Vehicle Maker Tanks

[Timerover51]

I decided to take a look at Vehicle Maker when it comes to a Real World Tank. The basic parameters for Vehicle Maker tanks appear to be as follows.

A Tank has a crew equal to its tonnage divided by 2.

Install TWO weapons: one Vehicle-Mount and one Turret-Mount.

If I understand it correctly, Tracked Vehicles are Tech Level 7, and add 2 Tons to the Vehicle Design Box. As this will be Fossil-Fueled, it looks like I subtract 2 from the Tech Level and add another 2 tons to the Vehicle Design Box. As I am seeing how a Light Tank stacks up, it looks like I subtract 1 from the Tech Level, divided the Vehicle Design Box tonnage by 2, and add +1 to speed. It also looks like Armor is divided by 2, dropping it to 25 from 50.

Now, in the example of fitting a tank to the Vehicle Design Box on 257, the hull and turret are treated separately, so I will do likewise.

If I am not reading something correctly, anyone can feel free to correct me.

The Real World Tank that I am looking at is the US M3 Stuart Light Tank from World War 2. All data comes from US Army Technical manuals.

The hull of the M3 is approximately 4.5 meters long by 1.5 meters high by 2.24 meters wide, so 3 squares X 1 square X 2 squares giving 6 cubes or 1.5 tons. The turret is less than a meter high at about 0.91 meters, and about 1.5 meters in diameter, so another cube is added, for a total of 7. Initial estimate is therefore 7 cubes or 1.75 tons. As the M3 was tracked, I add 2 tons, and powered by either 80 octane gasoline or 50 cetane Diesel, both Fossil Fuels, so I add another 2 tons, for a total of 5.75 tons, but as it is a Light Tank, I divide by 2 to get 2.875 tons. The actual cube of the vehicle was 924 feet or 26.164766 cubic meters, or less than 2 Traveller displacement tons, but still 2.875 tons is fairly close.

Now, based on the 2.875 tons, the crew should be 1.4375 persons, dividing 2.875 tons by 2. I am not sure if that means that the crew should be 1 or 2, but rounding up appears to make the most sense, so per Vehicle Maker, the crew should be 2. The actual crew of the tank was 4. Based on the French experience with 2 man tanks in World War 2, at least for that period, 2 man tanks were a not a good idea. So not very good there.

Now, the armament of the M3 was as follows: one 37MM gun and a co-axial .30 caliber air-cooled Browning in the turret, one .30 Browning in the hull front, two .30 Brownings fixed in the side sponsons, and a flexible .30 Browning mounted on the turret roof for the commander to use against air and ground targets. I am not sure how that compares to the two weapons cited earlier. By the way, it gets a lot worse with the M3 Grant/Lee Medium when it comes to weapons.

The speed of the Vehicle Maker tank looks like it is 4 + 1 or 5, which equates to 50 kilometers per hour or 31 miles per hour. The maximum allowed speed of the M3 with governor was 36 miles per hour, so not that far off.

The armor per Vehicle Maker is 25, but looking at the Enhancers, it looks like Fossil Fuel reduces it by another 10, down to 15. Per page 640, one centimeter of steel, quality not stated, is equal to an Armor Value of 70. Dividing 15 by 70 gives me a value of 0.21428571 centimeters, or 2.14 millimeters, or less than a tenth of an inch of steel.

The thinnest armor on the M3 was located on the top and bottom 0.375 inches, or 9.525 millimeters, just under a centimeter. The thickest armor on the M3 hull was 1.5 inches sloped for greater resistance, while the turret front was 1.5 inches with the sides and rear having 1.25 inches. That equates to 3.81 centimeters and 3.175 centimeters, without allowing for any hull slope. Plugging those figures into the Armor Value for steel of 70, the thinnest armor on the M3 should have an Armor Value of 66, while the thickest armor on the M3 should have a rating of 267. The Armor Values for Vehicle Maker are way, way, way off. That without plugging in any difference in protection between mild steel and rolled or cast homogeneous steel, or face-hardened or high-hardness plate.

Side Note: The armor penetration of the US .30 caliber round at 100 yards was 0.625 inches or 1.5875 centimeters, or an Armor Value of 111. The US .50 AP round penetrated an inch of armor at 300 yards, or 2.54 centimeters, or an Armor Value of 177.8. It could penetrate, assuming a 90 degree impact, a half-inch of homogenous armor plate at 1,000 yards. Against mild steel, that would double.

