Incidence, Sideslip, & Airspeed

Calculate incidence, sideslip, and airspeed

• Library:

• Aerospace Blockset / Flight Parameters

• 

Description

The Incidence, Sideslip, & Airspeed block calculates the angles between the velocity vector and the body, and also the total airspeed from the velocity components in the body-fixed coordinate frame. For the equations used in the calculation, see Algorithms.

Ports

Input

Vb — Velocity of body

three-element vector

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

Data Types: double

Output

ɑ — Incidence angle

scalar

Incidence angle, returned as a scalar, in radians.

Data Types: double

β — Sideslip angle

scalar

Sideslip angle, returned as a scalar, in radians.

Data Types: double

V — Airspeed

scalar

Airspeed of the body, returned as a scalar.

Data Types: double

Model Examples

Fly the De Havilland Beaver

How to model the De Havilland Beaver using Simulink® and Aerospace Blockset™ software. It also shows how to use a pilot's joystick to fly the De Havilland Beaver. This model has been color-coded to aid in locating Aerospace Blockset blocks. The red blocks are Aerospace Blockset blocks, the orange blocks are subsystems containing additional Aerospace Blockset blocks, and the white blocks are Simulink blocks.

Open Model

Algorithms

To calculate the angles between the velocity vector and the body, and the total airspeed, the block uses these equations:

$$\alpha ={\tan }^{-1}\left(\frac{w}{u}\right)$$

$$\beta ={\sin }^{-1}\left(\frac{v}{V}\right)={\tan }^{-1}(\frac{v}{\sqrt{u^2+w^2}})$$

The block uses the tan-1 formulation for β to prevent division by 0.

$$V=\sqrt{u^2+v^2+w^2}$$

Extended Capabilities

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

Version History

Introduced before R2006a

R2022b: Updated to Reduce Divide by Zero Issues

The Incidence, Sideslip, & Airspeed block now reduces the potential for divide by zero issues caused by aircraft hovering without forward movement. In previous releases, hovering without forward movement might cause divide by zero issues.