> Design and Construction > Containers > Bridles and Deployment Devices > Securing the Deployment Device

With all deployment methods, it is necessary to properly fold or stow the canopy and secure the deployment device with the lines. The early parachutes utilized hesitator loops to secure the lines. [Figure 2-26] This method is still used today in many military systems.

Figure 2-26. Hesitator loops.

In modern designs that utilize types 1 through 4 and 6, the preferred method of locking the deployment device is rubber bands. The specification for standard rubber bands is MIL-R-1832. Type 1 are natural rubber and are 1/2" x 2". These were designed for use with the thicker Type III nylon lines such as on the 28' C-9 canopy. Many of the newer lightweight, round canopies use smaller diameter and fewer lines. Consequently, the standard rubber bands do not work well. Some manufacturers supply smaller diameter rubber bands to be used with their canopies. It is extremely important to utilize the correct size rubber bands.

With the introduction of the free bag system in 1977, Para-Flite, Inc., used a BUNA-N “O” ring to secure the locking stows. [Figure 2-27] During testing of the free bag system, they found inconsistent holding and breaking strengths of rubber bands. They wanted the locking stows to release at a consistent force to prevent bag lock. The “O” rings provided this. A couple of years later, the “O” rings were upgraded to a thicker diameter model. In 1983,

Figure 2-27. Para-Flite “O” rings.

Para-Flite, Inc. replaced the “O” rings with the Safety Stow®. The Safety Stow® is a continuous loop of elastic shock cord that runs through a webbing channel and through two grommets to secure the first two locking stows. [Figure 2-28] In the event of any restriction on the locking stow, as the loop stretches, it allows first one side to release and then the opposite side. This design is a considerable improvement over separate rubber bands or “O” rings and is used on most free bags today.

Figure 2-28. Safety Stow

It is important to maintain the rubber bands or Safety Stow®. Rubber bands are susceptible to heat degradation and dry out. If they break prematurely during use, the parachute may malfunction. Natural rubber bands also react to natural brass grommets and may become gummy and sticky, causing the lines to stick to the diaper or bag. [Figure 2-29] The BUNA-N “O” rings should be replaced with the Safety Stow®. The Safety Stow® should be inspected for broken stitching or internal rubber strands. [Figure 2-30]

Figure 2-29. Old rubber bands.

Figure 2-30. Bad Safety Stow®.