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Classic AC Skullduggery

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ya heard that's what deano broke the other day? 

teams sure seem quiet about it. no gag rule, perhaps they would have something to say rather than leak it to....you? a newbie on SA?

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1 hour ago, I ride bikes said:

The one design foil cant system is causing issues for 2 teams.

And you never broke a crank arm, or your own arm?

On yer electric bike, I would say...

 

 

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2 hours ago, barfy said:

ya heard that's what deano broke the other day? 

teams sure seem quiet about it. no gag rule, perhaps they would have something to say rather than leak it to....you? a newbie on SA?

Just thought people here might find it interesting.  

Unsure why being a noob on these forums matters.  

Meh

 

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1 hour ago, Fiji Bitter said:

And you never broke a crank arm, or your own arm?

On yer electric bike, I would say...

 

 

Never broke my arm though 

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There are some sad posters around here that seem prone to being abusive in general and being a newbie gives them an excuse.

Please ignore the rudeness and give us more details about the foil arm rumors.

 

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If rumors were about foil arms, I’d be concerned. But the FCS is agricultural enough that all teams have hydraulic resources more than adequate to fix glitches, if any

 

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there probably wont be any problems with electrical systems, hardware, software, or firmware in a salty wet environment:)

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8 hours ago, I ride bikes said:

Just thought people here might find it interesting. 

Yeah. We might, if we heard something, IRB. What exactly have you heard, mate?

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11 hours ago, I ride bikes said:

The one design foil cant system is causing issues for 2 teams.

 

Very interesting, especially in light of AM and Te Aihe both evidently limping home on different days in the last 5-6 days..

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other than someone saying " is causing issues " ... is there any evidence?

teams limping home could be anything from batteries frying them themselves / broken foil control / hydraulic leak / jimmys camo wheel is ready to install / lunch time

pure speculation without any offer of reason

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9 minutes ago, Lickindip said:

other than someone saying " is causing issues " ... is there any evidence?

teams limping home could be anything from batteries frying them themselves / broken foil control / hydraulic leak / jimmys camo wheel is ready to install / lunch time

pure speculation without any offer of reason

"Issues" doesn't necessarily mean breakages - could simply be something we can all see in the videos, maybe the cant system is not responsive fast enough during manoeuvers which could be a big deal. Not sure whether the Class Rule empowers a team to resize their hydraulic systems to deliver more oil to speed up the system...

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AM has been ripping the course in big airs over the past week, there can’t be too much wrong with that boat. 

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58 minutes ago, Stingray~ said:

AM has been ripping the course in big airs over the past week, there can’t be too much wrong with that boat. 

Could also be the most obvious of problems. The same one Oracle had. Optimal performance in conditions outside of race conditions. It has been noted that Defiant has been sailing in big breeze that often is higher than the wind limits set for racing.

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48 minutes ago, Forourselves said:

Could also be the most obvious of problems. The same one Oracle had. Optimal performance in conditions outside of race conditions. It has been noted that Defiant has been sailing in big breeze that often is higher than the wind limits set for racing.

Agreed, since the Match will likely be raced in lighter conditions than the CSS. Hopefully not at the very-very bottom like what (by fluke) happened in Bermuda, but AM’s B2 is going to be designed for lighter air than what B1 was, for damn sure! 

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1 hour ago, Forourselves said:

Could also be the most obvious of problems. The same one Oracle had. Optimal performance in conditions outside of race conditions. It has been noted that Defiant has been sailing in big breeze that often is higher than the wind limits set for racing.

They may as well have some fun in it before it becomes the party barge in a month or so...

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8 minutes ago, NZL3481 said:

They may as well have some fun in it before it becomes the party barge in a month or so...

It’s possible they will race B1 in the ‘Christmas’ regatta but since B2 is arriving this early then there’s a stronger chance that B1 will be a party barge within a month, as you say. 
 

I’m curious about if Ineos B1 will ever hit the water again, or even get shipped to AKL. Does it even measure? 

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2 hours ago, Indio said:

"Issues" doesn't necessarily mean breakages - could simply be something we can all see in the videos, maybe the cant system is not responsive fast enough during manoeuvers which could be a big deal. Not sure whether the Class Rule empowers a team to resize their hydraulic systems to deliver more oil to speed up the system...

one design = no mods without everyone agreeing

if one team can make it work why would they allow modifications to improve other teams performance?

