AIRCRAFT DIRECTIONAL STABILITY AND CONTROL: NEW IMPROVED APPROACH IN TAIL DESIGN

This work deals with a review and proposed improvements of vertical tail classical design methods dealing with aircraft directional stability and control. The research presented is based on many numerical and experimental results obtained by the authors (DAF research group, www.daf.unina.it) through both CFD calculations and wind-tunnel tests carried out on an aircraft modular configuration. A new improved methodology to predict the directional stability and control characteristics of an aircraft and a reliable sizing procedure for the vertical tail is proposed. The methodology obtained and all results are particularly relevant for the regional turboprop category, but they can also be applied to other transport aircraft configurations. A wind tunnel investigation involving more than 150 configurations has also been involved in order to validate the numerical approach for which about 200 configurations were involved. The analyses covered both the linear and the non-linear range of the aerodynamic coefficients.