Assault approach on the Herc?
You can't put the props into Beta in the air on the Herc..in fact..if there isn't enough power being generated from the engine to keep the torque positive....the prop will 'decouple' from the engine if the NTS (negative torque system) doesn't correct it.
It's been years since I've done one...I believe that the assault approach was based on flap 50 stall speed...there has to be some other military guys out there that know...I can't remember the speeds!