Video by Japanese youtuber who filmed the best J-20 footage in 2016. Unfortunately, he didn't have a good spot this time and a guy's head got in the way of the view several times.
Of course they are not mockups. Yang Wei confirmed in an interview that they were combat units currently in service.
By screws or some sort, you can see them in this photo by @by78. Zoom in, you can see darker dots at the edge of the cover.Yeah, that's what I've gradually come around to thinking as well.
I do wonder what the purpose of covers are for, and how they manage to secure it over the EOIRST in flight. The pictures don't really seem to show any position for screws or attachment points
I counted 3 on all sides, 1 on the front tip. The total number are less than the rivets on the uncovered EOTS on the yellow bird (latest photo) few months ago. This is to say that the difference is due to the fixture of a cover.
@Bltizo, continue of #3774, as of the purpose, my guess is that the cover is to protect the window from scratch by solid particles in the air. At -70 degrees Celsius (12000m), water ice hardness is 6 on Mohs scale, that is harder than ordinary glass (5.5). You can see the long term effect on the window of air-liner. Although it will take a long time (years perhaps) for the mini scratches begin to affect the optical quality of the window, still why not use a cheap cover to prolong the life of more expensive window glass? Especially there is a big work of replacing the window glasses involving taking off the fuselage skin.
It certainly will. I think when PLAF begin to train and exercise with J-20 regularly and frequently, we will (if we can) see J-20 more often without the cover. Even then, PLAF may choose to use part of their aircrafts for training with EOTS mission, others for BVR training without the need for EOTS, thereby lower the overall cost of the fleet (waring a few than all). That would be my choice.For faceted fixed EOIRSTs like that of J-20 and F-35 they don't really have the option. Given that, I suppose it does make sense to cover up J-20's EOIRST when certain missions or flights have no need for it to help prolong the life of its housing a bit longer, though I can't help but wonder whether repeated removal and re attachment of the EOIRST cover may cause a bit of wear and tear at the screws/attachment points for the cover.