Estimation of the aerodynamic coefficients of the navion aircraft at high angles of attack and sideslip

Xavier Silhouette, Robert Stengel

Research output: Contribution to conferencePaperpeer-review

2 Scopus citations


The aerodynamic coefficients of the Havion aircraft were determined from flight test data using the Estimation- Before-Modeling technique. Fifteen maneuvers were performed during two test flights where angles of attack and sideslip above 30 degrees were reached. The forces and moments were estimated by an extended Kalman filter followed by a modified Bryson-Frazier smoother- The smoothed data were divided into subspaces of the angle-of-attack/sideslip-angle domain. In each subspace, aerodynamic models were obtained by 1 east-squares stepwise multiple linear regression. The global model was validated by matching the predicted and smoothed time histories of forces and moments. Pitch rate was found to be a strong contributor to lift, producing a dynamic effect that could be mistaken for hysteresis. In the pre-stall regime, the yaw stiffness, the dihedral effect, and the aileron and rudder control derivatives, decreased as the angle of attack increased. Both dihedral effect and yaw stiffness diminished as sideslip increased. The aircraft stalled at An angle of attack higher than anticipated as a result of thrust effects. Beyond the stall# elevator effectiveness remained significant, and there was a considerable reduction in dihedral effect, yaw stiffness, and aileron control. Asymmetric effects on both longitudinal and lateral- directional coefficients were determined by processing data for positive and negative sideslip angles separately.

Original languageEnglish (US)
Number of pages12
StatePublished - 1987
Event14th Atmospheric Flight Mechanics Conference, 1987 - Monterey, United States
Duration: Aug 17 1987Aug 19 1987


Other14th Atmospheric Flight Mechanics Conference, 1987
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Mechanical Engineering


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