Toby wrote: ↑
Thu Mar 18, 2021 5:31 am
Does the foil have more drag with a heavy rider?
I assume the smaller kite of a less heavier rider also has less drag...
Maybe we can relate it to sailing...will a heavier rider be faster, since he can hold more power in the sail, but also might have more drag on the hull ?
Yes, a heavier rider has always more drag. So in lightwind with the same sized kite the lighter might win. However if both rider riding the same foil and board setup with right sized kites, than the heavier rider will be faster(if their riding skill is equal). Lets say the lighter rider is riding a 15meter race kite and the heavier rider riding the 18 meter race kite.
Larger wings has better performances than smaller wings. The 15 M kite will have a glide ratio of ca. 10.6 and the 18M kite will have 10.8 (I am just guessing the glide ratios, but competition paragliders with aspect ratios of 7.5 easily have best the glide ratio around 12 or even more but they are also roughly 25 meter is size.)
The reason is physics, where a larger wing of the same size will have better performance (glide ratio). Than another factor is added up to this that a smaller kite is never a perfect minimalization of a larger kite. While they might reduce the size of the kite and the lenght of the lines they not reduce the thickness of the lines, or the weight and thickness of the materials etc, so some part of the drag is more or less the same.
Also the lighter rider usually does not have a smaller foil or thinner mast or smaller board and the rider weight compared to the foil and board is also advantages the heavier rider.
Even if the perfect minimalization would happen that the smaller rider would ride a smaller foil, board, and perfectly minimalized kite the larger kites and foils (wings) would still perform better.
The only situation where a lighter rider can win is lightwind/underpowered condition where the heavier rider has to pull more bar=higher AOA what means worse glide ratios.