On 14 Aug 2004 12:40:52 GMT, (JAXAshby) wrote:

If you understand a wing you are 3/4 of the way there.

no, 100%. airfoils don't know whether they are vertical or horizontal.

So?

so, if you undestand a wing you 100% of the way there, not 3/4.


The keel must be taken into consideration when sailing upwind.
Airplanes move in one medium, sailboats move in two.

Jack

__________________________________________________
Jack Dale
Swiftsure Sailing Academy
Director/ISPA and CYA Instructor
http://www.swiftsuresailing.com
Phone: 1 (877) 470-SAIL (toll free)
__________________________________________________

Thanks a lot for the illuminating answers. I read somewhere that the
"sail-as-airfoil" trick is a rather recent one, and that formerly
people would just let the wind push them around. Is that true, and if
yes, how recent is the invention?

Thanks,
Axel

no, the keel has not a thing to do with understanding how a sail works.
nothing.

it does have something to do with how a sailboat works, but not a thing on how
a sail works.

If you understand a wing you are 3/4 of the way there.

no, 100%. airfoils don't know whether they are vertical or horizontal.

So?

so, if you undestand a wing you 100% of the way there, not 3/4.


The keel must be taken into consideration when sailing upwind.
Airplanes move in one medium, sailboats move in two.

Jack

_________________________________________________ _
Jack Dale
Swiftsure Sailing Academy
Director/ISPA and CYA Instructor
http://www.swiftsuresailing.com
Phone: 1 (877) 470-SAIL (toll free)
_________________________________________________ _

sails always worked as sails work. the thinking about them has changed, but
airfoils are airfoils, and have been since birds learned to fly a bit back.

Thanks a lot for the illuminating answers. I read somewhere that the
"sail-as-airfoil" trick is a rather recent one, and that formerly
people would just let the wind push them around. Is that true, and if
yes, how recent is the invention?

Thanks,
Axel

Are you claiming the keel has nothing to do with going upwind? How jaxian of
you to say that.



"JAXAshby" wrote in message
...
no, the keel has not a thing to do with understanding how a sail works.
nothing.

it does have something to do with how a sailboat works, but not a thing on how
a sail works.

If you understand a wing you are 3/4 of the way there.

no, 100%. airfoils don't know whether they are vertical or horizontal.

So?

so, if you undestand a wing you 100% of the way there, not 3/4.


The keel must be taken into consideration when sailing upwind.
Airplanes move in one medium, sailboats move in two.

Jack

_________________________________________________ _
Jack Dale
Swiftsure Sailing Academy
Director/ISPA and CYA Instructor
http://www.swiftsuresailing.com
Phone: 1 (877) 470-SAIL (toll free)
_________________________________________________ _

Square-rigged boats could sail no higher than a beam reach. However, the sails
were not flat, and they were trimmed appropriately to allow the boats to be
sailed other than dead downwind.

I don't recall the date triangular sails were invented, but they were the dawn
of upwind sailing in the west; junk rigs enabled upwind sailing in the east.

"Axel Boldt" wrote...
Thanks a lot for the illuminating answers. I read somewhere that the
"sail-as-airfoil" trick is a rather recent one, and that formerly
people would just let the wind push them around. Is that true, and if
yes, how recent is the invention?

On 14 Aug 2004 17:19:25 GMT, (JAXAshby) wrote:

no, the keel has not a thing to do with understanding how a sail works.
nothing.

it does have something to do with how a sailboat works, but not a thing on how
a sail works.


You are correct.

But the initial posting was :"I'm trying to understand how a boat can
sail against the wind."

Understanding the sail as airfoil is not 100% of the answer. One must
also consider the effect of the keel.

Jack

__________________________________________________
Jack Dale
Swiftsure Sailing Academy
Director/ISPA and CYA Instructor
http://www.swiftsuresailing.com
Phone: 1 (877) 470-SAIL (toll free)
__________________________________________________

no [head shakes], jeffies. I did not say that. please ask your wife to read
it for you.

Are you claiming the keel has nothing to do with going upwind? How jaxian
of
you to say that.



"JAXAshby" wrote in message
...
no, the keel has not a thing to do with understanding how a sail works.
nothing.

it does have something to do with how a sailboat works, but not a thing on
how
a sail works.

If you understand a wing you are 3/4 of the way there.

no, 100%. airfoils don't know whether they are vertical or horizontal.

So?

so, if you undestand a wing you 100% of the way there, not 3/4.


The keel must be taken into consideration when sailing upwind.
Airplanes move in one medium, sailboats move in two.

Jack

_________________________________________________ _
Jack Dale
Swiftsure Sailing Academy
Director/ISPA and CYA Instructor
http://www.swiftsuresailing.com
Phone: 1 (877) 470-SAIL (toll free)
_________________________________________________ _

Axel Boldt wrote:
Thanks a lot for the illuminating answers. I read somewhere that the
"sail-as-airfoil" trick is a rather recent one, and that formerly
people would just let the wind push them around. Is that true, and if
yes, how recent is the invention?

Thanks,
Axel

umm... it's probably a "AD" date rather than a "BC" but there are
designs of sails which are pretty ancient that do run as proper
airfoils, not just a drag device. The Arab Lateen rigs are I think
pretty old, as an example.

Remember what Cook found in the south seas? The native canoes "went
about three miles to our two" - European rigs were not the hottest thing
at the time.

Andy.

my statement was in respone to the secondary posting that said understanding
wing arifoils was 3/4 of understanding sail airfoils.

no, the keel has not a thing to do with understanding how a sail works.
nothing.

it does have something to do with how a sailboat works, but not a thing on
how
a sail works.


You are correct.

But the initial posting was :"I'm trying to understand how a boat can
sail against the wind."

Understanding the sail as airfoil is not 100% of the answer. One must
also consider the effect of the keel.

Jack

_________________________________________________ _
Jack Dale
Swiftsure Sailing Academy
Director/ISPA and CYA Instructor
http://www.swiftsuresailing.com
Phone: 1 (877) 470-SAIL (toll free)
_________________________________________________ _