34th America's Cup: multihulls!

I remember reading somewhere a claim by an ETNZ supporter that the ETNZ boat had a set of lights which showed whether the foil was at the desired angle, and the crew controlling the foil adjusted the foil angle until the lights showed the foil was at the desired angle.

 

Additional speculation about the system shown in the schematic.

With a valve added to each of the hydraulic lines going to the cylinder the cylinder could be locked in place by closing the manual valves. This would then allow for preselecting the foil angle prior to a maneuver. Procedure would be:
- Close the "locking" valves.
- Set the actuator corresponding to the next desired foil angle.
- Open the "locking" valves.
- Grinders operate the pump and the foil moves to the selected angle.

.

 

That could be one possible way to operate the system, by all we can see in the drawing of the circuit. The other way is full auto, based on sensor readings. It would imo still be legal, since the actuator serves only to guide the hydraulics, without providing a driving force (which is manual).
The hydraulic part is actually very simple, even trivial. The actuator part is the real unknown.

 

My guess is control of the actuator is manual by push buttons or similar as drawn.

A simpler system to control the hydraulic power would have the link the actuator directly to the control valve without "component x" in between. The movement of the foil would be controlled by the buttons with the work done by the hydraulics. Push one button with the pump operating and the "pivoting part" moves one way until the button is no longer pushed. Push the other button and the "pivoting part" moves the other way. My guess is that is what was envisioned for hydraulic system control when the rules were written.

By mounting the control valve on the "pivoting part" and the actuator on the fixed part (or the other way around) with a spring and dampner between them a bang-bang type of control of the "pivoting part" angle results. The push buttons go from controlling direction of movement to controlling desired position. Simple and effective.

Edit: Also obvious once someone draws it.

 

It appears that any external, automatic input into the valve control system was prohibited by the rules. Presumably the measurers checked this. The measurers explicitly ruled that the system shown in the schematic was legal as long as the spring in "component x" was sufficiently flexible.

From the AC72 class rules http://www.cupinfo.com/downloads/ac72-class-rule-1p1-a14-052413.pdf :

19. MANUAL POWER AND STORED ENERGY

19.1 Only manual power (the force exerted by crew) or the effect of direct contact with wind and/or water shall be used for the adjustment of rigging, wing, soft sails, rudders and daggerboards.

19.2 The use of stored energy and non-manual power is prohibited, except:

(a) for small springs, shockcord, and similar devices;

(b) low pressure hydraulic or gas accumulators of less than 6 bar which provide back pressure to a hydraulic system to prevent cavitation, but do no significant work themselves;

(c) batteries to power electric bilge pumps, provided the total capacity of all pumps is not greater than 200 l/min; and

(d) batteries to power instruments, on board crew communication and ACRM media equipment; and

(e) for electrical operation of

(i) hydraulic valves. These operations shall only provide the input for the position of the valve;

(ii) drive clutches in winch systems.

The valves and drive clutches referred to in (i) and (ii) above, shall be commercially available and Competitors shall have had these approved by the Measurement Committee for use via an issued interpretation.

The operation for (i) and (ii) above, shall not receive external input from any source other than manual input. Any data acquisition system, associated sensors or electronics shall be physically separate and completely isolated from any electrical operation referred to in (i) and (ii) with the exception of the voltage supply. The manual input may latch the valve(s) or clutch(es), operate multiple valves or clutches, and /or provide variable position. Valves and clutches may be operated from multiple manual inputs.

These systems may be hard wired directly between the manual inputs and shall be hard wired between the manual inputs and the valve(s) or clutch(es). Wiring shall be clearly identifiable. Electrical energy used for this shall only be stored in batteries, including small capacitors.​

 

First Foiling America's Cup

From Tom Speer posted by Lohring Miller on another forum:

The boats are experiencing cavitation, so they may hit a wall soon that will limit their top speeds. But I'm sure there is still lots of performance to get out of them! We had to repaint the rudders every night because of cavitation damage.

There is no SAS. There were no gyroscopes or electronic feedback sensors. The measurers were fully informed during the development of our system and certified that it complied with the Design Rule. There was even a Public Interpretation issued that dealt with our design. We got more stable because we learned to fly our boat better. Just like ETNZ got more stable as they gained time on the water.

