Little America's Cup UK 2013

Hydros

More from Team Hydros including the first public picture of any C Class boat foiling! This boat is using the same three foil AC configuration they tested on the Nacra F20c:
http://www.hydros.ch/actualites/234-premier-vol-sensationnel-pour-le-class-c-hydros

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Reported speed is: 21 knots in an 8 knot wind!! http://abcclass.tumblr.com/

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Hydros

More from Team Hydros-foil system illustrated:
http://www.youtube.com/watch?v=JxIibEc-ng4

 

Lac 2013

Canadian boat flying--Magnus and Fred--UPDATE new pix 7/5/13
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Lac 2013

Some have noticed what appears to be a leading edge slat on the Canadian wing -here is commentary about that from SA:

See picture below:


Well a slat is not necessarily that expensive area wise... Certainly if I was to design another C-Class (I was involved with Invictus for the 2010 campaign) I would look very closely at slats as one of the key area of development on the wing side.

To put the theory simply: the wing is very much L/D driven upwind... so you need to minimise drag as much as possible... If you retract the slats you have a nice clean wing... and you reduce the area. Because it has less area for the same span, you increase the aspect ratio and reduce induced drag... The loss of area upwind is not that dramatic... Actually if you look at the Cogito style element 2 design, you will probably find that upwind it has an ever so slightly smaller area (Steve maybe you can confirm that).

When it gets to downwind speed, on the other hand, you are very much max lift driven... So maximum area is a must. You are not so worried about drag then... Using a slat will drastically increase your max lift... In simple terms, a slat allows to bring more energy to the airflow at high angles of attack, keeping the flow attached to the wing much longer and reaching higher angles of attack before stall... So you generate much more lift.

Next time you fly anywhere, look at the wing at landing, in full landing configuration, slats are extended for the very same reason. And if you want to brush up on the theory behind all this, look at Abbott & Von Doenhoff.

I don't have the numbers handy to prove that this has a clear benefit for a C-Class wing but it is very likely! It is very heavily depending on the implementation you choose. From the pictures that have been released, it seems FYH has both slats out (port and starboard) at the same time. I guess to simplify the controls... I would bet that they can retract them for upwind sailing though.

All I can say is well done to the Canadian design team! You guys have outdone yourselves again!
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UPDATE from Magnus:

The slats are retractable on each side to a very fair surface. Lift coeficient goes from 2.4 to 3.1. This is a big deal!


Click on picture to see probable slat clearly--

 

I've drawn sketches of fold away slats, leading and trailing (who hasn't thought of this?) but my design and building skills are too low to achieve this in reality; lack of large finance and increase of weight also played a part.
But this was achieved with beautiful skill and craftsmanship on the French Otip C Class, an asymmetric inclining "windmill" wing in cross section - which provides even more lift, lessened drag than a symmetrical design. Unfortunately the boat rounded up in stronger winds and was damaged - but there was a direction that is still worth exploring.

 

Twin boards

Found on the C Class thread on SA, this is a picture of a cat from years ago with one straight board and on angled board in each hull similar but not identical to the Canadian "...Hands".

click for bigger view-

 

LAC 2013-Hands

Picture below posted on SA by blunted-shows the elements of their new wing:

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Lac 2013

From Scuttlebutt Europe today:

Team Hydros Wins Formula 18 World Championship

Billy Besson and Jeremie Lagarrigue have just won the Formula 18 World Championship in Grossetto, Italy. This is a good omen, about 2 months away from the season's main objective: The Little America's Cup, International C-Class Catamaran Championship, which will take place in Falmouth (UK) next September.

Billy Besson and Jeremie Lagarrigue, competing for Team Hydros, gained a resounding victory at the Formula 18 World Championship, in front of no less than 184 opponents representing the Formula 18 world elite. Bastiaan Tentij and Mischa Heemskerk, also competing for Team Hydros, and who will also be representing Switzerland in Falmouth in September for the Little America's Cup, finished rank 22 after sailing in the leading group for the main part of the race.

Both crews - Jeremie Lagarrigue & Billy Besson and Bastiaan Tentij & Mischa Heemskerk, participated in this championship in order to train for the Little America's Cup which they will race defending the Swiss flag.

Supported by the private bank Lombard Odier & Cie, Team Hydros is a scientific research center applied to sailing, tackling 3 challenges: Hydro Cup (participation in the C Class Catamaran World Championship), Hydro Contest (Academic Contest), and Hydro Speed Tour (Speed Record Contest).

The technological adventure of l'Hydroptere and its record-breaking exploits have been made possible by the support pledged since 2005 by Thierry Lombard, Managing Partner of the firm of private bankers Lombard Odier & Cie, whose foundation year - 1796 - is displayed on the craft's mainsail. -- Bernard Schopfer
www.f18-international.org
www.lombardodier.com

 

Lac 2013

Canadian C Class flying! Notice the fences on the rudders and the weird kink in the lee board just under the lee hull. Look carefully under the windward hull and you'll see the lifting part of the foil..... Fantastic!
Picture Meredith Block/SA----Click, expand and click:

 

Franck Cammas has launched the new C class catamaran and taken it out for the first sail:

http://youtu.be/ausTKd-Dxhs

 

Lac 2013

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Thanks, Corley! Looks like it has the right equipment.....

 

Here's another foiling "C" this time it's Camma's. Photo from Course au Large.

 

That's a terrific photo, because it suggests that two guys can get the boat up on
foils without a huge fight.

 

I believe the C class rules allow the use of lifting surfaces on the rudders for pitch control. This is much simpler and more effective than controlling pitch by raking the main boards as the AC72's are forced to do by their rules.

 

Lac 2013

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The Rave and Osprey mutifoiler's can sail w/o rudder AOI control. The rudder foil seldom needs to be adjusted and responds automatically to provide vertical lift at takeoff and downforce at "X" speed.
Most Moths use a twist grip to control rudderfoil angle of incidence.
The AC boats rake the mainfoils to control the angle of incidence of the mainfoil and therefore vertical lift -not pitch. The rudder foil is a trailing foil and automatically controls pitch as on the Rave and Osprey.
However, it would be much safer on the 72's to have controllable rudder foils that work with simultaneous control of the main foils. Against the rules and would require more hydraulic capability, unfortunately.
There are no restrictions on C Class foils in terms of control(except beam restrictions).