On Tue, 1 Jan 2008 08:45:32 -0800 Jim Cathey <[EMAIL PROTECTED]> wrote:
> > cloth over foam wings. I'm thinking I want to keep the speed under > > 800fps > > to avoid supersonic airflow, but 600-700fps might be better in > > practice. > > With a 60 foot circumference, you could do ten rps (600 rpm) and still > > have only a 600fps wing speed. > > Aren't these bird choppers? I thought modern ones were all > heading towards larger, slower mills. Indeed, larger, slower windmills will give the birds more time to get out of the way, but a private individual can only make smaller mills, so ... The Savonius turbines do have the advantage of a vertical axis and its consequent omnidirectionality, but they have the disadvantage of curved blades. I have some information (someplace around here ...) on a different type of vertical axis windmill, where the top of the vertical shaft has a horizontal crosspiece. At the ends of the crosspiece are the straight, vertical blades. The blades are attached to the crosspiece with hinges, which are attached to the blades just above the blades' middles. At higher RPMs, the centrifugal forces cause the blades to tilt, bottom out, and thus reduce their cross-section to the wind, thus governing the turbine. Looks like an interesting way to build one. Craig _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
