34th America's Cup: multihulls!

? Nobody said that they had not the SAS-like mechanism right from the start...The question is why they had been losing so long. I think Barker addressed the same thing, and said that the TNZ guys were lucky US Oracle had left them so long with the false impression they would win...

I do not believe professionals who are paid to work for a company - do you ?

Are you threatening me ? If so, see you in court ! ! !

I had NOT said they were cheating, I said they have probably used a semi-automatic foil control system, and they are afraid ( I do not know why...) to accept it publically. If they wish to be fair and honest, here is the challenge : Let them show the boat and the mechanism to the public !
You are so biased and afraid of the truth, which you, erroneously, believe it might steal, somehow, some of the glory of the US win, you had not even read my posts ! I do not believe automatic mechanisms were illegal under the AC72 rules. I do not even know if they should have been, or not. I think that there should be better be a public debate about their use in the AC35.
I thought that we were allowed to speak freely here . Is freedom of speech abolished by any hidden AC rule ? Do you really believe that all people would be afraid of threads like the one you had just attempted ? If so, you had chosen the wrong person...
Judging from your reaction, I can see that there should be some fire near the smoke... The fans of US Oracle are evidently afraid of talking about the issue of the extend of the automatisms US Oracle had used, because they believe that would undermine the public image TSpeer is trying to sell, that it was not the US Oracle boat, but the US crew which was faster in their learning "curve", and all that had changed after the 11th race was just a product of accumulated knowledge...
Dear Doug, if you wish to impose silence to me, you can : Just delete anything I have written so far - you have my permission . Doing this, you will convince me about what I say - because I do not believe that the marketing department of Oracle will allow, ever, to anybody to have a look at the boat itself...
It is one thing to be a fan of one sporting team, and another thing to be an employee of one company - to whom am I talking here, I wonder ...

 

Response to Peter's last post:

In the system I described the board moves to the position set by the actuator. The feedback is the difference between the position the actuator is set to and the position of the valve control location which moves with the board. The valve opens when that difference is non-zero and the cylinder moves to drive the difference to zero. This behavior does not require a pressure relief valve to open. The trimmer sets the desired angle by setting the actuator position, and the system adjusts the board to the desired angle assuming sufficient hydraulic pressure is available. Once the desired position is set on the actuator, the trimmer does not have to do anything even if the board has not yet reached the desired position.

This is fundamentally difference than the trimmer controlling the valve handle directly, either moving it by hand or directly by solenoids or an actuator. In that case the trimmer has to hold the valve open until the board is at the desired position.

Why complicate the system with a pressure relief valve opening on a regular basis? Are you trying to get back to the idea that some sort of analog "hydraulic" computer was used to automatically control the board angle using the load on the board as an input?

A bang-bang system has feedback, but unlike some other control systems the response to the feedback is discontinuous rather than continuous. http://en.wikipedia.org/wiki/Bang–bang_control

 

I do not see what the trimmer "decides" in this sequence of events. The role of the trimmer you describe is secondary, at best, and "decorative', at worst...This is a semi-automatic mechanism, very different from a genuine direct power assisted foil-turning tiller or wheel.

Yes, it can well be some sort of analogue "computer" ...We do not know the details to be sure about it, and, as I said, there can be no theoretically defined distinction between a more automatic / almost "intelligent" complex automatic system and a less automatic, more "dumb" series of servos and relays...
You have pointed a difference that makes me suspicious, indeed...A push-in / pull-out button can not be used to trim a continuously changing thing, like the AoA of the foils. We would had wished to see a tiller or a wheel in this place !
There is an automatism involved here, no question about this...The stability of the Oracle boat was phenomenal, and I do not believe that the TNZ crew was so dumb, as TSpeer wishes to SELL to us, that they could not do the same thing, if both team had only a direct power-assisted foil-turning tiller or wheel.

I believe that, regarding this AC, the following has been more true than ever :

Personally, I believe that a better design is more difficult to be succesful, and so should be awarded more, than a better seamanship. If we had wished to decide who were the best sailors, we should had watched one-design classes...
I do not understand why the US Oracle fans are not PROUD of their better design, which offered them a more stable, faster boat ! Oracle is a high-tech company, why are they afraid to declare that they had a better technology than their opponents ? Do they believe that, doing this, they will sell fewer Oracle products ?

 

So in your opinion the reason for the actuator is to remove the trimmers requirement to hold the handle to change the trim angle? ie the actuator can have a micro switch on it so when you hit the switch it just drives to the preset position? How does the trimmer change it from 2degs to 5degs to 10degs as per my original analysis? Does it have multiple stops? I'll explain my interpretation once I understand yours. But yes using my interpretation you acheive an automatic trim angle proportional to the force applied to the foil. In your interpretation this is not possible. I looked up the spec for the actuator and it moves at 3inches per sec. As the throw of the valve is about 2mm the actuator can easily keep up with the board. So the board change velocity is a function of the pumping capacity. Peter

 

Since there is no significant energy stored in the hydraulic system, there is never enough pressure to immediately execute a commanded foil movement. Pushing the button to move the actuator merely leaves a new position setpoint for the grinders to reach. The "HYDRO!" commands heard on the boats are probably issued every time the button is pressed, telling the grinders to crank. The grinders will know when they are at the new setpoint by a sudden increase in resistance as the valve shuts off.

From the trimmer's viewpoint, it's a "fire and forget" system. No error-prone human communication feedback is needed.

PS.
Component X looks like a spring. This then merely converts the position command at the leadscrew actuator into a force command which the valve requires.

