Jan 19, 2014

A-Cat Flex on C Foils: Alternative Flying solution by Brett Burvill

I contacted Brett Burvill from Windrush Yachts Australia, builders of the Windrush F18, as he is offering and delivering to top A-Class riders their new C daggers. Interesting to see how the flex approach is maximized to generate the extra lift provided by a J or L dagger. In Formula Windsurfing foils flex is key, and I always wondered if someone has ever done some specific tests in racing beachcats. I once discussed this with Andrew McPherson and he told me the stiffer the better for the F18s.
For the As, and as Raphael Censier's custom tests using a home made flexible dagger provide him with airborne time with a legal conf even before Mischa's Dna Js.

Brett Burvill on his new  C foils:
"I have been developing over time a foil for the A cat that is a curved C foil as per the old Standard DNA and others C foils. It has a radius of 1200mm .Windrush have developed a way to manufacture the foils so that they can bend quite a lot and this has the effect of increasing the vertical lift component of the foil for the same surface area.

This is the easiest way to fly yet for A cats, if you have rudder wings already then just slide in the board and fly from about 12+ knots . The difficult thing is to make it bend without failure and to date we have had great success. You will have seen the picture with 190 kg standing atop the A board!!

We have 4 different specifications of laminate from X stiff, stiff through flex to soft .
Jack Benson has sailed with all 4 and his feeling is that the soft gave him the best advantage. Upwind he was not suffering any loss of height and as the wind got up and speeds became high he had more lift upwind too.

Full description and insights by Burvill at http://www.a-cat.org/?q=node/326