M113a3

[Phaelen Bleux]

I need to finish the bio, but I thought I'd post this design preliminarily to get any feedback anyone wants to give.

Body +4, heavy frame, standard materials with standard tracks and limited rotation open mount. Improved brakes, improved suspension, waterproof.

Armor: DR 50 overall; 60 degree slope in front for DR 100 and 30 degree slope for DR 75 in rear. Spall liner.

Improved tracked drivetrain with 205-kW improved turbocharged diesel engine. 95 gallon self-sealing standard tanks. Truck Lead-Acid battery pack (8,000 kWs).

M2HB MG with 1,000 rounds.

Short Range radio with Scrambler, Compact Fire Suppression system, Environ Control for 13, Military GPS, 2 NCS, 11 NPS.

The design runs 3% light at this point.

[Langy]

I'm guessing your designing that with Vehicles for GURPS third edition? Why not just stat it out from the actual statistics, rather than designing it in Vehicles?

[Phaelen Bleux]

Originally Posted by Langy

I'm guessing your designing that with Vehicles for GURPS third edition? Why not just stat it out from the actual statistics, rather than designing it in Vehicles?

Yes, it will be a 3e design. I guess I'm just a glutton for punishment in math exercises.

And actually, I was wondering about my stats for DR anyways--which are derived from real-world armor sources.

[HANS]

Originally Posted by Phaelen Bleux

Body +4, heavy frame, standard materials with standard tracks and limited rotation open mount. Improved brakes, improved suspension, waterproof.

Many people would question the "improved" suspension ;) The gun mount has a 360° traverse.

Originally Posted by Phaelen Bleux

Armor: DR 50 overall; 60 degree slope in front for DR 100 and 30 degree slope for DR 75 in rear. Spall liner.

Without the optional add-on armour, the M113A3 has on the HF 38mm aluminium armour, for DR 30. The slope probably increases this to DR 50 or so. The HS has 44mm alu, for DR 35. The HB I have no data, but DR 35 is a good guess. The HT and HU have only 12.7mm, for a mere DR 10. The M113A3 had improved HU armour, but I'm not sure of its exact improvement. Probably not better than the HS. I'm still thinking how to model spall liners. The add-armour may bring it up to the figures you have on the HF and HS.

Originally Posted by Phaelen Bleux

Improved tracked drivetrain with 205-kW improved turbocharged diesel engine. 95 gallon self-sealing standard tanks. Truck Lead-Acid battery pack (8,000 kWs).

Not sure about the self-sealing, need to read up on that. No on the batteries. The thing uses four batteries with 4,320 kWs each, for 17,280 kWs.

Originally Posted by Phaelen Bleux

Short Range radio with Scrambler, Compact Fire Suppression system, Environ Control for 13, Military GPS, 2 NCS, 11 NPS.

No on the fire suppression. Even the M113A3 still has a lame old manual system.

Cheers

HANS

[Phaelen Bleux]

Gun traverse noted.

The armor DRs are more what I was looking for. I finally found values of 3.8 cm FTB, 3.18-4.45cm RL, and 3.18cm U. However, multiplying mm by 2.8 as in Vehicles Lite, I was getting DRs of 75-100. Seemed excessive for a lightly armored APC. What is your conversion??

The gas tanks are mounted on the outside of the APC; figured self-sealing would be in order, although that is an assumption of mine.

Knew there were 4 batteries; thanks for the kWs.

And I'll call it just a plain old Fire Extinguisher, then. I'll use stats from Robots.

I think I need to find some better sourcebooks to start from. Thank you very much for the input--it's just what I was hoping for!!

[HANS]

Originally Posted by Phaelen Bleux

The armor DRs are more what I was looking for. I finally found values of 3.8 cm FTB, 3.18-4.45cm RL, and 3.18cm U.

It has to be 12.7mm (DR 10) somewhere, cause that is what JANE'S ARMOUR AND ARTILLERY says (which is usually mostly right ;) ). I'm guessing either HT or HB, or both. The HU was famous for being notoriously easy to penetrate not only by mines, but also by small arms when traversing a ridge (then again, the whole thing was only protected against 7.62x54mmR). As I said it got uparmoured on the M113A3 (IIRC even already on the A2), but that was steel applique; the original alu hull is probably still very thin.

Originally Posted by Phaelen Bleux

However, multiplying mm by 2.8 as in Vehicles Lite, I was getting DRs of 75-100. Seemed excessive for a lightly armored APC. What is your conversion??

Aluminium alloy armour offers only 1/3 the protection of RHA steel. So instead of multiplying the mm by 2.755, use 0.83.

Originally Posted by Phaelen Bleux

The gas tanks are mounted on the outside of the APC; figured self-sealing would be in order, although that is an assumption of mine.

I doubt it.

Originally Posted by Phaelen Bleux

I think I need to find some better sourcebooks to start from. Thank you very much for the input--it's just what I was hoping for!!

You're welcome.

Cheers

HANS

[Phaelen Bleux]

Originally Posted by HANS

It has to be 12.7mm (DR 10) somewhere

Aluminium alloy armour offers only 1/3 the protection of RHA steel. So instead of multiplying the mm by 2.755, use 0.83
HANS

I also had a source that gave a range of 12-44mm. I agree; must be top and under. There are add-on kits to beef up belly DR.

Where is the rule for aluminum vs. steel DR?

I dropped the self-seal tanks and found a source that listed IR (seems likely in today's battlefield). I decided to go for a Cheap structure to beef up loaded weight; otherwise the design was off by more like 18%. Besides, what army doesn't go for Cheap?

