Blast radius collision are simply a sphere. And damage varies with the square of the distance.
Armored vehicles will take damaged just like being hit by a weapon in that if it doesn't penetrate, no damage is applied.
HiTech

Which one of the 3? If it is a true spherical blast (no1) then a good strategy would be to go low onto the deck right after an attack run? 2 would seem a strange shape for a blast, 3 seems a more likely blast for a shell fired into the ground?
And can you accumulate blast damage in a plane, ie a near miss on one will lead to a greater likelyhood of failure on the next pass?
There you go, pervert. Everything I said is now verified. You can now end the shreckless attack on vehicles in the game.
Ahem, I am trying to talk to someone who has actually made a flight sim...thats not you btw, fake sims don't count, go sit in the corner there like a good girl.