Vehicle Stats: A Discussion

[TheSkywise]

I am in need of designing vehicles for my 1920s Bureau 13 Horror Campaign. Players are secret govt agents with modified vehicles. Since VDS for 4e hasn't come out yet, I am hoping for some assistance with designing vehicle. Since I am sure I am not the only one looking for help, this post will hopefully help others as well.

Some of the stats are defined as to how to obtain, others are described. I am using the following references:

B462: Beginning of Vehicle Stats and rules.
B558: HP and DR of stuff
HT228: More vehicle info

Here is my interpretation of the stats:

ST/HP: Pretty easy. Mass of vehicle. Both ST and HP are the same. If unpowered, there is no ST score. Formula: 4 x (Cube Root of Empty Weight in lbs) [B558]

Hnd/SR: Handling and Stability Rating. Handling is the skill roll modifier and Stability is the margin of failure allowed without a "major problem." All well and good, but these stats are not defined by formula to my knowledge and must be eyeballed. Anyone have any ideas on this one?

HT: Vehicle's health. The letter code is pretty self-explanatory, but how do you determine the HT number? Any guidelines? Looks like the range in GURPs Basic/High Tech is 9 to 12, but how do you figure this out?

Move: Pretty Easy. First number is acceleration in yards per second and the second is top speed in yards per second. Formula: MPH x 0.4889 gives yards per second (or simply divide MPH by 2 for quick and dirty).

LWt: Should be pretty easy. Simply try to find the vehicle's Loaded weight in tons from a reference. Of course, what would be a good source for this? Are there any conversions for other similar vehicular terms (and what are the terms)? Anyone with clarification or suggestions on how to obtain this value?

Load: Also should be pretty easy. Simply the cargo (including passengers) that can be carried in Tons.

SM: Pretty Easy. This is the size modifier. Simply take the longest dimension of the vehicle, and use this number to determine the size modifier from the table on page B19. For example, I found on the internet the stats for a 2009 GMC Canyon Trucks 2WD Crew Cab (similar to my own truck). It shows a listing of 193.4 inches in length, which in turn is 5.75 yards. This would make the Size Modifier a +3 on the table.

Occ: Pretty easy. Simply the number of occupants a vehicle can carry. Can indicate passengers/crew and accommodations. No formula needed.

DR: The vehicle's damage resistance. I have a little difficulty figuring out this one. According to HT236, a Ford V-8 has a DR of 8. I am trying to use the tables on B558-9, but still can't figure a formula or method to determine this. Any help would be great.

Range: Pretty easy. How far a vehicle can travel on a full tank. Simply take the average MPG and multiply by the fuel tank capacity. My GMC gets 18 MPG (City) with a fuel tank holding 19 gallons. Thus, it has a range of 342 miles (18 x 19). Of course, if I used the Highway MPG rating of 24 MPG, I get 456. Which one should I use? I think the highway would be more accurate since the only time you would use this stat is for those long journeys.

Cost: Pretty easy. Simply figure out the cost based on references. Doesn't really have a "set in stone" formula, other than to convert it to GURPs Dollars. For example, in my 1920s campaign, I convert 1920s Dollars to GURPs Dollars by multiplying the 1920s $ by 10 (or dividing the GURPs Dollars by 10).

Locations: Pretty easy. Count the windows, figure out if it has tracks, etc... and look up the letter code. This one doesn't really need much explanation.

Draft (Watercraft): Pretty easy. Simply the minimum depth a boat can operate in. NOTE: Unlike most stats, this is listed in FEET.

Stall (Aircraft): Minimum airspeed (yards/second) needed to stay airborne, takeoff, and/or land.

Notes: Used for special info regarding vehicle.

Okay, that is my understanding of vehicle stats. Any assistance would be great. Especially for determining Hnd/SR, HT, etc...

EDIT: Please top your reply with which stat your talking about such as DR, etc.

[Sam Baughn]

Originally Posted by TheSkywise

SM: Pretty Easy. This is the size modifier. Simply take the longest dimension of the vehicle, and use this number to determine the size modifier from the table on page B19. For example, I found on the internet the stats for a 2009 GMC Canyon Trucks 2WD Crew Cab (similar to my own truck). It shows a listing of 193.4 inches in length, which in turn is 5.75 yards. This would make the Size Modifier a +3 on the table.

Take a look at B550; most ground vehicles have a Size Modifier one larger than their length would suggest.

[TheSkywise]

Perfect Organism, your correct. According to B550, "Elongated boxes, like most ground vehicles, add +1 [to SM]" Thus, my GMC's SM should be +4 instead of +3. Thanks for the help!

