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48 minutes ago, JALhazmat said:

What are the rules governing two foils down in the start box? Could be a fun way of staying air-born and stable in event of any pre start shenanigans? 

I was thinking something similar, "is this pre-start practise" 

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Anyone have a handle on the 2 foils down rule?? Yes it is draggy but could there be an ability to point very high to the wind in that mode??

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It may change.

The AC75 Class Yacht is not designed to resist righting-moment created by hydrodynamic downforce on
the windward foil. Following sailing trials and experience gained by Competitors, the Rules Committee,
with the agreement of COR/D and the Regatta Director, and in consultation with Competitors, may amend
this Rule to place restrictions on the use of the FCS
including, but not limited to:
(a) a restriction of:
(i) the amount of negative cant moment (moment in the sense of reducing cant angle) that may
be sustained by the FCS; and
(ii) the cant angle that may be set for the windward foil;
(b) which may be applied at all times, or only in certain conditions, such as:
(i) when in a normal sailing mode, and not through a manoeuvre;
(ii) when within certain yacht speed or wind speed ranges; and
(iii) during certain stages of a race.
Such restrictions may be developed through sailing periods, but shall be frozen according to Rule 34.

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^ Thanks for that re-post. Maybe LR is testing the proposition and will favor a Rule change?

Similar subject: I wonder if teams can set the angle of attack on the foil wings relative to the arm or if the connection is completely fixed? Not while underway like with dynamic flap control, but easily pre-set before racing? 

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The screen grabs from a recent LR vid certainly shows where the wing  of the foil joins onto the bulb where rotation/angle could be set 

this was independent of the flap on the Trailing edge.

 

it could of course just be how it’s constructed in a modular form and was a wire frame drawing but you never know? 

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16 hours ago, uflux said:

Very interesting!!!

Foiling and tacking upwind with both foils down...

Ummm, what are we looking at?  Of course they put both foils down for maneuvers, otherwise they....fall over.

It's fairly windy, so it looks like they're putting them down earlier.  It's also Luna Rossa, so they're probably worried that shit's going to break, so they're taking it easy.

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1 hour ago, JALhazmat said:

The screen grabs from a recent LR vid certainly shows where the wing  of the foil joins onto the bulb where rotation/angle could be set 

this was independent of the flap on the Trailing edge.

 

it could of course just be how it’s constructed in a modular form and was a wire frame drawing but you never know? 

This?

Screenshot_20200609-193536.png

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One interesting detail is how the winglet chord is less than that immediately adjacent, or maybe the flap perennially sticks out somewhat. 

Regarding the above, an angle of the wing relative to the bulb would not be a very smooth joint, no?

Screenshot_20200616-180940.png

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1 hour ago, Ex-yachtie said:

Ummm, what are we looking at?  Of course they put both foils down for maneuvers, otherwise they....fall over.

It's fairly windy, so it looks like they're putting them down earlier.  It's also Luna Rossa, so they're probably worried that shit's going to break, so they're taking it easy.

It is after the mark rounding and sailing for a extended period upwind with both foils down that I am interested in

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35 minutes ago, buckdouger said:

One interesting detail is how the winglet chord is less than that immediately adjacent, or maybe the flap perennially sticks out somewhat. 

Regarding the above, an angle of the wing relative to the bulb would not be a very smooth joint, no?

Screenshot_20200616-180940.png

Going by that picture of the tell tales smoothness isn’t what they are going for? 
 

but the join can be faired in IF they were going for adjustability of angle, certainly in testing it might be helpful? 

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6 minutes ago, uflux said:

It is after the mark rounding and sailing for a extended period upwind with both foils down that I am interested in

Nah. The foil goes up almost immediately. You can see the tip of the wing through the window. 
 

I do get your point though. They drop both foils coming into a leeward mark. My reading of it is that they were too high, needed to drive low and risked dropping the hull in the water (which kinda feels catastrophic - rig falls to windward and gets blown around a buried bow). 

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18 minutes ago, barfy said:

No one is gonna put anything on a computer in front of a camera that means squat. Eyecandy.

Disagree, they clearly put time into that concept, whether it was superseded or not.
 

It’s a cool shot, could have instead been been a bizarre little monkey named Herbie chomping on bananas instead. 

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4 hours ago, Ex-yachtie said:

Nah. The foil goes up almost immediately. You can see the tip of the wing through the window. 

