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On 1/04/2018 at 2:19 AM, GBH said:

The biggest thing though is that instead of making this more about the people than the boats, then it's become more and more complex in terms of systems and they have the token monkeys just to provide a bit of power.  F1 has gone down that path and is losing it's sporting attraction and revenues as a result. 

And to think they could have just dialled back to a conventional ~60 foot cat...

 

15 hours ago, Stingray~ said:

Given the controllable foil wing flaps, would it be possible to set the yacht in still water and (gently) propel it forward by canting the foil arms underwater, like a bird flapping its wings in air?

4.2 The AC75 Class Yacht shall be propelled by sails only.

 

Regarding mainsails: I read it as allowing a relatively conventional double-luff, single surface windsurferish sail? I'm suspecting the relative simplicity, well known dynamics & weight advantage of that may come up trumps.

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Re Rule 5.5 : components counted only when installed on an AC75 yacht. I reiterate my opinion that foils, rudders and FCS will be initially tested on a (12 m + rudder gantry) non-surrogate towed platform, the case for that is only too obvious.

Furthermore, I'm now betting the mainsail will be tested in a fixed setup on land. Besides, with the foreseen boatspeeds the impact of different AOA at various height due to wind gradient is minimized

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10.12 Perimeter Line to be convex: there goes "my" wave-piercing bow :(

Figure 12.2 : quite a gash (with moveable fairing) for foil arm movement

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26.8 Not clear, I read this as saying flaps and rudder rake can be powered by the FCS batteries ??

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^ pretty clear.....systems may be powered by the FCS’s batteries

but be careful - you can only go to the well so many times! :D

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1 hour ago, nav said:

^ pretty clear.....systems may be powered by the FCS’s batteries

but be careful - you can only go to the well so many times! :D

"may" makes it optional..

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On 3/31/2018 at 9:43 AM, Terry Hollis said:

I think it would be safe to assume that the supplier will be required to stock spares for all the supplied items.

Ok, but the teams are only allowed 2 pairs.   Is there language stating what happens if they need a 3rd pair?

wetHog  :ph34r:

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1 hour ago, Indio said:

"may" makes it optional..

Yep...exactly. :huh:

He said 'can', the rule says 'may' - no problemo.......you can do whatever you want!

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40 minutes ago, WetHog said:

Ok, but the teams are only allowed 2 pairs.   Is there language stating what happens if they need a 3rd pair?

wetHog  :ph34r:

Didn't you say you were gonna relax about this?

Had the COR/D included the cost of spares for everything and simply dumped it on the Teams, you can guarandamntee that the regular whiners would have still be howling!

I already quoted the 'language' - chapter and verse @ post #246

Let it go, you'll get an ulcer.....

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On 29/3/2018 at 10:52 PM, nav said:

20.7 Energy supplied by the crew to move control surfaces must primarily be transmitted through the crew’s

hands

 

So, which way is it? Typical Rule double-speak? If it may be either manual or battery power, it should be a no-brainer. But then the only physical effort from the crew would be sheet winches, no?

 

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^ OMG.

When the crew is supplying energy - it must to be with hands, not feet etc. OK?

Could be through winch handles,  pedestals, hauling on a sheet or halyard even...

But for some functions, and you highlighted 2, foil wing flaps and rudder rake , they have been given the option to do it manually or - to use the  FCS batteries.

 

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On 31/3/2018 at 5:29 PM, nav said:

It was what you added that left a lot of guess work!

How many Ailerons, how many flaps... (but we've cleared that up now)

I take it that you are noting that there is no need for the (2 only allowed) 'flappy bits' attached to the foil wing to be the same?

So if a team believed there was an advantage to be had they could use different shapes and/or use the flaps independently and for different purposes.

Fair enough - looks like they could.

 

I think not - see 14.7

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^ Well spotted. They have to match (but can be used independently - or is that wrong too?)

Will you tell barfy?  He seems pretty invested?

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11 minutes ago, nav said:

^ Well spotted. They have to match (but can be used independently - or is that wrong too?)

No, same angle

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^ Both foil flaps of a foil shall have the same range of angular rotation.

