Has anyone ever tried any wing articulation tricks to enable small wings to achieve good lift at low speeds. I'm thinking of things like flaps and those leading edge pop-out things that Willy Messerschmidt was so fond of? Too much trouble? Don't work? Silly waste of effort?

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GasHazard said..
Has anyone ever tried any wing articulation tricks to enable small wings to achieve good lift at low speeds. I'm thinking of things like flaps and those leading edge pop-out things that Willy Messerschmidt was so fond of? Too much trouble? Don't work? Silly waste of effort?

AC boats have complex flaps and they work well. Their budgets are also a lot higher. I have a friend who sails a foiling A Cats and they have very neat but complex systems to trim the rudder/stab which also work very well.

For us, complexity is a key issue. Our wings/fuses are small and expensive as it is. The ideas you suggest need some way to sense speed automatically or have remote control. That's either a lot of technology to cram into a very small space (even if just mechanical like springs, etc) or you need to have mechanical or electrical connections running up the mast into the board. Now you have to deal with more complex fuses, masts, etc. And just for fun, this all has to work in a corrosive salt-water environment.

Just giving it a quick think, I'd say that some sort of auto trim of the stab is the more likely method where stab angle would vary by the amount of pressure on it. But you'd need a method of tuning that at least for variations in rider weight and skill. (Maybe something like different elastomer density?)

www.taaroa-hydrofoil.com/iup-product
I have been waiting patiently, there is no question in my mind this has potential.

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utcminusfour said..
www.taaroa-hydrofoil.com/iup-product
I have been waiting patiently, there is no question in my mind this has potential.

Maybe it's just me or "generational" but it seems like we live in an era where people expect an "app" to be developed for every existing and non-existing problem. Don't get me wrong, I'm not against technological evolution and e.g. really like my Shimano Di2 equipped bike but would you really want/ need yet another battery to be charged and/or system to be updated before goiing on the water.?

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Bellerophon said..

utcminusfour said..
www.taaroa-hydrofoil.com/iup-product
I have been waiting patiently, there is no question in my mind this has potential.

Maybe it's just me or "generational" but it seems like we live in an era where people expect an "app" to be developed for every existing and non-existing problem. Don't get me wrong, I'm not against technological evolution and e.g. really like my Shimano Di2 equipped bike but would you really want/ need yet another battery to be charged and/or system to be updated before goiing on the water.?

Here's why I think you are wro

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utcminusfour said..
www.taaroa-hydrofoil.com/iup-product
I have been waiting patiently, there is no question in my mind this has potential.

I totally agree that there's potential and absolute case in point about complexity. Over two years since first demos and four years since they first explored the idea. Still in "pre-order" stage. Given that people pay $10-12k for an efoil, I think someone will pay up for it when it does, eventually, make it to market.

Their blog in March 2020: www.taaroa-hydrofoil.com/blog/what-s-new-1/iup-flying-made-easy-and-safe-with-an-a-i-powered-hydrofoil-5

"In fact, TAAROA has spent the last two years perfecting the heart of this next-generation foil. "

for me those mechanisms defeat the entire point of windsurfing, which is the direct connection of board, sail and sailor - if you are pulling ropes and activating mechanisms then it's a mishmash with dinghy sailing but for some reason you still are up there pulling the sail from the boom

they do make a lot of sense in racing cats and the like though

Since I sail in a really gusty place with long lull-gusts ratios, I would not mind a three position stab. It could even be mechanical so old farts don't complain about technology :)

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WillyWind said..
Since I sail in a really gusty place with long lull-gusts ratios, I would not mind a three position stab. It could even be mechanical so old farts don't complain about technology :)

The Taaroa stab is multi-position. It sits in a curved bed and moves from negative to positive lift depending on where you tighten it down. Not in-flight adjustable but easy on the water if you carry a Torx wrench along. Makes a huge difference, especially if you find yourself with too much lift if the wind picks up unexpectedly.

