July-August - Air Defense Artillery School

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Figure 2
t here are several reasons for this. First, in the use of l.T.C.
e type of lead studied and applied is the travel lead, based
the line of Right of the target: obviously this type of lead
n be adjusted only after line shots are obtained. \;\,lhere
rei leads are in angular values (mils), the lead angles
e in the inclined plane determined by the gun and the
rget's line of Right. A second and rather obvious reason
r line shots is that all hits must necessarily be line shots;
~ fact a hit might well be defined as a line shot to which
s been applied the correct lead. A third significance of
fine shots lies in the fact that this is the only positive way
which shots can be sensed as ahead or behind, depending
pectively on whether the tracer appears eclipsed by the
rget or superimposed against it. This type of sensing reuires
good eyesight and is rendered less effective by
aller target, increased range, and higher target speed.
Figure No. 1 c.
LT.C. \VITJIOlIT SIGHTS
The use of pure individual tracer control without help of
ghts has not produced fully satisfactory results in practice.
I~e of the reasons for this are as follows:
• a. Due to the fact that A1\ machine guns are mounted
r below the gunner's eye height it is generally impossible
place the opening shots anywhere near the line of Right
the target. The additional time required to obtain line
shotsafter fire is opened sacrifices precious seconds as well
much ammunition.
b. There is no known method of applying an opening
, either linear (target lengths) or angular (mils), if
gunner has nothing to indicate the exact direction in
hich his gun is pointed.
c. The gunner is provided with no "tracking point" to
tnable him to follow the target's angular motion. Experi-
ence on other types of guns with telescopic sights has indicated
the necessity for smooth tracking if hits are to be
obtained.
d. On a brioht o dav. it is often impossible
against the sky with the naked eye.
to see tracers
e. Due to the many difficulties pre\'iously mentioned
under Tracer Observation it has been found difficult to
adjust fire intelligently, even after line shots have been
obtained. Furthermore, it is difficult to apply small adjustments
to the lead unless the target is being tracked with
the aid of some form of sight; this is due to the fact that the
gun has a basic rate of traverse due to the target's motion.
and this rate varies throughout the course, being a maximum
at the midpoint-the difficulty of applying a fine lead
correction on top of this varying rate should be obvious.
It should be here remarked that, except for very brief
courses at short ranges, the exclusive use of sights without
regard to tracer observation will be found just as unsatisfactory
as the opposite extreme here discussed.
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LT.C. AWED BY SIGHTS
Sights must be mounted in the nomlal line of the gunner's
sight and so designed as to permit a full field of view;
creation of small dead areas by the mount or sight elements
is not permissible. The sight must therefore be either a
simple rinoo sioht 0
form of ring sight
(front and rear) or the more advanced
known as the forward area sight. This
form
graph.
of sight will be separately discussed in a later para-
The extent to which the sights will be used is dependent
upon the course, range, and time available for firing; it may
depend also to some degree upon the eyesight and indi-
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L)'./~"oI,;' ~,.c6. L".-/.4d', .. N,¥II.
a. Incline"! PI"", 0/ Tr",v,1 Le",d.
c. E/e,"""b 0/' ~ fr T~v ..1 Lecg's.
Figure 3
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