Aerodynamic Model Identification of the Flying V using Wind Tunnel Data

Abstract

The Flying V is a tailless flying wing with a V-shaped planform, where the passenger cabin has been integrated inside the main lifting surface. The main goal of this project is the aerodynamic model identification of this novel aircraft configuration, using wind tunnel data from a 4.6\% scaled model. Models using Multivariate Orthogonal Functions and splines were postulated for the aerodynamic forces and moments, in order to construct a global input/output model to estimate the aerodynamic response of the Flying V. The aerodynamic model structure was unknown a priori, and was determined from the measured data using a modified stepwise regression technique, which achieved parsimonious models with tight confidence bounds. The models were validated against a partition of the data, showing good prediction capabilities and reasonably random, uncorrelated residuals, especially in the case of the spline models.

The resulting models are analytical functions in the state and control variables, which can be used to determine the aerodynamic forces and moments of the Flying V at any given flight condition inside the region of validity of the model. Using the estimated models, a trim routine was programmed to calculate the thrust and control settings required for trimmed flight at different airspeeds and flight path angles. Bounds for the center of gravity regarding controllability and stability were calculated using the estimated models, and a feasible center of gravity location for the Flying V was identified. In addition, a safe flight envelope for the flight test can be defined from the results of the trim routine.