Vehicles: 3E vs. 4E

[lugaid]

It gets worse when I look around, as the PzIV front hull armor is listed at Wikipedia at 80mm (3.1"), which is confirmed by the Tank Museum. That would give a DR217 at DR70 per inch. Which neither WWII (DR315) nor High-Tech (DR280) come even close to.

So, the High-Tech number can't have come from adjusting to real-world data. It has to be a conversion from the WWII number by multiplying by 0.9 (where WWII got its number is probably a mystery lost to the ages at this point).

The Sherman is at least closer, as the Tank Encyclopedia lists its front hull armor at 76mm/3", which tracks with the DR210, even if that is precisely 0.7 of the WWII value. However, it notes that the armor on the M4A1 is 30mm/1.18" elsewhere (I'm not counting the turrets here), which would convert to DR82.6, very far from the DR105 of the actual case in High-Tech, and still wouldn't help us in knowing where WWII got its numbers. This is still more evidence that High-Tech simply converted from the existing WWII stats, since the numbers for anything that isn't front hull match up too precisely, if probably erroneously due to applying the slope adjustment where there is no slope in the WWII design.

This is getting very far out in the weeds, though, as I'm not really concerned (in my particular case) with converting historical WWII vehicles from 3E sourcebooks to 4E, but rather in whether the design system in WWII/VE itself will produce suitable results for 4E. Can I simply take DR numbers from WWII/VE and apply them usefully as 4E vehicles? If, as you say, 1" of RHA is DR70 in both 3E and 4E, then it would seem that yes, this seems reasonable as an appropriate approximation given the lack of a 4E vehicle design system (which I am not asking for; that discussion is past and resolved in favor of keeping GURPS alive and producing new books that will sell). It will give me reasonably useful numbers for counterhistorical vehicles that I can then, after getting an idea of how they should look in 4E terms, make more freeform estimates without going through a full design process. That is, once I've designed a few diesel-powered mecha or whatever, I'll have a better idea of what they should look like given the appropriate tech assumptions and can then have a baseline around which to just spit out some numbers that look right enough.

[lugaid]

Originally Posted by Fred Brackin

That this is the Cheap armor in WWII is a problem. It's not the Cheap metal armor for TL6 in Ve2. That is something available at TL4.

It's not, though? The armor on the Tank Chassis, as I've noted, costs 4.5× as much as armor on Wheeled Chassis. It's the VE armor rated at 0.5, which at TL6 is "expensive" armor.

[Fred Brackin]

Originally Posted by lugaid

It gets worse when I look around, as the PzIV front hull armor is listed at Wikipedia at 80mm (3.1"), which is confirmed by the Tank Museum. That would give a DR217 at DR70 per inch. .

Your statement would be true _if_ the Panzer IV (and every other tank in WWII) was armored with the very specific grade or armor steel known as Rolled Homogenous Alloy. I do not assume that to be true and would not plan on deriving DR values from thickness alone.

I feel as though I must reiterate that no numbers used in HT were convetrted from Ve2 or any other source from earlier editions and that specifically High Tech is about real things from the real world. That's where its' numbers come from..

[lugaid]

And the WWII "expensive" Tank Chassis armor works out to a VE value of 0.4, which is "advanced" at TL6.

[Fred Brackin]

Originally Posted by lugaid

It's not, though? r.

<shrug> The WWII corebook on p.142 in the textbox labelled "Vehicles variance" specifies that the armor listed as "Cheap" in the WWII book was supposed to have DR70 per inch. That's the number for RHA.

[lugaid]

Originally Posted by Fred Brackin

Your statement would be true _if_ the Panzer IV (and every other tank in WWII) was armored with the very specific grade or armor steel known as Rolled Homogenous Alloy. I do not assume that to be true and would not plan on deriving DR values from thickness alone.

If that were the case, then there would be no value in the DR70 per inch factor you have presented, since it would seem that we should just ignore it in almost every case anyway to fit more subjective evaluations. It fits exactly one real-world measurement on the two tanks that existed contemporaneously which we're discussing, using the values in High-Tech. The front armor on the PzIV is only 4mm thicker than the Sherman, yet the DR, for subjective reasons I suppose, is rated at fully 133% of the US tank's in High-Tech.

