The Westland Scout is fitted with a Rolls Royce Nimbus Mk105 free-turbine engine.
A quote from the Pilots notes:- "Under standard conditions the rate of descent will be approximately 2200 ft/min at 5000Ibs and will reduce to 1500 ft/min at light weight, due to the increased power contribution required to maintain 420 rpm. A high weight flight-idle autorotation is very representative of an engine-off autorotation."