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The aeroelastic behaviour of a wing with an over-the-wing pylon-mounted ultra-high bypass ratio engine and high-lift devices is studied with a reduced-order model. Wing, pylon and engine structures are reduced separately using the modal approach and described by their natural frequencies and modes. The characteristic aerodynamic loads are investigated with steady and unsteady flow simulations of a two-dimensional profile section. These results indicate possible heave instabilities at strongly negative angles of attack. Three-dimensional effects are taken into account using an adapted lifting line theory according to Prandtl. Due to high circulations resulting from the high-lift systems, the effective angles of attack are in the range of the potential instabilities. The substructures and aerodynamic loads are coupled in modal space. For the wing without three-dimensional effects, the bending instability occurs at the corresponding negative angles of attack. Even though there is potential for improvement, including the three-dimensional effects shifts the endagered area to possible operation points.

This paper focuses on the flight mechanical characteristics of an active high-lift supported transport type aircraft. The presented configuration combines a boundary-layer controlled flaps system with the benefits of propeller slipstream deflection. The underlying aerodynamic models and assumptions are provided. The extraordinary flight performances especially at low airspeed will be pointed out, as well as potential weaknesses. Special attention is paid to the unusually strong aerodynamic couplings in the lateral motion. Therefore, flight dynamics characteristics will be presented and their challenges discussed. The key influences are pointed out and an outlook will be given, how to exploit this knowledge for safe and satisfactory aircraft operation and handling.

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