Here is a bit more detailed comparison of the sections over a wider range:
http://www.rickwill.bigpondhosting.com/Bi-directional_LtoD_Compare.pdf
and
http://www.rickwill.bigpondhosting.com/Bi-directional_Polar_Compare.pdf
You would expect that a good asymmetrical section would outperform a good symmetrical section for situations where you want more lift one way. The normal working range of the rudders would be from Cl of 0 up to about 0.4. Remember these would be sized somewhere between a normal rudder and a keel/board in terms of lift capability.
Rick
--- In harryproa@yahoogroups.com.au, Rick Willoughby <rickwill@...> wrote:
>
> ben
> Thanks for pointing that out. I did not look at his series 2 because
> he said it had stability issues.
>
> It caused me to compare what he arrived at with the 07 series I
> used. I have the Javafoil comparison here:
> http://www.rickwill.bigpondhosting.com/Rudder_Compare.png
> The Javafoil result for his P30210 is not far removed from his Xfoil
> result. His shape is not far off what I started with and thought
> would be a good shape primarily aimed at limiting the Cp for good
> high speed performance. I have spent a few hours fiddling with the
> pressure distribution to generate a better section than the 07 series
> and could not better it. The main difference between the ts P-series
> and the 07 is the larger diameter on the nose/tail of the 07.
>
> You will see there is some instability with the 07 but not as bad as
> the ts P section. I am not sure how this instability would translate
> into feel when the required lift is low. It does highlight the merit
> of rigidly linking the rudders with a reversing linkage so any
> instability in the moment is balanced out directly through the
> linkage. On the wind 07 section rudders should have progressive
> feel similar to the NACA00##.
>
> Rick
> On 06/08/2010, at 1:26 AM, bjarthur123 wrote:
>
> > > I scanned through them and none are asymmetrical.
> >
> > this one looks asymmetrical to me:
> >
> > http://www.basiliscus.com/ProaSections/AppendixC/p30215.jpg
> >
> > am i missing something?
> >
> > ben
> >
> >
>
> Rick Willoughby
> rickwill@...
> 03 9796 2415
> 0419 104 821
>
