The Watertight Propeller Dynamometer of high capacity is sealed against pressure of up to 1 bar above atmospheric pressure and against relatively high vacuum (1 bar = 10 to the power 5 N/m2 = 0.1 MPa). Idle friction of the measuring shaft is small despite the use of sealing rings and is approximately 0.3 Nm for dynamometer and 0.4 Nm for dynamometer. The dynamometer can be used also for propulsion tests with relatively high torque and thrust values in ship models under water. That has slightly larger dimensions, but is of similar appearance. It is thus suitable for use in the measuring section of cavitation tunnels, as an inner drive dynamometer in ship models or in dummy bodies mounted in the measuring section of a cavitation tunnel.
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