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Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Feb 13, 2019 6:42 pm
by plummet
Very interesting chat. Yes i agree Peter, we need more data. There appears to be a vast variation in a successful platform. Keep your measurements coming.
Re: Surf/wave wing thickness and NACA profiles
Posted: Tue Dec 17, 2019 6:12 pm
by plummet
Hey team. I'm back into thinking about the ideal wings. Any one got more data they can share?
Perhaps theres some newer designs out there that guys have ridden?
Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Dec 18, 2019 12:15 pm
by airsail
Just finished and ridden my latest wing. Initial was 1.2” thick, (30 mm) about 1100 sqcm. This one is .66” thick but 1200 sqcm.
The thick wing has a roughness about it, I think caused by buffeting of the rear stab by the thick wing. The new wing is smooth and silent, gained about 4 knots in top speed, about 22 knots and crazy low speed.
In my experience a thin, large area wing is preferable to a thick slow wing. It provides enough speed to link swell sections and not boring to ride when covering distances.
Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Dec 18, 2019 4:06 pm
by jumptheshark
Plummet,
Your a confessed speedster. Everything I've read points to the logic that thin profiles preserve more top end speed where thicker profiles provide more lift at lower speeds. For kiting, especially your style and conditions, I would think it makes sense to stick to a relatively thin profile. Thick profiles might be great for the people pioneering the Peak 4 style of kitefoiling, where the goal is to have as much time on the wave with no drive from the kite. Similar to wing foiling.
Thin profile seems like a much better fit for people in big waves with high swell speed, and those on the other end in piddly little wind driven swell that in open water are short lived and cannot provide much in the line of long unsupported rides.
I've made peace with the fact that I'll always want the kite to be actively involved in my foiling. I have to be able to shut it off, but not for very long. I would imagine you are in the same boat for very different reasons. Boat speed is important to both of us. This style of riding is likely a lot less suited to the thicker types of SUP and Surf specific wings.
I see a clip like this and wonder if those on Peak 4 identify in the same way. I also wonder if its even possible to rip around at that pace with a thicker profile wing.
viewtopic.php?f=196&t=2398613&start=40
Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Dec 18, 2019 4:17 pm
by PurdyKiter
Thick vs Thin.....
Can someone comment what a thin profile wing will do vs thick when it comes to "breaching" air? I've switched to a thinner profile after a year on a Moses 633. Now the instant I hear the gurggling sound of air-on-wing I'm crashing on my face again. With the Moses I had a millisecond to correct.
Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Dec 18, 2019 4:29 pm
by geokite
I can ride my Lift surf wing (170fish) with the front wing constantly breaching, putting along. Kite is high, I'm going slow when I can do this. Can't do this with my thinner 170 Classic.
Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Dec 18, 2019 5:20 pm
by tkaraszewski
This article has the most info I've seen in a published format about the hydrodynamics of a racing foil:
http://www.tspeer.com/Aclass/A-ClassCatamaranFoils.pdf
It's focused on A-class catamarans but the concepts are the same.
One thing about "high" vs "low" lift wings for a kite hydrofoil is that this is a misnomer. All wings produce roughly the same lift. If they produce more than that, they lift you out of the water. If they produce less than that, then you can't stay on foil. The question isn't about the amount of lift a foil can produce, but about the other parameters that need to be true when the correct amount of lift is generated (speed, AOA, amount of drag). Race foils are generally intended to produce the most speed with the least drag. Surf foils are intended to produce the required lift at low speeds, with less concern about drag at higher speeds.
Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Dec 18, 2019 5:44 pm
by kitexpert
tkaraszewski wrote: ↑Wed Dec 18, 2019 5:20 pm
This article has the most info I've seen in a published format about the hydrodynamics of a racing foil:
http://www.tspeer.com/Aclass/A-ClassCatamaranFoils.pdf
It's focused on A-class catamarans but the concepts are the same.
One thing about "high" vs "low" lift wings for a kite hydrofoil is that this is a misnomer. All wings produce roughly the same lift. If they produce more than that, they lift you out of the water. If they produce less than that, then you can't stay on foil. The question isn't about the amount of lift a foil can produce, but about the other parameters that need to be true when the correct amount of lift is generated (speed, AOA, amount of drag). Race foils are generally intended to produce the most speed with the least drag. Surf foils are intended to produce the required lift at low speeds, with less concern about drag at higher speeds.
All wings roughly same lift? No, bigger and thicker wings give you more lift, just like bigger (and thicker) kite does. Variable is the board speed, big wing can lift you up in slow speed, small wing needs more speed of course.
Race foils are small and efficient (low drag) because they are to be used in high speeds. Kite produces the speed, not the foil.
Surf foils are so big you can't keep them under water if speed gets too high. Personally I like quite thick and big wings because using them is so laid back. I don't even want to get speed high.
Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Dec 18, 2019 6:09 pm
by plummet
airsail wrote: ↑Wed Dec 18, 2019 12:15 pm
Just finished and ridden my latest wing. Initial was 1.2” thick, (30 mm) about 1100 sqcm. This one is .66” thick but 1200 sqcm.
The thick wing has a roughness about it, I think caused by buffeting of the rear stab by the thick wing. The new wing is smooth and silent, gained about 4 knots in top speed, about 22 knots and crazy low speed.
In my experience a thin, large area wing is preferable to a thick slow wing. It provides enough speed to link swell sections and not boring to ride when covering distances.
Can you share a picture or 2 of your creation?
Re: Surf/wave wing thickness and NACA profiles
Posted: Wed Dec 18, 2019 6:20 pm
by plummet
jumptheshark wrote: ↑Wed Dec 18, 2019 4:06 pm
Plummet,
Your a confessed speedster. Everything I've read points to the logic that thin profiles preserve more top end speed where thicker profiles provide more lift at lower speeds. For kiting, especially your style and conditions, I would think it makes sense to stick to a relatively thin profile. Thick profiles might be great for the people pioneering the Peak 4 style of kitefoiling, where the goal is to have as much time on the wave with no drive from the kite. Similar to wing foiling.
Thin profile seems like a much better fit for people in big waves with high swell speed, and those on the other end in piddly little wind driven swell that in open water are short lived and cannot provide much in the line of long unsupported rides.
I've made peace with the fact that I'll always want the kite to be actively involved in my foiling. I have to be able to shut it off, but not for very long. I would imagine you are in the same boat for very different reasons. Boat speed is important to both of us. This style of riding is likely a lot less suited to the thicker types of SUP and Surf specific wings.
I see a clip like this and wonder if those on Peak 4 identify in the same way. I also wonder if its even possible to rip around at that pace with a thicker profile wing.
viewtopic.php?f=196&t=2398613&start=40
You are right, I am not a slow tighter turning wave rider that wants to try to be a surfer. I want speed and flow and carve on the wave and to actively fly the kite. The kite flying in the vid is very close to how I like to fly.
I am hearing you re thin profiles. My current thinking is a similar profile thickness to what I have now and gaining some stability through anhedral/dihedral rather than thickness and surface area.