OK.
All planes use same named .wavs. For instance, every plane's engine sound is called 'eng.wav'. If you do not use a custom sound pack then every plane you fly is using the default (HTC supplied) 'eng.wav'. Each plane will play this sound a bit differently so it will sound a little different in each. Custom sound packs can supply a variety of sounds by means of folders named for each airplane or gv. If you look in the sounds folder you should see a bunch of folders named as such (providing you are using a custom sound pack). If you look in each folder you will see a variety of .wavs. Every airplane folder will have its own 'eng.wav'. So if you wanted to replace an engine sound with a different one you will need to rename the current one to something else ( I do 'engO.wav) and then copy the new one into that folder.
Now, you want hit sounds replaced. The possible range of hit sounds are; hit.wav, hit_1.wav thru hit_7.wav (maybe there are more, don't know). Each of these hit sounds represent getting hit with different caliber rounds (there may be more criteria, also don't know, I wish they would publish a list explaining where and how every sound is used). You will need to rename sounds to match the above mentioned naming. In other words, if you want to try my sounds here is a hypothetical scenario;
1. download the .rar file from my site (you will need the program 'unrar' - available on the web for free)
2. create a folder and name it something like 'zes hit sounds'
3. locate the downloaded .rar file on your computer and right-click drag and drop it on the 'zes hit sounds' folder and select 'extract here'.
note - if you don't see 'extract here' in the context menu when letting go of the drag and drop then you don't have 'unrar' installed.
4. next, look in this folder and see that the files are named differently than mentioned above.
5. listen to the sounds and decide which you want to try.
6. rename the chosen sounds to one of the above (hit.wav or hit_5.wav, etc.)
7. open the Aces High II folder and find the folder called 'sounds'.
8. open the sounds folder and find the folder named for the plane or gv inwhich you want to hear the hit sounds when you are in that plane or gv.
9. copy the hit sounds that you renamed into the plane or gv folder.
10. done.
11. well probably not really. Since there are at least 8 different hit sounds AND I don't really know how they are assigned it is sometimes difficult to know how to name them. This is compounded by the fact that you (hopefully) don't hear hit sounds so often making it hard to tell if YOUR naming was good for the effect you are after. I deal with this by choosing 8 sounds and name them as mentioned. Put them all in a given folder and either go get hammered in the MA, TA, DA, whatever (and film it). If you don't like how a hit sound was assigned you need to remember what it sounded like, find it in the folder, and swap it with one that you would rather it sound like. If you film or find an .ahf film that has you getting hit and you know how you want it to sound then the swapping is easier.
Again, if there were a sound use list I could tell you exactly what is what....but alas.
Hope this helps.
zes