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1 minute ago, Ncik said:

They're only hulls for a small percentage of a race, pre start. The rest of the time they're fuselages.

Which the designers have said are still significant for aero & end-plating. GB's keel will compromise its ability to turn but they sure as hell put it there for a reason, end-plating being the most obvious explanation

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shes legit ... foil arm looks to be in the front end of the box ... opposite of all other teams ... what are we going to read into that?

ETNZ are probably favorites .....but win or lose....Team New Zealand have firmly established themselves as the all time great AC nation in the modern era.   From the time they first emerged, they have

Slowly working through yesterday's lot

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11 hours ago, mogs said:

Waterline shape looks intended to satisfy 11.11 with minimum volume (which has instead been shifted to the keel):

Even after reacting to your earlier post I still didn't really absorb that.

It explains why TNZ has the flat bit immersed as well, the rule prevents winding up like Out95 or the very slender works of @Groucho Marx

 

Despite my disparaging mention of Bolger Boxes I actually think this B2 looks really good.

I like the bow, the flat belly style should let it skip/bounce off the water instead of digging in.

That 'wave' in the bottom would be nearly impossible to feel if you ran your hand along it, probably near impossible to spot if it wasn't high-gloss finished or at a less glancing angle.

Not a huge fan of those foils at least in terms of detail, may be working similar to TNZ Whompers ie gets a bigger chunk of the foil operating deeper & another chunk more vertical.

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4 minutes ago, enigmatically2 said:

Which the designers have said are still significant for aero & end-plating. GB's keel will compromise its ability to turn but they sure as hell put it there for a reason, end-plating being the most obvious explanation

Agreed, Ineos definitely have a longer skeg/keel than AM and I'm sure they have their reasons, which would be weighted heavily to aero and rule compliance only.

The only reason the steps are there is for rule compliance.

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13 hours ago, MaxHugen said:

I can't get my head around any of the hull below the waterline!

They better hope they don't have to change direction while the hull is in the water during prestart.   That bitch would be sucky to turn.

 

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8 minutes ago, Ncik said:

They're only hulls for a small percentage of a race, pre start. The rest of the time they're fuselages going at relatively slow air speeds.

The steps are only to meet rules requirements.

correct but the hull shapes , which are very different determine the positioning of  the foil arms etc etc which deternmines  the way the boat will be able to fly.

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11 minutes ago, enigmatically2 said:

Which the designers have said are still significant for aero & end-plating.

Arenthey referring to all the bumps below the gunwale or the hull as a whole? As a whole then yes, hull has huge aero implications,  below gunwale, skeg/keel is the primary aero consideration...and frontal area and trailing edge.

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1 minute ago, hairyharford said:

correct but the hull shapes , which are very different determine the positioning of  the foil arms etc etc which deternmines  the way the boat will be able to fly.

The rules determine the position of foil arms, hulls are designed around that.

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13 minutes ago, hoom said:

I like the bow, the flat belly style should let it skip/bounce off the water instead of digging in.

I think flat is sticky at that size, not bouncy.  But then it's supposed to be out of the water 100% of the time.

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32 minutes ago, enigmatically2 said:

Which the designers have said are still significant for aero & end-plating. GB's keel will compromise its ability to turn but they sure as hell put it there for a reason, end-plating being the most obvious explanation

Is there any airflow diagram around that shows how the underside of a hull affects the sail as an end plate?

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36 minutes ago, astro said:

I think flat is sticky at that size, not bouncy.  But then it's supposed to be out of the water 100% of the time.

the video of it tow testing yesterday post #2976 with the hull contacting the water skimming looked smooth, it looked like a deliberate test to see interaction between hull and water contact.

you would be able to get a pressure/lift reading to see how much lift comes off the foils and onto the hull and the other way (pressure onto the foils as it lifts clear)  to see the effect of touch down and lift off vs the hull on B1 as well as how that transition is best handled in terms of trimming, what angle on the foils and rudder are needed, the cross over point  to foiling /non foiling.

the lack of wake coming off the stern  is a huge change.

