But its harder to sink more displacement/volume which means more float, which equals earlier planning or riding through lulls...Matteo V wrote: ↑Sun Feb 18, 2018 3:35 pmAgain, this is the misconception that almost all windsurfers carry over to kiteboarding. But even in windsurfing, volume over anything that floats with just a bit of freeboard is luggage at sub planing speeds - even on a shortboard. This excess volume IS helpful when displacement windsurfing as it adds stability when a rail is pressured at these non-planing displacement speeds. But once the force of the water pushing up on the (sub)planing surface, even at sub planing speeds, becomes the dominant force holding the board up - volume is no longer a part of the equation.
The best way to conceptualize this is if you have a completely cut away deck down to the bottom layer of the board (no volume) and you start moving. Once you are moving, the water on top will fall off the back of the board and only planing forces will be holding the board up. Obviously this will not work in windsurfing, but it does work in kitesurfing. And it happens all of the time with TT's. Look down at you TT next time you are slowing down to a crawl. There is no volume there, so only the planing forces are working to keep the board up.
Volume is displacement and for displacement to have an effect, the volume must be submerged.
Again, float is only due to displacement at zero speed, AND ONLY when the board is sunk. If you have any movement, you are not using any of the displacement, but rather planing forces.
kitejumping wrote: ↑Mon Feb 19, 2018 3:54 pmI wouldn't consider 10 knots lightwind at all, if you have a really big kite. A 20m PL Aero or 21m sonic race will have you doing big floaty jumps on a 130tt in much less wind if you know how to fly it. The upper end on my 20m aero ultralight is like 14 knots lol.
Sinking the volume of the board - going from planing forces to displacement force - is a huge waste of energy - at least to get back to planing from that displacement mode. A submerged board has much more surface/sub-surface drag, than when you are just at the sub-planing stage. I have a hard time believing I have never seen this if it is a real thing. Is there a video of someone with good hydrofoiling skills STOPPING and standing there in light winds while the submerged displacement keeps them up out of the water for a 4 second count/ kite parked? And again, how would this be necessary or desired to give up that energy?Peter_Frank wrote: ↑Mon Feb 19, 2018 12:07 pm.....standing fully "parked with zero speed" occasionally, with a given kite, trust me
I stick to the statement, that it is all about keeping the "transition energy needed" from non foiling to foiling as low and short as possible, thus flotation is good when trying to get moving from a standstill
And none taken. I appreciate when someone can stick to their argument without resorting to logical fallacies such as "Straw man" or "Ad Hominem". As I do not see any of those presented to me yet, I definitely could be missing a piece of information on the mechanics of the hydrofoil board volume issue. I have been wrong before, and I could be wrong either now or in the future.
Now think about doing it while holding on to a magical rope from the sky, or ... a kite. The kite gives you all the stability you need. Perhaps you think the kite is parked in these situations, it is not. You'll typically be flying it back and forth to generate lift and provide stability.
Users browsing this forum: Bing [Bot] and 13 guests