How’s this for quick

   If the dagger is asymmetrical then itll pull the boat sideways - like a gybing dagger board but with no control over it. The actual board itself "shouldnt" cause more drag than a turbulating board as the flows laminar. But dragging a 49er upwind sideways...................... thats where the drag may come in!
I just have my foils clean smooth and fair - does the job and we just get the wind as it 'whistles' through the rigging downwind, the higher the pitch the more apparent we are building!  

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andy_cherub Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 16 Mar 05 Location: United Kingdom Online Status: Offline Posts: 768	Post Options Post Reply Quote andy_cherub Report Post Quote Reply Topic: How’s this for quick Posted: 13 Jan 08 at 8:42am
	If the dagger is asymmetrical then itll pull the boat sideways - like a gybing dagger board but with no control over it. The actual board itself "shouldnt" cause more drag than a turbulating board as the flows laminar. But dragging a 49er upwind sideways...................... thats where the drag may come in! I just have my foils clean smooth and fair - does the job and we just get the wind as it 'whistles' through the rigging downwind, the higher the pitch the more apparent we are building!
	-12ft skiff, Team 'CST Composites' -Many thanks goes out to all of my sponsors. Ignore my user name, my views are of a 12ft skiff

Skiffman Send Private Message Find Member's Posts Visit Member's Homepage Far too distracted from work Joined: 27 May 04 Location: United Kingdom Online Status: Offline Posts: 291	Post Options Post Reply Quote Skiffman Report Post Quote Reply Posted: 13 Jan 08 at 8:43am
	i meant upwind not downwind... the carbon rig will be available to buy in the UK in September, remember the new moulds are not CNC. They are making a master plug that is CNC and then making the moulds off that. What makes everyone think that the new boats will be faster... the new foils are slower in most conditions to a faired set of old foils (which most people did). They will make it so in the first year you can use both rigs but if you use a new rig you have to carry correctors (3.5kg) and then in the second year and onwards you have to use the new rig in Gold fleet. The new wings are not carbon and are being changed because it costs so much to make the old wings. I can not wait for the new rig especialy as our first worlds with them is going to be in Garda! p.s ours do not hum and we do not make the back edge asymmetrical but they do in finns Edited by Skiffman
	49er GBR5 teamfletcherandsign.co.uk Team Fletcher and Sign campaign site

Chris Bridges Send Private Message Find Member's Posts Really should get out more Joined: 14 Nov 07 Location: United Kingdom Online Status: Offline Posts: 699	Post Options Post Reply Quote Chris Bridges Report Post Quote Reply Posted: 13 Jan 08 at 9:23am
	Do oyu know when they are planning on replacing the wings and if they are going to phase them in like the rig? Its alright for some who have plenty of sponsors .
	49er GBR735 (for sale) - Rutland SC

JimC Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6662	Post Options Post Reply Quote JimC Report Post Quote Reply Posted: 13 Jan 08 at 9:24am
	This is a paper with some realworld research on singing foils. The speed ranges and construction materials are of course quite different. http://docs.hydrofoils.org/hiper.pdf Its interesting that they don't seem to mention drag being caused by foils singing.

andy_cherub Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 16 Mar 05 Location: United Kingdom Online Status: Offline Posts: 768	Post Options Post Reply Quote andy_cherub Report Post Quote Reply Posted: 13 Jan 08 at 9:35am
	Jim, firstly those papers refer to hydrofoils. The singing from a hydrofoil vs the hum from a daggerboard are quite different. It even shows the vorticies from the foil! & vorticies = drag (ill run a hydro stats on different foils and get figures for a faired vs non faired board ) Where are these papers from? I tent to ignore non RINA based findings as ive come across so many which are just so wrong its funny!
	-12ft skiff, Team 'CST Composites' -Many thanks goes out to all of my sponsors. Ignore my user name, my views are of a 12ft skiff