My aero has only been fitted for starboard tack. What should be changed to the aero in order to model manoeuvers with the boat?
If the aero has only been fitted for starboard tack, then it will extrapolate to garbage values on the port tack. One solution is to build the mirror image of the data, i.e. to duplicate the points in excel for the mirror solution on port tack (eg. create the AWA < 0 cases). Be sure to follow the rules below:
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- The following should be negative for the mirror image:
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- AWA10
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- Heel
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- Sway (Fy)
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- Roll (Mx)
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- Yaw (Mz)
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- The following should be negative for the mirror image:
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- The following should not change sign:
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- Travel, TwistM, TwistJ
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- Surge (Fx)
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- Heave (Fz)
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- Pitch (My)
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- The following should not change sign:
Whether other aero parameters (e.g. Travel and Twist) should change sign is in fact debatable and will depend on the definition of those parameters in the aero data.Note that if using the built-in ‘Sail’ block to model dynamic sail graphics, then all the sail trimming parameters will have to be updated so that they swap sign depending on the tack side.