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3 hours ago, Sailbydate said:

Yeah. We might, if we heard something, IRB. What exactly have you heard, mate?

Bleeding pressure under full load.  

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If a one design hydraulic component is not "adequate for the job", does anyone have a clue as to how a challenging team would go about forcing an upgrade to the design?

 

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6 minutes ago, P Flados said:

If a one design hydraulic component is not "adequate for the job", does anyone have a clue as to how a challenging team would go about forcing an upgrade to the design?

 

I'm sure if its undersize and prone to failure all teams will want it changed so no problem, but to 'resize' the system for performance gains, I doubt it will happen this cycle.

my only concern with the one design system is - can it be recharged while the boat is on its side

with etnz's capsize we saw a minimal movement of the arms after the topple over with no visual attempt at self-righting. I can only assume as they had just come out of a manoeuvre that they were out of hydro and the boat being horizontal didn't allow them to recharge the system. 100% speculation I do admit

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58 minutes ago, Stingray~ said:

I’m curious about if Ineos B1 will ever hit the water again, or even get shipped to AKL. Does it even measure? 

Does anyone care?

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1 hour ago, Stingray~ said:

It’s possible they will race B1 in the ‘Christmas’ regatta but since B2 is arriving this early then there’s a stronger chance that B1 will be a party barge within a month, as you say. 
 

I’m curious about if Ineos B1 will ever hit the water again, or even get shipped to AKL. Does it even measure? 

No idea, but I know B2 is getting flown here.

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1 hour ago, Stingray~ said:

It’s possible they will race B1 in the ‘Christmas’ regatta but since B2 is arriving this early then there’s a stronger chance that B1 will be a party barge within a month, as you say. 
 

I’m curious about if Ineos B1 will ever hit the water again, or even get shipped to AKL. Does it even measure? 

it would have had to at one stage or be pretty close to it.

Ineo's B1 was sent (and sailed) to Italy in preparation for the world series which it would have needed a cert

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18 minutes ago, NZL3481 said:

Does anyone care?

Wtf are we here for, if not to yak mostly about AC75’s? 
 

AM’s B2 is on a flight to AKL and so questioning other teams’ plans is perfectly reasonable. 
 

Ineos has a terrific base, 2nd only to the ETNZ Palace, and so they could obviously house both their boats. I’m simply throwing out the possibility that we’ll never see the Ineos B1 even reach AKL, they could be done with it. And yes, including as one possibility that it wouldn’t even measure, meaning it’s useless as a backup for that reason too. For sure their B2 will arrive sooner, either way, what does that tell you? 

Got anything better to add to the conversation? I’ll wait.... 
 

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41 minutes ago, Stingray~ said:

I’m simply throwing out the possibility that we’ll never see the Ineos B1 even reach AKL, they could be done with it. And yes, including as one possibility that it wouldn’t even measure, meaning it’s useless as a backup for that reason too. For sure their B2 will arrive sooner, either way, what does that tell you? 

Got anything better to add to the conversation? I’ll wait.... 
 

That's a pity, because the Ineos B1 is probably a better party barge than the American one...

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4 minutes ago, NZL3481 said:

That's a pity, because the Ineos B1 is probably a better party barge than the American one...

:D 
 

yep, could be

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1 hour ago, Stingray~ said:

Wtf are we here for, if not to yak mostly about AC75’s? 
 

AM’s B2 is on a flight to AKL and so questioning other teams’ plans is perfectly reasonable. 
 

Ineos has a terrific base, 2nd only to the ETNZ Palace, and so they could obviously house both their boats. I’m simply throwing out the possibility that we’ll never see the Ineos B1 even reach AKL, they could be done with it. And yes, including as one possibility that it wouldn’t even measure, meaning it’s useless as a backup for that reason too. For sure their B2 will arrive sooner, either way, what does that tell you? 

Got anything better to add to the conversation? I’ll wait.... 
 

We may not see it sailing, but it will get shipped to NZ. If a boat sinks like One Australia did, they’ll still need one to sail however off the pace it may be. 

