Author Topic: Zen Downwind???  (Read 1442 times)

PonoBill

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Zen Downwind???
« on: August 15, 2021, 09:15:14 AM »
I saw something during the Gorge Paddle Challenge down-wing foil race that I don't understand at all. The leader, one of the spencer kids, either Jeff or Finn, went by going straight downwind with his wing drawing like he was doing a beam reach. He was leaning back into the pull and visibly sheeting in with sort of a slow pump.

I was on more or less the same line with my wing almost flagged out, going fast for me, which is about half as fast as he was going. If I'd been going as fast as he was my wing would have been hanging down or even backwinded. HTF did he DO that?

No, I wasn't dueling with him for the lead, I wasn't racing. I rode upwind to the hatchery to follow the racers in and see how this stuff should be done. Instead, I just have a big old puzzle. Does he have some deal with the gods of wind? Is this some kind of apparent wind thing that I don't understand at all? Zen?? Is a motor involved?

The next four places were doing sort of the same thing, though not as fast, then came everyone else, doing more or less what I was--as broad a reach as they could to keep their wing flying, and riding the bumps for speed. I asked Livio about it (he finished fifth) but I didn't really understand what he told me.
« Last Edit: August 15, 2021, 09:29:53 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.

Dontsink

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Re: Zen Downwind???
« Reply #1 on: August 15, 2021, 10:41:02 AM »
That is interesting.
This is the polar for an AC75 Americas Cup boat.Max VMG downwind at 153* off the true wind.
This wingfoilers  were going straight downwind,like 180* off the wind?.How much was it blowing?

Dontsink

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Re: Zen Downwind???
« Reply #2 on: August 15, 2021, 01:54:56 PM »

daswusup

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Re: Zen Downwind???
« Reply #3 on: August 15, 2021, 02:42:56 PM »
Its a Dart thing. I can surf on lake chop going straight downwind with my Dart. It was not possible on any regular shaped wings. I am constantly baffled why all of you are not on Darts???? They are sooooo good. Not just for backflips. They are for doing shit that you can't do on other wings. Straight upwind, straight downwind. Acceleration like no other. The jumping is all time. Most who try them never go back. Tony is a frigging wing wizard. He just totally made up for the Slingwing V1.

Dontsink

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Re: Zen Downwind???
« Reply #4 on: August 15, 2021, 02:57:56 PM »
Its a Dart thing. I can surf on lake chop going straight downwind with my Dart. It was not possible on any regular shaped wings. I am constantly baffled why all of you are not on Darts???? They are sooooo good. Not just for backflips. They are for doing shit that you can't do on other wings. Straight upwind, straight downwind. Acceleration like no other. The jumping is all time. Most who try them never go back. Tony is a frigging wing wizard. He just totally made up for the Slingwing V1.

You got GPS tracks of this?.
I am curious as to what angles you can get Upwind and Downwind on the Dart.
The sweptback shape is the obvious difference to other designs,i would like to try one.

PonoBill

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Re: Zen Downwind???
« Reply #5 on: August 15, 2021, 04:11:23 PM »
Its a Dart thing. I can surf on lake chop going straight downwind with my Dart. It was not possible on any regular shaped wings. I am constantly baffled why all of you are not on Darts???? They are sooooo good. Not just for backflips. They are for doing shit that you can't do on other wings. Straight upwind, straight downwind. Acceleration like no other. The jumping is all time. Most who try them never go back. Tony is a frigging wing wizard. He just totally made up for the Slingwing V1.

He wasn't on a dart for the downwinder. I don't think any of the leaders were.  They looked good in the course race, but the kid that won was more than half a lap ahead on an F-one Strike.
« Last Edit: August 15, 2021, 04:15:33 PM 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.

surfcowboy

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Re: Zen Downwind???
« Reply #6 on: August 16, 2021, 05:59:33 PM »
Signing up for Alan Cadiz Patreon. Letís all do it and ask him.


Salish Salt

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Re: Zen Downwind???
« Reply #7 on: September 26, 2021, 10:54:30 PM »
Physics of going straight down wind faster than the wind.
"Any Speed is possible ... if ... and gear ratios"

https://www.youtube.com/watch?v=jyQwgBAaBag&t=1s

https://www.youtube.com/watch?v=yCsgoLc_fzI
« Last Edit: September 26, 2021, 11:06:44 PM by Salish Salt »

Beasho

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Re: Zen Downwind???
« Reply #8 on: September 27, 2021, 06:24:25 PM »
In the early 90's in Engineering school there was a water tank with a windmill powered catamaran.