Yep, it's also not a continuous shot, there's a cut at 1:11. There's also a splash from dropping the starboard foil at about 1:38, so it it must have been raised.

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5 hours ago, buckdouger said:

One interesting detail is how the winglet chord is less than that immediately adjacent, or maybe the flap perennially sticks out somewhat. 

Regarding the above, an angle of the wing relative to the bulb would not be a very smooth joint, no?

Screenshot_20200616-180940.png

Replaceable wing tips. Someone fucked up and left the correct size at home so they went with whatever was in the kit bag…

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11 minutes ago, RobG said:

Replaceable wing tips. Someone fucked up and left the correct size at home so they went with whatever was in the kit bag…

Shrug, it’s just the new norm in La Dolce Vitae, all good! 

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2 hours ago, RobG said:

Replaceable wing tips. Someone fucked up and left the correct size at home so they went with whatever was in the kit bag…

Haha.. possibly, but the CAD image shows the same discontinuity. 

As for the eye candy comment, an experienced eye can see they are relevantly similar, and in fact, why hide the CAD of something you have sailed? With the split lines mostly hidden, you can do no more with that screenshot than a photo really. 

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On 6/19/2020 at 1:54 PM, buckdouger said:

Haha.. possibly, but the CAD image shows the same discontinuity. 

As for the eye candy comment, an experienced eye can see they are relevantly similar, and in fact, why hide the CAD of something you have sailed? With the split lines mostly hidden, you can do no more with that screenshot than a photo really. 

I believe never believe anything that teams publish or say in interviews. Actually, think about what they are obscuring. 

Book of war

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On 6/19/2020 at 3:47 PM, Xlot said:

With thanks to the (AM?) spy who provided he video

But this is interesting..either spity got scared..Or soaking it low as the Italian guys say...

And going high mode for tacks we have talked about, especially light air as etnz did in bda, whether you need to do it in the fresh..well early days.

As the Italian guys say, soon we will get indications regards strategies for manoeuvres when 3boats start training in NZ

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3 hours ago, Liquid said:

The most exciting thing to happen recently is one team left both foils down after an auto tack...

The longer this foiling thing goes on the more I miss watching the TP52s!

Stand by for the S&S news! 

What's the over/under on that coming before LR breaks something?

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On 6/18/2020 at 6:15 AM, barfy said:

Looks slow like molasses. Maybe a method to put the brakes on for a time on distance, but still stay up. They'd certainly have the competition sail right by them if they try out that Shit on the track.

Here are some speed calculations when both foils are in the water:

1:17 mark   27.4 knots

1:26 mark   28.7 knots

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1 hour ago, The_Alchemist said:

Here are some speed calculations when both foils are in the water:

1:17 mark   27.4 knots

1:26 mark   28.7 knots

Nice.

Can you compare to speeds Before both arms went down at the same angle?

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3 hours ago, The_Alchemist said:

Here are some speed calculations when both foils are in the water:

1:17 mark   27.4 knots

1:26 mark   28.7 knots

Straight line speed is not as important as VMG in that mode, I would think.

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On 6/19/2020 at 9:51 AM, chesirecat said:

And again  via their twitter feed.

Contrary to the misleading position expressed this evening on

about delays to the AC, the Defenders position firmly remains unchanged: “to clarify speculation of movement of

regatta dates, the Defender confirms there is no change in the event schedule.”

https://twitter.com/EmiratesTeamNZ

Hmm ... not the first time the Defender makes unilateral statements, when in an ideal world they should be joint with the CoR - whose silence would point out that, naturally, a one month delay would be welcome

Incidentally, are authorities concerned about handling an immigration influx for the Cup simultaneously with Kiwis coming home for Xmas?

 

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4 hours ago, Xlot said:

 

Hmm ... not the first time the Defender makes unilateral statements, when in an ideal world they should be joint with the CoR - whose silence would point out that, naturally, a one month delay would be welcome

Incidentally, are authorities concerned about handling an immigration influx for the Cup simultaneously with Kiwis coming home for Xmas?

 

Any kiwis that would come back are already coming home. Hence that shortage of quarantine hotel rooms.

we are not going to get an influx for the cup because the government will still have very strict quarantine measures in place. But hey thats on America’s cluster f@ck. Not us :rolleyes:

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1 hour ago, uflux said:

Any kiwis that would come back are already coming home. Hence that shortage of quarantine hotel rooms.

we are not going to get an influx for the cup because the government will still have very strict quarantine measures in place. But hey thats on America’s cluster f@ck. Not us :rolleyes:

OK. But then why are authorities in favor of delaying/compressing Cup events?

