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Kickup T foil rudder #106508
05/09/07 06:43 AM
05/09/07 06:43 AM
Joined: Aug 2002
Posts: 545
Brighton, UK
grob Offline OP
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Brighton, UK
What do people think of this kickup T foil rudder setup?
[Linked Image]
The system is very simple. The T-foil is attached to the bottom of the main rudder blade, and is allowed to pivot freely. Referring to the sectioned plot below, the T-foil is also attached to the rudder box via a line that runs through the rudder blade. When the rudder blade is in the vertical deployed position the line pulls the T-foil tight against the bottom of the rudder blade holding it in a horizontal sailing position. When the rudder blade is released to swing to the horizontal position the T-foil is also automatically released.
[Linked Image]
Although this is currently shown on a Dotan stock (as this is what I use) it can be retrofitted to any existing kickup rudder system.

Gareth

-- Have You Seen This? --
Re: Kickup T foil rudder [Re: grob] #106509
05/09/07 07:34 AM
05/09/07 07:34 AM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
Carpal Tunnel
Wouter  Offline
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Not enough distance difference as a result of the pivoting to pull the T-foil in tight.

The radius from the fullcrum to the point where the line enteres the rudder boards is too short.

Maybe have a pully on the stern and a clear on the rearbeam so the skipper can activate and deactivate the T-foil ? (an idea I had for the F12) But still have the problem of the line stretching resulting is a flapping T-foil possibly damaging the rudder board itself.

Wouter

Last edited by Wouter; 05/09/07 07:37 AM.

Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: Kickup T foil rudder [Re: grob] #106510
05/09/07 07:46 AM
05/09/07 07:46 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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Interesting thought. I would first be concerned about flutter of the foil if it kicks up while the boat is moving at any decent speed...that is, unless you built in some imbalance stability into the foil - but that would result in undesirable drag during normal attitude. I know first hand that control surface flutter can be violent and result in the death of a model airplane!

The geometry between the pivots and the line seems to be a bit off - but that might actually take care of the potential for flutter if it can be arranged put the foil at a slight bit of a "down plane" attitude when it is released.


Jake Kohl
Re: Kickup T foil rudder [Re: Jake] #106511
05/09/07 08:04 AM
05/09/07 08:04 AM
Joined: Jan 2005
Posts: 6,049
Sebring, Florida.
Timbo Offline
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Why not just improve the lifting mechanisim on the present casette type T foil rudders? Personaly I like the idea of only having half the rudder, or less, down when coming in to or departing the beach. You will still have a lighter helm than with a kicked up rudder, which can be hard to steer in big wind and waves. And it would seem the casette type system would be lighter, less moving parts to break, etc.

Could someone who uses the present T foil rudders please post a close up picture of the headstock and the rudder in both the up and down possition, and tell us how it works? Thanks.

Last edited by Timbo; 05/09/07 08:07 AM.

Blade F16
#777
Re: Kickup T foil rudder [Re: grob] #106512
05/09/07 08:12 AM
05/09/07 08:12 AM
Joined: Jan 2007
Posts: 71
Lake Norman, NC
Special_Treat_P182 Offline
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Lake Norman, NC
I'm curious... Why foil the rudder? We're not talking about foiling the entire boat to raise it out of the water, just the rudder. What does creating lift on the rudder accomplish other than raising the transom a bit? I don't see it as improving helm performance or balance. So if you want to raise the stern, why not simply move crew forward? At least on my Prindle, if the crew is near the front crossbar, I can raise the stern quite a bit.

It just seems as though it's a complicated design which introduces another point of failure (and expensive failure at that) for very little gain or at least a gain that be gotten from simply repositioning the crew on the boat.

Re: Kickup T foil rudder [Re: Special_Treat_P182] #106513
05/09/07 08:24 AM
05/09/07 08:24 AM
Joined: May 2002
Posts: 3,114
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MauganN20 Offline
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Its supposed to keep boats with not enough bouyancy up front from pitchpoling.

