Dynamic Ground Testing of Standard Type XXVI Nylon Parachute Extraction Lines and Data Collection for Airdrop Applications

摘要

Understanding the performance characteristics of extraction lines selected for specific airdrop applications is vital to ensuring the survivability of payloads during nominal operations. As new payload configurations are introduced to expand the airdrop operational envelope unintended consequences can result due to reaching hardware performance limitations or experienced shock loads. A dynamic ground test effort is underway to collect fundamental spring stiffness and damping data for various extraction line lengths (60-ft, 120-ft, 140-ft and 160-ft) and multi-loop configurations (1-, 3- and 6-loop). The performance of a Type XXVI nylon extraction line is simulated using a spring-damping force function and limited to no data is available to characterize the spring-damping inputs during dynamic parachute deployment sequences. Each extraction line is tested using a pulley system configuration that uses a release mechanism to control the release of a payload weight that ranges from 4,100-lbm to a maximum of 21,500-lbm for this initial effort. Each weight will be used to simulate the opening force of a standard ring slot (RS) parachute (15-ft RS, 22-ft RS, 28-ft RS and two 28-ft RS). The test configuration is setup with an instrumentation suite that will collect direct extraction line loads and component (3- and 4-point link) accelerometer data to help derive representative spring-damping inputs. The instrumentation suite's performance will be tested against verified measurement devices to ensure the data is being collected accurately in the dynamic environment. This incremental approach is intended to build confidence in the data collection process, test hardware limitations, identify potential failure modes and refine the testing technique. The dynamic portion of the test will collect damping related data and a high-speed camera will be positioned in the test setup to collect displacement data to characterize the spring-stiffness of the extraction line. The ground-work performed will help improve extraction line modeling efforts, contribute to the development of the Airdrop Technology Multi-Operational Simulation (ATMOS) predictive capability and validate the instrumentation to use for upcoming program testing efforts for the Heavy Equipment Large Low Velocity Airdrop System (HELLVADS).