DCS World beta is free to download.
the only flyable plane is the Su-25T.
i downloaded and installed the first 4 files on the following page. the files with DCS_World_en in their names.http://www.digitalcombatsimulator.com/in...135&lang=en
i don't want to buy the P-51 so i didn't download the fifth file named P-51D_220.127.116.11.exe
if you own them, the upcoming patches for A-10C and Black Shark 2 will integrate them into DCS World.
note the first item under "Features" on the following pages.
Upcoming A-10C Patch Change Log: http://forums.eagle.ru/showpost.php?p=1449362&postcount=1
Upcoming Black Shark 2 Patch Change Log: http://forums.eagle.ru/showpost.php?p=1449366&postcount=1