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Rudder box with gears

By Dermot Tynan, almost 8 years ago.

This photograph is of the new rudder box with a NEMA17 stepper (underneath) and the two gears. The smaller gear is on the stepper and the larger, quarter gear will be clamped to the rudder shaft. It's a 4:1 ratio and the rudder gear is 90 degrees so one complete turn of the stepper will bring the rudder from end to end. That's plus or minus 100 steps.

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The new rudder

By Dermot Tynan, almost 8 years ago.

Thanks go to Colman Corrigan for designing and building the keel and rudder. The keel follows the traditional NACA shape, with a rounded leading-edge, tapering off to a narrow trailing edge. It is approximately a 6318 shape, with the maximum width being about 36% of the length of the cross-section. Overall, the keel is coming in at about 750mm from hull to the end of the bulb, and about 240mm from front to back. That's a 3:1 aspect ratio.