Jul 3, 2014

A-Cat Euros @Bordeaux: Ashby sailing skills, Mischa & Dna devel boards.



Mischa's Video from Garda by Jesús Renedo. Image left Gordon Upton.  PJ & Arno made the Dna fly with the feedback of Mischa Heemskerk as the factory rider. The three of them with Landy's Winglets are the origin of current A-Class legal setups in parallel with Jakub Kopylowicz's work that started with Nathan's boat at Takapuna.
Ashby won at Bordeaux with a Dna equipped with Mischa's new stepped foils designed along Arno Terra & Gonzalo Redondo.

Mischa Heemskerk reports below on the development of these new boards:
"After the first event in Muiderzand I had a lot of ventilation on the board and I saw the other guys had problems to keep their boat flying.

I kept sanding the leading edge of the board to maintain a longer flow over the profile which had a positive effect.After the event I was convinced we needed a different profile shape to be both more effective (less drag) and more for giving. An asymmetric profile provides both those answers. With the A cat we want both foils

in the water so we did not need an aggressive asymmetric foil shape but a moderate shape with low drag. We asked Gonzalo Rodondo to provide us with a modified Naca profile to meet the requirements.

Additional comments by Arno at : dnacat.blogspot.nl/2014/07/flying-dna.html
I focused on the geometry of the foil to balance all the forces. During my holiday in the USA with my wife I took several hours in the morning to work on the idea's (they where semi happy with me cause my mind was on this foil).

I made the whole forces structure of the boat in flight with all the calculation to righting moment, side force, weight, uploading of the both boards. The idea is that both boards upload each other to get to an easy and early lift off. Estimated the speed and determined right hide in relation to what I thought was a good height, around 45cm of flight height.


Made the little tip at the end the maximum length which would still fit in the daggerboard case for future upwind foiling side force.

In Garda there where already moments where I managed upwind foiling but it needs more practice.

To bad I can not be with the guys at the A cat Europeans. But I am very happy to hear their reactions to the foils. Chris Field my training partner called me after the first time sailing with them and he was trough the roof of excitement.

His words where "you nailed it mate, they are incredible". That makes all the long hours spent on this project worth it. My dad and I drove to Germany to pick up the moulds at 5 in the morning to be able to have a set to Garda in time. PJ worked all weekend to laminate the boards and flew with them to Garda. 


Nice to see that this group of enthusiastic friends are making things happening.

Thanks to Jakub from Exploder to provide us with his rudder blades which coop very well with the boards.
Greetings,
Mischa"

Follow Mischa's developments and sailing at his FB page https://www.facebook.com/mischa.heemskerk.3

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