Send me your vehicle data!

Hi! I’m the guy who is tuning up the vehicle code.

One of my current projects is to revamp the acceleration/top speed model, so that it has a recognizable relation to reality. See https://github.com/CleverRaven/Cataclysm-DDA/issues/25652 for the details, but it’s a bit coding and physics heavy.

The important bit is that light vehicles with small engines should go faster, and medium and heavy vehicles with big engines should have their top speeds reduced A LOT (no more tanks with a theoretical top speed of mach 3!). But ideally, no existing vehicle should have it’s safe speed unacceptably: if your deathmobile currently has a safe speed of 200mph and you drive at 70 mph, the new safe speed shouldn’t be 35 mph but it might be 60 mph.

I only have vehicle data for the game’s standard vehicles. I think my approach looks good for them. But I’d like to know about other people’s vehicles.

If you can send me the following data about your CDDA vehicle, that would be much appreciated:
Vehicle name
Mass (in lbs or kgs, I don’t care, just tell me which)
Number of engines, types of engines, and number and types of alternators
Number and size of wheels.
The width in tiles of the vehicle. If you have wing mirrors or other protrusions sticking out the side, give me both numbers.
The length in tiles of the vehicle, and how much of that is full boards or quarterboards or open frames, and how much has a roof.
The vehicle’s current safe and top speeds, and the speed you normally drive it, and what you would consider the minimum acceptable speed for long distance travel in that vehicle. (again, kph or mph, I don’t care, just tell me).

Basically, I want this data:
Mark’s car
1250 kg
2 Enhanced Electric Engines, no alternators
4 32" armored tires
4 tiles wide, 5 with the wing mirror
5 tiles long, with half-boards front and back, and windshields and doors in the middle
cruise speed 608 kph, max speed 1723 mph, but I drive at 120 kph and could tolerate 100 kph.

Thanks! If you provide this data, I will crunch it and try to make sure that when I change the game code, I don’t make your vehicle unacceptably slow.

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I’ll try to dig up my old run with the “Jeep-C-V” and see if I can’t get you that data then. Be aware in reality the vehicle makes almost no sense so I don’t know what it will do for your numbers.

Also do I need to update the old save to the latest experimental?

I haven’t changed anything yet, so no need to update.

And I’m not super concerned if the vehicle makes no sense. You built it in the current game, I shouldn’t break it casually. Though if you’re trying to power a 130 ton monstrosity with a pair of 10 HP electric motors because you don’t mind traveling at 16 mph, then I might break your vehicle. But if you’re trying to power your 130 ton monstrosity with 4 V12 engines and you can currently make 30 mph, I am going to try to respect that.

Then my data might not be super helpful. It’s just a Humber with a wooden caravan bolted to the back, two solar arrays, an additional electric engine, and some bike pedals.

IIRC I could still make 9-10mph with the pedals despite them also having two alternators. So that should probably rightfully get broken.

I’d be curious to hear how you’re modeling that stuff.

There’s a bunch of things like:

  • Weight should have a bigger effect on efficiency (currently doesn’t feel like it)
  • More tires should improve handling and traction (esp on bad surfaces), but tend to hamper efficiency and top speed.
  • Particularly heavy vehicles should need more minimum wheels. Having a 10t vehicle running on 4 basic car tires pretty much shouldn’t work - they should be badly damaged by trying to run heavily overloaded. 20t vehicles should need some SERIOUS tires or treads to operate, especially off-road.
  • Wider vehicles should generally be more stable, but slower and less efficient.
  • Engines feel way overpowered in most cases, regardless of whether they are efficient or not - it would be nice to have more choices in terms of engines that specialize in acceleration vs efficiency vs top speed.

I’ll try to post my current APC stats when I get home this evening.

Technically the ground pressure of a 130tn vehicle is really problematic. You need a huge baseline with very wide treads or a shitload of tires to keep it from just basically sinking into the dirt - or even cracking pavement outright.

They tried making some tanks up in the 180tn range in WWII - they didn’t really work out. Too massive and slow, they basically couldn’t use bridges or rail at all, they would effectively destroy any road they operated on, and they were impossible to maintain or recover if they suffered any kind of drive or tread failure, as there were no recovery vehicles remotely large enough to service them. That’s before we even get into issues with fuel efficiency. :sweat_smile:

EDIT: Vehicle Data
DeathMobile MkI
Constructed from initial APC Frame.
Safe/Top Spd: 239/643 KPH
Acc: 21km/h/t
Mass: 11474kg (11.5mt)
Cargo Volume: 2982L
Tires:

  • 24" steering tires (x2)
  • 24" running tires (x4)

Engine: Enhanced Electric Motor (x1)
Power:

  • Standard Solor Panels (x17)
  • Vortex Generator (x1) <- I don’t know if this even does anything
  • Mini-reactor (x1) (used rarely - the solar panels are just enough to keep the minifridge running with enough left over for recharging tools and a modest amount of road travel)
  • Storage Batteries (x5)

10x5 footprint, including forward ram plate.
Full Heavy Frame, all outer tiles military Composite armor, Fully roofed.

I rarely accelerate over 80kph. I’m in no particular hurry and try to keep speeds moderate to conserve battery power.

Okay, here we go. (Keep in mind that this is back from April, things might have changed).

RoseRide
20 tonnes
1 enhanced electric engine
6 tires of i don’t remember what diameter, but it’s the basic for an RV
5 tiles wide hull + 1 tile on each side with mirrors and external tanks outside
16 tiles long (1 tile rams, 1 tile half boards, 1 tile windshield, 1 tile doors, then boards all the way to the end, except for the last 2 tiles, which are empty (frame+cargo carriers)) (also 11th row is a back wall of boards and the door in the middle)
safe 185 km/h; max 643 km/h, absurdly high speeds, considering quite poor acceleration.
usually not worth driving faster than 100 km/h.

