[Jaypack44]

C:/ Program Files/Ubisoft/Il2 Sturmovik 1946/
You may have to extract the file from the.sfs archives, and then create your own folder in the MODS folder with this structure:

MODS/(name of your folder)/3do/plane/(the folder of the plane that you want to change,e.g. F4U-1A(USA))/hier.him

Hope that helps!