TM 11-6660-218-12
(11) The time in zone is determined from the
travel in meters, T is the time in zone in
fixed standards given in column 6 of DA
minutes and tenths, and S is the zone
Form 4469.
windspeed in knots. The values of the
windspeed are entered in columns 8 of
(12) Compute the zone windspeed by using
DA Form 4469.
Slide Rule ML-59 and the formula D/T
X0.0324 = S; where D is the horizontal
h. Ballistic wind determination for line 0 and
Figure 3-4. Plotting azimuth angle and horizontal distance.
line 1 are the same as the surface and the zone 1
line of the message. These plots take the form of
winds. Zone wind data recorded in columns 7 and
vectors. The sum of the zone winds vectors is the
8 are entered for ballistic wind data in columns 9
ballistic wind.
and 10 of DA Form 4469. The value of the ballistic
(1) Orient Plotting Board ML-122 with the
wind for any given line is determined by consid-
spaced parallel lines running from the
ering the zone winds of all zones from the surface
top to the bottom of the plotting board.
to the standard height of that line. To obtain the
The top of the plotting board represents
ballistic wind for any line above line 1, a plot is
North.
made of the weighted wind effect of each zone
which contributes to the ballistic value for that
(2) Select origin points for the lines to be
Change 8
3-13
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