Cheers,Tom Speer

 

Yes, the drawing does not show the "chart" which has to be blindly followed by the puppet-sailor / "trimmer", and which incorporates the knowledge collected during testing...( I follow the scenario of the previous posts here ). There is no "decision" worth the name, there is only a not-intelligent pushing of a button, according to a simple pre-determined procedure. WHO really believes that the operator of this mechanism has to be an intelligent, or even a thinking person, like the helmsman of the boat ? This semi-automatic mechanism, where the human operator plays an easy, almost passive, and secondary role only, could be easily developed into a fully automatic system, if the rules of the next cup would allow it.
Of course people will jump and shout : It is no SAS, it uses no "stored energy', it is not automatic. However, it does stabilize the boat by adjusting the AoA, it does use energy AND information ( in the form of the input by the foil, and the "target", determined during testings, which has to be followed blindly ), it is automatic - otherwise it would have not be used in the first place. Does anybody in this forum really believe that this system does the same job as a foil-turning wheel steered by a "foil helmsman" ? If that is so, what is the name of this super-human trimmer who can trim the foil so accurately and quickly, possibly more than one times each second, to eliminate any pitching ? He should have played MANY computer games in his youth...

 

Translation : We became more stable, because we are more clever, and learn faster. They were more stable, because they were just lucky, and had the chance to spend more time on the water.

I wonder, why people can not whisper, at least, the obvious : We got more stable, because we had a cleverly designed boat. I guess it is because the marketing department had "advised" them otherwise...
To everybody who watched the event, it was evident that the miraculous transformation, from feather duster to rooster , of the US Oracle boat was not gradual, as a learning curve always is. They had not learned something they did not know already, they did something they were not doing ! The transformation from a frog to a prince was sudden, and this tells me that it was the outcome of one crucial decision regarding the set-up of the boat, which was proved to be the right one, and which they should have taken earlier...

 

This last phrase is in contradiction with the first part of what you wrote. It assumes that this system serves to elliminate "any pitching" - but that's something you don't really know. It would then be an SAS, which TSpeer says is not installed on board, and I believe him. Such a system would necessarily have to be fully automated, because it would have to make continuous changes to the foil angle, coordinated with an equivalent action on the wing. It would physically exhaust the crew after very short time, because it would require a continuous grinding.

A more plausible purpose of this system, imo, is the one described (in various versions) in the last couple of posts. The helmsman gets a visual suggestion about the ideal foil/wing position for the current running conditions of the boat, and uses this actuator-assisted adjustment system to set the foil/wing at this suggested optimum angle. It doesn't require a high-frequency actuation, 3-4 adjustments every minute would be sufficient, to match the changes of the average wind and boat speed.
Where do the suggested values of optimum values come from, that's the crux of the story. They might as well come from the skipper's head, based on experience from the countless hours of training and refining the boat.

 

First foiling AC

This was taken by a guy who was there and it is "the moment when....":
http://vimeo.com/75364288#at=0

 

Oh, this is the only thing I do know - I have watched the US Oracle boat, and I have not noticed any pitching, like what I did in the previous 11 races ! TSpeer, of US Oracle team, has tried to persuade you that this was the outcome of a learning curve that suddenly has been flattened out... - and it seems that he has succeeded in this !
One can make a small number of minor alterations to an existing system, and then he can call it with whatever "legal" name he wishes... ( "power steering" system for moving the foils (sic) was a good try... ). The systems described in a number of previous posts may not be identical to the existing SAS systems of airplanes ( they are probably much simpler ), but their function remains the same : they control the AoA of the foils in a much more accurate and quick way than ANY human could achieve - even if he was playing video games 24 hour per day from the first day he was born.
What is a not-automatic rudder ? A mechanism that controls the AoA of the foil of the rudder, by the power of the muscles of the helmsman s hand, multiplied through a "simple machine", be it a level/tiller or a wheel on an axle. We see the helmsman pulling or pushing the tiller or turning the wheel, and we know that the rudder itself turns accordingly, at the same time.
What would have been a not-automatic foil-steering mechanism ? A mechanism that would control the AoA of the foils, also by the power of the hands of a human, a trimmer, also multiplied, this time through the added power of the muscles of the hands of the grinders. We would have seen the trimmer pulling or pushing the proper foil-steering-tiller or turning the foil-steering wheel, and we would have known that the foils themselves turn accordingly, at the same time.
Is that what we have seen ? Is that what the supposedly not-automatic and supposedly not-SAS system the US Oracle boat was equipped with ? And if that was the case, what was the purpose of all those paraphernalia shown in the published drawing ? Decorative ?
No, I believe we can say that the role of the "trimmer" ( = push-button operator ) himself, in the workings of this system, was - regarding the "decisions" he should take - decorative... Otherwise HE should have been considered the rooster, and Spithil should had remained the feather duster...

