Flight One-a New Kind of Performance One Design Dinghy

Flight One / C-foil system / Seahorse magazine

Basically, a boat using this concept will have a daggerboard replaced by a single "C-foil" of fairly high aspect ratio that not only generates the required lateral resistance but also generates vertical lift. The vertical lift can reduce wetted surface substantially helping planing to begin earlier and increasing top end speed. This is a more robust application of "foil assist"- already successfully proven on the International 14 and National 12 monohull dinghies as well as on Open 60 race boats like Virbec-Paprec 3 and Saffran and on numerous multihulls of all lengths and types. On an International 14 the vertical lift from the rudder foil is nominally around 95lb(of a 550lb sailing displacement-17%) whereas the C-foil can be designed to lift more than 50-60% of the boats sailing weight.
This concept is the first application of foil assist, that I am familiar with, that requires only a single retractable foil. The foil can be retracted 100% or be designed to be left partially below the hull . The foil can be moved side to side manually or be tied into to the movement of a sliding seat.
The foil can be "tuned" underway by partial retraction or by changing the angle of incidence without affecting the lateral resistance portion of the board.
I think that incorporating a foil like this with or without a small rudder "T-foil" can add a new performance dimension to single or doublehanded dinghy design.
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The following is from Seahorse Editor Andrew Hurst. Seahorse is THE magazine of sailboat performance technology: (IMOCA 60= OPEN 60)

"A key reason for the positive camber boards on IMOCA 60's and some new VOR70's is that rather than providing maximum lateral lift when heeled, by being canted outboards(bottom out dl), instead gains are taken in generating vertical lift by leaning the asymetrical foils the other way(top outboard-dl).
Similarly, the curved foils used so successfully by Guillaume Verdier on his IMOCA 60 designs.
So (yet) another new world begins."

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What is so cool about this is the recognition by the worlds premier sailing performance magazine of the importance of the developing vertical lift technology on monohull keelboats. And, as was proven and continues to be proven more and more frequently by the use of curved lifting foils on small multihulls(after having been pioneered and proven for years and years on large trimarans), the curved lifting foils on the Open 60's are perfect for numerous applications on smaller boats particularly dinghies where boats specifically designed to use this "foil assist" technology have the opportunity to carry the foiling revolution to another extraordinary step up in performance dinghy design.
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References: See http://www.boatdesign.net/forums/sailboats/dinghy-design-open-60-influence-36401-10.html post 137 is sort of an index---check it out.
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Pitures: L to R: 1) Single curved lifting foil(C-Foil) retracted in athwartship trunk for beaching, 2) C-Foil on stb tack-fully deployed, 3) V3-Verdier designed Open 60 and winner by a large margin of the Barcelona World Race-only the second Open 60 ever to use curved lifting foils, 3) V3's curved foils.

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Flight One-a New Kind of Performance One Design Dinghy/ C-Foil

Below is an updated version of the first post. The difference is that from now on* the Flight One / C-Foil concept will encompass a performance doublehanded dinghy design as well as a performance singlehander design also capable of being sailed fast with two people.These basic designs will be presented down the line along with more detailed information about the whole concept and any other designs using the C-Foil that may be conceptualized and/ or developed by others.
* thanks to Frank!
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Flight One / C-foil system :dinghy design

As part of a continuing research effort on current dinghy design I will follow on from post #2 of this thread and highlight some interesting designs as this thread progresses in an effort to learn as much as possible about what other designer/developers are thinking......
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Here is an interesting piece written by the designer of the Hartley Rebel skiff: http://www.rebelskiff.com/designers-notes/


An excerpt:

It’s not often that I get a commission to design a new high performance racing dinghy with such an unrestricted brief.

“We want a boat to be the show piece of our range; fast, challenging and at the leading edge of technology”

The recent movement from within the ISAF to investigate the possibility of a new high performance skiff for Women gave Hartley Laminates the perfect incentive to develop a truly fast and challenging boat suitable for Olympic standard women sailors.

