The Best That Never Was 2 (Prototypes)

[Legbreaker]

The armour values seem a bit high on some of them though if they were only ever supposed to protect against small arms and shrapnel. There's modern IFVs with less (mainly Soviet).
How'd you arrive at those values?

[ArmySGT.]

XM800T with Chrysler ITV turret.




XM800T with conventional Hispano Suiza 20mm and M60D

[pmulcahy11b]

Originally Posted by ArmySGT.

XM800T with Chrysler ITV turret.

Demands to be statted! Already doing the research.

[Rockwolf66]

Originally Posted by pmulcahy11b

Demands to be statted! Already doing the research.

Not much to be found unfortunatly.

Crew: 3 (Commander, Driver, Gunner)

Armor: unknown, Possibly similar to an Early M2 Bradley,

Weapons Systems:
Main Turret
Hispano Suiza 20mm with Unknown amount of ammo
M60D with Unknown amount of ammo

Alternate Turret
twin TOW launchers.

Mobility level was similar to the M113.


Video of third surviving prototype

[Rockwolf66]

Originally Posted by Rockwolf66

Not much to be found unfortunatly.

Crew: 3 (Commander, Driver, Gunner)

Armor: unknown, Possibly similar to an Early M2 Bradley,

Weapons Systems:
Main Turret
Hispano Suiza 20mm with Unknown amount of ammo
M60D with Unknown amount of ammo

Alternate Turret
twin TOW launchers.

Mobility level was similar to the M113.


Video of third surviving prototype

I've just found that the 20mm had 500 rounds of ammunition and the M60 had 2,000 rounds of ammunition for it.

[nuke11]

Details of the XM800T ARSV

You have to dig around in your library of Jane's Armored Fighting Vehicle Guides from around 1976 to get the details of this.

The XM242 25 mm Chaingun was being developed to be fitted to the winner of the ARSV competition either the tracked or the wheeled. The test vehicles mounted the M139 20 mm autocannon.

Crew: 3
Weight Loaded: 8618 kg
Weight Empty: 7980 kg
Length: 4.673 m
Width: 3.438 m
Height Turret: 2.399 m
Height Hull: 1.663 m
Ground Clearance: 40.6 cm
Track Width: 0.482 m
Length of Track on Ground: 2.743 m
Ground Pressure: 0.32 kg/cm2
Maximum Road Speed: 88.5 km/h
Maximum Cross Country Speed: 25 km/h
Maximum Water Speed: 7.2 km/h
Acceleration 0-48 km/h: 10 seconds
Range: 725 km
Fuel: 397 liters
Amphibious: Yes
Gradient: 60%
Side Slope: 40%
Vertical Obstacle: 0.762 m
Trench: 1.828 m
Engine: GM 6V53 AT Diesel
Armament: M139 20 mm Cannon, M60D LMG
Ammunition: 500 rds 20 mm, 2000 rds 7.62 mm

[Draq]

I hope Paul is taking notes. He is the one who inspired this thread.

[unkated]

Originally Posted by ArmySGT.

XM800T with conventional Hispano Suiza 20mm and M60D

In the bottom picture of the XM800T (see above), is that an IR Spotlight on the right of the turret?

Uncle Ted

[StainlessSteelCynic]

The XM800 project was developed for the reconnaissance role but from what little info I could find specifically about the XM800T, it also had the ability to designate targets for other vehicles/aircraft so I think it's probably the surveillance/target designator sight.

[unkated]

Originally Posted by StainlessSteelCynic

The XM800 project was developed for the reconnaissance role but from what little info I could find specifically about the XM800T, it also had the ability to designate targets for other vehicles/aircraft so I think it's probably the surveillance/target designator sight.

Hmm I though that was developed in the late 80s; the XM800T was developed in the mid-1970s. Did we have that capability then?

Uncle Ted

[StainlessSteelCynic]

Originally Posted by unkated

Hmm I though that was developed in the late 80s; the XM800T was developed in the mid-1970s. Did we have that capability then?

Uncle Ted

In regards to Precision Guidance, The knowledge itself is quite old, both the Germans and USA were using precision guided weapons in the later years of WW2 and although these were radio-controlled, the technology advanced quite quickly with the US developing an infra-red homing missile for anti-ship use in 1945.
Laser guided weapons were developed in the 1960s with the US making use of them and other PGMs from 1972 (specifically during the Vietnam War).

[ArmySGT.]

Originally Posted by unkated

In the bottom picture of the XM800T (see above), is that an IR Spotlight on the right of the turret?

Uncle Ted

I don't really know... From the appearance I can only guess......

Appears to me to be either a thermal imager or a low light tv system.

[dragoon500ly]

Supposed to have been a low light tv...

[nuke11]

Originally Posted by ArmySGT.

I don't really know... From the appearance I can only guess......

Appears to me to be either a thermal imager or a low light tv system.

That is the day/night sight. It was developed by Delco Electronics Division of General Motors. It has high and low power day channels and high and low power night channels.

[unkated]

I found most of the data from a Blog describing the XM800T's development...

