Pump Performance of the Mark 40 Pumpjet

From the results of tests conducted in the Hydraulic Machinery Laboratory at the California Institute of Technology, the pump performance was analyzed and found to be satisfactory for the pumpjet installation in the Mark 40 Torpedo. The pump will operate at or very near the point of best efficiency, which is 84.5 ± 1.0 per cent at a projectile speed of 80 knots. The propulsion unit was tested from zero flow rate point through zero head point into the reverse turbine range. The performance was found to be very similar to that of a conventional centrifugal pump fitted with a diffuser vane case or a volute case.