M113 APC

[ArmySGT.]

The M113 family of vehicles began as an Armored Personnel Carrier (APC) for transporting troops into battle and deploying them near an objective with supporting fire from a pintle mounted .50 cal Browning machineguns. The design called for the M113 to be both amphibious, and transportable, even air droppable. These design requirements forced the designers to use lightweight aluminum alloys and to lightly armor the vehicle. Originally meant to protect the crew and dismounts from cartridges of 7.62 NATO and below, as well as fragments from artillery shells up to 155mm detonating more than 30 meters distant, this armor level has been modified and upgraded by various users. At the time of the War (19 November 1989) the U.S. Army had thousands of these and variants in service, with the U.S. Air Force also using some for base defense. Thousands more can be found in the units of the National Guard and Army Reserves. Under programs to support state and local police forces some M113s or variants were transferred to civil control. It is therefore entirely possible for Project personnel to encounter this vehicle in the control of bandits, militias, splinter groups, or other hostile entities during the reconstruction… Data for the M113A2 and M113A3 base line APCs has been included.

The Morrow Project itself has acquired limited quantities of the M113A3 and variants for use by MARS personnel for situations that the common V-150 is unsuited. Additionally the project has acquired baseline M113 APCs and reconditioned them with the goal of supplying these to Law Enforcement at or below State level; as part of the reconstruction and support for Order mission. These APC models will be supplied from stocks prepositioned (without personnel) or from regional bases per the Commander on the ground. Typically this LEO variant will have rubber band tracks supplied by Soucy, civil band radios, CBR detection equipment, red and blue emergency lights, a Xenon spotlight, and be painted in a shade of blue with “Police” painted prominently on all four sides. Those in service with MARS personnel will either be in a baseline chemical resistant olive drab or location appropriate alternate camouflage scheme. The variants in use by MARS may include models in use by U.S. Allies and not necessarily U.S. Armed forces models. Those models for service with the Project have been modified to meet mission requirements such as the fusion power plant and electric drive systems, for those intended for use by other groups the diesel power plant remains.

The Council of Tomorrow team of industrial programs has maintained a “supply three, receive two” program. For each three hulls received, two are returned completely refurbished to the users specifications. Officially, the third hull is utilized for parts, and then scrapped. The hulls are actually reconditioned and refurbished to bring them up to Morrow Projects standards for use. The occasional hull that is to worn to be refurbished is destroyed in a show demonstration for defense auditors to maintain the deception. This “three for two” program is how models not in common use by U.S. Forces came to be Morrow Project standard. The profitability of the enterprise and the industrial cooperation has added much needed legitimacy to Morrow Project protocols and deceptions to hide the true nature of the Project.

[ArmySGT.]

What is the Ballistic Armor Value (AV) for the aluminum used as the hull and armor of the M113?

Can't be tremendous since it is rated only for 7.62x54R or lighter.

*edit* Aluminum (3rd edition, pg 38.)

AC 9 6mm = 0.7 cm of steel
AC 19 13mm = 1.02 cm of steel

6mm of aluminum is equal to 7mm of steel?

13mm of aluminum is equal to 12mm of steel?

25.4mm of steel is AC 48?

12.7mm of steel is not AC 24?

[nuke11]

Aluminum armor needs to be 3x as thick as it's RHA counter part for the same ballistics capabilities. This is not an exact formula, but will yield a close enough figure.

I believe the front of the M113 is proof against 14.5 mm.

The upper front armor is 38 mm @ 45 degrees and the lower front is 38 mm at 30 degrees.

For a good reference on the M113 family : http://afvdb.50megs.com/usa/m113.html

[ArmySGT.]

http://www.panzerworld.com/relative-armor-calculator

Frontal armor is 38mm at 45 degrees. Relative to a shot coming in a it is equivalent to almost 50mm of Aluminum.

http://www.panzerworld.com/relative-...r_thickness=35

[ArmySGT.]

M113A3 Hit Tables for the Morrow Project..pdfHit tables for the M113A3

Suitable for adding the M113A3 to

Liberation at Riverton (IMPS vehicle)
Operation Lonestar (1st Cavalry vehicle)

Give me your critique.. I have modified the M60A1 tables from Liberation at Riverton.

