Downloaded from https://www.everyspec.com ADS-65A-HDBK Reference(s): SAWE RP-7D, Mass Properties Management and Control for Military Aircraft 4.8.3.9 Stress Analysis Verify Stress on the Aircraft from the Sensor System Standard: A stress analysis should consider the structural loading effects of the sensor system and mounting bracket on the aircraft. Compliance: Perform stress analysis of the turret, mount, associated hardware, and aircraft structure to verify that positive margins of safety in all modes of flight. Flight loads should be in accordance with the aircraft specification and structural loads criteria. 4.8.3.10 Preliminary Dynamic Analysis Verify Dynamic Compatibility Standard:
The equipment as mounted to the aircraft should not have modal frequencies near the four frequencies with the highest amplitude peaks of the specification spectra. Compliance: A preliminary dynamic analysis should be performed to determine the fundamental dynamic properties of the sensor system/subsystem. These properties should include, but are limited to: 1) Resonant frequencies, damping, and mode shapes of the installed system. 2) The forced response of the installed system with the forcing frequencies of the host equal to the primary forcing frequencies of 1P, 1nP, 2nP, 3nP, and 4nP (where n = number of blades and P = rotor angular velocity).
3) The installed system dynamic effect on the weapon and the host system. Sensor systems mounted on fixed wing aircraft will be subjected to vibration levels and profiles of the host aircraft. And, compliance to this requirement should be checked when the equipment is first mounted on the aircraft by means of a rap test (modal testing) or an Aircraft Shake Test. Reference: ADS-27-SP 15