Question

which are true statements about hand metering units?

1. the control section and metering section are hydraulically and mechanically connected
2. in the metering section of the hmu the drive is splined to the rotor
3. the control section of the hmu includes a spool in a sleeve and pin
4. the spool, pin, drive, and sleeve turn at the same time when the steering wheel is turned

Explanation:

To determine true statements about Hand Metering Units (HMU), we analyze each option:

1. The control and metering sections of HMU are not hydraulically and mechanically connected (they operate with specific mechanical/hydraulic relationships, but this statement is incorrect).
2. In the metering section, the drive is splined to the rotor – this is a correct mechanical design feature of HMU.
3. The control section of HMU includes a spool in a sleeve and pin – this is a correct component description of the control section’s design.
4. When the steering wheel is turned, the spool, pin, drive, and sleeve do not all turn simultaneously (the spool’s movement is distinct from the rotational components in timing/function) – this statement is incorrect.

Answer:

1. In the metering section of the HMU the drive is splined to the rotor
2. The control section of the HMU includes a spool in a sleeve and pin