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Boats and foils comparison


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Just a few interesting bits of the straight-line performances from today: Upwind /Downwind VMGs - race 1: Upwind /Downwind VMGs - race 2: Same story in both races actually.

Thanks to weta27's pics I have created an approximation of NZ's "BFB v2" foil. Main points: Foil area is almost the same, possibly even a smidge larger. Flaps have increased in area as

OK, it sounds like there's some interest in this topic, so here goes.   Any engineering effort starts by defining the requirements.  From this figure, it looks like the average foil area is 1.64

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15 minutes ago, Stingray~ said:

Flying too high for in those conditions? 

Flying too high? I don't think so. Great example of low, low riding, IMO

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35 minutes ago, Sailbydate said:

Flying too high? I don't think so. Great example of low, low riding, IMO

Yep, perhaps so.

Slightly off-topic but after weeks of reflection I am starting to think that GBR has a great balance going hull wise, for the extra RM to climb out onto the foils early in 6.5 knots, but with an end-plating skeg too, to achieve the same as what LR and ETNZ were apparently going after. 

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13 minutes ago, Stingray~ said:

Yep, perhaps so.

Slightly off-topic but after weeks of reflection I am starting to think that GBR has a great balance going hull wise, for the extra RM to climb out onto the foils early in 6.5 knots, but with an end-plating skeg too, to achieve the same as what LR and ETNZ were apparently going after. 

Still looks butt ugly though. 

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4 hours ago, Lickindip said:

here is a random question ... does anyone have access to the technical drawings for the 1 design parts ... in particular the Foil arms ???

"One hears" that you're starting a late entry team?

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10 hours ago, RMac said:

"One hears" that you're starting a late entry team?

on a side note, I'm looking to employ the following for a non-related project:

someone good with a chainsaw and nail gun, must be able to say "she'll be right" and "2 Easy" after given plans and instructions

2 people who go to the gym a lot, (experience with painting cars black and red is essential)

Crane driver:  not one of the "health and safety, this must be certified wank wank" types

someone whos got a camo steering wheel and able to work with water being splashed in their eyes

A coach - past team leader at Mcdonalds is a requirement

chief purchaser - we will give you a gift card to mitre 10 to get the supplies we need (they have better coffee then bunnings), you will also be required to hunt down the last packets of Paihia bombs for the sailing crew  Christmas party boat ride

PS: if the crane driver and camo wheel guy are the same person it will save my budget and ill offer you an extra chocolate fish a week

also looking at a volunteer who can go around the Firth of Thames and pick up a few floating mussel buoys under the disguise of cleaning up the harbour

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50 minutes ago, gungabow said:

Try this for now Lick

Top is original design , bott is revised

Funny how the revised section is larger. Poss scaled up to throw people like us

Ill keep an eye out for other stuff

57644428_ScreenShot2019-05-30at3_47_11PM.thumb.png.19d742fb150044fdd7f0e2c190d85531.png

574425409_ScreenShot2019-05-30at3_46_46PM.thumb.png.5c49ead4ac12b3c4b2e33d538ae5cfa4.png

cheers, more looking for the drawings with actual dimensions. Then I can draw the S shape accurately and be able to overlay that on some pictures ... maybe even 3d print a model

if anyone has autocad, solidworks or .STL models of an AC75 that would make life easy

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On 9/2/2020 at 10:33 PM, gungabow said:

Try this for now Lick

Top is original design , bott is revised

Funny how the revised section is larger. Poss scaled up to throw people like us

Ill keep an eye out for other stuff

57644428_ScreenShot2019-05-30at3_47_11PM.thumb.png.19d742fb150044fdd7f0e2c190d85531.png

574425409_ScreenShot2019-05-30at3_46_46PM.thumb.png.5c49ead4ac12b3c4b2e33d538ae5cfa4.png

Why the fuck did they decide to make it hollow besides control lines. No wonder it failed....

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1 hour ago, Raptorsailor said:

Why the fuck did they decide to make it hollow besides control lines. No wonder it failed....

Those two drawing are to scale too, so it also got bigger... the delta of engineering between the two is *massive*...

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2 hours ago, Raptorsailor said:

Why the fuck did they decide to make it hollow besides control lines. No wonder it failed....

Be fair. Everyone is a Genius with the benefit of 20/20 Hindsight. No one died. Solutions were found. 1st World problems and all that Jazz......

