ABSTRACT
My earlier text,* discusses various methods of measuring vector forces and torques. In general, it is not possible to measure such three-dimensional quantities directly; rather, we design uniaxial transducers to selectively measure the components of the vectors and then use computation to fi nd the vector magnitudes and directions. This chapter will explore those applications where there is suffi cient space available to use separate force transducers to measure each component of the vector. One such area of application of major importance to mechanical and aerospace engineers is the measurement of the forces and moments produced by aircraft or spacecraft engines, since knowledge of these quantities is vital to the prediction of vehicle performance. For air-breathing (jet) engines used in aircraft and missiles, the need originally was to measure only the thrust force along the longitudinal axis of the engine. As aircraft (such as the British Harrier) that use thrust vectoring as a control method were later developed, knowledge of all the forces and moments became important. For rocket engines, this need was there from the beginning of that technology.
