Direction for firing in field artillery
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In
1915 the Artillery Inspection published a new Наставление за стрелбата
въ полската
артилерия
въ боя
(Direction for firing in field artillery), which introduced some substantial
changes in the direction published in
1908, based on the lessons learned from the Balkan wars. It was It
contains instructions for firing with all types of artillery that could be
used in a field combat, including those that Bulgaria did not yet have, i.e. :
1)
light field and horse guns; 2)
mountain guns and howitzers; 3)
light and heavy field howitzers; 4)
heavy
field guns. The
direction includes six sections : I.
Ballistic data concerning guns. II.
Action of the projectiles III.
Measure of the dispersion and calculation of the
corrections for shrapnel fire. IV. Preparation
of fire : determination of the range, laying the gun, direction of fire from
covered positions, measure of the angle of site, observation of the bursts,
perspective sketches. V.
Determination of the primary data, fire for
adjustment and fire for effect. VI. Fire
practice : demonstrative, training and fighting
fire. Instructions for writing firing reports. In
addition, an appendix contains an Instruction
for observing the artillery fire from aircraft that reflects the
experiences conducted during the siege of Odrin. The
direction includes also a firing table for both 75mm Schneider M. 1904 and
Krupp M. 1910 guns, containing data up to 8100 m, while the table published
in 1908 only went up to 6000 m. Trajectories. The introduction
and the first section are the same as the corresponding parts of the 1908
direction. The only addition is a discussion of the firing
trajectories : trajectories in which the distance of 4000 m is reached with
an elevation angle not exceeding 12°, are sloping,
such as those of the light and heavy field guns, trajectories in which this
distance is reached with an elevation angle greater than 12°, such as those
of mountain guns and howitzers, are curved. To obtain
a more curved trajectory for the same weight of the projectile and for the
same distance it is necessary to reduce the muzzle velocity and the battering
charge. Since the guns have only one charge, they could fire
at a single trajectory. The howitzers have several charges (from 3 to 7) and
at the same distance, they can fire, according to need, with different
trajectories. So selecting the distance and the corresponding charge, the
howitzer can obtain an angle of descent up to 48° and an angle of vertical
dispersion up to 60° with shrapnel and up to 200° for H.E. shell. At all distances the greater the dispersion in
height and width, the more sloping the trajectory. Dispersion in length is
not always greater for curved trajectories. The effective area in length is
as much larger as the trajectory is sloping. With the same muzzle velocity
and weight of the projectile, a greater curvature of the trajectory can be
obtained when the tip of the projectile is shaped to meet greater air
resistance Field
howitzers. The field howitzers are specially assigned to destroy the dugouts of the field
fortifications, to destroy the material of the enemy artillery, to destroy
buildings and to fire on live targets behind artificial shelters and in the
steep folds of the ground. They can be used together
with field guns for shelling animate targets in the open, for firing against
shield artillery and for destroying any kind of inanimate targets. Enemy
artillery is fired with mixed shells : shrapnel and
torpedo shell or H.E. shell with curved trajectories. Torpedo shell can be
uses also to fire at animate targets, especially when they are entrenched;
its action, even if weak in terms of material damage, has strong moral effect
on the enemy. Horizontal targets, such as the roofs of dugouts and weak
casemates, are fired with torpedo shell and the most
curved trajectory for the distance. Also animate targets hidden behind
artificial facilities - embankments, parapets, etc. - or in the folds of the area, are fired with curved trajectories, but with
shrapnel or torpedo shell. Animate targets in the open and vertical inanimate
targets (fencing walls, buildings, etc.) are fired
with full charge - at close range with shrapnel or torpedo shell. Universal
shell. The universal shell has
T&P fuze and can be used
by field and mountain guns and by howitzers at any range and against any
target. With time fire
universal shell has the same effect as shrapnel, after the burst its head continues
to move along its trajectory and, on impact, it bursts, scattering a great
number of splinters that fly in all directions. Bursting,
the head releases a red smoke, which makes
adjusting easier. Hitting a shield or a weak wall, the heads burst
into the barrier or very close behind it, hitting the nearby animate targets
with their splinters. Firing at troops in trenches, the heads that hit the
ridge of the rampart or the rear depression of the ditch burst and hit the
shooters with their splinters. With high bursts, the heads fly more
irregularly and some of them can turn and burst in the air before hitting the
ground. With percussion
fuze the universal
shell has a stronger effect than H.E. shells or common shells. Bursting it
produces a visible smoke, more destruction on inanimate targets and more
damage on animate targets. The fragments of cases and heads and some of the
bullets fly forward and sideways with considerable energy. To repel close
attacks, it is used as well as shrapnel, but its
effect is stronger. The effect of the universal shell of the
12cm howitzers is greater than that
of the shrapnel, because the shrapnel action is
strengthened by that of the head, which is larger, contains more
explosive, and acts as a separate shell. However, against thick earthworks or
strong armoured shelters, it cannot replace the torpedo shell. The part relating to the other types of projectiles
– shrapnel, H.E. shell for guns (бризантна
граната),
H.E. shell for howitzers (фугасна
граната,
previously called torpedo shell), common shell, case
shot – does not change. Shrapnel fire. The third section of the direction does not
present substantial differences with respect to the text published in 1908,
apart from some small corrections : – the
axes of the cone of the dispersion of the bullets at medium ranges is reduced
from 300/50 m to 150/30 m; – the
normal height of burst for howitzer is set at 3/1000 to 7/1000, instead of
3/1000 to 6/1000; – at
a range of 2500 m and with an interval of burst of 50 m
the average density of hits changes as follows : for light field and mountain
guns 1.5, for heavy field guns 1.85, for howitzers 1.35; – the area exposed to the shrapnel bullets for a skirmisher
lying down is reduced to 0.15 m (previously 0.20). In addition, the direction specifies that the
height of burst of the shrapnel is estimated in millièmes of the distance, and the interval of burst in
meters. Preparation of fire.
