obenebo said..
I'm trying to understand what the problem here is. Foils can now do close to 40kn, so controlling that is up to the rider.
Downwinding on swells, where it is difficult to control consistent mastfoot pressure, I'm constantly turning "frontside to heelside", riding the wave, if I do go straight, yeah, lift, yaw, and roll instability come into play - so I avoid that by keeping turning - simple. The smaller the wings, the faster and tighter the turns.
Remember that stabiliser "lift" on a foil also equates to "rocker", when carving the foil with canted mast. A foil setup that seems to lift excessively on the flat, might actually carve turns beautifully. Carve harder Azy?
Btw, I'm still on 2017 MFC foils, ~550cm2 / ~670cm2 / ~970cm2 - have you tried them?
With my AFS W95 and S670 cm2 wing I can go almost straight downwind and really moving, first time I did a long downwind run decided to stop and take a break cause I was going so fast and needed to recalibrate my senses!, I have missed that kind of speed since switching from windsurfing to windfoiling. And never noticed an issue with "lift, yaw, and roll instability" when going downwind. The only issue is coming down a larger swell need to make sure I keep the board nose up, so do not drop too steeply, otherwise the nose on my longer Bolt 135 can catch the water in front of the swell and then it is all over.
And that was before I got the wing and stab. aligned properly with the mast. Can only go faster with everything aligned and without the front stab. shim.
V1 stab., I believe, on left, S670 cm2 wing on right, proportions just look right to me.