I posted for the fun of seeing all the knickers get twisted up! Y'all are consistent!
It was not long ago many were bashing the dangerous and complicated new sport of windfoil.
When I chat with my buds who race moths, wasps and A cats I realize that I have foiling skills that they may not. That is unless they ride foil boards. Good foil boarders make millions of tiny subconscious ride height corrections a session because it's all up to the rider.
I have a bud who has done well in the wasp and moth, I asked him if he moves his weight much for ride height. He said NO, that's what the wand is for. This dude is a 3 time Sunfish world champion! He is learning to foilboard now and I bet he will start moving his weight around on the foiling boats more. When you know what the challenges are for the machine you can help it help you.
When, not if this tech gets available/affordable I will give it go! That is if I still can;)
I bet Houre was the first to use the stab in an arced saddle, shims are silly after you have used that design.

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Awalkspoiled said..
The Taaroa stab is multi-position. It sits in a curved bed and moves from negative to positive lift depending on where you tighten it down. Not in-flight adjustable but easy on the water if you carry a Torx wrench along. Makes a huge difference, especially if you find yourself with too much lift if the wind picks up unexpectedly.

Yeah, I was pretty close to test a prototype a couple of years ago but in the end the company took forever to have a finished product. That happened at the same time winging was taking off so my guess is they moved all their R&D more towards wingydinghy.

I think there's a thread on here somewhere it was brough up before.

I do wonder if battery tech will get better for this, because a friend let me try out an efoil for a bit when the wind dropped. He set it in the water for me, and I noticed some tail weight, but I was blown away by how heavy the board and battery are.

The batteries for those are like $4k USD

For a smaller control device it'll add some weight dor battery and the sealing box around it, and I'm wondering how the connection will be made to articulate the foils and get sensors. The efoils also have a cooling loop, which is heavy and may be much smaller or nonexistent for a small computer, sensors, and servos but maybe not? But yeah, I like the challenge of foiling as it is. Seems like it would be cool to have control loops for top speeds but for normal riding in casual foiling around 15-20+ kts I don't normally crash anymore, just turns . I'd send it harder with some more stability there.

Speculating that Team NZ AC test boat not using flaps but depending on rudder (stab) trim only. Interesting discussing for tech oriented. The guy making the point is a windfoiler and contrasts how a windfoiler/winger trims vs Moth.

20:02

My thoughts.

we only need :
a few degrees adjustment on the tail wing.
IN-frequent adjustment. I'd actually be happy to make a
setting adjustment after a run not necessarily during it. For example in slalom races or during a speed run it is very rare to adjust the outhaul. Usually you set it and go!
maybe a deck mounted Adjustment that comes through the third / middle hole of the Tuttle box. Use a flexible bike brake cable that passes through the mast and fuselage
magic engineering mechanism to move tail wing angle or flaps on trailing edge. But remember the tail wing needs to be solid!

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berowne said..

maybe a deck mounted Adjustment that comes through the third / middle hole of the Tuttle box. Use a flexible bike brake cable that passes through the mast and fuselage

Now that's a good idea. Maybe something like a bike twist shifter on the boom with 1/4 degree increments?

Exactly... so the top end is solved basically...
But actuating the ailerons I'm not so sure about. Most wings have hollow space for mechanisms and we need both sides of the wing to raise/lower precisely together!

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berowne said..
Exactly... so the top end is solved basically...
But actuating the ailerons I'm not so sure about. Most wings have hollow space for mechanisms and we need both sides of the wing to raise/lower precisely together!

Single hinge on the stab. Like an active shim

Two ideas for control surface

MOVING WING
a curved tail wing saddle with a sliding trolley to hold the carbon wing limiting motion to one axis.

FLAPS
A fixed wing with moving rear flap aileron.

MECHANISM
in either case the cable should attach to an internal cam and spring in the rear of the fuselage ahead of the tail wing u fortunately adding as litttle bulk as possible.

The actual movement can then be via a push/pull rod internal for the moving wing or above the fuselage and tail wing for moving the aileron

model aircraft might have some clues or even helicopter rotor manipulators?

Alternative mechanism is a stearing rack and pinon, the pinon rotating the rear flap... like the hand brake but at a different angle
So have a strong spring at A to return the cable which is attached to the top.
Pulling the cable lowers the flap via tension.
Release the cable raises the flap via spring.