 

.......... does not mean shall be at the same angle

 

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On 29/3/2018 at 5:50 PM, Tropical Madness said:

" There shall be eleven crew members, unless reduced by accident, who shall all be human beings. "

 

Maybe so, but nothing's said about the guest racer - that might then be a shit-throwing orangutang

 

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A skinny one maybe - there's a weight limit :D

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Is there a rule to forbid using spars to use the code zero as counter weight by locating it as far as possible overboard on windward when not in use? Is the advantage worth doing so and code zero available enough time? Or is the code zero considered as ballast when not in used, in which case located as described in 9.5?

The advantage might be negated by the aerodynamics effect already but could be interesting to have an extra 100kg located near the foil.

Quote

9.5 If one of the components listed below has a mass lower than that shown in Rule 9.1, ballast equal in mass
to the deficit shall be attached to the top of the hull surface at the following locations:
Component Ballast location
Jib On LCP, 11.0m forward of TRP
Code Zero On LCP, 14.0 m forward of TRP
Crew’s carried equipment On LCP, 5.0 m forward of TRP
Guest racer and their carried equipment On LCP, 1.0 m forward of TRP

 

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1 hour ago, nav said:

A skinny one maybe - there's a weight limit :D

Max. of 100kgs - or ballast added up to the max...I guess Kim Dotcom won't be a guest racer...

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Perhaps extra kilo$ are 'negotiable' ? ;)

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Just now, Tropical Madness said:

I see no reason why rowing machine type devices couldn’t be used. Power is tranmitted through the hands...

yeah, but it's not as efficient as grinders i don't think, you get to use your legs but it's not continuous like grinding, and the weight is moving around inside the boat

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^

Let's get the basics taken care of first

If the big item, canting the foils is taken care of, (plus rudder and flaps - if you choose), there is likely to be no 'arms race' (no pun intended) over power systems. Or?

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2 hours ago, inebriated said:

yeah, but it's not as efficient as grinders i don't think, you get to use your legs but it's not continuous like grinding, and the weight is moving around inside the boat

[IMG=http://fitwerx.com/wp-content/uploads/2012/06/chart2.jpg]

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If it's for pumping oil, rowing machines make sense. But 20.8 says you have to use hands and a rotary motion.

 

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Good spot on 20.8. In fact "in a rotary motion" means rowing machines are also out to pump oil.

20.8 One or more force input devices that are designed to allow more than one crew member to supply power
to a common mechanical drive train, a common pressure supply line or a common control function must
be grinding pedestals or winches that are operated by turning handles in a rotary motion with the hands.
This does not prohibit the use of other force input devices that occasionally allow more than one crew
member to provide simultaneous power (e.g. helm wheels), providing that is not their usual mode of
operation.

 

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19 hours ago, nav said:

Let's get the basics taken care of first

If the big item, canting the foils is taken care of, (plus rudder and flaps - if you choose), there is likely to be no 'arms race' (no pun intended) over power systems. Or?

 

Falling on deaf ears, apparently. Guess there's too much fun in beating a perfectly good dead horse :D

But indeed, headsail sheets are specified to use (manual powered) winches, what's left not covered: just mainsail winches? How will the 11 "human beings" keep busy?

 

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1 hour ago, Xlot said:

 

Falling on deaf ears, apparently. Guess there's too much fun in beating a perfectly good dead horse :D

But indeed, headsail sheets are specified to use (manual powered) winches, what's left not covered: just mainsail winches? How will the 11 "human beings" keep busy?

 

The wing control systems?

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On 01/04/2018 at 3:56 AM, Kiwing said:

Flap at the back of the wing? Is this possible or likely ?

Flap at the back.jpg

It's possible through a combination of mast rotation and control lines at each pair of full length battens.

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7 hours ago, dogwatch said:

Good spot on 20.8. In fact "in a rotary motion" means rowing machines are also out to pump oil.

20.8 One or more force input devices that are designed to allow more than one crew member to supply power
to a common mechanical drive train, a common pressure supply line or a common control function must
be grinding pedestals or winches that are operated by turning handles in a rotary motion with the hands.
This does not prohibit the use of other force input devices that occasionally allow more than one crew
member to provide simultaneous power (e.g. helm wheels), providing that is not their usual mode of
operation.

