What will happen if fifth-generation fighters of the Chinese Air Force and the US Air Force "meet" in the area of a military operation or patrol? This question only at first glance seems somewhat strange. But, by and large, it has relevance due to the fact that American aircraft carriers with an aircraft wing from the F-35B are frequent guests in the waters adjacent to the sea borders of China. Moreover, fifth-generation F-35 aircraft are at the disposal of the regional neighbors of the PRC - Japan and South Korea. Soon they can become the basis of the Singapore military fleet.
The likelihood of a “meeting" F-35 and J-20 during patrols increases. And given that in the United States and China they like to put the "stealth" characteristics of their fighters in the first place, then it is worth considering such a meeting from the point of view of which of them will be the first to find the enemy.
For the Chinese fighter J-20 at frequencies of about 10 GHz, the EPR (effective scattering area) in the bow is in the range of 0,01-0,1 sq.m. In China, it is claimed that such indicators were obtained during testing in the BEC (anechoic chamber). In this situation, we are talking about a radio frequency BEC - one where there is no radio wave reflection from the walls of an enclosed space.
For the American F-35, taking into account the same angle, the EPR is estimated in thousandths of a square meter.
An approximate schematic EPR diagram for F-35, where the circle of the minimum radius corresponds to the declared 0,001 sq.m.
However, this, as in the Chinese case, is the data presented by the local media. How things really are with the J-20 and F-35 EPRs is an open question. But based on the data that is publicly available, the stealth of an American fighter is still higher than the stealth parameters of the brainchild of the Chinese military aircraft industry. That is, the "American" has an advantage in detecting, and therefore in the primacy of the attack (if we consider just such an option of "meeting" opponents in the air).
That's just all these calculations are ineffective in the case of a real air battle. After all, a situation in which the J-20 and F-35 will go one on another "nose to nose" has an extremely low probability. Accordingly, the detection (non-detection) parameters do not even depend so much on the capabilities of the radars (although, of course, also on them), but on the angle at which fighters will turn out to be at one time or another. The thing is quite obvious.
In other words, a possible meeting between the American and Chinese “invisibles” is not even “about invisibility” as such, but about who of the pilots will be lucky in the “X-hour”. Unless, of course, ignore individual skill, as well as additional means of assistance in the form of environmental monitoring tools that are not related to the avionics of the fifth generation fighter itself.
It turns out that even in the case of a “meeting” of two stealth aircraft (and with a hypothetical need to take the fight), the stealth of the fighter can hardly be put in the first place. Much more important is maneuverability and armament, its speed characteristics and the mentioned skill of a military pilot. Even the banal number of flying hours can play a role more important than the one that was determined when applying the stealth coating. First of all, this coverage can be important for overcoming ground-based air defense lines, but when entering a potential air battle, its importance is clearly reduced.