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      A Few Simple Rules   05/22/2017

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Alakaluf

WOW - Oracle AC45 with foils !

372 posts in this topic

Scoop !

Want to see Oracle's AC45 sailing - flying - with foils ?

Just here :

 

http://www.voilesetv...usse-des-foils/

 

Enjoy !

HH / Voiles et Voiliers

 

After the wings, the stilts! On Monday morning, from 0:01, you're the first to discover the crazy idea of defending American Cup: put the foils in the floats of its AC45! Result: totally insane speeds, as evidenced by the bending of the leeward foil - yet carbon. The drift-foils, which have been advanced, are "L" returning, rudder, "T" inverted. But, difficult to master, these appendices will they be placed under the AC72 future? / H.H.

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that's high and looks nicely in control

 

some serious forces on at the bend of the 1 L foil holding everything up

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Nice, the bottom of the L looks like 1 Spitfire wing. The engineering at the intersection of the L must be something special. I wonder how they are controlling the pitch angle on the board, as it doesn't look like they are adjusting it on this one - just the standard AC 45 setup. Fascinating - don't see the t foil rudder pitch control either, but it is a far away shot. Nice scoop.

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Is that for real?

 

Any way that it could have been photoshopped?

 

Any confirmation from inside sources about this experiment?

 

I don't know anything about hydrodynamics, except for one thought about Froude numbers and the difficulties of reasoning from tank testing to full-size boats. For those who do know about foils, does this "look right"? Could such small foils really lift an AC45 like that?

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That boat has that funky pod thingy in the wing, too.

 

Here is a link to a post by you know who in Feb this showing this Linky.

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I wonder how they are controlling the pitch angle on the board, as it doesn't look like they are adjusting it on this one - just the standard AC 45 setup. Fascinating - don't see the t foil rudder pitch control either, but it is a far away shot. Nice scoop.

 

The AC72 class rule prohibits adjustable foil surfaces while sailing, except for a weed knife.

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Is that for real?

 

Any way that it could have been photoshopped?

 

Any confirmation from inside sources about this experiment?

 

I don't know anything about hydrodynamics, except for one thought about Froude numbers and the difficulties of reasoning from tank testing to full-size boats. For those who do know about foils, does this "look right"? Could such small foils really lift an AC45 like that?

no need to photo shop that, it's been done before. i won't say it's easy, but it ain't rocket science.

 

Good job though for OR, looks fly

 

B

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Is that for real?

 

Any way that it could have been photoshopped?

 

Any confirmation from inside sources about this experiment?

 

I don't know anything about hydrodynamics, except for one thought about Froude numbers and the difficulties of reasoning from tank testing to full-size boats. For those who do know about foils, does this "look right"? Could such small foils really lift an AC45 like that?

 

A video would confirm it but I suspect that the shot was taken as the AC45 launched off a wave. I don't believe it is 'foiling'.

 

We have seen pictures the 'L' foil and 'T' rudder on the AC45 back in Feb so nothing new here.

 

We have also seen pictures of TNZ testing SL33's with 'L' foils and 'T' rudders.

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Is that for real?

 

Any way that it could have been photoshopped?

 

Any confirmation from inside sources about this experiment?

 

I don't know anything about hydrodynamics, except for one thought about Froude numbers and the difficulties of reasoning from tank testing to full-size boats. For those who do know about foils, does this "look right"? Could such small foils really lift an AC45 like that?

Not likely PhotoShop. Truly outstanding piece of work if it is. And of course earlier pix show the L-foil. Anyway a video sequence will provide convincing evidence, hence my earlier comment.

 

As an interested sailor I've followed sailing foil developments fairly closely over a couple of decades but I claim no technical knowledge of performance. Lifting with a small foil like that is not the problem if you have sufficient power to weight ratio. The problem as others have noted is control.

 

It is intriguing that one really good photo should suddenly pop up, virtually out of the blue, and from a French source at that.

 

 

^^ Edit: I'm inclined to accept k_j's explanation.

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I suspect all -- well, perhaps not all -- will be revealed in Newport, RI on Monday afternoon, 25th June. Oracle is holding one of its group interviews for invited media. Agenda includes Newport plus news from the training and testing session that just finished in San Francisco.

 

JS, JK and Dirk Kramers will be on the stage. It kicks off at 1100 hours local time.

 

I'll hazard a guess that the photo was a clever PR plant to drum up interest. No outside photographer would get that close to the boat while it was actively testing.

 

Perhaps we'll also learn about the pod in the wing!

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Scoop !

Want to see Oracle's AC45 sailing - flying - with foils ?

Told you so.

http://forums.sailin...pic=65730&st=50

 

That is the most royally bitchin video! It sure seems like the big boats are eating up the small boats.

 

But I keep getting back to the question of whether or not length even matters in this race.

 

So this is for the smart people who understand the equations. At some point, isn't a boat's waterline length irrelevant, and isn't a 90 foot multihull well past that point?

