The Chengdu Aircraft Company (CAC) J-20 5th generation stealth fighter made its first flight on 11th of January, 2011. Since then, the aircraft had come under immense scrutiny by Chinese military watchers, general military watchers, defence media, and general media. The existence or non-existence of a gun has been one of the aircraft’s many characteristics which have come into question.
As an air to air fighter, the J-20 would be expected to carry an onboard gun for last ditch self defence, and of the many types of fighter aircraft in the world, the vast majority carry an internal gun. Exceptions of the rule do exist, such as dedicated electronic warfare aircraft like the EA-18G which lacks an internal gun, and the F-35B and F-35C variants of the Joint Strike Fighter which both also lack an internal gun but have the provision to carry an external gun pod.
However, virtually no air to air fighters today and in the recent past exist without an internal gun, and even among general fighter aircraft it is a rare exception for an aircraft to lack an internal gun.
Reasons for doubt:
Some of the controversy surrounding the J-20’s gun armament status could be boiled down to two reasons.
-Lack of visual identification of a gunport on J-20
-Lack of any “official” confirmation or acknowledgement of a gun on J-20
Needless to say, the lack of an “official” acknowledgement of a gun on J-20 by Chinese military or government sources is not unexpected, given the overall state of Chinese military operational security. Therefore it may be unreasonable to use the lack of “official” acknowledgement of a gun as a basis for questioning its presence, because so much more about the aircraft is also unknown. At this stage even the official length of the aircraft is not known, let alone its armament, or sensor suite or anything else.
Virtually all of the conclusions about J-20’s subsystems and characteristics have emerged from eagle eyed Chinese military watchers using open source pictures and information to reach conclusions. Fortunately, recent pictures taken of J-20 have been of higher quality and have also shown a greater variety of the aircraft’s surfaces, allowing for more thorough examination of potential gunports.
Prior to considering the exact location of J-20’s gun, one must first consider whether it is located on the dorsal or ventral side of the aircraft. Aircraft like the Su-27, Mig-29, F-22, and F-16 feature gunports on the dorsal side, while other aircraft such as the Gripen, J-10, JH-7, place a gunport on the ventral side. Some aircraft such as the F-15 and Eurofighter Typhoon also equip their gunport at the wing root, and the F-18 family equips its gunport well inside the nose.
In the case of J-20, it becomes immediately obvious that it would be difficult for a gunport to be located on the ventral side of the aircraft, given the virtually completely smooth nature of the ventral fuselage, and the necessary presence of the main weapons bay which would obstruct the line of fire of any gunport.
It is equally unlikely for J-20 to fit a gunport in its nose, due to the likely lack of space in the nose due to the fitting out of extensive avionics equipment.
It would similarly be impossible for J-20 to locate a gunport in or near its wing root, as such a position would have its line of fire obstructed by the action of the forward canards, and bullets fired a wing root position may pass dangerously close to the canards, if not outright damage the aircraft itself. Needless to say, such a configuration would have been imbecilic and likely not even considered by the aircraft’s designers.
Therefore, any gunport position would likely have to be on the dorsal side of the J-20, and it should also sit in a position where its line of fire is safe from any obstruction by the canards or any other part of the aircraft itself.
In other words, the location of a gunport would likely be quite similar in position to that of the F-22, or Su-27, Mig-29 or F-16. However, the lack of sufficiently detailed photos of the J-20’s dorsal side have not allowed for serious inspection of this possibility until recently.
The fact that J-20 is a stealth aircraft means its gunport may be very difficult to observe compared to non-stealthy aircraft. The F-35A and the current prototypes of the Russian T-50 both feature somewhat obvious, “bulging” gunports, however the F-22’s gunport is enclosed within a door which only opens to expose the gun during firing, and is all but smooth and indistinguishable compared to the aircraft’s dorsal fuselage when the door is closed. Given the careful attention paid by the CAC to the rest of the J-20’s geometry for preserving stealth, it would not be unlikely for the aircraft to have a very difficult to distinguish gunport as well.
Fortunately, higher quality pictures depicting J-20’s dorsal side emerged in mid 2015, and to the great joy of Chinese military watchers who have been following the J-20 gun saga, some of the pictures depicted a very distinctive set of panels on J-20’s port (left) and dorsal side, a few meters immediately posterior to the port air intake.
The position of those panels appeared perfect for a gunport to be located, as such a position would provide a clear line of fire well safe by the J-20’s canards, as well as provide sufficient volume for a gun and its supporting equipment (power source, ammunition canister) to be located despite being barely visible externally. Furthermore, the location of the panels on J-20 is also similar to the location of the F-22’s gun and gunport, only that it is located on the port side rather than the starboard side.
The geometry of the panels is also consistent with the size and configuration that would be expected for accommodating a gun. The larger, more posterior panel is rectangular in overall shape and aligned lengthwise with the axis of the aircraft, which would be consistent with the standard arrangement of a gun and supporting systems aboard a fighter aircraft. The smaller, more anterior panel is generally square in shape, and is consistent in relative position and size (compared to the rectangular panel to what would be expected for the door mechanism to expose the gun’s barrel during firing.
The lack of a similar set of panels on the starboard side of the aircraft further supports the notion that the panels on the port side are for a gunport, because virtually all modern fighters only have one single gunport alone, mounted in one position.
However, the suspected gunport does not provide any details as to just what type of gun the J-20 may field. Currently, two major guns equip the Chinese Air Force fighter fleet: the domestically produced version of the Russian, dual barrel 23mm GSh-23, or the domestically produced version of the Russian, single barrel 30mm GSh-30. Either gun could be suitable for J-20, or an entirely new design could grace the aircraft instead.
At present, the logical rationale supporting J-20 having a gunport, together with recent photographic evidence which likely depicts J-20’s gunport on the port/dorsal side of the fuselage, help to make a strong case for J-20 to have a gunport.
However, skeptics may remain unconvinced until pictures or video clearly display J-20’s gunport exposed and open, revealing the gun itself. Unfortunately, such resources may not be released by the Chinese Air Force for many years, and until then, skeptics will likely remain vocal in asserting the J-20’s lack of gun armament.