Fatter (thicker) than 0012 is better. More useable lift and wider range of angle of attack. AS speer says a wing with flap is better than just a wing. Even better if you can add a foil over the leading edge as well. (just like a jib adds to main). Stay with symmetric wing shapes as camber inducement has been argueably difficult in a rigid shape.
Angle of attack for rigid wings is smaller than thin foil like a sail. Foil allows lift to shift from front to back depending on sail camber thus wider range for AOA. Sooo plan on a way to more easily manage angle of attack like a tail rudder.
Feathering allows sails (wings)to depower. BUT what no one talks about is wing is live 24/7. Even when feathered air flow is never laminar, gusts and eddies hit the wing at various angles at all times. The wing is creating lift nearly all the time, so even at dock the wing is causing active movement of the boat. Wing momentum (Mass of the assembly) causes delay in reaction to each of these gusts. So both in feather mode and while in use the wing is causing undesired lift. Challenge is size of wing, mass, shape, height, and rudder all affect the functional performance. Need to dampen undesired oscillation while reacting fast enough to wind shift to on average provide the desired level of propulsion.
All must be designed with good enough lift while avoid a bucking bronco in a slip. This bucking bronco affect is what scares most away from the pursuit in a cruising craft. The mass momentum drag of the rigid wing assembly and response dampening can play true havoc in a dangerous sea state and high winds. If your calculated lift might be 2000 lbs under optimum conditions (10-20 knots) that lift rises exponentially to like 30000 lbs at 50 knots. The problem is not the exact number but the effect that high lift is still impacting the rig even when feathed because the rig is not responding fast enough to shed that lift before the wing has loaded with wind shift. All that makes control of the boat really really difficult. There are a few experiences on the internet where wings were used in difficult conditions and the only ones claiming satisfactory results were the John Walker computerized zephyr wings where pc's were actively managing a lot of wing parameters.
So we know it can work, just how much effort is necessary manage it. Perhaps like the F-18, doesn't fly without computer support.
Of course the other alternative is get the wings down on deck in bad weather. Not yet solved that either.
So C class, manage their wing shape and angle manually (people computers) and don't go to sea in really bad weather. They will be the first to tell you they are 100% engaged in managing their wings for best performance and some ugly accidents if unable to feather effectively.
JT
--- In harryproa@yahoogroups.com.au, Dennis Cox <dec720@...> wrote:
>
> Mike,
>
> I've heard several mentions of that site in the past, but have never been on
> it. I must have spent six or seven hours last night and bookmarked a dozen
> references.
>
> Thanks,
> Dennis
>
>
>
> ________________________________
> From: Michael Gehl <mike@...>
> To: harryproa@yahoogroups.com.au
> Sent: Wed, May 18, 2011 5:14:41 PM
> Subject: Re: [harryproa] Wing Sections...
>
>
> Dennis, you might also want to dig around Multihull Anarchy in the "Wing Study
> Plans" thread, or dredge up any posts by Tom Speer, Steve Clark or blunted on
> the site. Lotta C Class and AC experience there...
>
>
> Mike
>
>
> On May 17, 2011, at 3:08 PM, Rick Willoughby wrote:
>
>
> >
> >Dennis
> >The 16 series is hard to better.
> >
> >
> >You can dial in almost anything using the modified 4 digit series.
> >
> >
> >I expect you will find a cambered section does quite a bit better but then I
> >have not compared the boat polars with the different sections; just the basic
> >wing paramaters.
> >
> >
> >Rick
> >
> >On 18/05/2011, at 5:37 AM, Dennis Cox wrote:
> >
> >
> >>
> >>Rick,
> >>
> >>Concerning the foil section of the wing for your recent design study. In your
> >>general thoroughness, I imagine you compared to more conventional, symmetric
> >>foils to get a base line. I'm wanting to start looking at some trade studies
> >>for a wing for MLM.&nb sp; I've brushed off some old my old composite and
> >>mechanics of materials spreadsheets and started getting re-familiar with
> >>JavaFoil. I am wondering if you have any suggestions and thoughts for foil
> >>shapes besides the basic NACA 0012?
> >>
> >>And if you have any opinions concerning the added complexity of a flap per...
> >>http://www.boatdesign.net/forums/multihulls/bmw-oracle-wing-33493.html#post378391
> >>
> >>... versus its benefits, I sure would dissect every word you put to electrons.
> >>
> >>Thanks,
> >>Dennis
> >>
> >>
> >
> >Rick Willoughby
> >rickwill@...
> >03 9796 2415
> >0419 104 821
> >
> >
> >
> >
>