 

Here's my thinking. Ninety feet wide is more than enough platform to carry as large a sail plan as humanly controllable. This means that under just about any wind conditions the boat could power up and pop out of the water or skip along the top of it. If a boat is planing or foiling then a very small fraction of its hull is in the water. Right? Therefore, who cares whether a boat has 115' in the water for measurement or not, it just doesn't matter. It's power and weight and lift and reliability and maybe even sailing.

 

Koukel

 

Koukel

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I suspect all -- well, perhaps not all -- will be revealed in Newport, RI on Monday afternoon, 25th June. Oracle is holding one of its group interviews for invited media. Agenda includes Newport plus news from the training and testing session that just finished in San Francisco.

 

JS, JK and Dirk Kramers will be on the stage. It kicks off at 1100 hours local time.

 

I'll hazard a guess that the photo was a clever PR plant to drum up interest. No outside photographer would get that close to the boat while it was actively testing.

 

Perhaps we'll also learn about the pod in the wing!

 

 

LA PHOTO À LA HUNE par Guilain Grenier (Oracle Team USA)

 

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Pod = Gyro system for the foils?

 

But why would they give away some secrets this early? Something to goose-up the 45's?

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Pod = Gyro system for the foils?

 

But why would they give away some secrets this early? Something to goose-up the 45's?

If the foil is good, it's likely a no brainer, right?

 

Koukel

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Pod = Gyro system for the foils?

 

But why would they give away some secrets this early? Something to goose-up the 45's?

 

Holy Hell, that would be an entirely new thing to think about. How many grinders committed to full-time spinning a gyro to keep boat flat? IF that is going on. Pretty big "IF", but we are really sailing uncharted waters, here.

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Pod = Gyro system for the foils?

 

But why would they give away some secrets this early? Something to goose-up the 45's?

 

Holy Hell, that would be an entirely new thing to think about. How many grinders committed to full-time spinning a gyro to keep boat flat? IF that is going on. Pretty big "IF", but we are really sailing uncharted waters, here.

 

Well, I did not see the little wand like the Moths, etc, use to adjust the angle so I thought gyro. But maybe too far out there?

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I'm a little suspicious-the lee daggerboard looks too far above deck, for one thing, and for another where is the altitude control system(wand), or is it manual or electronic? One things for sure there has to be one because those are fully submerged foils......

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When you say gyro do you mean a small one for measuring the inclination or a masssive one to actually keep the boat level?

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When you say gyro do you mean a small one for measuring the inclination or a masssive one to actually keep the boat level?

 

I believe he was thinking the latter. That Pod thingy has been a mystery, and you certainly would not need something of that size for the former. I think the very idea of a gyro in this context is WAY out there, but I'm certainly not going to say it is impossible. Something would have to keep that boat flat, and in the absence of some form of elevator on the rudder, which is not allowed, this could be an option. Would a gyro effect be strong enough for this type of situation, and would it also make turning the boat a bitch? I am not seeing the point of having it incorporated into the wing, though, but it would not be first time that I could not get the point at first.

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Is that for real?

 

Any way that it could have been photoshopped?

 

Any confirmation from inside sources about this experiment?

 

I don't know anything about hydrodynamics, except for one thought about Froude numbers and the difficulties of reasoning from tank testing to full-size boats. For those who do know about foils, does this "look right"? Could such small foils really lift an AC45 like that?

Not likely PhotoShop. Truly outstanding piece of work if it is. And of course earlier pix show the L-foil. Anyway a video sequence will provide convincing evidence, hence my earlier comment.

 

As an interested sailor I've followed sailing foil developments fairly closely over a couple of decades but I claim no technical knowledge of performance. Lifting with a small foil like that is not the problem if you have sufficient power to weight ratio. The problem as others have noted is control.

 

It is intriguing that one really good photo should suddenly pop up, virtually out of the blue, and from a French source at that.

 

 

^^ Edit: I'm inclined to accept k_j's explanation.

 

 

This is all going according to plan :) There is always a method to Larry's madness :)

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I suspect that the shot was taken as the AC45 launched off a wave. I don't believe it is 'foiling'.

To my eye, there is no evidence that the boat was captured as it launched off of a wave:

 

1.- There is no wave in the photo

2.- There is no splash or spray coming off of the hulls as one would expect if they had just been flung off the top of a wave.

3.- The roostertail coming off the starboard foil is long and uniform in shape and looks as if the boat had been travelling in that attitude for some time.

4. The crew do not look as if the boat had suddenly been thrown four or five feet into the air. They look as if they are relatively comfortable and in control, not hanging on for dear life.

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I really hope this is what their 72 looks like! Although now if one aims at one day competing in the cup, do they train in moths or cats?

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I wonder how they are controlling the pitch angle on the board, as it doesn't look like they are adjusting it on this one - just the standard AC 45 setup. Fascinating - don't see the t foil rudder pitch control either, but it is a far away shot. Nice scoop.

 

The AC72 class rule prohibits adjustable foil surfaces while sailing, except for a weed knife.

 

We won't see this on an AC72. But it seems to me if you can make it work on an AC45 you would have a boat you could train on at the speeds of (or at least close to ) the AC72's. Good plan in my book.

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Is that for real?

 

Any way that it could have been photoshopped?

 

Any confirmation from inside sources about this experiment?

