1/ Not for this Project but later for AIM-7M and AIM-120A for F-18
2/ I don't know, you tell me. AFAIK no one is complaining about the switch target thingy . And I think in F-18 radar you can switch between different targets no problem. Additionally, yes you will lose your current target if you get out of tracking zone +/- 60 degree horizontal and vertical angle, 7000m - weather factor distance. you'll need to reacquire the target by getting it into the tracking zone. By losing its target, radar will automatically switch to another target. If you want I can code that radar will automatically turn back to scanning mode if no aircraft is currently in the tracking zone.
Well I don't think even F-18 radar can change tracking target without scanning again (though the only personal experience I can possibly have is another flight sims of course, like DCS) - that simply isn't logical, what I described is based on how modern radars work, RP-21 can't be OP relative to them. F-18 radar, if it's simillar or better than F-15 radar (I have no idea which particular system Hornet uses, TBH) can probably track multiple targets at once (all selected in scan mode), indeed, but it can't start tracking the target it didn't track before without scanning first because
it doesn't know it's there. Same when it looses target - it doesn't know where it is anymore when it stops tracking it and only way to find it is through scan mode.
I don't suggest auto switch to scan mode (especially that Rp-21 probably couldn't do it automatically, it would just show empty screen until pilot switches back manually) - the point it that switching between tagets in tracking mode (unless it tracks multiple objects like F-15, but only switching between tracked objects would be possible) or reaqcuiring them after they're lost, especially in old radar systems, is physically impossible - in scan mode radar's head moves and sends radar waves into the entire scanning area and registers all reflections - it can see all the targets in front of it, but none of them is tracked in real time, they're positions are refreshed at fixed rate and they can't be locked on with beam-riding missiles.
And here is where tracking mode jumps into action - in this mode radar points at single target selected in scan mode - and here is where target switching should be possible, in scan mode, you highlight the target you want to track and switch to track mode (i.e. lock on) I don't know if RP-21 allowed for selecting target in scan mode, or simply selected the one that would give clearest lock, but either of these would be more realistic. Once radar locks on the target and starts to track it, it sends radar waves
only there, thus it dosn't even know other targets exist anymore and can't find it without scanning again. basicly nothing is possible in track mode besides going back to scan mode. And yes, I have never flown the real one but this is how it's modelled in each other flight sim and it seems pretty logical
I am not complaining, in fact it's pretty fun to have an OP radar, but it's the same level of fun as it was with old Twister's missiles - TBH I prefer the current Jet War ones, it's a simulator, realism is an important factor. The point is that currently the scan mode serves no purpose and you can fly in tracking mode only, bc radar magically detects unknown targets in this mode.
As of Alkali, they're uselss anyway
and Russians didn't use them at this point. Atolls were more effective and they currently work realistically. I wonder if AMT is gonna add R-3R (radar gudied atolls) to MiG-21 though - they required a modified version of radar (RP-21M) which basicly allowed them to more actively cooperate with radar to guide them into target currently tracked with radar (i don't think it changed anything in radar's handling) This wasn't needed for Alkali afaik, since they're beem riding missiles (passive) and they just follow whatever sends the most radar waves into them - and RP-21 did exactly that in track mode, it illuminated tracked target like a christmas tree making alkalis follow it (in MiG-17PF (with RP-2 radar) target had to be tracked manually...) though no doubt if launched in scan mode, while being locked on by enemy fighter on 12 o'clock, they would follow the enemy fighter's radar bc it beams such tasty radar waves on them
tl;dr - If target switching would be possible in scan mode and impossible once in track mode (where it should simply track whatever you marked in scan mode) and reacquiring the target would require finding it in scan mode again, it would be more realistic, more practical and more logical.
However i don't know if it wouldn't be better to remove target selection at all and make it lock on whatever is closest to the center of lock on zone (as shown in the picture at page #1) when you switch to tracking mode - it's and old radar system after all, it would loose the track of target very frequently (e.g. it should loose the target whenever it's too far below due to ground clutter, which is still there even in tracking mode, RP-21 was not look-down/shoot-down capable), so this way it would be more to do with the radar besides staring at it, and it would be more entertaining to use