DG Flugzeugbau LS4 - 2 Mass and Balance; Weighing Procedure

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
2-1
net tail load * b
Xcg= + a
empty mass
2 Mass and balance
2.1 Weighing procedure
Datum Line (DL): Under side of fuselage boom placed horizontal
Datum Point (DP): Leading edge of wing at root
1. Determine total mass by weighing all parts and adding together. For inflight
C.G. position, the pilot's mass must also be taken into account.
2. Assemble sailplane. For inflight C.G., the pilot must be seated in the
sailplane.
3. Raise tail on weighing machine until datum line is level using wooden blocks
or adjustable jack. (Check with leveling gauge)
4. Measure distance (b) from tail support to centre of landing gear axis.
5. Using plumb lead, determine points on floor perpendicular to left and right
datum points, and points on floor perpendicular to centre of landing gear
axis. Measure distance (a) from wheel axis to datum point.
Caution: The distances a and b may change with different masses due to deflection
of the landing gear and by setting of the rubber spring elements.
6. Determine tail load and deduct mass of additional auxiliary supports to get
net tail load.
7. If a battery may be fitted in the vertical fin the weighing must be done in this
configuration. Determine the mass of the battery separately by weighing
(max. 2.6 kg, 5.7 lbs.).
8. Weight and balance must be carried out at least every 4 years.
9. Calculate empty mass C.G. position for empty or non-existent vertical tail fin
tank: