The PCTOPT option permits the specification of the wheel drag force on the vehicle to be a percentage (%) of the weight on the wheel. This provides for a more straight forward procedure to apply drag to the wheels.
The above table in Cards 8,9, Example 2 can be created using the PCTOPT1 option as follows:
• You can set the PCTOPT1=1.0 (card 8, field 5) but also note that the program will check and for all inputs
≤ | 1.0 |. If true the program assumes the inputs are for % drag.
• To lock the RF wheel, set the % drag to -1.0. A drag force equal to the weight on the wheel will be applied.
• To add engine braking, with approximately 50% of the weight on the rear wheels, to produce 10% total vehicle drag you would need to apply a % drag of -.20/MU to each of the Rear wheels. Where MU is the coefficient of friction. So assuming a coefficient of friction of 0.70, the following would produce the desired results: