Glider Polar Visualiser

I built this as a way to explore how polar curves shift with ballast and different MacCready value.

The app fetches polar data directly from XCSoar’s codebase. It parses the struct definitions using regex, then fits a quadratic curve through the three measured data points using a Cramer’s rule regression.

From there it applies MacCready theory: given a thermal strength setting, it calculates the optimum inter-thermal cruise speed, the effective cross-country speed, and marks the tangent point on the polar. Ballast adjusts the polar by scaling the wing loading, which shifts the whole curve right and down as you’d expect.

Supports multiple unit types and allows users to overlay two gliders in order to compare their performance.

Test it properly by clicking here.