DG Flugzeugbau LS4 - 5.2 Control surface weight and mass balance

Maintenance Manual LS4
Issued: May 2011
Copyright DG Flugzeugbau GmbH - any copy or publishing prohibited
Manual valid with the up-to-date cover page only
5-2
5.2 Control surface weight and mass balance
(Check when suspecting changes of mass and after repairs)
Weight and mass balance should be within given limits for safety against
flutter.
LS4 and LS4-a:
Surface
Mass
<kg>
<lbs.>
Horizontal
reference line
radius
<mm>
<in.>
Trailing edge load at
measuring point <kg>
<lbs.>
Elevator
1.41 up to 1.90
3.11 up to 4.19
Centreline of
section
148
5.83
0,33 up to 0,44
0.728 up to0.970
Rudder
3.70 to 4.50
8.16 up to 9.92
Centreline of
section
310
12.2
-0,04 up to +0,10
-0.088 up to +0.220
Aileron
3.50 up to 5.00
7.72 up to 11.02
Upper side
165
6.5
0,60 up to 0,80
1.323 up to1.764
LS4-b:
Surface
Mass
<kg>
<lbs.>
Horizontal reference line
Hinge Moment
<kg*cm>
<in. lbs.>
Elevator
1.41 up to 1.90
3.11 up to 4.19
Straight region of upper side
4.88 up to 6.50
4.24 up to 5.64
Rudder
3.70 to 4.50
8.16 up to 9.92
Centreline of section
0 up to 3.50
0 up to 3,04
Aileron
3.50 up to 5.00
7.72 up to 11.02
Upper side
10.00 up to 13.70
8.68 up to 11.89
Measuring technique for hinge moments: Control surfaces should be
attached individually at two bearings without any tension or friction.
Measure load at trailing edge with reference line level
Only LS4-b: Measure additionally radius from hinge line to measuring
point, multiply load and radius to yield hinge moment.
When using identical locations for measuring as used in final production
inspection, only trailing edge load must be checked.
Caution: Repairs are possible only in exceptional cases.
After changes of local static moments due to repairs, local mass balance must be
fixed in order to yield identical static moment values as in the factory-built
condition.