[whiskey111]

How can I change the default skin (in campaign) for AI aircraft ?

[KG64_Cnopicilin]

Open the mission in FMB and assign the skin for each aircraft separately. Other way is to go to the paintschemes folder and to the plane's skin folder and then rename the skins. If in the campaign they use default skin and you want to use Sk1nH4xors_yak1, then rename the Sk1nH4xors_yak1 to default.

[Nadia]

First, each time you put a skin on an airplane, IL2 creates a default-like skin in a paint-scheme folder called cache

The problem is to see or find that skin if you close Il2 normally, it erase all content of cache.
This can also take a while after a long game.
Three options to see in cache content:

crash the game. not a good advise.
change a setting in conf.ini [game] section, at the end: ClearCache=1 to ClearCache=0; must return it to normal 1 afterward or else.
Use the special computer key, the one that usually looks like "Windows flag" and put the game in the task-bar, then access file.
Copy you're new default where desired.

[Vpmedia]

in a dgen campaign?

[whiskey111]

Yes Vpmedia, in dgen campaign
Unfortunetelly KG64_Cnopicilin, your solution doesn't work. Any ideas ?
(I use HSFX)

[Vpmedia]

you need to edit the *.DB files in the Dgen folder

for example:

C:\Program Files\Ubisoft\IL-2 Sturmovik 1946\DGen\Africa40.db

...
[Planes]
34 CR_42 insert *.bmp here
4 JU_52_3MG4E vp_desert_campaign.bmp
2 C_47
4 BLENHEIM4 blenheim_Singapore.bmp
18 GLADIATOR1 Spain1.bmp
10 GLADIATOR2 Spain1.bmp
1 U_2VS U2trop.bmp
[Skill]
...

if winter available in that campaign (Stalingrad for example) you can add to bmp's

2 C_47 summer.bmp winter.bmp

[whiskey111]

I found a mod calls "skinmod". It works.
Thanks for your help