 

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On 6/19/2020 at 2:52 AM, Tornado-Cat said:
 
 
On 6/19/2020 at 2:52 AM, Tornado-Cat said:

It may change.

The AC75 Class Yacht is not designed to resist righting-moment created by hydrodynamic downforce on
the windward foil. Following sailing trials and experience gained by Competitors, the Rules Committee,
with the agreement of COR/D and the Regatta Director, and in consultation with Competitors, may amend
this Rule to place restrictions on the use of the FCS
including, but not limited to:
(a) a restriction of:
(i) the amount of negative cant moment (moment in the sense of reducing cant angle) that may
be sustained by the FCS; and
(ii) the cant angle that may be set for the windward foil;
(b) which may be applied at all times, or only in certain conditions, such as:
(i) when in a normal sailing mode, and not through a manoeuvre;
(ii) when within certain yacht speed or wind speed ranges; and
(iii) during certain stages of a race.
Such restrictions may be developed through sailing periods, but shall be frozen according to Rule 34.

think you have nailed it here.

rounding the bottom gate with a boat infront/behind you. you want to put doubt in the other teams mindset ... are they tacking? do we need to cover etc etc

its the equivariant of the old school boats doing a fake tack

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On 6/19/2020 at 6:25 AM, buckdouger said:

One interesting detail is how the winglet chord is less than that immediately adjacent, or maybe the flap perennially sticks out somewhat. 

Regarding the above, an angle of the wing relative to the bulb would not be a very smooth joint, no?

Screenshot_20200616-180940.png

image.thumb.png.b58a21bbfc0b7555510aed804ca46628.png

I'm not suggesting that the LR boat has an adjustable length but the intersection stepped joint is similar

back in my uni days a couple of friends were looking at the aerodynamics on the above joint for wind turbines (adjustable lengths depending on the amount of wind)

as we all know on standard wingtips there is an amount of air that passes around the tip from the high pressure to low-pressure side (hence why people invented winglets) you get some weird bleeding and corkscrewing of air around the stepped joint shown above, this is probably why LR has put the fencing in that area

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1 hour ago, Xlot said:

OK. But then why are authorities in favor of delaying/compressing Cup events?

 

I don’t think they really are. I am not convinced that was a real story. Especially given the way ETNZ made the statement. They will have been speaking to the relevant parties

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2 hours ago, Tornado-Cat said:

@ Lickingdip, yes I agree with you, I think it could also be used to go deeper downwind if it can prevent from one gybe, or if they could miss one door.

It might also be used for more stability in strong conditions downwind.

 

I'm not disagreeing with you but curious as to how you think the mechanics of 2 foils in the water allow you to point further downwind ... I'm sure we would have seen this on an AC50 if it was helpful

same again for stability comment ... surely more weight away from the pivot point (as wide as possible) means greater control ... unless you are thinking they are aiming for downforce with the flaps (similar to the windward rudder on the AC50)

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Just now, Lickindip said:

I'm not disagreeing with you but curious as to how you think the mechanics of 2 foils in the water allow you to point further downwind.

 

Pointing more = less apparent wind = less speed = less foil lift = need for more foil surface immerged.

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Watching again this video:

1) They seem to have less foil arm cant

2) They fly higher with same amount of foil arm immerged

3) The foil is more centered = less RM = allows to fly in ligther wind and deeper.

So, what is about the "endplating" or is it pure bullshit ?

 

 

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1 minute ago, Tornado-Cat said:

Pointing more = less apparent wind = less speed = less foil lift = need for more foil surface immerged.

so to gain maybe the 20% more lift they need you are suggesting doubling the drag in the water ... seems that could lead to slowing rapidly as they have less apparent wind and would drop into displacement mode

from what we have seen these boats can foil in 6knts of breeze, ill take a guess and say the take-off speed is 12knts. lets round that to 15knts to be safe (anything lower they drop into displacement) ...if they had a need to point lower they can pretty much reduce their speed to 15knts before needing extra lift (2nd foil in the water)

I get the feeling we would have seen this technique on the AC50 or the F50 by now if it was viable

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8 hours ago, Lickindip said:

so to gain maybe the 20% more lift they need you are suggesting doubling the drag in the water ... seems that could lead to slowing rapidly as they have less apparent wind and would drop into displacement mode

from what we have seen these boats can foil in 6knts of breeze, ill take a guess and say the take-off speed is 12knts. lets round that to 15knts to be safe (anything lower they drop into displacement) ...if they had a need to point lower they can pretty much reduce their speed to 15knts before needing extra lift (2nd foil in the water)

I get the feeling we would have seen this technique on the AC50 or the F50 by now if it was viable

Your argument about the AC50 or F50 is the best. However the AC75 is a heavier boat and we have seen these two foils in the water in strong conditions, they might be able to go very deep then. It may not mean better vmg but just to avoid a gybe in some conditions.