 

I don't know anything about hydrodynamics, except for one thought about Froude numbers and the difficulties of reasoning from tank testing to full-size boats. For those who do know about foils, does this "look right"? Could such small foils really lift an AC45 like that?

 

A video would confirm it but I suspect that the shot was taken as the AC45 launched off a wave. I don't want to believe it is 'foiling'.

 

We have seen pictures the 'L' foil and 'T' rudder on the AC45 back in Feb so nothing new here.

 

We have also seen pictures of TNZ testing SL33's with 'L' foils and 'T' rudders.

Corrected.

 

Maybe GD has a few similar shots of TNZ then.

 

 

 

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The reaction by some to these pictures is actually a lot more entertaining than the foiling itself. "It's photo shopped", "I don't believe it", "they were launched off a wave". I think Max got it right, at least for some of the crowd here. I'd expect some are laughing their asses off over the reception here.

 

If I'm not mistaken, they ran similar experiments with USA17 as part of the AC33 development process, and LE actually spoke about it at one of the Oracle World conferences in 2009 before they won the cup. I recall watching the video and his amazement in speaking of the accomplishment given the scale of the boat.

 

I suppose it's possible with the AC72's for the cup, but it might be a "bet the campaign" decision as if the foil snapped under the loads you'd be out, at least for that race.

 

That's the great thing about OR - their R&D goes far beyond what the actual event allows or even calls for. I witnessed this first hand in San Diego just before the wing was announced, to the surprise of many on the Alinghi team and all their SD spies. They had a ton of development going on that they knew they couldn't use in AC33 for different reasons - some rules, other technology maturity, but they did the research regardless to find the limits of the current generation of technologies as well as the next generation of technology.

 

Not much different than what it takes to maintain your success in the the business I'm in. Being status quo doesn't cut it for very long. Look over your shoulder and you're likely to get run down.

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Wonderful pictures, amazing.

It seems that the foil is very well placed as the boat seems very well balanced.

IMO, the foil is a bit too down and the boat a bit too high considered the state of the sea. The higher the boat the less power, however we don't have the full sequence.

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Well, I did not see the little wand like the Moths, etc, use to adjust the angle so I thought gyro. But maybe too far out there?

 

It could be using a sonar to determine how high out of water they are, I have tinkered a little with one on my Moth and it could be quite effective if battery life and class rules weren't an issue

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Alt_GG12SFOJUN33121.jpg

 

the dagger length fishiness doug commented on in the earlier shot

 

is even more apparent in this pic...

 

do we know how they lock the dagger down enough to support the boats weight like that?

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Lifting with a small foil like that is not the problem if you have sufficient power to weight ratio. The problem as others have noted is control.

 

I agree on both. If Mirabaud can foil I don't see why an AC45 could not. What we may be seeing here is some development of technology that - unlike wings - will feed back into general high performance sailing. That would be interesting.

 

For those who have never been near a foiling Moth, what's spooky is not only that they are going so fast but that it is almost silent. You don't see them coming because they sail completely different angles but you don't hear them coming either. Fortunately they recognise they've just got to avoid the rest of us!

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That's some serious sailing! I am having a hard enough time believing that L foil can hold up the AC45, much less that they have a gyro that keeps the thing going level. Whatever they are doing, I can't wait to see it in action on the AC72. I am skeptical that it will end up on a boat that the rest of us can purchase and sail.

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^

 

You can purchase a foiling Moth off the shelf today so I don't see what's so hard to believe about trickle-down of technology. Whether you could sail one I couldn't say. I know some Mothists and persistence and fitness are certainly requirements.

 

If Mirabaud can foil in not very much wind I'm not sure why you believe an AC45 could not do so in SF conditions.

 

Of course the terrible thing about this development is that Doug Lord will be hitting SAAC.

 

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Buuuuttt... Mirabaud doesn't have L-boards, much less a giro.

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That's some serious sailing! I am having a hard enough time believing that L foil can hold up the AC45, much less that they have a gyro that keeps the thing going level. Whatever they are doing, I can't wait to see it in action on the AC72. I am skeptical that it will end up on a boat that the rest of us can purchase and sail.

They where testing the boards on the AHPC C2-F18 (Bundock is their European distributor).

Although a bit impractical for launching of the beach it is certainly not impossible.

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That is a VIPER not a C2. I believe they were testing the L-foils as an answer to the curved foils of the Nacra17. I don't think the intention was to ever 'foil' just to provide lift

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Because there is no wand, Doug is a disbeliever, it can't happen, Photoshop trickiness, therefore it is all phony and doesn't exist in real world. He has wiped his hands of this fantasy, not saying he won't be posting though. Plenty of foilers fly without actuating flaps and wands. look at Hydroptere for a king example. Also the comments about the great length of the lee daggger/foil and that only half the depth is being used, well, the platform is flying very high anyway ... and the dagger/L should be lifted further, imo. But what do I know, maybe the crew experiencing the reality feel the foiling at this height is the best balance and equilibrium. Also, in lighter airs, they would want the full depth because ... blah, blah, you all know the reasons. Likening this configuration with Off yer rocker is not correct; OYR had four deep foils dragging all the time, hence its lack of speed; this AC45 is sailing in the fresh wind, with only two foils working - okay the windward T rudder will be down some of the time but mostly wetted surface area there is low.