Given that Iron, presumably Wrought Iron, is given an Armor Value of 50 for a one centimeter thickness, while Steel is given a value of 70 for the same thickness, it looks like the Steel is Mild Steel, and not any form of actual steel armor. The standard Figure of Merit for Wrought Iron in comparison to Mild Steel is 1.3, which would make give Steel an Armor Value of 65 in comparison to the Value of 50 for Iron.

Edit Note: It looks like Highways are disallowed terrain for Tracked Vehicles. The M3 Light Tank operated very nicely on highways prior to and during World War 2, using rubber-blocked tracks. The same holds true for trails. Steel tanks treads will tear up roads pretty bad if asphalt, but that does not make them unsafe to drive on.

I am not sure why there is no Desert Terrain in the Terrain Chart.

 

[Reban]

I'm not clear on whether you're following the Fillform or the Freeform route here. It actually looks like you're doing a combination of the two which is a little confused.

If I follow the same steps using Rob's VehicleMaker App to speed things up I get:

code       type                                         TL  q  vol spd   ld  AV: ca, fp, rp, sp, ps, in, se   KCr  
---------- -------------------------------------------- -- -- ---- --- ---- ---- --- --- --- --- --- --- -- ------ 
ELTT       Enclosed Fossil Lt Tracked Tank               3  0  5.5   3   -1   19  10  14  10  14   0  32 20    700

The need to specify Enclosed is something that really annoys me as it has a TL-1 penalty. Without that the Tank would be TL4 and Av15, but by your figures it should be the average Av167.

There might be a way to approach it by starting with a tracked military vehicle or car.

The crewing issue definetly breaks down for small "Tanks", likewise on larger grav tanks like canon 12ton vehicles the crew calculation gives a crew of 6 compared to a canonical crew of 3, but thats explainable as driver, commander, gunner, plus three jump seats.

 

[Timerover51]

I'm not clear on whether you're following the Fillform or the Freeform route here. It actually looks like you're doing a combination of the two which is a little confused.

If I follow the same steps using Rob's VehicleMaker App to speed things up I get:

code       type                                         TL  q  vol spd   ld  AV: ca, fp, rp, sp, ps, in, se   KCr  
---------- -------------------------------------------- -- -- ---- --- ---- ---- --- --- --- --- --- --- -- ------ 
ELTT       Enclosed Fossil Lt Tracked Tank               3  0  5.5   3   -1   19  10  14  10  14   0  32 20    700

The need to specify Enclosed is something that really annoys me as it has a TL-1 penalty. Without that the Tank would be TL4 and Av15, but by your figures it should be the average Av167.

There might be a way to approach it by starting with a tracked military vehicle or car.

The crewing issue definetly breaks down for small "Tanks", likewise on larger grav tanks like canon 12ton vehicles the crew calculation gives a crew of 6 compared to a canonical crew of 3, but thats explainable as driver, commander, gunner, plus three jump seats.

You cannot build a Tech Level 3 Light Tank. It requires an internal combustion engine. The Armor Ratings given are ridiculous when compared to Real World Vehicles. As for the Tech Level adjustments, those are better not discussed.

If you want to find out how to design an Armored Vehicle, I would suggest you track down a copy of Richard M. Ogorkiewicz Design and Development of Fighting Vehicles or Armoured Foces. I have hard copies of both.

 

[David Johansen]

So, on to playing with Vehicle Maker for a light ground car and a TL-8 tank. Is it just me or do the numbers come out a lot better if you apply the Bulk modifiers across the board instead of in order?

Doing so puts my light ground car at 0.5t instead of 0t. With an improved heavy tracked, tank it would be 16t instead of 17t.

I do think care must be taken to remember that we're talking about displacement volume rather than mass when discussing vehicle maker.

 

[Timerover51]

So, on to playing with Vehicle Maker for a light ground car and a TL-8 tank. Is it just me or do the numbers come out a lot better if you apply the Bulk modifiers across the board instead of in order?

Doing so puts my light ground car at 0.5t instead of 0t. With an improved heavy tracked, tank it would be 16t instead of 17t.

