How to change mouse speed and acceleration?

[Les]

You can change it in your Config file.

Local Disk(C)/Users/You/My Documents/1C SoftClub/il-2 sturmovik cliffs of dover/conf

Look for this section in your Config and adjust the numbers down to reduce sensitivity-

[rts_mouse]
SensitivityX=0.25
SensitivityY=0.25
SensitivityZ=0.25
Invert=0
SwapButtons = 0

I have them set at 0.25 to slow down the mouse movement in-game, but my mouse also has a button that can increase it's sensitivity and so speed the responsiveness back to normal if required (for menu's etc.)