Tuesday, March 11, 2014

Stealth Changes for China’s Stealth Fighter

When China unveiled its J-20 stealth fighter in 2011, analysts noted the aircraft’s potential to shift the regional balance of power further in the favor of the People’s Liberation Army Air Force. And the country is clearly committed to investing in military hardware. On Wednesday, China announced it was increasing its defense spending in 2014 to 808.23 billion renminbi, or about $132 billion, a rise of 12.2 percent. 
Sonic boom of J-20 Mighty Dragon
But many analysts have suggested that the J-20, ostensibly the showpiece of the air force’s modernization, had the “look” of being stealthy without actually incorporating many of the details that make aircraft difficult to detect on radar, as the defense journalist David Axe noted in The Diplomat in 2011.

For one thing, Mr. Axe wrote, “several rear-aspect photos seem to show traditional, fixed, round engine nozzles. The F-22, B-2 stealth bomber and now-retired F-117 stealth fighter-bomber all have carefully shaped, angular nozzles meant to scatter radar waves. In the F-22, these nozzles can move, ‘vectoring’ the engine thrust to boost maneuverability. The T-50 can pull the same vectoring trick with its round nozzles. The apparent absence of stealthy nozzles and thrust-vectoring places a hard limit on the J-20’s ability to evade radar detection from behind.”

The J-20’s nozzles are also mounted in such a way that infrared sensors could easily detect their heat signature. (The engines themselves pose a different type of engineering challenge for China, which may be more difficult to overcome.)

But the three aircraft seen so far are prototypes. Their manufacturer, Chengdu Aerospace Corporation, appears to be learning as it tests, based on photos circulating this week.

The first prototype, serial number 2001, shows significant differences from the latest prototype, serial number 2011, in the position and serration of the landing gear doors, the shapes of the nose and engine intakes (just to the rear of the cockpit) and the shape of the vertical stabilizers, or tail fins.

All those areas have been adjusted, presumably for performance and stealthiness reasons, as The Aviationist points out. The latest version also has a different paint scheme, which could mean absolutely nothing, but could also indicate a different type of radar-absorbent coating. The F-22, B-2 and F-35, the world’s only operational stealth aircraft, all use such coatings. 
The Chinese J-20 stealth fighter, in Chengdu, Sichuan Province, in 2011.
The J-20 made headlines when it was unveiled, not just because of the technology it represented, but because it came during Defense Secretary Robert M. Gates’s visit to China. At the time, Mr. Gates questioned “just how stealthy” the Chinese fighter really was, then said the Pentagon was stepping up investments in a range of weapons, jet fighters and technology in response to the J-20 and other aspects of the Chinese military buildup in the Pacific. A Pentagon spokesman later said that the J-20 “has not changed the strategic calculus at all.”

The Pentagon has since suggested that the J-20 will be ready for deployment no earlier than 2018, but it remains unclear how many of the planes China could field. China’s other stealthy aircraft prototype, the J-31, produced by Shenyang Aircraft, has been suggested as a potential export. So far the J-20 has, officially, only been earmarked for use by the Chinese military.

Meanwhile, it remains to be seen how much the J-20’s design changes matter and indeed how effective an aircraft it is. But it is evident that the plane’s flight testing, at least, is far more than just a publicity stunt.

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