# How to calculate on ground aircraft yaw rate knowing the longitudinal speed and inferred yaw angle

• a generic aircraft is on-ground taxing at 50 feet per second (~15.25 m/s, ~29.5 knots)
• The pilot inferred 20 degrees of yaw

How can I calculate the yaw rate of the aircraft? Do I have enough information to calculate it?

• Welcome to Stack Exchange! I've never heard the term "inferred yaw angle" before; what does that mean? What do you mean by "the pilot inferred 20 degrees of yaw"? Sep 6 '19 at 12:02

Do I have enough information to calculate it?

No.

Yaw rate is $$rad/s$$. You have an angle, $$rad$$ (or degrees), and you have a linear speed, in $$m/s$$.

You cannot obtain a $$rad/s$$ value from these two data points.

You need the time interval over which the change in yaw has been observed.

• Hi Federico, unfortunately I haven't got that time interval but I was wondering if there is a way to estimate it. For example if the aircraft system is considered as an ideal kinematic model then: yaw rate = (longitudinal speed)/(nose gear to COG distance + MG to COG distance) * tan(yaw angle). Sorry I don't know how to write the equation in the correct forum format! Sep 6 '19 at 12:37
• @AlexMcfly Hi. no, also in that case you would be missing variables, in particular the nose wheel deflection. and if you would like to be precise, the friction coefficient of the wheel with the ground, at a minimum.
– Federico
Sep 6 '19 at 13:21