Field ArTillery - US Army Center Of Military History

152 THE ORGANIZATIONAL HISTORY OF FIELD ARTILLERY
The first demonstration of massed fires based on the new concepts of adjustment
by any observer and the use of the new chart occurred at Fort Sill in the spring of
1931. There were two computer personnel and one forward observer, communicating
by voice radio. No map was used. Early experi ments with battalion-massed fires
showed that the three firing batteries rarely placed their impact centers on exactly
the same spot. Instead they delivered fire accu rately within a triangle of error, a
phenomenon caused by differences in site. 62 To solve the problem, Maj. Orlando
Ward, who followed Brewer as head of the Gunnery Department, suggested they
work back from the target by first adjusting on it, assuming zero site, and then plotting
battery positions by back azimuth 63 according to adjusted range. This method
of constructing firing charts was known first as back azimuth and later as observed
fire. 64
By the spring of 1933, some definite practical procedures for fire direction
had been established, and although the actual fire dir ection center was still in the
future, the term came into use. By using the observed fire chart, 65 it was possible
to send actual firing data by telephone or radio from the battalion to the batteries.
The procedure of having the observa tion post conduct fire by locating the target
and reporting the corrected data permitted the battalion opera tions (S–3) section,
employing the observed fire chart, to concentrate the battalion on the target. By this
time, a very defi nite fire direction group with specific duties had been estab lished
in the bat talion under the S–3. This fire direction group, however, handled only
observed fire; unobserved fires were directed by distributing overlays drawn from
the firing chart, and the batteries computed their own data by applying corrections
to compensate for weather or corrections previously derived by registration. In
1934, fire direction person nel included the S–3, two staff officers, a draftsman, and
a clerk. The officers computed the firing data, and the clerk assisted the draftsman
who prepared the charts. Personnel changes in 1934 resulted in the pioneers of the
fire direction center concept leaving Fort Sill for new assignments, and a three-year
hiatus in its development followed. 66
In 1937, Lt. Col. H. L. C. Jones took over a battalion of the 77th Field Artillery
at Marfa, Texas, and began to experiment with fire direction techniques. During
the previous experimental phase, Colonel Jones, while assigned to the Command
and General Staff School at Fort Leavenworth, had followed the developments
at Fort Sill closely. The first step Jones took was to make the battalion primarily
responsible for the preparation of unobserved fires, leaving the conduct of observed
fires to the batteries. To handle the new load, he added three officers (one computer
for each battery in the battalion) to the five persons es tablished in the battalion fire
62 Site is the difference in altitude between the firing piece(s) and the target.
63 Back azimuth is the azimuth plus or minus 180 degrees or 3,200 mils.
64 1st End, Col E. B. Gjelsteen to Comdt, FA School, 15 Mar 44, and Memo, Dunn to Comdt,
FA School, 21 Feb 44, FA School files; Ratliff, “Field Artillery Battalion Fire Direction Center,” pp.
117–18; Sunderland, “Massed Fire and the FDC,” p. 58.
65 At the time an observed fire chart, usually a gridded sheet, was one on which the relative locations
or batteries of a battalion and its targets were plotted data obtained as a result of firing.
66 “The Fire Direction Center,” pp. 4–5, FA School files; Sunderland, “Massed Fire and the FDC,”
p. 58; Annual Rpt, CofFA, FY 1933, p. 6, file 319.12, box 1331, Entry 37g, RG 407, NARA.