In considering the overall parameters we determined the dominant factors were weight and overall size. We were determined to produce the lightest boat possible using state of the art, but economic, production techniques. Obviously weight is to a large extent dependent on size and we researched extensively to determine the minimum size which would support the ideal crew weight range of 120-140 Kg. in combination with other parameters such as overall righting moment, adequate rig size etc. This lead us to believe that a minimum waterline length of 4.4 meters was required if a smooth performance envelope across the wind range was to be achieved. In order to achieve this; the all up weight of the boat, hull, foils, rig, everything had to be no more than 90kg. This would amount to a considerable challenge in a mass production environment.

Length 4.5m / 14.8'
Beam Hull only 1.4m / 4.6'
Beam including racks 2.9m / 9.5'
Bare Hull weight 40kg / 88lb
All up sailing weight(not incl crew) including foils and sails 89kg / 196lb
Mast length 7.6m / 25'
Upwind SA- 196 sq.ft
--Jib area 5.7m2 / 61 sq.ft.
--Main area 12.5m2 / 135 sq.ft.
Downwind SA- 503 sq.ft.
--Gennaker area 28.5m2 / 307 sq.ft.
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NOTE: for reference material on many existing performance and daysailer dinghy designs try here: http://www.sailboatdata.com/firstpage.asp

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Flight One / C-foil system :dinghy design

Here is another new performance(borderline performance characteristics) singlehander by Keith Callaghan called the Hadron: http://www.bluelightning.co.uk/Hadron/Hadron01.shtm


Some info from Keith Callaghan:

Hadron is a new design for 2011. I have got back into racing dinghy design in the last few years, and in 2011 plan to get back into crewing Merlin Rockets - in particular MR3708 "Wicked". As part of my fitness training I am building a new singlehander design which I have developed from the same hull shape as "Wicked". Although the market is full of singlehander dinghies, the search is still on for a singlehander which will fulfill the requirements of the experienced dinghy sailer who is perhaps, like myself, getting on a bit, but who nonetheless demands high performance, and without too much pain. In other words, the boat must have impeccable handling characteristics, be comfortable to sit out and to sit in, easy to right after a capsize, and of course be fast and rewarding to sail. Just like a Merlin Rocket.

The rig is based around a standard carbon Merlin Rocket mast from Chipstow Boatyard.

Principal Dimensions:

Length over all 4.27 metres / 14'
Length on waterline 4.20 metres / 13.8'
Beam 1.95 metres / 6.4'
Hull weight 70kg / 154 lb.
Sail area 9.2 sq metres / 99sq.ft.
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More designs from Mr. Callaghan: http://www.bluelightning.co.uk/

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Flight One / C-foil system :dinghy design

Another Rebel from g-force dinghies( borderline performance characteristics) : http://www.g-forcedinghies.com/
one hull-two models:

•Produced in vinylester vacuum injection with a honeycomb core, a method previously only used in yacht building. The total hull weight is 78 kg.
•Due to this production method the hull is not just light but as well very strong and stiff. Stiffness is required to keep the boat handling easy while sailing at high speed or planing. The stiffness even remains after years and years of intense sailing!
•The hull has an extremely nice finishing comparing with PE or polyester boats.
•CE quality certificate and South African Boating Award 2006 winner in the category "non-powered trailerable craft".
•Standard equipped with a set of Pentex Mylar North Sails, mast and boom of Selden and Ronstan hardware.
The starting model "Fire" is equipped with jib and mainsail, and when the sailor is ready to go for true action the hull allows an easy adjustment of a gennaker pole and a total gennaker set to model "Radical" which can give the boat a speed of 20 knots at 15 knots true wind.