The boats are stil freakishly out there, and flipping impressive. No one has mentioned how much more complexity in construction a Hollow section is to manufacture, and the way that complex manufacture by nature allows the possibility of errors in manufacturing to creep in. Has there been any confirmation that the failure was attributed to just initial poor design or was manufacture also contributory? Whatever the actual and real causes, the fact that these arms are now providing reliable service needs recognition.

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2 hours ago, Raptorsailor said:

Why the fuck did they decide to make it hollow besides control lines. No wonder it failed....

The hell are you on about

Guess your no engineer

POP Quiz for ya

How light COULD you make a centerboard for a laser sailing in the Tokyo Olympics (if allowed).

Thought so , YOU DONT KNOW

Served

 

 

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from this Gtran 

https://translate.googleusercontent.com/translate_c?depth=1&nv=1&pto=aue&rurl=translate.google.com&sl=auto&sp=nmt4&tl=en&u=https://m.faz.net/aktuell/technik-motor/technik/abgefahrene-segeltechnik-vom-schwimmen-zum-fliegen-16939954-p2.html&usg=ALkJrhgmPgchd86g16S4QaZbr5ED3TTOkQ

According to Fischer, a “constant flight altitude of plus / minus 20 centimeters is ideal. However, this is not always possible with waves. If you manage to keep the distance between the hull and the water surface between 30 and 100 centimeters, that's not bad. "

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2 hours ago, Stingray~ said:

from this Gtran 

https://translate.googleusercontent.com/translate_c?depth=1&nv=1&pto=aue&rurl=translate.google.com&sl=auto&sp=nmt4&tl=en&u=https://m.faz.net/aktuell/technik-motor/technik/abgefahrene-segeltechnik-vom-schwimmen-zum-fliegen-16939954-p2.html&usg=ALkJrhgmPgchd86g16S4QaZbr5ED3TTOkQ

According to Fischer, a “constant flight altitude of plus / minus 20 centimeters is ideal. However, this is not always possible with waves. If you manage to keep the distance between the hull and the water surface between 30 and 100 centimeters, that's not bad. "

so 12 to 30 inches or basically under 1 meter.

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20 hours ago, Boink said:

Be fair. Everyone is a Genius with the benefit of 20/20 Hindsight. No one died. Solutions were found. 1st World problems and all that Jazz......

The boats are stil freakishly out there, and flipping impressive. No one has mentioned how much more complexity in construction a Hollow section is to manufacture, and the way that complex manufacture by nature allows the possibility of errors in manufacturing to creep in. Has there been any confirmation that the failure was attributed to just initial poor design or was manufacture also contributory? Whatever the actual and real causes, the fact that these arms are now providing reliable service needs recognition.

This, but my point is I'm not an engineer, but it is well known that hollow structures are not as strong as solid ones. And as far as I know foils in sailing in general tend to be solid. Why change something when it works. Sure innovation. You're right. But you're deciding to create a yacht where hitherto unseen loads are being carried by one part when other high performance yachts, notably Ultim's and IMOCA's where the consequences of failure could be much higher use solid sections on similar parts which carry similar loads. i know I've I've already said it, I'm not an engineer, but it's something that for me just doesn't make sense. Even when you factor in innovation. :/ 

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17 minutes ago, resist said:

@Lickindip found one of your gym guys for you

I think I need to stay away from the ones with questionable blood samples,

a couple of applicants have said they have exceptional results on Grinder and their swipe rate is high ... I don't quite understand so guessing its a language barrier thing

:lol::lol::lol::lol:

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Any ideas about this? From a friend, who is actually a flyboy:

 

”hey! hope your having a great weekend.. question ..
actually a beer bet... 
friend says that the trailing edge flaps on the foils will have a significant part on the aerodynamic load when said foil is out of the water .. negative camber to increase downforce on the windward foil will effect the balance of the boat..
I say BS ... The surface area of the foil is designed to operate at its optimum in the water, and will have little or no effect on the aero load of the foil.. 
what say you?
be advised this debate is with the wife!” 
 

 

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10 minutes ago, Stingray~ said:

Any ideas about this? From a friend, who is actually a flyboy:

 

”hey! hope your having a great weekend.. question ..
actually a beer bet... 
friend says that the trailing edge flaps on the foils will have a significant part on the aerodynamic load when said foil is out of the water .. negative camber to increase downforce on the windward foil will effect the balance of the boat..
I say BS ... The surface area of the foil is designed to operate at its optimum in the water, and will have little or no effect on the aero load of the foil.. 
what say you?
be advised this debate is with the wife!” 
 

