Sail Aerodynamics
 

What rig geometery would favor a frac rig (remembering the issue of jib
head tip vortex)?

JAXAshby wrote:
in the context of jib tip vortices, a masthead rig would be better.

Well, that's still not the question I asked, but at least it's an answer. Now,
please explain why.



How about the head angle of each sail
respectively?

WTF are you talking about?

You don't know? It seems pretty simple and obvious to me, and probably to
everyone else too.

The head angle of a sail is the angle the leach forms with the luff at the head
of the sail. This is somewhat related to aspect ratio but is not at all fixed to
it. For example, a sprit or a gaff are low aspect but with large head angles. On
the opposite side, you find high aspect modern sloops with conventional battens
and rather pointy tops to their sails.

Now that you know what head angle is, can you make any statement about it's
effect on the interaction between the jib head vortex and the rest of the sail
plan?

(trying not to laugh, honestly)- Doug King

Sail Aerodynamics
 

JAXAshby wrote:

.. I also said you had read a single book or article written by a guy
who didn't even know that the plural of vortex is votices.

Wrong.

I have never read a single book about vortexes.

However, in many of my physics & engineering textbooks there are quite a few
chapters that talk about them. Of course, you're a LOT smarter than science &
engineering professors who just sit around writing books and teaching people,
aren't you Jax? The voices tell you so!

DSK

Sail Aerodynamics
 

you dumb squat, dougies. I *did* explain why, several posts ago. too many big
words for you?

JAXAshby wrote:
in the context of jib tip vortices, a masthead rig would be better.

Well, that's still not the question I asked, but at least it's an answer.
Now,
please explain why.

Sail Aerodynamics
 

boy you are a dumb squat, dougies. Like I said, you don't know WTF you're
talking about.

you are _trying_ to deal with planform shape but aren't even close. The least
tip vortex formation comes with the highest aspect ratio. what you are
_trying_ to discuss but don't understand is spanwise loading, which also has an
effect on vortex generation but that is not the reason for eliptical planforms.

now, go read the same book again and again and again by three different
ill-informed writers all plagarizing from some other ill-informed writer.
Otherwise, go you a major university bookstore and pick up some 3rd or 4th year
aero eng textbooks. If that is too tough for you, try the EAA for pretty
decent books on the subject written for the uneducated.

How about the head angle of each sail
respectively?

WTF are you talking about?

You don't know? It seems pretty simple and obvious to me, and probably to
everyone else too.

The head angle of a sail is the angle the leach forms with the luff at the
head
of the sail. This is somewhat related to aspect ratio but is not at all fixed
to
it. For example, a sprit or a gaff are low aspect but with large head angles.
On
the opposite side, you find high aspect modern sloops with conventional
battens
and rather pointy tops to their sails.

Now that you know what head angle is, can you make any statement about it's
effect on the interaction between the jib head vortex and the rest of the
sail
plan?

(trying not to laugh, honestly)- Doug King

Sail Aerodynamics
 

dougies, the way you talk gibberish about science the only way you might come
in contact with a physics or engineering textbooks is by cleaning the college
bookstore floors at night.

btw, electrical, electronic, mechanical, chemical engineers -- none of them --
have any textbooks about vor-ti-SEEEEEEES.

I have never read a single book about vortexes.

However, in many of my physics & engineering textbooks there are quite a few
chapters that talk about them. Of course, you're a LOT smarter than science &
engineering professors who just sit around writing books and teaching people,
aren't you Jax? The voices tell you so!

DSK

Sail Aerodynamics
 

JAXAshby wrote:

boy you are a dumb squat, dougies.

Still not an answer Jaxxie.

Like I said, you don't know WTF you're
talking about.

Wrong... you don't, I do.


you are _trying_ to deal with planform shape but aren't even close.

Closer, Jaxxie, closer... head angle is related to planform but the two are not at
all the same thing.


The least
tip vortex formation comes with the highest aspect ratio.

So, are you saying that head angle is always proportional to aspect ratio? Or are
you saying that aspect ratio affects tip vortex but head angle does not?

In any event, all sorts of things can affect tip vortex with the exact same aspect
ratio or even planform. This is basically the same thing I was trying to explain in
my last post. I'll keep on trying Jax, don't worry.


what you are
_trying_ to discuss but don't understand is spanwise loading, which also has an
effect on vortex generation but that is not the reason for eliptical planforms.

