China has test-flown a second model of a prototype stealth fighter, aviation experts said. Photos posted online on Thursday showed the aircraft airborne with its landing gear down near the north-eastern city of Shenyang.
Two Chinese-made J-11 fighters accompanied it on the flight, which Chinese military enthusiast websites said took place on Wednesday and lasted about 10 minutes.
Ross Babbage, of Australia's Kokoda Foundation, and Greg Waldron, of Flightglobal magazine in Singapore, said the plane, known as the J-31, appeared to be a smaller version of the J-20 prototype that was tested last year in Chengdu.
Both planes feature stealth design features but their true capabilities in terms of sensors, radar-absorbing coatings and other factors remain unknown. It is not known when, or if, either plane will go into production.
"I think it's a fairly straightforward evolution to develop advanced fighters at this time, but you can't read too much into it in terms of capabilities," Waldron said. He said the smaller and nimbler J-31 appeared intended for a fighter-interceptor role similar to the US Joint Strike Fighter, and the heavier J-20 could target airfields, warships and other ground targets.
The technical barriers and development costs for such aircraft are enormous and the US has struggled for years to deliver on their potential. Babbage said another challenge for China was developing engines reliable and capable enough for such cutting-edge aircraft.
China remains overwhelmingly reliant on Russia for engines for its latest J-10, J-11, and J-15 models, the last two of which were developed from Russian Sukhoi fighter-bombers. "The demands in the engine area are very substantial," Babbage said.
Despite that, the ability to develop two prototype stealth fighters at the same time demonstrates an impressive capability on the part of the Chinese industry, he said. "It's a very interesting development. It shows how rapidly they're moving ahead."