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1 hour ago, Ncik said:

The rules determine the position of foil arms, hulls are designed around that.

yes but the hull shape determines the various key points which then determine other positions its not the IOR  but it does look a little like they have tweeked the shape to gain an advantage in positioning of other items/apendages  not just to improve aero/endplate effects

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On 10/15/2020 at 4:39 PM, JALhazmat said:

 INEOS employ a series of very tall people to work on the support boats so to make sure the boat is at a comfortable working height they need a cradle 4 m off the ground so they don't get bad backs from crouching down.

its the B2 cradle.

:lol::lol:

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On 10/16/2020 at 9:55 PM, Zeusproject said:

Wow.      Where do you start with that concept 

Agreed, not sure what to say to any of this...............apart from its going to be interesting!:blink:

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On 10/17/2020 at 1:50 AM, Sugarscoop said:

Looks like they may have been talking with Ludde and taken a leaf out of the successful CQS design......

CQS-laying-over-on-Sydney-Harbour-–-ROLEX-Kurt-Arrigo.jpg

That program was far from successful. 

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I want to know what's going on at the forward end of that boom - from the aft view it looks rigid/unarticulated which just seems crazy given how shit AM B1 looked with that set-up. However, one of @mikenz2 photos hints at that box hiding something slightly more interesting as it extends further fore/aft than I originally thought... Mikenz2 - do you have any more photos of this area?

ineos b2 boom.jpeg

ineos b2 boom2.jpeg

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4 hours ago, Ncik said:

As far as the wind is concerned, the only major difference i can see between the 2 B2s is the length of the skegs.

Maybe they're dummy foils, but we haven't seen anything similar on the other boats. If they're not dummies then they'll probably be fiddled with within the mass change limits, for sure.

Have you even looked at the two hulls?

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31 minutes ago, NZK said:

I want to know what's going on at the forward end of that boom - from the aft view it looks rigid/unarticulated which just seems crazy given how shit AM B1 looked with that set-up. However, one of @mikenz2 photos hints at that box hiding something slightly more interesting as it extends further fore/aft than I originally thought... Mikenz2 - do you have any more photos of this area?

ineos b2 boom.jpeg

ineos b2 boom2.jpeg

It’s articulated 

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4 hours ago, Ncik said:

As far as the wind is concerned, the only major difference i can see between the 2 B2s is the length of the skegs.

There is probably 4m^2  of Sail area underneath  Rita ! so possibly a bit of a difference for the wind

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Speaking of hull shapes...

“Today I'm not impressed. I didn't come home shocked, in short, after seeing them." Max Sirena.

There is a link to the original interview there for those more versed in Italian.

 

Edit... just read the luna rossa thread... sorry for the repost.

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2 hours ago, Ex-yachtie said:

As a UK passport holder and rabid NZ ETNZ supporter I still want the Brits to do well. I hope they win  the Prada cup and then be beaten by ETNZ. Rumors about Ineos B1 being a dog now have more credence. If B1 wasn’t a dog then why build something so different.  Ineos B2 is another design that’s at the edge of what’s normal. It’s like Ineos have gone from one extreme to the other. It doesn’t fill me with confidence. Nothing would make me happier to see B2 to be competitive. Sadly a lot of weird boats have come out the UK in regards to the the America’s Cup and a history of under performance. Not all boats have been extreme, but too many have been dogs. If you think this is UK bashing nothing could be further from the truth.  Just a sad lament of previous challengers and a sickening feeling history will repeat itself. 
 

