America’s Cup - ETNZ launches 1st AC75 (new)

[jmh2002]

Originally Posted by wingssail

Further, they have now changed the rule to restrict the allowed modification to the hull, (preventing addition of a bustle to the existing hulls?) Humm

If my understanding is correct, this rule change, like all of the rule changes, has been discussed and agreed by all the Teams.

In fact I expect that this change was driven by the other Teams who very much understand that their window for any design, development, and changes is very limited and they want to mitigate this somehow.

TNZ, like all defenders, have a head start with all things design related. It's the historical status quo and is meant to balance against the fact that the defender can face multiple challengers.

[MicHughV]

"TNZ, like all defenders, have a head start with all things design related. It's the historical status quo and is meant to balance against the fact that the defender can face multiple challengers."

Correct me if I'm wrong here, like you always do, but the defender typically only faces one challenger. The challengers have to duke it out amongst themselves for the right to the " challenging" boat...yes/no?

[a64pilot]

Deflection as it’s been called has been dismissed by many aeronautical Engineers for ever, but they were wrong, or said another way of course lift from it exists and is easy to demonstrate, a kite flies doesn’t it?

In fact and this is kind of funny, but if you measure the differential pressure above and below a wing and multiply that by the amount of wind surface area, you’ll discover that there isn’t enough lift from that alone to fly.
There is more going on that just the simple wing gets sucked up by low pressure explanation.
https://howthingsfly.si.edu/aerodyna...-theories-lift

[Pelagic]

Originally Posted by a64pilot

In fact and this is kind of funny, but if you measure the differential pressure above and below a wing and multiply that by the amount of wind surface area, you’ll discover that there isn’t enough lift from that alone to fly.
There is more going on that just the simple wing gets sucked up by low pressure explanation.
https://howthingsfly.si.edu/aerodyna...-theories-lift

Don't tell me that....I'm already scared of flying![emoji120]

[MicHughV]

...I've always gone along with the theory that a bumblebee should physically not be able to fly given it's small wingspan and large body...

Bumblebee Flight Does Not Violate the Laws of Physics

But, in fact, as everybody knows, they can fly...and fly quite well...see above link...just not in the way we think they should...

Maybe A64Pilot can shed some more light on this phenonima.....because quite frankly, it is a bit of a mystery to me.

It's kinda like " gravity"....we can't see it, and whether we believe in gravity or not...it's there...

ok, a bit off topic....but what the hell.....guilty of one charge, might as well be guilty of two..

[Pelagic]

I have an unfortunate feeling we are going to see some of these AC sailors flying thru the air

[Jim Cate]

Originally Posted by Pelagic

I have an unfortunate feeling we are going to see some of these AC sailors flying thru the air

Just like a bumblebee??

Jim

[a64pilot]

I’m not sure what dynamic stall has to do with it, but I believe a Bee can fly mostly due to the effects of the square cube ratio, that is that things don’t scale like we think they should.
Many insects can walk on water, but larger animals can’t, full grown Lions can’t climb trees, and elephants can’t jump etc. , etc.

However as far as I know a bee’s wing isn’t really an airfoil, it’s a flat plate.
And contrary to much of what you read a flat plate can indeed fly, just not as efficiently as an airfoil. Look at a paper airplane, or a cheap balsa airplane that we all flew as kids, there is no airfoil.
Heck even most all feathering props are just flat plates, and yet they drive a boat, just not as efficiently as an airfoil.
There is no airfoil section to my keel, and yet it provides lift

[David M]

A hand out a car window can provide lift.

[Pelagic]

So can this
[emoji106]

[wingssail]

Originally Posted by MicHughV

"TNZ, like all defenders, have a head start with all things design related. It's the historical status quo and is meant to balance against the fact that the defender can face multiple challengers."

Correct me if I'm wrong here, like you always do, but the defender typically only faces one challenger. The challengers have to duke it out amongst themselves for the right to the " challenging" boat...yes/no?

