Drag Estimates for the Joined-Wing Sensor Craft

This research studied the drag effects of the joined-wing sensor craft technology demonstrator being developed at the Air Force Research Laboratory (AFRL). Although many performance parameters have been studied and evaluated for this vehicle, to date no detailed drag estimates have been conducted for the AFRL configuration. Previous performance parameters of the aircraft have been estimated based solely on a constant lift-to-drag ratio assumption. Using the Air Vehicles Technology Integration Environment created by Dr. Maxwell Blair, and supplemented by MATLAB code, this study explored three different drag prediction methods to determine accurate estimates of both parasite and induced drag. The Roskam/AVTIE Pan Air method was determined as the best approach to estimate drag by measuring parasite drag effects using XFOIL, a respected environment within the aviation industry to accurately predict all viscous drag effects, and determined induced drag from Pan Air, a creditable software package based on inviscid flow field solutions about three-dimensional objects. This method will be incorporated into a single design environment, in conjunction with AVTIE, to estimate drag and aid future AFRL joined-wing design studies incorporating wing twist, aeroelastic effects, and other geometric changes to the baseline configuration