A propeller thrust and torque dynamometer for wind tunnel models

Abstract

The design, construction and calibration of a propeller thrust and torque dynamometer is described. The dynamometer was constructed primarily for the testing of model ship propellers when working upstream of a rudder. An outline of the specialised design requirements is given. The basic design concepts are described together with the reasons for the choice of flexures and their dimensions, strain gauges, circuits, bridge voltages and instrumentation. A brief description of the calibration process is given and the calibration results are described and discussed. It was found that there were no interactions between the components, a satisfactory overall measuring accuracy was achieved and the dynamometer had performed well in service. It is concluded that the overall design approach, concept and design details were satisfactory and suitable for this particular application.