Rotorcraft Flying Handbook, FAA-H-8083-21

Using the loading graph [Figure 19-2], the
moment/1000 of the pilot is found to be 9.1 poundinches,
and the passenger has a moment/1000 of 13.4
pound-inches.
1. Total Aircraft Weight
(Less Fuel) ...............................
Weight
(lbs.)
1,650
Moment
(lb.-ins.
/1,000)
176.4
3
LOADING GRAPH
3. Fuel...........................................
108
11.9
Load Weight in Pounds (x100)
2
1
0 2 4 6 8 10 12 14 16 18 20
Load Moment in Thousands of LBS - IN
A = Pilot
B = Passenger
D
A
C = Fuel
D = Baggage
B
C
Gross Weight in Pounds (x100)
18
17
16
TOTALS
1,758
CENTER OF GRAVITY ENVELOPE
Aft
Forward
188.3
15
Figure 19-2. A loading graph is used to determine the load
moment for weights at various stations.
Adding these figures, the total weight of the aircraft for
this flight (without fuel) is determined to be 1,650
pounds with a moment/1000 of 176.4 pound-inches.
[Figure 19-3]
Weight
(pounds)
Basic Empty Weight
1,315
Pilot
175
Passenger
160
Baggage
0
Total Aircraft (Less Fuel)
1,650
Max Gross Weight = 1,800 lbs.
Figure 19-3. Loading of the sample aircraft, less fuel.
Moment
(lb.-in./1,000)
153.9
9.1
13.4
0
176.4
The maximum gross weight for the sample aircraft is
1,800 pounds, which allows up to 150 pounds to be carried
in fuel. For this flight, 18 gallons of fuel is deemed
sufficient. Allowing six pounds per gallon of fuel, the
fuel weight on the aircraft totals 108 pounds. Referring
again to the loading graph [Figure 19-2], 108 pounds of
fuel would have a moment/1000 of 11.9 pound-inches.
This is added to the previous totals to obtain the total
aircraft weight of 1,758 pounds and a moment/1000 of
188.3. Locating this point on the center of gravity envelope
chart [Figure 19-4], shows that the loading is
within the prescribed weight and balance limits.
160 170 180 190 200
Gross Moment in Thousands of LBS-IN.
Figure 19-4. Center of gravity envelope chart.
PERFORMANCE SECTION
The performance section of the flight manual contains
data derived from actual flight testing of the aircraft.
Because the actual performance may differ, it is prudent
to maintain a margin of safety when planning
operations using this data.
SAMPLE PROBLEM
For this example, a gyroplane at its maximum gross
weight (1,800 lbs.) needs to perform a short field takeoff
due to obstructions in the takeoff path. Present
weather conditions are standard temperature at a pressure
altitude of 2,000 feet, and the wind is calm.
Referring to the appropriate performance chart [Figure
19-5], the takeoff distance to clear a 50-foot obstacle is
determined by entering the chart from the left at the
pressure altitude of 2,000 feet. You then proceed horizontally
to the right until intersecting the appropriate
temperature reference line, which in this case is the
dashed standard temperature line. From this point,
descend vertically to find the total takeoff distance to
clear a 50-foot obstacle. For the conditions given, this
particular gyroplane would require a distance of 940
feet for ground roll and the distance needed to climb 50
feet above the surface. Notice that the data presented in
this chart is predicated on certain conditions, such as a
running takeoff to 30 m.p.h., a 50 m.p.h. climb speed, a
19-2