January-February - Air Defense Artillery

19.-13 A HOLE FILLER 51
Figure 3
:'Jaturally the fourth reason merits no consideration
whatever.
Now everybody knows that we've been getting too
much dispersion. Battery commanders have been
known to converge their guns at about the midpoint
of a target practice course to pick up more hits. Of
course this makes a very sour divergence under service
conditions if a target comes through at an azimuth different
bv 3200 mils from the azimuth
are conv~rged.
at which we
The Navy beats the rap by having the director compute
parallax separately for each gun. We have no
such scheme standardized,
See Figure 2.
but look what we can do!
We set a gun do-wn on the directing point of the battery.
This becomes the base piece. We put the other
three guns down radially about thirty-five yards away
from the base piece about 120 0
)
.apart. Now let's count
our gains.
1. 'VIle set in director displacement from the base
piece and leave it. If we get to shoot trial fire, 'we shoot
J
it ",,'ith this gun and have corrections for the battery
without manipulation,
1. \Ve have a pattern that can be concealed more
readily than even a rough square (or have we?).
3. If we have a secondarv antimechanized mission,
and embark on it, we can ~lways shoot at least three
guns without blasting another crew or two. In a square,
sometimes only two guns will be able to fire.
4. Any discussion of reduced dispersion 'would get
into dispersion ladders, twenty-five per cent rectangles,
and even twelve and one-half per cent boxes or dispersion
volumes of some sort to get the relative battery
probable errors of the two layouts. We might presume
that the average values of developed armament probable
errors in our antiaircraft artillery gun batteries are proportional,
in elevation, in deflection, and along the trajectory,
to those given in the firing tables, within certain
limits of accuracy. Anyhow, the witnessing of several
dozen calibration problems and a comparable number
of trial fire shots coupled with a small amount of
shooting at sleeves indicates that our guns consistently
shoot within :(. :(. :(.mils of the place where we think
we are pointing them. If by some chance everything
works out right using a square formation, we are consequently
missing the target by about :(.:(.:(.mils at mid
range, and shooting all around it. We've left a great big
hole right in the center of the pattern of bursts! By putting
one gun in the middle \ve can pretty \vell fill up
this hole with a lot of concussion and fast moving
fragments.
If we pull the three guns in radially so that they are
twentv or twenty-five yards from the center, we will fill
the hO'lefor sure: We ~hould also get some sort of centcr
of burst in the sky that will show us how we're doing.
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