Transcript SDZ Construction: Mortars

SDZ Construction:
Mortars
Inter-service Resident Range Safety Course
(Intermediate)
Mortars tend to be low-velocity weapons
firing a fin- or spin-stabilized bomb at high
angles. They are often muzzle loaded and
may or may not be rifled.
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M224 60mm
Lightweight Mortar
M120 120mm
Heavy Mortar
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M252 (81mm) Medium Extended-Range Mortar
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M30 4.2 inch (107mm) Heavy Mortar
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Mortar Ammo
60mm
81mm
120mm
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M734A1 Multi-Option Fuze
The M734 multi-option fuze is the
U.S. Army’s standard electronic
multi-option fuze.
Proximity, near-burst, impact, and
delay settings are all provided in
this single fuze.
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M734A1 Multi-Option Fuze
PRX: Proximity
The fuze comes set to PRX
Burst height is 3 - 13ft. (1-4m)
NSB: Near-surface (nonjamming)
Burst height is 0-3 ft (0-1m)
IMP: Impact (SQ)
DLY: Delay (0.050 seconds)
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Mils Scale
Degrees
Scale
Index
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Indirect-Fire SDZ for Mortars
Area B
8PE
Target Area
Distance X
8PE
Area A
25°
Firing Point
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Legend for Mortars
Weapon:
Area A:
Ammo Type:
Area B:
Firing Point:
Map Scale:
Left Limit of Fire:
Map Sheet:
Right Limit of Fire:
Map Series:
PE (Range):
Map Edition:
PE (Deflection):
Date:
Distance X:
Name:
August 2003
Constructing an Indirect-Fire SDZ for
Mortars
Construct the SDZ for the 81mm M29
Mortar firing HE, M374A2.
Probable error, range (1 PER): 12m
Probable error, deflection (1PED): 6m
Dimensions for this SDZ are found in DAPAM 385-63, Chapter 10, Table 10-1 and
Figure 10-1.
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Reverse Engineering
Reverse engineering is used to create
SDZs when:
Physical or administrative boundaries
exist
A limited firing scenario is in effect
Detailed control measures are in place
Mission is directed
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Mission
All projectiles, to include all shrapnel, must
land within the impact area.
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Place the
following
reference
marks.
NU90031280
Plot the
coordinates
for the limits
of the Impact
Area.
+
NU91050920
NU93950915
Draw the
boundary of
the Impact
Area.
Plot the
firing point.
NU93951275
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NU93410820
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Scribe the
worst-case arc
just within the
downrange
boundary of the
impact area to
define the far
edge of Area B.
From Table 10-1, find
the measurement for
Area A.
Measurement for Area A = 400m
At the ends of the arc, measure
in 400m and draw tic marks.
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Draw straight
lines through the
tic marks to the
firing point.
These lines
establish the inside
limits of Area A.
From the inside limits
of Area A, measure
out 400m.
Draw tic marks.
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Draw straight
lines through
the tic marks.
These lines
establish the
outside limits of
Area A.
From the firing point,
measure 25° to the
right and left of the
inside limits of Area A.
Draw tic marks.
25°
25°
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From the firing
point, draw
straight lines
through the tic
marks.
This completes
Area A.
Area A
25°
25°
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From Table
10-1, find the
measurement
for Area B.
Area B = 400m
From the
downrange arc,
measure 400m
back towards the
firing point.
Draw a tic mark.
Area A
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From the firing
point, scribe an
arc through
the tic mark.
Area B
This completes
Area B.
Erase unnecessary
lines.
Area A
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From the firing
point, scribe an
arc through
the tic mark.
Area B
This completes
Area B.
Erase unnecessary
lines.
Area A
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Probable error
for deflection for
mortars is 8PE.
Area B
(PED) for this
weapon is 6m.
Compute the
probable errors for
deflection (PED).
8 x 6 = 48m (ˆ50m)
Measure 50m in from
the inside limits of
Area A.
Area A
Draw tic marks.
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Draw straight
lines through the
tic marks to the
firing point.
Area B
Probable error
for range for
mortars is 8PE.
(PER) for this
weapon is 12m.
Area A
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Compute the
Area B
probable errors
for range (PER).
8 x 12 = 96m (ˆ100m)
Measure 100m in
from the up range
limit of Area B.
Draw a tic mark.
From the firing point,
scribe an arc through
the tic mark.
Area A
This establishes the
maximum allowable range
for the mortar.
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This completes
the probable
error areas.
Area B
PE
Area A
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This completes
the probable
error areas.
Area B
PE
The Impact Area
has now been
defined.
Area A
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Scribe an arc
just inside the
up range
boundary of the
impact area as
shown.
Area B
PE
Measure
downrange the
value of Area B
(400m).
Draw a tic mark.
Area A
From the firing point,
scribe an arc through
the tic mark.
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Measure
downrange
the value of
the (PER)
(100m) to
the arc just
drawn.
Area B
PE
Draw a tic mark.
From the firing point,
scribe an arc through
the tic mark.
Area A
This arc establishes
the minimum
allowable range for
the mortar.
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Legend for Mortars
Weapon:
81mm M29 Mortar
Area A:
400m
Ammo Type:
HE, M374A2
Area B:
400m
Firing Point:
Map Scale:
1:50,000
Left Limit of Fire:
Map Sheet:
Right Limit of Fire:
Map Series:
PE (Range):
12m
Map Edition:
PE (Deflection):
6m
Date:
Distance X:
Name:
August 2003