 

stick a surfboard out the window of your car going down the motorway and change the angle bit by bit ... please report back with pictures

to say it has NO effect would be wrong.

is it something a team could use for stabilising or righting moment without any negative effects ... I don't see why not. weather it is a coincidence or not we have seen etnz with the raise arm flaps being in a non neutral position

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31 minutes ago, Lickindip said:

we have seen etnz with the raise arm flaps being in a non neutral position

Thnx, was curious about that. And agreed that there is RM to be had with neg attack at those speeds but the drag trade off is hard to figure.. 

Part of my mostly-fun response was:

“Wow, good question! 

In either the link above, epp11b, or the epp11a with Shirley, I was a touch surprised to hear Nick Holroyd who is now chief designer with Ineos say (iirc) that DRAG was going to be critical and that, despite water being some 800 times denser, the drag would be roughly 50-50 between hydro and aero.” 
 

^edit: silly font, phone..

 

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59 minutes ago, Stingray~ said:

Any ideas about this? From a friend, who is actually a flyboy:

 

”hey! hope your having a great weekend.. question ..
actually a beer bet... 
friend says that the trailing edge flaps on the foils will have a significant part on the aerodynamic load when said foil is out of the water .. negative camber to increase downforce on the windward foil will effect the balance of the boat..
I say BS ... The surface area of the foil is designed to operate at its optimum in the water, and will have little or no effect on the aero load of the foil.. 
what say you?
be advised this debate is with the wife!” 
 

 

I'm with you, Stinger. Too small a surface area to affect boat balance in any measurable way. Two crew members changing sides in manoeuvers would have a far greater impact on aero drag, IMO.

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17 minutes ago, Stingray~ said:

Thnx, was curious about that. And agreed that there is RM to be had with neg attack at those speeds but the drag trade off is hard to figure.. 

Part of my mostly-fun response was:

“Wow, good question! 

In either the link above, epp11b, or the epp11a with Shirley, I was a touch surprised to hear Nick Holroyd who is now chief designer with Ineos say (iirc) that DRAG was going to be critical and that, despite water being some 800 times denser, the drag would be roughly 50-50 between hydro and aero.” 
 

^edit: silly font, phone..

 

makes sense, water is 800x denser but you probably have 800x more surface area / frontal area of boat in the wind

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25 minutes ago, Lickindip said:

makes sense, water is 800x denser but you probably have 800x more surface area / frontal area of boat in the wind

Thnx, bingo, it must be why Nick said it to Shirley. The ‘surfboard out the window at 50’ is an interesting concept too :D I drive a drop-top at mostly those speeds and am happy to keep even just my hands inside. 
 

Good chance that the guy on the flight joystick is aware of the auto-response happening on the flying foil’s flap, and of the modulating RM/drag effect at accelerating AWS, much like in a sophisticated aircraft. 

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8 hours ago, Raptorsailor said:

This, but my point is I'm not an engineer, but it is well known that hollow structures are not as strong as solid ones. And as far as I know foils in sailing in general tend to be solid. Why change something when it works. Sure innovation. You're right. But you're deciding to create a yacht where hitherto unseen loads are being carried by one part when other high performance yachts, notably Ultim's and IMOCA's where the consequences of failure could be much higher use solid sections on similar parts which carry similar loads. i know I've I've already said it, I'm not an engineer, but it's something that for me just doesn't make sense. Even when you factor in innovation. :/ 

Err..... Control Lines maybe???? Pushing the envelope??? Because they wanted to?? A hundred other reasons......

This does not move us forward. We do not conclusively know know if the failure was purely engineering failure (some one, in fact many, thought that Hollow would be up to the job - a design of such a mission critical piece does not fall under the gaze of just one engineering designer to achieve sign off) or whether the design was just too complex to build....... But probably a bit of both.

And bearing in mind how far behind the 8 ball the failure of the orginal design and built piece placed the entire AC programme - a simpler, more easily built and possibly oversized redesign would be much easier to get group sign off upon subsequently........

I take it that you have not sat in upon many high stakes meetings where engineers are asked to put their Testicles on the Chopping Block (proverbially speaking)  - failure a second time was NOT an option. 

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10 hours ago, Raptorsailor said:

it is well known that hollow structures are not as strong as solid ones.

Depends what you mean by 'strong'.

 

For a given weight a properly designed hollow structure will be significantly more rigid (eg the difference between solid laminate fibre glass & foam core or a sheet of corrugated cardboard vs flat board)

 

Clearly the first version was trying to meet an aggressive weight target for the required rigidity/load case within a thin (compared to say a multihull crossbeam) foil profile.

