[Public-List] Rudder Shape

Michael via Public-List public-list at lists.alberg30.org
Tue Feb 21 04:37:50 PST 2017

I always think of Kamm back cars of the late '70's on this subject. Kamm 
was an aerodynamic scientist who calculated the drag of building in a 
tear drop shape was more than just cutting off the back of the car 
square. Made for a bunch of ugly little cars.

Michael Grosh

------ Original Message ------
From: "Gordon Laco via Public-List" <public-list at lists.alberg30.org>
To: "Greg Roberts" <greg at midnight-oil.us>; "Alberg 30 Public List -- 
open to all" <public-list at lists.alberg30.org>
Sent: 2/21/2017 3:27:50 AM
Subject: Re: [Public-List] Rudder Shape

>Good day Greg,
>A foil shaped rudder would do you no good at all… one must consider, 
>with our sorts of boats, that the ‘foil’ has it’s leading edge at the 
>forward part of the keel and the rudder is a sort of flap or trim tab 
>on that structure, not something on it’s own.
>The only improvements one could give our rudders would be to minimize 
>the ‘leaking’ of flow from the leeward side to the windward between the 
>rudder post and the after part of the keel (already a pretty good fit 
>in Alberg 30’s except of course for the troublesome propeller aperture) 
>and perhaps a narrower and more squared trailing edge.   The thicker 
>rounded trailing edge (when considered in cross section) is not so good 
>for minimizing turbulence at the trailing edge.
>Gord #426 Surprise
>On 2017-02-21, 12:32 AM, "Public-List on behalf of Greg Roberts via 
>Public-List" <public-list-bounces at lists.alberg30.org on behalf of 
>public-list at lists.alberg30.org> wrote:
>     Did any of our boats come with a foil shaped rudder?My wood rudder 
>     flat sides and a gentle taper..I'm not sure how much one would gain
>     with a foil given the 3/4 keel,I'm having a hard time picturing how
>     you would handle the tilt when defining the profile.
>     Regards,
>     Greg
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