I have another model - the FS9 one, ported over to CFS3. It needs a bit of tweaking, so I've just sent it to Ted.
Meanwhile, open the C-47 xdp and you'll see these lines (from the PTO version):
<DamageBoxes>
<Box ID="damagebox_nose" Parent="damagebox_fuselage">
<BoxMap SystemID="nose_structure" Probability="100" Points="93"></BoxMap>
</Box>
<Box ID="damagebox_fuselage" Parent="damagebox_fuselage">
<BoxMap SystemID="fuselage_structure" Probability="99" Points="11715"></BoxMap>
<BoxMap SystemID="hydraulics_reservoir" Probability="1" Points="34"></BoxMap>
</Box>
I've highlighted the interesting bit in red - basically, whenever a round hits this part of the aircraft, it deducts a number of points from the total. If the total is very high, you'll have to hit it very hard before the effects - including destruction - take place.
The lines above are for the fuselage. Now let's see the AvH B-25, as suggested above:
<DamageBoxes>
<Box ID="damagebox_fuselage" Parent="damagebox_fuselage">
<BoxMap SystemID="fuselage_structure" Probability="62" Points="1317"/>
<BoxMap SystemID="center_fuel_tank" Probability="16" Points="334"/>
<BoxMap SystemID="bomb_release" Probability="5" Points="96"/>
<BoxMap SystemID="bomb_bay" Probability="10" Points="200"/>
<BoxMap SystemID="hydraulics_reservoir" Probability="7" Points="153"/>
</Box>
Putting aside the component parts, you have in the C-47 a 99% probability of damaging the fuselage, and 11715 "strength" points. That's huge.
By contrast, if you hit the AvH B-25's fuselage, you have a 62% possibility of doing it noticeable harm, and a strength value of 1317 points. That's about par for the course.
In other words, the C-47 is not far off ten times as strong as it should be.
Look a bit further down, and you'll find this:
<System ID="fuselage_structure" Name="Fuselage Structure">
<Threshold Level="2" Effect="Library" Parameter="fx_fuelleak_m" Location="emitter_fueltank_center"></Threshold>
<Threshold Level="60" Effect="library" Parameter="fx_engfire_l" Location="emitter_damage_wing_root_right"></Threshold>
<Threshold Level="25" Effect="library" Parameter="fx_engfire_m" Location="emitter_fueltank_center"></Threshold>
<Threshold Level="10" Effect="Library" Parameter="fx_oilleak" Location="emitter_damage_wing_root_left"></Threshold>
<Threshold Level="100" Effect="Break" Parameter="" Location=""></Threshold>
</System>
That means that for 2% damage, you get fx_fuelleak_m, and for 60%, fx_engfire_l, and so on. But you'll see then that each effect is assigned to an emitter... If the emitters aren't there in the model, then there you are. As I said, some can be placed with X,Y,Z co-ordinates, but as I haven't done these things for ages, I'd rather someone else who is more knowledgeable finished off the story.