57es revision #5, helicopter rotor .

Wing one of five, with detail views of tip .

External surface .

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This correction to revision #4, (posted 9 August 2010), addresses an oversight which had applied code, (for the trailing edge taper),

which had not been modified to adapt it to the wings' narrower near-hub dimensions ; (compared to those of revision #2, posted 29 July 2010) .

This made no difference at the tip, but had left the trailing edges progressively lighter than intended as wings approached the hub .

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In all other respects, this revision is identical in form to revision #4 .

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A change applied (but not mentioned) in #4, and continued here, is the use of a somewhat larger foundation constant in code for generating the serration .

The effect on the wing's shape is to make the upper, (leading edge), teeth more triangular by shortening them, (very slightly), and adding material to their incurves ;

and, to make the lower, (trailing edge), teeth shallower by shortening them and adding material to their incurves also .

This makes the wing somewhat narrower overall ; resulting in a more compact, slightly less serrated form .

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Light gray arcs in four of the figures represent areas, (2, 4, 6, 8, 10, and 12) times pi over five, where i expect turbulence from other wings,

(and from the previous rotation of the same wing), would be encountered in a smooth-edged model .

The wings' serration is meant to handle this turbulence ; but the methodology is a carryover from wind turbine design, which is situationally simpler than that of rotors .

The spacing of the teeth may not be optimal for forward motion ;

and/or for a higher downwash velocity as one moves out along the radius of the wing .