 

So one person rowing machines are ok after all (so much for incomplete quotes) :D

....not that they'll be needed

 

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I have a question or, two.

How thinly sliced will sailor be as one boat sails too close to another? And, how long will it take to cook the sliced meat to a medium rare state?

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^ after 20 pages of interesting discussion you come up with this. fuck off newbie, where's the tits FFS.

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On 4/3/2018 at 10:18 AM, nav said:

^ Well spotted. They have to match (but can be used independently - or is that wrong too?)

Will you tell barfy?  He seems pretty invested?

true that. I mean the symmetry around the foil arm being regulated. Haven't invested yet, won last Match at 9:1 in my first ever TAb with $500 wager.

What I am invested (finally time to have a better look) in is that  the foil wings can be 1.1m fore-aft, with over half of that flap surface. These are huge appendages compared to what teams ended up with last two cycles. (no pun intended).

Really some room for low speed lift. And i'm sure smart minds will find a way to adapt the high lift foil wing to high speed configuration.

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17 minutes ago, barfy said:

What I am invested (finally time to have a better look) in is that  the foil wings can be 1.1m fore-aft, with over half of that flap surface. These are huge appendages compared to what teams ended up with last two cycles. (no pun intended).

Reference please? All I saw is that foils are to be contained inside a 2 m wide belt (10-12 m forward of TRP)

 

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Figure 12.1: Foil geometry

looks like that to me, but I surely could be wrong.

and

14.8  At any cross-section and all foil flap rotation angles, when projected on to the foil wing projection plane, the length of a foil flap must not be greater than 50% of the chord length. Hinges or other parts of a component which occur at occasional cross-sections for connection purposes can be excluded from the projected lengths.

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20 hours ago, nav said:

So one person rowing machines aren't ok after all (so much for incomplete quotes) :D

Fixed it for you.

Unless you know of rowing machines that can be described as "grinding pedestals or winches that are operated by turning handles in a rotary motion with the hands." :huh:

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^

Try again

On 4/4/2018 at 9:01 AM, dogwatch said:

Good spot on 20.8. In fact "in a rotary motion" means rowing machines are also out to pump oil.

20.8* One or more force input devices that are designed to allow more than one crew member to supply power
to a common mechanical drive train, a common pressure supply line or a common control function must
be grinding pedestals or winches that are operated by turning handles in a rotary motion with the hands.
This does not prohibit the use of other force input devices that occasionally allow more than one crew
member to provide simultaneous power (e.g. helm wheels), providing that is not their usual mode of
operation.

*(no ganged up bikes for example)

 

20.8 One or more force input devices that are designed to allow more than one crew member to supply power

 - paraphrased:    any 'force input device' designed to be operated by more than one of the crew............or several linked devices allowing multiple crew to supply power

 

So this ^ clause at least, says nothing about how a one person hand-driven 'FID' that is not linked to any others shall be designed or used - yeah?

But this is going to be traditional so I'm sure we'll see......

image.png.b8e34fa5b0a572b29dfb323c7db6f6e8.png    

;)

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12 hours ago, nav said:

20.8 One or more force input devices that are designed to allow more than one crew member to supply power

 - paraphrased:    any 'force input device' designed to be operated by more than one of the crew............or several linked devices allowing multiple crew to supply power

So this ^ clause at least, says nothing about how a one person hand-driven 'FID' that is not linked to any others shall be designed or used - yeah?    

Paraphrasing should be shorter… ;-)

I guess you could use nunchucks/nunchaku or bull whips too, but what control are they going to operate?

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10 hours ago, Tornado-Cat said:

Why going that far, a grinder for 2 or more fits the definition.

Exactly.

The fact that they have defined it reasonably tightly doen't mean it will be an area of development...or contention, doubly so given the onboard power-pack

zzzzz....

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9 hours ago, Varan said:

Thanks for that

It seems that after their analysis North is still  fairly equivocal about the benefits, in this soft wing hybrid, of the inversion aspect so nicely demonstrated in the hard wing

The balance of the inversion and normal camber can in some conditions increase the boat’s performance.

