Runway / Wind Calculator

A browser-based aviation tool that visualises wind conditions against your configured runways and calculates headwind and crosswind components in real time.

What it does

• Draws an animated compass rose showing your runways
• Animates wind particles flowing from the reported wind direction
• Highlights the ideal runway for current conditions with a landing-direction airplane silhouette
• Displays headwind/tailwind and crosswind (left/right) components

Useful for any GA pilot who wants a quick sanity check before departure or when listening to the ATIS.

Usage

Enter the reported wind direction (degrees) and wind speed (knots). The rose updates live:

Field	Description
Wind Direction	Meteorological FROM direction, 0–359°
Wind Speed	Knots

Use the − / + stepper buttons to nudge direction by 10° or speed by 1 kt — handy on mobile.

Runways are stored in localStorage so your configuration persists between visits. Hit Reconfigure runways to change them or Reset to restore defaults.

Runway input format

Runways are entered as a comma-separated list of runway numbers (not headings):

09, 27
09,27
09, 27, 14, 32

Development

npm ci           # install dependencies
npm start        # webpack dev server at http://localhost:8080 (live reload)
npm test         # run unit tests (vitest)
npm run build    # production build → ./dist

Requires Node 22+.

Project structure

├── index.html                  # app shell
├── js/
│   ├── app.js                  # canvas rendering and DOM interaction
│   ├── wind-calc.js            # pure calculation functions
│   └── wind-calc.test.js       # unit tests
├── css/
│   └── style.css
├── webpack.common.js
├── webpack.config.dev.js
├── webpack.config.prod.js
└── .github/workflows/
    └── deploy.yml              # CI/CD pipeline

CI/CD

The GitHub Actions workflow in .github/workflows/deploy.yml runs on every push to main and on pull requests:

1. Install — npm ci for a clean, reproducible install
2. Build — npm run build compiles and minifies to ./dist
3. Test — npm test runs the vitest unit test suite
4. Deploy — on push to main only, the ./dist directory is published to GitHub Pages

Pull request runs execute steps 1–3 only (no deploy), so every PR is validated before merge.

How the maths works

Wind components are calculated using vector decomposition:

• Headwind = windSpeed × cos(angle between wind and runway heading)
• Crosswind = windSpeed × sin(angle between wind and runway heading)

A positive headwind value means a true headwind; negative means a tailwind. Crosswind direction (left/right) is determined by the sign of the cross product.

The ideal runway is whichever heading in your configured set minimises crosswind for the current wind direction.