So not just a "new kid on the block" but a serious contender amongst the competition. Not just "another dinghy" but a very well over thought concept, developed by G-Force Yachts in close co-operation with International dinghy sailors.
Specifications-

"Fire" (no gennaker)
"Radical" (w gennaker)
Fire
Loa 4.323m / 14.18 ft.
Beam 1.48m / 4.85'
Weight(?) 78kg / 172lb
Upwind SA 8.65 sq.m. / 93 sq.ft.
Downwind SA 11.07 sq.m. / 119sq.ft.
--gennaker-2.42 sq.m. / 26 sq.ft.

 

Flight One / C-foil system inghy Design

For anyone interested in high performance-or just improved performance-in small boat design there is interesting information here: http://www.boatdesign.net/forums/multihulls/mayfly-class-catamaran-fischer-39616.html
Martin Fischer has done a very interesting design where he utilizes "shared lift" pioneered by Bill Roberts in multihulls-and among others Thomas Jundt in monohulls. He combines it in a unique way with curved lifting daggerboards and "J"- type rudder foils.
A boat like "Flight One" using a C-Foil could be designed in a similar way allowing the daggerboard to be further forward than on a "normal" dinghy increasing the distance between the lift of the daggerboard and the lift(up or down) of the rudder increasing pitch resistance. My concept has always been to increase the "foil assist" lift from the 17% on a I-14 upwind in 10 knots of wind to a figure between 50 and 70 % of all up weight in similar conditions for a design using the C-Foil.
Fischers cat in 10 knots of wind lifts 40% of the total weight.
So I think, for a monohull, the higher percentage of lift is an appropriate target along with the use of a variation of "shared lift".

 

Flight One / C-foil system

Another interesting tidbit: in the multihull forum here is a story,by catsketcher(Phil Thomson) of his experience of sailing an ORMA tri-the boats that perfected curved lifting foils. He mentions that those foils can be adjusted under load which is pretty incredible. Also, the guys that sail the NACRA 20 say that their curved foils are pretty easily adjustable.
Just goes to show that a properly designed and engineered C-foil should be easy to handle in tacks and at other times that adjustment is necessary.

 

Flight One-a New Kind of Performance One Design Dinghy/ C-Foil

I've had some time to consider this concept some more and the most "serious"
negative I've been able to come up with is that the boat has to be wider at the waterline than is ideal in order to be able to fit the right size foil into the boat. That may or may not be a problem-I need to do some detailed design work before I'll understand that better.
The positives are pretty signifcant so far so we'll see.
What do you think, Mal?
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Development Target: One of the most significant developments in foiler design may be a curved foil that uses a flap on the portion that lifts vertically(a basically straight section at the end of the foil,probably) that can be connected to a wand surface sensor rather than a Hobie trifoiler "feeler". The aspect ratio advantages of the curved foil(Greg Ketterman) would then be able to be easily adaptable to a retracting curved foil instead of using the "feeler" surface sensors on the non retractable, all moving Hobie Trifoiler foils. If anyone comes up with a good idea how to do it I will try it on the model in this thread: http://www.boatdesign.net/forums/mu...lf-righting-trimaran-test-model-36058-10.html
The results may be applicable to any boat using the right kind of curved foil.

 

Hi, Doug.

Was just thinking of your concept.

It occurred to me that you will need two sets of pinch rollers to deploy the foil. One on the port side and one on the starboard. This is because so much of the foil will be deployed that little will be left in the boat. And what little is left will be on one side or the other.

You will also need a lock mechanism to keep the foil from being pushed back into the boat by its lift.

Come to think about locking mechanisms, I just thought of one to lock a swing keel down in more than one position. Had my boat had such a device, it might not have continued its capsize. There was a lock down position, but it was only with the keel all the way down. As the boat developed significant weather helm with the keel no where near vertical, my guess is that it was intended as a heave too device for survival conditions.

Back to Flight One. Have you considered a more conventional foil arrangement with the lifting foil being on the very bottom. The vertical portion could act as a dagger board, and since the lifting foil is not supposed to carry the entire weight of the boat, the vertical portion will stay immersed at act as a dagger board.