Would they all be better off concentrating on the best functioning setup with this new endeavor before adding extra complexity - seeking the last x%?

image1.jpg

image2.jpg

 

But it's the AC so....

 

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One of the worst written rules I've ever seen, quite apart from the sheer stupidity of many proscribed aspects.  But yes, it's the AC...so that's all right then:(

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On 5/4/2018 at 11:40 AM, barfy said:

Figure 12.1: Foil geometry

looks like that to me, but I surely could be wrong.

 

Hmm ...

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18 hours ago, Xlot said:

 

Hmm ...

hmm what? the plane is wrong, but surely the foil wings won't have 1.1m in the vertical plane.

I can't find any measurements of the fore-aft box of the wing and flap box in the class rule. As in there are no plan view of the measurements of the foil wing provided.

So I am assuming that the view fore-aft, looking along the "Foil wing symmetry plane", with "400 mm extent of supplied foil arm", and a total of 1100 mm box described in figure 12.1, but with 14.8 limiting the flap to 50% of the foil and flap length, could give a total length of 1m.

Can we discuss this? I am happy to state when I am not sure of a statement, when i'm throwing an idea out for discussion. My bullshit meter extends to myself, unlike some other posters.

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there was only one person perfect, and we all know what happened to him.

link

 

jc.jpg

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2 hours ago, barfy said:

I can't find any measurements of the fore-aft box of the wing and flap box in the class rule. As in there are no plan view of the measurements of the foil wing provided.

It's 12.4. 

My understanding of the 1.1 m high transverse region is that it will accomodate a negative dihedral foil, with flaps not quite extending to tips - it's the only way to get to the max. 4 m span with significant flap deflection

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4 minutes ago, Xlot said:

It's 12.4.

so 2m?

with 50% flap? so 1m flap?

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13 minutes ago, barfy said:

so 2m?

with 50% flap? so 1m flap?

 

If one wanted that much - but as you said, it would probably result in a BAR-slow boat. Also, I must dust off my 1968 vintage copy of I.H.Abbott's Theory of Wing Sections, but I seem to remember that plain flaps considered were 30% chord. Thise were pre-CFD days, though

 

Aside, re aileron/flap: wonder if slotted flaps work in a liquid?

 

 

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12 hours ago, Xlot said:

 

If one wanted that much - but as you said, it would probably result in a BAR-slow boat. Also, I must dust off my 1968 vintage copy of I.H.Abbott's Theory of Wing Sections, but I seem to remember that plain flaps considered were 30% chord. Thise were pre-CFD days, though

 

Aside, re aileron/flap: wonder if slotted flaps work in a liquid?

 

 

You can have any flap percentage you want in a plain flap.  It just depends on what you want to accomplish and what the structural constraints are.  It's common for them to be in the 20% to 30% chord range, but they don't have to be.

Slotted flaps work just as well in liquid as in air. 

It's interesting that Richard Whitcomb's first supercritical airfoil design was actually a slotted section, and there are a lot of similarities between supercritical airfoil design and subcavitating hydrofoil design.  In both cases you're trying to keep the peak velocity from exceeding some threshold value, so the section shapes look a lot alike.  Whitcomb's slotted supercritical section would be a good starting point if you wanted to have high lift with a flap and a high incipient cavitation speed.

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On 4/5/2018 at 12:34 PM, rh2600 said:

 

There are 2 words on the above which suggests the class is doomed - "Martin Fischer". If there was ever somebody I would not want involved in the design of a foiling boat, it would be him. Has he ever got a foiling boat right first time? No, and in some cases, he hasn't got it right after 3 or 4 attempts. His A Class foilers have been a total failure, from the Mayfly (should have been called the Won'tFly), a number of attempts with the Paradox and now a less than promising start with the new DNA where he seems to have managed to make the boat slower rather than faster.

Fischer relies on his computer and CFD to design and forgets about the real world. He then argues long and hard why his modelling is right and real life is wrong (I kid you not) blaming everybody from the builders to the sailors. Classic example is A Class rudders where he insists in staying with L rudders because of the theoretical advantage. Forget that the loads on the upright are all on one side and the rudders flex all over the place because you cannot make them strong enough and thin enough.

