Loads analysis of a C-wing aircraft

Abstract

The study at hand provides a load analysis for the C-wing for various symmetric maneuver. The aircraft has its tail surfaces at the wings tip, using it in order to decrease the induced drag and work as control surface at the same time. The used software is NASTRAN with the Solver 144 for static aeroelasticity. Besides the loads analysis, the flight mechanic properties of the C-wing aircraft are investigated. The study of the flight mechanic properties includes a variation of the torsional stiffness and the position of the horizontal tail plane. In order to encounter elevator reversal, the torsional stiffness had to be multiplied by a factor of six. It is found that the torsional moments of the C-wing show a significant difference to standard wing configurations. The torsional moment is maximum at the wing tip, and is dominated by the forces from the tail. In case the state is statically unstable the trim-force on the HTP acts in the same direction as the lift and increases the shear loads and bending moments. Maneuver which require large HTP forces are indentified to be the critical load cases for the C-wing. These load cases are pull-up, push-down, checked and unchecked maneuver. For future design studies it is recommended to put additional focus on the position of the neutral point and to include elevator reversal as a criteria.