Luna Rossa Challenge. AC 36

[JALhazmat]

So they are resigned to having to use one on each tack under tension but want to hide the slack one in the little fairing, when they tension it it pulls free.

either this is a huge distraction fir something else or they are thinking it’s vital to boat performance and they are desperate to remove/hide the back stays. 

 

[SeanPurdy]

Picking up on the feathery theme from upthread, I saw this post on gust response in birds' wings on the brilliant blog Fuck Yeah, Fluid Dynamics:
 
"In flight, birds must adjust quickly to wind gusts or risk crashing. Research shows that the structure of birds’ wings enables them to respond faster than their brains can. The wings essentially act like a suspension system, with the shoulder joint allowing them to lift rapidly in response to vertical gusts. This motion keeps the bird’s head and torso steady, so they can focus on more complex tasks like landing, obstacle avoidance, and prey capture." 
 
I have absolutely no idea how you would engineer something like this into an AC75 rig, but it might have helped American Magic in that bearaway.

 

[MaxHugen]

Picking up on the feathery theme from upthread, I saw this post on gust response in birds' wings on the brilliant blog Fuck Yeah, Fluid Dynamics:
 
"In flight, birds must adjust quickly to wind gusts or risk crashing. Research shows that the structure of birds’ wings enables them to respond faster than their brains can. The wings essentially act like a suspension system, with the shoulder joint allowing them to lift rapidly in response to vertical gusts. This motion keeps the bird’s head and torso steady, so they can focus on more complex tasks like landing, obstacle avoidance, and prey capture." 
 
I have absolutely no idea how you would engineer something like this into an AC75 rig, but it might have helped American Magic in that bearaway.

Damn clever, those seagulls!

I also read that birds use their wing tip feathers to counter yaw, which is why they aren't born with a vertical stabiliser.

 

[enigmatically2]

So they are resigned to having to use one on each tack under tension but want to hide the slack one in the little fairing, when they tension it it pulls free.

either this is a huge distraction fir something else or they are thinking it’s vital to boat performance and they are desperate to remove/hide the back stays. 

I don't think they are resigned to using one on each tack. They have to be designed so that they could be tightened into use. Hence their comment in that interpretation reuest that if it were in the fairing, and they tightened it, it would come out and go tight. But I think they are without any intention of doing so because getting it back in would be very difficult

 

[JALhazmat]

I don't think they are resigned to using one on each tack. They have to be designed so that they could be tightened into use. Hence their comment in that interpretation reuest that if it were in the fairing, and they tightened it, it would come out and go tight. But I think they are without any intention of doing so because getting it back in would be very difficult

Which they aren’t allowed to do as it would be a fairing.. 

so thankfully we get more Italian tantrums  :lol:

 

[Zaal]

New foils ? Looks pretty the same to me in this NZSP video 

Here a screen : 

 

[Mozzy Sails]

Which they aren’t allowed to do as it would be a fairing.. 

so thankfully we get more Italian tantrums  :lol:

So, they can put the fairings on the mast, but as soon as they put the backstays behind them, they also becomes backstay fairings (despite not being attached to the backstay). 

I read it as back to square one for the Italians... I hope they're not dedicating too much time to this, as I feel it's a lost cause. Sure, have the coffee boy submit interp requests as a distraction for other teams, but I hope the real design team have refocussed elsewhere. 

 

[MastaVonBlasta]

This guy is a master spy - invisible to Luna Rossa fellas around him, visible only to the camera.

Just standing about, taking pics of foils.

Any images of the foil on the starboard side?

 

[JALhazmat]

So, they can put the fairings on the mast, but as soon as they put the backstays behind them, they also becomes backstay fairings (despite not being attached to the backstay). 

I read it as back to square one for the Italians... I hope they're not dedicating too much time to this, as I feel it's a lost cause. Sure, have the coffee boy submit interp requests as a distraction for other teams, but I hope the real design team have refocussed elsewhere. 

