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A² foil sailing

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Created by seanhogan > 9 months ago, 7 Jan 2013
seanhogan

seanhogan

QLD, 3424 posts
7 Jan 2013 12:54PM
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izaak

izaak

TAS, 2013 posts
7 Jan 2013 3:17PM
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Awesome!! This Will be the only way, at this present time. To have a chance to break the world record. I would love to have a go, on the foil.

doggie

doggie

WA, 15849 posts
7 Jan 2013 12:24PM
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WOW!! That was super cool

So smooth

djl070

djl070

WA, 290 posts
7 Jan 2013 1:55PM
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It appears to be one of Rush Randles boards,he has been experimenting with hydrofoils for a number of years,it looks like awesome fun

CJW

CJW

NSW, 1726 posts
7 Jan 2013 6:46PM
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izaak said...
Awesome!! This Will be the only way, at this present time. To have a chance to break the world record. I would love to have a go, on the foil.


Won't happen, i'd be surprised if they could even get near 30kts with a foil like that. While certainly cool, they are pretty much a novelty and no windsurfer resembling anything close to what we have now will break the new world speed record, the bar is set that high.

doggie

doggie

WA, 15849 posts
7 Jan 2013 4:05PM
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CJW said...
izaak said...
Awesome!! This Will be the only way, at this present time. To have a chance to break the world record. I would love to have a go, on the foil.


Won't happen, i'd be surprised if they could even get near 30kts with a foil like that. While certainly cool, they are pretty much a novelty and no windsurfer resembling anything close to what we have now will break the new world speed record, the bar is set that high.


But wouldnt there be less drag with this type foil CJW?

AusMoz

AusMoz

QLD, 1498 posts
7 Jan 2013 8:52PM
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What speed have they recorded with this set up?

Dartboy

Dartboy

VIC, 172 posts
7 Jan 2013 10:31PM
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Do they make it in a Weed version ?

terminal

terminal

1421 posts
7 Jan 2013 7:47PM
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The French seem to be leading the way on foil development, but the main application seems at the moment to be light wind.

AHD seem to be developing a board for sale.

terminal

terminal

1421 posts
7 Jan 2013 7:59PM
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Sailrocket has quite a windsurfer-like design, so a variation of it would be what I would think would be the fastest. Sailrocket was designed almost without design restrictions, so it would be very hard to beat - especially if they scale it up.

The only advantage a windsurfer might bring would be quicker reactions and more sensitivity.

We still need to see how far the current design of windsurfer can go as they are going much faster than the windspeed now in 40 knots of wind, and we need to see what a windsurfer can do in 50 to 60 knots of wind.

Sailrocket is much more efficient, going at perhaps 2+ times the speed of the wind, so will get many more opportunities to set new records than if needing to wait for 60 knots.

terminal

terminal

1421 posts
7 Jan 2013 8:04PM
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A foil going quite quick. I think this guy has done about 35 knots on one - but I think he was using straps when he did that.

CJW

CJW

NSW, 1726 posts
7 Jan 2013 11:59PM
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terminal said...
Sailrocket has quite a windsurfer-like design, so a variation of it would be what I would think would be the fastest. Sailrocket was designed almost without design restrictions, so it would be very hard to beat - especially if they scale it up.

The only advantage a windsurfer might bring would be quicker reactions and more sensitivity.

We still need to see how far the current design of windsurfer can go as they are going much faster than the windspeed now in 40 knots of wind, and we need to see what a windsurfer can do in 50 to 60 knots of wind.

Sailrocket is much more efficient, going at perhaps 2+ times the speed of the wind, so will get many more opportunities to set new records than if needing to wait for 60 knots.


The genius of Sailrocket is how the force from the sail is reacted into the foil, they have totally eliminated righting moment from the equation. This enables them to hold down massive amounts of power = overcoming drag. Their biggest issue is foil cavitation which they seem to be on top of.

Neither a windsurfer or a kite has this luxury and in both of their current forms it's just not possible to compete purely on a power/drag basis. Kites and windsurfers are both at this point chasing efficiency, which is why we have seen such small incremental improvements, but the laws of diminishing returns are already well in play, imo of course.

terminal

terminal

1421 posts
7 Jan 2013 9:44PM
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CJW said...
terminal said...
Sailrocket has quite a windsurfer-like design, so a variation of it would be what I would think would be the fastest. Sailrocket was designed almost without design restrictions, so it would be very hard to beat - especially if they scale it up.

The only advantage a windsurfer might bring would be quicker reactions and more sensitivity.

We still need to see how far the current design of windsurfer can go as they are going much faster than the windspeed now in 40 knots of wind, and we need to see what a windsurfer can do in 50 to 60 knots of wind.

Sailrocket is much more efficient, going at perhaps 2+ times the speed of the wind, so will get many more opportunities to set new records than if needing to wait for 60 knots.


