Apr 23, 2015

The Quest for the Full Foiling A-Class: Arno Terra's 'Flying Carpet'

Arno Terra's Flying Carpet concept, Cads by MV / Catsailignews.com . Click image for actual size, ---
I've been exchanging mails and technical chats with Arno since the early  CSN & then DNA days where this web was showing the boat first steps thanks to Landy & Felix telling me a new A-Cat was being launched. Arno is an experienced A-cat sailor and with PJ they broke new grounds in the A-Class delivering boats in series production, in the process the Dna has won last 3 WC-

After leaving DNA last year Arno wanted to go a step further on what he and the Dna team along Mischa achieved on the foiling ground with the first J foils. That work  launched the class to a full foiling path with a first milestone being Ashby , Burling  and Tuke refining their concept to win the 2014 Worlds in foilign mode downwind, where Nathan Outteridge also showed excellent flying performance (specially in in the low range winds winning with ease some races)  using Jakub's Exploder J version, and the T rudders that were used by Dna and others later on their flight development.

With foiling boats now a reality , after many said As will never fly on  Martin Fischer first racing attempt with Jakub's boat in 2011(they were the racing / flying pioneers in the A-Class) boat builders and top sailors alike are seeking to improve current versions and now the target has clearly become a full foiling A in upwind / downwind modes while seeking the earlier flight possible , just like the Moth.

With this Background, experience and goal in mind Arno has come out with his brain child , the  'Flying Carpet' concept.

The only problem is that beyond he is good sailor with many years on the A, and having achieved top technical skills & knowhow on the Dna project, Arno can't  draw a circle on paper!  

So I offered help to put his ideas on to, a working functional 3D CAD-

I grabbed my already drawn A, and started refining to Arno's concept & ideas. Then with Arno's clear knowledge of foil design and functionality I draw from scratch several new foil versions based on Arno's precise data.

The concept was to have a refined A-Class hull , smaller than current DNA & Exploder , minimizing aero drag, assy hull bottom to maximize foil span, angled front beams, precise beams forward positions , special tramp,  Z boom a la latest Moth, shorter mast height, straight traveller, sail area and overal dimensions (that is a 3D sail also in the cad/render done by the simple but effective Sailcut, a great tool to dimension and draft your sails) , and many details Arno will describe next.

I put some long hours into drawing CAD lines plus details, and then some on rendering, the first draft results can be seeing above. (AC48 hull renders was scaled from this A)

Below Arno presents his his 'Flying Carpet' concept in detail.
'Flying Carpet' by Arno Terra :
"Terra’s Flying Carpet presents the first upwind foiling A-class cat
Foiling downwind on the J and Z boards is great but the time for a full foiling A-class cat has come. I want to bring this new technology to the A-class community and it seems the right time to do it.
It is not a minor upgrade it is a totally different concept and makes foiling easier, faster and more accessible. It is the first A-class designed purely for upwind foiling. It is the boat I want to sail myself and see my friends on.

Once you realize that upwind foiling is possible and that is both the natural and inevitable way to go you enter a new design box. Bigger foils are no longer slow upwind but faster as you will foil most of the time, hulls can be smaller as you no longer need long high volume noses, you can get rid of the curved traveler etc.

What will be delivered is simplicity, good handling, a better aeropackage and better systems. This makes allround foiling happen in 5-25 kts, both upwind and downwind. Not only for the pro’s but for anyone in the A-class community.

The new boat will not get up the foils in 5-6kts either as with any foiler you need 7-8 kts to get up but

once you go up you can stay up. Foiling gybes will be seen for the first time, which will make it possible to stay up the foils even in a dying breeze.

If you foil in 5-6 you are full trapezing. As foiling goes better with a loose sheet and low center of effort it makes sense to shorten the mast, use a longer foot and use the trampoline more as an endplate. This not only improves performance but also solves two class isuses: breaking masts and difficulties with raising capsized boats. The shorter mast is much stronger and is less likely to break under the impact of a capsize and it will be easier to right a capsized boat with the shorter mast and the airtight trampoline.

The daggerboards are a new type Z boards where the tip itself is used for both lift and sideforce, therefore no decoupling of lift and sideforce anymore. It makes the board in foiling position less draggy and more efficient.

The boat comes with a special daggerboard cases of which the deckslider and bottom bearing can be easily be replaced. That way you can fit your favorite daggerboard any moment and be ready for any future daggerboard development. You can even fit C boards and straight boards (not that it is needed, not even in super light winds).

The boat is future proof because you even can increase effective span of the boards by canting the boards more, with more I mean more than the 1,5m rule allows. More span is more lift is earlier lift-off and more foiling fun. Not all your sailing will be race time and eventually the class will abolish rule 8 at least partially. Be assured that with the new boards you will not need to break the rules to be flying in 5-6 kts! It just means that you can make it happen with older types of boards too but just outside official races yet.

The rake of the boards can be adjusted during sailing by a wormdrive system with which you can adjust both boards

individually. The rake of the elevators can be adjusted during sailing too. This assist in early foiling and helps to stay in control in the stronger breeze.
The beams have been moved forward for better flight control. Distance between elevators and daggerboard has been increased significantly which will make the boat longitudinal more stable, which helps to continue accelerating.

You do not need the curved traveler as you will be foiling most of the time. In the rare coccurence that foiling isn’t possible at all you can control the boom with a barberhauler.

The smaller hulls have less aerodrag and will be lighter too.
It will no longer be a cat which can foil, it is a foiler which fits in the A-class rules.
The renders you see are a work in progress. Some small changes can still be applied. Building of the moulds is planned to start end of June, first boat will be ready end of August. Mid October the first containers can be shipped to Australia and both America’s. Our non-European friends are lucky due to the fall of the Euro against all most any other currency.

Price TBD but expect something between current Exploder and DNA prices for the platform.
Feedback on the design is welcome, just as inquiries for purchase.

A special word to Martin Vanzulli who assisted me so patiently in this developing process, translating my ideas to actual Cad lines and for making the great renders of my new love baby. Thanks Martin!

The name of the boat is not yet decided: sofar A30 is the preliminary type name. Thirty not as in 30 foot but in 30 kts."

Arno Terra, April 23, 2015 - 

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