One of the key performance metrics for propulsion systemrnevaluation is efficiency. A common way to estimate efficiencyrnis to form the ratio of output power to input power. For anrnelectric propulsor, the electric input power is easily monitoredrnfrom driver motor current draw. Output power involves severalrnmechanical quantities, one of which is net thrust. Actually determiningrnthrust for a propulsor integrated with a ship can berna challenging indirect measurement. This case study detailsrnan approach to determine the thrust by effectively using thernpropulsion struts as flexure transducers. By instrumenting thernstruts with an array of fiber optic strain gauges, a measuredrnstrain state can be calibrated to a known loading condition.rnThe efficacy of the static load calibration procedure will bernmost appreciated in future open water sea trials of a surfacerneffect ship outfitted with an electric drive propulsion system.rnThis study considers the details of this calculation along withrndesign considerations for strain sensor numbers and locationsrnfor such an endeavor.
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