Virtual Skipper

[maitai]

Thanks Diades, that will prove helpful certainly. I am myself using eclipse plus an xml plugin for that.
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www.virtual-winds.com

[diades]

No problem, I have only tested it with the file provided in this thread so please shout if there are any problems. It may also be possible as time goes on to refine it with possible values that are acceptable so that less errors occur.
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Cheers,

Keith

Web Development help form WebXpertz

[Liese]

Hi all,
I do realize that this thread is quiet old...nevertheless I am starting from (almost) the bottom.

I have Polar Diagrams for the model I want to realize in VSK5.
These Polar data contain Velocity info for following wind strength
(kts) 6, 8, 10, 12, 14, 16, 20
and corresponding Heel data.

I will add my assumption about boat behaviour at 25, 30 and 35 kts.

But HOW DO I INTERPRETATE THE BSCoef data?

Here is my try:
Considering BSCoef(TWS) = f(AWA,OptimalSailAngle-CurSailAngle)

[kiwi_bardy]

Do you mind me asking what the boat is you are working on?

Just curious to see what is in the pipeline?

[admiral]

To lazy to look into the whole BS segment,

but basically there is a predicted velocity (1st curve)
TWS, TWA , Sailangle speed in Knots

aka a TWS and a TWA and a Sailangle give a Boatspeed

BS coeefficient as penalty for deviating from the optimal sail angle. (there are many other curves for BS coefficients aka heelingangle, rudderangle etc)

aka a TWS and a TWA and a deviation from the Sailangle given in 1st curve (above) give a speed factor where 1.00 = 100% and 0.00 = 0%


If you can not know how the boat sails: (Want to make VSK model of a sailing automobile)
Afaik research with "twisted airflow" wind tunnels, should have (be able to) provided some data from which "realistic" theoretical numbers can be predicted. There is some research going on in that area with windtunnels in New Zealend Auckland and i think in Germany Wilhelmshafen.


If you know the boats designer or an owner. (Want to make a VSK model of a real life sail boat)
Empirical data maybe available from any sailboat campaign which plots all data you need. (TWA, TWS, BS, Sail Angle.)

BTW AFAIK rudderangles are not plotted in real life sailing, rudderangle BS coefficients especially shortly applied rudderangles (eg. while turning) are very hard to distinct from other parameters like swell, hull movement etc. You could derive data from known aerodynamic profiles (wing shape) and given angle of attack. (nasa)

If you want your model to be realistic make sure you have smooth curves
with rather more data points then less.

Theoretical derived data from windtunnel models last time i looked was considered to have an accuracy of 25%. If your boatparams can beat that number (25% accuracy) you are a genious.

If you have read this far you should by now be impressed by the amount of work boatbuilders in vsk have put up with to make a vsk boat behave realistically. So make sure you go easy on them when asking updates, features, new models etc

[Liese]

I do not get your point
What is the intension of your answer after Line 6 ?
Up to line 6 - thanks for your help

I just want to create a boat model.
And I will estimate all relevant data from my experience as soon as I understand the structure of the Nadeo XML file.

Is it right, that the BScoef is not relevant if I sail in Automatic trim mode?
Or do I mix up some things?

Just seen Bardys question before
I will try to create a BALLAD - not much of interest for racers
(i.e. www.Ballad.de)

Best regards and thanks so far,
Joerg

PS: If anyone knows a 3DSMax guy , who can transform my Ballad from obj file to the required file format for the boatimporter- feel free to send me a PM or email (Liese at vskfun.com)

[Rich oot1960]

This will give you some insight on Polars:

http://www.vsk-aus.com/index.php?option=com_content&view=article&id=170&Itemid=212

This is a "Explaining XML file" of mine, it is NOT a working XML it is to help explain the in's and out's of an XML.

http://www.box.net/shared/t6nbym9k5o

Good Luck.

[admiral]

[kiwi_bardy]

[cotton]

There's many ways to use the function, this one has been choosen for nadeo's boat.
Feel free to choose another way.