content_image/577610.jpg
## Canopy Design 

Accomplished design skills are not necessary for the rigger to properly service parachutes. The skills involved to become a designer can take several years of training and practice. It is necessary, however, that the rigger understands some of the basic concepts to relate the performance characteristics to the design theory of the components involved. For the average rigger, these concepts are accepted as those proven and tested in the finished product. The following are specific areas that the rigger should understand to determine the identity, function, and assembly of parachute components and their interaction. 

Understanding the sequence and method of deployment is necessary when assembling components to assure proper function. Most ram air parachutes are trimmed nose down, and as such the canopy tries to fly over its nose during deployment. This flight angle causes the top skin nose of the canopy to roll over the bottom skin leading edge closing off the cell preventing inflation. To counter this, the trailing edge of the canopy is deflected downward to apply brakes during inflation; this holds the nose up and open allowing air intake. These are called “deployment brakes” and are implemented by providing a “brake eye” in the steering line of the canopy located so as to apply the proper amount of brakes. The steering line is pulled down through the steering guide ring on the risers and locked with the nose of the steering toggle during the packing process. Loss of one or both brakes during opening will most likely cause a malfunction. Loss of one causes the canopy to turn into that side as the cells remain collapsed and the inflated side over-flies the collapsed side. In flight corrective action is to grab both toggles and apply both brakes evenly and quickly. 

## Nomenclature 

All riggers should become familiar with Parachute Industry Association (PIA) Technical Standard 100 (TS-100), Standardized Nomenclature for Ram-Air Inflated Gliding Parachutes (See Appendix I). This document is the official language and terminology used for ram-air parachutes. It specifies the parts of the parachute, the various construction methods, and the seam configurations used. This is necessary for the rigger to understand the manuals and repair procedures provided by the manufacturers for their products. 

Figure 2-6 identifies the components of a typical round emergency parachute. The nomenclature of this design has remained constant for several decades with a few exceptions. While some riggers who skydive think that the square parachute has replaced it, the round parachute still has many uses, and in certain instances, fulfills some 

<img src='content_image/577610.jpg'>

mission requirements better than the square parachute. Poynter’s Parachute Manual, Volume 1, Chapter 8, provides an excellent discussion of the design parameters and characteristics of round parachutes for those needing more technical background. 

## Construction Concepts and Techniques 

TS-100 describes the various ram-air construction methods such as half-cell chord wise, full-cell “I” beam chord wise, full-cell interlocking “T” chord wise, and span wise 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. Additionally, there are two basic methods of construction for the main seam used on modern ram airs. One method is to roll the adjacent bottom skins with the attendant rib together and double needle 301 stitch to hold the joint. Line attachment tabs are then appliquéd over the rolled seam for subsequent line attachment. The other method is the foil method where the rib has the line attachment tab attached directly to it and is flat stitched to the bottom skins allowing the bottom edge of the rib to be exposed. 

