There are many types of armor in the real world each of varying effectiveness. Often what works against one weapon may not work against another. It is needless to say, a complex subject. All things considered, simulating such a wide variety is nearly impossible in a game system that seeks to avoid an unplayable level of complication.
We can however apply a much simplified model to the question. The following table is based upon RHAe (Rolled Homogeneous Armor Equivalent), a standard for measuring weapon penetration and armor effectiveness. One can consider the base for RHAe to be hardened steel, and thus the thickness of a simple steel armor can be referenced directly after accounting for armor slope.
The resulting Defense values are based upon the standard progression rate for these house rules: 1.53779192x. A conversion from GURPS third edition DR ratings (which seem to be based upon the same RHAe standard) is also provided for conversion from GURPS Vehicles 2nd edition.
|
RHAe
Armor Conversion |
||
|
Armor
(mm) |
GURPS
DR |
HERO
Def |
|
0.12 |
0.3 |
1 |
|
0.24 |
0.7 |
2 |
|
0.36 |
1.0 |
3 |
|
0.56 |
1.5 |
4 |
|
0.86 |
2.4 |
5 |
|
1.32 |
3.6 |
6 |
|
2.03 |
5.6 |
7 |
|
3.12 |
8.6 |
8 |
|
4.80 |
13.2 |
9 |
|
7.38 |
20.3 |
10 |
|
11.35 |
31.3 |
11 |
|
17.45 |
48.1 |
12 |
|
26.84 |
74.0 |
13 |
|
41.27 |
113.7 |
14 |
|
63.46 |
174.9 |
15 |
|
97.59 |
268.9 |
16 |
|
150.07 |
413.6 |
17 |
|
230.78 |
636.0 |
18 |
|
354.89 |
978.0 |
19 |
|
545.75 |
1504.0 |
20 |
|
839.25 |
2312.9 |
21 |
|
1290.59 |
3556.7 |
22 |
|
1984.66 |
5469.5 |
23 |
|
3051.99 |
8411.0 |
24 |
|
4693.32 |
12934.4 |
25 |
|
7217.35 |
19890.3 |
26 |
Sources vary in how they list Armor thickness values. Many today use RHAe, others may simply give actual thickness and list the type of armor. The latter case requires one to either convert the listed value to RHAe, or to apply a DEF modifier after consulting the above table. Aluminum armor for example (like that found on the old US Army M113 APC) should halved to give a rough RHAe value.
Increased or reduced effectiveness against certain types of weapons may be handled by specific modifiers. Chobham Armor like that found on the US Army M1A1/A2 battle tanks for example is more effective against HEAT or other shaped charge weapons, and should be granted a +2 defense against those weapons as a result.
All Vehicle Armor is considered to be Barrier Defense under these house rules.
Sample Vehicles:
|
M1A1HA Battle Tank |
Turret
Armor |
|||||
|
|
Front |
Side |
Back |
Top |
|
|
|
|
20* |
17* |
17 |
13 |
|
|
|
|
Hull
Armor |
|||||
|
|
Front |
Side |
Back |
Top |
Bottom |
Tracks |
|
|
20* |
16* |
13 |
13 |
13 |
10 |
|
|
|
|
|
|
|
|
|
|
*Armor adds +2 vs.
HEAT or Shape Charge attacks |
|
||||
|
|
|
|
|
|
|
|
|
|
Armament: |
|
|
|||
|
|
|
Co-Axial 7.62 GPMG |
|
|
||
|
|
|
Top Mounted: .50 Cal
M2 Browning HMG |
||||
|
|
|
Top Mounted: 7.62mm M2
Browning GPMG |
||||
|
|
|
|
|
|
|
|
|
M60A3 Battle Tank |
Turret
Armor |
|||||
|
|
Front |
Side |
Back |
Top |
|
|
|
|
18 |
16 |
16 |
12 |
|
|
|
|
Hull
Armor |
|||||
|
|
Front |
Side |
Back |
Top |
Bottom |
Tracks |
|
|
17 |
15 |
13 |
12 |
12 |
10 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Armament: |
|
|
|
||
|
|
|
Co-Axial 7.62 GPMG |
|
|
||
|
|
|
Top Mounted: .50 Cal
M2 Browning HMG |
||||
|
|
|
|
|
|
|
|
|
T-72 Battle Tank |
Turret
Armor |
|||||
|
|
Front |
Side |
Back |
Top |
|
|
|
|
18* |
16 |
16 |
12 |
|
|
|
|
Hull
Armor |
|||||
|
|
Front |
Side |
Back |
Top |
Bottom |
Tracks |
|
|
17 |
15 |
14 |
12 |
|
10 |
|
|
|
|
|
|
|
|
|
|
*Armor adds +1 vs.
HEAT or Shape Charge attacks |
|
||||
|
|
|
|
|
|
|
|
|
|
Armament: |
|
|
|
||
|
|
|
Co-Axial 7.62-mm (7.62x 54R)
Machinegun PKT |
|
|
||
|
|
|
Top Mounted: 12.7-mm
(12.7x108) AA MG NSVT |
||||
|
Common
Armor Values: Turret Front |
||
|
Vehicle |
Armor (mm) |
DEF |
|
|
|
|
|
M3 Halftrack |
12 |
11 |
|
M3 Stuart |
38 |
13 |
|
Sherman |
63 |
14 |
|
Tiger |
100 |
16 |
|
T-34 |
90 |
15 |
|
|
|
|
|
M113 |
19 |
12 |
|
Bradley |
130 |
16 |
|
|
|
|
|
M48 |
200 |
17 |
|
T-62 |
210 |
17 |
|
M60A1 |
210 |
17 |
|
T-55 |
230 |
17 |
|
M60A3 |
240 |
18 |
|
T-72 |
330 |
18 |
|
M1A1 |
450 |
19 |
|
M1A1HA |
680 |
20 |
|
M1A2 |
950 |
21 |