Smart Avionics PB-4, Руководство пользователя интерфейса

Страница: 59 / 78

rotor is viewed from above with the master blade pointing forward)
and a negative value is a shift to the left.
The relative pitch of the blades is commonly altered by
adding/removing shims where the blades are attached to the rotor
Blade
Pitch
hub bar. Some rotors provide a rotating or threaded adjuster. The
amount of pitch change required is normally very small. Our
convention is that a positive pitch value means that the master
blade pitch is increased (which automatically decreases the slave
blade pitch by the same amount) and a negative pitch value means
the master blade pitch is reduced (which automatically increases
the slave blade pitch by the same amount).
Blade pitch adjustments may be done when
tracking the blades
(making the tips fly at the same height). Here we do pitch
adjustments along with mass adjustments in a combined
balancing & tracking operation that we simply refer to as balancing.
Fig 8.2. Rotor Adjustments
What you need to know to balance the rotor is how much change (magnitude
and sense) is required for each of these adjustments. You can determine that
information using a polar chart that has been augmented with move lines. A
move line is literally a line drawn on a polar chart that shows the direction a
polar point would move when a particular adjustment is made to the rotor. A
move line is required for each adjustment you are going to alter. Each
accelerometer axis (X and Y) requires its own set of move lines.
8.3. Balancing procedure
Important
Before you start capturing any data, please ensure that the current
job has the correct polar options. Rotor mode should be selected
53 www.smartavionics.com
Balancing procedure