I agree, 

given the multiple attempts though I think they are betting big on this and now finding out that they are having the door repeatedly closed. i th9nk it started off as not a big deal, certainly max when asked in a presser (during xmas cup?) I think he kinda shrugged but with the increasing requests I think it carries more weight than he wanted to let on, almost certainly one of the reasons they protested Britania for the hole that wasn't a hole.

 

[enigmatically2]

Question is why though

1) Drag reduction? Well yes, but they are investing a lot of effort in this, more than would seem warranted, and if they do succeed, others will copy it easily

2) They have a problem with the runner ease and doing away with them or hiding them would cure it? I haven't seen any evidence of that on LR

3) It takes up crew resource during tacks and gybes and they want that person doing something else?

Any other ideas?

 

[JALhazmat]

drag, 

sail set up? if the sails have been cut to be tuned and work with a set up that has no runner tension I guess it would be sub optimal to have to tune them differently  in terms of shaping and twist.

if the under deck boom is giving them the leverage to do what they need then why have the runners, if they were using the runners then the under deck set up is carting around a lot of stuff that isn't needed + extra weight and systems

 

[Zaal]

https://docs.google.com/a/acofficials.org/viewer?a=v&pid=sites&srcid=YWNvZmZpY2lhbHMub3JnfGFjMzYtb2ZmaWNpYWwtbm90aWNlYm9hcmR8Z3g6NDUzOGE0N2E1OGM4NWNjYg

What about this one ? I honestly didn't understand a lot 

 

[alphafb552]

Could also be that the rear corners of the stern are structurally not built to support runner loads, so if their rig does not need them, and their structure does not even allow them to be used in the normal way, it's perfectly logical to try to find ways to hide them away aerodynamically

 

[enigmatically2]

Could also be that the rear corners of the stern are structurally not built to support runner loads, so if their rig does not need them, and their structure does not even allow them to be used in the normal way, it's perfectly logical to try to find ways to hide them away aerodynamically

If this or other design aspect, then why did they not ask the interpretations before they had built boat 2 and were committed to what is now looking a little like a blind alley

 

[buckdouger]

New foils ? Looks pretty the same to me in this NZSP video 

Agreed, they look similar. This guy was pretty interested though:

 

[alphafb552]

If this or other design aspect, then why did they not ask the interpretations before they had built boat 2 and were committed to what is now looking a little like a blind alley

Wouldn't be the first time a team got blindsided by seemingly obvious rules...

 

[MaxHugen]

Question is why though

1) Drag reduction? Well yes, but they are investing a lot of effort in this, more than would seem warranted, and if they do succeed, others will copy it easily

2) They have a problem with the runner ease and doing away with them or hiding them would cure it? I haven't seen any evidence of that on LR

3) It takes up crew resource during tacks and gybes and they want that person doing something else?

Any other ideas?

4) Mast bend flattens the camber up high too much. 

 

[JALhazmat]

https://docs.google.com/a/acofficials.org/viewer?a=v&pid=sites&srcid=YWNvZmZpY2lhbHMub3JnfGFjMzYtb2ZmaWNpYWwtbm90aWNlYm9hcmR8Z3g6NDUzOGE0N2E1OGM4NWNjYg

What about this one ? I honestly didn't understand a lot 

i thinkk it basically is saying, you don't have to have the runnig back stays attached while racing which is what Prada want 

the issue though is that if they are not attached what Prada do with them? they cant hide them in pockets, in-between the sail skins of down either side of the mast as that has already been ruled against.

also the attachments to the mast and the back corner must still be present and the system be capable of being connected to comply with the sail plan and supplied rigging directives.

so while theoretically you don't have to have them attached during racing configuration there isn't (at the moment) a way around the rest of the requirements?

 

[JALhazmat]

Agreed, they look similar. This guy was pretty interested though:

View attachment 422573

think he is looking at the other foil ?

 

[alphafb552]

They could lead them to the sides of the boat behind the main stays?

At least they'd be in already disturbed air