What is the role of a "control line" in fabric covering?

The role of a "control line" in fabric covering is primarily to maintain tension and ensure the integrity of the fabric on the aircraft. Control lines are critical for preventing fabric sagging and distorting, which can affect aerodynamics and the overall performance of the aircraft. Proper tension helps to maintain a smooth surface and can also contribute to the durability of the fabric, thereby enhancing its resistance to environmental conditions and wear over time.

By controlling fabric tension, these lines play a vital part in the overall structural integrity of the aircraft's covering system. This is essential to ensure that the fabric performs optimally during flight, maintaining the necessary aerodynamic characteristics. The use of tension control lines is a standard practice in aircraft fabric covering, underscoring their importance in both safety and functionality.