Vehicle Size Modifier

[Henchman99942]

Howdy.

Suppose I wanted a larger or smaller version of a specific type vehicle. Take a preexisting vehicle and increase or decrease it's size a bit. What effect would this have on it's stats? (ST/HP, Move, DR, weight, cost, etc...)

I am not looking for anything as complex a vehicle designing system. I just want to be able to tweek existing vehicle sizes to make new ones that have stats that are 'close enough'. I figure that I will not alter a given vehicle by more than one SM (which is a HUGE size difference if you are talking about doubling the longest dimension.)

And maybe a quick calculation for upping an existing vehicle from TL6 or TL7 to TL8/TL9/TL10. Like, what affect would advanced building materials have on it's weight and other stats, and so on.

Again. I am just looking for a fast fudged calculation... some modifier that I can plug into each of the listed vehicle statistics. There are enough vehicles out there in the various books to fulfill my immediate needs. I just need to be able to upgrade a TL 7 truck to a TL 9 utility vehicle, or a SM +5 TL 9 ATV into a SM+6 TL 9 ATV (These are just examples).

If anyone had already come up quick calculation numbers for this for their own game, but feels that it's scope is too limited or that it isn't accurate enough for use in a supplement, then that is probably exactly what I am looking for.

I really tried looking through the vehicle related threads going back to whenever. I didn't see anything that fitted with this.

[Anthony]

As a rule of thumb, multiply ST, HP, damage, and DR by linear scale (so if you increased length from 20' to 25', multiply by 1.25), multiply cost, weight, cargo/passenger capacity by the cube of linear scale; other stats probably don't meaningfully change if you're only making a small adjustment.

[weby]

SM change:
There is no quick way that is realistic. In reality very few vehicles are "just like the other except larger", things tend to change shape, relative engine power and so on. But you may want to use the spaceships method of scaling as a very rough guide.

Basically increasing SM:
Mass and price are :*3/*10/*30/*100...
Dimensions, DR,ST/HP: +SM on the speed/range table(=*1.5/*2/*3...)
Handling seems to go down by one for each +3 SM. At some point there is a minor increase in stability.
Speed/acceleration do not change in that as your power is equally high compared to the mass...

As for TL:
Changes tend to also be quite much more than just TL change, the actual vehicle often changes in a fundamental way. Things like station wagons being replaced by SUVs and so on.

Also vehicle sizes have changed quite a lot as example, and often in different directions in different parts of the world. Like take the development of the car in the US from the landbarges on 1950s to today, where the normal size of the car plummeted during the oil crisis and has gone up since but is still smaller than then. In Europe the normal size has mostly slowly gone up continuously in that time(with only a very minor change down in the oil crisis).

In short I would really not even try in most cases. In a retrotech setting you could just take the the existing vehicle and increase the price, speed and reliability by some made up number.

[Varyon]

Increasing TL will typically either see more efficient versions of the old tech or outright new tech. Looking at Spaceships, your TL 9 utility vehicle that's based on a TL 7 truck might have a TL 8+ internal combustion engine (for x1.25 endurance), a TL 9 fuel cell (which might give longer or shorter endurance, depending on how much fuel the original truck held, but will be cheaper to refuel), or even a TL 9 fusion reactor (for something like 100 years of endurance, assuming it can be miniaturized to that extent). That's not even accounting for things that aren't in Spaceships, like large batteries (as in the Tesla). Better materials will result in either increased DR or reduced weight (each increase in TL is +1 step on the Size and Speed/Range table to DR; if your original truck had DR 5, the TL 9 one would either have DR 10 or the same DR but the frame would weigh half as much, allowing for more cargo/fuel). There may be other technologies incorporated at higher TL's - your TL 9 vehicle will probably have realtime monitoring of tire pressure, crash avoidance systems, cameras for blind spots, and potentially things like automated driving or a built-in HUD with augmented reality (highlighting potholes, vehicles/pedestrians that might unexpectedly get in your way, and other road hazards).

If you just want a quick-and-dirty conversion, I'd say +1 SSR to endurance (so x1.5, x2, x3, x5, etc) per +1 TL, covering both better efficiency and lower frame weight, will probably work. You'll still probably want to figure out what sorts of gadgets it has built in, however.

As for SM, Anthony has the relationship there. As weby notes, there are liable to be much more substantial changes in design than "like this, but bigger," but Anthony's advice should get you good-enough numbers.