Originally Posted by
Vessbot
A paper was just posted a few posts up describing the results of an experiment showing the opposite -- and it really seems the eggheads had done their work properly, it has Greek letters and everything!
That paper was talking about the internal drag on the engine only, as stated in the paper. As many here have pointed out, the drag on a propeller or on the fan itself is lower when the prop or fan is seized. However, in that condition the air flow through the inlet is significantly reduced, resulting in increased spillage from the inlet. My recollection from the discussions back when the reserve fuel requirements were being developed for ETOPS was that the overall nacelle drag was greater at single engine cruise speeds with the fan seized due to the effect of the spillage. However, enough of you are saying the opposite to make me question whether my memory is accurate. It was 30 years ago. I'll check some of the aircraft operation documentation I have when I'm back in the office on Tuesday and post what I find.