 

I doubt the foil has preset stops which the trimmer follows, except maybe for max/min stops and a few guide positions. With the L/V-foil system on these boats, a new foil position will make the foiling hull seek a new stable height above the water. If the trimmer sees that the hull is too low or too high, he moves the foil to correct it. The Decavitator HP boat had basically the same system. I moved the main foil angle of attack to keep the pontoons at a good height above the water. The initial AoA was set at maximum. As the boat went on the foil and accelerated, the AoA had to be gradually reduced to keep the boat from rising too high and ventilating the wing. Preset stops would not have worked here.

Because the grinders' cranking and the boat's altitude response all have significant lags, I suspect much of the learning curve for the trimmer was to anticipate required changes and issue the necessary AoA commands slightly before they are needed. Avoiding "pilot-induced-oscillations" from system lags also requires significant timing skills which must be learned.

 

Some of the technical details in this discussion go right over my head. But it's my impression that yes, you've been implying Oracle cheated somehow. You seem to feel they either broke the rules, or broke the spirit of the rules - i.e., bent them until we could hear them creaking and groaning.

I don't see where you've offered anything to back that up but suspicions, assumptions, and pure speculation.

 

My interpretation is the same.

 

I didn't find the exact specs for the actuator shown but for purposes of this description let's say the travel is 200 mm.

The actuator probably has a linear potentiometer attached and there is a readout of the actuator position at the trimmer's location.

Again for purposes of this discussion let's say the valve control moves 190 mm as the board moves from full forward to full aft rake.

The actuator and the valve control are linked by a spring

Here is how the system I described works:

The actuator and board are at the same position, say 67 mm, and the valve is closed.

The trimmer changes the actuator position to 108 mm and the spring pushes the valve control which causes the valve to open. The valve is fully open when the actuator gets to 69 mm, and the spring continues to compress which allows the actuator to move to 108 mm. The trimmer doesn't do anything additional and can now ignore the system.

The grinders grind and the board moves. When the valve gets to 106 mm the control valve starts to close and is fully closed when the board is at 108 mm. The grinders stop grinding.​

A very simple but effective system. The trimmer sets the desired board angle and the grinders grind without any attention from the trimmer.

As I mentioned earlier it also allows the trimmer to set the next board angle in advance and the board only moves to that angle when the grinders grind.

 

Hi David - What I don't get is how does the trimmer sets it to 108mm? There is no potentiometer described on the diagram? It just shows an electrical connection which implies a fwd,stop, aft button function. I'll have to digest Marks comments further and I agree that as there is no accumulator in the system the whole operation has to be choreographed. I also get that the board angle can be set in advance (due to the spring) which has to occur to shorthen the response time. But I think this is overcomplicating it, the position can be acheived using a mechanical gradicule, just need to ensure the grinders are grinding before you push the button. As the grinders are grinding nearly always during manuvours this is OK, but I'll think about it further. In short I agree with your explaination but I think it has further operational aspects. Cheers Peter S

 

I agree there is no potentiometer shown in the schematic. But that doesn't mean it's not there. The website for the actuators shows high accuracy potentiometers as part of the actuator. The potentiometer moves with the actuator but is not otherwise directly involved in the operation of the actuator (unless through an external control system). My assumption is the potentiometer would be connected to an instrument which would have read out actuator position.

To me the system shown is simple, though not as simple as direct control of the valve. Whether it is worth the slight added complication depends on how much value is placed on the ability of the trimmer to quickly set the next desired board angle and then move on to another task.

 

So the mechanical analogy is that you have a mechanical lever, like a sequential gearbox. The mechanical lever is like the height adjustment on a lawnmower. Say we have to adjust from 10degs to 2degs so we need 8 notches for 1deg or 16 notches for 0.5deg accuracy. This allows the operator to preselect the angle due to the compliancy of the spring, then the once pressure is applied it travels to that position. But we acheive this with a pot and use the internal displacment transducer to acheive this. This whole thing is done to free up the trimmer and allow anticipation of the movement vs trying to do it directly. OK I can see all of this happening, better get off to work now!! everything is simple in the end... now they just to have to adjust the relief pressure and it auto trims as well... Cheers Peter S

 

it is just plain bollocks what you write there.

The national flag is on both bows and what you are referring to is one of logo's of NZ Gov't departments in return for the $36 million dollars from the then Labour Government of the time. The red ensign is defaced on the red wing sail - does not have the correct color stars - not flying at the correct angle which flags do when there is wind and hue also obliged to the flags indicated position DOWN in cruial races and keep the NZ public stretch to their maximum sinking feeling. Barker is on record and stated that some thing was holding them down duing certain races. Some brand devil water splattered all over it which hue checked them for it. Total dissrespect for the national emblems that many country men have died fighting to preserve.The fern at mast head has also been defaced with the three last tip edges extended to represent NZ Now famous gold medal winning white and red wines including vintage wines winning major world recognition at almost evey national and international wine shows world wide by way of three wine glasses.

OC

 

HOTDOG!

I am missing all the mudslinging ....

I do know know if I can read all I missed.

Will someone tell me the highlights, so don't miss anything important?

 

Australia puts in a challenger for next americas cup

Have you heard Australia is the challenger in the next Americas cup. Wild oats owner and Hamilton Island Owner and vineyard owner.

What's he wines like - Have you tried any

Where is he going to get the aussie sailors from. Larry's got them all.

He is thinking about holding them - the next series in Hawaii. Near the island he owns.
OC