426 Alex Goodman 
Fig. 37. DTMB submarine simulator facility 
Definitive maneuvers which provide measures of the capabilities of the submarine tem- 
pered by the existence of a human operator or automatic control in the control loop can also 
be performed using the facility. Maneuvers such as depth-keeping and course-keeping, under 
various environmental conditions, provide numerical measures such as rms depth or course 
error, percent time on target, degrees traveled by control surfaces, and maximum values of 
these variables. Various other maneuvers such as limit-dives and emergency-recovery maneu- 
vers also can be performed in'the laboratory and evaluated before the submarine is built. 
Instrumentation studies, which are in the nature of human engineering, can be carried out 
using the submarine simulator. The effect of various displays, indicators, lighting, and other 
devices on the performance of the submarine can be evaluated. 
Thus, it can be seen that the DTMB Motion Analysis and Simulator Facility is a power- 
ful and versatile design and research tool for the study and analysis of stability and control 
problems. 
FREE-RUNNING MODEL TECHNIQUE 
The free-running model technique has been used extensively in the past in studying the 
turning and maneuvering characteristics of surface ships [4]. With the emphasis that has been 
placed the performance of high-submerged-speed submarines, the necessity for turning data 
from submerged model tests has become more important. Karly submerged maneuvering tests, 
in the vertical and horizontal planes, conducted at.the David Taylor Model Basin employed a 
specially constructed 5-foot model provided by NACA. The model was powered electrically 
and controls were operated by compressed air through a flexible tubing which trailed astern 
of the model. Model trajectories were obtained, by photographing the movements of the model 
