the field artillery journal - Fort Sill - U.S. Army

FD Technique for
Because of the practice of widely dispersing pieces within
the battery the problem of controlling the sheaf has become a
serious one. The problem can be partially solved by the use of
convergence tables and can be totally solved by the use of the
Sands graph. However, the corrections obtained by these
methods can not be readily checked by the S-3 or by his
assistants and, because of the several independent operations
involved, are subject to numerous errors.
The fire-direction technique outlined below is not proposed as
a universal one, but rather for use when normal fire-direction
methods will not produce satisfactory data. It is particularly
applicable to heavy artillery where accurate data are essential.
SURVEY
Locations of all pieces must be plotted on the firing chart.
Time available
and accuracy desired will decide whether each
piece is located by survey or whether only one piece of each
battery is located by surv ey and the remaining pieces of the
battery
paced in by the battery executive.
One piece, henceforth called the battalion base piece, is laid
on the base point. All other pieces of the battalion are laid
parallel to the battalion base piece. When a common orienting
line is used all batteries will be laid with the same base angle.
If more than one orienting line is necessary, only the
differences in the directions of the orienting lines have to be
considered in computing the base angles.
By Maj. C. R.
Oliver, FA
Heavy Artillery
FIRING CHART
The firing chart is identical with that used in normal firedirection
procedure, with the following exceptions:
(1) The locations of all pieces are plotted on the chart.
(2) Only the base line of the battalion base piece is drawn
on the chart.
(3) Along this base line a point is arbitrarily selected,
marked, and labeled "Data Point." The data point should be as
near the center of the battalion area as possible. The battalion
base piece itself may be used as the data point. When the data
point has been selected, the range-deflection fan is seated at it,
and an inverted arrow is placed on the base line ⅛ inch beyond
the deflection are which is to be used in measuring shifts.
Fig. 1 shows the essentials of the firing chart.
Figure 1. Firing chart.
blank to hold it in place once it is oriented on the firing chart.
Should masking tape be unavailable, adhesive or scotch tape
may be used. Covering the edges of the masking (adhesive)
tape on the templet blank with scotch tape prevents the range-
THE TEMPLET BLANK
deflection fan from catching on them, and consequently
A blank templet is made from a rectangular piece of facilitates measurements.
transparent celluloid, about .005 inch thick. One side should be Fig. 2 illustrates the completed templet blank. (Note: The
frosted to facilitate writing thereon. If frosted celluloid is not masking tape, shown in this figure, is omitted in other
available the clear issue celluloid may easily
be frosted with illustrations.)
sandpaper. Tracing paper or cloth is a usable substitute for the All essential
data for any position occupied is placed on the
celluloid. The templet blank should be only large enough
to templet in pencil in order that it may be easily erased, leaving
insure its covering any position area plotted
on the firing chart. the templet blank ready for the next position.
Once the templet
A series of parallel
lines are drawn
along one edge of the blank has been prepared its
usefulness is practically unlimited.
piece of celluloid. Spacing
between the lines is immaterial, but
it should be regular.
Sufficient lines should be drawn to insure
coverage of a complete
grid square on any probable firing
chart.
Three pieces of masking tape are placed on the templet
PREPARING THE TEMPLET
When the firing chart is complete (Fig. 1), the templet
blank is placed over the position area so the lined edge of the
blank is toward
the target area and the lines on the templet
are parallel to the grid lines (Fig. 3a). The blank
is secured by
820 FIELD ARTILLERY JOURNAL—December, 1944
the masking tape, and the positions of all pieces and of the