Skypirates! Development Log #2: RPG Layer

At the very bottom, Skypirates!1 is an RPG. World entities like characters and airplanes have rollable attributes, and those determine how they interact. Those interactions are out of scope today, though. We’re going to cover how the RPG layer works at its very core: the dice, or at least the simulated dice.

If you’ve been around a very long time, or spent a long time trawling the archives, you might have come across a set of rules for building zeppelins in Savage Worlds. This was the jumping-off point. Skypirates designs past used a step dice system Savage Worlds players would have found very familiar. Start at d2, and skills/vehicle characteristics go up to d12 by die size, then to d12+d2 and d12+d4.

That last clause indicates the problem: step dice have poor resolution. For a moment-in-time, quick-playing tabletop RPG, it’s sufficient. For a PC game where I expect the timeline to run from about 1922 to 1937, it doesn’t leave a lot of room for multiple generations of airplane, in a period of time wherein aviation technology would advance even more quickly than in reality owing to greater conflict between the major powers. It leaves even less room for variation in individual airframes2. So, regrettably, step dice had to go, simple as they are to reason about.

In abandoning physical dice as the underlying abstraction, I found myself wondering, “Why not a 1-100 system?” A number between 1 and 100 represents each skill or characteristic. To roll it, generate a random number between 1 and the skill value. Highest number wins. Hard to do with physical dice, trivial with computers.

It doesn’t quite capture everything, though, so I brought in an idea familiar to players of D&D Modern: advantage. Roll two dice, take the better result. But, I don’t plan on using it primarily for rolling character skills with a bonus. Instead, in a form I’m calling ‘capped advantage’, it’s a way to combine pilot skill with airplane characteristics.

Say a plane has Agility 50 and its pilot has Flying 70. I take that to mean that the pilot knows where the edge is, and can use every bit of the plane’s agility. So, behind the scenes, we roll Flying with capped advantage Agility: roll both skills, and take the better of the two, up to a cap of the best Agility result. If the rolls are Agility 37 and Flying 64, the pilot has hit the cap, and the final result is 503.

I’ll go into the representation of planes and characters at some later date, but I wanted to make sure we got through the week with some content here, even if it’s not the allegedly-weekly news update.


  1. While the exclamation mark is part of my official branding plan, I am likely to omit it in the running text for reasons of forgetfulness. 
  2. The Secret Horsepower Race relates a story of six production Spitfires, which varied in tested top speed from 330 mph to 360 mph. 
  3. I plan on doing something similar with aerial gunnery: roll the gun’s accuracy with capped advantage the pilot’s Gunnery skill. For simulation-fun reasons, lighter guns are more inherently accurate, but that doesn’t mean a pilot can shoot better than his overall skill just because the gun helps. 

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