As the muscle car guys say, in my opinion,

"There's no replacement for displacement (in the bows)"

Re: Kickup T foil rudder [Re: MauganN20] #106514
05/09/07 08:30 AM
05/09/07 08:30 AM
Joined: Jan 2007
Posts: 71
Lake Norman, NC
Special_Treat_P182 Offline
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So again, is this an overly-complicated solution to a rare problem? I know of Hobie and Prindle 16's that were more prone to pitchpoling, but most modern cats aren't. I installed the cheap anti-pitchpoling foils on the bows of my old Hobie-16 and they seemed to work very well for a hundred bucks. Afer that pitchpoling the 16 required a serious mistake on my part.

Re: Kickup T foil rudder [Re: grob] #106515
05/09/07 08:48 AM
05/09/07 08:48 AM
Joined: Nov 2003
Posts: 99
Chicago, IL
Krisu13 Offline
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Chicago, IL
If you are not going to do any backward sailing - just eliminate the line going through rudder blade.


I20
Re: Kickup T foil rudder [Re: Special_Treat_P182] #106516
05/09/07 08:55 AM
05/09/07 08:55 AM
Joined: Jan 2005
Posts: 6,049
Sebring, Florida.
Timbo Offline
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The guys who have them like them, I think the Stealth (F16 type) has them, they say they really smooth out the ride and keep you from nose diving in a windy gibe. The Jurry is still out on wether they are "faster" or not, but swimming is slow.


Blade F16
#777
Re: Kickup T foil rudder [Re: Timbo] #106517
05/09/07 08:55 AM
05/09/07 08:55 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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Quote
Why not just improve the lifting mechanisim on the present casette type T foil rudders? Personaly I like the idea of only having half the rudder, or less, down when coming in to or departing the beach. You will still have a lighter helm than with a kicked up rudder, which can be hard to steer in big wind and waves. And it would seem the casette type system would be lighter, less moving parts to break, etc.

Could someone who uses the present T foil rudders please post a close up picture of the headstock and the rudder in both the up and down possition, and tell us how it works? Thanks.


I hadn't thought of that - boy that would be really nice.


Jake Kohl
Re: Kickup T foil rudder [Re: Jake] #106518
05/09/07 09:11 AM
05/09/07 09:11 AM
Joined: Feb 2005
Posts: 1,382
Essex, UK
Jalani Offline
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Jalani  Offline
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Essex, UK
The German built Topcat uses a cassette system which is retained by stiff bungee so that if a down rudder hits an obstruction the rudder (and stock) kicks up. I've thought of engineering something similar for the Stealth.....
[Linked Image]

Attached Files
107518-topcatstock.jpg (34 downloads)

John Alani
___________
Stealth F16s GBR527 and GBR538
Re: Kickup T foil rudder [Re: Jalani] #106519
05/09/07 09:15 AM
05/09/07 09:15 AM
Joined: Jan 2005
Posts: 6,049
Sebring, Florida.
Timbo Offline
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Thanks for the picture John, now, tell us about the ride with the T foils. (I know this was covered a year or so ago, any updates?)


Blade F16
#777
Re: Kickup T foil rudder [Re: Timbo] #106520
05/09/07 09:20 AM
05/09/07 09:20 AM
Joined: Feb 2005
Posts: 1,382
Essex, UK
Jalani Offline
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Essex, UK
The ride has been discussed at length, as you say, having sailed with them, I couldn't now imagine sailing without them! <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Only update is the new Stealth (2006/7) T-foils are a fantastic improvement on the older ones. Small, lighter, stronger and much better engineered. Less drag IMO, but just as effective as the older, larger foils. John_P has done a really good job!


John Alani
___________
Stealth F16s GBR527 and GBR538
Re: Kickup T foil rudder [Re: Jalani] #106521
05/09/07 09:35 AM
05/09/07 09:35 AM
Joined: Jan 2005
Posts: 6,049
Sebring, Florida.
Timbo Offline
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If I wanted to buy a pair to put on a US Blade, what would that cost, for the new ones? Rudders, heads, tillers and mounts?


