Subsystem Dimless

Dimless computes the dimensionless rotational velocities pb/2V, qc/V, and rb/2V. Of course, the computation itself is trivial if the elements of the state vector x are known, but since these variables may be needed more than once it is still useful to compute them in a separate block.

Dimless is contained in the subsystem Aerodynamics Group (Beaver) of the Beaver model. Other blocks in that subsystem are: Aeromod (Beaver) and FMdims.

Inputvector: x

  x = [V alpha beta p q r psi theta phi xe ye H]'        (states)

  V    : airspeed [m/s]
 {alpha: angle of attack [rad]                                  }
 {beta : sideslip angle [rad]                                   }
  p    : roll rate [rad/s]
  q    : pitch rate [rad/s]
  r    : yaw rate [rad/s]
 {psi  : yaw angle [rad]                                        }
 {theta: pitch angle [rad]                                      }
 {phi  : roll angle [rad]                                       }
 {xe   : x-coordinate in Earth-fixed reference frame [m]        }
 {ye   : y-coordinate ''     ''          ''      ''  [m]        }
 {H    : altitude above sea-level [m]                           }

The state variables which are not actually needed by Dimless have been displayed between curly braces.

Outputvector: ydl

  ydl = [pb/2V qc/V rb/2V]' (dimensionless rotational velocities).

  pb/2V: dimensionless roll-rate  (b = wing span)
  qc/V : dimensionless pitch-rate (c = cbar = mean aerodynamic chord)
  rb/2V: dimensionless yaw-rate   (b = wing span)

Parameters to be defined in the Matlab workspace