The small 18" model was placed in a water tank and then a fan started.  The boat was pointing into the wind. 

The boat jogged backward when hit with the wind then the windmill started turning.  There was a pulley attached to a propeller.

The boat then proceeded to move forward into the wind, straight into the wind and then started accelerating. I wouldn't have believed it if I hadn't seen it.
 
Essentially it was a version of those propeller craft both full scale and the model sized prototypes.   

« Last Edit: September 27, 2021, 06:28:35 PM by Beasho »

PonoBill

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Re: Zen Downwind???
« Reply #9 on: September 27, 2021, 06:52:32 PM »
I think that "physics prof" needs a substantial refresher course. The math is fairly straightforward, and the underlying principle is the radical difference in the two mediums. Water is 1000 times denser than air. You can treat a propeller in water as if it were a screw in wood--the water does not compress, if you can turn the screw it will move forward. Using wind to turn the screw is ridiculously easy. Once the platform is moving, the forward motion increases the apparent wind. Duh. There are a few experimental sailcraft in the world that use wind turbines to spin propellors. They can move at speed, directly into the wind.

Same thing with a car on land. Unless the tires are slipping, turning them moves the car forward. Going directly into the wind is easy, and the faster you go, the more wind is available.

No, you can't do that with an airplane. The medium the airplane is trying to travel through is also what is spinning the propellor.

I've experienced "physics profs" that dense before, though my natural skepticism tells me this is a youtube setup--a little drama for an otherwise unremarkable thing. But teachers of physics are not the same thing as physicists--they get some basic understanding of Newton and the laws of thermodynamics 30 years ago and consider their requirement for actually thinking something through was fulfilled at some point back in college. They will tell you over and over that the only thing that determines friction is the normal force and the coefficient of friction of the material, ignoring the fact that even the classical inclined plane experiment that "proves" that principle shows small surface area differences consistently--and the "error" is always in the direction of greater surface area. How dense does anyone need to be? Yeah, and that's why dragsters use bicycle tires instead of huge slicks. But I digress.
« Last Edit: September 27, 2021, 07:03:40 PM 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.

Dontsink

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Re: Zen Downwind???
« Reply #10 on: September 27, 2021, 08:38:45 PM »
I think that "physics prof" needs a substantial refresher course. The math is fairly straightforward, and the underlying principle is the radical difference in the two mediums. Water is 1000 times denser than air. You can treat a propeller in water as if it were a screw in wood--the water does not compress, if you can turn the screw it will move forward. Using wind to turn the screw is ridiculously easy. Once the platform is moving, the forward motion increases the apparent wind. Duh. There are a few experimental sailcraft in the world that use wind turbines to spin propellors. They can move at speed, directly into the wind.

Same thing with a car on land. Unless the tires are slipping, turning them moves the car forward. Going directly into the wind is easy, and the faster you go, the more wind is available.

No, you can't do that with an airplane. The medium the airplane is trying to travel through is also what is spinning the propellor.

I've experienced "physics profs" that dense before, though my natural skepticism tells me this is a youtube setup--a little drama for an otherwise unremarkable thing. But teachers of physics are not the same thing as physicists--they get some basic understanding of Newton and the laws of thermodynamics 30 years ago and consider their requirement for actually thinking something through was fulfilled at some point back in college. They will tell you over and over that the only thing that determines friction is the normal force and the coefficient of friction of the material, ignoring the fact that even the classical inclined plane experiment that "proves" that principle shows small surface area differences consistently--and the "error" is always in the direction of greater surface area. How dense does anyone need to be? Yeah, and that's why dragsters use bicycle tires instead of huge slicks. But I digress.

Er...i would watch the vid again Ponobill.

This sailcraft is way more complex than what you are describing.
It goes straight downwind faster than the wind,quite revolutionary,never been done before and believed to be impossible by very learned people.

It starts moving downwind the way you describe,wind turns propeller which spins the wheels,faster you go the less apparent wind it gets,but at a certain speed relative to the wind they "switch" the propellers angle of incidence and the wheels spin the propeller to create thrust...and they push through the windspeed.
It is quite brilliant.

PonoBill

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Re: Zen Downwind???
« Reply #11 on: September 28, 2021, 06:21:26 PM »
Yeah, I should probably pay more attention to the actual video. I got distracted. Surprise, surprise.
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.

 


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