Yes
Compatible with 8.1
Install outside of the default Program folder/s
Just create a folder call it IL2 1946 or what ever you like and install to there.
If you cannot change the file path on installation
make the default install then copy and paste the contents to the new folder you made.
This is necessary due to file protection
IE: C:\IL2 1946 v4.12.2
Check this link out.
http://forum.1cpublishing.eu/showthread.php?t=40218