What is the function of the Rotary Variable Differential Transducer (RVDT)?

• A. Measures rotor speed
• B. Measures fuel pressure
• C. Measures position of the twist grip for control inputs
• D. Measures collective position solely

Answer: (C)

The function of the Rotary Variable Differential Transducer (RVDT) is to measure the position of the twist grip for control inputs. This device is a type of sensor that translates the angular position of a control surface or component into an electrical signal. In the context of the TH-73 helicopter, the twist grip controls the throttle, and accurate positional feedback is essential for effective engine performance and flight control. The RVDT provides critical data to the control systems regarding the pilot’s throttle inputs, allowing for precise adjustments that support engine operation and overall aircraft performance.

While rotor speed and fuel pressure are vital measurements in helicopter operation, they are not the duties of an RVDT. The collective position is another important aspect of flight control, but it typically involves different sensors or systems dedicated to measuring the collective lever position rather than involving the twist grip specifically.