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alphabeta

Compute incidence and sideslip angles

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Syntax

[incidence sideslip] = alphabeta(velocities)

Description

[incidence sideslip] = alphabeta(velocities) computes m incidence and sideslip angles, incidence and sideslip, between the velocity vector, velocities, and the body.

Note

  • For fixed-wing aircraft, the angle, α, computed by the alphabeta function is the angle between the relative wind and the longitudinal axis of the airframe. This angle is denoted in many aerospace engineering references as angle of attack. alphabeta refers to this angle as the incidence angle.

  • In the case of vertical takeoff and landing (VTOL) configurations, the equations used for computation are the same as that for fixed-wing aircraft [1]. However, in maneuvers involving transitions between cruise and hover, there are likely scenarios involving low or zero values of velocity resulting in incorrect incidence and side-slip angles. Therefore, the use of this function for analysis of VTOL configurations is not recommended.

example

Examples

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Open Live Script

Determine the incidence and sideslip angles for velocity for one array. 

[alpha beta] = alphabeta([84.3905  33.7562  10.1269])
alpha = 
0.1194

beta = 
0.3780
Open Live Script

This example shows how to determine the incidence and sideslip angles for velocity for two arrays.

[alpha beta] = alphabeta([50 20 6; 5 0.5 2])
alpha = 2×1

    0.1194
    0.3805


beta = 2×1

    0.3780
    0.0926
Open Live Script
[alpha beta] = alphabeta([84.3905  33.7562  10.1269])
alpha = 
0.1194

beta = 
0.3780
Open Live Script

Determine the incidence and sideslip angles for velocity for two arrays.

[alpha beta] = alphabeta([50 20 6; 5 0.5 2])
alpha = 2×1

    0.1194
    0.3805


beta = 2×1

    0.3780
    0.0926

Input Arguments

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Velocity vector in body axes, specified as an m-by-3 array.

Example: [84.3905 33.7562 10.1269]

Data Types: double

Output Arguments

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Incidence angle, returned as a scalar, in radians.

Sideslip angle, returned as a scalar, in radians.

References

[1] C. Venkatesan, Fundamentals of Helicopter Dynamics: CRC Press, 261. Boca Raton, FL 2015.

Version History

Introduced in R2006b

See Also

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