The genius of Sailrocket is how the force from the sail is reacted into the foil, they have totally eliminated righting moment from the equation. This enables them to hold down massive amounts of power = overcoming drag. Their biggest issue is foil cavitation which they seem to be on top of.

Neither a windsurfer or a kite has this luxury and in both of their current forms it's just not possible to compete purely on a power/drag basis. Kites and windsurfers are both at this point chasing efficiency, which is why we have seen such small incremental improvements, but the laws of diminishing returns are already well in play, imo of course.


The elimination of righting moment is a good thing in that its the resistance of the foil that is key, so you dont need the weight of the rider to be hiked out on an outrigger - in theory.
The problems will be:-

That to streamline, the rider has to lie down. The only alternative might be to have him inside the luff of the sail and control it from there.
There is such an idea already, and the sail size can be increased to maybe 20m because the rider doesn't have to hold it down.



The rider has to control the sail and the foil and he will be somewhere in between the two (or in the luff).

How to get the thing planing in the first place.

terminal

terminal

1421 posts
7 Jan 2013 10:59PM
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I think this guy is saying that he has developed a self-regulating foil that maintains its depth. It might be possible to have a way of auto-control for the foil so the widsurfer only has to steer the board and sheet the sail.
Something like the old Starboard Supersonic 90l might work as the hull as it should ride on a cushion of air at speed?

evlPanda

evlPanda

NSW, 9207 posts
8 Jan 2013 2:46PM
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^ I've always had this idea for a kite attached to a buoy. Person rides somewhere on the line, in the air.

[bubble bubble bubble]

da vecta

da vecta

QLD, 2515 posts
8 Jan 2013 2:05PM
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evlPanda said...
^ I've always had this idea for a kite attached to a buoy. Person rides somewhere on the line, in the air.

[bubble bubble bubble]


Wow that would be a sick long boost dude.

Sailhack

Sailhack

VIC, 5000 posts
8 Jan 2013 3:22PM
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terminal said...
I think this guy is saying that he has developed a self-regulating foil that maintains its depth.


If you've ever trolled a large lure, that's how they work. I can't lift some of my lures (large bibbed ones) out of the water until they are beside the boat & the line is basically vertical. I don't see anything special about that unless of course the element of drag is reduced.

As for the other vids (flamesuit on) - I might be wrong but that looks as boring as bat sh!t! All riders look as though they are too busy concentrating on managing the foil & sail/kite. Nothing beats planing with the feeling of the water skipping under the board and hitting the odd ramps. If you want that elevated feeling, whack on a flexible 50cm fin in overpowered conditions - you'll soon be lifted above the water.

terminal

terminal

1421 posts
8 Jan 2013 6:41PM
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I cant see there being any sponsorship money from within windsurfing to make a windsurfing version of Sailrocket and foils just seem to be more suited to kiting than windsurfing.

Its an interesting variation to experiment with and some kind of breakthrough may come from it but it hasn't got much appeal at the moment.

evlPanda

evlPanda

NSW, 9207 posts
9 Jan 2013 4:59PM
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Sharks are known as extremely fast and agile swimmers, due in part to the surface of their skin. Sharks are covered in very tiny tooth-shaped scales called denticles which are streamlined in the direction of flow over the shark. If you were to run a hand over a shark's skin from head to tail, it would feel silky smooth, but rub against the grain and it's like running your hand on sandpaper.

Water encounters a similar resistance, which, according to new research, provides the shark with a passive flow control mechanism, requiring no effort on the part of the shark. When water near the shark's denticles tries to reverse direction, an early stage in flow separation, the denticles naturally bristle, slowing and trapping the reversed flow. This prevents local flow separation which would otherwise increase the shark's drag and hinder its agility. (Photo credit: James R. D. Scott; Research by A. Lang et al.)




Where's my shark skin fin, or sail for that matter?
(...god I'm indignant sounding prick. What I mean is has anyone done any research on it, is it even feasible?)

terminal

terminal

1421 posts
9 Jan 2013 6:59PM
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terminal said...
I think this guy is saying that he has developed a self-regulating foil that maintains its depth. It might be possible to have a way of auto-control for the foil so the widsurfer only has to steer the board and sheet the sail.
Something like the old Starboard Supersonic 90l might work as the hull as it should ride on a cushion of air at speed?




This could be a fairly easy system to try out.

The windsurfer ties the foil onto the back of his harness and in theory, he can hold a lot more power then. I think the guy in the video is saying he is measuring 40kg of pull from the foil, and it wasn't going that fast.

He shouldn't need the fin then other than to provide some directional stability to the board, so it wouldn't need to have lift and could be a flat blade.

The board maybe wouldn't need to touch the water and might be able to ride on a cushion of air (like the Starboard Supersonic) but thats a big maybe and depends on the lift of the sail, the riders weight and how stable a board on a cushion of air would be.


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"A² foil sailing" started by seanhogan



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