This has actually evolved to a point differently from where it started.

For many years (about 166 years) the challengers, if there were more than one, determined how they would choose their yacht, often through a challenger series. The defenders, too, often had a series to determine which yacht would actually defend (often there were several contenders.) The defending yacht club allowed the contenders to race each other in order to obtain the best one for the defense. None of this is described in the Deed of Gift. In recent years the defender has ruled out a defender series thereby ensuring that no one else could usurp their right to defend the cup.

So, for a long time there was just about equal opportunities for defender and challenger to face opponents before the actual match.

The concept that this somehow gave advantage to the challengers really gained credence when NZ defended and there were no other defenders for them to face. (Poor Kiwis' they could only watch.)

New Zealand overcame that, as other defenders had previously, by building two or more yachts of their own so they could race against each other (one time Dennis Conner built four!)

Now, to supposedly reduce costs, two-boat competition or testing by teams is outlawed, and none of the competitors are allowed to sail against any other boat prior to the organized regattas. (However, as an equalizer, the defender, Team New Zealand IS allowed to conduct two-boat testing once the Challenger Selection Series starts.) Whew!

HOWEVER, with this cup there will be plenty of opportunity for the defender and the challengers to face opponents since there are going to be a series of “Preliminary Regattas” in which all competitors participate and will have a chance to take a measure of the opposition. The Challenger Selection Series however is for challengers only; the defender can only watch.

How did the meme of "The defender gets a head start in the design process..." come about? The deed of gift already slants the competition towards the defender. It makes the challenger announce which boat they will challenge with and then allows the defender to figure out how to beat that boat by designing and building a response. That's how come Dennis Conner was able to sail a catamaran against a monohull in 1988.

But in all cases the challenger and the defender could, and can, cooperate and come up with an agreed upon boat design. Then there is no advantage. That's what they are doing this time. It is hard to show that Team New Zealand has any design advantage over Luna Rossa Challenge, the challenger, since the two teams developed the AC75 rule together.

Now, for the other challengers, it's a different matter.

[MicHughV]

I'm not 166 years old....

but...in my memory it has always been the Louis Vutton Races that selected a " challenger"

Louis Vuitton Cup - Wikipedia

https://en.wikipedia.org › wiki › Louis_Vuitton_Cup

[tp12]

Originally Posted by MicHughV

I'm not 166 years old....

but...in my memory it has always been the Louis Vutton Races that selected a " challenger"

Louis Vuitton Cup - Wikipedia

https://en.wikipedia.org › wiki › Louis_Vuitton_Cup

If you follow your link you can see that the Challenger's Cup has been around since 1983 so is a relatively recent change.

[MicHughV]

yes, 1983 is almost 40 years ago.....give or take a year or so....so not sure that a "relative recent" change is an apt description...though taken in context with the entire history of the AC it probably is. Most crew members on the AC boats were likely born during this 40 year span, so it's possible that this is all they know.

I launched my first boat in the early 80's....so this is when my experience with the AC started.

But the past history is besides the point in the current version of the AC where there will be a challenger series to determine who finally goes up against the Kiwi's.

I have heard rumors that LV sponsor has been unhappy with with a number of things recently and and this challenger series is now the Prada Cup...

The AC has more twist and turns and sub-plots than any good detective novel story...I can't keep up anymore....

[wingssail]

Originally Posted by MicHughV

I'm not 166 years old....

but...in my memory it has always been the Louis Vutton Races that selected a " challenger"

Louis Vuitton Cup - Wikipedia

https://en.wikipedia.org › wiki › Louis_Vuitton_Cup

It's a recent thing. Maybe you think 40 years is a long time.

BUT, before the "Challenger Series" the challenging yacht club did choose a challenger from among candidates. The challengers had a run off. AND the NYC (for that was who it was) had an elimination series to determine who would defend.

The point being, both the challengers and the defenders had opportunities to test their yachts against other yachts.

They still do.