Aviation
Crosswind component
Wind speed and angle off the runway against crosswind.
Readings
Drag the red line, or type into any two boxes — the third is solved. The marked box is the one being solved for.
Print at 100% scale, then check the 100 mm bar with a rule before trusting a reading.
Why this one is an instrument
The angle scale is a sine scale, which compresses hard above sixty degrees — the geometric statement of the old rule that anything past about sixty is effectively full crosswind. Reading it off a curve you can see beats remembering a table of thirds, and it degrades gracefully: even a rough straightedge gives an answer good enough to make a decision on.
- Equation
- X = W · sin θ
- Ranges
- W 5–60 kt · θ 10–90 °
- Reading
- Any two values fix the third. Outside the printed ranges the instrument stops being valid — that is what the end marks are for.
These are drawn from the stated equation and nothing else. Where an equation is itself an approximation — hyperfocal distance and tap drill sizes both are — the instrument inherits that approximation exactly, no better and no worse.