What type of rotor system allows for the least amount of movement in the blades?

A rigid rotor system is designed to minimize blade movement and flexing during flight. In this system, the blades are fixed at their root and share a solid connection to the rotor hub, allowing little to no vertical or horizontal movement. This rigidity leads to excellent efficiency and performance characteristics, particularly at higher speeds, since it reduces drag and aerodynamic losses associated with blade flapping and chordwise bending.

In contrast, other rotor systems, like the semi-rigid and fully articulated systems, allow for greater movement in the blades. The semi-rigid rotor system typically allows limited flapping and feathering, providing some flexibility but still maintaining a degree of rigidity compared to fully articulated systems. A fully articulated rotor system permits each blade to move freely, allowing significant flapping, feathering, and lead-lag movement. This flexibility can help distribute loads and enhance handling characteristics, particularly during maneuvers, but at the cost of increased complexity and drag.

Thus, the rigid rotor system stands out as the design that offers the least amount of movement in the blades, promoting efficiency and responsiveness.