The whole thing looks like a "camel" ( a horse designed by committee).It is full of compromises that were self imposed, such as a promise to go monohull, be faster than the AC50's, do away with hard wings, be able to hoist sails after a long tow out to sea and more. If the stories about the modifications being done to the AC50's for their new series are true, the AC75's won't be able to match their speed anyway.

So what we are left with is a compromised, extremely expensive boat that is failing to impress. Good job!

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The main question is not so much about Martin Fisher than to know than, who is Guillaume Verdier working for now.

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On 30/03/2018 at 1:19 PM, nav said:

5.2 In Rule 5.1, the terms in the column “Rule” have the following meaning:

(a) Open: The shape and construction is open to design, within the constraints specified for that com-
ponent within this AC75 Class Rule.

(b) Specified: The outer shape and some aspects of construction are specified by this AC75 Class Rule,
but other aspects of construction are open to design.

(c) Supplied: The component is supplied as standard to all Competitors. Modifications to the compo-
nents are prohibited except where specifically permitted by this AC75 Class Rule.

- who "supplies" ?

my guess is a (NZ?) manufacture under contract to COR/D, (or under contract to a daughter company they set up)

- who pays ? 

the Teams for sure

Somebody stands to be making good money from this. 

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5 hours ago, Basiliscus said:

You can have any flap percentage you want in a plain flap.  It just depends on what you want to accomplish and what the structural constraints are.  It's common for them to be in the 20% to 30% chord range, but they don't have to be.

Slotted flaps work just as well in liquid as in air. 

It's interesting that Richard Whitcomb's first supercritical airfoil design was actually a slotted section, and there are a lot of similarities between supercritical airfoil design and subcavitating hydrofoil design.  In both cases you're trying to keep the peak velocity from exceeding some threshold value, so the section shapes look a lot alike.  Whitcomb's slotted supercritical section would be a good starting point if you wanted to have high lift with a flap and a high incipient cavitation speed.

Very interesting link - thanks!

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6 hours ago, mad said:

Somebody stands to be making good money from this. 

It may well be that the guys from Core Composites get some work out of AC36 yet. They do have a nice autoclave waiting to bake some thing other than biscuits.

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10 hours ago, A Class Sailor said:

There are 2 words on the above which suggests the class is doomed - "Martin Fischer". If there was ever somebody I would not want involved in the design of a foiling boat, it would be him. Has he ever got a foiling boat right first time? No, and in some cases, he hasn't got it right after 3 or 4 attempts. His A Class foilers have been a total failure, from the Mayfly (should have been called the Won'tFly), a number of attempts with the Paradox and now a less than promising start with the new DNA where he seems to have managed to make the boat slower rather than faster.

Fischer relies on his computer and CFD to design and forgets about the real world. He then argues long and hard why his modelling is right and real life is wrong (I kid you not) blaming everybody from the builders to the sailors. Classic example is A Class rudders where he insists in staying with L rudders because of the theoretical advantage. Forget that the loads on the upright are all on one side and the rudders flex all over the place because you cannot make them strong enough and thin enough.

The whole thing looks like a "camel" ( a horse designed by committee).It is full of compromises that were self imposed, such as a promise to go monohull, be faster than the AC50's, do away with hard wings, be able to hoist sails after a long tow out to sea and more. If the stories about the modifications being done to the AC50's for their new series are true, the AC75's won't be able to match their speed anyway.

So what we are left with is a compromised, extremely expensive boat that is failing to impress. Good job!

Faster than the AC50s

That is were small minds immediately went, but it was never a stated goal AFAIK.

But to indulge for a moment, faster what? Reaching, VMG, up, down, time around the AC35 course, time around the AC36 course?? Pfft....

And now you shift the goal posts anyway and say they wont beat a secret class of modified boats that are clearly not AC50s - remember there's a rule that determines that.

