Parks College Parachute Research Group
History of the PRG
Introduction
For most skydivers, technical knowledge about how ram-air parachutes work simply
means going to the drop zone with enough knowledge to stay safe. But for a
team of skydivers in the St. Louis area, that knowledge alone is not enough.
Jean Potvin, a physics instructor at St. Louis University-Parks College,
and Gary Peek, a computer and electronics consultant, formed the Parks College
Parachute Research Group (or PRG) to answer questions about parachute
inflation and flight.
The Group's Beginnings
Jean Potvin first got interested in parachuting as a sport rather than
a research project. Being a physicist, he naturally got interested in
the theoretical aspects of the physics and aerodynamics of ram-air parachutes
and found that the inflation computer models used by researchers lacked the
accuracy needed by the designers of our modern gear. (No wonder, since such
models had been initially created for the description of the inflation of
round parachutes!) In 1994 Potvin began devising a new model more specific to
sport ram-air parachutes and, in order to validate this model, began jumping
with a helmet-mounted aerobatic aircraft G-meter and belly video camera to
record maximum opening force and canopy inflation times.
During this same period, Gary Peek was doing some research in another area of
skydiving. In 1990 he became interested in improving formation skydives by
learning more about fall rate, and began working on a device that could
periodically record the altitude during a jump and calculate freefall speed.
Devices like these are called "barographs", and some older style mechanical
barographs have been used in aviation altitude record attempts for many years.
But by using some of the same technology that has eventually made its way into
modern AAD's, Peek has developed a barograph that is small and lightweight,
and can be worn on the wrist like an altimeter.
Joining Forces
These two skydivers knew little about each other's work because they normally
jumped at two different drop zones in the St. Louis area, and were both quite
busy with their individual work. It was not until they participated together
in an exhibition jump at Parks College, (which was arranged by a former student
of Potvin's that often jumped with Peek), that their conversation turned to
their respective research projects. It was then that they finally realized
that they had a lot in common, and would benefit greatly by working together.
Almost immediately, their work as a team began. Potvin's mathematical knowledge
quickly provided a method for improving Peek's barograph, which continues to be
used by the Group to determine airspeeds during parachute deployment. Potvin
also told Peek of his interest in using an electronic device that would allow
him to record signals from force and pressure sensors mounted on risers as
part of his parachute opening force research.
Peek realized that a simple data recording device could be made with the same
technology that he had incorporated into his most recent barograph design,
so at his suggestion, Potvin purchased the components necessary to build the
device. Peek quickly put it all together, and after a small programming
modification, they were collecting jump data with the Group's first data
acquisition system made specifically for research jumpers.
Since that time, the Group has made hundreds of instrumented test jumps with
parachutes used by skydivers as well as by the U.S. government jumpers.
Peek has since designed and built a much more sophisticated system that can
collect and store data at a faster rate and from more sensors.
Projects
The Group has been working on various software development, wind tunnel
testing, and flight testing projects, and has developed the world's only
public database of sport parachute opening characteristics. Information
from this database has been a major part of presentations the Group has
given at several Parachute Industry Association International Symposiums.
The Future
As the number of applications for ram-air parachutes increases due to the
constantly evolving sport market, and because of increased interest by
civilian and military government agencies, there will be an expanding demand
for more accurate knowledge about the inner workings of parachutes. The
Parks College Parachute Research Group plans to continue to develope new
methods of collecting and analyzing data that can help provide some of the
knowledge required by these new and novel applications.
