Design of a special twin sting support system for force measurements on a launch vehicle model

Conventionally, launch vehicle models are mounted on sting support systems for overall force / moment measurements in the 1.2m Trisonic wind tunnel of National Trisonic Aerodynamic Facilities (N.T.A.F.), National Aerospace Laboratories(CSIR-NAL), Bengaluru. However, this concept of mounting has always resulted in distorted base of the core and modification/removal of the core nozzle(s). A design concept was required to test the configuration without distorting the vehicle core and to simulate the core nozzles fully, as CFD predictions showed a substantial change in loads in the presence of core and nozzles. The design incorporates a special twin sting support system with an unconventional model assembly,which permits full simulation of the core nozzle. The balance is mounted in the core vehicle and attached to the twin stings through an adaptor .The design features of the special support system and the novel approach in the integration of model to support system is described in this paper