You must mean the Spite Cup Class - modified also-ran carcases to indulge the expensive fantasies of those too timid to enter the AC

 

Agree Fischer may not have been a good call though ;)

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11 hours ago, Basiliscus said:

It's interesting that Richard Whitcomb's first supercritical airfoil design was actually a slotted section, and there are a lot of similarities between supercritical airfoil design and subcavitating hydrofoil design.  In both cases you're trying to keep the peak velocity from exceeding some threshold value, so the section shapes look a lot alike.  Whitcomb's slotted supercritical section would be a good starting point if you wanted to have high lift with a flap and a high incipient cavitation speed.

That's VERY intriguing. Thanks!

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11 hours ago, A Class Sailor said:

There are 2 words on the above which suggests the class is doomed - "Martin Fischer". If there was ever somebody I would not want involved in the design of a foiling boat, it would be him. Has he ever got a foiling boat right first time? No, and in some cases, he hasn't got it right after 3 or 4 attempts. His A Class foilers have been a total failure, from the Mayfly (should have been called the Won'tFly), a number of attempts with the Paradox and now a less than promising start with the new DNA where he seems to have managed to make the boat slower rather than faster.

Fischer relies on his computer and CFD to design and forgets about the real world. He then argues long and hard why his modelling is right and real life is wrong (I kid you not) blaming everybody from the builders to the sailors. Classic example is A Class rudders where he insists in staying with L rudders because of the theoretical advantage. Forget that the loads on the upright are all on one side and the rudders flex all over the place because you cannot make them strong enough and thin enough.

The whole thing looks like a "camel" ( a horse designed by committee).It is full of compromises that were self imposed, such as a promise to go monohull, be faster than the AC50's, do away with hard wings, be able to hoist sails after a long tow out to sea and more. If the stories about the modifications being done to the AC50's for their new series are true, the AC75's won't be able to match their speed anyway.

So what we are left with is a compromised, extremely expensive boat that is failing to impress. Good job!

Most of ETNZ's gains last time were made using computer simulation as opposed to full size testing/ training, which was what the other teams chose to do. When most thought they were "doing nothing in Auckland" with their shed doors consistently closed a lot of the time, ETNZ had leap frogged their opponents because they had better simulation tools. 

In terms of being faster than the AC50's, all that was stated was "the AC75's will be faster than the AC50's in certain conditions"

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2 hours ago, nav said:

Agree Fischer may not have been a good call though ;)

And, he's definitely not a Design Manager - worried for LR :(

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On 5/4/2018 at 4:34 AM, rh2600 said:

 

 

Barfy, will you be asking about flap chord there?

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^ if the weather is too rude to be on the water I will see if I can get a word in.

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On 4/7/2018 at 8:52 PM, Xlot said:

It's 12.4. 

My understanding of the 1.1 m high transverse region is that it will accomodate a negative dihedral foil, with flaps not quite extending to tips - it's the only way to get to the max. 4 m span with significant flap deflection

reading again this morning with a bit of time off:

My reading of 12.4 is the positioning of the foil in a box fore-aft, but not defining the chord of the foil-flap assembly.

And yes, the shaded region in fig 12.1 is projected to TRP,  which as you say, would accommodate dihedral.

My take-away this morning is 1.1m of wing, and flaps 50% of the wing's chord. So 1.5m wing + flap available.

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Wow these foils are getting seriously interesting.

@Basiliscus's https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720066117.pdf brings all sorts of possibilities, early lift off, increased velocity before cavitation, and I guess a few I don't see.

Oh the compromises ! Stability should be the main driver IMHO.

Big size possibilities as well.  So the software will need to be seriously good to predict these performances.

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22.3 A crew indication device must be incapable of measuring any part of the yacht state, unless it contains no electronic parts...

 

 

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57 minutes ago, barfy said:

22.3 A crew indication device must be incapable of measuring any part of the yacht state, unless it contains no electronic parts...

 

 

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In the 1970s we did a study of a fluidic flight control computer. Hm. Only one axis to monitor. Hm. Anybody remember how to build a mechanical rate gyro? Oh, this could be fun.

Cheers,

Earl

 

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On 4/8/2018 at 7:58 PM, sclarke said:

Most of ETNZ's gains last time were made using computer simulation as opposed to full size testing/ training, which was what the other teams chose to do. When most thought they were "doing nothing in Auckland" with their shed doors consistently closed a lot of the time, ETNZ had leap frogged their opponents because they had better simulation tools. 

