What type of motion does the TH-73A rotor head design allow for?

• A. Lead-lag
• B. Flapping
• C. Feathering (pitching)
• D. All of the above

Answer: (D)

The rotor head design of the TH-73A incorporates a sophisticated mechanism that allows for lead-lag, flapping, and feathering motion, which are all crucial attributes for helicopter rotor systems.

Lead-lag motion refers to the horizontal displacement of the rotor blades in relation to the rotor head during flight. This motion is essential for managing aerodynamic forces and maintaining stability in various flight conditions. The rotor design enables the blades to pivot slightly forward or backward, adapting to changing aerodynamic loads.

Flapping motion is the vertical oscillation of the blades around their pitch axis, allowing for adjustments in lift as the helicopter maneuvers. This motion is critical during turns, as the rotor blades need to change their angle of attack to sustain lift effectively.

Feathering, or pitching, involves the ability to change the blade angle of attack independently, which allows for control over lift and thrust. This feature is particularly important for optimizing performance during different phases of flight, such as hovering, climbing, or descending.

By facilitating all of these motions, the TH-73A rotor head design ensures efficient and stable flight, making it highly adaptable for various operating conditions. Each type of motion plays a vital role in overall rotor dynamics, contributing to the helicopter's performance and handling