Can upload a screenshot if needed

I would really prefer to discuss the implementation in the github issue, but briefly:

  • Drive force at the wheel is engine power / speed
  • Drag force is roughly 1/2 Cair * air density * cross sectional area * speed^2
    That’s just the standard formula for air drag force. Cair depends on the vehicle shape, but it’s roughly 0.3 for streamlined sports cars, 0.4-0.6 for most cars, and 1 or so for motorcycles and tanks.

A vehicle’s maximum speed happens when drive force is the same as drag force, so maximum speed is the cube root of (1/2 * Cair * air density * cross sectional area).
Wide vehicles or tall vehicles have more cross sectional area, and are slower for the same engine than shorter or narrower vehicles.

Anyway, there’s more detail and discussion on the github issue.

Murderizer (I don’t remember naming it this and it’s neat you all get to judge me for it!)
16593 lbs
1 enhanced electric motor, no alternators
4 24" wide wheel
5 tiles wide, no mirrors
10 tiles long including the ram, boards on sides and back, There’s a line of quarterpanels ahead of the windshield (see screenshot)
Heavyduty doors on sides at ', shutters in mid and back ’
Safe/top speed = 158/400 mph, but I mostly drive between 10 and 50 mph depending on the light. I just don’t drive all that fast.
Murderizer

This is my mid-range vehicle, not really a deathmobile yet. Point A to point B.

I also use a motorcycle in earlygame/for short distances. It’s basically just a frame with wheels, though, so I figured you probably don’t care about that.

I care about all vehicles. Small vehicles are interesting too.

If you’re running a recent experimental with the mainline Vehicle Additions mod, the vortex generator is now a perpetual motion machine that produces electricity without consuming fuel. Your engine consumes a maximum of 40000 epower per turn, a vortex generator always produces 37300 epower per turn. Turn it on and crank up the speed.

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35mph is actually the norm in the New England area mate. 60mph is considered highway normal. 70+…you must be thinking of california xD

2500lbs car is also pretty normal and most other larger vehicles round here are trucks. 2 seater with a suicide in the back for fold out seat and space for your redneck stuff. Flatbed in back and nobody drives a toyota unless it was tricked out for racing…no…really. Not full of Tokyo Drift or anything. But the asian masses around here do like that stuff enough, that it is a thing. A nice thing(not racist >;P)

edit:

One more thing. The road ways area often really tight. I dunno if this is a part of what you are doing or maybe Kevin can adjust this to match. Just mentioning that the city streets are usually very old. Some are still cobble in less maintained towns(think horse and buggy days, brick laid by hand). The game uses road ways which are a few tiles to wide. The only wide road ways would be highways.

Right, well, motorcycle, then.

Name: Putter
723 lb
1 4.0L V6 gasoline engine, one car alternator
2 17" wheels
1 tile wide
3 tiles long, no boards/quarterpanels. Just a roof over the seat.
Safe/Top speed: 154/316 mph – I rarely drive it more than 40 off-road, but on long stretches of pavement I’ll push it to around 90.

No picture this time. It’s basically just

0  - tire
# - seat, controls, roof, all the important bits
H - tire/trunk

I made it a code block because it kept turning the hash symbol into weird giant letters.

I build some vehicles and width seems to influence top speed the most. I drive vehicles as big as the RV or smalller. On roads at day light I do 140/160 kmh. When I do know the road I hit max save speed often. 200/250 Kmh is still driveble mostly due the good breaks you have when using the handbrake. Accelaration is what you stop from driving at mach 1 in the current game

Heres one of my special vehicles i build a while ago.

No solar cells installed nor needed.

https://www.youtube.com/watch?v=zR6SN5FT90w 12 x V12 Test Drive.

https://www.youtube.com/watch?v=3l4GwM6bLPM 8 x V12 on a bike.

Here is a light vehicle that I originally built in version 7128 (the most recent build I used it in is 7847).

I named it the Loot Scooter.

Its purpose was to transport me from home base to an area that I wanted to loot and then transport me and my loot back to base.

It is 3 tiles by 3 tiles (at widest). The layout is this:

123
. 4 (Ignore the period, leading spaces keep being ignored)
567

tiles 1 & 3 = frame, 17" wheel (steerable)
tile 2 = frame, headlight, large electric motor
tile 4 = frame, clock, 5-point harness, controls, seat, swappable storage battery case, storage battery.
tiles 5 & 7 = frame, 17" wheel
tile 6 = frame, solar panel, cargo space

I had a small one-man dune buggy in mind when I designed it. My mental image of it has a roll cage built with pipes around the seat, but I could not build that part in the game.

Stats are:

Safe/Top Speed: 182/320 mph
Acceleration: 17 mph/t
Mass: 1090 lbs

How fast I drive depends on obstacles but when I can I run 80 to 100 mph. I could live with 60 mph if I had too.

Small vehicles are mostly getting a boost, though you’ve already got a large engine on a small vehicle so you’re getting a downgrade. Still, current estimated cruise speed is 120 mph.

Are gearboxes coming anytime soon? Or ever?

This thing has appeared in the majority of my games for day-to-day use. I play with a static base and this thing is what I use to collect the parts for the larger deathmobile that i’ll use for longer hauls. The death mobile tends to change based on what I find but this my baby.

I need wheel count and size and acceptable vehicle speed, please.

I need wheel count and size and acceptable vehicle speed, please.

7x1 + ram. (occasionally i’ll cut one frame)
x2 wide wheels
Speed is 305/472 km/h unloaded. IIRC it will still do 150+ loaded but I rarely drive more than ~120 km/h or so for fear of crashing.