Chapter 2


The containers of today do more than simply enclose the canopy and deployment device. Sport containers in particular need to be designed so that they contribute to the deployment needs of the specific parachute. Piggyback designs have separate requirements for the main and reserve containers.

The reserve container is generally small, tight, and mostly wedge-shaped. Virtually all popular sport systems are designed around the use of a ram-air canopy. The deployment method of choice is a Type 5 deployment bag. In the early days of the ram-air reserve, there were certain container design requirements specified by the manufacturer. These were:

1. A hesitator loop configuration secures the bridle and holds the bag in until the reserve pilot chute is deployed and under drag. [Figure 2-9]

2. Nonrestrictive corners to allow the bag to be lifted off by the bridle in the event of a horseshoe-type malfunction. [Figure 2-10]

These requirements were adhered to for many years. Today, containers achieve the required holding and deployment needs through design tailoring. The bottom corners of the reserve container are designed so that the bag is held in place while the pilot chute and bridle deploy and then releases the bag to the airstream. At the same time, the bag can still deploy quickly in the event of a horseshoe-type malfunction.

The main container is less restrictive than the reserve in holding the main canopy in place during deployment. This is important so that there is no tendency for the bag to twist or be unstable on deployment. With many of the main canopies used today, if the bag is unstable, it results in the main canopy opening unevenly and causing spins and possible malfunctions. Along with the main bag, the main risers must be able to deploy evenly for the same reasons.

In the early days of skydiving, the primary body position was a stable, face-to-earth position. This resulted in the main container being behind the parachutist out of the airflow. One of the primary problems faced during those days was the high incidence of pilot chute hesitations. This was the result of the container designs and the relatively poor performance of the available pilot chutes. The advent of the hand deploy pilot chutes reduced the incidence of hesitations.

In the face-to-earth position, the primary purpose of the container is to hold the canopy and pilot chute closed and then allow it to open during deployment. Today, body positions experienced during free fall range from headdown to feet-to-earth and everything in between. Where speeds formerly experienced ranged from 110 mph to maybe 140 mph, today speeds in a head-down position can exceed 200 mph. This has changed the container dynamics to ensure a more secure system and increased protection from the wind blast. These changes have resulted in more secure and streamlined configurations to accommodate these new requirements. Figure 2-11 shows a modern container design shaped to meet the high-speed airflows of today.

An additional area that needs to be addressed when designing piggyback systems is the main riser covers. In the early days of sport piggyback designs, the main risers were held in position by webbing keepers. As the sport progressed, the use of fully enclosed main riser covers became the norm. In their attempt to protect the main risers during high-speed free fall, some designs tend to restrict the deployment of the reserve container in the event of a “total” main pack malfunction. When this happens and the main container remains closed, the main riser covers do not open. Because of this, there is additional restriction over the upper corners of the reserve container. This contributes to higher reserve bag release forces when deployed. In severe cases, this can result in a reserve pilot chute in tow with potential serious consequences. The balance between sufficient main riser protection and the need for full reserve deployment freedom can be an important design feature.

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