This is all good ... and those T rudders will stop the hyper powerful AC45's from going arse over head so frequently - that is, if this setup is legalised. Maybe the rulemakers will see the light and change. Foiling sailors pointed out this save your ass design setup months/years ago.

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I wonder how they are controlling the pitch angle on the board, as it doesn't look like they are adjusting it on this one - just the standard AC 45 setup. Fascinating - don't see the t foil rudder pitch control either, but it is a far away shot. Nice scoop.

 

The AC72 class rule prohibits adjustable foil surfaces while sailing, except for a weed knife.

 

We won't see this on an AC72. But it seems to me if you can make it work on an AC45 you would have a boat you could train on at the speeds of (or at least close to ) the AC72's. Good plan in my book.

 

 

 

 

We may not see these exact foils on the AC72 but you can rest assured that there will be some very similar foils out there.. These, among others, are the type of things that will win the cup for whoever has the clackers to think outside the square..

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............. look at Hydroptere for a king example. Also the comments about the great length of the lee daggger/foil and that only half the depth is being used, well, the platform is flying very high anyway ... and the dagger/L should be lifted further, imo. But what do I know, ................................... Foiling sailors pointed out this save your ass design setup months/years ago.

 

may I suggest, Coxcreek.... you know more than most lurking these forums and a shit load more than just about everyone who posts comments.

 

So, what's in the wing bubble?

post-31389-055836100 1340617848_thumb.jpg

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i don't think the bubble can be a gyro to stabilize the boat

 

for that the gyro would have to be very heavy and mounted on the boat not the wing

 

are there side views?

 

could it be camouflaging hydraulic rams?

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There are more photos on Sail World. Impossible to tell from the photos whether foiling is sustainable, but the amount of leeward heel is not good. The leeward foil loads up hugely in this attitude, you never see a Moth foiling to windward with leeward heel. They capsize.

 

Some leeward heel is manageable downwind, but only because the apparent is very much less and it can be controlled. Moths usually sail very flat downwind because that's fastest, with maybe a little leeward heel as it means going deeper (but slower).

 

I would think the ideal attitude would be with the windward hull just touching the water and the leeward hull well clear. Far less load on the foil and much easier to balance, but tough to manage in such a large boat. The mainsheet trimmer will be working overtime and in perfect harmony with the helm.

 

As for pitch control, it can be best done using rake on the rudder, only small angular changes are required. Altitude adjustment is a puzzle, maybe it's manual. One method is to bleed air onto the lifting surface to reuduce lift. Dunno how efficient that is though. Maybe there's a rake control on the c/b to change the angle of attack and hence lift. It would be a very fine line to get it right though, a flap is much more controllable.

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As for pitch control, it can be best done using rake on the rudder, only small angular changes are required.

rake on a rudder with a fixed T foil

 

is going to be problematic...

 

the standard ac45 rudders come up from the bottom don't they?

 

any rake system back there would probably be too extensive to allow the boat to stay in the acws

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............. look at Hydroptere for a king example. Also the comments about the great length of the lee daggger/foil and that only half the depth is being used, well, the platform is flying very high anyway ... and the dagger/L should be lifted further, imo. But what do I know, ................................... Foiling sailors pointed out this save your ass design setup months/years ago.

 

may I suggest, Coxcreek.... you know more than most lurking these forums and a shit load more than just about everyone who posts comments.

 

So, what's in the wing bubble?

 

Crash pads for when the foils stop lifting and they go a-over!

 

I actually think they might be look-ahead sonar/wind instruments - totally unrelated to the foiling and more to do with predicting the wind up the course.

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As for pitch control, it can be best done using rake on the rudder, only small angular changes are required.

rake on a rudder with a fixed T foil

 

is going to be problematic...

 

the standard ac45 rudders come up from the bottom don't they?

 

any rake system back there would probably be too extensive to allow the boat to stay in the acws

 

 

Not the hulls they are using in the acws, they have 4 of them, but the surrogacy rules 'should' be taking care of these sort of mods I believe.

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............. look at Hydroptere for a king example. Also the comments about the great length of the lee daggger/foil and that only half the depth is being used, well, the platform is flying very high anyway ... and the dagger/L should be lifted further, imo. But what do I know, ................................... Foiling sailors pointed out this save your ass design setup months/years ago.

 

may I suggest, Coxcreek.... you know more than most lurking these forums and a shit load more than just about everyone who posts comments.

 

So, what's in the wing bubble?

 

Crash pads for when the foils stop lifting and they go a-over!

 

I actually think they might be look-ahead sonar/wind instruments - totally unrelated to the foiling and more to do with predicting the wind up the course.

 

again you'd be better on the main beam due to wing rotation

 

but maybe the wing if they want to keep the boat in the acws...

 

 

 

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Alt_GG12SFOJUN33121.jpg

 

the dagger length fishiness doug commented on in the earlier shot

 

is even more apparent in this pic...

