This data was gathered by putting an automotive torque wrench on the steering wheel nut. "Spokes" were translated to degrees of wheel turn and rudder angles. The data were used in sizing an hydraulic-electric autopilot actuator.
Wheel to Rudder Turn Ratio | 11 | |||||||||
Rudder Quadrant Degrees | 90 | |||||||||
Steering Wheel Diameter | 30 | |||||||||
Speed during test (knots) | 6 | |||||||||
Hull Speed Correction | 1.927469 | |||||||||
AT 6 KNOTS | AT HULL SPEED | |||||||||
6-Spoke Wheel Turns | Wheel Degrees | Rudder Angle in Degrees | Measured Wheel Torque in Ft-Lb | Rudder Post Torque Ft-Lb | 10" Tiller (pounds) | 7" Tiller (pounds) | Rudder Post Torque Ft-Lb | 10" Tiller (pounds) | 7" Tiller (pounds) | |
1 turn 2.25 spokes | 495 | 45.0 | 78 | 858 | 1030 | 1471 | 1654 | 1985 | 2835 | Factory Hard Over Limit |
1 turn 1.79 spokes | 468 | 42.5 | ||||||||
1 turn 1.33 spokes | 440 | 40.0 | ||||||||
1 turn 0.88 spokes | 413 | 37.5 | 50 | 550 | 660 | 943 | 1060 | 1272 | 1817 | New Hard Over Limit |
1 turn 0.42 spokes | 385 | 35.0 | ||||||||
5.96 spokes | 358 | 32.5 | ||||||||
5.5 spokes | 330 | 30.0 | 40 | 440 | 528 | 754 | 848 | 1018 | 1454 | |
5.04 spokes | 303 | 27.5 | ||||||||
4.58 spokes | 275 | 25.0 | ||||||||
4.13 spokes | 248 | 22.5 | ||||||||
3.67 spokes | 220 | 20.0 | 30 | 330 | 396 | 566 | 636 | 763 | 1090 | |
3.21 spokes | 193 | 17.5 | ||||||||
2.75 spokes | 165 | 15.0 | ||||||||
2.29 spokes | 138 | 12.5 | ||||||||
1.83 spokes | 110 | 10.0 | 10 | 110 | 132 | 189 | 212 | 254 | 363 | |
1.38 spokes | 83 | 7.5 | ||||||||
0.92 spokes | 55 | 5.0 | ||||||||
0.46 spokes | 28 | 2.5 | ||||||||
0 spokes | 0 | 0.0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
Last modified: February 18 2017 20:43