composite wing, wing spars

[Dave Schneider]

This may be only slightly off topic, but I'm building a foam core solid wing
for an iceboat/land yacht. I'm familiar with R/C model airplane foam core
wings, but I'm not sure how to scale that up for what I'm doing.

Here are the specs:
49 square feet
pluggable sections (one 10 foot section, and one 6 foot section)
wing is stayed at the 10 foot mark.
main foil and flap ratio is 60%/40% respectively
Something like 4' chord at the bottom, 2' chord at the top (main + flap)
sheeted with probably 3/32 ply


I'm looking for optinions, book references, and/or online links for helping
me out. Specific questions are:
- how to build the main spar. I'm thinking a glass/carbon wrapped box spar
that allows plugging in the top section
- do I need more than the main spar?
- I'm looking at affordable, not the utimate in light weight.

If your interested, here is a discussion group talking about various design
aspects of solid wing sails. If your really interested, your welcome to
join the discussion group.
http://groups.msn.com/LandsailerandIceboatdesignandconstruction

Here is one construction method that works:
http://groups.msn.com/LandsailerandIceboatdesignandconstruction/constructionalbum.msnw?action=ShowPhoto&PhotoID=24

Thanks in advance
Dave

[StellaStar]

> I'm building a foam core solid wing
>for an iceboat/land yacht.

I'm curious...aside from the discussion of "luff tension" et al, what's the
benefit of a solid sail?

My dad built an iceboat and I have vivid early-childhood memories of skimming
along, face inches from the ice of the lake, going at what seemed a terrific
rate of speed. Aside from the usual risk of getting clobbered by the boom when
it comes around, managing the sail didn't seem to be a problem for him, and I'd
think it would give you more versatility, not to mention being easy to wrap up
and tote.

[Dave Schneider]

I'm not the person to ask why. However I understand that they point higher
and are much more efficient. This concept isn't out in left field.
Remember the America's Cup catamaran with a solid wing sail?


"StellaStar" > wrote in message
...
> > I'm building a foam core solid wing
> >for an iceboat/land yacht.
>
> I'm curious...aside from the discussion of "luff tension" et al, what's
the
> benefit of a solid sail?
>
> My dad built an iceboat and I have vivid early-childhood memories of
skimming
> along, face inches from the ice of the lake, going at what seemed a
terrific
> rate of speed. Aside from the usual risk of getting clobbered by the boom
when
> it comes around, managing the sail didn't seem to be a problem for him,
and I'd
> think it would give you more versatility, not to mention being easy to
wrap up
> and tote.

[Bill Daniels]

A sailboat sail is just a wing stood on end. A single surface, non-rigid
sail is like a hang glider. A solid two-surface sail is like a sailplane
wing - far more efficient. An ultra-light, carbon fiber, rigid sail offers
a potentially huge increase in performance.

Of course, with a sailboat, there is another wing to be concerned with and
that is the one below water - the keel. The keel or centerboard provides
the purchase against which the forces generated by the main sail work. A
hydrodynamically optimized keel and an aerodynamically optimized sail can
provide a really big propulsive force. Combine it with a sleek hull and the
boat can go far and fast.

Fixed keels and rigid sails increase the difficulties of operating the boat
but these can be dealt with.

Bill Daniels

"Dave Schneider" > wrote in message
...
> I'm not the person to ask why. However I understand that they point
higher
> and are much more efficient. This concept isn't out in left field.
> Remember the America's Cup catamaran with a solid wing sail?
>
>
> "StellaStar" > wrote in message
> ...
> > > I'm building a foam core solid wing
> > >for an iceboat/land yacht.
> >
> > I'm curious...aside from the discussion of "luff tension" et al, what's
> the
> > benefit of a solid sail?
> >
> > My dad built an iceboat and I have vivid early-childhood memories of
> skimming
> > along, face inches from the ice of the lake, going at what seemed a
> terrific
> > rate of speed. Aside from the usual risk of getting clobbered by the
boom
> when
> > it comes around, managing the sail didn't seem to be a problem for him,
> and I'd
> > think it would give you more versatility, not to mention being easy to
> wrap up
> > and tote.
>
>

[Thad Beier]

Of course the above-mentioned America's Cup catamaran's wing
was built by (wait for it) Burt Rutan. They had a nice picture
of the Mojave Yacht Club in a book about the boat.

That cat, Stars and Stripes (they're all called Stars and Stripes)
was clocked at sailing 17 knots in an 8 knot breeze, truly an
amazing achievement. They mounted a conventional spinnaker on
the boat to slow it down, so it wouldn't beat the Kiwi boat
by as much as it would otherwise.

Thad