The much celebrated 66% efficiency of the 1903 propellers not confirmed by wind tunnel tests
Well these people disagree.
http://www.wrightexperience.com/indepth/pdfs/props.pdf
A pity you don't understand what is written in the references you yourself use, which says
These data show that the 1903 Wright propeller had a maximum efficiency of 82 percent.
Based on Wilbur Wright's notes on the fourth flight of Dec. 17, 1903, the Flyer had an estimated forward speed of 31 mph during the steady flight portion of its path and the propellers were turning at 379 rpm, which yields an advance ratio of 0.85. Hence, the 1903 Wright propellers were operating at a mechanical efficiency of slightly over 75 percent during steady flight.
I see you're giving it a thrashing here as well
http://www.pilotsofamerica.com/forum...ad.php?t=71304