The fuel flow is about half with the prop feathered.
To bad we can't do that with fan blades
. Not only potential fuel savings, but we get lots of complaints that the airplane taxis too fast at idle thrust and they need to ride the brakes.
BTW, yes, variable pitch fan blades have been looked at. At least so far, the cost, weight, complexity, and failure modes have made it less than desirable. Plus, to make it really worthwhile would require variable area fan nozzles
