What does the freewheeling unit contain to facilitate its function?

• A. Chain mechanism
• B. Sprag clutch
• C. Gear system
• D. Fluid coupling

Answer: (B)

The freewheeling unit functions primarily through the use of a sprag clutch. This component allows for the disengagement and engagement of parts within the drivetrain to enable smooth and efficient operation during various phases of flight or ground maneuvering. The sprag clutch is particularly beneficial because it allows the system to rotate freely in one direction while simultaneously locking together the components in the opposite direction. This mechanism facilitates the transfer of torque without excessive wear or resistance, ensuring optimal performance when the aircraft experiences changes in load or power demands.

The importance of the sprag clutch in the freewheeling unit lies in its ability to prevent back-driving of the engine during descent or when the power is not being applied, effectively ensuring that the system can operate reliably without the risk of damage to the engine or other components. This feature is crucial for the overall functionality and safety in flight operations. Other options might involve different mechanisms that do not provide the same benefits or are not typically utilized in the context of a freewheeling unit.