This would be much simpler than a foiler moth and the hull could be designed as a Hickman sea sled with a bit of keel, just a few inches, to project lower than the retracted lifting foil. Just a thought.

 

Flight One / C-foil system

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Thanks, Sharpii!-appreciate your thinking about this. Haven't given much thought to a locking system yet but I'll need some sort of system.
I've considered different foil systems but none with effective aspect ratio advantage of the curved foil as explained to me by Greg Ketterman and posted in the "Dinghy Design: Open 60 Influence " thread( http://www.boatdesign.net/forums/sailboats/dinghy-design-open-60-influence-36401-4.html post 54). The advantages of a curved foil, besides effective aspect ratio, include independent adjustment of the angle of incidence of the lifting portion or lateral resistance portion without interfereing with the other, ease of configuring for the conditions, and ease of retraction( or leaving two tips down as mentioned earlier).
If you get a chance, think about a system that allows a flap controlled by a wand surface sensor on a curved foil w/o interfereing with the other advantages of a curved foil-the "Development Target" in my last post. Right up your alley maybe-I'm having a mental block with it-at least, it's a pretty tough nut to crack.

 

Flight One / C-foil system

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I've found that there was a flap actuator for model airplanes that has a movement close to what I'm looking for. It was around 15 years ago or so and allowed a pushrod running spanwise in the wing to actuate a flap. Anybody remember this thing?
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C foil system

This is a potentially new foil and rudder system with applications probably limited to trimarans(at least for the main foils). But this may stimulate some thinking in the Great Quest to Eliminate the T-foil-at least in some areas. See post 145 here for more detail: http://www.boatdesign.net/forums/mu...-trimaran-test-model-36058-10.html#post490418

 

I'm reminded of when I visited a friend's home during high school. His dad is a multiple doctorate pure math professor at Waterloo who worked at Los Alamos, Princeton and has published more papers than I could count. I saw a page or two of his work and picked it up to see if I could understand it. I stared and stared. His dad reached over and turned the paper 180 degrees and said, "Now it is upright". I still saw nothing recognizable.

--
CutOnce

 

C Foil System

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Well, sorry about that-I thought I explained it fairly well in the other thread. I'd be glad to answer any questions you may have.

 

Flight One / C-foil system

The major design aspect of the Flight one concept is the the single curved lifting foil used for "foil assist"-and not requiring any kind of altitude control. However, in versions of the boat where a lot of the boats weight is expected to be lifted by the main foil it will probably be advantageous to use a lifting foil on the rudder -perhaps with controllable angle of incidence.
In some boats that use rudder foil lift(up or down) for "foil assist" without any forward foil, "T"-foils have been used.
But it appears that a "J" foil would be significantly more efficient so the rudder system in the rough sketch below may be a good solution except for the fact, that as presently conceived, it would require two rudders-one retracted with every tack. I'm not entirely convinced that such a system, with its weight penalty, would be enough better than the "T"-foil to warrant its use on a foil assist monohull. There are monohull dinghies and scows that use dual rudders so I'm not ruling it out. More detailed research, which I am continuing, will allow a more informed comparative decision to be made-but it is an interesting possibility.
The system sketched previously(and again below) shows two rudders on one stock arranged so that one can pivot at a time. Each rudder would be sightly off the center line
and the whole stock could be pivoted to change the angle of incidence of the foil(both simultaneously). There would be one tiller and probably one extension tiller. It would not be as heavy as some dual rudder installations.
The simplest explanation of the advantage is that this type of rudder always has high and low pressure on only one side resulting in a better effective aspect ratio whereas a t-foil has high and low pressure on the same side(one side at a time) much of the time, most particularly upwind.
More on this here: post 54 http://www.boatdesign.net/forums/sailboats/dinghy-design-open-60-influence-36401-4.html See the link in the post.

Rough Sketch: Double "J" foil rudder- click on image- In this particular application the foil tip would always be pointed to windward with the rudders swapped out between tacks. The main advantage is upwind-as I understand it now.