The slap sound should only be audible above certain bank angles and/or at certain descent rates. If it operates like the FSX edition, a helo static on the ground or in level flight won't generate the blade slap.
Version 1 way back in 2012 operated under the following parameters (thanks to an old post at FSDeveloper):
1. Below 40 kts with high bank angles (slap-volume depending on bank angle)
2. Descending between 110 / 45 kts (slap-volume depending on descend-rate)
3. At speed > 125 kts with pitch to forward
Can you double check your installation paths and then try to listen with some heavy maneuvering as outlined above?