Inneos team hat on now and ETNZ hat put down

FFS that last really competitive boat we have was the J endevour which was faster the than the defender. Even then we managed to fuck it up, with the professional crew going on strike and then been replaced by Amateurs. We seem always hell bent trying to rely on a technology advantage. We have good sailors and are second to none. Why don’t we trust them a little more. Nor do we need foreign talent. The Hiring of Nick Holroyd.....why hire him. He seems very good at producing losers. We have the Best F1 teams in the country with the best technology in the world. I’d rather trust them than some prick from NZ

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18 hours ago, NZK said:

I want to know what's going on at the forward end of that boom - from the aft view it looks rigid/unarticulated which just seems crazy given how shit AM B1 looked with that set-up. However, one of @mikenz2 photos hints at that box hiding something slightly more interesting as it extends further fore/aft than I originally thought... Mikenz2 - do you have any more photos of this area?

ineos b2 boom.jpeg

ineos b2 boom2.jpeg

What's with the big box? It's got matching pinstripes..but really, wouldn't you build an egg fairing onto it?

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It’s articulated. 

i was told to shut up about the box lol

its either staying on or it’s just there to cover off the mechanism. And they made it ( the cover)pretty

arent there rules against covering up bits though? I know it applies to hulls etc but deck gear too? 

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15 minutes ago, JALhazmat said:

It’s articulated. 

i was told to shut up about the box lol

its either staying on or it’s just there to cover off the mechanism. And they made it ( the cover)pretty

arent there rules against covering up bits though? I know it applies to hulls etc but deck gear too? 

Good question.

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21 minutes ago, JALhazmat said:

its either staying on or it’s just there to cover off the mechanism. And they made it ( the cover)pretty

Doesn't look like this box has a hole for the mast to pass through or any interface on the top. So except if the mast is not located at the end of this boom (the rule doesn't allow for many alternatives), then this box is just a cover and removable.

We don't have much to wait as first sail is due soon.

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1 hour ago, barfy said:

What's with the big box? It's got matching pinstripes..but really, wouldn't you build an egg fairing onto it?

Looks very interesting, hopefully it’s a box of tricks that gives a speed advantage 

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6 hours ago, barfy said:

What's with the big box? It's got matching pinstripes..but really, wouldn't you build an egg fairing onto it?

I was assuming it was a cover they put on when the rig was un-stepped and that it was both protection and anti-spy.

Perhaps if you can prove the cover is needed for weather-proofing then it's allowable???

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GB's underwater profile makes me wonder how well each team will perform in low wind conditions. With a minimum wind speed set at 6kn for races, and as these boats need around 19kn boat speed to get onto foils (or 16kn using both foils, as Xlot mentioned), they could be forced to race in displacement mode at times. Less wind during summer apparently, according to weatherspark:

image.png.a7d0df44c89f6bd152d85b015ade45f0.png

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On 10/18/2020 at 7:45 PM, Basiliscus said:

You can think of the local velocities of the strut and the foil as adding together at the junction.  Picture the surfaces glowing and lighting up each other.  The more acute the angle between them, the more the mutual influence will be.  Opening up the junction will raise the speed for cavitation onset.  Higher velocities in the junction also make for more skin friction drag there.

Gull Wings - pros / cons / nasty habits? - WattFlyer RC Electric Flight  Forums - Discuss radio control eflight

 

To accommodate a folding wing the designers considered retracting the main landing gear rearward but, for the chord of wing that was chosen, it was difficult to make the landing gear struts long enough to provide ground clearance for the large propeller. Their solution was an inverted gull wing, which considerably shortened the required length of the struts.[24] The anhedral of the wing's center-section also permitted the wing and fuselage to meet at the optimum angle for minimizing drag, without using wing root fairings.[24] The bent wing, however, was heavier and more difficult to construct, offsetting these benefits.

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19 minutes ago, MaxHugen said:

The Corsair was designed with the inverted "gull wing" to reduce the length of the landing gear, desirable for carrier landings. designing-bent-wing-bird 

An interesting read, thank you.

I misunderstood your summary but essentially the propeller needed to be large and the wings needed to meet the fuselage at 90deg to reduce drag (all in the pursuit of speed).  That meant that the landing gear needed to be long to reach the ground, making it heavy.  The bent wing brings the landing gear closer to the ground, shortening its length, making it lighter and faster.

