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T foil rudders

Started by ifoxwell, 10 Mar 2010, 12:24

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ifoxwell

Quick question
I think I'm right in saying that the two current favourite boats in build use a T foil rudder...
If so have these been retrofitted successfully to older boats yet or does the whole hull / foil interaction demand a new boat!
Cheers
Ian

Tim Gatti

Ian - see separate earlier thread.  Dare Barry has successfully retrofitted one to his boat. 
Given that DCB and Paradigm hulls were designed with the use of a T foil in mind, I believe they produce a stern wave of the most appropriate form and position for the foil to make best advantage of the hydrodynamics to produce optimal lift, then I presume there will be limits as to how (cost) effective the fitting of a T-foil to other, older hull shapes would be.
Unless you are an expert in foil design and construction, the costs of having one made as an experiment look a trifle unattractive.  (eg cost of t-foil rudder and fittings = total cost of a Baggy + combi, cover and 2 suits sails)
But - you pays your money and takes your choice.  Perhaps Dare and others would like to comment?
Tim

ifoxwell


MikeDay

#3
At the dinghy show, Steve Norbury showed me the winged rudder and very neat fitting that he has engineered for retro-fitting to his Foolish, so it'll be interesting to see what difference that makes.  I went round the show with Bim Daser who said that he thought a Foolish or Numinous would need bigger wings than a DCB because of the shape of their particular transoms.  It made sense when he was explaining it to me but I'm not sure on reflection that I understand.
 
Mike D
N353* 

Tim Gatti

If you don't understand it Mike - what chance have we mere mortals got?

darebarry

Ian. Retro-fitting of a foiling rudder is very simple. My rudder has a ss/rod that fixes the rudder to the transom using an upper and lower gudgeon.ie. The basic stock fits to the boat in a manner similar to a Winder stock. Than only leaves controles to be fitted to suit the driver. There is a cost in buying this bit of kit, but then at one time carbon masts  had the same problem. I can E Mail you a pic if that would help
Cheers Dare N3521.

ifoxwell

Hi Dare
It would be good to see what you did... I guess what I'm really asking though is does it work... is it worth the effort.
Cheers
Ian

darebarry

Ian, having a problem with your E Mail ad. Can you send me E Mail so I can reply.
Cheers Dare

ifoxwell

Thanks for the pictures Dare. It does look good and if I could find a cheap, easy way of making one that even I could manage then I'd have a go, just for the pose. 

Another spin then on the same question then... Is there a time when those that have a winged rudder dont use it... will everyone need two rudders in the futture?

Ian

Antony (Guest)

Ian,
The simple answer is that the DCB does not really work without the wings, and has been proven to work on open water in light weather with them and still go well.  The 'Paradigm' is designed to be able to pull them up out of the water when it is really light, although it is not clear to me whether the owners will continue to do so they have made it possible to do with one blade (it is a daggerboard style rudder and the wings are quite high up it).
I personally would guess that with older designs you are more likely to want to revert to a normal rudder in light weather or restricted water, but i have never used one and do not indeed to in the near future.
Other will, doubtless, have other opinions and i am certainly an observer rather than an expert.
Antony
N3348 (it is possible it is available to borrow for Burton Wk if you are interested.. it is a D8)

muddled (Guest)

In a recent interview the new I14 world champion stated that he believed he would need different wings for different venues and conditions.  He also pointed out that he didn’t yet know what those wings would look like.  If he doesn’t know few people here do.

ifoxwell

That's perhaps a fair point however the affect of wings on a fast apparent wind boat must be different from the affect on a slower boat that is predominantly sailed in displacement mode.
And as the 12 fleet are leading the way in this respect i cant think of any one better to ask :)
Ian

ifoxwell

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Quote from: Antony (Guest)
Antony
N3348 (it is possible it is available to borrow for Burton Wk if you are interested.. it is a D8)

Thanks for the offer Anthony but we are hoping to have our own boat by then... and if we dont i'm not sure we would be that comfortable borrowing some one elses when we dont really have much experiance in the class.
Thanks for the offer though, its much appreciated.
Ian

ifoxwell

#13
I thought I would rekindle this thread with another question.
Since the original posting we have bought Bicycle clips, a baggy trousers, and are loving her.
As part of the deal I was given a second old rudder blade and stock... and as we are never going to use it I thought i might have a go at building a T foil rudder for her. More for the experience than any great expectations of improving her performance but it raises a couple of questions.
What kind of wing profile/dimensions is being used on the current designs (no point in trying to re-invent the wheel if some one can point me in the right direction)
And what sort of wing position/angle should I be aiming at?
Cheers
Ian
3162 Bicycle clips

Jeremy C

Ian,

Graham Camm has built his own t-foil for his DCB as he ordered the hull only (also built his own trim-tab C/B) contact him via the class handbook.
Steve Norbury N3516 has a very sweet system for attaching his t-foil to his feeling foolish. It is an interpretation of the DCB system but works off the top pintle instead of the bottom. If I see him at the club I'll try and get some pictures of it.
Trick Cyclist-3444<br />In the pink-3408<br />Kifi-2431- under restoration<br />Flying Saucer 1277 (joint owner)<br />and now Bart 3455 too (sigh!)