Sahreiber, Bentkowsky and Kerr 



DISSUB ROLLED 22.5 DEG 



40 



PITCH & ROLL ANGLES REQUIRED 

 TO PARALLEL HATCH PLANE 



40 



O 



UJ 



10 - 



C YAW ANGLE REQUIRED TO 

 MAINTAIN ZERO SWAY FORCE 



O 

 il.2 



YAW ANGLES (DEG) 



5 10 15 20 25 



DISTANCE TO HATCH (FT). 



30 



CURRENT COMPONENTS IN DSRV 

 FO« ANGLES AS IN (A) v 



4000 



YAW MOMENT UNDER CONDITIONS 

 • OF (C) 



/DIRECTION OF MOMENT IS\ 

 ATO INCREASE ANGLE / 



30 60 



YAW ANGLE (DEG) 



5 10 15 20 25 



DISTANCE TO HATCH (FT) 



Fig, 34. Counteracting Interaction Forces by Heading Changes 



pitch plane control. 



A six channel recording of the simulation test run under 

 these conditions is shown in Fig, 35, The variables plotted are the 

 displacexnents x, y and z of the camera of the DSRV from the 

 center of the hatch in the coordinate frame of the DSRV as shown 

 in Fig, 32, Also plotted are the roll, pitch and heading angles of 

 the DSRV, zero heading being into the free stream. For a one 

 minute interval during the run the roll, pitch and yaw angle traces 

 are replaced with RPM traces from the forward vertical, forward 

 horizontal and main propeller , respectively. 



The run begins with the DSRV aligned with the free stream, 

 in a level attitude, and at a camera elevation of 20 feet (correspond- 

 ing to 15 foot distance between the DSRV seal and the DISSUB hatch). 

 This initial condition results in a more severe transient than would 

 occur on a mission, so that the advantages of the relative proximity 

 in distance is overcome by the necessity to restrore dynamiic equili- 

 brium. At the start the pilot turned to port about 20 degrees to try 

 to miaintain equilibrium. Simultaneously, the roll and pitch angles 

 are adjusted to try to maintain the DSRV sealing surface parallel to 

 the hatch plane. After about two nainutes, the pilot descends about 



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