Chapter 2


TS-100 describes the various ram-air construction methods such as half-cell chordwise, full-cell “I” beam chordwise, full-cell interlocking “T” chordwise, and spanwise configurations. When learning the various construction methods, the beginning rigger can become confused as to how the seams are folded together. Seeing the schematic diagrams of the various configurations can help in the repair sequence.

Round parachute construction is divided into two primary techniques: bias and block construction. Bias construction is most prevalent in the early parachutes and military designs. It is generally the stronger of the two techniques due to its ability to stretch more during opening. In bias construction, the fabric is cut and sewn so that the warp and filler threads are at 45 degrees to the centerline of the gore. A typical example is the 28' C-9 canopy.

Block construction is where the warp threads of the panels are parallel to the hem of the canopy. Block construction gained in popularity in the lightweight sport reserves of the 1970s and 1980s. They were easier to build and packed smaller. An example of this design is the Phantom/Aerostar canopies, manufactured by National Parachute Industries, Inc.


The rigger must have knowledge of how the parachute functions. Without this, the rigger may not be able to assemble the correct components so that they function as a complete assembly. While the manufacturer may specify what components are to be used with their particular design, with the vast numbers of products on the market today, there are an infinite number of combinations being used by the skydiving community. While seeming to be compatible with each other, many designs have subtle differences that affect their performance and operation.


The materials used in construction have changed over the last several years. This has resulted in better performance and durability. The use of incorrect materials can have a detrimental effect on the opening, flying, and landing characteristics of the parachute. The growth in popularity of the ram-air canopies in the 1970s required new fabrics for the designs to function. Very low permeability fabric was necessary for the canopy to remain inflated and maintain the aerodynamic airfoil shape. To reduce the drag created by the suspension lines, newer lightweight, and high-strength materials were used. First Dacron®, followed by Kevlar®, and now Spectra® and Vectran®. While reducing the line bulk and drag, these materials have introduced newer problems into the designs.

The ultra-low permeability fabrics inflate faster, and have almost zero stretch. As a result, the opening forces increase considerably. These effects have contributed to newer packing and deployment methods to reduce the loads on the parachutist and harness. These, in turn, affect the design of the container systems. Using this as an example, the rigger can see the chain of cause and effect in the design process. Complete coverage of materials is presented in chapter 3 of this handbook.


Damage patterns identified during the inspection of canopies can highlight problems caused from packing or incorrect use. By being able to identify these patterns, the rigger can provide the user with correct technique and, thereby, prevent possible injury or death. In addition, the rigger can provide valuable feedback to the manufacturer of potentially serious problems with new designs once they have been subjected to real world conditions. While manufacturers conduct extensive testing programs before releasing new products to the market, very often, subtle problems do not arise until the parachute has been in the field for an extended period of time.

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