Foster Price wrote: > > >Allowing the prop to freewheel will reduce drag, but I'd > > be interested to know if the savings is significant or not > I'm not sure if hydrodynamic drag is the same as aerodynamic, but a freewheeling prop on an aircraft has drag equivalent to a disc the size of the prop arc! A critical step to dealing with engine failure in a multi-engine aircraft is to feather the prop to avoid unacceptable drag.