Analysis of Data for Requirement Evaluation of Military Personnel Canopies

Abstract

In the analysis of requirements for personnel canopies there are many pitfalls that must be overcome so that a clear picture of the canopy performance can be painted. This includes understanding of user requirements, instrumentation choices, development of appropriate test scenarios, and the processing of data into a clear and presentable forma t. This paper will discuss lessons learned in these areas for the Advanced Tactical Parachute System (ATPS) and Special Operation Forces Tactical Advanced Parachute System (SOFTAPS). ATPS is a complete system replacement for the US Army T -10D main canopy, reserve canopy, and harness. The SOFTAPS program is a replacement for the US Army MC1 -1D which will utilize the harness and reserve canopy from the ATPS program. The ATPS program has a performance requirement to “p rovide the jumper the ability to maneuver to avoid other jumpers and travel horizontally.” This does not define clearly what the user wants for a capability of the system. The approach taken during testing was to document what the ATPS system did with regards to canopy control performance, and com pare it to the currently fielded T-10D system. The challenge was to decide what critical data was necessary for analysis and then how to process the data into an understandable format. To understand the effect of canopy control, a 4 -DOF solution of positio n and jumper heading was needed, in addition to the time and type of jumper control inputs. The instrumentation decisions to achieve this are discussed in the paper. Also, the reduction of the data into a usable format such as strip charts and rendered vid eo is described along with the positives and negative s of each approach. The analysis of data into a useful format is critical to the success of a test program. Without understanding the correlation of cause and effect, the performance and characteristics of a personnel canopy cannot be defined. The SOFTAPS program has a requirement to have a “landing descent rate less than the MC1 -1C.” In order to evaluate the system performance of the SOFTAPS the orientation of the jumper, with respect to the wind directi on, must be collected as well as the vertical descent rate. This presents a challenge because the heading of the jumper’s body frame must be captured along with the wind direction throughout the drop. An area not typically addressed in the requirements fo r a system is the application of a measure to the data. For characterizing opening performance, YPG utilizes a running average of a set of test points. This average generates a smooth trace of the altitude loss versus vertical velocity, which is useful in understanding at what altitude loss events occurred and is key to the opening performance of the canopy and the determination of overall safety of the system. The requirements and system performance of the ATPS and SOFTAPS are discussed in detail in this paper. The paper also presents lessons learned for the ATPS and SOFTAPS programs, which includes a detailed discussion regarding altitude loss verses descent rate, opening shock, canopy control, and other personnel canopy performance measures.