Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-02-2013, 14:22   #46
Moderator
 
noelex 77's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: Living on dirt waiting for our new yacht to be built.
Boat: Half built Bestevaer.
Posts: 10,619
Re: Settle an argument

Quote:
Originally Posted by Adelie View Post
Even in a aerobatic plane the range would be significantly decreased, the angle of attack for the fuselage and empenage would be significantly changed.
Some modern aerobatic aircraft have 0,0,0 rigging (0 degrees wing incidence, tail incidence, dihedral) and of course a symetrical aerofoil.
__________________

__________________
noelex 77 is offline   Reply With Quote
Old 11-02-2013, 14:28   #47
Registered User

Join Date: Mar 2008
Location: Akron, Ohio
Boat: Bristol 29(1967)
Posts: 595
Re: Settle an argument

Unless this is a "really friendly", argument . . . you can't win . . . don't try to win.

Give him a book about sailing and invite him to sail with you.

__________________

__________________
SURV69 is offline   Reply With Quote
Old 11-02-2013, 14:31   #48
Moderator
 
Hudson Force's Avatar

Cruisers Forum Supporter

Join Date: Nov 2008
Location: Lived aboard & cruised for 45 years,- now on a chair in my walk-in closet.
Boat: Morgan OI 413 1973 - Aythya
Posts: 7,894
Images: 1
Re: Settle an argument

Quote:
Originally Posted by Bash View Post
.............The real question isn't science--it's engineering: just how are you going to keep a flat sail flat?
I'm totally lost with this,- "... isn't science--it's engineering". That's like saying it isn't a bird--it's a duck!
__________________
Take care and joy, Aythya crew
Hudson Force is offline   Reply With Quote
Old 11-02-2013, 14:32   #49
Registered User

Join Date: May 2012
Location: Central California
Boat: Catalina 30
Posts: 873
Re: Settle an argument

I know of no birds whose wings are not...well...wing shaped. I wonder, why is that?
__________________
Bill
...........................................
You can't buy happiness, but you can buy ribeye.
jongleur is offline   Reply With Quote
Old 11-02-2013, 14:37   #50
Moderator
 
noelex 77's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: Living on dirt waiting for our new yacht to be built.
Boat: Half built Bestevaer.
Posts: 10,619
Re: Settle an argument

Quote:
Originally Posted by SURV69 View Post
Unless this is a "really friendly", argument . . . you can't win . . . don't try to win.
If the argument gets difficult, just say "everything is great in bedroom" . I bet FIL changes the subject to the weather, sport, or politics
__________________
noelex 77 is offline   Reply With Quote
Old 11-02-2013, 16:12   #51
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,331
Re: Settle an argument

Quote:
Originally Posted by Tscott8201 View Post
Ok, had a friendly argument with my father in law this weekend. Last time we rented a sailboat for a day the instructor commented on the importance of sail trimming due to the fact the sail is basically a wing. Later on that day my father in law brings up that he believes this is all mumbo jumbo and that the "wing effect" is basically oversold. He claims that a perfectly workable sail could be made out of a flat solid sheet of material with no curve and you would get decent performance out of it. Not as good a a curved sail, but almost as good. I told him it might work but would basically be crap and give little to no forward thrust. Who is right?

Tom
Quote:
Originally Posted by Adelie View Post
Sailing dead downwind, FIL is 70% right, a cupped shape will provide more drive downwind than a flat plate.
Hmm... 70% can be considered in some circumstances as "almost" so I maintain FIL was 100% correct in his assessment when DDW.

Quote:
Originally Posted by Cheechako View Post
Never argue with the FIL, even when he's wrong as in this case!
Quote:
Originally Posted by noelex 77 View Post
If the argument gets difficult, just say "everything is great in bedroom" . I bet FIL changes the subject to the weather, sport, or politics
Which brings us to the question "who / what does the significant daughter believe"?
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is online now   Reply With Quote
Old 11-02-2013, 16:29   #52
Registered User
 
RainDog's Avatar

Join Date: Jun 2009
Location: Varies
Boat: Pacific Seacraft 34 #142
Posts: 1,183
Re: Settle an argument

RainDog is offline   Reply With Quote
Old 11-02-2013, 16:30   #53
Registered User

Join Date: Dec 2008
Location: ontario canada
Boat: grampian 26
Posts: 1,743
Re: Settle an argument

Quote:
Originally Posted by Adelie View Post
Huh?!?