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I want to see it sailing here, if only to learn the answer to that elusive, eternal question:

- when pigs will fly.

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1 hour ago, XPRO said:

“Honestly , I was just riding along...”

Hukked it off a 50cm kicker.  Pretty disappointing to have it snap.  Warraneeee!  

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58 minutes ago, Forourselves said:

We may not see it sailing, but it will get shipped to NZ. If a boat sinks like One Australia did, they’ll still need one to sail however off the pace it may be. 

They’re allowed to two boat test against themselves, right?  Good base to compare from.

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3 minutes ago, Teaky said:

They’re allowed to two boat test against themselves, right?  Good base to compare from.

Nope, no two boat testing allowed for the Challengers.

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3 hours ago, Lickindip said:

one design = no mods without everyone agreeing

if one team can make it work why would they allow modifications to improve other teams performance?

IF the issue is the speed of the cant system, then it makes sense for all of them to agree to any necessary improvements. Unless one of the 4 is quite happy in which case they might not be too amenable to any improvements.

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3 hours ago, I ride bikes said:

Bleeding pressure under full load.  

That's not unexpected when they can set their system pressure to relieve at 600bar/8700psi!! Sounds like either the seals in the actuators or the couplings in the plumbing are not able to handle 600bar. This was a risk with not permitting variable-displacement hydraulic pumps under Class Rule - so they'll only be running with  fixed-displacement gear pumps and dead-heading the system at 600bar...

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11 minutes ago, Indio said:

That's not unexpected when they can set their system pressure to relieve at 600bar/8700psi!! Sounds like either the seals in the actuators or the couplings in the plumbing are not able to handle 600bar. This was a risk with not permitting variable-displacement hydraulic pumps under Class Rule - so they'll only be running with  fixed-displacement gear pumps and dead-heading the system at 600bar...

Don't have the rule here on my phone but I remember a couple of fcs system or software updates in the timetable. Are we past the final revision?

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22 minutes ago, barfy said:

Don't have the rule here on my phone but I remember a couple of fcs system or software updates in the timetable. Are we past the final revision?

The version I checked for the hydraulic system pressure in Class Rules ver1.10.

600bar is a very high pressure for any hydraulic system. They might have designed the smallest pair of hydraulic cylinders they could get away with (weight savings), and then ramped up the system pressure to generate the power needed to move the arms. A 2" piston at 600bar will generate 17t of force (allowing for 30% losses), so the pair will have plenty of grunt. They can drop the system pressure down to 400-420bar and still get enough grunt, and will also improve the speed of the arms..

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2 hours ago, Indio said:

IF the issue is the speed of the cant system, then it makes sense for all of them to agree to any necessary improvements. Unless one of the 4 is quite happy in which case they might not be too amenable to any improvements.

have you not seen any videos of all 4 teams where they tack and gybe? ETNZ in particular tacking on the spot after going around the bottom mark

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3 hours ago, Forourselves said:

Nope, no two boat testing allowed for the Challengers.

Seems strange given they have all the data plugged into simulators...  they can test against that I suppose!

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5 minutes ago, Teaky said:

Seems strange given they have all the data plugged into simulators...  they can test against that I suppose!

Personally, I would've enjoyed the teams two boat testing, but the protocol forbids teams lining up 2 AC75's in an organised manner. The Defender is allowed, but only during the period of the CSS. Whether they do or not is another question.

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“Organized manner” I wonder how soon we’ll see that tested...

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54 minutes ago, Teaky said:

“Organized manner” I wonder how soon we’ll see that tested...

Well, as Hutch pontificated smilingly, if you have a fast car and you see another fast car on the motorway, you naturally drive up to it and pull up alongside - and then take it from there B). That wouldn't be an encounter of an "organised manner"...

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"31/08/2020 27.9 Rules Committee FCS system updates frozen."

AC class rule v 1.9

So I guess if you were gonna have a bitch at the fcs yesterday would be a good time to get amongst it.

 

 

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On 9/1/2020 at 4:51 PM, Forourselves said:

Personally, I would've enjoyed the teams two boat testing, but the protocol forbids teams lining up 2 AC75's in an organised manner. The Defender is allowed, but only during the period of the CSS. Whether they do or not is another question.

