Now can this convention be broken? I'm not a tech genius or anything but as per my post #5704, I see the possibility of a retractable data plug and a jack on the missile replacing the wire. If you can plug a cellphone into a computer and they can communicate perfectly, what's stopping that happening between a missile and its fighter?
A couple of issues.
1) The connection has to deal with high g-forces. The last thing you want is missiles not able to launch because the data cable pulled loose when you were manoeuvring had to get the shot.
2) Mechanical complexity, volume and weight. While it is not impossible, or indeed even hard, to design a mechanism to plug in a standard missile hardline cable, screw it in and reset the launch rail guillotine; such a device would most likely weight a fair bit, have a fair bit of volume (especially if all the parts need to be able to tolerate high g-forces and extreme temperature and pressure variations), and be pretty complex. and I am not even considering cost.
All of that is not a great trade off to be able to load just one extra missile per bay/loading device.
Such a reloading device would only make sense if you have a magazine with many rounds to reload, but you would be looking at medium bomber size planes at the minimum in that case.
As I said before, the easiest, and only, way I can see them fitting a second missiles in the side bays is if they had a second rail attached to the inside of the weapon bay door.
That way you don’t need to add in any more moving parts than is already in the design.
The only issue I can maybe see with that approach is one of clearance, since if you had a missile hanging off the weapons bay door, you will need the doors to be able to swing far enough out that the other missile can also swing out without hitting it.
That may be the issue, as the J20’s side bays don’t seem to extend far enough out to allow the swivel rail to deploy out with a missile if there is also another missile already attached to the inside of the weapons bay door.
The most obvious solution to that problem would be to have a slide rail, so the second missile (and launch rail) is stored inside the side bay normally, and would only move down the slide rail, to rest attached to the inside of the side bay doors, when ready to be fired.
The slide rail would be a simple one-way system, deployed via a one-shot gas/pneumatic charge to save on weight/complexity.
If given enough internal volume and weight allowances, that’s how I could design in a second SRAAM for the side bays.