New Posts New Posts RSS Feed: Foils
  FAQ FAQ  Forum Search   Register Register  Login Login

Foils
 Post Reply Post Reply Page  12>
Author
  Share Topic Share Topic  Topic Search Topic Search  Topic Options Topic Options
JimC View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 17 May 04
Location: United Kingdom
Online Status: Offline
Posts: 6662 		Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Topic: Foils
    Posted: 02 Oct 06 at 6:44pm
Originally posted by timnoyce

and surely if you heel to windward the foils produce upward lift which is not only lifting the boat out of the water but also forcing the boat upwind more?

You don't really force the boat upwind more, resisting leeway is resisting leeway to a good extent. The really neat trick about the winward heel is that a foil meeting the water with side load on creates tons more drag than one which is not side loaded. Because all the sideload is on under the water foils drag is even lower!
Back to Top
mike ellis View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 30 Dec 05
Location: United Kingdom
Online Status: Offline
Posts: 2339 		Post Options Post Options   Quote mike ellis Quote  Post ReplyReply Direct Link To This Post Posted: 02 Oct 06 at 6:01pm

oh, ok

i suppose they would only get lee helm if they had bigger rudder foils than dagger foils. i think

600 732, will call it Sticks and Stones when i get round to it.
Also International 14, 1318
Back to Top
timnoyce View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 05 Aug 04
Location: Hampshire
Online Status: Offline
Posts: 1991 		Post Options Post Options   Quote timnoyce Quote  Post ReplyReply Direct Link To This Post Posted: 02 Oct 06 at 5:58pm
and surely if you heel to windward the foils produce upward lift which is not only lifting the boat out of the water but also forcing the boat upwind more?
BEARFOOT DESIGN
Cherub 2648 - Comfortably Numb
Back to Top
BBSCFaithfull View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 06 Dec 05
Location: United Kingdom
Online Status: Offline
Posts: 1251 		Post Options Post Options   Quote BBSCFaithfull Quote  Post ReplyReply Direct Link To This Post Posted: 02 Oct 06 at 5:47pm
they heel to windward to use the tfoils as a daggerboard of sorts i believe
Greatfully Sponsored By
www.allgoodfun.com
Int 14 GBR 1503!!
Back to Top
mike ellis View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 30 Dec 05
Location: United Kingdom
Online Status: Offline
Posts: 2339 		Post Options Post Options   Quote mike ellis Quote  Post ReplyReply Direct Link To This Post Posted: 02 Oct 06 at 5:39pm

Originally posted by Blobby

(at least, when the boat is perfectly upright - as soon as you heel the lift from the t-foil also has a bit of sideways component so steers the boat too...)

so does that mean the moths have to sail with constant lee helm when they are on their foils?
600 732, will call it Sticks and Stones when i get round to it.
Also International 14, 1318
Back to Top
Blobby View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 07 May 04
Location: Australia
Online Status: Offline
Posts: 779 		Post Options Post Options   Quote Blobby Quote  Post ReplyReply Direct Link To This Post Posted: 02 Oct 06 at 6:47am
Because the whole stock moves you are changing the angle of the hinge so the blade stays in the same place relative to the hinge so no change in tiller loads (at least, when the boat is perfectly upright - as soon as you heel the lift from the t-foil also has a bit of sideways component so steers the boat too...)
One step forwards, 2 steps back...
Back to Top
C. Petrie View Drop Down
Groupie
Groupie
Avatar

Joined: 17 Jan 05
Online Status: Offline
Posts: 43 		Post Options Post Options   Quote C. Petrie Quote  Post ReplyReply Direct Link To This Post Posted: 01 Oct 06 at 9:33pm

Just out of curiosity, how much does the bottom of the blade move fore and aft? Surely this would affect the helm characteristics? or is the movement so slight that the difference is minimal? - just thinking with regard to when I sailed a laser, if the blade wasn't fully down you knew about it!
Back to Top
Granite View Drop Down
Far too distracted from work
Far too distracted from work
Avatar

Joined: 12 May 04
Location: Scotland
Online Status: Offline
Posts: 476 		Post Options Post Options   Quote Granite Quote  Post ReplyReply Direct Link To This Post Posted: 01 Oct 06 at 9:12pm
The rudder and Gantry on AquaMarina with the blade of the T fixed in the rudder, the stock rotates to change the angle of attack.

this is with the rudder almost full negative,. no lift for going down wind



The adjuster full positive for max lift when going up wind.



A close up of the adjuster, the rod pushes against the pintle to move the rudder stock.



One of the other ways to do it is to have the blades fo the T-foil rotate on an axle in the blade of the rudder, this is a bit trickier to make but is popular in the 14's.
If it doesn't break it's too heavy; if it does it wasn't built right
Back to Top
Jack Sparrow View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 08 Feb 05
Location: United Kingdom
Online Status: Offline
Posts: 2965 		Post Options Post Options   Quote Jack Sparrow Quote  Post ReplyReply Direct Link To This Post Posted: 30 Sep 06 at 11:51am
this one basically rocks around the bottom pintal on your normal rod. and you can see the rudder blade lock dangerling on a bit of string.
Farr 3.7 Class Website
Farr 3.7 Building - Facebook Group
Back to Top
tgruitt View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 02 Dec 04
Online Status: Offline
Posts: 2479 		Post Options Post Options   Quote tgruitt Quote  Post ReplyReply Direct Link To This Post Posted: 30 Sep 06 at 11:39am


This is our rudder on the Cherub. The stock is fixed with a metal rod on which the angle of attack is adjusted. The blade is pushed down through the stock and fixed in place by the aluminium tube at the top. Thats about it really!
Needs to sail more...
Back to Top
 Post Reply Post Reply Page  12>

Forum Jump Forum Permissions View Drop Down

Bulletin Board Software by Web Wiz Forums® version 9.665y
Copyright ©2001-2010 Web Wiz
Change your personal settings, or read our privacy policy