The M-139 was a licensed copy of the French HS.820 20mm autocannon, used in aircraft and AAA. When Oerlikon bought Hispano-Suiza, they replaced their current 20mm design with it. The US used it only for a/c, where it was equipped with 2x 75-rd magazines. (This weapon, while excellent, saw little US use, as we developed the rotary M61 cannon and put that on aircraft.)

Anyway, see the attached...

[Draq]

Xm-734. One of the developmental evolutions of the m113 leading to the Bradley. I find it fascinating.

[unkated]

Originally Posted by Legbreaker

The armour values seem a bit high on some of them though if they were only ever supposed to protect against small arms and shrapnel. There's modern IFVs with less (mainly Soviet).
How'd you arrive at those values?

Fair question. I will explain below.

1. Thank you for making me take another look. You made me spot an error. I have a table of co-efficients used for adding an effect for different armor types (explained below). I had added a entry to the table, but had not udpated the table's definition to include an additional row; "Steel Riveted" stopped being within the defined table; Steel riveted (less effective plates of steel riveted together) was being picked up as the stronger "Steel" (basic steel armor, 1940 to 1955)

After correcting the table, a soem of the armor values changed; 5s becoming 4s, some 4s becoming 3s.

2. How does Uncle Ted make armor sausage?

I built a spreadsheet (of course). The armor section works like this. I had collected a raft of data for WW2 and post-WW2 military vehicles for Advanced Tobruk, including armor (detailed to facings and slope of armor). Using that analysis, i compared those sheets to some of the existing older vehicles in the T2K cannon (which is, not surprisingly, inconsistent, even with specific time periods)

What I came up with was that for steel armor:
for WW2 steel armor (1940 - 1955ish) = an armor point for every 7mm;
for more modern steel armors, one for every 5mm

Modern armor/5
Older armor/7

This is complicated by average slope of the given armor face, which may drive increase the value of by up to a factor of 2.

This is complicated by the armor type. For vehicles in the period of steel armor (basically, every tank before 1975, and several since), this breaks down into solid or welded armor and bolted (bolted includes most armored vehicles built before 1940).

Remember that coefficient I mentioned above? This is where armor type gets factored in. These vehicles are mostly all endowed with bolted armor plates.
(exceptions: VK-31 & A2E1 Medium Mk I have steel)

Now, T2K uses one armor scale for vehicle vs Vehicle and personnel combat, which leads to a few peculiarities at the bottom o f the scale. Using the scale outlined above, many of these early tanks would have an armor factor of 2, which would not keep out contemporary small arms (Lee-Enfield rifle, 8mm Mauser, Lebel etc).

So I include a check to provide "design for effect" - if I have armor values and the process above gives an armor value of less than 3.6, it adds 1. This ensures that these early vehicles can shake off small arms.

Modern MBTs (and some recent IFVs), where they seldom mention armor thickness directly, and their armor type is not steel are handled differently.

Corrected version attached

And now I have some other files I need to correct.....

Uncle Ted

[Legbreaker]

With the early tanks, the crew would often be injured from spalling when rifle and machinegun bullets hit the armour near them - the reason spall liners are basically standard equipment in AFVs today.
Have you modelled that somehow?

[ArmySGT.]

Standard Manufacturing Excalibur 20mm Vulcan SHORAD

[ArmySGT.]

Standard Manufacturing Rough Terrain variable height transporter.

[unkated]

Originally Posted by Legbreaker

With the early tanks, the crew would often be injured from spalling when rifle and machinegun bullets hit the armour near them - the reason spall liners are basically standard equipment in AFVs today.
Have you modelled that somehow?

Nope. None of the versions of T2K have it modeled in vehicle combat, and T2K includes HEAT which creates spalling.

I wanted to have vehicles to compare to existing ones in T2K, not re-invent the combat system, particularly where at the moment I don't contemplate actually using these designs in a game. But i'll bear that in mind for if an when I consider using these vehicles.

Uncle Ted

[Legbreaker]

Pretty much any projectile which hits has the potential to cause spalling - the thicker the armour, the larger the impact or explosion needs to be though. For more modern vehicles spalling is not much of an issue as they're almost invariably fitted with spall liners.
For early AFVs (up to the late 1930's and into the 40's I believe) spall liners where not standard and from what I can find were really only developed in response to the introduction of HESH rounds by the British in the 1940's.
In WWI, AFV crews had to wear armoured masks similar to the one pictured to protect the face and especially eyes from flying shrapnel spalled off the inside of their vehicles armour. Even just the impact of ordinary rifle bullets could be enough to blind a crewman close to the point of impact (a gunner for example looking for targets).

While this is not an issue for T2K era vehicles, probably not even the left over WWII ones (which were likely retrofitted with liners) it is probably something which should be kept in mind if an earlier vehicle was used.

Attachment 3711

[Draq]

Ok, so there have been plenty of vehicles designed and tested over the years, and the best is not always chosen, for various reasons. What vehicles do you guys think should have been adopted instead of the ones the military picked?

[CDAT]

Originally Posted by Draq

Ok, so there have been plenty of vehicles designed and tested over the years, and the best is not always chosen, for various reasons. What vehicles do you guys think should have been adopted instead of the ones the military picked?

I would have liked to see the prototype Abrams with 25mm coax. Once you up-gunned to the 120mm having a coax that can take out the light armor would have been nice.