Sorry Wing, I can't figure out how to upload that zip, and besides that, in my notes I wrote where I saved this WAV file I also note that I got this WAV file from a downloaded plane found on Flightsim, so anyway I suppose it best I do not upload the WAV file even though I couldn't find a readme for the plane.
But I will tell you where you can locate, download the plane and copy the WAV file to use. Once you retrieve it and copy it some where you will have to rename it to warthog_cannon after renaming the original warthog_cannon WAV file that should be in your FS9\Sound folder.
I know it is a little work, but it is really an impressive replica sound of the Gau 8 A-10 cannon and it is loud.
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If you want to try it:
1. Search for, FS2004 Vampire Series, or file search, 3ships(dot)zip ,on Flightsim search page, and download it.
2. Unzip the plane to a nominal folder location, or you may even be able to copy just the WAV file out of the zip.
The WAV file you want is the xshutdown WAV file. (Once you locate it you should be able to click on it to listen to it)
3. You want to copy this single WAV sound file named xshutdown and place it somewhere and then re-name it to warthog_cannon and then place it into your FS9\Sound folder. If you want to keep that original warthog_cannon sound just rename it before you put the new sound in the FS9\Sound folder.
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It is interesting this WAV file was used as shutdown WAV file on that plane, it doesn't sound anything like a shutdown sound, but it is a very close match for the A-10's Gau 8 cannon. And I have searched long and wide looking for a good match for that specific peculiar sound, looking through lots of freeware download sounds of groans, fog horns, door creeks, and table and chair sounds dragged across the floor. Incidently the original one I used was a door creeking sound.
Hope you try it out and enjoy it.