I think this quote from a Marine F-35B pilot regarding an exercise pretty well says it all:
"I was leading a four ship of F-35s on a strike against 4th Gen adversaries, F-16s and F/A-18s. We fought our way in, we mapped the target, found the target, dropped JDAMs on the target and turned around and fought our way out. All the targets got hit, nobody got detected, and all the adversaries died. I thought, yes, this works, very, very, very well. Never detected, nobody had any idea we were out there."
The F-35B in particular is an amazing piece of engineering, and a vast improvement over any other STOVL aircraft.
From the Wikipedia article on the J-20:
"In October 2017, Chinese state media reported that the designs of J-20 had been finalized, and is ready for mass production as well as combat-ready."
"As of March 2017 there are still a series of technical problems that need to be tackled, including the reliability of its WS-15 engines, [the aircraft's flight] control system, stealth coatings and hull materials, and infrared sensor."
The Russian Su-57 is equally questionable:
"In December 2014, the Russian Air Force planned to receive 55 fighters by 2020. Yuri Borisov, Russia's deputy minister of defence for armaments stated in 2015 that the Air Force would slow production and reduce its initial order to 12 fighters and retain large fleets of fourth-generation fighters due to the nation's economy."
Both China and Russia are almost entirely dependent on their 4th Gen fighters at this point, and I expect the F-22 and F-35 will easily handle the J-20 if necessary. Regardless, 99.99% of potential adversaries are 4th Gen.
"At least six J-20s are in active service, with tail numbers 78271-78276 identified. Another six were believed ready to be delivered by end of Dec 2016. On 9 March 2017, Chinese officials confirmed that the J-20 had entered service in the Chinese air force.
In September 2017, the J-20 officially entered military service with PLAAF, making China the second country in the world after United States wielding fifth-generation stealth aircraft, and the first in Asia.
In January 2018, Chinese media reports that J-20 is in full operation-ready deployment."
"in two years’ time, if not before, America is likely to lose its monopoly of radar-beating stealth combat aircraft with the introduction into service of China’s Chengdu J-20. This has a much longer range than America’s new F-35 fighter and will be a serious threat to American warships in the Pacific."
"Another system, yet to be named, would provide China with an ability to knock out targets as far away as 400km, a far greater range than any other air-to-air weapon in service. It would threaten aircraft that currently operate safely from a considerable distance, such as tankers and planes used for airborne surveillance and control. "
In January 2018, Chinese media reports that J-20 is in full operation-ready deployment.'
Yeah, that all sounds great as propaganda. It's clear to any knowledgeable observer that the J-20 likely still has significant issues. As I mentioned before, it's also not at all clear how stealthy it is as well. There's a reason no other stealth aircraft has canards...
Carrier based F-35s will be in service soon (or already are in the case of the F-35B), countering the range advantage. All that said, the F-22 is the true counterpart to the J-20 and will likely mop the floor with it if necessary.
It's worth noting that for strike aircraft like the F-35, the main goal is avoiding detection to bomb targets. Stealth aircraft have no advantage over any other aircraft at detecting other stealth aircraft - making the J-20 no more of a threat than any Gen 4 aircraft.
Yep, that's interesting. I wonder how our jammers, anti-missile missiles, and directed energy weapons will fare against it...
This will handle Air combat quite fine.
"The short-range PL-10, which was introduced in 2015, is regarded by military analysts as comparable in performance to Western equivalents, such as the Sidewinder II. This year, the PL-15, a radar-guided “beyond visual range” missile (BVRAAM), should enter service. Carried by a J-20, the PL-15 can destroy an aircraft 50km away that is trying to evade it. “The Military Balance” believes that a version of the missile is in the works that will have a cruise speed of Mach 3. It is similar in design to the European Meteor, the best BVRAAM in the West’s inventory, which is only just entering service."
As you say J-20 will be used to deter aircraft carriers and warships.
"A 2015 RAND report noted the J-20’s “combination of forward stealth and long range could hold U.S. Navy surface assets at risk, and that a long-range maritime strike capability may be a cause for greater concern than a short-range air-superiority fighter like the F-22.” The J-20’s size and weapons configuration may, however, preclude it from functioning as an effective strike fighter in either context. Importantly, the mission types Chinese pilots are trained for may determine how the J-20 is eventually utilized."
"The U.S. Naval War College suggests that the J-20 could be an “effective surface-attack platform for out to several hundred nautical miles at sea.” Air Power Australia notes that the J-20 would be a suitable choice of aircraft for operating within China’s “first island chain” and “second island chain.” Should China integrate aerial refueling aircraft with the J-20, the stealth fighter’s operational range would extend even further across the Asia-Pacific."
Also note China is expected to deploy hypersonic weapons that are excellent for first strikes against naval forces.
Pardon me for my ignorance, why is that important? (My impression was "4th Gen adversaries" characterizes most, if not all, of the F-35's present adversaries.)