m/e ee: by using c device known as a "shake table." As for the pressure gage, positive and negative calibrate steps were obtained, and the final cali- bration expressed as acceleration versus per cent cal, A typical calibration curve is shown in Fig, 2.16, Fig. 2.16 Typical Calivration curve for Accelerometer , Bending, Shear, and Torsion The calibration procedures described in this section apply only to instrumentation designed such that the output of @ single bridge, con- sisting of from4 to 16 strain gages, is used to determine the value of the response function. Calibration of the cending, shear, and torsion gages, as defined aimve, will be termed standard or conventional calibration and is basically the same for the three gage types. In essence, the calibration comsists of subiecting various portions of the aircraft to certain known lasads, such that the exact value of a particular functicn, for example, tending moment, can be calculated at a given page location. Gage outpatts are then related to the calculéted values of their related function over the desired ranze. , To calibrate for wing bending momert, it was necessary to support the aircraft at points along the fuselaze so ‘that no load was car- ried oy landince gear attacned to tne Wings. «a deat weirnt relieving load was tnen applied at various points along the «ing wri. tne zages balanced for zero output. Incremental distributed loads were tnen applied in gradually increasing amounts up to a maximum ailowaiie value and then removed arain in a similar step-wise manner until the zero stress condition was again attained. The gage output was recorded wach time the applied lead sas changed for both the loading and unloading phases, The gages were calibrated for both up~bendine and down-cending. Calioration steps were emcloyed as cefore and the final calictratior repressed as in-lb of ber.ding moment versus per cent cal. Calicrazion af the tending gages on the fuselage and horizontal statilizers was accomrlisned by the sane method used for wing vending calicration. 4*:rne momted landin. gear was allowed to taxe load while calicratins the fuselarr ani emrennaze. Framework and apparatus used to apriy tne c.licrating .oads ere snown oe aa Pr +ee i mae: @ Hs gr tage a in Fig. 2.17. omeme. sc to known accelerations while con~ nected to an oscillograph through 4 bridge balance unit in the manner employed for field measurements. Desired accelerations were obtained eae Accuracy of the instrument was found to be within the accuracy of the calibration. Accelerometers were calibrated by subjecting the instrument 2.3.7.2 . operation of the pressure measuring device was checked by measuring blast pressures produced in a shock tube.