Sail winches. A winch mechanism will be required for any model where you will be sheeting in 600 square inches or more. A large model, while maneuvering and changing course, can put a heavy pulling load on the sail winch, plus innumerable shock loads when the sails yank on the sheets. There are two popular winch configurations and two types of drive mechanism. The drum or loop configuration trims the sail by winding the sheet or a loop about a drum mounted on the shaft of a gear motor. The swing-arm configuration is very popular. In this, the sheets from the sails are attached to a long arm mounted on the shaft of a gear motor. The swing-arm configuration is very popular. In this, the sheets from the sails are attached to a long arm mounted on the gear-motor; as the arm is rotated it either pulls in the sheets or releases them. The two drive mechanisms are the switch-operated gear-motor and the proportionally controlled or "proportional winch." The switch of the gear-motor is linked to the sail servo and the motor is turned on and off as well as reversed by the switch position. The position of the transmitter control is not related to the position of the sails. The proportional sail winch has electronics similar to those in a servo, which in effect turn the gear-motor into a very high-power servo. With the proportional winch, the position of the winch and the sails is proportional and directly related to the position of the control on the transmitter.
