representative of the advantage it will have in the future.

“That kind of time,” in which the Air Force enjoys a 30-year lead, “will not occur again, in my opinion,” Carlisle said.

He said he believes the US will retain a technological advantage in air combat, but the gap between fielded US systems and competitive counterparts will shrink.

“Given … technology transfer, education, and where it’s going, and who’s participating in that, I think the advantages we have will still be there [but] they just won’t last as long,” said the PACAF commander.

The three main air combat challengers—discussed here in the order they appeared—are the Sukhoi T-50 (Russia), Chengdu J-20 (China), and Shenyang J-21/J-31/F-60 (also China).

Russia’s T-50. The T-50 has been touted by Russian officials as a near-equal of the F-22, but with a substantially lower price tag. Russia intends to manufacture the T-50 fighter for its own forces and for the export market, a step Washington ruled out for the F-22.

The T-50 also goes by the name PAK FA, which, in Russian, translates roughly to “prospective new front-line aircraft system.”

The T-50 first flew in 2010. It does, in fact, bear some resemblance to the F-22, and is about the same size as the front-line USAF fighter. Moreover, Russia says the T-50 will be capable of supercruise, a key attribute of the F-22, in which supersonic flight is sustained without resort to use of fuel-guzzling afterburners.

Videos of flight tests suggest the T-50 enjoys only about the same level of maneuverability as seen in Russia’s best fourth generation fighter, the Su-35, and does not approach that of the F-22. Like the Su-35, the T-50 has canards and the ability to vector the thrust of its round exhaust nozzles.

Exposed engine fan blades are a big no-no in stealth design. The T-50’s blades are clearly visible in this photo, though, suggesting Russia has more work to do. (Photo via Russian Internet)

Industry analysts point out that the T-50’s engine fan blades—a huge reflector of radar energy—are not entirely hidden when viewed from the front. Its engine exhausts also show little conformance to basic low observable design, showing none of the “sawtooth” features typical of an American stealth engine.

The engines seen in the now numerous images of the T-50 in flight may not be those that ultimately equip the fighter. However, its two known engine design shortcomings undoubtedly prevent the aircraft from coming close to achieving a radar cross section as small as that of the F-22 or F-35.

Russia and India have a longstanding agreement to cooperate on the T-50. According to Hindustan Aeronautics Ltd., the Indian version will debut in 2020 and begin squadron service with the Indian Air Force in about 2025. A Russian news service forecasts T-50 series production to begin in 2015, with operational status in the Russian Air Force to be achieved as early as 2018.

Russia plans to buy 200 to 300 T-50s. India’s acquisition goal is 144 by the end of 2030.

Including development costs, sources in India pegged the unit cost of the Indian model, called Fifth Generation Fighter Aircraft, or FGFA, at about $140 million in current dollars.

“They [Russia] say they’re going to produce these in numbers,” said one industry expert who declined to be named. “But I think they have more work to do. I’d be surprised if this is not an intermediate step—a concept demonstrator, if you will—toward something else.”

This industry expert asserted that, if Russia does put this design into production as is, then it will have “something which is only stealthy in a fairly narrow range of view.”

PACAF chief Gen. Herbert “Hawk” Carlisle, here greeting Chinese Army visitors, thinks America’s lead in stealth and other air dominance technologies is narrowing. (USAF photo by TSgt. Jerome S. Tayborn)

Given the wait for the T-50, Russia has signed a deal with Sukhoi to buy 48 additional Su-35s—the climax of development of the Su-27 Flanker series—as a bridge to the new fighters. It is not stealthy in the classic sense, however.

Russia has said the more advanced models of the Flanker series enjoy some stealth because of its Digital Radio Frequency Memory, or DRFM. It is an electronic technique that captures radar energy and rebroadcasts it in a different frequency, affording it some means of fooling search and track radars.

Industry experts said DRFM works under certain conditions but is vulnerable to active electronically scanned array, or AESA, radars, such as those employed on the F-22 and F-35, and planned to be part of the next major upgrade for F-15s and F-16s.

China’s J-20. The Chinese J-20, designed by Chengdu Aircraft Industry Group, appeared in late 2010, and it’s still not clear whether the first photos of it on the Internet were released by Beijing itself or were the work of “tailwatchers” keeping an eye on Chengdu’s airport facilities.

Like the T-50, the J-20 bears a resemblance to the F-22, though mostly in its forebody. The intakes seem adapted from those on the F-35. The wing and tail are a departure from other stealth designs and little seems to have been done to reduce the radar cross section of the engine exhausts, although some sawtoothing is evident.

Given the J-20’s length and center of gravity, it likely is not intended to be an especially agile fighter. The emphasis on frontal radar cross section reduction, its long body (longer than the F-22), and spacious weapons bay suggests the J-20 doesn’t have an exact analogy in Western air forces.

Some believe that it may, in fact, be a stealthy strike platform, designed to be just stealthy enough to get close to a target, launch missiles, and retreat quickly.

These capabilities would imply that the J-20 has an anti-base or anti-shipping role. That would be logical, as the US is dependent on aircraft carriers and forward bases for sustained air action in the Asia-Pacific theater.

Chengdu Aircraft Industry Group’s J-20 may not have an analogy in Western air forces. The large, long aircraft seems to be designed for stealthy attack, not necessarily dogfighting. (Photo via

Moreover, Chinese military doctrine emphasizes neutralizing US strengths—such as intelligence, surveillance, and reconnaissance systems and forward bases—early in any conflict.

At a trade show, Chengdu displayed a model of the J-20 with the weapon bays open, revealing a loadout of air-to-air missiles almost identical to that of the F-22.

