Foils
Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Dinghy development
Forum Discription: The latest moves in the dinghy market
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=2255
Printed Date: 17 Aug 25 at 6:46am
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com
Topic: Foils
Posted By: Dangerousday
Subject: Foils
Date Posted: 30 Sep 06 at 12:34am
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As there is are increasing discussions over T-foil rudders and foils I'm curious about them, never having actually seen any in the flesh, how are the rudders attached to the transom? I'm assuming there is a vertically upward force created by these rudders, so the regular arrangement of pintles to drop the rudder on, with a springy clip to stop it dropping off when capsized/turtled won't work as it wouldn't an upwards load. So how's it done? Anyone got a picture or link? |
Replies:
Posted By: m_liddell
Date Posted: 30 Sep 06 at 11:27am
| I have a load of pics of one of the top 14's rudder assembly and also primal scream's (cherub). If you want them give me your email. |
Posted By: tgruitt
Date 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... |
Posted By: Jack Sparrow
Date 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. ------------- http://www.uk3-7class.org/index.html" rel="nofollow - Farr 3.7 Class Website https://www.facebook.com/groups/1092602470772759/" rel="nofollow - Farr 3.7 Building - Facebook Group |
Posted By: Granite
Date Posted: 01 Oct 06 at 9:12pm
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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 |
Posted By: C. Petrie
Date Posted: 01 Oct 06 at 9:33pm
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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! |
Posted By: Blobby
Date Posted: 02 Oct 06 at 6:47am
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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... |
Posted By: mike ellis
Date Posted: 02 Oct 06 at 5:39pm
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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 |
Posted By: BBSCFaithfull
Date Posted: 02 Oct 06 at 5:47pm
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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!! |
Posted By: timnoyce
Date Posted: 02 Oct 06 at 5:58pm
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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?
------------- http://www.facebook.com/bearfootdesign - BEARFOOT DESIGN Cherub 2648 - Comfortably Numb |
Posted By: mike ellis
Date Posted: 02 Oct 06 at 6:01pm
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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 |
Posted By: JimC
Date Posted: 02 Oct 06 at 6:44pm
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! |