Design and Development of a New Cargo Parachute and Container Delivery System

The U S Army Soldiers Systems Center, Product Manager Force Sustainment Systems at Natick , MA was tasked with the development of a new low cost Container Delivery System (CDS). The program plan was to develop a new airdrop container, a High Velocity parachute and a Low Velocity parachute as alternatives to existing CDS components. Current CDS is used to support missions that provide water, food and supplies to areas unreachable by other means or to quickly provide these items on the spot for military operations. In actuality, very few airdrop items are returned for reuse and only in training does reuse occur. The High Velocity parachute and a Low Velocity parachute use the same basic design principles to keep the costs as low as possible. The container has been simplified in construction and is still able to perform its mission. These designs are based on using a high tear resistant, low cost, woven, polypropylene material. New materials and methods to produce a low cost parachute were investigated during this program. This led to examining the basic premise of parachute design and to challenge some of these basic concepts to see if the labor costs could be reduced through a simpler design and using standard, low cost, commercially available material. These concepts eliminate reinforcement of the canopy and use the inherent strength of low cost, canopy stock width material, along with a slower opening design to withstand the high parachute opening shock. The suspension lines are tied directly to the canopy material, reducing the number of suspension lines and eliminating the labor associated with sewing them on. This innovative parachute design is new in both geometry and method of construction. This is a modified cross parachute design that uses several strips of fabric that cross the other fabric at 90 degrees and are spaced so that crown vents are created to increase the geometric porosity and reduce opening shock. The number of suspension lines are reduced using this new design. The standard 26 ft Ringslot High ‘V’ chute has 26 lines compared to the new 12 line design. The G-12 cargo parachute has 64 compared to the new 20 line design. The fabric runs from one side of the parachute over the top to the other side without a break in the fabric so as not to create weak points at junctions. c. Stitching is kept to a minimum by only sewing the edges of the wide material at their edges where they intersect the other fabric that crosses at the crown and at the ends. Fabrication can be accomplished by non parachute makers such as tent or sail makers. A low cost slider is used on the high velocity, high altitude parachute to further reduce opening shock. As a result, the cost is reduced by approximately 60% of the present inventory items and at the same time decent rate is reduced by 4 % to 12 %. Testing to date has been successful with the High Velocity chute and the container having completed all formal testing and are accepted for their intended use of loads up to 2,200 pounds and altitudes up to 25,000 feet. The Low Velocity chute has shown that it can deliver 2,200 pounds with a rate of descent of 25 feet/second and is now being tested in its final configuration before entering formal testing.This paper describes the new container and the design of the two new parachutes and discusses airdrop test results.