TM 1-1520-240-10
7A-9-1
SECTION IX. CLIMB DESCENT
7A-9-1. Description.
a.
Climb and descent performance may be seen in
figure 7A-9-1, which represents change in torque to climb
or descend at selected GWs.
b.
The climb performance charts, figure 7A-9-2,
shows relationships between GW, initial and final altitude
and temperatures, time to climb, and distance covered
and fuel used while climbing. The chart is presented for
climbing at hotter and colder temperatures, intermedi-
ate torque (30 minute operation).
7A-9-2. Use of Chart.
The primary use of the charts is illustrated by the chart
examples.
a.
To determine torque change for a specific rate of
climb or rate of descent (fig. 7A-9-1), enter rate of climb
or descent and move right to gross weight, move down
and read change. This torque change must be added to
the torque required for level flight for climb, or subtracted
for descent, to obtain total climb or descent torque.
b.
Rate of climb or descent may also be obtained by
entering with a known torque change, moving upward to
gross weight, moving left and reading rate of climb or
descent.
c.
To use the climb performance charts (fig. 7A-9-2),
enter at the top left at the known gross weight, move right
to the initial press alt (pressure altitude), move down to
the FAT at that altitude, and move left and record time,
distance, and fuel. Subtract the time, distance, and fuel
values of the initial altitude-temperature condition from
those of the final altitude-temperature condition to find
the time to climb, distance covered, and fuel used while
climbing.
7A-9-3. Conditions.
The climb and descent charts are based on 100%
RRPM. The climb speed schedule shown in figure
7A-9-2 (see insert) is for optimum climb, that is, minimum
power required and maximum power available (30 min-
utes). It is an average schedule for the GW range and
atmospheric conditions for the CH-47D.