 

First Foiling AC

--------------------
The videos I posted here the other day show Oracle pitching less than TNZ and going faster before the Cup had even started. What was sudden was when they started winning. post 3740 Published on the 17th and 18th of August.
=========
Xarax, you are dangerously close to impugning the character of Tom Speer and many other good and decent people and that is unacceptable. Be very, very careful in your implications of Oracle cheating using baseless supposition and zero facts. That kind of thing will not be tolerated(by me- and others, I imagine) because it is just plain unfair, uninformed and wrong.

 

Sas

Hi - I've been looking at this diagram and it creates a few questions rather than answers. eg 1) The Hawe valve is a 4/3 type which means it has 4 ports and 3 positions. Its positions functions are fwd/stop/aft movement of the daggerboard casing. 2) Its mounted on the casing which means as the board moves it moves, this is unusual 3) Usually this type of valve is directly operated by a handle. So it could live where the trimmer sits. By pushing the handle fwd the daggerboard would rotate forward, by letting go of the handle it would stop and by pulling back on the handle the board would move backward. Very simple used on most hydraulic machinery. As the board trimmer and the board are close together why have they decided to use an electric actuator to move the valve? (because as most people are saying here we don't believe that a person can trim this system fast enough to be effective) This would be slow and have odd spots as the spool moved over its grooves. Plus if it were to operate in the normal manner they would have used solenoids to flick the spool not an actuator? 3) As the valve moves with the casing and the actuator is nailed to the structure, a compliant connection between the two has to be used. This is a spring in the drawing. 3) Whats not shown is a pressure relief circuit, it must have one 4) so the following happens: if the relief is set at the "correct" pressure (and I think this would be one of the controls the trimmer had), when the force on the board is big enough the relief allows the board to move (as normally its hydraulically locked out) this moves the valve, which hits its stops turning it to fwd or aft as required which moves the board slightly, result... trimming it. The actuator is used to do gross trimming but for small trimming the board does it by itself!! Very smart!! Heres your answer lads!! Its a sort of self centering effect drive the board to the "correct" angle then use the relief to change the sensitivity ... Peter

 

Agree.

Mounting the valve and the actuator so that they move relative to each other when the board is moved is the key to how the system functions.

Why does the person who trims the board have to sit next to the board? It is not required by the rules. The could be a number of advantages to having the person who trims the board located elsewhere. I saw reports when the Oracle boat was first seen that the board angle was controlled from the helm.

The use of a linear actuator rather than simple solenoids is another key to functioning of the system.

My interpretation is the device between the actuator and valve is does more than provide simple compliance.

My interpretation is the total linear travel of the actuator is greater than the total linear travel of the valve body over the range of board angle change.

The linear travel of the actuator and valve body is much greater than the amount of linear travel relative to the valve body of the control handle where component X is attached.

Component X is a simple mechanical device which allows the valve body to move relative to the actuator a greater amount than the control handle can move. When the valve body moves forward of the position of the actuator the control handle is pulled back which in turn causes the cylinder rod to move rearward. When the valve body moves rearward of the position of the actuator the control handle is pulled back which in turn causes the cylinder rod to move forward. When the actuator position and control handle are aligned the cylinder is locked.

The result is a simple bang-bang control system. Move the linear actuator to a new position and the board follows to that position.

Yes.

You have arrived at almost the same interpretation which I did and posted yesterday in post #3755. Why would the pressure relief valve be set lower than the safe working pressure of the system? If the pressure relief valve opens and the board moves, then the system will just try to drive the board back to the preset position.

Reminder - my comments are based on speculation about publically available information such as the schematic and may be completely erroneous.

 

David - your interpreation can be simplified to "move the actuator the case moves". My point is that this can be acheived by using a handle on the valve so why use the actuator? But this means the trimmer has to move the casing nearly continuously to load match the foils lift and attitude. My interpretation includes using the relief to establish a loop between the cases position and the valve, which means the trimmer does not have to do anything once the gross angle of the case is set. If the relief is set to allow the board to move at a given load that movement opens/closes the valve which trims the board. This is not how you describe it. A bang bang system is has no feedback loop in it, it just is fwd, closed, aft. Hope this helps. Oh yes the trimmer does not need to be near the foil thats just how they have it arranged on a AC72.

The relief is not being used to set the safe working pressure. There maybe a system pressure relief but in this case the "relief" is used to establish a control loop between the valve and the board, which is independant of the operator (or automatic as some say) . Peter