Extra 300/SC, Maintenance Manual, Page: 148 / 250

CHAPTER 51
PAGE 17
MAINTENANCE MANUAL EXTRA 300/SC
PAGE DATE: 12. February 2019
CONTROL SURFACE BALANCING
Weighing and Determination of Control Surface Moments
Balancing Mandrels
Prepare mandrels as shown on detail A in Figure 2 for
balancing the rudder and the elevator.
Prepare mandrels shaped as shown on detail B for balancing
the ailerons. Make the upper part of the mandrel rotatable for
the use of either the Rh or LH aileron.
Procedure
1 Remove the control surface (refer to chapter 27).
2 Reinstall the bolts in two brackets.
3 Put the control surfaces on the balancing mandrels (use a
wire for the trim tab). Refer to Figure 3.
4 Ensure weighing point and hinge cener axis are exactly on
the same horizontal plane.
5 Weigh by means of a conventional spring balance (kg/g-in-
dication) at the given weighing points and enter the
weight (m) in Figure 4. If negativ values are to be expected
place the spring balance in opposite direction (from the
weighing point downwards).
6 Measure distance of hinge center line to weighing point (r)
and enter the value in Figure 4.
7 Calculate the control surface moment (M) in Figure 4.
I M P O R T A N T If values exceed the given tolerances in Figure 4 con-
tact the manufacturer before beginning any changes of
control surfaces.
8 Reinstall the control surfaces.