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 7.7
corrected
Masses increments (
m
t1
,
m
t2
,
m
b ,
m
ao
) may assume positive or
negative values, because weight of mounted equipment is added and dismounted
–
subtracted. If equipment at particular place has not changed, then mass increment in
appropriate place is equal to 0. These increments values are given in the list of
equipment changes on reverse of „Calculation record of sailplane without pilots CG”
(item 18.4.)
Mounting or replacement of additional equipment on sailplane may move
sailplane without pilots CG (X
bp
) beyond the range specified in chart on
Fig. 7‒2.
Achieving correct position can be obtained by using additional fixed ballast described
in item 7.2. Following formulas for mass of front and rear ballast should be used
interchangeably, i.e., they are true only if one of the ballast has changed, either front
or rear.
Front ballast mass (m
bn
) determines from the formula:
66,22
X
X
X
m
m
k
bp
k
bp
1
bp
1
bp
bn
Rear ballast mass (m
bt
) determines from the formula:
k
bp
1
bp
k
bp
1
bp
bt
X
199,21
X
X
m
m
where:
(m
bp
)
1
– sailplane without pilots mass for new equipment
(X
bp
)
1
– sailplane without pilots appointed CG position for new equipment
(X
bp
)
k
– sailplane without pilots expected CG position with additional ballast
It is recommended to adopt for calculation (X
bp
)
k
value in the middle of range
allowed for (m
bp
)
1
before adding ballast.
The final value of sailplane without pilots mass (m
bp
) and corresponding CG
position (X
bp
) are as follows (see: record in item 18.4.):
bn
bp
bp
m
m
m
1
or
bt
bp
bp
m
m
m
1
ballast
with
X
ballast
without
X
X
k
bp
bp
bp
1
These values should be recorded in sailplane without pilots Weighing Table in
item 6.4. in Flight Manual.