I think we saw that question answered this morning with TeKahu wrapped in plastic.

Theres's enough talent in the team to run two AC75's.

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1 minute ago, NZL3481 said:
On 9/1/2020 at 6:51 PM, Forourselves said:

Personally, I would've enjoyed the teams two boat testing, but the protocol forbids teams lining up 2 AC75's in an organised manner. The Defender is allowed, but only during the period of the CSS. Whether they do or not is another question.

I think we saw that question answered this morning with TeKahu wrapped in plastic.

Theres's enough talent in the team to run two AC75's.

Would be happy to speculate the ETNZ Simulator has become sophisticated enough (and maybe more importantly, understood and proven) to do away with the need for two boat testing.

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5 minutes ago, NZL3481 said:

You are always wanting to verify your simulator/simulated data in the field. Always.

Yeah. But you don't need two boats to do that, NZL. Just the Simulator, the boat and some time on the water.

The Simulator has already been proven and so has Te Aihe's relative performance, I'd suggest. Did I read somewhere recently that ETNZ reckon they are 20% better than the sim VPP's? Prolly made that up! ;-)

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On 8/31/2020 at 11:15 PM, Indio said:

That's not unexpected when they can set their system pressure to relieve at 600bar/8700psi!! Sounds like either the seals in the actuators or the couplings in the plumbing are not able to handle 600bar. This was a risk with not permitting variable-displacement hydraulic pumps under Class Rule - so they'll only be running with  fixed-displacement gear pumps and dead-heading the system at 600bar...

I thought is was seal failure as well having built custom shocks. It is a smaller part than that and apparently both teams sailing are having tons of maintenance since the the parts list is “locked”. 

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42 minutes ago, Sailbydate said:

Yeah. But you don't need two boats to do that, NZL. Just the Simulator, the boat and some time on the water.

The Simulator has already been proven and so has Te Aihe's relative performance, I'd suggest. Did I read somewhere recently that ETNZ reckon they are 20% better than the sim VPP's? Prolly made that up! ;-)

I doubt highly that simulation and performance are 20% apart. If that's the case, there's even more cause for two boat testing to better verify the simulation tools. I would think a difference of 2% would be a pretty good difference between simulation and actual, but the goal would be to get the simulation tools somewhere near 0.2% different from verified to be a great tool...

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1 hour ago, Sailbydate said:

Would be happy to speculate the ETNZ Simulator has become sophisticated enough (and maybe more importantly, understood and proven) to do away with the need for two boat testing.

Of Course, they are so good that we should just run the cup races on it.

If it is so perfect, then why did NZ build a test boat (that they originally didn't think was necessary) and why did NZ need to change the foil designs?

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39 minutes ago, NZL3481 said:

I doubt highly that simulation and performance are 20% apart. If that's the case, there's even more cause for two boat testing to better verify the simulation tools. I would think a difference of 2% would be a pretty good difference between simulation and actual, but the goal would be to get the simulation tools somewhere near 0.2% different from verified to be a great tool...

I don't think the difference was between simulation and performance, I understood the references were made to speed on the water at time of launching and now. Sure there is some different hardware being used now but the learning how to sail and get the performance out of it was where big gains were made.

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38 minutes ago, The_Alchemist said:

Of Course, they are so good that we should just run the cup races on it.

If it is so perfect, then why did NZ build a test boat (that they originally didn't think was necessary) and why did NZ need to change the foil designs?

1) We want to see a boat race and it wouldn't be DoG compliant - boat race and all. :D

2) Te Aihe was on a container ship to nowhere - and back, eventually

3) ETNZ needed a platform to continue testing systems, foils etc

Two boat testing is outmoded by technology and too expensive, when the Simulator provides a proven alternative. Perhaps it's another one of those "unfair advantages" peps keep banging on about. ETNZ had already built their simulator and used it extensively for the BDA Challenge, so it made sense to ban two boat testing, in the AC36 Rule, no? I think there was some alluding to coast-saving as well, IIRC. ;-)

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21 minutes ago, Sailbydate said:

1Two boat testing is outmoded by technology and too expensive, when the Simulator provides a proven alternative. Perhaps it's another one of those "unfair advantages" peps keep banging on about. ETNZ had already built their simulator and used it extensively for the BDA Challenge, so it made sense to ban two boat testing, in the AC36 Rule, no? I think there was some alluding to coast-saving as well, IIRC. ;-)