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2 hours ago, NZK said:

I was assuming it was a cover they put on when the rig was un-stepped and that it was both protection and anti-spy.

Perhaps if you can prove the cover is needed for weather-proofing then it's allowable???

To be fair if Prada can cover their boom arrangement then I am sure a lawyer could make a case for the box 

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I think you'll find that it's 'added coverings' that are the concern. If something is used on the boat in that form it's not an issue, but if you deliberately cover something after the fact, then you have a problem.

121817875_757908878099240_3398027942713660665_o.jpg

;)

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56 minutes ago, Ex-yachtie said:

An interesting read, thank you.

I misunderstood your summary but essentially the propeller needed to be large and the wings needed to meet the fuselage at 90deg to reduce drag (all in the pursuit of speed).  That meant that the landing gear needed to be long to reach the ground, making it heavy.  The bent wing brings the landing gear closer to the ground, shortening its length, making it lighter and faster.

Also, a short landing gear made for longer folding wings > more compact deck parking

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1 hour ago, SCARECROW said:

exactly what does a bowman do on a boat where you're not allowed forward of the mast while racing? 

They get to see how truly unimportant everyone else's job aboard is. As in, "All you fuckers have to do is point in the right direction, steer and trim the thing".

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1 hour ago, SCARECROW said:

exactly what does a bowman do on a boat where you're not allowed forward of the mast while racing? 

On LR you may also be required to look for floating bits and pieces of the bow :D

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12 hours ago, MaxHugen said:

The Corsair was designed with the inverted "gull wing" to reduce the length of the landing gear, desirable for carrier landings.

That, but the main reason was to clear the huge prop from hitting the deck.

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1 hour ago, Horn Rock said:

That, but the main reason was to clear the huge prop from hitting the deck.

Must have been a successful design as there are so many gull wing aircraft around.  Copied endlessly!

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1 hour ago, astro said:

Must have been a successful design as there are so many gull wing aircraft around.  Copied endlessly!

The Luftwaffe knew they were onto something with the JU87 Stuka dive bomberStuka1.jpg.fc5c214db7ed382ee04d62f497907048.jpg

 

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On 10/17/2020 at 4:34 PM, Lakrass said:

Around 12min mark, boat expected on the water Tuesday or Wednesday...
Interesting to hear constant communication between ribs and "pilot" (at 39min), is that allowed during match?

Any news on when she is going to get out sailing? I am guessing all the commissioning must have been completed by now or are they still fiddling with her on the dock? 

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I think it will work well in light conditions...I would rather this design than the previous version.   The foil will still be there and as soon as it starts moving it will generate some lift. The wetted surface and drag are going to be far less... Stability stationery is obviously compromised.  Boats like your dart 18  tack okay without centreboards, your not designing a boat that's easy to sail.

I would love to see the mechanism inside the hydrofoil if they have taken the flap around the corner, That's the part that will win or lose them the race.  

I remember hearing ben say "Luna Rossa are fast" Looking how similar the design is and how they have copied them. I'm guessing what he really said was" their a lot faster than us"

 

 

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1 hour ago, Laurence said:

I would love to see the mechanism inside the hydrofoil if they have taken the flap around the corner,

I don't think they can do that... it would be 2 foil flaps per wing, which is not permitted under the Rules.
15.2 Each foil shall include two foil flaps, one lying entirely on one side of the foil wing symmetry plane, and one lying entirely on the other side of the foil wing symmetry plane.

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6 hours ago, Indio said:

The Luftwaffe knew they were onto something with the JU87 Stuka dive bomberStuka1.jpg.fc5c214db7ed382ee04d62f497907048.jpg

 

I thought the gull-wing this was to reduce the length of the undercarriage, as they were fitting monster engines and propellers and didn't want big long heavy undercarriages.  Drag wise you don't see many Gliders or airliners with a gull-wing design, If it saved 5% all of them would have it.

