34th America's Cup: multihulls!

34th AC

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Call me dense-I don't get your point? Thruout a lot of history foilers have been designed with around 80% of the weight on the main foil(s) at takeoff-increasing with increased pitch force from the rig.
Is that what you were getting at?

 

Doug I think he means the righting force must equal the tipping force. Durr.

 

34th AC

TNZ damages their wing while trying to rig: http://www.sail-world.com/USA/Americas-Cup:-Emirates-Team-NZ-damage-wingsail-in-launch-drama/107627

 

34th AC

Great Oracle video:
http://www.youtube.com/watch?feature=player_embedded&v=Y6dnOlE9sjk

 

VERY interesting..
Is it just me, or towards the end of the video, I see no rudder foils - the windward rudder has foils earlier on in the video (relatively small ones), but toward the end of the video I can't see these. This might substantiate Doug's earlier claims that they have a teenager with fighter-pilot reflexes and an overdose of sugar holding a joystick controlling the ride height. At some point it looks like only a few inches of any of the rudders are in the water, what on earth is steering the beast at this point ?
Looks like they are a much better sorted out team than they have shown in the past. I'll take back some of my doubts, though this footage is in moderate breeze, perhaps what they are expecting during the finals.
I'd still love to see them line up against all of the challengers, rather than only the LV cup winner.

 

34th AC

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He is not a teenager-an older , heavy guy who wears glasses and is never seen because he goes down into the pod before they go out, or something like that.
Comrad, the boat wouldn't foil w/o rudder foils-not a chance-unless they can move weight like the kid who did it with an A Class cat.
http://www.boatdesign.net/forums/multihulls/raphael-censier-flying-legal-class-cat-46435.html

 

Doug, that's what my reference to a teenager overdosed on sugar was about - without T-foils on the rudder, you'd need one to control the ride height !
Yet towards the end of the video, I cant' see the rudder foils and the windward rudder is clear of the water. Do I need glasses, or just another glass of wine ?

 

34th AC

More wine. The foils are there.... I saw nothing toward the end of the video that would cause me to think they weren't there. I just looked at the video again and never saw the windward foil clear toward the end ?
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Jeez, I just saw what you were talking about-there was no foil on the windward rudder!!! And the whole boat appears to have a more nose down attitude then previous video. They must be testing the foil on the port side. Good observation there ,Steve-glad you persisted or I would have missed that entirely. Thanks!
But its definitely on the boat at :26 and :51 in-I don't get it unless the angle it was videoed from caused it to "disappear". Definitely needs more info-it appears not to be there at 3:03 in..... If you look at it multiple times knowing that it's there you can see the water disturbance-I think.
Fooled me...
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More proof that the foil is there from a guy on SA:

click to enlarge:

 

Wondering if there is still enough flex to make the normal T rudder foil ... dangerous ... meaning that is maybe the reason for their usually uneven and floppy flight ... so they hacked the windward job off.
Definitely not there in the last sequences, "normal" high aspect ratio rudder instead.

 

Doug, I think it's possible not all the footage was filmed on the same day, meaning they could have used T-foils on one film shoot and not on the next. Or they purposely used a rudder without foils on the starboard hull to throw a bit of confusion at the opposition, who are surely watching this much more closely than we are. They have different daggerboards in each hull, perhaps the starboard hull foil was not a fully foiling design, so they could sail it without a rudder foil. Almost all the footage of them foiling, is of them doing it on one tack only. So this could be an exercise in misleading their opponents..

 

The foils are there, I can see them... I saw nothing that suggests they have removed the t foils on the rudders... The foiling looks better sorted now too. I think come race day, all the boats will be so close that the best race team will take the win.

 

Can any of the multihull specialists here make a guess at what the result would be of an AC72 sailing against an AC45 in an actual round the buoys race? That is, the faster boat against a more maneuverable and rugged one.

 

34th AC

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The big boat would likely win if the course was big enough to allow them to foil and probably anyway. On foils particularly, and off foils the big boats are pretty manouverable.

 

Agreed, defecation tossed to the waiting pigeons to stir them up. BUT, little do THEY know that the little that they know ... is very little ... and we ARE observant and a cunning bunch of turds, reading THEM like a book. Ha.
You need to check again, Groper, there is NO T on the windward foil in the last sequence of the video.

 

34th AC

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I thought the same thing, Gary-but those black and white photos show the effect of the foil. And if you stare at it long enough you'll see the foil. Have a drink first and it will be even clearer.....