No doubt about that, but it was because they were very good at understanding what could be achieved in the real world, so they didn't design stuff that couldn't be built to work. That is where Fischer always breaks down. What's the point in designing a set of rudders which perform great in the computer if you cannot build them like that in real life? Fischer has all the excuses, usually blaming somebody else for the problem. Some would say i am being harsh. He is a genuinely charming man who is very smart and certainly knows a lot more about boat and foil design than I do, but you need to look at his track record. While he would be one of the first people I would invite to give a teory lecture on foiling, he wouldn't be so high up the list on who to go to for design work.

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^ Not sure which element/s it was that ETNZ was testing last time, but the sailors were contributing some direct data from the 'destructive testing container'  - to help ensure designers didn't over-optimise presumably.....

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“16-18 knots of boat speed to get foiling” dan b. going to be a lot of non foiling racing 

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Ugh that was a hard stream to watch... I have up and will attempt again later... Poor video quality and Fischer's bird calls! Hehe

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1 hour ago, rh2600 said:

Ugh that was a hard stream to watch... I have up and will attempt again later... Poor video quality and Fischer's bird calls! Hehe

Hey, that's the new 'free to air' AC36 standard ;)

Good format though - hope they keep it going. (There's your feedback)

- PB signed (or at least confirmed as helm)

- Pure scow-bow :D not possible, but min' buoyancy requirements as anti dive measure

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On 02/04/2018 at 1:34 PM, hoom said:

And to think they could have just dialled back to a conventional ~60 foot cat...

 

4.2 The AC75 Class Yacht shall be propelled by sails only.

 

Regarding mainsails: I read it as allowing a relatively conventional double-luff, single surface windsurferish sail? I'm suspecting the relative simplicity, well known dynamics & weight advantage of that may come up trumps.

Nah, I think someone will find a way to make an inflatable wing sail that fall within the rules, shame outriggers are banned though.

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2 hours ago, Robsi524 said:

“16-18 knots of boat speed to get foiling” dan b. going to be a lot of non foiling racing 

Mhm, We'll probably get under that lol.

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2 hours ago, Robsi524 said:

“16-18 knots of boat speed to get foiling” dan b. going to be a lot of non foiling racing 

To be clear thats to get it foiling, not keep it foiling.

Have the start on a reach and you should be able to get up in most conditions and *hopefully* maintain flight throughout the course.

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2 hours ago, Robsi524 said:

“16-18 knots of boat speed to get foiling” dan b. going to be a lot of non foiling racing 

If you think about it, in Valencia it took about 10 seconds for the IACC V5's to get up to 10 knots of boat speed. They were much heavier than the 75's will be. 16-18 knots of boat speed really isn't that much.

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23 minutes ago, rh2600 said:

To be clear thats to get it foiling, not keep it foiling.

Have the start on a reach and you should be able to get up in most conditions and *hopefully* maintain flight throughout the course.

It will play out pretty much like the Super Foilers.

As long as you can hit the 16 knots on a beam reach the boats will be foiling to windward, they will just bear away, build to 16, accelerate to 20+ as the drag drops away and come back on the wind after each tack, it will make tacking more costly, but it's still going to be faster than not foiling.

The real question will be how much wind will they need to hit the 16 knots on a reach.

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that was painful, bandwidth from new cal better than at ETNZ base...not good. But i did work with ETNZ's head of IT, worst sys ad I've ever met, and i've worked with quite a few.

Too bad i was at work early, still don't know the chord length of foil/flap.

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7 hours ago, sclarke said:

If you think about it, in Valencia it took about 10 seconds for the IACC V5's to get up to 10 knots of boat speed. They were much heavier than the 75's will be. 16-18 knots of boat speed really isn't that much.

True. But if it requires them to go for a reach in order to fly upwind, it can quickly become bad for the competition. If one boat stop flying while the other continue, it will create huge gap and it doesn't align with close racing. Foiling tack will be even more critical than during the previous 2 cups.

That's actually my main concern, that boats should transition to fly mode in similar conditions and manage similar tacks in order to have good racing. It's not that fun to see 1km+ lead and it can quickly happen with this kind of boats.

