Kengsley wrote:I think its unrealistic to expect the J20 to immediately transition to a trapeze launched LOAL missile during the Low rate production phase of the programme.
Honestly, it is not at all unrealistic. We are in 2018 and the J-20 is very much a 2020s fighter and not hamstrung with ATF legacy design trades that were sealed into the design for those aircraft back in the late 1980s. Much of the heavy S&T to support the F-22 was done more than 3 decades ago. The J-20 in contrast is a more modern product and it isn't like the rest of the world hasn't been fielding LOAL solutions or missiles with capable data-links and processors.
Kengsley wrote:[ Until just recently when the Aim 9X was integrated, the F22 had to keep its bay open and extend its Aim 9 via the trapeze launcher into the air stream and wait for a lock before launching the missile and closing its weapons bay.
That has absolutely nothing to do with the J-20. When the F-22 got the Aim-9X, was a function of when the USAF felt that it was best to slot that capability in to the upgrade path for that aircraft. If they wanted to, they could have had it as the threshold platform and had the combo in operational testing half a decade earlier.
The BlkII Sidewinder itself was moving along much slower than it could have simply because there wasn't an urgency to develop it given the capability of the block-1 and the large acquisition of missiles already happening. The time-frames are reflective of schedule and budgets more than anything because there was not a very significant existential threat undermining US Air Superiority to counter which they had to move really fast.
Getting back to the J-20, this should have been the design solution employed had the Chinese been reasonably confident on those fronts. It was very similar for the F-35, where the USAF was confident enough in its future in terms of missile performance convergence and requirements (ejection vs rail launch) to not demand rails on the F-35, and the same was the case for the only one program partner that briefly explored adding rails. They were and still are confident of where their missile capability is headed and did not burden the designers by asking for features that were less relevant for the future. In this case, and very much the case with the J-20, the aircraft are being fielded in an era where Data links on CCMs are becoming the norm, and sensor aids like DAS are purposefully designed to help aid in a BFM set up. Where things are, and where they are headed impact design trades considerably unlike the 1980s era where those who framed ATF requirements had less certainty in terms of where the missile capability would be 2-3 decades out into the future.
Not only did that launch method increase the Raptor's RCS substantially whilst waiting for the missile to acquire a lock, but the open side bay disturbed the airflow around the jet during crucial WVR combat manoeuvring
RCS in a BFM? Are you serious?
Open bay doors only come into the equation if you are having to hold the missile on the rails for a long time to acquire a lock. If you can reduce that time you are actually on par with or at an advantage compared to an aircraft that must first execute the bay open procedures, swing out the missile with its mechanism, close the bay doors, acquire the target, launch the missile, open the bay doors again, retract the swing arms and then close the bay door again.
^ There you execute the open and close mechanism twice for every one shot. With a rail launched LOAL weapon on the F-22A you are doing it just once and the bay door is open for a very small amount of time as you don't need to acquire the target before launch. The swing arms while reducing airflow distortions still will not completely eliminate them. Of course the RCS point can be completely ignored..Once you are in a furball no one cares what your RCS is because your enemy can literally see you with his eyes/HMS/Missile seeker.
Kengsley wrote:[That's a significantly more complicated and costly(performance wise) system than the simple, low weight solution employed by the J20.
As I said, designers solved that by simply developing the Aim-9X II and with sensor-enhancements very much back on the F-22 i wouldn't be surprised if the AN/AAR-56 is up for some serious upgrade in the next couple of years allowing it to come in BFM targeting. I'm sure the next step for the USAF would be to just simply have eject launch requirements from one of the three A2A missile programs the service is working on. That will completely get rid of the rails business on the F-22.
Keep in mind that the YF-22 first fired a weapon from its bays more than 27 years ago. The J-20 on the other hand is still in the iterative phase of its development and as per Chinese claims, PR, cartoons, behind the shrubbery pictures, enhancements are still happening and being planned. One doesn't really need to be very good at reading between the lines to see what possible reasons could there be for a 2020's targeted maturity fighter to still incorporate this approach.
Point is that all the fancy annotations showing IR cameras that are supposed to be somehow analogous to the F-35 DAS even though they are first gen systems can't do much if your missile has to physically lock on before launch. You are then restricted to the frontal arc on each side of the missile bay where the seeker can actually see the target to establish a lock. Nose pointing still has to happen to get the seeker to see the target. You are still limited in terms of options you have in a defensive situation vs another fighter that has the ability to use its CCM with freedom and via cooperative targeting or LOAL using onboard sensors, launch the missile without the restriction of the target being in the seeker window fov of the missile.
Without LOAL, and even with an HMS system you are still restricted because the 2 CCMs on board individually do not have an unrestricted fov to match that of the pilot.