As of #1 I'm not sure about that one. What I explained is based on how radars work in general, so it's basicly more realistic, but not exactly how it should. Probably better option for now is to allow target switching but in scan mode instead of track mode.
However, I've just found something on RP-22 operations,
but it's in Polish so I'll have to translate it first. It explains things nicely, and much of this probably can be applied to RP-21 as well.
I'll translate it to english and send you.
BTW, I've spotted a bug
Helmet visor doesn't work on SM-12 for some reason - you can switch it with ctrl-d but it doesn't change anything - in outside view it's always lowered and in cockpit view it's never lowered (unless I'm blind and it's always lowered in pit view as well but it's still bugged).
EDIT: Derp, I just found it in english as well:
http://www.flyshark.republika.pl/Stacja_angielska/sapfir.htmIf I were to guess what to ditch to make RP-21 of that is: LAZUR, warning lights (launch authorized, seekeer ready, breakaway) because RP-21 besides M version wasn't integrated with missile systems (intended to use with heat seeking atolls) and it physically doesn't have any warning lights, and possibly IFF, though I think they already did have some form of IFF than.
Also here
http://en.wikipedia.org/wiki/RP-21_Sapfir (heil wiki) I found that vertical limit for RP-21 is as low as +/- 20* (60* is horizontal) and it's still 20* even in track mode, bc it's a hardware limitation - radar's had can't move further. So, if target went beyond 20* vertical range in track mode, it would be lost. Also basing on info in that link above, in scan mode limit is even lower.
Anyway, it seems that those 2 horizontal paddles you can move in scan mode are used for choosing target to lock on (it locked onto whatever was inbetween those lines). So one basicly had to adjust heading towards target (so it was inbetween the solid vertical lines) and than move the horizontal marker to select target from those in heading limit. Of course one could fit a whole squadron into that box, so I guess it would lock on to the target that was closest to the center of "highlited" target gate formed by horizontal, paddles and fixed vertical lines (or random one - that's an old radar after old, it has its limitations
). Once you switch to tracking mode it would simply follow (but this time in real time) the target chosen in scan mode as explained above. Seems pretty similar to how russian radars work today (at least in DCS
) but in modern ones the target gate is smaller and can be moved horizontally as well, so it's easier to select the target you want. Actually US radars in <insert random flightsim here> work pretty similar (so it should work for F-18), of course marking is differnt in each radar system, but there is still that target gate everywhere that you select the target you want to lock on with.