Efficient Methods for Complex Aircraft Configuration Aerodynamic Characterization using Response Surface Methodologies

Abstract

†‡ § A Response Surface Methodology (RSM) approach to wind tunnel testing of aircraft with complex configurations is being investigated at the Langley Full-Scale Tunnel (LFST) as part of a series of tests using Design of Experiments (DOE). An exploratory study was conducted using RSM and a 5% scale blended wing body model in an effort to efficiently characterize aerodynamic behavior as a function of attitude and multiple control surface inputs. This paper provides a direct comparison of the DOE/RSM and one factor at a time (OFAT) methods for a low-speed wind tunnel test of a Blended-Wing-Body (BWB) aircraft configuration with eleven actuated surfaces. A modified fractional factorial design, augmented with center points and axial points, produced regression models for the characteristic aerodynamic forces and moments over a representative design space as a function of model attitude and control surface inputs. Model adequacy and uncertainty levels were described using robust statistical methods inherent to RSM practice. Experimental goals included the capture of fundamental stability and control data for simulation models and comparisons to baseline data from recent OFAT tests. Optimization is demonstrated for actuator allocation for a desired response. A discussion of highlights and problems associated with the test is included.