 

do we know how they lock the dagger down enough to support the boats weight like that?

 

The round Gennaker does not match with the supposed speed in my eyes. Should have collapsed. Something is fishy also with the length (different?) of the daggerboards. uuhps, corrected: It is the pole which is being used for raising and lowering which distracted my eyes.

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Don't mix the dagger boards up with the lifting post in front of them.

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Don't mix the dagger boards up with the lifting post in front of them.

good point, there is a lump halfway down the pole that must be the top of the board

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Because there is no wand, Doug is a disbeliever, it can't happen, Photoshop trickiness, therefore it is all phony and doesn't exist in real world. He has wiped his hands of this fantasy, not saying he won't be posting though. Plenty of foilers fly without actuating flaps and wands. look at Hydroptere for a king example. Also the comments about the great length of the lee daggger/foil and that only half the depth is being used, well, the platform is flying very high anyway ... and the dagger/L should be lifted further, imo. But what do I know, maybe the crew experiencing the reality feel the foiling at this height is the best balance and equilibrium. Also, in lighter airs, they would want the full depth because ... blah, blah, you all know the reasons. Likening this configuration with Off yer rocker is not correct; OYR had four deep foils dragging all the time, hence its lack of speed; this AC45 is sailing in the fresh wind, with only two foils working - okay the windward T rudder will be down some of the time but mostly wetted surface area there is low.

This is all good ... and those T rudders will stop the hyper powerful AC45's from going arse over head so frequently - that is, if this setup is legalised. Maybe the rulemakers will see the light and change. Foiling sailors pointed out this save your ass design setup months/years ago.

======================

I wondered about it being photoshopped but I no longer think thats the case after seeing the series of photos on Sail-World. But one things for sure: these are fully submerged foils-not surface piercing foils(that automatically adjust their altitude)-they MUST have some form of altitude control by all that is holy. If you took a Rave or an Osprey and ripped off the wands I can gurantee you that the boat wouldn't fly for long. However, the Rave was flown by two different guys using a manual system.

Another thing to consider is that every cat that has been flown 100% so far has been slower than its hull born sisters-the most recent being the C Class "Rocker". Yet, it has been proven over and over that cats with "foil assist" that only partially lift the boat are faster than the non foil assist boats. Somebody earlier said : "lets see the video" that would probably tell a lot....

Still, its so cool to see this boat flying-just fantastic!

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............. look at Hydroptere for a king example. Also the comments about the great length of the lee daggger/foil and that only half the depth is being used, well, the platform is flying very high anyway ... and the dagger/L should be lifted further, imo. But what do I know, ................................... Foiling sailors pointed out this save your ass design setup months/years ago.

 

may I suggest, Coxcreek.... you know more than most lurking these forums and a shit load more than just about everyone who posts comments.

 

So, what's in the wing bubble?

 

The bubble could be just another version of a time honored AC tradition of a deception device. For those of you that have been in the game awhile you may recall Koch's " spy boat " which was supposed to be able to read all the telemetry info from competing boats as they practiced in SD. As it tuned out the antennas and wild looking radar type items on the roof of the boat were sourced from a local scrap yard. The boys on Koch's team had daily laughs over the reports of their spying and just what info they were stealing from everyone else. The nd result was a lot of time and energy devoted to what turned out to be a complete waste of time. This gyroscope talk could turn out to be the biggest joke of the year , so far that is . More to come for sure .

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On whether this transfers to the 72'a... THEORETICALLY, wouldn't a 45' full foiler run faster than a 72' immerssed hull? Then all you need to do is add some immersed prods to the bow to measure in at 72' and if it is faster....

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Because there is no wand, Doug is a disbeliever, it can't happen, Photoshop trickiness, therefore it is all phony and doesn't exist in real world. He has wiped his hands of this fantasy, not saying he won't be posting though. Plenty of foilers fly without actuating flaps and wands. look at Hydroptere for a king example. Also the comments about the great length of the lee daggger/foil and that only half the depth is being used, well, the platform is flying very high anyway ... and the dagger/L should be lifted further, imo. But what do I know, maybe the crew experiencing the reality feel the foiling at this height is the best balance and equilibrium. Also, in lighter airs, they would want the full depth because ... blah, blah, you all know the reasons. Likening this configuration with Off yer rocker is not correct; OYR had four deep foils dragging all the time, hence its lack of speed; this AC45 is sailing in the fresh wind, with only two foils working - okay the windward T rudder will be down some of the time but mostly wetted surface area there is low.

This is all good ... and those T rudders will stop the hyper powerful AC45's from going arse over head so frequently - that is, if this setup is legalised. Maybe the rulemakers will see the light and change. Foiling sailors pointed out this save your ass design setup months/years ago.

======================

I wondered about it being photoshopped but I no longer think thats the case after seeing the series of photos on Sail-World. But one things for sure: these are fully submerged foils-not surface piercing foils(that automatically adjust their altitude)-they MUST have some form of altitude control by all that is holy. If you took a Rave or an Osprey and ripped off the wands I can gurantee you that the boat wouldn't fly for long. However, the Rave was flown by two different guys using a manual system.

