In a line-set, which element balances the load to allow smooth movement?

• A. Control line.
• B. Pulleys.
• C. Counterweights.
• D. Batten.

Answer: (C)

In fly systems, smooth movement comes from balancing the load with counterweights. The scenery and batten on the line-set have weight, and those weights are offset by counterweights on a weight arbor opposite them. When the weight on the counterweight side equals the load on the batten side, the net force is near zero, so the operator can raise, lower, or position the batten with minimal effort and very controlled motion. If you didn’t have this balance, the movement would be hard to control and could be jerky or unsafe. The other parts—control line, pulleys, and the batten—play important roles (you pull to move, pulleys guide the rope and reduce friction, and the batten is the bar that carries scenery), but it’s the counterweights that provide the balance that makes the motion smooth.