TM 1-1520-238-10
Change 2
7-69
Section VI. DRAG
7.22 DESCRIPTION.
The drag chart (fig 7-18) shows the change in frontal area
for each wing-stores combination that can be installed on
the helicopter. The baseline configuration does not in-
clude the Wire Strike Protection System (WSPS).
7.23 USE OF CHART.
To determine the change in frontal area ( F) and the as-
sociated multiplying factor, it is necessary to know what
combination of stores is installed. Enter the chart at the
top, move down to the illustration that matches the desired
combination, and then move right and read F and the
multiplying factor. Use the multiplying factor and data in
Section VI, Cruise to determine the resulting change in
torque.
7.24 CONDITIONS.
The drag chart is based on the primary mission configura-
tion having zero change in frontal area. If the WSPS is
installed, increase the frontal area for all configurations in
the drag table (including the primary mission configura-
tion) by 1.9 sq ft and increase the multiplying factor by
0.19.