Another thing to consider is that every cat that has been flown 100% so far has been slower than its hull born sisters-the most recent being the C Class "Rocker". Yet, it has been proven over and over that cats with "foil assist" that only partially lift the boat are faster than the non foil assist boats. Somebody earlier said : "lets see the video" that would probably tell a lot....

Still, its so cool to see this boat flying-just fantastic!

 

Keep in mind Doug that this is a very different beast then Rocker was. She's sailing in more breeze, has way more power available to get flying and she's lifting her weather foils. We all know Rocker had too much junk in the water and that was driven by a low target take off speed in and around 10 knots. If we doubled that and sailed in a ton of breeze, it would have been a very different outcome, especially if we had pulled the weather foils up.

 

And sure they must have some pitch control, nobody says it has to be in the water however. I can tell you that we can make a big difference in the pitch of the boat just by managing the twist in the wing, from bow down to a wheelie. Moving ones weight around helps too and the 45 is still small enough that crew movement has a meaningful effect. You can still design for static pitch stability. You might also consider the skill set of the crew involved, arguably they have about the best "feel" you could hope for in a crew to keep her up one wheel.

 

I don't think we can write the "bible" just yet to determine what exactly is holy and what is not.

 

Controlled lift fraction will be a huge differentiator amongst the competitors in the cup. How big are your balls? How high are you prepared to fly? How little control can you get away with and still land it if you really have to?

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As for pitch control, it can be best done using rake on the rudder, only small angular changes are required.

 

And would this get past the adjustable foil rule? if so, helm can handle that with a "twist grip" on the tiller extension ala the Bieker I-14 gantry foils.

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I would think the ideal attitude would be with the windward hull just touching the water and the leeward hull well clear.

 

Like this? http://dougculnane.b...-class-cat.html

 

It looks so wrong but I guess that's just what we are used to.

 

Yes, though that might be one of the "let's have some fun" photos. In most of the others I've seen, Rocker was sailed flat. The crew would need to adjust the wand from tack to tack to achieve leeward heal, much better to lift them but that makes a wand system more complex (perhaps hydraulic connections can be used with flexible tubes).

 

The driver is Rohan Veal, multiple foiling Moth World Champion, so no mug at the helm. But it was 5 years ago, it would be interesting to see what Nathan Otteridge would get out of it, and what changes would be made given what's been learned from Moths in the meantime. e.g. end plates on the rudder foils are slow, it's more efficient to make the foil longer, and the main foil design seems to be where John Illet was at about that time: The evolution of moth main hydrofoils. Even this article is 2 years old and doesn't include changes made recently.

 

I have no doubt that Oracle have the time and money to develop a more efficient system. Maybe the Koreans bought Otteridge as a defensive move to stop him working with OR!

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I can tell you that we can make a big difference in the pitch of the boat just by managing the twist in the wing, from bow down to a wheelie.

 

That's interesting. I guess more twist = bow down?

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I would think the ideal attitude would be with the windward hull just touching the water and the leeward hull well clear.

 

Like this? http://dougculnane.b...-class-cat.html

 

It looks so wrong but I guess that's just what we are used to.

 

Yes, though that might be one of the "let's have some fun" photos. In most of the others I've seen, Rocker was sailed flat. The crew would need to adjust the wand from tack to tack to achieve leeward heal, much better to lift them but that makes a wand system more complex (perhaps hydraulic connections can be used with flexible tubes).

 

The driver is Rohan Veal, multiple foiling Moth World Champion, so no mug at the helm. But it was 5 years ago, it would be interesting to see what Nathan Otteridge would get out of it, and what changes would be made given what's been learned from Moths in the meantime. e.g. end plates on the rudder foils are slow, it's more efficient to make the foil longer, and the main foil design seems to be where John Illet was at about that time: The evolution of moth main hydrofoils. Even this article is 2 years old and doesn't include changes made recently.

 

I have no doubt that Oracle have the time and money to develop a more efficient system. Maybe the Koreans bought Otteridge as a defensive move to stop him working with OR!

 

No we (Rocker) didn't have to adjust the foils by hand to do anything, they were fully auto like a moth, one per side, simple as that. To make it heel to windward, we could do it without changing anything other than wing trim, but it worked better if we disengaged the weather foil so you didn't have to fight it to get the windward hull down. The rudder foils were adjustable with a twist grip tiller extension. That was a PITA system but by no means was it the downfall of the concept.

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As for pitch control, it can be best done using rake on the rudder, only small angular changes are required.

 

And would this get past the adjustable foil rule? if so, helm can handle that with a "twist grip" on the tiller extension ala the Bieker I-14 gantry foils.

 

8.3 Rudders shall rotate only, and that rotation shall be about a single axis which is within 10

degrees of vertical. This rule does not prohibit the use of self-aligning rudder bearings.

 

8.6 Rudders shall not have components such as trim tabs or moveable winglets, that can be

adjusted while racing. However, a movable or retractable device whose sole purpose is the

removal of weed or debris is permitted.