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6 minutes ago, Lakrass said:

True. But if it requires them to go for a reach in order to fly upwind, it can quickly become bad for the competition. If one boat stop flying while the other continue, it will create huge gap and it doesn't align with close racing. Foiling tack will be even more critical than during the previous 2 cups.

That's actually my main concern, that boats should transition to fly mode in similar conditions and manage similar tacks in order to have good racing. It's not that fun to see 1km+ lead and it can quickly happen with this kind of boats.

Boundaries will keep the boats close.

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^ Add some big obstacles in the middle of the water (spectators boats to get them close to the action) and then you have flipper arcade mode races.

image.png.fa15d77a4168c33d81985df3d326ea45.png

That's an innovative race course... Don't ask who pay for the construction cost, it will be cover by ticket price (in theory)

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1 hour ago, barfy said:

that was painful, bandwidth from new cal better than at ETNZ base...not good. But i did work with ETNZ's head of IT, worst sys ad I've ever met, and i've worked with quite a few.

Too bad i was at work early, still don't know the chord length of foil/flap.

4 different wings per team, 20 flaps, lets go with 3 teams so far, how many permutations is that already?

Have you got a bet on this or something?

 

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1 hour ago, Lakrass said:

 It's not that fun to see 1km+ lead and it can quickly happen with this kind of boats.

Yeah I've watched all the races these boats have done as well - and you are so right

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5 minutes ago, nav said:

4 different wings per team, 20 flaps, lets go with 3 teams so far, how many permutations is that already?

Have you got a bet on this or something?

 

just wondering if we will see a 2m chord.

massive foils, low speed lift with some way of dealing with the speed.

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Sailing

Humans only: Cyborgs sidelined for America’s Cup

 

Although it’s a race of technology, Team New Zealand have taken steps to stop robots sailing in the next America’s Cup, and to give more power to the humans on board. Suzanne McFadden reports.

There’s a curious clause in the new class rule for the AC75 boat to be sailed in the next America’s Cup. It reads: “There shall be eleven crew members, unless reduced by accident, who shall all be human beings."

Emirates Team New Zealand’s technical director, Dan Bernasconi, chuckles at its mention. “It’s a little bit tongue-in-cheek”, he says.

“But you never know. People are always looking for the last bit of performance to get out of the boat. Whether anyone would turn up with a crew full of androids, who would know?” he says.

........

“The other great thing about it, is that it gets the sailors involved in the design process. Most of the designers here aren’t that good at driving the simulator. So you get the sailors involved right from the beginning, and then they understand the trade-offs of foil shapes and section shapes much better. And I think that leads to a much better boat.”

In the last Cup, Bernasconi would have three sailors on the sailing simulator. Helmsman Peter Burling would be holding a real steering wheel in front of a huge screen, with Blair Tuke manoeuvring the controls for the foils, and skipper Glenn Ashby moving the wing with an X-box controller – a gadget that transferred to the real boat and became known as Team NZ’s ‘secret weapon’.

“It meant that the first day out on the water, the X-box controller was already second nature to Glenn,” says Bernasconi, who admits they first experimented with a larger digger controller.

 

more....

https://www.newsroom.co.nz/2018/04/10/104123/cyborgs-sidelined-from-the-americas-cup

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OK, I give up. 22.3.b says:

must be incapable of measuring any part of the yacht state, unless it contains no electronic parts; [emphasis mine]

Why is that exception there?

Cheers,

Earl

 

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First iterations of a new design rule usually end up being primarily about the design and can end up with disparate performances (usually in favor of the defender). But, as the design rule matures, boats get closer and closer in performance and that is when you get the tight racing.

While I liked the foiling cats, I think it will very interesting to see who and how they make this thing work.

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3 hours ago, Earl Boebert said:

OK, I give up. 22.3.b says:

must be incapable of measuring any part of the yacht state, unless it contains no electronic parts; [emphasis mine]

Why is that exception there?

Cheers,

Earl

 

There are hints in the article I posted immediately above yours...checking what the rule writers were thinking seems like a good place to look for answers