Method for static divergence analysis of sting-mounted wind tunnel models

Occurrence of static divergence will result in a catastrophic failure of wind tunnel models supported13; on sting or other types of support . The report presents an analysis method that can be used to design and/or13; verify the design of a model-balance-sting system for preventing occurrence of static divergence of the system. Detailed explanations are given to provide a clear understanding of the static divergence phenomenon. A brief discussion indicating the conditions for which divergence can become a concern and various design factors that the designer can consider to meet the stipulated criteria, is also included . In order to ensure adequate margin of safety against divergence in pitch plane the system must13; satisfy the following criteria : i) divergence parameter D shall not exceed a value of 0 .2, and, ii) elastic13; deflection of the balance-sting combination should be limited to 3 xB0;. Excellent agreement shown between calculated and test deflection data on a typical model indicates the high accuracy of the method of obtaining model deflection and angle of attack .