[Collective_Restraint]

I had started a project a while ago to convert all automobiles available in North America (it's available on my site), even though I never actually finished, there are quite a few available. I posted the details of the conversions in this thread. Hope it helps.

[TheSkywise]

Collective Restraint, yes, I have been to your site several times before. I love your site, and applaud your work. However, even you had to eyeball certain stats (HT, Hnd/SR, etc). I want to try and figure out how to determine the actual values. Surely, there is some reason certain values were what they are. I want to figure out why. I am open to discussion.

[Crakkerjakk]

My criteria for HT has always been "how often does it break down." If you have access to consumer reports, any of their mechanical reliability criterion should give you a rough guideline for HT, with the average being 10, 9 and 11 as error-prone or -free, and 12 for seriously heavy duty military stuff with multiply redundant or over-engineered components. Frex, I'd give toyota tacomas a HT of 11. Hummers would probably also be 11, as they're military (+1 HT from average) but not the super-expensive overdesigned type of stuff HT 12 is made of. I'd probably save HT 12 for the Warthog.

[sir_pudding]

Originally Posted by TheSkywise

Hnd/SR: Handling and Stability Rating. Handling is the skill roll modifier and Stability is the margin of failure allowed without a "major problem." All well and good, but these stats are not defined by formula to my knowledge and must be eyeballed. Anyone have any ideas on this one?

You have to do this one by comparison. If a vehicle has a reputation for maneuverability give it a +1 or +2 to handling compared to other vehicles in it's class (or a -1 or -2 if it's steers like a cow). Stability is usually going to be pretty consistent within a class.

HT: Vehicle's health. The letter code is pretty self-explanatory, but how do you determine the HT number? Any guidelines? Looks like the range in GURPs Basic/High Tech is 9 to 12, but how do you figure this out?

Most vehicles will have HT 10. If it has a reputation as an unreliable clunker give it a 9, if it's especially rugged it should get an 11, legendarily tough (the IL-2 Shturmoviks of the world) should get a 12.

LWt: Should be pretty easy. Simply try to find the vehicle's Loaded weight in tons from a reference. Of course, what would be a good source for this? Are there any conversions for other similar vehicular terms (and what are the terms)? Anyone with clarification or suggestions on how to obtain this value?

This really depends on the vehicle. Commercial vehicle weights are usually pretty easy to obtain. Military vehicles can be found in sources like the Jane's books (which are usually available from public libraries) or websites like Globalsecurity.org. Wikipedia is a usually a good start, and will often link to good primary sources.

DR: The vehicle's damage resistance. I have a little difficulty figuring out this one. According to HT236, a Ford V-8 has a DR of 8. I am trying to use the tables on B558-9, but still can't figure a formula or method to determine this. Any help would be great.

For commercial vehicles this is almost always going to be the same as every other vehicle in it's class.
For military vehicles: 1 inch of RHA=DR 70. Also a vehicle is often described in terms of the weapons it's protected against; in that case give it enough DR on it's most protected sides to stop the average damage (1d=3.5).

Range: Pretty easy. How far a vehicle can travel on a full tank. Simply take the average MPG and multiply by the fuel tank capacity. My GMC gets 18 MPG (City) with a fuel tank holding 19 gallons. Thus, it has a range of 342 miles (18 x 19). Of course, if I used the Highway MPG rating of 24 MPG, I get 456. Which one should I use? I think the highway would be more accurate since the only time you would use this stat is for those long journeys.

EPA rated MPGs for commercial automobiles in the US are famously inaccurate. You might want to look for 3rd party reviews (like Car & Driver), instead.

[Anthony]

Originally Posted by TheSkywise

Move: Pretty Easy. First number is acceleration in yards per second and the second is top speed in yards per second. Formula: MPH x 0.4889 gives yards per second (or simply divide MPH by 2 for quick and dirty).

Actually, not easy at all, and completely impossible for most vehicles, as they don't have constant acceleration. For example, consider a car that can go 0-60 in 10 seconds. That's 6 mph/sec, so move should be 3, right? Except, well, that same care can likely go from 0-30 in 3 seconds (acceleration 5) and from 60 mph would probably take 3-4 seconds to reach 70 mph (acceleration 1.5), so what's its actual speed?

Originally Posted by TheSkywise

SM: Pretty Easy. This is the size modifier. Simply take the longest dimension of the vehicle, and use this number to determine the size modifier from the table on page B19.

Most vehicles are structurally blocky enough to get +1 to effective size modifier.

Originally Posted by TheSkywise

Range: Pretty easy.

Well, it would be if the range statistic actually was 'range at speed X'; vehicle performance varies significantly depending on velocity.