Aerodynamics of Stream Thrust Probes

The ability to determine local stream thrust (a vector quantity) from a measured pitot pressure (a scalar quantity) requires either knowledge of the flow direction, or a probe shape that compensates for flow direction. This compensation ideally would make the measured pressure directly proportional to the component of momentum along the probe axis. A derivation of the flow angle sensitivity required to resolve this component of momentum is given. The flow angle sensitivities of several nose shapes are investigated and compared to the desired distribution. A parabola/cylinder is found to be superior to a hemisphere/cylinder, as it agrees with the desired distribution to within 0.5 percent to flow angles up to 15 deg.