Project Njord — Wind & Flight-Time Visualizer

Wind bands

Polar easterlies (60°–90°)

Mid-lat westerlies (30°–60°)

Tropical easterlies (0°–30°)

drag to rotate · scroll to zoom · click a city to reroute

Route

Departure (A)

Arrival (B)

Cruising speed 460 kt

Flight times

A → B — —

B → A — —

wind asymmetry: —

Route geometry

Distance—

Δ longitude—

Geodesic apex—

Apex threshold—

n_Trop—

V (norm)—

Ground speed along route A → B

Departure click to flip direction Landing

EFT_asym breakdown

Wind intensity vs latitude

Peak at ~45° (the jet stream) and a smaller peak near ~75°. The PDF models this as a signed coefficient: positive near the equator (trade winds oppose eastbound flights), negative in mid-latitudes (westerlies help them).

How to read this

The Njord formula uses a single number — EFT_asym — to capture the net wind effect along the great-circle route. It depends on Δlongitude, the latitude of the route, and whether the path climbs above both airports into the jet-stream band. The correction is divided by V², so slow aircraft feel wind effects more strongly. Flight times shown are estimates from method 3 of the PDF (no empirical data blend).