Forums > Stand Up Paddle Foiling

Tubercle effect

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Created by FRP 7 months ago, 13 Nov 2018
FRP
259 posts
13 Nov 2018 9:55AM
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Hi

I was talking this morning to a buddy of mine who races sailboats as a hired crew member. We were talking about how quickly foil technology was advancing and he brought up the "tubercle effect" that is being used on some racing sailboats. Deacresed drag, reduced stalling, improved low speed foil performance. Was wondering if this might improve surf foil performance?

Cheers

Bob

en.m.wikipedia.org/wiki/Tubercle_effect

Piros
QLD, 5442 posts
13 Nov 2018 2:01PM
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At first glance I've gone here we go..... but that is seriously interesting and a good read. I might have a crack at modifying one of my old proto wings and give it a test , other than that can't comment but I like the idea of it.

Nice share Bob

colas
3195 posts
13 Nov 2018 2:22PM
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Select to expand quote
FRP said..
the "tubercle effect" that is being used on some racing sailboats. Deacresed drag, reduced stalling, improved low speed foil performance.


I guess it would more be useful for low speed foiling, such as downwinding or pumping on long distances. You only see them on slower-moving animals (whales, not dolphins).

For foil surfing, I think the Quobba fins team could help a lot in designing more efficient wings...

surfcowboy
26 posts
13 Nov 2018 2:53PM
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Check out the Zone. A guy named container over there has built one of these. He sanded it off I think.

FRP
259 posts
13 Nov 2018 5:52PM
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Yes interesting. When talking to my sailing buddy, where the the tubercle effect was being used was on these large high performance foiling sail boats rudders to reduce drag and get them up on foil at slower speeds. Races like the America's Cup are pushing foil technology looking for every small advantage. Perhaps the effect could be used on the masts of our foil boards?

Bob

FRP
259 posts
14 Nov 2018 9:42AM
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Hopefully my last post on the "tubercle effect'. Another long conversation with my pro sailing friend. Yes it being used on some high performance rudders on large foiling sailboats. "There is no free lunch"
was his final comment. There is a small increase in drag that is traded off for a decreased tendency to "stall" at high angles of attack. I seriously have no good understanding what he is talking about and will leave it at that. I am sure that there is someone on this forum that does have a good grasp of these concepts.

Cheers

Bob

RAL INN
VIC, 2722 posts
14 Nov 2018 12:01PM
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You get high Aoa in foiling when you weight back to lift.
there are times when the foil will lift you but then stall and drop.
The dreaded porpoising.
the solution is hold down a bit till speed builds then have smooth lift.

question then is would it have any benefit. Would it improve your session?



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