Water Tunnel Tests of the MK13-1, MK13-2 and MK13-2A Torpedoes with Shroud Ring Tails

Abstract

The High Speed Water Tunnel is operated by the California Institute of Technology under Contract OEMsr-207 with the office of Scientific Research and Development and is sponsored by Division 6, Section 6.1 of the National Defense Research Committee. This report covers a series of preliminary water tunnel tests of a model of the Mk 13-1, 13-2, and 13-2A torpedoes with shroud ring tails added, and is a supplement to a previous report of this laboratory, entitled "Water Tunnel Tests of the Mk 1.3-1, Mk 13-2, and Mk 13-2A Torpedoes," file marked Section No. 6.1-sr-207-936, and dated November 9, 1943. In the course of the investigation covered by the latter report, it was found that the torpedoes of this series are highly unstable and that they are controllable only within an extremely narrow range of angles of attack. The tests reported herein were, therefore, suggested by this laboratory, and were authorized by Dr. W. V. Houston, Director, Special Studies Group, Columbia University, Division of War Research. The objects of these tests were to investigate the possibilities for improving the stability and controllability of these torpedoes by the use of shroud ring tails, and to discover the trends of variation of these characteristics with variations of the several design factors of the shroud rings. Nine different shroud rings were tested with the torpedo model. It was found that marked improvement of the stability and control angle of these torpedoes may be obtained, without appreciable detriment to other characteristics, by the addition of shroud ring tails. The trends of variation of the stability, control angle, rudder effect, and drag of the torpedo with variations of the shroud ring design were clearly brought out. The results of these tests are shown in Figures 11 to 19, 21 and 22, and are summarized on pages 9 and 10 of this report.