Aeroelastics Flight Dynamics Coupling Effects of the Semi-Aeroelastic Hinge Device

Abstract

A recent consideration in aircraft design is the use of folding wing-tips with the aim of enabling higher aspect ratio aircraft with less induced drag, but also meeting airport gate limitations. This study investigates the impact of floating folding wing-tips on the aircraft flight dynamics. It is found that a floating wing-tips aircraft has similar handling qualities with respect to an aircraft with no wing extension.

Investigation of Sloshing Effects on Flexible Aircraft Stability and Response

“…The present modeling of coupled aeroelasticity and flight dynamics is based on the formulation in Refs. [11,12], in which the rigid body degrees of freedom are associated with a set of pratical mean axes (PMAs) and the linearized structural dynamics is described as a combination of unconstrained aircraft mode shapes in the PMAs coordinate system that simplifies the inertial coupling description. The PMAs are featured by having the origin coinciding with the instantaneous center of mass of the aircraft, and the orientation of the principal axes remains constant in the deformed configuration.…”

“…The linearized relation between Δ in Eq. (12) and Δ is expressed as with which allows to highlight the link between the variables expressed in the PMAs and those defined in the inertial reference system (being * 1 a square matrix with dimension ( 9 + N e )).…”

“…Although is generally provided by assuming modes defined in the inertial frame of reference, it can be easily transformed as done in Refs. [11,12] to be applied when body-frame coordinates are used instead. The GAF matrix is then approximated via following rational-polynomial interpolation in the reduced frequency domain Then, analytical expansion allows to express unsteady aerodynamic forces in time domain as it follows:…”

“…The mass e , damping e , and stiffness e matrices of the integrated system are the same as in Refs. [11,12]. Moreover, the description of the aircraft motion in the PMA non-inertial reference requires accounting for the projection of the weight force on the aircraft body reference.…”

Flight Dynamics of Transport Aircraft Equipped with Flared-Hinge Folding Wingtips

“…For the larger wingtips, there is an increase in the roll damping coefficient due to both downward and upward deflections by an amplitude of 4 and 2%, respectively, when compared with the baseline aircraft at similar flight conditions. Similarly, Castrichini et al [13] studied the impact of the semiaeroelastic hinge (SAH) on the flight dynamics of a narrow-body transport aircraft. They concluded that an aircraft equipped with floating wingtips has similar handling qualities with respect to an aircraft with no wing extension.…”