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Old 06-17-2017, 12:58 PM   #31 (permalink)
aerohead
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Quote:
Originally Posted by kach22i View Post
Bumping this old thread, can we call this trickle down technology or just marketing?


https://www.ruppams.com/CatalogConte...VLS/HVLSRA.asp
*they might defend their claims with more science.
*it's a fixed-pitch fan,fixed angle of attack,non-tapered,non-twist blade design.
There shouldn't be any 'surprises'.
*I suspect that it's a sub-critical Reynolds number blade,all in laminar flow.
*blades don't stall at the tip.They stall over the aft-body portion of the blade on top.
*Whales and raptors actively morph their fins and wings as well as alter their entire body's angle-of-attack.The fan blades are 'static.'
* I think the acoustic argument is okay.Owls are virtually 'silent' fliers,using feather down and feather serrations to mitigate otherwise noise-generating vorticity as an evolutionary strategy.They can hear their prey,but their prey never hear them coming.

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