Funny, it seems that now we are hopping from aspect ratio to spanwise loading,
which is a result of pressure distribution, which I already mentioned... and you
seem to be groping for the answer that elliptical planforms aren't intended to
reduce tip vortex? How is that relevant?

Tell me something Jax... when was the last time you saw a sailboat with elliptical
planform sails?

Anyway, pressure distribution is one big reason for tip vortex formation....
getting this out of you is almost like pulling teeth, as you stumble through the
fog of all your half-memorized buzzwords. But it is not the whole story, or else
winglets wouldn't be as effective as they are.

Now, can we get back to the original question? We can change over and discuss hull
speed if you prefer.

DSK

Sail Aerodynamics
 

dougies, you read three books with three differenct titles from three different
authors, all of whom plagarized from yet another writer who really didn't know
from squat, and THAT makes you an expert?

dougies, I have repeatedly suggested you read a book by someone who knows.

the more you write, the more gullible you sound.

now, go learn something. and take your candle with you.

geesh, there was a reason the high school chemistry teacher wouldn't let
dougies anywhere near matches.


JAXAshby wrote:

boy you are a dumb squat, dougies.

Still not an answer Jaxxie.

Like I said, you don't know WTF you're
talking about.

Wrong... you don't, I do.


you are _trying_ to deal with planform shape but aren't even close.

Closer, Jaxxie, closer... head angle is related to planform but the two are
not at
all the same thing.


The least
tip vortex formation comes with the highest aspect ratio.

So, are you saying that head angle is always proportional to aspect ratio? Or
are
you saying that aspect ratio affects tip vortex but head angle does not?

In any event, all sorts of things can affect tip vortex with the exact same
aspect
ratio or even planform. This is basically the same thing I was trying to
explain in
my last post. I'll keep on trying Jax, don't worry.


what you are
_trying_ to discuss but don't understand is spanwise loading, which also
has an
effect on vortex generation but that is not the reason for eliptical
planforms.

Funny, it seems that now we are hopping from aspect ratio to spanwise
loading,
which is a result of pressure distribution, which I already mentioned... and
you
seem to be groping for the answer that elliptical planforms aren't intended
to
reduce tip vortex? How is that relevant?

Tell me something Jax... when was the last time you saw a sailboat with
elliptical
planform sails?

Anyway, pressure distribution is one big reason for tip vortex formation....
getting this out of you is almost like pulling teeth, as you stumble through
the
fog of all your half-memorized buzzwords. But it is not the whole story, or
else
winglets wouldn't be as effective as they are.

Now, can we get back to the original question? We can change over and discuss
hull
speed if you prefer.

DSK

Sail Aerodynamics
 

It are?

OzOn wrote in message ...
On 28 Jan 2004 13:15:16 GMT, (JAXAshby) scribbled
thusly:



but I did. I also said you had read a single book or article written by
a guy
who didn't even know that the plural of vortex is votices.


Oh oh, Jax has that paintbrush out again

vor·tex ( P ) Pronunciation Key (vôrtks)
n. pl. vor·tex·es or vor·ti·ces (-t-sz)
www.dictionary.com.

You could say you're sorry.


Oz1...of the 3 twins.

I welcome you to crackerbox palace,We've been expecting you.

Sail Aerodynamics
 

DSK wrote:

What rig geometery would favor a frac rig (remembering the issue of jib
head tip vortex)?

JAXAshby wrote:
in the context of jib tip vortices, a masthead rig would be better.


Well, that's still not the question I asked, but at least it's an answer. Now,
please explain why.



How about the head angle of each sail
respectively?

WTF are you talking about?


You don't know? It seems pretty simple and obvious to me, and probably to
everyone else too.

The head angle of a sail is the angle the leach forms with the luff at the head
of the sail. This is somewhat related to aspect ratio but is not at all fixed to
it. For example, a sprit or a gaff are low aspect but with large head angles. On
the opposite side, you find high aspect modern sloops with conventional battens
and rather pointy tops to their sails.

Now that you know what head angle is, can you make any statement about it's
effect on the interaction between the jib head vortex and the rest of the sail
plan?


If he can you won't understand it.

Cheers
(trying not to laugh, honestly)- Doug King

Sail Aerodynamics
 

DSK wrote:

JAXAshby wrote:


.. I also said you had read a single book or article written by a guy
who didn't even know that the plural of vortex is votices.


Wrong.

I have never read a single book about vortexes.

However, in many of my physics & engineering textbooks there are quite a few
chapters that talk about them.

Good lord. Next you'll be saying you understand mathematics.

Cheers