vela99 wrote: ↑
Sat Nov 03, 2018 4:23 pm
Geometrically no doubt but in practice?
(From windsurfing I know that changing boom height or mastfoot position only by 5mm can make a big difference in performance).
I only want to avoid going for the shortening to learn afterwards that I changed the kite character in a point I did not want to change.
This one is going to be hard for me to articulate simply, so I will do it on 2 levels. Essentially, kiting and windsurfing have completely different controls and feedback. Throw out what you know about windsurfing control inputs and feedback and completely start over with kite controls and feedback. The seemingly similar nature of kiting and windsurfing will make you think you can use some of the same physical/mental skills, but you cannot. You need to start over.
Kiting is not windsurfing.
, you can push, pull, twist, rake the mast back/forward, put variable downward pressure on the mast foot/universal. This makes subtle movements or changes in posture, and tiny adjustments of an extremely precise nature, which all have compounded and/or large effects. In windsurfing you are part of a tuned machine with rigid gears and precise springs with "setting determined" spring constants.
......you can only pull on a rope - rope as in your kite lines. There is NO mast foot pressure, NO raking the sail back (without the kite changing positions in the sky), and NO twisting against the board (your front foot, back foot, and connection of the mast to the board - though there are 2 exceptions to that). In kiteboarding you are just a link in a chain.
Kite controls and feedback through those controls bear virtually no resemblance to windsurfing controls and feedback.
, moving an adjustment .5cm has the effect of changing the geometry of EVERYTHING in the system due to the rigidity and potential flexibility under load AND variation of loads possible when rigged on different settings. Moving your mast base .5cm will change the amount of sail rake you apply to get your harness point at the same location while in the foot straps. Or if you move the foot straps .5cm, you will will affect the amount of sail rake. You can even create more "on the fly" adjustability with loose straps or harness lines that are further apart (need more length too compensate for moving apart). This is accomplished by simply using loose or tight foot straps, and close or far apart harness lines. Rigid adjustments, such as mast base location, can also be made flexible or rigid via the use of a rubber universal, a tendon universal, or a mechanical universal. And this mast base placement in the track obviously effects the leverage you have over the board with mast base pressure applied via the harness lines. But that, in turn, also affects the leverage of the mast base/fin sideloading via the feet load line. If you truly examine a single windsurfing rigging adjustment, you will find out that it is not one change, but rather 6-10 changes that you need to compensate for.
Think about moving your boom up. If you do that, you will also need to lengthen your harness lines. If you don't lengthen your harness lines, the higher harness connection will force your body to be more upright than ideal. This in turn stretches out your legs, or you would need to rake the sail back more to stop from having to stretch out your posture so much. If you rake back the sail more, then the angle that the mast base pressures the board is different, even thought it connects at the same place same place. Then the center of effort of the sail will also be further back.
But if you do lengthen your harness lines, then you have just created a longer triangle that applies force to the boom. This means that some mast pressure can be lost since you can no longer "push" the boom forward as much with the harness lines. Moving your harness lines closer can also have this effect when boom height is kept the same. I can go on and on about the multitude of adjustments a windsurfer has, but I could never cover them all. In the end, the reality is that one .5cm adjustment induces a 2cm adjustment in your body, a -4cm adjustment in leverage over the fin, and a 1.5cm adjustment in the effective location of mast base pressure (I know I am missing some too). So you did not just move your mast foot position by .5cm. You did that AND
changed 6-10 other measurements, some smaller than .5cm, and some bigger than .5cm.
, there is no pushing and pulling since the distance and connection to the sail via long lines, means you have only pull directly in line with those lines (a twisting moment is possible, but almost no one but kite racers use that). The only difference in kite settings (within parameters where the kite still functions) are:
1. Pull of the kite and depower capability (pull in line with the kite lines)
2. Forward flying speed through the window via bridal settings (how fast the kite changes the direction of pull, still always in-line with the kite lines)
3. Turning speed (essentially the same as #2 in that the turning kite is still pulling in line with the kite lines, but the rate of change in the direction of pull defines the effect).
This is the explanation of why kiteboarding is soooooooo much simpler and easier (though inherently more dangerous in most ways) than windsurfing. If you continue to apply windsurfing technical knowledge to kitesurfing, you will get it very wrong. Windsurfing is calculus, kitesurfing is basic math. You do not use calculus to find the answer to 2+2.