Afterburner
What it is
Afterburner is a stat-category artifact that procs on a repeating internal timer. Each proc grants the ship two simultaneous timed buffs — a flat additive boost to fire-rate percentage and a percent-multiplicative boost to max speed — for a short window. Within the timer-driven offensive-burst family it is the only artifact that pairs an offensive fire-rate swing with a mobility swing on the same clock, making it both a damage cooldown and a movement cooldown sharing a single timer.
Identity
| Field | Value |
|---|---|
| Display name | Afterburner |
| Category | stat |
| Icon | racing car |
| Damage tag | none (type-agnostic) |
| Trigger type | timer |
| Trigger repeats | yes |
| Banner on proc | yes |
| Proc audio cue | none defined |
| Primary color | ff8800 |
| Secondary color | cc5500 |
| Bright color | ffbb44 |
The trigger is a self-repeating timer keyed off the tier’s interval value. There is no kill-streak condition, no damage-type gate, and no other entry condition beyond the timer firing.
Per-tier values
Tiers indexed 0 → 3 map to uncommon → rare → epic → legendary. A fifth common tier is prepended at runtime via the engine’s flat-bonus layer and shares the uncommon values record.
| Tier | Rarity | Proc interval (s) | Buff duration (s) | Fire-rate bonus (%) | Speed bonus (×) |
|---|---|---|---|---|---|
| 0 | Uncommon | 12 | 5 | 40 | 0.25 |
| 1 | Rare | 11 | 5 | 60 | 0.35 |
| 2 | Epic | 10 | 6 | 85 | 0.50 |
| 3 | Legendary | 8 | 6 | 120 | 0.70 |
The proc interval shortens, the buff duration lengthens at the epic step, and both the fire-rate bonus and the speed bonus scale with tier. At legendary the buff is active for 6 out of every 8 seconds — three-quarters of run uptime.
The (duration / interval) uptime ratio across tiers is 5/12, 5/11, 6/10, 6/8.
Effect
On every timer tick, the artifact fires two stat-modifier actions in the same frame plus a VFX burst and a flash on the artifact icon.
| Element | Value |
|---|---|
| Stat 1 modified | fire rate (percent) |
| Stat 1 mode | flat additive percentage |
| Stat 1 source tag | artifact:heat_racer:rate |
| Stat 2 modified | max speed |
| Stat 2 mode | percent multiplier |
| Stat 2 source tag | artifact:heat_racer:speed |
| Buff window (both stats) | tier-defined buff duration |
| VFX type | burst-and-ring |
| VFX particle count | 24 |
| VFX scale | 5.0 |
| VFX lifetime (s) | 0.40 |
| VFX color | ffbb44 |
The fire-rate buff is applied to the ship’s fire-rate percentage stat as a flat additive percentage for the buff duration. The speed buff is applied to the ship’s max-speed stat as a percent multiplier (the speed-bonus value is the multiplier delta — e.g. legendary’s 0.70 multiplies max speed by ×1.70) for the same buff duration. Both buffs share the same duration, the same source artifact, and the same start frame, but are tracked as two independent sources on the stat layer.
Stacking rules
| Rule | Value |
|---|---|
| Stacking mode (both buffs) | refresh |
| Max stacks (both buffs) | 1 |
Neither buff can accumulate. A second proc landing while the first window is still active resets the remaining duration on both buffs to the full tier-defined window without adding a second stack. Because both buffs share a single source artifact and a single trigger, they always start and end on the same frame.
When the proc interval is greater than the buff duration (tiers 0 and 1 — 12/5 and 11/5) the buffs lapse between procs and the ship spends part of the cycle unboosted. When the proc interval approaches the buff duration (tier 3 — 8/6) the buffs chain with only a short gap. Tier 2 (10/6) sits between these regimes.
Afterburner does not share its trigger source with any other artifact; it has its own dedicated timer keyed off the artifact’s own interval. Other timer-trigger artifacts run on their own independent timers. Tier upgrades replace the per-tier values record wholesale. Tier is set at run start by meta-progression and does not change mid-run.
Summary
Afterburner is a timer-driven dual-buff artifact: every 12 / 11 / 10 / 8 seconds it grants a paired fire-rate-percent and max-speed-multiplier buff for 5 / 5 / 6 / 6 seconds. Refresh stacking with max stacks = 1 on both buffs, banner and VFX on proc, no kill-streak or damage-type gate. Uptime ratio climbs from 5/12 at uncommon to 6/8 at legendary.
EXTRACT-CANDIDATE flags
- Timer trigger primitive. The
trigger: { type: 'timer', timerDuration: '$interval', timerRepeat: true }shape is a generic effect-engine primitive used by any artifact with a self-clocked proc. Same flag as Slipstream. Belongs on aconcepts/effect-engine-triggers.mdpage rather than repeated per artifact. - Refresh stacking with max stacks = 1. Recurring buff-stacking mode across the stat-burst artifact family. Same flag as Frenzy / Aegis / Bloodlust / Salvager / Slipstream. Candidate concept page:
concepts/buff-stacking-modes.md. - Multi-action proc with shared duration. Two
modify_statactions sharing one$durationtoken but distinct source tags is a reusable pattern for any artifact that buffs multiple stats together. Same flag as Slipstream. Candidate concept page or roll-up section: paired buffs with independent stat-layer tracking. - Mixed-mode stat actions in one proc. Afterburner fires one
flatand onepercentmodifier action in the same frame against two different ship stats. The interaction of these two modes on the stat layer (additive flat vs multiplicative percent) is engine-side and belongs on aconcepts/stat-modifier-modes.mdpage. - Common-tier flat-bonus layer. The runtime adds a 5th common tier that shares the uncommon values record and differentiates only through a per-artifact flat-bonus field. Afterburner declares no
flatBonus, so common-tier behavior depends on engine defaults. Document once on the artifacts roll-up. - Fire-rate stat composition. How the
fireRatePctship stat composes with other sources, base fire rate, and per-weapon overrides is not specified in the artifact file and belongs on a combat / weapon-pipeline page. - Max-speed stat composition. How the
maxSpeedship stat composes with base ship speed, other multipliers, and movement-input ceilings is not specified in the artifact file and belongs on a ship-movement or combat-pipeline page. - Banner, flash, and VFX actions.
showBanner: true,flash_artifact, and theburst_and_ringVFX recipe are shared UI/VFX primitives across many artifacts; their exact behavior is engine-side and should live on the artifacts roll-up or a VFX-primitives page. - Uptime ratio as a design lever. The (duration / interval) ratio progression across tiers (5/12 → 5/11 → 6/10 → 6/8) is a deliberate design curve and is a candidate for the artifacts roll-up’s tier-scaling discussion, not a per-entity prose paragraph.
- Timer-driven dual-buff family. Afterburner and Slipstream are both self-clocked dual-buff procs with refresh stacking. The family relationship (and any third sibling) belongs on the artifacts roll-up or a
concepts/timer-driven-burst-artifacts.mdpage rather than repeated per entity.