I have to say that I disagree on how good simulator technology is in the real world. I’m more interested in F1 design than America’s cup. As you maybe aware most teams in F1 have their own wind tunnel or access to one. They all use CFD as well. The FIA has reduced the amount of wind tunnel usage a team can use. I think there’s limit on CFD as well but is no way  as limited as wind tunnel. The amount of wind tunnel usage is calculated by what place you end in the championship. The last place team gets the most and the winner gets the less amount. 
Ferrari got there CFD wrong this year. It’s there worst car for a long time. It’s even slower by 1 second than last years car. The rumor floating is they relied on CFD results and got it all wrong. Yet F1 must have the most sophisticated CFD in the world. 
moral of the story is CFD is not that good, tank testing is still better and more reliable. Pity it’s outlawed in America’s Cup

 interesting point F1 use flow-viz paint which shows how the flows around a car. It’s put on wet and evaporates where there’s more high speed flow of air against the surface of the car.  It leaves intrinsic patterns showing air flow. 

 

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2 minutes ago, mako23 said:

I have to say that I disagree on how good simulator technology is in the real world. I’m more interested in F1 design than America’s cup. As you maybe aware most teams in F1 have their own wind tunnel or access to one. They all use CFD as well. The FIA has reduced the amount of wind tunnel usage a team can use. I think there’s limit on CFD as well but is no way  as limited as wind tunnel. The amount of wind tunnel usage is calculated by what place you end in the championship. The last place team gets the most and the winner gets the less amount. 
Ferrari got there CFD wrong this year. It’s there worst car for a long time. It’s even slower by 1 second than last years car. The rumor floating is they relied on CFD results and got it all wrong. Yet F1 must have the most sophisticated CFD in the world. 
moral of the story is CFD is not that good, tank testing is still better and more reliable. Pity it’s outlawed in America’s Cup

ETNZ does not agree with you, Mako. Just as well eh, otherwise we'd be in deep shit. ;-)

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16 minutes ago, mako23 said:

I have to say that I disagree on how good simulator technology is in the real world. I’m more interested in F1 design than America’s cup. As you maybe aware most teams in F1 have their own wind tunnel or access to one. They all use CFD as well. The FIA has reduced the amount of wind tunnel usage a team can use. I think there’s limit on CFD as well but is no way  as limited as wind tunnel. The amount of wind tunnel usage is calculated by what place you end in the championship. The last place team gets the most and the winner gets the less amount. 
Ferrari got there CFD wrong this year. It’s there worst car for a long time. It’s even slower by 1 second than last years car. The rumor floating is they relied on CFD results and got it all wrong. Yet F1 must have the most sophisticated CFD in the world. 
moral of the story is CFD is not that good, tank testing is still better and more reliable. Pity it’s outlawed in America’s Cup

Sure, CFD is not a magic bullet. In the computer world there's a well known acronym: GIGO. Garbage In, Garbage Out.  As someone from ETNZ commented, they are constantly feeding data from their real life testing runs into the CFD program, and updating parameters etc. CFD is part science, and part voodoo. Make an incorrect assumption along the way, and the CFD program will turn out junk. So a lot depends on continuous updated data input, and how the computer boffins get the CFD to validate and interpret it. (IMO).

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10 minutes ago, Sailbydate said:

ETNZ does not agree with you, Mako. Just as well eh, otherwise we'd be in deep shit. ;-)

I think Team New Zealand is still using Numeca CFD software. They did use it in 2017 and I’m pretty sure there using it now. ETNZ do not have the resources to make their own CFD software. There’s nothing magic about what their  using. 

 

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10 minutes ago, MaxHugen said:

Sure, CFD is not a magic bullet. In the computer world there's a well known acronym: GIGO. Garbage In, Garbage Out.  As someone from ETNZ commented, they are constantly feeding data from their real life testing runs into the CFD program, and updating parameters etc. CFD is part science, and part voodoo. Make an incorrect assumption along the way, and the CFD program will turn out junk. So a lot depends on continuous updated data input, and how the computer boffins get the CFD to validate and interpret it. (IMO).