The only thing I can think of is that you're normally healed over, the inverted Y allows them to run the foil shallower without the tip emerging, the closer to the surface smaller Wingtip vortices and therefore less drag. 

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15 minutes ago, JALhazmat said:

AM think that INEOS have got it around the corner. they have better pics than we do on here.

IF they have then it wont be on the boat if its illegal 

They could have a flexible rubber joint between the flaps, this might allow them to class it as a single flap. 

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10 minutes ago, Laurence said:

I thought the gull-wing this was to reduce the length of the undercarriage, as they were fitting monster engines and propellers and didn't want big long heavy undercarriages.  Drag wise you don't see many Gliders or airliners with a gull-wing design, If it saved 5% all of them would have it.

The only thing I can think of is that you're normally healed over, the inverted Y allows them to run the foil shallower without the tip emerging, the closer to the surface smaller Wingtip vortices and therefore less drag. 

Why do airliners have gull-wings? - Quora

Slingsby Kirby Gull - Wikipedia

DFS Reiher - Wikipedia

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1 hour ago, JALhazmat said:

AM think that INEOS have got it around the corner. they have better pics than we do on here.

IF they have then it wont be on the boat if its illegal 

Interesting, but surely it only needs a cut between the two on the plane of symmetry to then make it legal.

All the teams (I think( have at times run asymmetric foils anyway. So they have all broken that one

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22 minutes ago, enigmatically2 said:

All the teams (I think( have at times run asymmetric foils anyway. So they have all broken that one

Haven't seen any asymmetric foils? Unless you're referring to a different foil on each foil arm, for comparative testing purposes?

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Surprisingly, the almighty Wikipedia has a short but comprehensive piece on Gull Wings.

Both normal and inverted designs had some sort of advantages for the given planes, like wing tip clearance for gliders or prop clearance for fighters, but they all came with a drag to lift penalty. Keep in mind, the 1930s and 40s were still pioneering days in aircraft design and aerodynamics.

 

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So why have the GB designers put one their PR show.if it has a drag-to-lift penalty

They must think there is an advantage, even if they don't think those are their race foils (which I am sure they are not)

I can't see how they would have better performance for cavitation. They could be better for stability but these boats are generally looking fairly stable now, so i doubt that. But there has been a lot of talk about deliberately coming to the surface to reduce drag, and I can see that potentially here. At low speeds you have the full width, but once your speed climbs, you bring the foil close to the surface and 1/3 of the GB foil comes out completely  far more so than on a straight foil.

Make sense?

 

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Just now, enigmatically2 said:

So why have the GB designers put one their PR show.if it has a drag-to-lift penalty

They must think there is an advantage, even if they don't think those are their race foils (which I am sure they are not)

I can't see how they would have better performance for cavitation. They could be better for stability but these boats are generally looking fairly stable now, so i doubt that. But there has been a lot of talk about deliberately coming to the surface to reduce drag, and I can see that potentially here. At low speeds you have the full width, but once your speed climbs, you bring the foil close to the surface and 1/3 of the GB foil comes out completely  far more so than on a straight foil.

Make sense?

 

Also foil sections and material technology has come on a bit since the 40s never mind one is for flying a d operating at a different speed range. 

but hey the internet/Wikipedia says it’s shit so there we have it. 
 

as a small rebuttal ( albeit irrelevant) currently the fastest monohull foiler (kites) all of the fastest brands/designs all use a gull wing foil.  All of which also breach the tip without stalling, this is more to applying more rake to the mast and promoting windward heel and a better angle upwind.

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32 minutes ago, enigmatically2 said:

So why have the GB designers put one their PR show.if it has a drag-to-lift penalty

They must think there is an advantage, even if they don't think those are their race foils (which I am sure they are not)

I can't see how they would have better performance for cavitation. They could be better for stability but these boats are generally looking fairly stable now, so i doubt that. But there has been a lot of talk about deliberately coming to the surface to reduce drag, and I can see that potentially here. At low speeds you have the full width, but once your speed climbs, you bring the foil close to the surface and 1/3 of the GB foil comes out completely  far more so than on a straight foil.

