How China's stealthy new J-20 fighter jet compares the the US's F-22 and F-35

Two Chengdu J-20 stealth fighters headlined China's Airshow China in Zhuhai Tuesday while only flying for only minutes, Reuters reports.

But Justin Bronk, a Research Fellow specializing in combat airpower at the Royal United Services Institute, said the display left many questions unanswered.

On paper, the J-20 represents a "big leap forward in terms of the capabilities of the PLA (People's Liberation Army) have on scene," said Bronk.

Compared to the US's current fifth-generation fighter jets, the F-22 and the F-35, the J-20 has "longer range, more internal fuel capacity, and larger internal weapons capability," said Bronk.

This combination of factors presents a real risk to US forces in the Pacific. Long range, capable strike fighters like the J-20 put US "AWACS [airborne warning and control system], refueling tankers, and forward bases at risk much more than current types if flying in relatively large numbers" should any kind of kinetic conflict flare up in the Pacific, said Bronk.

However, US Air Force Chief of Staff David Goldfein told Breaking Defense he was not overly troubled by the new Chinese jet.

"When I hear about F-35 vs. J-20, it's almost an irrelevant comparison," Goldfein said in August.

Indeed nothing indicates that the Chinese have built in the type of hyper connectivity and sensor fusions that make the US's fifth-generation fighters so groundbreaking. In the F-35 in particular, "pilots are not spending a huge amount of time managing inputs - the machine does it for him. It produces one unified picture which he can then interrogate as required," said Bronk.

This gives F-35 pilots a situational awareness that the Chinese likely leverage in combat.

But what exactly goes on under the hood of the J-20 remains an absolute mystery. What is known is that the Chinese have managed to steal a considerable amount of info from US defense aviation projects.

"We don't know how much F-35 technology the Chinese have managed to steal," said Bronk, adding that while it's "impossible to say for sure" what the J-20 is capable of, common sense dictates that the "the sensor fusion and network integration is significantly behind what the US has managed with the F-35 and F-22. This is purely based on the fact that sensor fusion has taken the most effort, time, and money."

But one-on-one combat scenarios or feature-for-feature comparisons don't capture the real threat of the J-20.

Long range stealth fighters, if fielded in large numbers along with older Chinese aircraft, surface-to-air missile batteries, radar outposts, missiles, and electronic warfare units present another wrinkle in an already complicated and fraught operating envelope for US and allied forces in the Pacific.

But is it real?

Whether the Chinese will actually be able to field this plane by 2018, as Beijing has projected, remains the real question.

Bronk pointed out that it took a decade between US developers building a flying model of the F-22 and getting real, capable F-22s in the air. Even if the Chinese have accelerated the process through espionage, Bronk says "We know how much money and time it takes to make a lethal and effective fighter like the F-22" and it's "very unlikely that China is that far along."

Additionally, the J-20s in Zhuhai only flew for about one minute. They didn't do low passes. They didn't open up the weapons bay. They didn't do much except fly around a single time.

"We learned very little. We learned it is very loud. But we can't tell what type of engine it has, or very much about the mobility," Greg Waldron, the Asia managing editor of FlightGlobal, told Reuters. 

Bronk speculates that the models on display at Airshow China were not much more than show pieces: "It's possible that the aircraft that were shown are still instrumented production aircraft," or planes with "loads of sensors to monitor performance" instead of in a combat-ready formation.

Bronk points out that the aircraft most likely flew with underpowered engines, and not the engines that would fly on the final version. "Engine performance is a key function of any aircraft. China and Russia continue to lag behind because of the really top end manufacturing processes you need" to create and tune high quality aircraft engines.

So while China's new "impressive low-observable heavy strike" fighters could change the balance of power in the Pacific, whether or not they can field the planes in significantly large numbers at any time in the near future remains an open question.

Watch footage of the J-20's flight below: