TM 1-1520-240-10
7-6-1
SECTION VI. TAKEOFF
7-6-1. Description.
The takeoff chart, figure 7-6-1, defines distances re-
quired to clear obstacles of 50 feet, 100 feet, 150 feet,
and 200 feet based upon maximum hover height capabil-
ity and true airspeed. The procedure for takeoff is the
level flight acceleration technique.
NOTE
The maximum hover heights shown are indica-
tive of helicopter performance capability and do
not imply that this hover height must be main-
tained through takeoff.
7-6-2. Use of Chart.
The primary use of the chart is illustrated by the exam-
ples.
a. To determine the distance required to clear an
obstacle, it is necessary to know maximum hover height
(hover capability), obstacle height, and climbout true
airspeed. Calculation of maximum hover height is
described in Section V, Hover. Enter the chart for the
required obstacle height, move right to desired true
climbout airspeed, then down and read distance required
to clear obstacle.
b. A hover check should be made prior to takeoff to
verify hover capability. If winds are present, hover
capability will be greater than predicted since the hover
chart is based on calm wind conditions.
7-6-3. Conditions.
a. The takeoff chart is based on calm wind
conditions. Since the surface wind velocity and direction
cannot be accurately predicted, all takeoff planning
should be based on calm air conditions. Takeoff into the
wind will improve takeoff performance.
CAUTION
A tailwind during takeoff and climbout will
increase the distance for obstacle clearance
and may prevent a successful takeoff.
b. Takeoff performance data are based on the use
of maximum torque available at 100% RRPM.