Make sense?

 

Maybe the British have been watching and observing everybody else without chewing through the foil allocation. 

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2 hours ago, enigmatically2 said:

So why have the GB designers put one their PR show.if it has a drag-to-lift penalty

They must think there is an advantage, even if they don't think those are their race foils (which I am sure they are not)

I can't see how they would have better performance for cavitation. They could be better for stability but these boats are generally looking fairly stable now, so i doubt that. But there has been a lot of talk about deliberately coming to the surface to reduce drag, and I can see that potentially here. At low speeds you have the full width, but once your speed climbs, you bring the foil close to the surface and 1/3 of the GB foil comes out completely  far more so than on a straight foil.

Make sense?

 

All Teams have one or more variants of the gull type and I can only guess why they tried them. Simple answer: Because they could and they wanted to find out about any possible advantages or drawbacks and how to include them in the complete package.

I have to add that I am in no way as deep into the theory or design process as the guys actually designing, building and testing the boats (and foils).

These boats and foils and everything that follows are also pioneering territory. Of course everything and anything gets built and tested in the entirely new context of an AC75 racer, if only to confirm better or lesser concepts and then work from there.

One point that has been discussed earlier was that Y-foils have an advantage of less turbulence/dirty drag at the joint because of the wider angles. Totally makes sense to me. Straight(ish) foils seem to be less complicated to build, also a valid point.

Then, cavitation or ventilation are two things that are beyond my knowledge. I know quite a bit about performance gliders, but very little about submerged wings.

 

I watch and learn, and sometimes I try to share an observation. I am in no way trying to build a better boat or foil than the AC teams, which brings me to:

 

2 hours ago, JALhazmat said:

Also foil sections and material technology has come on a bit since the 40s never mind one is for flying a d operating at a different speed range. 

but hey the internet/Wikipedia says it’s shit so there we have it. 
 

as a small rebuttal ( albeit irrelevant) currently the fastest monohull foiler (kites) all of the fastest brands/designs all use a gull wing foil.  All of which also breach the tip without stalling, this is more to applying more rake to the mast and promoting windward heel and a better angle upwind.

1) Undoubtably true!

2) You have overblown this one, sorry. That wiki piece talks (very briefly) about designs that are 70-80 years old and have not or very rarely been used later, probably for a reason? Also, that wiki thing is about old airplanes, not modern foils in the water.

3) Good point and I believe this is where today's work is: building a usable package from bits and pieces that probably don't make much sense as a standalone or in in different packages. The AC75 put everything up to trial again and will bring any number of surprising results (Who here has anticipated Britannia's keel?!)

 

And just to state the obvious: I am NOT entering the traditional know-it-all pissing contest. I have more questions than answers on these boats and try to fill in with what little I know about wings or foils. :)

 

 

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2 hours ago, JALhazmat said:

You came here for that? 
not lending credence to the informed kiwi critiquing theory espoused by @Horn Rock are you? 

That's why etnz have delayed their launch. They were due to splash this week,but are feverishly working to glue a big flat skeg on the boat.

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19 minutes ago, barfy said:

That's why etnz have delayed their launch. They were due to splash this week,but are feverishly working to glue a big flat skeg on the boat.

Nah the delay is figuring out the loss of revenue after getting fucked by the oh so lovely max.. and how to explain it to the city. 
 

sticking bits on boats will be child’s play compared to that 

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6 hours ago, JALhazmat said:

You came here for that? 
not lending credence to the informed kiwi critiquing theory espoused by @Horn Rock are you? 

Intuitive assessment.  Sometimes they are the best.  Who knows what our brains process.  They are still trying to build equivalent computers!

I remember taking my daughter aged 8 to the Auckland Museum.  There is a Japanese Zero and a Spitfire on display in two rooms.

"Dad I like the Spitfire it looks better".

She's a damn good sailor too!

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