Dennis, My limited understanding of aerodynamics is that if the foot is not on the dock then the higher pressure is allowed to "leak" under the foot to the low pressure side, diminishing lift. That's why they now have tips on airplane wings. If the cabin causes upward deflection, that may be more than offset by maintaining the pressure differential. But either way, you are +6 sec./mile!
Joel 35/3 Annapolis On Wed, May 7, 2014 at 8:51 AM, Dennis C. via CnC-List < cnc-list@cnc-list.com> wrote: > I recently re-filed my PHRF certificate to get +6 seconds for a roller > furler. Subsequently, I just had the luff my Mylar/Kevlar 155 cut down to > fit on the furler. My sailmaker cut a bunch off the foot. > > I was chatting about loosing the sail area with one of the really good > sailors in the club. He said it may actually be a good thing that the foot > is higher off the deck. He said with the older narrow IOR designs, deck > sweeper genoas may cause the slot to be less efficient. Might increase the > bubble in the main. > > In my simplistic mind I kinda see where he's coming from. The slot gets > restricted at the deck by the cabin. The lower part of the air flow would > get pushed upward into the bottom of the main. A higher foot allows some > flow to escape and keep the air flow lines smooth in the lower slot. > > Does this make sense? > > Dennis C. > Touché 35-1 #83 > MandevilleLA > > Sent from my iPhone > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > CnC-List@cnc-list.com > -- Joel 301 541 8551
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