Blade F16
#777
Re: Kickup T foil rudder [Re: Timbo] #106522
05/09/07 11:45 AM
05/09/07 11:45 AM
Joined: Feb 2005
Posts: 1,382
Essex, UK
Jalani Offline
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Your best bet Tim would be to cantact John Pierce - either PM him (john p) or through the website: http://www.stealthmarine.co.uk


John Alani
___________
Stealth F16s GBR527 and GBR538
Re: Kickup T foil rudder [Re: Timbo] #106523
05/09/07 05:55 PM
05/09/07 05:55 PM
Joined: Jul 2006
Posts: 1,147
Bay of Islands, NZ
W
warbird Offline
old hand
warbird  Offline
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Bay of Islands, NZ
I am in this camp. I used casset type a lot as a young mono sailor and always liked them more than flip up. Once you have the travelling tuned they are fast easy and can quickly be set at several heights without losing stearage. Extra moving parts creates possiblity for gear failure. But nice images.
BTW don't hit anything if they don't flip up! (we don't have big jellies here)

Re: Kickup T foil rudder [Re: warbird] #106524
05/10/07 04:55 AM
05/10/07 04:55 AM
Joined: Apr 2006
Posts: 37
L
Laruffa Offline
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Laruffa  Offline
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Hi everyone,
Would like to ask you a question, after sailing 49ers I always ask the question why not!! rudders in a box system?? they have some good points 1)when you need to sail into or out of a beach with any seaway they would work well if you could just left them up to miss the bottom and still steer! 2)packing the boat for transport all you need to do is take them out and pack them into a bag like the centre boards! 3) they would never kick up under load or sailing in waters with things like jellyfish! 4)if anything fouled them like seawead you could still steer while lifting them free! 5)in conditions like high winds with flat waters you could lift them to reduce drag?? [color:"red"] [/color] disadvantages? 1)hitting a object or the bottom in shallow waters?? BUT would it be cover by the centre boards???? whats your thoughts!!!! Love allways MarkXX <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

Re: Kickup T foil rudder [Re: Laruffa] #106525
05/10/07 05:08 AM
05/10/07 05:08 AM
Joined: May 2003
Posts: 4,451
West coast of Norway
Rolf_Nilsen Offline
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I like them, and think kick-up rudders are a leftover from the rotating centerboard days. Today the daggerboard (unless you have skegs) will hit the ground before the rudders, so you will ruin your day anyway.

Re: Kickup T foil rudder [Re: Laruffa] #106526
05/10/07 07:28 AM
05/10/07 07:28 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
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South Carolina
Quote
Hi everyone,
Would like to ask you a question, after sailing 49ers I always ask the question why not!! rudders in a box system?? they have some good points 1)when you need to sail into or out of a beach with any seaway they would work well if you could just left them up to miss the bottom and still steer! 2)packing the boat for transport all you need to do is take them out and pack them into a bag like the centre boards! 3) they would never kick up under load or sailing in waters with things like jellyfish! 4)if anything fouled them like seawead you could still steer while lifting them free! 5)in conditions like high winds with flat waters you could lift them to reduce drag?? [color:"red"] [/color] disadvantages? 1)hitting a object or the bottom in shallow waters?? BUT would it be cover by the centre boards???? whats your thoughts!!!! Love allways MarkXX <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />


I too like the idea of a cassette style rudder. Big jellies are not usually a risk to the structure of the boat but things like stumps or perhaps a rock outcropping might be. However, you could still have some sort of breakaway "fuse" at the gudgeon in the event you really did hit something hard.


Jake Kohl
Re: Kickup T foil rudder [Re: grob] #106527
05/10/07 09:08 AM
05/10/07 09:08 AM
Joined: Jun 2001
Posts: 1,449
P
phill Offline
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Gareth,
Intersting concept.
Obviously it would need some work to refine.
Got me thinking could even replace the line with thin flat rod down the centre of the rudder.
When building the rudder a slot could be made down the centre to accomodate the rod.
Now if you can control the rod from the top you would also have the ability to adjust the angle of the
T foil while sailing.

Regards,
Phill


I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!

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