Has anyone played with the spreadsheet at The Bootstrap Approach to Aircraft Performance<br>(Part Two Constant-Speed Propeller Airplanes) ? Looks like a good tool; the one thing that surprised me is how pessimistic it is about (constant speed) propeller efficiency, with the predicted maximum efficiency of a (two blade) Cessna 182 prop being under 74%. I was under the impression that numbers closer to 80% - 85% were somewhat common... and I notice there's no "fudge factor" for prop material. Any sense of what's actually realistic to design to?
