SZD-54-2
„Perkoz”
TECHNICAL SERVICE MANUAL
SECTION 7.
SAILPLANE WEIGHING
Issue II
April 2014
Revision
Allstar PZL Glider Sp. z o.o.
Doc No. 542.4.02
page 7.1
corrected
SECTION 7.
SAILPLANE WEIGHING
7.1. Method of weighing
Method of sailplane weighing is presented in Fig. 7
‒1. Weighing should be
carried out on two scales with measurement accuracy
±0,44 lb. Method applies to
determination of mass and CG position of sailplane without pilots, as well as mass
and CG position of sailplane in flight configuration, that is with crew.
„Sailplane without pilots” term is explained in item 7.2.
Scales minimum weighing capacity at weighing sailplane without pilots must
not be less than:
- scale under front support (sailplane nose wheel)
– 660 lb;
- scale under rear support (sailplane tail wheel)
– 440 lb.
It is recommended to use both scales with capacity min. 660 lb, which will prevent
any damage to one of them by mistaken replacement at the supports. In case of
weighing a sailplane with crew it should be used scales with capacity min. 1100 lb
under front support.
During weighing it should be used a
„Record of sailplane weighing and
determining of CG” which is provided in Section 18. Weighing should be done in
sailplane configuration with plane wingtips (not with winglets). Check sailplane
completeness, compatibility of equipment with current „Equipment list” and remove
from interior any unnecessary items.
Supports should be placed under nose and tail landing wheel. Supports height
should be of adequate value so that chord line of wing root rib is in horizontal
position. Sailplane levelling should be checked with elastic transparent tube with
inner diameter of min.
0,25” filled with liquid (no air bubbles) by relating liquid level to
alignment point on leading edge and point on trailing edge at the same distance from
wing-fuselage parting plane. For one point exactly positioned on a liquid level in tube,
deviation for the second one must not be greater than
0,08”.
Chord line of wing root rib horizontal position can be obtained by using bar
(wedge) with an inclination 27:1000 arranged on upper conical portion forming tail
boom of the fuselage, within 31,5
” of trailing point of root aerofoil (Fig. 7‒1.).
Level difference between ends of bar, for 27,6
” long wedge, must not be greater than
0,04
”.