In the end they accepted a big weight hit & went nearly entirely solid to get the strength/rigidity required without fattening up the foil.

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Ok, now that LR B1 is back under wraps, which B2 from UK or AM do you think adapted more of the LR style?  

1926110979_AMvsUKb2inwrap.thumb.jpg.dbc027d3270b59a603ba2072d6c3eea7.jpg

 

 

Here are some pics/screen shots of LR B1.  I didn't realized the LR had such flat sides tot he hull (like UK B2).  .

1336259834_LRB1wrap6.jpg.fe9e6e589af785cbe4cefc2f70dcad7d.jpg

how nice of them to outline the crew area with the "no-step" box

430443517_LRB1wrap2.thumb.jpg.3cd49a1244f85e3c5f4789d6f2951448.jpg322055602_LRB1wrap3.thumb.jpg.6cff35dddd0cae0550aa070287851adb.jpg402783804_LRB1wrap4.thumb.jpg.8d14f08ce889da704b2ded8856ee0cd4.jpg

hopefully this is just a "big lift" that takes it to a more secure spot for the long hall to NZ

1304599357_LRB1wrap1.thumb.jpg.df2ff830519c13bd096a5eb9b798d9ea.jpg

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I bet LR’s B2 hull looks close to their B1’s hull. 
 

As Simmer said, the big changes on B2’s will involve boards and updated control systems. The hull changes will be visible and fun but the degree to which teams can snap tacks and jibes with increasing regularity will be a little more difficult to discern. 

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6 hours ago, The_Alchemist said:

Ok, now that LR B1 is back under wraps, which B2 from UK or AM do you think adapted more of the LR style? 

Here are some pics/screen shots of LR B1.  I didn't realized the LR had such flat sides tot he hull (like UK B2). 

how nice of them to outline the crew area with the "no-step" box

hopefully this is just a "big lift" that takes it to a more secure spot for the long hall to NZ

 

Any sign of foils or foil arms?

Agreed on the flat sides. The radius at the sheer line still seems a bit sharp to the AWA in my eye, I guess it's a tradeoff of trying to keep flow moving aft or over the deck. 

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Perhaps this has been covered...  Or is in the rules... Yeah, I have not read all of it, nor do I remember everything I have read.

But, what is the reason that all the foils have the T part always with the same angle for both sides? Why can't one of the sides of the T be at a slightly different angle from the main strut? And, they seem to always be symmetrical? Is that required or is there some reason? I guess it would/should be balanced, but with different angles and sizes and shapes, seems like there might be some different dynamics that might be advantageous.

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3 minutes ago, nroose said:

Perhaps this has been covered...  Or is in the rules... Yeah, I have not read all of it, nor do I remember everything I have read.

But, what is the reason that all the foils have the T part always with the same angle for both sides? Why can't one of the sides of the T be at a slightly different angle from the main strut? And, they seem to always be symmetrical? Is that required or is there some reason? I guess it would/should be balanced, but with different angles and sizes and shapes, seems like there might be some different dynamics that might be advantageous.

They must be symmetrical across the axis formed by the connection with the foil arm. 

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4 minutes ago, nroose said:

Perhaps this has been covered...  Or is in the rules... Yeah, I have not read all of it, nor do I remember everything I have read.

But, what is the reason that all the foils have the T part always with the same angle for both sides? Why can't one of the sides of the T be at a slightly different angle from the main strut? And, they seem to always be symmetrical? Is that required or is there some reason? I guess it would/should be balanced, but with different angles and sizes and shapes, seems like there might be some different dynamics that might be advantageous.

because there is a rule saying they must be symmetrical

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Just for fun, I will throw this out here again as a possible example of a coming rule-beater and game winner, again avoiding the intent of the Rule.

ENTZ fans went bezerk while claiming OR had a Herbie in AC34 running a supposedly illegal rule intent bender but applauded it forever when ETNZ actually did deploy a computerized flight controller in AC35, along with applauding how ETNZ pulled off blowing through the ‘manual’ intent of that Rule, going with bicycles and follow-the-dot touchpads.
 

‘Innovative’ or aggressively legalistic? 


The 27.8 stipulation should have included the word ‘only’ as in ‘ONLY the following may be powered by the FCS’s batteries: .. ‘

44E5A8DC-8225-4210-949A-B24C4D5C24C2.thumb.png.e3e05e2e1a03dcb986d90affe8eca729.png

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11 minutes ago, Stingray~ said:

Just for fun, I will throw this out here again as a possible example of a coming rule-beater and game winner, again avoiding the intent of the Rule.