Totally agree, as someone who made a living looking after very large computers (Mainframe class systems) I can assure you that GIGO is so true 

 I also suspect the telemetry data from previous campaigns must  be a massive advantage. This must have data from as far back as 1992.  Talk about a validation tool ?

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16 minutes ago, Sailbydate said:

ETNZ does not agree with you, Mako. Just as well eh, otherwise we'd be in deep shit. ;-)

Hahaha... agree with you both!  ETNZ really nailed CFD in AC35, IMO, so they have a lot of expertise in this area. But... get it wrong, and it can be bloody awful. :(

PS: I used to design and write computer programs for major US construction projects. Did a lot of good stuff, but there were also some embarrassing cockups along the way! :D

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2 minutes ago, MaxHugen said:

Hahaha... agree with you both!  ETNZ really nailed CFD in AC35, IMO, so they have a lot of expertise in this area. But... get it wrong, and it can be bloody awful. :(

PS: I used to design and write computer programs for major US construction projects. Did a lot of good stuff, but there were also some embarrassing cockups along the way! :D

Same here use to write RPG on large as400 systems 

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26 minutes ago, MaxHugen said:

Hahaha... agree with you both!  ETNZ really nailed CFD in AC35, IMO, so they have a lot of expertise in this area. But... get it wrong, and it can be bloody awful. :(

That's exactly why you need to verify actual data against simulated data constantly to improve your CFD & simulation tools.

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29 minutes ago, MaxHugen said:

Hahaha... agree with you both!  ETNZ really nailed CFD in AC35, IMO, so they have a lot of expertise in this area. But... get it wrong, and it can be bloody awful. :(

PS: I used to design and write computer programs for major US construction projects. Did a lot of good stuff, but there were also some embarrassing cockups along the way! :D

I'm not saying ETNZ's simulator is any kind of magic bullet. I have zero understanding of the technology.

What I'm saying is that the validated simulator results thus far have given them enough confidence to eliminate the need for two-boat testing - which was the old school way of proving design innovation - and a very expensive validation process. The technology has overtaken that process, IMO.

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32 minutes ago, Sailbydate said:

I'm not saying ETNZ's simulator is any kind of magic bullet. I have zero understanding of the technology.

What I'm saying is that the validated simulator results thus far have given them enough confidence to eliminate the need for two-boat testing - which was the old school way of proving design innovation - and a very expensive validation process. The technology has overtaken that process, IMO.

Popeye I’m no expert in this area as well. I have a little understanding on how it works, but not enough knowledge to say anything definitive. To be honest I really don’t have enough info to give any opinion at all. I’ve just seen CFD go wrong with Ferrari and my own experiences with computers trying to simulate the real word. This includes Artificial Intelligence and Neural Networks trying to simulate the Stock Market. Needless to say I wasn’t successful. I doubt CFD can really simulate cavitation an area of critical concern to all syndicates.  


I’m not saying your wrong not at all you might be correct. only time will tell in the long run. I for myself have learnt the hard way that computer simulations can only go so far. However in  the field of computer simulation,  CFD is a lot better in its accuracy than a lot of other areas. 

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The teams that have the phrase "All models are wrong, but some are useful." on a large banner in the design office should be fine.

I would love to see the justification for Rita 1...:ph34r:

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1 hour ago, mako23 said:

I doubt CFD can really simulate cavitation an area of critical concern to all syndicates.

I've been haunting a CFD forum for more info on cavitation, as I have a concept for delaying it - which could of course be complete rubbish.

All I've found so far really, is that people are struggling with cavitation simulations. As you said.

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12 minutes ago, MaxHugen said:

I've been haunting a CFD forum for more info on cavitation, as I have a concept for delaying it - which could of course be complete rubbish.

All I've found so far really, is that people are struggling with cavitation simulations. As you said.

To simulate Cavitation you need to get into the area of Chaos mathematics.  I did try  reading and using Chaos mathematics for  Stock Markets  and all I achieved was pretty graphs and no useful results. Also a hurt brain because I’m no mathematical Wiz 

one of the famous edicts from chaos theory is the butterfly affect which basically state even the smallest difference in measurement for initial state will result in a completely different result at the end. This is why we can never predict the weather accurately no matter how much computer power you throw at it. Even if you increased the processing speed by a trillion fold.  I strongly suspect cavitation also fits into this chaos model as well. 