I do think care must be taken to remember that we're talking about displacement volume rather than mass when discussing vehicle maker.

That is one of the odd things in Vehicle Maker. A designer worries about cubic volume when the vehicle has to be shipped somewhere, and even then, that is a secondary issue. When it comes to armored vehicles, the issues are:

1. Horsepower to weight ratio: This along with the suspension system dictates the vehicle's agility and movement. Under 10 to 1, you have a slow-moving vehicle that needs armor to compensate for speed. Over 15 to 1, you are in a much more survivable vehicle, and in conjunction with a good suspension system, you should have good cross-country mobility.

2. Cross-country mobility is dependent not only on horsepower, but ground pressure per square inch of track. A high ground pressure makes for a vehicle that bogs down easily, low ground pressure boosts your battlefield mobility.

3. How much of a trade off are you going to make between armor, firepower, your horsepower to weight ratio, and your ground pressure. Is your suspension capable of high cross-country speeds? What sort of terrain with most of your operations take place in?

All of that is dependent on mass, forget volume. But mass never factors into the design process. Volume is a factor in watercraft design, but not ground vehicle design.

 

[robject]

Compare against GunMaker guns to find the problem areas. A tank should handily shrug off machine gun fire, combat rifles, etc, but perhaps be less effective against antitank guns. So for example, a TL6 light tank is protected against Machine Gun fire with Ar 25.

 

[Timerover51]

Compare against GunMaker guns to find the problem areas. A tank should handily shrug off machine gun fire, combat rifles, etc, but perhaps be less effective against antitank guns. So for example, a TL6 light tank is protected against Machine Gun fire with Ar 25.

I prefer using actual armor penetration against realistic armor values and totally ignoring whatever Gun Maker says about them, along with viewing the Armor values on page 640 of T5.0.9 with total and complete disbelief.

One thing that I am curious about, since I have your attention, is whether or not an armored vehicle is limited to only one or two weapons.

NoteT. Install TWO weapons: one Vehicle-Mount and one Turret-Mount.
NoteC. Install ONE turret mount weapon.
NoteV. Install ONE fixed mount weapon (supercedes NoteT or NoteC)., page 258, T5.0.9.

How is a fixed mount weapon defined? Does it mean a weapon on a limited traverse mount, as it seems to imply?

What is the greatest mass of a weapon that can be mounted on a vehicle of any type?

 

[Timerover51]

One thing that I am curious about, since I have your attention, is whether or not an armored vehicle is limited to only one or two weapons.

Quote:
NoteT. Install TWO weapons: one Vehicle-Mount and one Turret-Mount.
NoteC. Install ONE turret mount weapon.
NoteV. Install ONE fixed mount weapon (supercedes NoteT or NoteC)., page 258, T5.0.9.

How is a fixed mount weapon defined? Does it mean a weapon on a limited traverse mount, as it seems to imply?

What is the greatest mass of a weapon that can be mounted on a vehicle of any type?

I never did get these questions answered, and I am still curious about them.

 

[David Johansen]

The lower right corner of page 217 discusses portability. It's woefully inadequate if you don't apply modifiers for light and heavy vehicles to it. There's some precedent for that in the multipliers for Titan sized armor. I never got around to doing titan mount comparisons but that might work to get guns that will actually penetrate armor.

The table goes

20 - 200 Crewed
200 - 500 Turret
500 - 1000 Vehicle
1000 - 100000 Fixed

How that's supposed to integrate with vehicles is still, at best, fuzzy, I hope Marc is aware of the issue by now.

Anyhow, as to realistic vehicle comparisons, T5 paints with a broad brush and approximates. Much as I love Fire Fusion and Steel or GURPS Vehicles I can still appreciate the functionality of the T5 system.

It's an internal combustion powered light tank, what's its armor, range, speed, and cargo.

Over thinking it beyond that is futile.

 

[kilemall]

The Striker example tank was the German WWII Panther. I'd be interested in seeing a comparison example.

A bit disappointing to read, but for many people that might do just fine for the sort of thin-skinned APCing they will do most of the time.

The same comments I make about HG ship design re: doctrine, economics and opposing forces apply here- hard to say how a design would pan out without knowing what the other guys are doing and what the combat biome the vehicle is to operate in is about.