Wind-adjusted fuel burn ±20% + refuel-for-flight buys 150% margin (ISS-070, ISS-071, v0.36.0)

2026-09-21 08:47:42 +00:00
parent 6d8e1ad35e
commit 5030fcd8b4
16 changed files with 309 additions and 81 deletions
@@ -119,6 +119,15 @@ export function requiredFuelFor(
  return (emptyWeightKg / rho) * (Math.exp(k * rho * distanceKm) - 1);
 }

+// Wind adjustment to per-km burn (v0.36.0, ISS-070): the headwind component of a wind blowing
+// FROM `windDirDeg` against a leg heading `bearingDeg`, as a multiplier on burnPerKm —
+// factor = 1 + headwindKt/150, exactly [0.8, 1.2] over the weather range 2–30 kt (±20%).
+// Pure; callers apply it as burnPerKm * factor so every call site agrees on one value per leg.
+export function windBurnFactor(windKt: number, windDirDeg: number, bearingDeg: number): number {
+  const headwindKt = windKt * Math.cos(((bearingDeg - windDirDeg) * Math.PI) / 180);
+  return 1 + headwindKt / 150;
+}
+
 // Max range from a FULL tank under the weighted model — solve requiredFuelFor(d) = maxFuel for d:
 //   (We/ρ)(e^{kρd} − 1) = F  →  d = ln(1 + ρF/We) · (We + ρF)/(ρ·burnPerKm).
 // Returns raw km (call sites round); zero fuel gives exactly 0. Pure — display-only, the sim