Firstly I am sure you can cruise for as long as you like at the power /
collective setting that gives you the least side slip . I am guessing around 60
knots straight and level with low torque .
Secondly I have done simulated
failures with what we considered to be neutral pedals ( lifting both feet off
doesn't work as the blades naturally throw some pitch on so you have to push
some opposite in )
If you do a shallow approach with wind off the R H side
you can get right down to 20 kn or less before touch down . You can either grab
for throttle ( 6 inch gap from collective ) or you could get the pax to pull it
back when you say pull !!! This is all on BA so same for all 350 s except B3
and Mil .
Loss of drive is not fixed pitch neutral. The fact it is spinning at a high rpm keeps it aerodynamically active. LTE would be a closer approximation.
SAS, I do not have first person experience but have been told that a 350 was relatively flyable w/o t/r drive. As well, a friend of mine had a net take his out and landed in a cut block w/o additional damage.
From a theory perspective, on every sim session I attend, someone asks if continued flight is possible w/o t/r drive and invariably the technician explain that no manufacturer has data on it and they make a series of assumptions to program the model. Not something that can be simulated in a real a/c unless you are willing to put a hand grenade in the tail boom.