If the model is accurate, then it could be that the J-20 also has an interceptor mission, to fire volleys of air-to-air missiles at incoming packages of attack aircraft, or possibly as a killer of the E-3 Airborne Warning and Control System aircraft, large ISR platforms, or tankers.

China has acknowledged the existence of the J-20, but it hasn’t declared whether the aircraft is a concept demonstrator or operational prototype. US intelligence officials have testified before Congress that they believe the J-20 has been in the works since the mid-1990s.

China has forecast that the J-20 will reach initial operational capability in 2018.

The J-20’s first flight occurred in January 2011, coinciding with a visit to China by then-Defense Secretary Robert M. Gates. At the time, Gates said he believed his Chinese hosts were surprised by reports of the flight. Others saw the test as a deliberate snub of the American defense chief, who had forecast that a Chinese stealth fighter wouldn’t appear much before 2020.

Gates had used this argument in his successful 2009 push to cap production of the F-22 at 187 aircraft.

China’s J-31. The official September 2012 appearance of the Shenyang J-31 (sometimes called the J-21 or F-60) weirdly echoed the earlier debut of the J-20. The first photos of the aircraft in flight appeared on the Web shortly before Defense Secretary Leon E. Panetta visited China.

From another angle, the J-31 seems a ringer for the F-22. US officials hesitate to say espionage helped China design its new fighters, but the design similarities are many. (Photo via

Given the story of Gates and the J-20, it seems this might have been China’s way of sending the message that it has a vigorous aerospace enterprise with sufficient resources to develop two or more stealth designs simultaneously and that it intends to challenge the US in this arena.

Among non-American stealth aircraft, the J-31 most closely corresponds to the F-22 in shape. Moreover, the J-31’s apparent center of gravity suggests tremendous agility—another trademark of the F-22.

Indeed, a September 2011 photo of the Shenyang airplane on the Internet was dismissed as notional, mainly because it bore such a strong resemblance to the F-22.

However, viewed from the front, the J-31’s diverterless intakes strongly suggest an F-35 heritage. The initial frontal photos lacked sufficient resolution to show whether the engine fan blades are hidden within the fuselage, as they are on the F-22, F-35, and B-2.

Engine exhausts show little stealth shaping or stealth design considerations, though.

The landing gear of the aircraft is especially robust. The main gear resembles that of the US Navy’s legendary F-14 Tomcat, and the nose gear features double wheels. These elements, taken together, suggest a possible naval role and capacity for operations from an aircraft carrier.

Unlike US carrier aircraft, however, the J-31 doesn’t have readily apparent wing folds.

China’s Mystery Airplane. In summer 2012, the Internet was astir with several photos and videos showing an airframe being transported under a tarpaulin near Shenyang.

Pictures of China’s “mystery airplane,” shrouded in transport, began circulating in summer 2012. (Photo via Chinese Internet)

The image sparked robust debate among various armchair analysts and parlor Pershings, who mused about what the mystery aircraft could be.

One theory was that the aircraft was a durability test article of the J-31. Others who scrutinized the image said it had a shape more reminiscent of the F-35 than the F-22, meaning it was not a variant of the J-31 but rather something new.

It seems a good bet that Russia and China will follow through on stated plans to build hundreds of these putative fifth gen aircraft, as they have shown the technological capability to do so and have the hard currency to actually follow through.

Meanwhile, the Air Force will never have more than 185 F-22s. The production line has closed and restart costs are considered prohibitive.

Plans call for USAF to buy 1,763 F-35s, but that number seems likely to decline. In September, Secretary of the Air Force Michael B. Donley said the F-35 program will not be given any more money; therefore, additional “bills” will have to be met internally. That, he said, could lead to “reducing tails.”

Gen. Mark A. Welsh III, who took over as USAF Chief of Staff in August, knows the challenge will be a long and difficult one.

“The pursuit of fifth generation fighter technology by other countries,” he said in October, “is a reminder that we can’t rest in developing and fielding our own fifth gen fleet.”

The Sincerest Form of Flattery

Air Force leaders have been reluctant to say publicly that the similarities among the F-22, F-35, J-20, J-31, and T-50 are attributable to industrial theft and cyber espionage, especially in the case of China.

However, Maj. Gen. Christopher C. Bogdan, deputy F-35 program manager, said in September that the F-35’s Autonomic Logistics Information System, or ALIS, has severe security weaknesses and “vulnerabilities.” ALIS contains vast amounts of information on the construction of the aircraft and the status of every one of the Lightning IIs.

Bogdan’s remarks suggest the F-35 technology has probably been compromised. (He has been selected for promotion to lieutenant general and command of the program.) Now, he says, the weaknesses have been plugged.

While it seems that the J-20 and J-31 designs benefitted from work done on the F-22 and F-35, basic engineering also undoubtedly played a role.

The late Ben R. Rich, former head of Lockheed’s “Skunkworks” and the executive and engineer who oversaw development of the SR-71 Blackbird and F-117, frequently said pioneering aircraft often resemble each other because “the math is the same for everybody.” He pointed out that Lockheed’s nonselected entry for the B-2 bomber closely resembled Northrop’s winning design. That, he said, was because both companies were working from identical specifications for range, payload, and radar cross section.

China may have supercomputers equal to or better than those in the US—and probably some stolen information about the F-22 and F-35 that will allow it to skip wrong turns and dead ends encountered in the development of those aircraft. That means it may be able to bring its new fighters to initial service on the timeline it suggests, despite what former Chief of Staff Gen. Norton A. Schwartz described as the “struggles” to mature stealth technology.