Quote:
Originally posted by kach22i
I've oftened wonded why there is no ring or hoop connecting the blade tips of conventional fan and propellers. It seem to me that it would add strength. Perhaps the extra mass and the moment of energy would just be to great and offset any possible advantages.
My ideawould mostly be applied to ducted propellers and fans, to help narrow up the clearances and improve efficiency - by reducing blade tip vortices.
It seems this new propeller does that and more.
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In helicopters, they have addressed, as you correctly named (I did not), "blade tip vortices" with ducted tail rotors...sometimes called a finistron.
The interesting aspect to me is that finistrons are in line with the direction of the vehicle. The propeller in the link
is not. For every ring or hoop (shroud), there is an added drag coefficient that might impact the props benefits.
I wish I understood German!
Thanks again for the post.