Main Content

Incidence & Airspeed

Calculate incidence and airspeed

  • Incidence & Airspeed block

Libraries:
Aerospace Blockset / Flight Parameters

Description

The Incidence & Airspeed block supports the 3DoF equations of motion model by calculating the angle between the velocity vector and the body, and also the total airspeed from the velocity components in the body-fixed coordinate frame.

α=atan(wu)V=u2+w2

Note

  • For fixed-wing aircraft, the angle, α, computed by the Incidence & Airspeed block 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. Incidence & Airspeed 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 block for analysis of VTOL configurations is not recommended. As an alternative, use the 6DOF Wind (Quaternion) or 6DOF Wind (Wind Angles) blocks, which provide α and β as outputs.

Examples

Ports

Input

expand all

Velocity of the body, specified as a two-element vector, resolved into the body-fixed coordinate frame.

Data Types: double

Output

expand all

Incidence angle, returned as a scalar, in radians.

Data Types: double

Airspeed of the body, returned as a scalar.

Data Types: double

References

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

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced before R2006a