I feel as though I must reiterate that no numbers used in HT were convetrted from Ve2 or any other source from earlier editions and that specifically High Tech is about real things from the real world. That's where its' numbers come from..

But that doesn't seem to follow from any real-world values (excepting solely the front hull armor of the M4A1) I have been able to find on these two tanks. The M4A1's front hull armor comes out to DR210 (coincidentally, I guess, exactly 0.7× the value in WWII, just as the side armor is also exactly 0.7× the WWII value, even though the real-world numbers would imply a much lower value of DR82.6 on the sides, or call it DR80 after rounding—I guess that the side armor was produced in a subjectively much more advanced facility than the front hull armor, being better than 125% as effective as the hull front armor using the High-Tech numbers). The PzIV values are even less grounded in real-world numbers, as shown (for example, the front hull 80mm armor should, at DR70 per inch, come to DR220, making its High-Tech DR280 around 127% as effective as the RHA factor), but match very closely in all cases with a factor of 0.9× the WWII values.

That is, you say that the data in High-Tech was derived independently, but the circumstantial evidence points to some very round multipliers that also don't match the real-world data very well.

I suppose, in the end and for my purposes, the numbers in WWII's design system (and, by extension, VE) are close enough to something accurate that they can serve without serious adjustments. The variations between vehicle designs in WWII and vehicle stats in High-Tech seem to be arbitrary and mostly unrelated to the real-world numbers anyway, but the underlying assumptions seem to follow consistent values that can approximate real-world numbers. Sure, Pulver has adjusted his formulas for power to weight ratios and vehicle speeds or whatever, but we are not getting those and I am not asking for those, even if they were used for some vehicle stats in High-Tech (or not). I just want some reasonable numbers to fudge up some diesel-powered walking armored vehicles that aren't too out of line with diesel-powered tanks, gasoline-powered cars, or high-performance, aviation-gas-fuelled aeroplanes. Now that I know that there's hardly any resemblance between real-world numbers for armor related to actual vehicle designs in either WWII or High-Tech, I guess I just don't need to worry about it. Might make some notes to use DR220 for the PzIV front armor and DR80 for the Sherman and PzIV sides, though.

[lugaid]

Originally Posted by Fred Brackin

<shrug> The WWII corebook on p.142 in the textbox labelled "Vehicles variance" specifies that the armor listed as "Cheap" in the WWII book was supposed to have DR70 per inch. That's the number for RHA.

Those terms aren't used anywhere else in the design system, except that Tank Chassis have the option for "expensive" armor that matches up with the VE "TL6 advanced" armor. I'm going to guess that they're left over from an earlier draft. You did mention that the playtest was rushed.

[Fred Brackin]

Originally Posted by lugaid

If that were the case, then there would be no value in the DR70 per inch factor you have presented,

The standard wasn't created for statting up WWII tanks. RHA is a common material for measuring penetration of both projectiles and explosive warheads. It's like saying there are 12 inches in a foot. It doesn't become useless because some people's feet are longer or shorter.

[Fred Brackin]

Originally Posted by lugaid

Is. Sure, Pulver has adjusted his formulas for power to weight ratios and vehicle speeds or whatever, but we are not getting those and I am not asking for those, even if they were used for some vehicle stats in High-Tech (or not).

Will you please accept that the number in HT do not come from Ve2 formulas either hidden or not? I'm as close as you're going to come for a source who doesn't work for SJGames.

Coincidence between the two sources is only proof that the Ve2 formulas were reverse-engineered from real world vehicle data.

[lugaid]

On the other hand, that note in WWII on p.142 does seem to indicate where the WWII numbers come from, since 3" of "expensive" armor (DR98 per inch) by that measure comes out to about DR294, close to DR300, giving us the M4A1 rating, and 3.15" (the real-world measure for the PzIV) comes out to DR308, close enough to DR315 I suppose, especially if bumping it up by the same small amount as the Sherman. But that makes the High-Tech numbers seem even more arbitrary.