The CF 104 Starfighter was basically a big jet engine with stubby thin wings and razor sharp leading edges which proved that even a brick will develope lift if you move it fast enough.
__________________
perchance is offline   Reply With Quote
Old 11-02-2013, 16:36   #54
Registered User

Join Date: May 2011
Posts: 9
Re: Settle an argument

The sail does act like a wing, it's basic physics. High pressure air going over the outside of the sail meets lower pressured air on the back side of the sail resulting in a vacuum that creates lift. Works the same whether your sail/wing is horizontal or vertical. Of course sailing directly downwind is another story. Oh it's called Bernoulli's Principle if anyone would care to look it up. I'm not smart enough for all the math, but the basics are solid.
__________________
DutchAW is offline   Reply With Quote
Old 11-02-2013, 16:44   #55
CF Adviser
 
Bash's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: sausalito
Boat: 14 meter sloop
Posts: 7,260
Re: Settle an argument

Quote:
Originally Posted by CaptForce View Post
I'm totally lost with this,- "... isn't science--it's engineering".
Thinking of the latter as the application of the former.

Why sails shaped as airfoils are faster than flat sails is a science question.

How to maintain specific airfoil shapes would be an engineering question.
__________________
cruising is entirely about showing up--in boat shoes.
Bash is offline   Reply With Quote
Old 11-02-2013, 16:46   #56
Nearly an old salt
 
goboatingnow's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Posts: 13,649
Images: 3
Quote:
Originally Posted by DutchAW
The sail does act like a wing, it's basic physics. High pressure air going over the outside of the sail meets lower pressured air on the back side of the sail resulting in a vacuum that creates lift. Works the same whether your sail/wing is horizontal or vertical. Of course sailing directly downwind is another story. Oh it's called Bernoulli's Principle if anyone would care to look it up. I'm not smart enough for all the math, but the basics are solid.
Bernoulli's principles used to explain flight have large been debunked

Have read of http://www.grc.nasa.gov/WWW/k-12/airplane/wrong1.html

It's all about vortexes and turning the fluid , FIL is right, lift would be generated using a flat sail, say one made out of rigid composite material, not as efficient as a foil of course.

Dave
__________________
Check out my new blog on smart boat technology, networking and gadgets for the connected sailor! - http://smartboats.tumblr.com
goboatingnow is offline   Reply With Quote
Old 11-02-2013, 17:23   #57
Marine Service Provider

Join Date: Aug 2010
Location: north carolina
Boat: command yachtsdouglas32
Posts: 3,113
Re: Settle an argument

Quote:
Originally Posted by cal40john View Post
I am very confused. Are you saying the link I posted had anything to do with Bernoulli, because it doesn't.
Part 11 other theories...
__________________
tropicalescape is offline   Reply With Quote
Old 11-02-2013, 17:31   #58
Moderator
 
Adelie's Avatar

Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 4,615
Re: Settle an argument

Quote:
Originally Posted by cfarrar View Post
True, but most sailboats are symmetrical. Ie, they are not designed to create greater lift on one tack than the other. So, FIL is mostly correct, after all!
The whole plane thing was thread drift very tenuously related to the OP's question.

The symmetry of a sailboat has no bearing on whether flat plate will perform just as well when substituting for a sail with draft.
__________________
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
SailboatData
Adelie is offline   Reply With Quote
Old 11-02-2013, 17:36   #59
Moderator
 
Adelie's Avatar

Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 4,615
Re: Settle an argument

Quote:
Originally Posted by RainDog View Post
Just goes to show you that if you apply enough power anything will fly.

There was once an F-15 that lost a wing. Pilot landed the plane just on the lift provided by the fuselage.
__________________
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
SailboatData
Adelie is offline   Reply With Quote
Old 11-02-2013, 17:37   #60
Moderator
 
Adelie's Avatar

Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 4,615
Re: Settle an argument

Quote:
Originally Posted by perchance View Post
The CF 104 Starfighter was basically a big jet engine with stubby thin wings and razor sharp leading edges which proved that even a brick will develope lift if you move it fast enough.
The apparent non-sequitor baffled me.

Actually it was the trailing edges that were razor sharp, though the leading edges were also sharp enough to cut.
__________________

__________________
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
SailboatData
Adelie is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 01:33.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.