SARH missiles like AIM-7 and R-27 should launch one by one.If the 1st missile don't reach target,you may not fire the 2nd missile.
but AIM-120 or AIM-9 and R-73 can be launched many at same time.
The earth is a globe,so the land and sea surface is a globe-surface.when I fly above the sea 30 feet in game,I can receive the ship-radar that far from me 150km.
Suggest:Think for frame-rate in game,designers may build a pre-globe-surface by the altitudes and distance of radar/target.
To unlock the enemy aircraft's radar,I often use "beam radar".in game the angle is 90 degree,but in fact it is a area,for excample 80-100 degree.so the "beam radar" will more easy and clever.
sorry for my english.