 

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27 minutes ago, MaxHugen said:

All I've found so far really, is that people are struggling with cavitation simulations. As you said.

One YouTube there’s a video of a young lad doing cavitation simulation with a wire hook with different attachment put into the water while he is  on a boat wizzing up and down a lake. It worked quite well, there might be your best bet. 
 

for small models there’s no need to do 50 knots in fact he achieved cavitation at 10 knots 

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10 hours ago, mako23 said:

This is why we can never predict the weather accurately no matter how much computer power you throw at it. Even if you increased the processing speed by a trillion fold.  I strongly suspect cavitation also fits into this chaos model as well. 

 

This is only partially true, and may be relevant to the problem in hand too. Sometimes the weather can be forecast well, and sometimes it cannot. And the models can increasingly tell the difference. If you run the weather simulation n different times with slightly different initial states then you will get. If those n results are all similar, then you have predictable weather. If the results come out widely different then you cannot. The number that are similar give an indication of the confidence you can have in your forecast. The more runs you can do, the better.

Fluid dynamics problems can sometimes be similar, or a little different in that the final state of the model on different iterations may be wildly different, but the average effect (in terms of frag or whatever parameters you are running) may actually be quite similar. This can be true for example of vortex shedding. Small differences in the initial state can make big differences to individual vortices, but the overall impact is quite similar.

 

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11 hours ago, mako23 said:

One YouTube there’s a video of a young lad doing cavitation simulation with a wire hook with different attachment put into the water while he is  on a boat wizzing up and down a lake. It worked quite well, there might be your best bet. 
 

for small models there’s no need to do 50 knots in fact he achieved cavitation at 10 knots 

I haven't found this video... do you have a link pls?

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16 hours ago, mako23 said:

I have to say that I disagree on how good simulator technology is in the real world. I’m more interested in F1 design than America’s cup. As you maybe aware most teams in F1 have their own wind tunnel or access to one. They all use CFD as well. The FIA has reduced the amount of wind tunnel usage a team can use. I think there’s limit on CFD as well but is no way  as limited as wind tunnel. The amount of wind tunnel usage is calculated by what place you end in the championship. The last place team gets the most and the winner gets the less amount. 
Ferrari got there CFD wrong this year. It’s there worst car for a long time. It’s even slower by 1 second than last years car. The rumor floating is they relied on CFD results and got it all wrong. Yet F1 must have the most sophisticated CFD in the world. 
moral of the story is CFD is not that good, tank testing is still better and more reliable. Pity it’s outlawed in America’s Cup

 interesting point F1 use flow-viz paint which shows how the flows around a car. It’s put on wet and evaporates where there’s more high speed flow of air against the surface of the car.  It leaves intrinsic patterns showing air flow. 

 

Ferrari is slow because they lost the engine advantage from 2019 that the car was designed around.  The car might be great with another 50 hp or whatever it is they lost due to the closed investigation and settlement that resulted in a much slower car.

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3 hours ago, Lost in Translation said:

Ferrari is slow because they lost the engine advantage from 2019 that the car was designed around.  The car might be great with another 50 hp or whatever it is they lost due to the closed investigation and settlement that resulted in a much slower car.

Ferrari was pinged with finding a way in tricking the fuel sensor that monitors  how much petrol can reach the engine. Since this trick has been fixed it does limit there top speed. It is believed that half way during last season they implemented the fuel sensor trick.

The car is slower than last years car before they engine flow trick was implemented.  Nor does it explain the lack of grip at the rear of the car. The car  becomes twitchy and sometimes the back end will completely go, This was not such a problem last year

Ferrari also supplies other teams with engines and has always maintained a gal between them in race pace. This Gap does not exist anymore. This gap existed before there engine flow sensor work around.


It’s no secret about Ferrari CFD failure 

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5 hours ago, enigmatically2 said:

This is only partially true, and may be relevant to the problem in hand too. Sometimes the weather can be forecast well, and sometimes it cannot. And the models can increasingly tell the difference. If you run the weather simulation n different times with slightly different initial states then you will get. If those n results are all similar, then you have predictable weather. If the results come out widely different then you cannot. The number that are similar give an indication of the confidence you can have in your forecast. The more runs you can do, the better.

