Max range display is the guaranteed (worst-case headwind) full-tank range (ISS-099, v0.51.0)

2026-09-22 08:57:09 +00:00
parent f01c3f417c
commit 8319b2fa78
7 changed files with 69 additions and 13 deletions
@@ -137,3 +137,16 @@ export function maxRangeKm(burnPerKm: number, emptyWeightKg: number, maxFuel: nu
  const rho = FUEL_DENSITY_KG_PER_L;
  return Math.log(1 + (rho * maxFuel) / emptyWeightKg) * ((emptyWeightKg + rho * maxFuel) / (rho * burnPerKm));
 }
+
+// Max headwind burn multiplier over the weather domain (v0.51.0, ISS-099): the upper end of
+// windBurnFactor's [0.8, 1.2] range — a full 30 kt headwind (the max in lib/weather.ts) ÷ 150.
+export const MAX_WIND_BURN_FACTOR = 1 + 30 / 150;
+
+// Guaranteed full-tank range (v0.51.0, ISS-099): the maxRangeKm closed form under worst-case
+// headwind burn — any leg within this distance is flyable in ALL weather, since windBurnFactor
+// never exceeds MAX_WIND_BURN_FACTOR and requiredFuelFor grows with the burn rate. This is what
+// the UI displays as "Max range", so a spec-possible leg always passes flyPlane's fuel guard
+// (requiredFuelFor ≤ maxFuel under the same wind-adjusted burn).
+export function guaranteedRangeKm(burnPerKm: number, emptyWeightKg: number, maxFuel: number): number {
+  return maxRangeKm(burnPerKm * MAX_WIND_BURN_FACTOR, emptyWeightKg, maxFuel);
+}