nam wrote:In our case, we have the Su30 upgrade to try out the any large radar, that we want on AMCA.
I was wondering if SK wants to go with GaN based radar, explaining the lower TRM count. However I guess, lower TRM even with GaN might effect the number of beams that can be formed, there by effecting the tracking counts.
There is also the issue of the vivaldi antenna size, which may not allow compact TRMs. F35 antenna seems to be different and more compact than vivaldi.
The decision b/w GaA or GaN shouldn't have any impact on what size radar you should be able to accommodate. What is driving your design trades is going to be the overall aircraft design, internal RCS targets (this impacts how much sensors have to hold the advantage) cost, SWaP, threats (among other things) and their sensor suites. South Korea of late has bought fighters with fairly substantial radars. Their F-15's currently lack an AESA but the upgrade will give them a 1500+ module radar eventually, and their F-35A's have a 1676 module antenna. The KFX seems to have been sized closer to the F-16/F-18 level than contemporary 5th gen fighters. How large a radar you can accommodate is usually locked into the basic design and is always something you build around when it comes time to upgrade the sensor (as opposed to re-designing the base design to support a given future radar) which means its difficult to retrofit.
Looking through the documents that their design team has published (they've published a few papers on their initial testing of the first prototype of the radar), I don't see much around mostly electric architecture work or even test beds to de-risk this aspect ahead of the KFX. They are either doing it and not writing about it or they haven't invested a lot upfront and part of the KFX roadmap will invest into this over time. I suspect that, combined with their engine choice (no 5th gen engine with the higher power capacity) is probably why they've been conservative with this though I don't think it is the right way to go - You're not a true 5th gen IMO if you can't generate 2-3 x the electrical output relative to the aircraft you are replacing. Same for an increased thermal margin than the aircraft you are replacing (this is important for both subsystems and signature). They are fielding a Super Hornet engine with a roughly Super Hornet sized radar. I don't know if they are going aggressive in terms of EHAS implementation etc but they haven't published a lot on what electrical architecture or margins they are using on the KFX and there is certainly not been published work in terms of de-risking for the same.
the later iterations do look quite stealthy , but then you would know better
Yes for sure. They have iterations on their roadmap that will have an IWB, more RCS enhancements etc. But those aren't retrofittable to the initial aircraft fielded in the next 10 or so years. So those will be at a disadvantage just like they'll be at a performance disadvantage because of the design and external weapons (designed to have an IWB but has no IWB thus you get the higher drag and perf. degradation but no advantage). So some of this could have been mitigated by just giving them higher sensor performance. For a post 2030 IOC fighter, you aren't really competing with the MSA equipped fighters of the world (or that shouldn't be the goal)...the threats (I assume these are China and japan for S. Korea) would have mostly migrated to 1st or 2nd gen. AESA's for the most part.