Fluid dynamics problems can sometimes be similar, or a little different in that the final state of the model on different iterations may be wildly different, but the average effect (in terms of frag or whatever parameters you are running) may actually be quite similar. This can be true for example of vortex shedding. Small differences in the initial state can make big differences to individual vortices, but the overall impact is quite similar.

 

In the short term you can predict the weather. However the butterfly effect come in play for models that predict longer weather forecasts. So let me be more exact, no increase in computer power will increase the ability to predict long range weather. 
It’s not me saying this but Chaos mathematics 

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A recent video by Team Ineos is very instructive, for how much parallel compute-power teams are now using for CFD, down to remarkably detailed rig areas. In this fast-moving area, money and expertise for compute resources matters! It’s not 2016 any more. 

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4 hours ago, mako23 said:

In the short term you can predict the weather. However the butterfly effect come in play for models that predict longer weather forecasts. So let me be more exact, no increase in computer power will increase the ability to predict long range weather. 
It’s not me saying this but Chaos mathematics 

Aaarrgh!   Chaos Theory... tried looking at that... but way over my head.    Sort of: if you know the exact conditions at the start, you can predict the conditions at the end. The problem is, knowing the precise start conditions.

"Chaos: When the present determines the future, but the approximate present
does not approximately determine the future."
- E. Lorenz

I read somewhere that the "120 hour" rule - the time before a race that a team cannot make changes to their boat - was decided as being as far out that the weather bureau could reasonably predict the weather.

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1 hour ago, mako23 said:

Here you go  my Aussie Friend

https://www.youtube.com/watch?v=JYDKiWxLeos

Ha! I'd actually watched this, years ago... probably during the AC35!  Thanks mate.  It's interesting in that it demonstrates that  cavitation is the result of both speed AND form. :)   ETNZ's foils in AC35 apparently had a thinner profile which delayed the onset of cavitation... they made them from milled steel, and accepted the weight penalty for better performance.

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37 minutes ago, MaxHugen said:

Ha! I'd actually watched this, years ago... probably during the AC35!  Thanks mate.  It's interesting in that it demonstrates that  cavitation is the result of both speed AND form. :)   ETNZ's foils in AC35 apparently had a thinner profile which delayed the onset of cavitation... they made them from milled steel, and accepted the weight penalty for better performance.

I remember watching them in a video showing them making their keel using a special steel. This was for either NZL 32 or 38. It was a long time ago, but they were claiming they had a special technology in the process that gave them an advantage. 

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46 minutes ago, MaxHugen said:

Ha! I'd actually watched this, years ago... probably during the AC35!  Thanks mate.  It's interesting in that it demonstrates that  cavitation is the result of both speed AND form. :)   ETNZ's foils in AC35 apparently had a thinner profile which delayed the onset of cavitation... they made them from milled steel, and accepted the weight penalty for better performance.

That was after they broke the carbon ones...

 

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On 10/8/2020 at 4:00 PM, mako23 said:

Same here use to write RPG on large as400 systems 

My company was the first in NZ to develop a skills-matching GPS-powered despatch system matching suitable techos nearest to the type of fault requiring immediate response, running on Informix on AS400s, back in the late early 90's when the cost of data over 027 was criminally stratospheric!! Funnily enough, we went head-to-head with IBM for the solution as they had AS400s with our client - and they ended up owning Informix Software in early 00's..

Those were the days B)

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38 minutes ago, mako23 said:

I remember watching them in a video showing them making their keel using a special steel. This was for either NZL 32 or 38. It was a long time ago, but they were claiming they had a special technology in the process that gave them an advantage. 

Unobtainium?:P

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11 hours ago, mako23 said:

In the short term you can predict the weather. However the butterfly effect come in play for models that predict longer weather forecasts. So let me be more exact, no increase in computer power will increase the ability to predict long range weather. 
It’s not me saying this but Chaos mathematics 

Depends what you call long range. They used to think that more than 4 days was long range and unreliable, but the techniques I have mentioned have extended that. But if you are talking a month or two then yes. You might as well just use historical records

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