| Popis: |
A high-order tiltrotor mathematical model is developed and validated against flight-test data for the XV-15 and simulations of a large civil tiltrotor (LCTR) concept. Rigid body and inflow states, as well as flexible wing and blade states are used in the analysis. Wing flexibility is important when modeling large aircraft where structural modes effect the frequency range of interest for flight control, generally 1–20 rad/s. Details of the formulation of the mathematical model are given, including derivation of structural, aerodynamic, and inertial loads. A novel "quasi-multibody" approach, based on numerical kinematics but without equations of constraints, allows the modeling of complex, flexible aircraft configurations in an easy to set up, and computationally very efficient manner. Assessments of the effects of wing flexibility are given. Flexibility effects are also evaluated by looking at the nature of the couplings between rigid body modes and wing structural modes. |