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9 hours ago, Lickindip said:

so to gain maybe the 20% more lift they need you are suggesting doubling the drag in the water ... seems that could lead to slowing rapidly as they have less apparent wind and would drop into displacement mode

from what we have seen these boats can foil in 6knts of breeze, ill take a guess and say the take-off speed is 12knts. lets round that to 15knts to be safe (anything lower they drop into displacement) ...if they had a need to point lower they can pretty much reduce their speed to 15knts before needing extra lift (2nd foil in the water)

I get the feeling we would have seen this technique on the AC50 or the F50 by now if it was viable

Keep in mind that with double the surface area you don't necessarily double the drag as you would not load either foil as much.

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6 hours ago, Tornado-Cat said:

Your argument about the AC50 or F50 is the best. However the AC75 is a heavier boat and we have seen these two foils in the water in strong conditions, they might be able to go very deep then. It may not mean better vmg but just to avoid a gybe in some conditions.

would be interesting to do the basic calcs for which boat foil is more loaded per m^2 of foil size

AC 50 = 2,332–2,432 kg

AC75 = 7,600 kg (16,800 lb) loaded

at a guess would you say the AC75 foil area is 3x that of the AC50?

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49 minutes ago, Lickindip said:

would be interesting to do the basic calcs for which boat foil is more loaded per m^2 of foil size

AC 50 = 2,332–2,432 kg

AC75 = 7,600 kg (16,800 lb) loaded

at a guess would you say the AC75 foil area is 3x that of the AC50?

I don't know, but don't forget that the F50 has 2 rudder foils.

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7 minutes ago, Tornado-Cat said:

I don't know, but don't forget that the F50 has 2 rudder foils.

not disagreeing with you there.

there will be a ratio between main foil size and rudder size. I was referring to general foil size required to lift boats out of the water

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10 hours ago, david r said:

The superfoilers would occasionally sail with both main foils in the water to stabilize their foil-borne racing.

Not a good comparison to cite IMHO. They were a sqirrely beast even when "tamed" and that was after many months of being pretty much unsailable.

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23 hours ago, Lickindip said:

so to gain maybe the 20% more lift they need you are suggesting doubling the drag in the water ... seems that could lead to slowing rapidly as they have less apparent wind and would drop into displacement mode

from what we have seen these boats can foil in 6knts of breeze, ill take a guess and say the take-off speed is 12knts. lets round that to 15knts to be safe (anything lower they drop into displacement) ...if they had a need to point lower they can pretty much reduce their speed to 15knts before needing extra lift (2nd foil in the water)

I get the feeling we would have seen this technique on the AC50 or the F50 by now if it was viable

You make valid points here, and I think that different conditions (light air to heavy breeze) and direction will cause different modes to be in play - and NOT comparable.

So in Heavy Air, Start box manouevring, they may want to sail both foils down to use the additional lift and drag to go somwhere or simply slow up their approach. Useful tricks to have your disposal in a highly dynamic setting.

But in super light air, where foiling is marginal, there seems, as you pointed out no valid reason why you would want to increase drag in any capacity whatsoever. In these marginal conditions where staying in flight mode completely kills the alternate displacement mode, then flying higher with the Foil rotatated down to max flying extent and thereby shortening the RM lever allows the lift to be closer to the COG and flying higher (in what is generally smooth flat conditions) allows the team to fly as high as practically possible. This gives "sink" time to allow the boat to manage short lulls in pressure with less risk of touchdown.

In more moderate conditions - say 9 to 12 knots - the boat speed is almost always above that flight threshold and the rig is already at max horsepower. The water is still smooth and mainly flat. This would be where we witness - lower flight height and bow down (upwind) as the immersed foil is set more laterally to increase the RM lever to max. The Lower flight height and bow down on smooth water maybe where they chase the theoretical gains of Reflection plane attitude - not endplating in the throwaway terms that are used here, but being bown down also allows, the forestay to be more vertical and the whole rig to give more optimal aero properties. There is also less rudder immersion of the vertical element thereby minimising drag to the lowest possible state.

