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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.
HARNESS DESIGN
According to Poynter’s Parachute Manual, “the harness
is an arrangement of cotton, linen, nylon, or Dacron®
webbing, which is designed to conform to the shape of
the load (usually the body) to be carried in order to secure
it properly so that the opening forces and the weight of
the load are evenly distributed during opening and
descent.”
The earliest harness was nothing more than a swing seat
that the parachutist sat on and then held onto the risers
or suspension straps. It soon became apparent that if the
openings were anywhere uneven, it could be very precarious
for the parachutist. While the sling seat worked
for the ride down, it was necessary to add additional
straps to secure the parachutist. These straps included
the leg, back, and chest straps. The standard harness
configuration is equipped to secure a torso, head, arms
and legs with straps. Others have been added over time
Figure 2-11.VoodooTM container profile.
2-8
for additional purposes such as survival kits or cushions.
Figure 2-12 shows a basic military style harness. This
harness configuration has seven points of adjustment to
allow fitting of most military personnel.
Most of the early parachute systems had the harness
detachable from the containers. This allowed interchangeability
for various models. In the 1970s, skydiving
systems began to integrate the harness into a true harness/
container assembly. This was accomplished by
sandwiching the harness between the container and
backpad and sewing them together. Figure 2-13 shows
one of the earliest custom systems called the “Super
Swooper.” This harness was the precursor of today’s sport
harnesses.
As skydiving and the sport parachute industry has grown,
most of the equipment is now custom-built for each individual.
The standard piggyback harness configuration of
today is a fixed main lift web with adjustments only at
the chest and leg straps. [Figure 2-14] Elimination of the
extra hardware and webbing has resulted in a dramatic
reduction in weight of modern systems. Along with this
has been an increase in comfort and flexibility. One of
the most innovative designs adopted in recent years is the
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Parachute Rigger Handbook(18)