ENTZ fans went bezerk while claiming OR had a Herbie in AC34 running a giant the rule intent but applauded it when ETNZ actually did deploy a computerized flight controller in AC35, along with applauding how ETNZ pulled off blowing through the ‘manual’ intent of that Rule, going with bicycles and follow-the-dot touchpads. ‘Innovative’ or aggressively legalistic? 


The 27.8 stipulation should have included the word ‘only’ as in ‘ONLY the following may be powered by the FCS’s batteries: .. ‘

44E5A8DC-8225-4210-949A-B24C4D5C24C2.thumb.png.e3e05e2e1a03dcb986d90affe8eca729.png

Well I guess you could add an iPhone charging port. Maybe a Nepresso?

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4 minutes ago, uflux said:

Well I guess you could add an iPhone charging port. Maybe a Nepresso?

:) 

Since this boat is so power hungry, basically a battery powered boat, I think it’s a reasonable example of a clause that will be exploited. Why not power you wing and other controls off that truly massive battery pack if you are willing to flaunt the intent and can secretly get away with it using that ‘Only-absent’ verbiage? Of course they will!

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9 minutes ago, See Level said:

But 23.1 does use "only" Screenshot_20200914-172528.thumb.png.61590741a497bab348aaa185882f0891.png

Thanks, may try to wrap my head around that later. What I posted about power-sucking was one of probably many loophole examples that team may create game-changers out of, in their attempts to be ‘innovative.’ Power is, again, an obvious target example. As are ‘Herbie’ openings this time..

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1 hour ago, Stingray~ said:

Just for fun, I will throw this out here again as a possible example of a coming rule-beater and game winner, again avoiding the intent of the Rule.

ENTZ fans went bezerk while claiming OR had a Herbie in AC34 running a supposedly illegal rule intent bender but applauded it forever when ETNZ actually did deploy a computerized flight controller in AC35, along with applauding how ETNZ pulled off blowing through the ‘manual’ intent of that Rule, going with bicycles and follow-the-dot touchpads.
 

‘Innovative’ or aggressively legalistic? 


The 27.8 stipulation should have included the word ‘only’ as in ‘ONLY the following may be powered by the FCS’s batteries: .. ‘

44E5A8DC-8225-4210-949A-B24C4D5C24C2.thumb.png.e3e05e2e1a03dcb986d90affe8eca729.png

27.8 Unless otherwise indicated

i.e unless the FCS specification says "plugin Nespresso here" you can't plug anything else into it.

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15 minutes ago, Lickindip said:

27.8 Unless otherwise indicated

i.e unless the FCS specification says "plugin Nespresso here" you can't plug anything else into it.

Okay, no Rules lawyer here but hopefully there’s a larger point: Someone will bend the rules again, as usual. Hopefully this time they (whoever does it) won’t make a mockery of the whole thing!

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13 hours ago, Lickindip said:

27.8 Unless otherwise indicated

i.e unless the FCS specification says "plugin Nespresso here" you can't plug anything else into it.

Nope. It says these can be plugged in ..... unless the FCS specs (once finalised) do not allow (one or more) of these to be plugged in.

But neither clause limits options to only those listed (although that was probably the intent).

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15 hours ago, Stingray~ said:

Just for fun, I will throw this out here again as a possible example of a coming rule-beater and game winner, again avoiding the intent of the Rule.

ENTZ fans went bezerk while claiming OR had a Herbie in AC34 running a supposedly illegal rule intent bender but applauded it forever when ETNZ actually did deploy a computerized flight controller in AC35, along with applauding how ETNZ pulled off blowing through the ‘manual’ intent of that Rule, going with bicycles and follow-the-dot touchpads.
 

‘Innovative’ or aggressively legalistic? 


The 27.8 stipulation should have included the word ‘only’ as in ‘ONLY the following may be powered by the FCS’s batteries: .. ‘

44E5A8DC-8225-4210-949A-B24C4D5C24C2.thumb.png.e3e05e2e1a03dcb986d90affe8eca729.png

I love this, raising a valid point sure, but coating it in Spin-boy slime.