Again, thanks for all the help, Hans.

[DouglasCole]

Originally Posted by Phaelen Bleux

Gun traverse noted.

The armor DRs are more what I was looking for. I finally found values of 3.8 cm FTB, 3.18-4.45cm RL, and 3.18cm U. However, multiplying mm by 2.8 as in Vehicles Lite, I was getting DRs of 75-100. Seemed excessive for a lightly armored APC. What is your conversion??

Is it whatever cm of aluminum, or steel? If it's aluminum, that's the distinction, since 1mm = 2.75DR only works for RHA steel.

Edit: Ich hast been der NINJA'D!!


(Eurotrip: "I speak bad German.")

[Phaelen Bleux]

M113A3 APC
Developed in the late 1950s, the M113 was one of the first "battle taxis" to enter service with the U.S. armed forces. Made primarily of airplane grade aluminum rather than steel, the vehicle is very light for its size, allowing it to be air transportable, air droppable and swimmable. Its utility rapidly turned it into the foundation for a much larger family of vehicles, such as the M577 and M106.
The M113 carries 11 soldiers in bench seating along the inner sides of the vehicle, with a commander sitting in the middle of the APC and the driver in the front left. The M113A2 has seen action in Vietnam (where the Viet Cong called it the "Green Dragon") and Desert Storm. In Desert Storm, it was decided that the A2 was underpowered and unable to keep up with the Abrams tank, leading to the addition of the RISE package in 1987. This upgraded the diesel engine to a turbocharged version, improved driver controls, moved the fuel tanks to the exterior of the vehicle and added a composite spall liner. The M113A3 has provisions for mounting 14.5mm of external steel armor (DR 40), and by 2006 is expected to feature high speed digital networks and data transfer systems.
The M113A3 is in service in over 50 countries. Over 28,000 A3s are currently in service, and total production of the M113 line exceeds 80,000 vehicles. It has a clearance of 16", can climb obstacles 24" tall, a cruising speed of 3.6 mph in water, and a cruising range of 300 miles.
The M113A3 burns 7.2 gallons of diesel per hour. Visibility is poor.

Subassemblies: Body +4, Tracks +3, full rotation Open Mount +0.
Powertrain: 205-kW Improved Tracked drivetrain with 205-kW Improved Diesel turbocharged engine, four 4,320-kWs lead acid batteries.
Fuel: 95 gallons diesel (Fire 9).
Occupancy: 2 NCS, 11 NPS
Cargo: 0 cf.

Armor F RL B T U
Body: 6/70 4/35 4/50 3/10 3/10
Tracks: 4/35 4/35 4/35 4/35 4/35

Weaponry:
12.7mm Machine Gun/M2HB (2,000 rounds Solid).

Equipment:
Body: Spall liner, short-range (3-mile) radio with scrambler, two fire extinguishers, military GPS, passive IR (3-mile), periscope, 13-person environmental control.

Statistics:
Size: 16'x8.8'x7.2' Payload: 1.65 tons Lwt.: 13.6 tons
Volume: 882 cf. Maint.: 43 hours Price: $214,961

HT: 12. HPs: 1,200 Body, 430 each Track.

gSpeed: 41 gAccel: 3 gDecel: 15 gMR: 0.5 gSR: 7
Ground Pressure Very Low. 4/5 Off-Road speed.

Design Notes:
Body is 550 cf; tracks are 330 cf; open mount is 2 cf. Structure is Heavy, Cheap. It has Improved Brakes (an exception to the Wheeled only rule), Improved Suspension and is Waterproof. Armor is expensive metal with 60-degree slope in the front and 30-degree slope in the rear. Mechanical controls. Empty weight is 23,880 lbs. Design loaded weight was increased 6% to match real-world values. Design gSpeed was 50 mph; the real-world value is shown. One of the fire extinguishers is portable; the other is confined to the engine compartment. Some sources state the M113A3 has an NBC system; this would require the vehicle to be Sealed.

Variants:
The M113 (1960) featured a 160-kW gasoline engine and 80 gallon fuel tanks. gSpeed 37 mph; cruising range 200 miles.
The M113A1 (1964) introduced a 158-kW diesel engine and 95 gallon fuel tanks for improved range. gSpeed 37, range 300 miles.
The M113A2 (1979) improved the engine cooling system and suspension.
The M113 chassis has been used for a bewildering array of derivatives, including but not limited to the M58 Wolf smoke generator carrier, M106 self-propelled 107mm mortar, M113 AMEV medvac, M125 self-propelled 81mm mortar, M548 cargo carrier, M577 command post carrier, M730 Chaparral guided missile equipment carrier, M901 improved TOW vehicle, M981 fire support team vehicle, M1059 Lynx smoke generator carrier, M1064 self-propelled 120mm mortar, M1068 standard integrated command post system carrier, and M1108 universal carrier.

[HANS]

Originally Posted by Phaelen Bleux

M113A3 APC "Gavin"

Oh, for the love of . . .

No, no, and no. Absolutely freakin noone calls it "Gavin" except for one second lieutenant formerly of the Army who has a grudge against the Marines and just about everything in the US military except for the "Gavin," a mythical vehicle that is the solution to all of America's fighting problems . . .

http://home.comcast.net/~genericdad/m113gavin.html
http://en.wikipedia.org/wiki/M113_ar...sonnel_carrier

You might try Tanknet, where active and former tankcrew have devoted pages upon pages debunking this myth.

Originally Posted by Phaelen Bleux

Some sources state the M113A3 has an NBC system; this would require the vehicle to be Sealed.

It isn't.

Cheers

HANS