China improves J-31 stealth fighter with better engines, stealth and sensors

An improved J-31 stealth fighter prototype has increased test flights in April 2017. This stealth fighter could be used for Chinese aircraft carriers. China now has a refurbished Ukrainian aircraft carrier and a domestically produced aircraft carrier. Both carriers use older jump ramp technology instead powered launching systems.

The twin-engine J-31 is roughly the same size as the American F-35, with a range of 775 miles, a maximum takeoff weight of 28 tons, and a Mach 1.8 top speed.

The improved prototype first flew on December 26, 2016. The new J-31 prototype is three tons heavier and about 20 inches longer than the original technology demonstrator.

Key improvements are
* IRST sensor
* stealthier wings
* cleaner burning engines
* improved radar.

In addition to avionics and datalinks that enable sensor fusion, SAC officials state that the production J-31s (which could appear soon as 2019) could have supercruise capability, giving them a leg up over current F-35 fighters. Its WS-13 engines would be replaced by domestic WS-13E or WS-17 turbofan engines to give it that advantage in speed. The combination of the J-31’s high speed performance, and suggested payload of 6 PL-12 or 4 PL-21 long range air to air missiles suggests that the J-31 has been optimized as an air superiority fighter, though it can be fitted with a wide array of Chinese precision guided munitions like the LS smart bombs.

The new J-31 prototype (the one in lighter gray paint) is expected to be larger, have a nose-mounted infrared search and tracking sensor, and stealthy features like clipped horizontal and vertical stabilizers.
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According to a report, in 2012 China developed FWS-13 on the basis of Russian RD-93 to increase its thrust with augmentation to about 8,500 kg. The engine was successfully tested on a J-31, but the thrust is still not enough.

On April 22, 2016, Liyang’s holding company announced that it is investing 961 million yuan (US$171 million) in Liyang to build a production line of third-generation medium thrust aircraft engines including WS-13E with reduced weight and increased augmented thrust.

It says that the WS-13E weight will be reduced from 1,135 kg to 1,050 kg but its maximum augmented thrust will be increased from about 8,700 kg to more than 9,000 kg to raise its thrust-to-weight ratio to 8.8.