cor wrote: ↑
Wed Sep 12, 2018 10:20 am
IainMacaskill wrote: ↑
Tue Sep 11, 2018 10:28 pm
Please can someone who knows tell me the real reason some foils Howl?
Because they are happy!
Ha haa, yes they are happy
There can be many reasons, obviously it is oscillations in the water at a frequency we can hear.
It is very often from the trailing edge, can be of ANY part of the foil, being too round or having an odd shape even if not round, or wing having the wrong shape at the last centimeters before the trailing edge.
But it can also be scratches on the wings or fuselage or mast, or the interconnections, or the screws.
Salt, I have never heard about that?
Usually the foils that "Howls" gets more and more aggressive (higher/louder) the faster you go.
But one thing CAN happen if you ride too slow but still foil: Low AR stable wings tends to vibrate or even hum very low frequency (deeper tones usually not possible to hear, just opposite to the high pitch howling at high speeds), because these wings get huge tip vortices (oscillations/vibrations) when semi stalled, which is actually good as it is a stall warning you can feel, BEFORE they stall, so you can still ride in this state for a while, and push forward or more kitepull so you avoid the stall - excellent
Whereas superhigh AR narrow wings dont give you any warning, they simply drop you like a rock if you ride too slow, NO warning at all.
Regarding the classic howling though, it can be REALLY a PITA to find where it origins from - you might be lucky to find it quickly (and if others got the same on the very same foil and solved it you could use this as first approach), but as it can be the TE of the mast, the wing, the stabilizer(s), the fuselage - or the interconnections, or the surface, or the design/curves, or the holes/screws it can be pretty frustrating to find