Sail Aerodynamics
 

OK, in that case prove it. You explain 1- how tip vortex forms 2- your
calculations as to which represents a greater energy loss... flow
effects across the upper main from a frac jib, or combined tip vortex
from main + masthead jib.

If you can't explain it clearly, then you're bluffing. There is no
third alternative, is there?


MC wrote:
There is. That it would be a complete waste of my time trying to post
something you do not have the education to understand.

In other words, it's #2...


.... As for the answers to these questions #1 has already been posted by
Jax

Umm... no. I asked "Of A or B, which is better" and Jax said "yes and no."

... and others

Like who?

... many times

Golly, you can't count either.

... and #2
has no answer unless you define the exact masthead rig and fractional
rig for comparison.

OK then, what factors would affect which one is better?

...you might wonder why all the rig test show that optimal AC
genoa heads are near masthead.

I had that in mind, but those boats are influenced by measurement rules
also.

.... Pay me the money you owe me

You got that backwards too... par for the course.

.....and I'll even
have student here run it in our advanced yacht sail design wind tunnel
facility for free for you.

Oh boy... will you really do that? Put it on the list for right after
they run a simulation of a wave approaching a hull from astern to show
how the transom keeps a wave out... maybe they'll explain 'reserve
bouyancy'... right after they finish laughing...

DSK

Sail Aerodynamics
 

According to the world of Doug:

Oh boy... will you really do that? Put it on the list for right after
they run a simulation of a wave approaching a hull from astern to show
how the transom keeps a wave out...

So, now we know you have never ever sailed offshore in a big sea. Open
transoms are not generally acceptable for really just one reason Doug,
even with no difference in 'buoyancy'. Can you really not imagine a sea
overtaking a running boat? The stern really doesn't rise immediately you
know! In some cases it even goes over the transom and can hit the helm
and even companion washboards. What on earth do you think stops it?
You've got Adlard Coles Heavy Weather right? Have a look at the boat
being overtaken by a wave. What a typical know it all dinghy sailor you
are.

Cheers

Sail Aerodynamics
 

read it again, dougie. And again, if need be. And again. And again. And
again ...

JAXAshby wrote:
dougies, I gave you the answer. read it again. And again, if you need to.

And again. And again.

Slow dow, Jax, you're backpeddling so fast you're almost out of sight

Wouldn't it be easier to be honest... just admit you don't have a clue.
You'll feel better and your therapist will be proud of you.

DSK

Sail Aerodynamics
 

He won't get it. He'ss incapable of original thought and his
comprehension suffers accordingly.

Cheers

JAXAshby wrote:

read it again, dougie. And again, if need be. And again. And again. And
again ...


JAXAshby wrote:

dougies, I gave you the answer. read it again. And again, if you need to.

And again. And again.

Slow dow, Jax, you're backpeddling so fast you're almost out of sight

Wouldn't it be easier to be honest... just admit you don't have a clue.
You'll feel better and your therapist will be proud of you.

DSK

Sail Aerodynamics
 

DSK wrote:


OK, in that case prove it. You explain 1- how tip vortex forms 2-
your calculations as to which represents a greater energy loss...
flow effects across the upper main from a frac jib, or combined tip
vortex from main + masthead jib.

If you can't explain it clearly, then you're bluffing. There is no
third alternative, is there?


MC wrote:
There is. That it would be a complete waste of my time trying to post
something you do not have the education to understand.


In other words, it's #2...

Nope, its exactly as I wrote. I won't waste my time explain any
complicated problems to someone who is incapable of undertstanding them.
That's why I only try to simplify a few thing that you might begin to
get the idea. Of course I'm probably wasting my time with a bigot.

Cheers

Sail Aerodynamics
 

DSK wrote:



... and #2 has no answer unless you define the exact masthead rig and
fractional rig for comparison.


OK then, what factors would affect which one is better?


Rig geometry of course! This reminds me of children who are too
lazy/stupid to frame a question properly and don't really want to know
the answer but just get attention. They just keep saying "But why..."

Cheers

Sail Aerodynamics
 

MC wrote:
So, now we know you have never ever sailed offshore in a big sea.

Sure, whatever you say. You're as right about this as you are about
aerodynamics... oh wait, you haven't said anything substantive about
aerodynamics, in fact you are vigorously dodging any & all questions...

..... Open
transoms are not generally acceptable for really just one reason Doug,

What you mean to say is that open transoms are not acceptable to _you_.
Oddly enough many others have sailed lots of sea miles with them. So
your comments about how terrible they are show your ownlack of
experience and comprehension.


.... What a typical know it all dinghy sailor you
are.

This thread is following the classic pattern... MC bluffs, he blunders,
he dodges & prevaricates... then he starts with insults. It becomes
obvious that he can't answer the question. Does this pattern fulfill a
psychological need for you, Navvie? How many times will you be driven to
repeat it?

DSK

Sail Aerodynamics
 

OK then, what factors would affect which one is better?


MC wrote:
Rig geometry of course!


Now we are getting somewhere.

What rig geometery would favor a frac rig (remembering the issue of jib
head tip vortex)? Would aspect ratio be significant (again, just a
reminder, jib head tip vortex)? How about the head angle of each sail
respectively?


... This reminds me of children who are too
lazy/stupid to frame a question properly and don't really want to know
the answer but just get attention. They just keep saying "But why..."

So, even your toddlers are asking you questions that you don't know the
answer to?

All you have to do MC is supply a coherent answer to the question.

DSK

Sail Aerodynamics
 

oh wait, you haven't said anything substantive about
aerodynamics,

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.

Sail Aerodynamics
 

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

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

Would aspect ratio be significant (again, just a
reminder, jib head tip vortex)?

Of course.

How about the head angle of each sail
respectively?

WTF are you talking about?

dougies, give it up for the cripes sakes. you read a single article by a
numskull about vortices and now you are trying to play expert. Go read a few
dozen more books. A good start would be check a few of the books offered by
the EAA, mostly decent books written for the amateur.