Omakase Amzn

Sunday, October 27, 2013

Fuel Houserules for RPGs (and Chainsaws!)

Ok, I saw a question about how to track fuel and ammo and similar things in an RPG, and I actually like these kinds of questions, so first here is a Yahoo Answer I came across, which suggests a number of approaches (

Now for me, If you take one of the last answers, that a pint of premixed fuels (good luck if you decide to focus on details enough that chainsaws need oil and gas both) gives him about 15 minutes of constant cutting for his chainsaw (though he doesn't say what cc or rpm), you might need to know:

- "gas tank" size: 0.25 - 3 pints
- rpm: 2400 min idling - 12000 max full power
- cc: 30-120
- hp: 2-10
- max running/cutting time: 10-15 minutes per pint
- lbs: 10-25
- bar length: 12-60" (larger exist but aren't single-person practical)

From the above data I gathered, it looks like it would be possible to have a couple different sizes of chainsaws, from a small home utility to a much more powerful full-sized professional carbide saw.

Given the general ranges of gas tank sizes, I would probably suggest an easy breakdown for "ammo" for a chainsaw would be 10-30 minutes of full power per tank, and probably not use fuel "unit" sizes smaller than 1/4 pint, with most chainsaw tanks being 0.5-3 pints.

Averaging all this, I'd say, gives you "fuel/ammo" ratings of 1 (1/4 pint or 1/2 cup) to 12 (3 pints) "shots" per tank, at 2 minutes per "unit" (1/4 pint), or a total of 24 minutes worth of use per tank, if it held 3 pints (12 units).

For game-practical purposes, if a round is 6 seconds and 10 rounds is a minute, I'd say you might "round down" to make it harder for chainsaws to be the common weapon, reducing the fuel efficiency suggested above - maybe the fuel is older, the mix is bad or old most commonly, and using the saw for full power and active cutting will use more fuel than the ideal minutes-per-tank rating, which is for idling, so probably:

And for completeness, "realods" or "clips" might be containers as follows:

1 gallon = 3.79-4 liters (or quarts) = 8 pints = 16 cups = 128 oz = 4000 ml/cc (32 fuel units)
1 quart/liter = 2 pints = 4 cups = 32 oz = 950-1000 ml/cc (8 fuel units and 16 minutes)
1 pint = 2 cups = 16 oz = 473 ml/cc (4 fuel units and 8 minutes)
3/4 pint = 1.5 cup = 12 oz = 356 ml/cc (3 fuel units and 6 minutes)
1/2 pint = 1 cup = 8 oz = 236 ml/cc (2 fuel units and 4 minutes)
1/4 pint = 1/2 cup = 4 oz = 120 ml/cc (1 fuel unit and 2 minutes)

1 round (6 seconds) = 1/4 fuel unit (1/16 pint) and 30 seconds used
4 rounds (24 seconds) = 1 fuel unit (1/4 pint) and 2 minutes used
6 rounds (36 seconds) = 1.5 fuel units (5/16 pint) and 3 minutes used
8 rounds (48-54 minutes) = 2 fuel units (1/2 pint) and 4 minutes used
10 rounds (1 minute) = 2.5 fuel units (3/4 pint) and 5 minutes used
12 rounds (72 seconds) = 3 fuel units (1 pint) and 6 minutes used

So a 6 round combat uses 1.5 fuel units and/or 3 minutes, a 10 round one is 2.5 fuel units and uses 5 minutes, etc.

I have changed it a bit to bring it more in line with the more important aspect, which is how those unit sizes fit in with combat and game mechanics, so I'd recommend:

1 fuel unit = 1/4 pint = 2 minutes or 20 rounds of full power or active cutting

This allows you to have various chainsaw types, with idling speeds (for keeping it at the ready but not expending any more precious fuel than necessary), being equal to full-power minutes x3 (if you want to use idling speeds at all).

The above highlighted formula would allow a single fuel unit to carry a PC through 20 rounds of combat (depending on the game system, this may be a lot of rounds) from start to finish, which is what just feels like a "just barely enough" amount of fuel, which will allow players to make use of fueled devices, without relying on them extensively. Obviously, "fuel" can be virtually anything you want, including batteries or energy cells, vortex plasma for futuristic weapons or devices, or whatever else.

Small Home Chainsaw: Capacity 1 (0.25 pint), Minutes/Tank: 6 (idling) or 2 (full power)

Medium Utility Chainsaw: Capacity 8 (2 pints), Minutes/Tank: 48 (idling) or 16 (full)

WorldChewer: Capacity 12 (3 pints), Minutes/Tank: 60 (idling) or 20 (full)

A creative GM or game designer could work these ratings into possibly differing damage ratings (full power = x, idling = 1/2 x) or take this idea any number of ways! This same method could work for vehicles, with a certain number of Fuel Units allowing a vehicle to travel a certain distance, then requiring the PCs to gather more fuel when that runs out, usually important in post-apocalyptic and/or zombie games.


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