Smart Avionics PB-4, Руководство пользователя интерфейса

Страница: 54 / 78

Note
The PB-4 does not actually say that the propeller is balanced or
not; it's left up to the operator to decide when to stop the process
based on the IPS reduction achieved.
7.7. After balancing
When the balancing has been completed, double-check that all balance weights
are securely attached. If you have been using temporary weights to carry out
the balancing, they should be replaced with permanent weights whose mass
and position are such that they have the same effect as the temporary weights.
If in doubt, recheck the balance once the permanent weights are installed.
Remove the sensors and the tape from the propeller blade. Make an entry in
the appropriate log book to record the vibration level achieved and the RPM
used.
7.8. Troubleshooting
This section provides answers to common problems that can arise when
balancing.
7.8.1. The displayed RPM is erratic or wrong
The RPM could be unsteady for the following reasons (most likely first):
• The optical sensor is not pointing at the reflective tape or the tape is not
parallel with the sensor's block. It may help to add one or more further strips
of reflective tape to increase the width of the reflective area.
• The optical sensor is either too close or too far away from the propeller.
• The angle of incidence of the light beam on the propeller blade is outside
the acceptable range.
• The sensor is being confused by extra reflections from shiny propeller
blades. Rotate the sensor to increase the angle of incidence of the light
beam on the propeller blade. You can also try adding non-reflective tape to
the other blades in the same position as the reflective tape.
• The engine RPM really is changing!
7.8.2. The current polar point position varies widely
This indicates that the vibration waveform is not consistent from one propeller
revolution to the next. This implies that some (perhaps most) of the measured
www.smartavionics.com 48
After balancing