By the time the breeze is top end again, the gains from these settings are offset by the risk of touchdown or stacking it. So you will not witness the same hunt for refinement or ultimate performance in favour of a little more safety/security whilst still making the the whole race a dry lapping affair. 

But to say that because some modes are only used in certain situations does not make them universally applied or continuously utilised, nor does it make them any less valid for when they are used. It is merely optimisiing for the direction and conditions of the moment. 

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im still doubting the 2 foil in the water theory.

simple force diagram ... if each foil is supporting approx half the weight of the yacht you have no righting moment, any breeze would lift the windward foil out of the water, you wouldn't be creating enough lift off one foil at that speed so you would drop off that foil into displacement mode. and likely tip over ... take for example the etnz capsize

 

the AC50/F50 cats have the same principle of righting moment etc, the only difference is their hull is above each of the foils instead of centred

im more then happy to eat my words if proven wrong but we would have seen this style done already.

in the AC50's most mosts had to sink low on a downwind for some reason, they never dropped in both foils as you would have had to depower an already reduced rig and a compromised angle

 

image.png.c55aa77335d3e03c7e7c479ade639724.png

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On 6/20/2020 at 6:51 PM, phill_nz said:

i love the 0.4 - 0.7  claimed accuracy

maybe ~27 - ~ 29 might be more realistic

No intention to claim precision within 0.1 knots.  Just giving the results of the calculations to show relative speed, the second reading is definitely faster than the first.  Of course rounding may be more accurate, but it may not show the differences in speed.     I would estimate the actual speed to be within a couple knots of the calculations.  Errors could be present in the estimation of the boat length based upon angle of the boat, but as long as the course remains consistent (as in these two readings) the error is the same.  

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On 6/24/2020 at 2:24 PM, Lickindip said:

im still doubting the 2 foil in the water theory.

im more then happy to eat my words if proven wrong but we would have seen this style done already.

in the AC50's most mosts had to sink low on a downwind for some reason, they never dropped in both foils as you would have had to depower an already reduced rig and a compromised angle

Didn't the AU F50 have "eagle" mode occasionally when approaching the leeward mark?

Both foils down doesn't necessarily mean 50/50 weight distribution, particularly as the AC75s have much better control of lift than the AC72s and 50s. In the case of running very deep downwind, a reason to drop the windward foil is that there's too much RM and the boat is in danger of falling to windward. Dropping the windward foil can fix that.

Sure it's likely slow, but when you've run out of room to squeeze in two gybes, it might be useful. I think it's worth practicing, even if just as a boat handling exercise. It might also be useful in match racing at the bottom mark.

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About the bulbs on trailing edge underside on one of LR’s foils: they say probable purpose is housing flap actuators to achieve twist (between the flap’s center and tips)

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On 7/9/2020 at 12:49 AM, RobG said:

Didn't the AU F50 have "eagle" mode occasionally when approaching the leeward mark?

Both foils down doesn't necessarily mean 50/50 weight distribution, particularly as the AC75s have much better control of lift than the AC72s and 50s. In the case of running very deep downwind, a reason to drop the windward foil is that there's too much RM and the boat is in danger of falling to windward. Dropping the windward foil can fix that.

Sure it's likely slow, but when you've run out of room to squeeze in two gybes, it might be useful. I think it's worth practicing, even if just as a boat handling exercise. It might also be useful in match racing at the bottom mark.

any chance you can source the video for the 'eagle' cant say I've seen it

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Just watched the LR web series, and in Episode 4 I saw a frame where JS was hanging something in the hands, like a small computer, while in every other shot he's at the helm. Is it possible for you that they will switch roles ? For example, when JS is helming Bruni is the flight controller and vice versa. 

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1 hour ago, nav said:

I think you'll find that discussed back up there ^ somewhere....

One side each, at least until Max can make a choice?

Thank you @nav! Found the discussion, I think that they'll be both onboard for sure, maybe with the switching helm/flying control configuration, or maybe with one of them helming and the other at the foil control. I'm curious to see who else will be on the boat. Mongelli seems to be the natural choice as the navigator, I'm curious to see who will be the tactician. 

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31 minutes ago, Zaal said:

I'm curious to see who will be the tactician. 

My guess. There’s a recent audio interview with him above somewhere posted by me where he (I think) talked who-does-what in good detail.

