TM 55-1520-228-10
6-2 Change 14
6-4. LOADING CHARTS.
a. Information. The loading data contained in this
chapter is intended to provide information necessary to
work a loading problem for the helicopters to which this
manual is applicable.
b. Use. From the figures contained in this chapter,
weight and moment are obtained for all variable load
items and are added to the current basic weight and
moment (DD Form 365-3) to obtain the gross weight and
moment.
6-5. CENTER OF GRAVITY LIMIT CHART
(Figure 6-2).
a. The gross weight and moment are checked on
figure 6-2 to determine the approximate center of gravity
(cg).
b. The effect on cg by expenditures in flight of such
items as fuel, etc., may be checked by subtracting the
weights and moments of such items from the takeoff
weight and moment and checking the new weight and
moment on the center of gravity limit chart.
c. If the weight and moment lines intersect be-
tween the forward and aft limit lines, the helicopter is
within flight limits.
NOTE
This check should be made to deter-
mine whether or not the cg will remain
within limits during the entire fight.
6-6. CARGO SPACE (Figure 6-3).
The cargo space chart provides information necessary
to ensure that maximum cargo weight does not exceed
the amount specified for different helicopter configura-
tions.
NOTE
Cargo space chart is used in conjunc-
tion with figure 6-1 and figure 6-2 to com-
pute parameters of the loading charts
contained in this chapter.
6-7. CARGO PLATFORM.
CAUTION
To prevent damage to floor of cabin,
no cargo will be placed on floor of
helicopter. The cargo platform will be
installed whenever cargo is to be
carried.
The cargo platform will be installed in the cabin for cargo
handling. The platform is a two-piece construction of
plywood sheeting. Provisions are made for mounting to
existing fuselage hardware. The strength of the cargo
tiedowns on the cargo platform is 2100 pounds.
6-7.1. CARGO RESTRAINT CRITERIA.
The amount of restraint that must be used to keep the
cargo from moving in any direction is called the “restraint
criteria” and is usually expressed in units of force of
gravity, of G’s. Following are the units of the force of
gravity of G’s needed to restrain cargo in four directions:
Direction Cargo
Forward
8 G’s
Rear 8 G’s
Lateral 4 G’s
Vertical 8 G’s (up)
8 G’s (down)
6-8. FUEL LOADING CHART (Figure 6-4).
The purpose of the fuel loading chart is to provide mo-
ment/100 for varying quantity (gallons and/or weight in
pounds) for either JP-4, JP-5, or JP-8 fuel.
NOTE
Auxiliary tank in the passenger area.
a. For a given weight of fuel there is only a very
small variation in fuel moment with change in fuel specif-
ic weight. Fuel moments should be determined from
figure 6-4. Use the scale for the specific weight closest
to that of the fuel being used.
b. The full tank usable fuel weight will vary depend-
ing upon fuel specific weight. The aircraft fuel gage sys-
tem was designed for use with JP-4, but does tend to
compensate for other fuels and provide acceptable
readings. When possible the weight of fuel onboard
should be determined by direct reference to the aircraft
fuel gages.
c. The following information is provided to show
the general range of fuel specific weights to be ex-
pected. Specific weight of fuel will vary depending on
fuel temperature. Specific weight will decrease as fuel
temperature rises and increase as fuel decreases at the
rate of approximately 0.1 lb/gal for each 15 degrees
centigrade change. Specific weight may also vary be-
tween lots of the same type fuel at the same temperature
by as much as 0.5 lb/gal. The following approximate fuel
specific weights at 15 degrees centigrade may be used
for most mission planning:
FUEL TYPE SPECIFIC WEIGHT
JP-4 6.5 LB/GAL
JP-5 6.7 LB/GAL
JP-8 6.7 LB/GAL
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