Date of Award


Document Type


Degree Name

Master of Science in Aeronautical Engineering


Department of Aeronautics and Astronautics

First Advisor

Christopher Shearer, PhD


This research effort examines the static effects of a KC-135 flowfield on a flexible winged Sensorcraft model. The KC-135 flowfield data is generated by a vortex lattice code and integrated into Sensorcraft model for analysis. Building on previous research, a refueling situation was modeled to note the effects of the Sensorcraft at varying locations within the flowfield. The Sensorcraft model was analyzed for both rigid and flexible wings as a means of comparision. Flowfield locations of interest were determined and trimmed conditions were computed for each flowfield location. Utilizing the trimmed condition and flowfield locations, the nonlinear set of EOM's were linearized in order to complete an eigenvalue/eigenvector analysis. Unstable eigenvalues were found for the rigid and flexible cases at all flowfield locations, and the specific contributions to the states were noted and classified accordingly. Results indicate that when the Sensorcraft was moved to different locations, the number and magnitude of the unstable eigenvalues fluctuated. Areas of the flowfield with increases in unstable eigenvalues were determined to be where the Sensorcraft experienced asymmetric loading, primarily when offset from the centerline of the flowfield. The additional elastic states for the flexible winged cases showed a significant increase in unstable eigenvalues.

AFIT Designator