Passionating topic. I had actually launched a polemical topic on french forums 2 weeks ago about the pure upwind angle of a medium ratio foilkite vs race foilkites, to challenge the simple idea that a race kite has necessarily a higher upwind angle ... nice reactions of a lot of riders
who mixed VMG and upwind angle ...
So ! Sorry I only read this topic right now and'll have some delayed remarks:
- Sergio mentioned that the speed ratio wind vs rider speed is crucial ; right !!! and we should focus on that point IMO ;
- so, IMO rather than trying to get a higher L/D ratio of the kite or of the HF, focussing on a slow planning HF and a kite that develops lift at low speed is the key to reach the higher angle . Again I do not talk about VMG which is competitors focus, just pure angle whatever the (low) speed.
- a very large HF (and/or a very light rider
) could "win" even if not the best race kite (for a given kite size)
I do not see barriers to do far better angles than above angle figures, but with far bigger/slower HF; Imagine you have a support like a big-beginner sailboard that can hold your weight at 0 speed ; you can put your kite at (almost) 90 degree, with you up on the floating board ; then you add a big deep fin in the center of the board ; if you point the board at 20 degree wrt the wind direction, the fin will remove lateral drift, and you should still go slowly upwind (very close to) 20 degree, no ?
To me the actually physical barrier is only the "cumulated" L/D ratios angles of the kite + the board ; assuming L/D=10 for the kite and same for the board, you can then go upwind up to 12 degrees ...
So we need to look for an enormous Hydrofoil
and a grunty kite that delivers power at very low speed (medium ratio) ; a bit provocative, I know ...