Oe DD Ew "WE ee Shear gages were calibrated coincidentally with the bending Calibration consisted of summing applied loads outboard of the ans aid “ ayy - ee ee oe gages. Fig. 2.17 Calibration of B+36D Aircraft Empennage in Structures Test Facility of aircraft Laboratory gage location and plotting these loads as a fumction of the galvancometer deflection expressed as a percentage of cal, The only torsion gage was installed in the left outer wing panel of the 2-36D aircraft. For cali- bration, a dead weight relieving load was apriied so that bending and shear stresses, as well as torsional stresses, were reduced to zero at the gage location. As before, the gage was balanced out and czlibration steps taken, after which a vertical force couple was applied outboard of tne gage, such that the lezding edge was deflected upward and the trailing edge downward and vice versa for the negative torsion calibration. Because torsion was applied by a couple action, the total bending and shear induced was zero. The torsion applied was determined by the magnitude of the force coupie and the distance of the points of application from the elastic axis, The in-lb of torque applied for each load increment was calcul.ted, and gage output, expressed as a percentage of cal, was plotted versus torsional sesponse in in-lo.