Pure revisionism, false equivalency, mixed with BS, but may suck in a noob or 2

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9 minutes ago, Stingray~ said:

So that says: 

The weight limit for the AC75 is 6520 kg (14,374 lbs.), that’s not including sails or crew

So is there a separate weight limit on sails? Else you could make some sails with lead lining (say) near the bottom. Normally any high up weight is disastrously bad, but in this case it would still provide righting moment. So a heavy weather sail could provide an advantage by being heavy

Admittedly it would be put more load on mast base and other gear, but I wonder

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17 hours ago, Stingray~ said:

Just for fun, I will throw this out here again as a possible example of a coming rule-beater and game winner, again avoiding the intent of the Rule.

ENTZ fans went bezerk while claiming OR had a Herbie in AC34 running a supposedly illegal rule intent bender but applauded it forever when ETNZ actually did deploy a computerized flight controller in AC35, along with applauding how ETNZ pulled off blowing through the ‘manual’ intent of that Rule, going with bicycles and follow-the-dot touchpads.
 

‘Innovative’ or aggressively legalistic? 


The 27.8 stipulation should have included the word ‘only’ as in ‘ONLY the following may be powered by the FCS’s batteries: .. ‘

44E5A8DC-8225-4210-949A-B24C4D5C24C2.thumb.png.e3e05e2e1a03dcb986d90affe8eca729.png

Adding lead to a king post in a one design class was, and still is, illegal.

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3 hours ago, MR.CLEAN said:

not sure what you are talking about

 

He made a disgusting racial slur saying that anyone black with a gold chain was a pimp, it was reported yet fuck all happened

 I wasn’t alone in finding it offensive but like the shit with salty seacock the post remained 

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38 minutes ago, JALhazmat said:

He made a disgusting racial slur saying that anyone black with a gold chain was a pimp, it was reported yet fuck all happened

Indio posted a bunch of even-worse racist crap directed at me back-when, amazingly while he was convinced that I am black! F’ing nutcase... But I didn’t complain to the mods or anything, just laughed at it, amazed at the idiocy. 

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4 minutes ago, Stingray~ said:

Indio posted a bunch of even-worse racist crap directed at me back-when, amazingly while he was convinced that I am black! F’ing nutcase... But I didn’t complain to the mods or anything, just laughed at it, amazed at the idiocy. 

Well silly fucking me for bothering..

 

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10 hours ago, Stingray~ said:

Indio posted a bunch of even-worse racist crap directed at me back-when, amazingly while he was convinced that I am black! F’ing nutcase... But I didn’t complain to the mods or anything, just laughed at it, amazed at the idiocy. 

I use to post here in the past. Some of the racists comments I’ve seen here puts Fox News to shame. Was one of the reasons Why I stopped, 

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15 minutes ago, mako23 said:

I use to post here in the past. Some of the racists comments I’ve seen here puts Fox News to shame. Was one of the reasons Why I stopped, 

According to Stingers its just funny...

the mods don’t do anything either do not surprised it proliferates/keeps coming back.

the last “ban” was a week if that, he was welcomed back under the same user name so there is no deterrent.

you put someone real name up though and it’s instant delete so clearly they more important.. 

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2 hours ago, JALhazmat said:

According to Stingers its just funny...

the mods don’t do anything either do not surprised it proliferates/keeps coming back.

the last “ban” was a week if that, he was welcomed back under the same user name so there is no deterrent.

you put someone real name up though and it’s instant delete so clearly they more important.. 

In my opinion part of it may be due to cultural differences.  I’ve got dual UK and NZ passports and have lived for long periods in both countries. What would be considered humor in NZ is not the same as the UK. Also people in the UK have seen  more of the damaging side of racism, and are more more aware of its dangers. Quote Steven Laurence case for example. In NZ In such a case would not resulted in much action. I’m not saying that NZ is a racist paradise, it’s not at all.  Serious cases of Racism is treated with no tolerance. It’s just people have a lot thicker skin here. When in the UK I quickly have to moderate my speech to as not cause offense. 

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Unfortunately for Indio, salty etc this Isn’t an NZ forum, so any cultural bias/allowance can fuck off.

Although the Ed, mods, clean etc seem to give it pretty free pass so maybe it’s ok after all? 
 

what I have learned Recently though is people don’t care and don’t want it brought up or you get labelled as pathetic, boring, whining etc. 
do best we all stfu and let them crack on. 

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11 minutes ago, JALhazmat said:

Unfortunately for Indio, salty etc this Isn’t an NZ forum, so any cultural bias/allowance can fuck off.

Although the Ed, mods, clean etc seem to give it pretty free pass so maybe it’s ok after all? 
 

what I have learned Recently though is people don’t care and don’t want it brought up or you get labelled as pathetic, boring, whining etc. 
do best we all stfu and let them crack on. 

