34th America's Cup: multihulls!

I'm also very dubious about the benefits of the airfoil acting to generate
lift or downforce given the speed of the vessel.



(Rest withdrawn. I thought we were discussing another feature completely.)

 

Hi Peter, check my post #2783, you'll se some relevant calcs there. The horizontal wings are not too small if you consider the moment (instead of the force, which is small) they can provide. The lever arm is around 10 meters.

But those boxy things, they do look too small indeed. A CFD analysis would be necessary, in order to establish what's going on there.

Cheees

 

34th AC

If you click on these pictures you can see the tufts on the vertical portions
of the "seats" inside and outside. Also notice in the right picture that the top of the box has a shape similar to the top of an airfoil.
pictures by Giles Martin-Raget

 

looks like a good place to sit and eat lunch

 

Well, there is one box sitting on each side behind the trailing edge of the sail, depending on what tack you are on. Coincidence?
I also suggested a stabilizing effect when the boat is foiling and someone brought up the fact that they aren't big enough and the boat not traveling fast enough for them to have any kind of effect. When foiling, the balance effect is precarious at best and any little change could bring disaster. If that is the case, then the performance of those boxes could be enough to lend a bit more stability. Like the tightrope walker using a balance bar for stability. Well not really. Anyway, just more conjecture into the pot.

 

How about they're trying to fool OTUSA? If you look at the ETNZ aft beam & it's entire kingpost super structure, it has been totally redesigned since Auchland's first sightings. Of course, redesigning is absolutely part of the competition, but if they wanted to make "your eye look away from the real change," you'd add some dumb boxes with telltales on all the surfaces.

As I've said before, "what do I know." Watch the left hand as the right is picking your pocket.

 

I have just been shown a photo of a ground affect aircraft. The single wing is very similar in the shape to the forward fairing on ETNZ. If ground effect is in play it will have a stabilising affect under heel. Nice aye?

 

34th America's Cup: multihulls! Reports Oracle may be Deducted 2 points or more

Sports News papers here are quoting that the international jury may deduct 2 points from ORACLE in the Americas Cup AC 72 races as a penalty for the AC extreme 45 fiasco, meaning ORACLE would have to win 11 races before ETNZ won 9 races to retain the cup.

I my opinion this would be totally unfair, unreasonable and unjustified as the AC 45s have nothing to do with winning the Americas cup. Oracle have all ready lost there points in the AC 45 series and title as punishment.

A better decision would be to ban ORACLE for 2 years in all AC extreme 45s class races.

That would be like penalising a country at the olympics in a yacht class for cheating and then penalising also all other yacht classes for that nation even if another class has already won a yacht gold medal for their nation and asking them to return their gold medal.

Protest loudly now against such a decision.

OC

 

"May" is not the synonim of "will".
So you can stay calm, those sport pages have to be filled with some text every day...

 

Those tack-ons are bizarre. Auditioning for the next Batman movie? I wonder if the fairing is so light that it flutters over its entire length when hit with buffeting from the wing. Could the ducts contain that and quiet the rest of the fairing surface?

Has anyone checked the included angle between the inboard face, the mast, and the outboard face? 4 degrees would suggest wake recovery. One face for upwind and the other for down wind. Actually, it wouldn't be four degrees because the both the AOA and the apparent wind would differ, so it should be a bit less than 4 degrees, I think. But how would one face overcome the drag of the other three? An angle larger than four degrees suggests an attempt to isolate the endwash from adjacent areas. But why a box and not a rounded shape? Just another guess getting tested, I suppose.

Rule-wise, would such a duct be treated differently than a foil?

 

34th AC

A great tragedy will unfold if TNZ wins the Cup according to Dalton-it will be pitifull and I hope it motivates Team USA to utterly defeat the Kiwi's:

from Scuttlebutt tonight:

Emirates Team New Zealand managing director Grant Dalton doesn’t mince words about this America’s Cup regatta. Once 72-foot the catamarans have finished sailing here, he said, “they’ll never see the light of day. They’re too expensive, too complicated.”
He says Russell Coutts, chief executive of Oracle Team USA, had “a fundamentally flawed” vision when he, with owner Larry Ellison’s blessing, picked AC72s as the regatta’s boat type.

“That’s only one piece of it,” Dalton said. “But he had the conviction to follow it through. We’ve all been picking up the pieces ever since.”

More of Dalton's trash talking here: http://www.sfgate.com/sports/article/Dalton-has-need-for-speed-and-respect-for-Cup-4776242.php

 

I'd have to disagree Doug, I don't see anything Grant Dalton has said as trashtalking. A process of consultation with potential challengers is a good way forward to decide what the America's Cup should be. He doesn't rule out multihulls either just says it's one of the options to consider.

 

Dalton also wants a residentcy rule clause.

Also stated if they won the cup they would change to sensible boats. Meaning I suppose MONO Hull.

 

Exaggerated words, Doug. You are again opening the pandora's box which you asked us to close.

All that he has said is that he would change the boat type. He did not say "no more foilers", just no more AC72.

They are too big and too expensive, you can't argue that. However, think about smaller foil-assisted cats, with soft sails, smaller SA/Disp. ratio and more rational stability-control system. That is viable and would certainly decrease costs, increase safety, increase the importance of the tactical component during the races and attract more teams to LV and AC. I believe that's the direction which could be followed, and I'm pretty sure you too would like it. Nowhere did I see that he said "I will reintroduce the monohulls" - just "I will trash the AC72 class boats".

Cheers

 

I think the spoilers are a super duper red herring. Everyones been looking at them for days. All the photos are of the rear of the boat so we should be looking at the front to see what they don't want us to see. Peter