 

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On 7/12/2020 at 8:21 PM, Stingray~ said:

At one point VV says ‘hopefully I will be on board, but possibly not.’

Anyway, it’s a super-fun and informative listen.

Thank you @Stingray~ I'm gonna watch it right now !!:) VV is a very good choice as tactician. Pierluigi de Felice could be the trimmer (but I remember someone else trimming the Little Moon with the joystick control, I don't remember who it was, maybe Andrea Tesei (in his Instagram page hedescribe himself as trimmer for Luna Rossa Challenge). We'll see ! 

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On 7/12/2020 at 8:21 PM, Stingray~ said:

At one point VV says ‘hopefully I will be on board, but possibly not.’

Anyway, it’s a super-fun and informative listen.

Personally, not a fan. Mind you, he’s a top TP52 tactician, but in the past he was quite vocal against multihulls and in favor of conventional, large crew > jobs program boats. So, his conversion on the way to Damascus is quite suspect, and possibly related to his finally getting into LR’s circle - don’t know if his experience would be relevant, too

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6 hours ago, Xlot said:

Personally, not a fan. Mind you, he’s a top TP52 tactician, but in the past he was quite vocal against multihulls and in favor of conventional, large crew > jobs program boats. So, his conversion on the way to Damascus is quite suspect, and possibly related to his finally getting into LR’s circle - don’t know if his experience would be relevant, too

I moreless agree. You wonder really how some very good but not exceptional ita sailors got to the 2021 LR team, since they were not definitely in the mix, in previous campaigns. We'll see how the team will progress.

I am also wondering if ruggi tita is now out of the team, since he is focusing heavily on the tokio nacra selection.

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1 hour ago, buckdouger said:

 

Whilst this is undeniably fast and good looking, they appear to be sailing across the face of the wind (slightly upwind) but certainly not close hauled. Is this just an art/promo shot? Because the new AC courses have no reaching legs - yet the chase boat suggests that they have been legging it like this for c.500m. 

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21 minutes ago, Boink said:

Whilst this is undeniably fast and good looking, they appear to be sailing across the face of the wind (slightly upwind) but certainly not close hauled. Is this just an art/promo shot? Because the new AC courses have no reaching legs - yet the chase boat suggests that they have been legging it like this for c.500m. 

Not sure I'm seeing what you are.

The RIB track looks to have made a pretty big turn, and if you think they're close reaching that means before they would have been going DDW or close to it.  Also the little wavelets look like the wind coming from bottom right of the photo. This looks upwind to me, and like they'd turned up from their downwind reaching angle a little while ago. 

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5 hours ago, JALhazmat said:

Anything will if it’s close enough to the surface and travelling fast enough 

It's interesting the convergence to the curved up tips...(DL). They seem to be purpose made for ventilation, I know it sounds mad, but maybe super cavitation? Seem to be a lot of shots of tipbubbles.

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I wonder if some people truly understand what cavitation does with foils let alone super cavitation.  Super cavitation reduces the efficiency not improves it.  They are all striving for laminar flow 100% of the time.

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3 minutes ago, trt131 said:

I wonder if some people truly understand what cavitation does with foils let alone super cavitation.  Super cavitation reduces the efficiency not improves it.  They are all striving for laminar flow 100% of the time.

I guess my impression is that the shape of the foil could be optimized for cavitation or optimized for flow, but not both? Not sure if there is some happy medium, but I am guessing they are striving for that. Seems inevitable that some of the foils will be cavitating some of the time.

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6 hours ago, barfy said:

It's interesting the convergence to the curved up tips...(DL). They seem to be purpose made for ventilation, I know it sounds mad, but maybe super cavitation? Seem to be a lot of shots of tipbubbles.

It’s a vortices as the flow detaches

bubbles would Indecate the flow breaking down.

supercavitation needs a completely specific  foil Shape to achieve, you cant just push a normal foil section until SC, As it just stalls and looses lift 

SC needs huge power to overcome the inefficient nature of the foil and then it does its thing 

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13 minutes ago, buckdouger said:

 

So did you notice the jump in the footage?

They had to edit out the Seagull that was flying past - a Glaucous Winged Gull - less the spies be able to deduce their speed........

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1 hour ago, Boink said:

So did you notice the jump in the footage?

They had to edit out the Seagull that was flying past - a Glaucous Winged Gull - less the spies be able to deduce their speed........

Were you high on drugs these last hours ?

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