I just block any messages from Indio

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FWIW I didn't see the posts in question, but as a general principle racism is completely unacceptable, and so complaining if it happens must be the right thing to do. 

The alternative is just like saying that cheating is unacceptable, but protesting someone using an engine in a sailing race is just pathetic whining

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from ‘Maintaining altitude’ at https://seahorsemagazine.com/current-issue/160-content/october-2020/947-maintaining-altitude


Similar examples elsewhere are rare, apart from the America’s Cup which has led the foiling charge and seen huge leaps in performance over a short space of time. So how much has the Cup influenced or informed the new look Imoca 60s?

‘The Cup has certainly helped to develop tools and design processes to predict the boat’s behaviour and therefore the simulation of the loads,’ Manganelli says. ‘That’s been a big contribution. In addition, the ability to predict the flying attitude of the boats has also been improved thanks to the work carried out in the Cup.

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12 hours ago, JALhazmat said:what I have learned Recently though is people don’t care and don’t want it brought up or you get labelled as pathetic, boring, whining etc. 

 

Not all of us JALhazmat I think it’s good that you highlight racist Behaviour. I don’t see you as whining or boring at all. 

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2 hours ago, Stingray~ said:

from ‘Maintaining altitude’ at https://seahorsemagazine.com/current-issue/160-content/october-2020/947-maintaining-altitude


Similar examples elsewhere are rare, apart from the America’s Cup which has led the foiling charge and seen huge leaps in performance over a short space of time. So how much has the Cup influenced or informed the new look Imoca 60s?

‘The Cup has certainly helped to develop tools and design processes to predict the boat’s behaviour and therefore the simulation of the loads,’ Manganelli says. ‘That’s been a big contribution. In addition, the ability to predict the flying attitude of the boats has also been improved thanks to the work carried out in the Cup.

Improves my attitude too. I like this cup cycle.

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Again with the spray under tow comparison. And the bow down attitude of AM, surely not compensating for excess lift as mentioned. These boats have heaps of flap to do just that, if AM need to pitch the boat cause their flaps are out of range they got big problems.

Screenshot_20200917-220825_YouTube.jpg

Screenshot_20200917-220806_YouTube.jpg

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50 minutes ago, Lickindip said:

one of the best square on pictures I can get other then them healing away from the camera

foil is outside the box ... but my guess is 200mm +

image.png.21e2307a4fa88bb424e1f786875fb7ce.png

Absolutely love the pattern you superimpose here again.

My guess is that the shot not is perfectly square on, with the extending arm magnifying the parallax of where the wings are. 

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I am trying to figure out the reasons why a team would choose a T vs an anhedral (A) foil.  

Let's ignore the bulb and foil arms to just focus on the angle of the foils.  If we assume that each wing of the foil produce 100 units of lift at a constant speed.  Two wings on the foil will give 200 units of lift.  Let's start with the foil arm in the straight up vertical position (perpendicular to the surface of the water).   The T foils would be parallel to the surface of the water so all of the lift would be in the vertical direction.  For the anhedral (A) foil let's say the angle of the foils are 15 degrees down (rough estimation of AM foil angle).  Since the lift from the foil is normal to the plane of the foil, the force can be split between the vertical and horizontal directions.  If we just assume that the foils of both the T and A are identical in shape and size and only differ in the angle they are attached to the foil arm.  Also, let's ignore any forces that are generated by the foil arms themself because they would be identical for both the T and A foils in our example.

1369416190_ScreenShot2020-09-17at11_28_08PM.thumb.jpg.e335355f499d4a6df1485e304f8c64de.jpg

I did some force diagrams (it has been a long time since I tried this) and built the following chart.  I calculated the forces in the vertical and horizontal directions as the foil arm is moved in 5 degrees increments.  

It looks like the T foil (green bars) generates more vertical and horizontal forces at every angle of the foil arm.  

1518532362_ScreenShot2020-09-17at11_46_53PM.thumb.jpg.e3bd1c9d636b01aca728c69b5e44caed.jpg

Discussions around an anhedral foils/wings mention that they tend to improve turning and reduces sideways slippage/stability.  I did not look into the differences in the angles of attack, etc that each type of foil can give.  

I am by no means an expert, just trying to understand the advantage/disadvantages and why they are choosing the various foils.

Please feel free to correct my work or add to the discussion.

