Yaw geometry
Yaw Mark Radius Calculator
Convert a measured chord and middle ordinate into the radius used by a critical-speed calculation.
Method overview
radius = chord² ÷ (8 × middle ordinate) + middle ordinate ÷ 2
A longer chord generally reduces the proportional effect of small measurement errors, but only when the selected points follow a consistent curved mark.
Evidence to document
- Chord endpoints on the same identifiable tire mark.
- Middle ordinate measured perpendicular to the chord.
- Several measurement sets where the mark permits.
- A diagram showing the exact field points used.
Limitations
Radius geometry does not prove that the mark is a critical-speed yaw. Mark classification and tire-force evidence come first.
Record measurements, assumptions, units, rounding, and source material so another investigator can reproduce the result. See the methodology and validation center for verification policy and citation guidance.
Related tools
Critical speed yaw · Lambourn multi-point method · Choose a tool