Two Main Types of Parachute and Their Parts
There are two basic types of parachutes -- (1) pure
drag chutes and (2) lift-producing
The traditional hemisphere-shaped chute (right) works
by producing a vertical drag force
that opposes the direction of travel. This chute type
produces drag when it falls by forcing
the air below it around its sides or through its vent.
Materials used in real canopies are also porous
to air flow -- air slows down as it passes through the
material, providing additional drag. In addition,
skin friction is created when air flowing along
the surfaces of the canopy and the suspension lines
slows down due to its rubbing contact with these materials.
A second type of parachute produces both lift
and drag, much like an airplane wing. Such canopies
are often cut in a rectangular shape, and create
lift when the air flowing over the canopy's top moves
faster than the air moving below it. The resulting airfoil
-- where the pressure of the faster moving air above
is less than that of the slower-moving air below --
creates lift on the canopy. A conventional hemispherical
chute will sometimes act like an airfoil, when the requisite
airflow gets established across its canopy.
Parachute Design Tip: A chute can
be identified by its flight path. In
still air, a chute acting in pure drag will travel straight
down. Those acting as an airfoil will fly diagonally
downward. The angled pathway is longer and so results
in longer descent times.