 

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Interesting to see that my man crush Laird Hamilton was onboard:

 

30uv4aw.jpg

 

Hamilton is not new to this foiling stuff either:

 

2m2bz2x.jpg3128fhc.jpg

 

WetHog :ph34r:

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Controlled lift fraction will be a huge differentiator amongst the competitors in the cup. How big are your balls? How high are you prepared to fly? How little control can you get away with and still land it if you really have to?

=====================

I think you may have nailed it here!

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from a control perspective, my thought is that the rudders are the biggest concern. I estimate that there is only half the rudder (<1/4 area) left in the water in the shot which leaves it vulnerable to leaving the water entirely.

 

Pitch or yaw control with the tiny horiz stabilizer/rudder areas isnt going to be very effective at that point.

 

If you loose your rudder, what is the possible aoa range of the main foil assuming it is fixed relative to the hull. If you go past the zero lift aoa it's going to start pulling the boat in, catastrophic turtling inevitable.

 

Either that, or the balance needs to be wayyyy out. Which cannot be optimal, and is not reflected by more balanced stabilizer areas between the dagger and rudder.

 

I think this might be dis-information.

As for pitch control, it can be best done using rake on the rudder, only small angular changes are required.

 

And would this get past the adjustable foil rule? if so, helm can handle that with a "twist grip" on the tiller extension ala the Bieker I-14 gantry foils.

 

8.3 Rudders shall rotate only, and that rotation shall be about a single axis which is within 10

degrees of vertical. This rule does not prohibit the use of self-aligning rudder bearings.

 

8.6 Rudders shall not have components such as trim tabs or moveable winglets, that can be

adjusted while racing. However, a movable or retractable device whose sole purpose is the

removal of weed or debris is permitted.

 

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anybody found a pic with a view of the tiller / tiller extension? That would answer a bunch of questions being raised here..

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anybody found a pic with a view of the tiller / tiller extension? That would answer a bunch of questions being raised here..

 

See reply above where the rules limit rudder design.

 

 

 

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anybody found a pic with a view of the tiller / tiller extension? That would answer a bunch of questions being raised here..

There is this one, go to here then "Click here to view large photo." Still, hard to tell what's going on back there.

 

Alt_GG12SFOJUN37581.jpg

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I think they are just having fun with the rest of us. With only one lifting foil in the water, stability has got to be a momentary thing. They've been testing L-boards, and these pictures were taken on a particularly windy day during an exciting and photogenic moment. It's very cool to think about, though.

 

(In the picture above, I don't see a t-foil on the port rudder. Am I missing it somehow?) NEVER MIND. Looking at the larger version, I see it.

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Interesting to see that my man crush Laird Hamilton was onboard:

 

30uv4aw.jpg

 

Hamilton is not new to this foiling stuff either:

 

2m2bz2x.jpg3128fhc.jpg

 

WetHog :ph34r:

 

Kind of amazing he was in town and so stealthy...and no eye witnesses in the central bay of turboed AC45?

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Interesting to see that my man crush Laird Hamilton was onboard:

 

30uv4aw.jpg

 

Hamilton is not new to this foiling stuff either:

 

2m2bz2x.jpg3128fhc.jpg

 

WetHog :ph34r:

 

Kind of amazing he was in town and so stealthy...and no eye witnesses in the central bay of turboed AC45?

 

Looking at the video Stinger put up of Hamilton's visit in the OR thread it would appear he was not on the foiled cat. The foiled cat is #5 and Hamilton was on #4 with JS. Not sure why sailworld put Hamilton's photo in there with the foiled cat pictures, but that led me to believe Hamilton was on that boat. Oh well.

 

WetHog :ph34r:

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^ Correct. But 4 was sailing with the gizmo wing iirc (certainly has at other times) which ~could~ suggest the gizmo is unrelated / not unique to the foiling 5.

 

I hope somebody asked Kramers and Co, today in Newport; that damn thing is driving me nuts!

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Is it possible this wing has a 'twistable' leading edge, being controlled by a mechanism inside of that gizmo/bulb?

 

At the base of the mast just behind the CORE label (other masts don't have that label btw) there is visible what could be a vertical 'element' separation.

 

Alt_GG12SFOJUN33121.jpg

 

You can make it out in this one too

 

Alt_GG12SFOJUN32871.jpg

 

It may explain why the gizmo seems to almost wrap around the the wing, perhaps with control arms inside of it?

 

Alt_GG12SFOJUN35821.jpg

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The final inverted T of the rudder can be viewed very well in the original photo of Voiles et Voilers

 

335b904fd09db211a9f6dc933a4e48d9.jpg

 

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what is the L word anyway? My first thought was Launched. Though maybe two hulls/lesbian reference - male dream/fantasy. Love to get launched from a pair of lovely lubricated lesbians.

 

Maybe. Lookout! Liftoff!

 

Maybe LMAO

;)

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Do we have a pictures showing us the twist at different moments ?

I can only find the four shots at SailWorld, one of which is also the photo at V&V. Tried to find Grenier's larger collection if he has one somewhere, struck out so far.

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CupInfo

‏@CupInfo

 

Oracle Team USA conference call: Dirk Kramers, Design team, confirmed exploring / testing lifting foils #AmericasCup

 

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1. Impressive composite work in the 90d.

