[Public-List] Rudder Shape

[Rod Symmes via Public-List]

What I remember from aerodynamics in that time period was that European car rally drivers prefered the Volvo station wagon over the sedan because,  in spite of the extra pounds of glass, they were 2 or 3 mph faster with that square back end.
Go figger ?


Cheers,  Rod

-------- Original message --------
From: Michael via Public-List
Date:21-02-2017 7:37 AM (GMT-05:00)
To: Gordon Laco , Greg Roberts , Alberg 30 Public List -- open to all
Subject: Re: [Public-List] Rudder Shape

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
#220

------ 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
>has
>     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
>     _______________________________________________
>     These businesses support your Association:
>     http://www.alberg30.org/store/A30supporters.html
>     Please support them.
>     _______________________________________________
>     Public-List mailing list
>     Public-List at lists.alberg30.org
>     http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org
>
>
>
>_______________________________________________
>These businesses support your Association:
>http://www.alberg30.org/store/A30supporters.html
>Please support them.
>_______________________________________________
>Public-List mailing list
>Public-List at lists.alberg30.org
>http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org

_______________________________________________
These businesses support your Association:
http://www.alberg30.org/store/A30supporters.html
Please support them.
_______________________________________________
Public-List mailing list
Public-List at lists.alberg30.org
http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org