Continuous Beta Sweep Test & Analysis Technique (CBSTAT) for Predicting Wing Drop Based on Static Wind Tunnel Testing

Abstract

During the development phase of the F-35 Joint Strike Fighter program, an unprecedented level of effort was dedicated to ensuring that the configuration was free from wing drop problems like those that have plagued many modern combat aircraft. Particular emphasis was placed on creating a reliable and efficient method for predicting wing drop using static wind tunnel testing. The culmination of this effort was the Continuous Beta Sweep Test & Analysis Technique (CBSTAT) which was developed and refined during numerous wind tunnel evaluations conducted over a two year period. The merit of the method was initially demonstrated by successfully predicting transonic Free to Roll results for multiple JSF configurations. The success of this correlation led the JSF Program Office (JPO) to approve funding for the evaluation of CBSTAT on other aircraft which have exhibited wing drop in flight. Wind tunnel testing on both the pre-production F/A-18E/F and the Harrier II verified that CBSTAT was successful in identifying regions of the flight envelope where wing drop events have been observed. A full description of the CBSTAT test technique is provided along with lessons learned and recommendations for future application.