2. Ventilation with shallow surface piercers in chop?

3. Lateral resistance changes?

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At the base of the mast just behind the CORE label (other masts don't have that label btw) there is visible what could be a vertical 'element' separation.

May be just shadow lines, my imagined 'separation' is not visible in these recent, still-interesting shots - seen at here

 

ot2eps.jpg

 

xkw50j.jpg

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The pod(s) could be there simply to reduce windage from the trimming lines.

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It's the rig's power that provides the balance and stability when foilborne. I think you have to look at the system as a whole. When a Moth crashes, it's usually a result of the rig being out of balance not a foil angle-of-attack problem.

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I wonder how they are controlling the pitch angle on the board, as it doesn't look like they are adjusting it on this one - just the standard AC 45 setup. Fascinating - don't see the t foil rudder pitch control either, but it is a far away shot. Nice scoop.

 

The AC72 class rule prohibits adjustable foil surfaces while sailing, except for a weed knife.

 

When I was testing Greg Ketterman's bi plane foiler in the 1990s the foils were no "adjustable" but rather auto correcting. By far the best days of sailing ever. Sailing on foil is magical and the G forces in the gybe are amazing. It is super quiet and surreal acceleration. I can't imagine what the momentary loads look like on a 45 let alone a 72 but I'll tune in to watch it that's for sure...

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Interesting that the daggerboards on the foiler are forward of the front beam while on other boats they were behind the beam....

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I think they are just having fun with the rest of us.

 

Video or it didn't happen <_<

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Maybe the rear beam has been put more aft and the wing modded so that the main spar support point is more aft. Therefore you need more purchase to adjust, aka the pods on the sides. The mods were done to get the weight balance more optimal to the foils without changing the sailiplane (wingplane) balance on the daggerboards. I think its actually a semifoiler cabaple of full foiling with the lift being adjusted from the rudder segments. This would mean full flight is not the fastest foiling position, but doable.

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That looks like it's just a moment of glory. Design the lifting foil so it only lifts the whole boat when you are absolutely screaming, like in the photo on a broad reach. Perhaps they can adjust angle of incidence somehow but not actively I'd guess.

 

Though the rule was intended to prohibit active foil controls, AFAIK it only prohibits flaps and long daggerboard trunks. There are ways around that limitation but they are pretty clever. I would be surprised if no one is trying them out, but I don't see it happening in this series of photos.

 

IIRC the tradeoff occurs at 18 knots. Above that speed, you're better off out of the water on a 72' hull. Since these boats will go that fast and more upwind, they would theoretically be better off on foils all the way around the course. But this system seems like it is only designed to assist, and in the photo they are just showing off a bit.

 

My $.02

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That looks like it's just a moment of glory. Design the lifting foil so it only lifts the whole boat when you are absolutely screaming, like in the photo on a broad reach. Perhaps they can adjust angle of incidence somehow but not actively I'd guess.

 

Though the rule was intended to prohibit active foil controls, AFAIK it only prohibits flaps and long daggerboard trunks. There are ways around that limitation but they are pretty clever. I would be surprised if no one is trying them out, but I don't see it happening in this series of photos.

 

IIRC the tradeoff occurs at 18 knots. Above that speed, you're better off out of the water on a 72' hull. Since these boats will go that fast and more upwind, they would theoretically be better off on foils all the way around the course. But this system seems like it is only designed to assist, and in the photo they are just showing off a bit.

 

My $.02

So an articulating rudder gantry ala the I14s would work here... ok.

 

And if a 45'er converted to a 72' via prods is at least as fast in 18kn+ Seems to me that's the way you go.

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These boats normally top out at about 27kts, correct? I wonder how fast they were going in the picture?

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Good question. In the link I posted above, to the Opti kid's photos, he says that on the day he was on board the boat hit 34 knots. It's the highest AC45 speed figure that I've seen; so even if it wasn't fully lifted the day he was out, they've got that same boat really moving. Maybe too fast?

 

edit: he wrote "When I got back on the chase boat the AC45 got up to 34 knots, the max speed for the day."

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The lee daggerboard is only half extended, which means the horizontal portion is at or very near the surface - not a steady state condition, unless it's designed to work as a surface piercing foil

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Real AC porn!

 

I was waiting for this for a while!!!!

 

But: once they are out, the lateral resistance force needed and provided by the standard daggerboard haye surely droped, It could be a good thing for vmg downwind, but surely not upwind! If my premises are correct, why did they not place the horizontal part of the L higner on the board to keep more vertical surface in the water and therefore more lateral resistance? And the same thinking can be made on the rudder... once they are up, they keep just a few square centimeters of the rudder effective, which could be very dangerous for controling the boat at those speed...

 

Foil a little bit upper on the board, like inverted f, in the spirit of this incredible new boat

 

more pics and infos: P28 foiler - le chantier

post-38390-093100900 1340660397_thumb.jpg

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So what happens in the "big boys' bear-away" if you're still foiling? Leeward bow drops as the platform powers up, and the rudder pops out. The result would not be a good look, I think.

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