Author Topic: Foil stall meter - idea  (Read 2762 times)

red_tx

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Foil stall meter - idea
« on: April 13, 2019, 12:34:30 PM »
Anyone ever considered a meter on top of the board that was some hybrid between a level and a depth gauge for the foil?

We have all seen and experienced when the foil breaches the water on leading edge of wing. (FACE SLAM). I was just watching pono's post in the wind powered section and was reminded of this idea.

Maybe something like this would be mounted on the front of the board and help folks keep the foil down below the water. After a while you would not look at it.

I believe it would help learning foiling, and then adjusting to new mast lengths etc.

In theory it would have the ability to determine:
Pitch
Roll
Foil Depth

I am not sure yaw applies here but it hurts my brain to go there.

What do you think?
-red

PonoBill

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Re: Foil stall meter - idea
« Reply #1 on: April 13, 2019, 12:47:40 PM »
The way things go bad on a foil, I don't think a meter would help much. I always know when I'm going to over foil, I just can't do much about it. I can push as hard as I like on the front, it's just too late. By the time you equipped a meter with some kind of surface sensor you could use the same equipment to control the stabilizer to prevent overfoiling. A lot of the sailboats that are foil-equipped use a surface detector to control the AOA of the foil. They generally go a lot faster than we do, and the systems work despite the foil having a huge amount of potential lift at those speeds. Of course the problem with any kind of system like this, is that when everything goes REALLY pear-shaped the crash is much worse. Search YouTube for Moth crashes to see what I mean. Like being strapped to a Polaris missle.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

surfcowboy

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Re: Foil stall meter - idea
« Reply #2 on: April 14, 2019, 04:40:38 AM »
Also I’ve never seen a time when looking down during a board sport is a good thing.

I think Pono’s right.  If you have a sensor, use it for control. Otherwise you have a product that’s only used while learning which is a business disaster.

Beasho

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Re: Foil stall meter - idea
« Reply #3 on: April 14, 2019, 08:41:36 AM »
Foiling is like any other sport.  It takes time to get good, or even to not fall.  But if you have less than 20 sessions it's like a 10 year old kid making comments on a surfboard's design when he had only ridden it 5 times. 

"Ok kid.  Give it a year and get back to me."  I don't mean this to be harsh, actually more motivating for the average person willing to take a few knocks in the surf (proverbial knocks). 

This stuff is not rocket science, even better it is actually EASY.  I am, for some reason, the only person who has ever said this.  My only secret sauce is I give everything 10 tries before I comment on how hard or easy it is. 

Weight forward.  Do not even try to fly.  Surf nose down, slowly on a 3 foot wave.  Start to go down the line and then slowly put pressure on back foot . . .

PS:  The biggest problem is with breach.  Stall occurs on these wings below 6 mph.  You rarely experience stall except when you turn 180 to kick out of a wave and promptly drop.
« Last Edit: April 14, 2019, 09:01:43 AM by Beasho »

red_tx

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Re: Foil stall meter - idea
« Reply #4 on: April 14, 2019, 09:14:59 AM »
Thanks for the feedback folks. For the record, I am in no way even a beginner. I am lesser than that. I have only flown behind the boat and then I caught one tiny wave paddling in from the boat after he dropped me off.

I was not expecting to catch the wave then all of a sudden I was flying. That was surprisingly easy.

I'll just duct tape a level on the front of my board :)

Super stoked on foiling and just thought I would float my idea.
-red

PonoBill

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Re: Foil stall meter - idea
« Reply #5 on: April 14, 2019, 10:57:31 AM »
Ideas are where innovation come from. It's just that not a lot of them work. That's why my best business advice to people is to fail as fast and often as they can, but don't make the same mistake twice. My biggest business disasters come from doing things I already knew were wrong. My biggest successes came from doing things other people told me wouldn't work. Two sides of the same coin. Keep thinking about your idea.

But if you want your ideas to have merit you need to research how foils work and how they have been used throughout their history. The tech is about a hundred years old, there's lots of information about how people controlled them. The biggest challenge with a foil is that lift increases as the square of the velocity. In air that isn't quite as big a problem because all the other coefficients are so small, but water is 1000 times more dense, a widely variable number associated with air density that helps to tame lift resolves to an unchanging 1 in incompressible water. Even still, airplane wings have complexities like flaps to increase lift at lower speed. We're using simple, unsophisticated wings and systems to fly through water with a great variation in speed. It's crazy that it works.
« Last Edit: April 14, 2019, 11:07:33 AM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

supunk

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Re: Foil stall meter - idea
« Reply #6 on: April 14, 2019, 11:28:13 AM »
Put a small whistle on your mast just above the wing :)

red_tx

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Re: Foil stall meter - idea
« Reply #7 on: April 14, 2019, 12:07:48 PM »
Put a small whistle on your mast just above the wing :)

Supunk, Thanks! most clever response yet!

Wonder which whistle would whine when wet?

-wed
« Last Edit: April 14, 2019, 12:12:28 PM by red_tx »

supunk

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Re: Foil stall meter - idea
« Reply #8 on: April 14, 2019, 12:48:19 PM »
I have seriously considered this. May add a little drag!

red_tx

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Re: Foil stall meter - idea
« Reply #9 on: April 14, 2019, 01:23:00 PM »
At first I thought of a deer whistle. Then I remembered they are inaudible to humans. And the drag looks crazy. Then I thought of a Kazoo.

Remember when you were a kid, or just the other day with your kid when you take a blade of grass and stretch it between your thumb and palm and blow, fist balled up, hollow?

Now I am thinking something taped to the mast that flaps then it breaches. Like a small piece of tape with a tiny straw under it to keep it from sealing to the mast if that makes sense. Once you reach a certain altitude (from water surface) it immediately starts flapping.

Obviously you would put it in a position *before* the wing breaches so that you knew you were close(r).

fun to think about and I will try whatever we come up with if we do. 
-red

PonoBill

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Re: Foil stall meter - idea
« Reply #10 on: April 14, 2019, 05:58:49 PM »
If you sand the trailing edge so it comes to a rounded point instead of a squared edge it will whistle as much as you like.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Piros

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Re: Foil stall meter - idea
« Reply #11 on: April 15, 2019, 03:21:55 AM »
My very first Kai Go Foil used to whistle when the wing got near the surface but as Bill said earlier all it did was let me know I was about to face plant , I couldn’t do a thing about it. Having said that as I got better it really did help. I sold it to get the triple pack and none of the new wings did the same thing . I often though about something near the mast base when it came out of the water it would whistle.

Really don’t need it now as I can actually hear the water gurgling or the foil breathing when it’s breaking the surface and I can stay on and ride through it but still think the idea has merit.
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PonoBill

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Re: Foil stall meter - idea
« Reply #12 on: April 15, 2019, 10:08:53 AM »
I call that "suck, then bang."
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Piros

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Re: Foil stall meter - idea
« Reply #13 on: April 15, 2019, 03:47:46 PM »
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