Downloaded from https://www.everyspec.com MIL-STD-81OC B 4.6.3.2.6 Captive flight test. The following procedure shall be performed so that both the lateral and vertical.directiOnsare tested tO their respective test levels. Separate testing for each direction shall be required unless one test is able to excite both directions simultaneously to their respective test levels. Two test levelsare required, a functional level and an endur- ance leve1. For each axis, one-half of the functional test shall be conducted first then the endurance test followed by second half of functional test.
The equipment shall perform according to the equipment specificationoperating requirements during functional testing. 4.6.3.2.6.1 Part 1. Random vibration shall be applied to the store using an input spectrum shape of the store mounted forward accelerometer,but at an input level 6 dB down from the calculated response level of the forward accelerometer. The input random vibration level shall then be peaked or notched in those portions of the frequency range where significant resonance response peaks were identified in 4.6.3.2.5.
The peaking and notching of the input spectrum shall be such that the significant resonance response peaka of each store mounted accelerometer in the direction of applied vibration shall be equal to or greater than their respective test levels calculated in 4,6.3.2.3 and figure 514.2-4A. When using the test setup of 4.6.3.2.4a, different attachment locations for the shaker to the store may be tried to determine an optimum point so that both ends of the store are simultaneously tested to their respective test levels. perpendicular to the store mounted accelerometerswhich were used to 4.6.3.2.6.2 Part 2.
The response of the accelerometersin the direction ) establish the test spectrum shall be compared to their levels specified in 4.6.13.2.3. For each frequency where the response of a (the) perpen- dicular accelerometer(s) is above their specified levels the following procedure may be used. 4.6.3.2.6.3 Part 3. Calculate at each of these frequencies a ratio of specified to observed levels for each accelerometerwhich was in the direction of vibration and those perpendicular accelerometer(s) which have excessive levels. These ratios shal1 be averaged so that an average value is determined for each frequency.
The input vibration spectrum shal1 be adjusted so that at each of these frequencies their respective average value shall be equal to unity. The duration of the functional and endurance test is given in table 514.2-IV and the test levels for each test are determined in 4.6.3.2.3. 4,6.3.2.7 Free flight functional test. For stores that are deployed by separation from the aircraft (free flight) such as bombs and missiles, a free flight functional test shall be conducted in addition to the captive flight tests of 4.6.3.2.6. The equipment shall perform according to the equipment specification operating requirements as specified in General Requirements, 3.2 during the functional testing.
Use 4.6.3.2.6, table S14.2-IV, and figure 514.2-4A to determine the test procedures, levels and frequency spectra for the free flight test except as noted below. S14.2-13 METHOD 514.2