Well
iirc "hit boxes" are not used for aircraft DM.
Of course I will stand corrected but I'm sure a different method is used to damage the
actual parts.
Damage modelling explained in the link.
http://www.sas1946.com/main/index.php?topic=357.0
Damage
As explained in the general overview & parts & naming, an Il-2 aircraft is really a collection of parts flying in formation. There are three basic sets of parts, each corresponding to a "level" of damage. Levels are explained as follows:
D0 - No damage: This is the aircraft completely undamaged in normal running condition.
D1 - Light damage: Small holes from small or medium caliber machine guns and shrapnel.
D2 - Heavy damage is Light damage, plus large, threatening holes blown in the individual parts from cannon shells. Internal structure may well be visible, represented by D4 parts (see Caps & Internals page).
Note:
Perhaps some revisions may have taken place since the original post in later DT patches
I'm unsure but I would expect it to be untouched from the original concept.