The primary firing data, that must be determined, are :
1) range, 2) deflection, 3) angle of sight – for indirect laying, 4)
corrector – for time fire, 5) width,
depth and kind of the target. The
range to the target can be measured on the map, obtained by telemeter, battery
telescope or field glasses, estimated by eye or by sound, as in the previous
direction. The
range according with the effectiveness of the fire is considered
: up to 1500 m close, from
1500 m to 4000 m mid, more than 4000 m great (the previous direction
distinguished the case of field guns from that of mountain guns and gave
slightly different data). As regards the angle of sight, the direction explains how to determinate it, not
only with the Schneider battery telescope, in use in the Bulgarian artillery
since 1904, but also with the Goerz panorama sight
and with the Krupp battery telescope, introduced only after the Balkan wars. The remaining part of this section does not
present any substantial differences, with the exception of the addition of a
large section on gun laying in general and from an open position. Gun laying.
When the battery is laid at an target, the lines of fire of its guns form a
sheaf, which can be: 1)
concentric (съсредочен)
if the lines of fire converge around a point in front of the battery. Up to
the point of convergence, the firing lines and the bursts converge and are in
the same order as the guns, at the point of convergence they come together,
and further they cross and walk, the bursts being in the reverse order of the
guns. In this case, the width of the front on which the bursts occur
increases as you goe along. In the crossfire, the
direction, distribution and transfer of fire is quite difficult. When the auxiliary aiming point is located between
the target and the battery : a) if the aiming point (A) is closer to the battery (B)
than to the target (T), the cross
at the target will be greater than the front of the battery (ex. 1); b) if
the aiming point is half the distance to the target, or closer to the target,
the crossing is equal to or less than the front (ex. 2-3); c) if the aiming
point is behind the target, the bursts at the target are in a regular order
and on a narrower front than that of the battery (ex. 4). 2)
walking (разходяш)
if the extended lines of fire converge around a point behind the battery. The
sheaf of the beaten front is larger than that of the battery and increases
with increasing firing range. The bursts order remains the same as the guns.
The collection of the sheaf and the correction of direction can be done easily (ex. 5). The further the aiming point
is moved back from the battery, the front width is
reduced. 3)
parallel (успореден)
when the firing lines are closely parallel to each other. At all distances,
the bursts are as wide as the front and in proper order. It occurs when the
guns are aimed in parallel directions or at very distant aiming points (30 km
or more), in front of or behind the battery (ex. 6). When needed, it can be easily moved, expanded and narrowed. An auxiliary aiming point located on the side
of the battery has the same properties as the corresponding aiming point
located in the direction of the battery and the target. |
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Laying from an open position.
If the target is clearly visible, the battery should fire directly at the
target, because each gun lays directly at the sector opposite it and all have
the same deflection. It is not clearly visible or its position is difficult
to indicate to the battery, it is preferable to lay with the aid of an
auxiliary aiming point. In any case, the first laying of the guns should be always done directly at the target. If
a battery commander sees that the target is not understood
correctly, he gives additional explanations, or assigns an auxiliary aiming
point for the whole battery. If he sees that the fire is
not properly distributed along the front of the target, he orders the
platoon commanders to change the laying of their guns. Against
dangerous targets close to the battery, each gun commander selects and
assigns a section for his gun from the front of the target opposite him. When
he considers that this section is sufficiently hit,
he transfers the fire of his gun to one of the adjacent sections. Laying from a masked or a covered position.
In this case, laying is always done with the aid of
an auxiliary aiming point and the elevation is given with the level or the
quadrant. To lay the guns, it is necessary to locate the approximate position
of the battery, to select an auxiliary aiming point, to determine the
auxiliary angle and the correction, and to lay the guns at the target. Laying
can be done simultaneously or sequentially, normally
by means of the battery tube according with the rules established in the
previous direction. Observation
of the bursts. The
observations are done with the help of binoculars
and if they are difficult, an auxiliary observer must be sent. However, when
there is the possibility of large errors in direction, it is best to look at the
first few shots with the naked eye, as they can occur outside the field of
view of the binoculars. To accurately estimate the
lateral deflections of the shells, the observer must be close to the firing
battery. As for the rules for the
observation of the fire, the directive introduces only two addition on time
fire : – for
the universal shell the trajectory can be judged by the fall of the heads in
all not very high burst; – when the observation point is
much higher than the target, the heights of the bursts are shown slightly
less than the actual ones, especially if the distance is not great. Perspective
sketch. This section of the direction does not present any
particular innovations regarding the preparation of the sketches, while it
slightly changes the way in which they are used to direct the fire, or to transmit what was seen from
the observation post with them, saying that it is necessary : a)
to indicate the number or
the name of the point around which a target appeared; b)
to show how far to the
right or to the left of that point the target right flank is and what the
target is; c)
to give the width of the
front of the target in millièmes; d)
to
give the distance to the target or its distance from here or there from the
specified point. |
