Water Tunnel Tests of the MK 25 Torpedo with Gas Exhaust Through a Horizontal Pipe

Abstract

This report covers tests made on the MK 25 torpedo to determine the effect of gas discharged through a horizontal exhaust pipe. This report is supplemental to the report, Section No. 6.1-sr207-1275, which described teats with the gas discharged through a vertical fin. It was requested by Dr. E. H. Colpitts, Chief of Section 6.1 NDRC, in a letter dated May 4, 1944. The objective of both this and the former report is to examine the effects of discharging the turbine exhaust gases through the fin structure instead of through the propeller shafts. Since the feasibility of this new method of exhaust discharge is greatly dependent on the effect of the gas flow on the afterbody fin structure and propeller zone, both studies have been restricted to the observation and analysis of this flow. Determination of the effects of the discharge passages and gas stream on the hydrodynamic stability, rudder control, and propeller efficiency have been deferred. Pending the development of an exhaust passage having discharge characteristics that are not visibly unsatisfactory. Several different lengths of exhaust pipe were tested; also, runs were made for various values of velocity and submergence and different amounts of gas discharged. Photographs were taken to show the exhaust cavities created under the different conditions.