In the editing I may have missed changing some percentages or made something either too or less difficult to damage or destroy than is real world true.

Let's make this the best that can be!

[ArmySGT.]

Originally Posted by nuke11

Aluminum armor needs to be 3x as thick as it's RHA counter part for the same ballistics capabilities. This is not an exact formula, but will yield a close enough figure.

I believe the front of the M113 is proof against 14.5 mm.

The upper front armor is 38 mm @ 45 degrees and the lower front is 38 mm at 30 degrees.

For a good reference on the M113 family : http://afvdb.50megs.com/usa/m113.html

The problem I am having is slope..... the glacis is sloped.

Therefore, the table needs to factor in degree of slope for armor.

Angle increases depth relative to penetration.

[mmartin798]

If we assume that the relative thickness is defined by a line perpendicular to the vertical and the angle is measured from the vertical, then:

Relative Thickness = Actual Thickness / COSINE (Angle from vertical)

38 mm @ 45 deg gives 53.7 mm or 54 mm
38 mm @ 30 deg gives 43.8 mm or 44 mm

[nuke11]

Originally Posted by mmartin798

If we assume that the relative thickness is defined by a line perpendicular to the vertical and the angle is measured from the vertical, then:

Relative Thickness = Actual Thickness / COSINE (Angle from vertical)

38 mm @ 45 deg gives 53.7 mm or 54 mm
38 mm @ 30 deg gives 43.8 mm or 44 mm

For those doing this in Excel the formula is : =38/(COS(RADIANS(45))) = 53.74011537

Excel uses Radians instead of Degrees for COS, it does not do COSD like a calculator.

[ArmySGT.]

Here are the specs as known.

I wish I could find the website again to give the author full credit. M113 known specs.pdf

The armor thickness and angles are given.

This doesn't include various armor bolt additions that make the M113A3 tougher though denying the amphibious capabilities in most cases.

[ArmySGT.]

Originally Posted by nuke11

For those doing this in Excel the formula is : =38/(COS(RADIANS(45))) = 53.74011537

Excel uses Radians instead of Degrees for COS, it does not do COSD like a calculator.

Updated our favorite spread sheet with the slope VS thickness formula.

morrow_ex.xlsx

Next I will have to come up with a rational way to include the armor material into the formula. For right now the PD can work that out with the tables. Right now I think 1mm Armor plate equals AC 1 and 2.54 cm equals AC 48

Armor Class

Armor Material Cm of Cm of Cm of Cm of
Class Steel Wood Concrete Stone
A Skin - - - -
B Cloth (Heavy) - - - -
C Leather - - - -
1 13mm light - 2.54 .03 -
Plastic
2 13mm Heavy - 5.08 .5 -
Plastic

3 Chain Mail .25 7.62 .76 -
4 3mm Armor plate .34 10.16 1.06 7.62
5 .42 12.7 1.27 8.89
6 Nylon Body Armor .5 15.24 1.52 -
7 Resistweave Cloth .57 17.78 1.79 -
8 6mm Fiberglass .64 20.32 - -
Plate
9 6mm Aluminium .7 22.86 - -
Plate
10 .76 25.4 3.18 16.51
14 Kevlar Vest
15 1.02 34.29 7.62 22.86
16 19mm Lexan - - - -
18 Fiberglass / - - - -
Titanium Plate
19 13mm Aluminium - - - -
20 1.27 55.88 15.24 36.83
21 3mm Boron Carb- - - - -
ide Ceramic
25 1.52 55.88 15.24 36.83
30 1.79 66.04 19.05 43.18
35 3mm Boron/carbon 2.03 78.74 22.86 49.53
Filament plate
40 - 88.9 29.21 55.88
42 2.29 - - -
45 - 99.06 34.29 60.96
48 2.54 - - -
50 - 109.22 39.37 66.04
55 - 121.92 45.72 71.12
60 - 129.54 50.8 76.2
65 3.18 - - -
82 3.81 - - -
90 4.06 190.5 91.44 106.68
100 4.45 - - -
120 5.08 - - -
160 6.35 - - -
200 7.62 - - -
150 8.89 - - -
300 10.16 - - -
350 11.43 - - -
400 12.7 - - -