The turbine test rig requires two separate units for recording torque and thrust. A set-up using flexures and strain gages is best from the standpoint of accuracy, ease of operation, first cost and neatness of design. At the outlet end of the rig it wasfound that a tube 1/2" in diameter and with .010" wall thickness gives strain gage readings in a usable range for both the torque and the thrust loads that will be used.At the inlet end of the turbine test rig a more complex unit is required. A tube 2" in diameter with a wall thickness of .030" gives a good range of strain gage readings for the torque. What is required for thrust is a diaphragm arrangement schematically indicated by Fig. 2. The core is 2" in diameter and the outside diameter is 4". Calculations show the required thickness of the diaphragm to be .124".The two components at the inlet end can be welded into a single piece. The physical set-up of the turbine test rig with the two torque-thrust flexure units is shown on drawing P-15 .These calculations are not intended as a basis for determining constants that convert indicator readings to pounds of thrust or foot-pounds of torque. These constants will be obtained by calibration tests through the application of known forces and moments.
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