Editing Slip angle (section)

{{Short description|Term or maneuver in vehicle dynamics}}
{{about|car handling|the topic in aviation|Slip (aerodynamics)}}
{{More citations needed|date=June 2018}}
[[File:TreadDeflected1.jpg|thumb|350px|'Deflected' tread path, sideslip velocity and slip angle]] <!-- image size is specified to make text legible -->
[[File:Tire Sip Angle.png|thumb|350px|Graph of cornering force vs slip angle]] <!-- image size is specified to make text legible -->
[[File:Tire coordinate system.png|thumb|350px|A coordinate system used for tire analysis by Pacejka and Cossalter. The origin is at the intersection of three planes: the wheel midplane, the ground plane, and a vertical plane aligned with the axle (not pictured). The x-axis is in the ground plane and the midplane and is oriented forward, approximately in the direction of travel; the y-axis is also in the ground plane and rotated 90º clockwise from the x-axis when viewed from above; and the z-axis is normal to the ground plane and downward from the origin. Slip angle <math>\alpha</math> and [[camber angle]] <math>\gamma</math> are also shown.]] <!-- image size is specified to make text legible -->
In [[vehicle dynamics]], '''slip angle'''<ref name="Pacejka">{{cite book
| title = Tire and Vehicle Dynamics
| last = Pacejka
| first = Hans B.
| edition = Second
| publisher = Society of Automotive Engineers
| year = 2006
| isbn = 0-7680-1702-5
| pages = 3, 612}}</ref> or '''sideslip angle'''<ref name="Cossalter">{{cite book
| title = Motorcycle Dynamics
| edition = Second
| last = Cossalter
| first = Vittore
| publisher = Lulu.com
| year = 2006
| isbn = 978-1-4303-0861-4
| pages = 47, 111}}</ref> is the angle between the direction in which a wheel is pointing and the direction in which it is actually traveling (i.e., the angle between the forward velocity vector <math>v_x</math> and the vector sum of wheel forward velocity <math>v_x</math> and lateral velocity <math>v_y</math>, as defined in the image to the right).<ref name="Pacejka" /><ref name="clark71">{{cite book |last1=Clark |first1=S.K. |title=Mechanics of Pneumatic Tires |date=1971 |publisher=NHTSA |edition=1st |url=https://books.google.com/books?id=rREQRVg7meMC |access-date=26 February 2023}}</ref> This slip angle results in a force, the [[cornering force]], which is in the plane of the [[contact patch]] and perpendicular to the intersection of the contact patch and the midplane of the wheel.<ref name="Pacejka" /> This cornering force increases approximately linearly for the first few degrees of slip angle, then increases non-linearly to a maximum before beginning to decrease.<ref name="Pacejka" />

The slip angle, <math>\alpha</math> is defined as <br /><math display="block">\alpha \triangleq -\arctan\left(\frac{v_y}{|v_x|}\right)</math>