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A third foil |
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x1testpilot
Posting king Joined: 11 Feb 11 Location: Ealing Online Status: Offline Posts: 175 |
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Topic: A third foil Posted: 11 Apr 12 at 10:17am |
Glen Truswell’s revolutionary hydrofoil support strut/prep foil system looks like a good idea to me, it would keep the rudder simple (cheaper) again.
See http://www.yachtsandyachting.com/news/162491/International-14-Easter-Tray-at-Itchenor |
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Chris Turner
Posting king Joined: 09 Jul 06 Location: United Kingdom Online Status: Offline Posts: 142 |
Post Options Quote Reply Posted: 11 Apr 12 at 10:29am |
It was tried a number of years ago by one of the Aussie teams.
At that time it was deemed against class rules, I wonder if that has now changed?
I have not looked at a set of 14 rules for a while now, but do get the email updates from time to time.
May be there has been a change of chief measurer that has a different opinion?
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x1testpilot
Posting king Joined: 11 Feb 11 Location: Ealing Online Status: Offline Posts: 175 |
Post Options Quote Reply Posted: 11 Apr 12 at 10:47am |
Funny things class rules! I'd have thought it illegal, but 14's are pretty open to change and this one doesent look outrageous and looks potentially cost saving so could be popular. I didn't know it had been tried before - did it work?
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JimC
Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6649 |
Post Options Quote Reply Posted: 11 Apr 12 at 10:48am |
I don't see how it works. Any explanation?
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I luv Wight
Really should get out more Joined: 28 Jan 05 Location: United Kingdom Online Status: Offline Posts: 628 |
Post Options Quote Reply Posted: 11 Apr 12 at 11:03am |
I guess that the rudder is without a horizontal foil ( I think the number of lifting foils and max area are limited to one and x?m˛ ), so this system separates lift and steering, possibly making it easier to sail.
Downsides must be more drag on the strut, and wanting to go in a straight line - this might be useful though. |
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Medway Maniac
Really should get out more Joined: 13 May 05 Location: United Kingdom Online Status: Offline Posts: 2788 |
Post Options Quote Reply Posted: 11 Apr 12 at 11:06am |
Pretty much what Porsche were up to in 1969, in reverse, I'd have thought:
Energy recovery or downforce (OK lift or downforce for the 14 for the 14), depending on the angle, along with some longitudinal stabilisation (like a skeg). Total nightmare with any weed about, I'd have thought. Plus, I'd have thought the foil would be more effective for lift if mounted further aft (like on the rudder) where the flow is more upward. Bet the Porsche boys would have stuck the wing out behind the car, structures and regs permitting.
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furtive
Posting king Joined: 30 Mar 05 Online Status: Offline Posts: 188 |
Post Options Quote Reply Posted: 11 Apr 12 at 11:07am |
It looks like it's separating the two functions of a "conventional" 14 rudder - the additional foil shown in that photo supports the horizontal hydrofoil and controls fore/aft trim, then a normal (non- T-foil) rudder in the normal position is for steering only.
No idea if that's an accurate summary, or whether it will work, but it's interesting...
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JimC
Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6649 |
Post Options Quote Reply Posted: 11 Apr 12 at 11:07am |
Oh right, so the lifting foil is on a non rotating skeg (under the boat? On the gantry?) and the rudder is running in its wake? Hmm. Better not be a laminar flow on that rudder section then! I suspect the further forward you have the lifting foil the better (to an extent anyway). It would be good to be able to have the foil lift ahead of the crew weight.
Although the rudder might be cheaper I rather doubt that the total expenditure would be less... And three foils to pull up on a dodgy return to shore might up the adrenalin level a bit! Edited by JimC - 11 Apr 12 at 11:11am |
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Medway Maniac
Really should get out more Joined: 13 May 05 Location: United Kingdom Online Status: Offline Posts: 2788 |
Post Options Quote Reply Posted: 11 Apr 12 at 11:13am |
That's true, but then you'd be better off with it on the c'board, I'd have thought. But it's probably all down to rules. |
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x1testpilot
Posting king Joined: 11 Feb 11 Location: Ealing Online Status: Offline Posts: 175 |
Post Options Quote Reply Posted: 11 Apr 12 at 11:29am |
I would think cost less as rudder does not need to have heavy engineered bearing/tilting mechanism and without horizontal foils would be a lot easier to make and easier to deal with especially launching etc. Also weed or breakage could(?) be dealt with separately from the rudder (It looks as if it would (just) lift clear of the water (?) You could also leave ashore if it was really weedy!
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