 

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25 minutes ago, The_Alchemist said:

trying to understand the advantage/disadvantages and why they are choosing the various foils.

The horizontal results are curious. You'd thing the anhedrals would give more lateral resistance. There must be something desirable about the anhedrals, as they've all tried them. In fact, flat foils have been in the minority across the fleet. Might have something to do with the different drag characteristics of each setup?

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44 minutes ago, Horn Rock said:

The horizontal results are curious. You'd thing the anhedrals would give more lateral resistance. There must be something desirable about the anhedrals, as they've all tried them. In fact, flat foils have been in the minority across the fleet. Might have something to do with the different drag characteristics of each setup?

If the outer foil is set horizontal and the inner foil is angled down the inner foil will assist lift to windward so there will be less leeway.  For vertical lift you only need enough lift and clearly they have enough.

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1 hour ago, The_Alchemist said:

I am trying to figure out the reasons why a team would choose a T vs an anhedral (A) foil.  

Let's ignore the bulb and foil arms to just focus on the angle of the foils.  If we assume that each wing of the foil produce 100 units of lift at a constant speed.  Two wings on the foil will give 200 units of lift.  Let's start with the foil arm in the straight up vertical position (perpendicular to the surface of the water).   The T foils would be parallel to the surface of the water so all of the lift would be in the vertical direction.  For the anhedral (A) foil let's say the angle of the foils are 15 degrees down (rough estimation of AM foil angle).  Since the lift from the foil is normal to the plane of the foil, the force can be split between the vertical and horizontal directions.  If we just assume that the foils of both the T and A are identical in shape and size and only differ in the angle they are attached to the foil arm.  Also, let's ignore any forces that are generated by the foil arms themself because they would be identical for both the T and A foils in our example.

1369416190_ScreenShot2020-09-17at11_28_08PM.thumb.jpg.e335355f499d4a6df1485e304f8c64de.jpg

I did some force diagrams (it has been a long time since I tried this) and built the following chart.  I calculated the forces in the vertical and horizontal directions as the foil arm is moved in 5 degrees increments.  

It looks like the T foil (green bars) generates more vertical and horizontal forces at every angle of the foil arm.  

1518532362_ScreenShot2020-09-17at11_46_53PM.thumb.jpg.e3bd1c9d636b01aca728c69b5e44caed.jpg

Discussions around an anhedral foils/wings mention that they tend to improve turning and reduces sideways slippage/stability.  I did not look into the differences in the angles of attack, etc that each type of foil can give.  

I am by no means an expert, just trying to understand the advantage/disadvantages and why they are choosing the various foils.

Please feel free to correct my work or add to the discussion.

 

Somehow, I believe your base assumptions are off.

Firstly, all foils are constrained by the Rule Designated Foil Limits Box. Because drag characteristics are determined by Aspect Ratio, with the Higher the aspect ratio leading to lower drag characteristics. Therefore it is safe to assume that ALL foils, whether Aneheral or T will have the Tips of their Horizontals buried into the outermost limits of that Rule defined Box. The actual Foils of an Anhedral Foil are longer in length and of a higher Aspect ratio, so the base Lift characteristics are NOT comparable to a T foil at any point. Furthermore, any Anhedral Foil will have different Drag Characteristics to Standard T Foils. Your calculations do not reflect the Drag side of equation, only the Lift side. 

You theory lacks rigour or even evenhandness by trying to suggest that they are of equivalence to start with. On Paper Anhedrals seem superior to T foils and can be orientated to give good lift in mant aspects of flight. Yet we are increasingly seeing Flatter foils being trialled as we get to the pointy end of the campaigns. 

I believe that with the recent but regular photos showing T foils aerating the outermost horzontal to quite some significant degree, that this is no longer accidental but a deliberate ploy by both teams to seek a lower drag mode of sailing in powerful conditions. But consider trying to aerate the outermost (most Leeward) element of an Anhedral foil.

Consider that after take off and light wind conditions, no team is running the foil arm connection element in a vertical fashion. All the powered up sailing shows how they spread their Foils Arms to the widest possible stance to maximise RM. With an Anhedral Foil, that months back, we all assumed would remain immersed. The Outermost element would be approximately Horizontal and the inner element would be 30 degrees or so down from the waterplane surface. The Outermost would be providing Optimum Lift Vectors whilst the inner element would be more effective at Leeway resistance. Independant control of the two surfaces would give good and varied flight control.

However, in the hunt for greatest RM and Least Drag, the teams have learnt that minimum immersion of both Main Foil Arms (and their connecting foils