History and Evolution of Parachute Design

The first known parachute design, sketched in 1495 by Leonardo da Vinci, was a pyramid-shaped canopy supported by wooden poles. This early design was not tested until the 19th century, when a significant flaw was noted -- the chute violently swayed and oscillated during descent. This was because the air that the parachute had passed through—called its wake—was forming alternating eddies behind the canopy, first on one side and then on the other. This made the canopy begin to oscillate, which caused air inside the canopy to "spill out" from alternating sides, making the swaying more extreme.

The early designs lacked a vent at the top or apex of the canopy. Adding a vent there produces a vertical stream of air in the middle of the wake that combats the formation of alternating eddies. Oscillations are dampened and chute descent becomes more stable.

Parachute Design Tip: During moments when a parachute is tipped at an angle during an oscillation, it falls faster (and also is at risk of collapsing completely). Reducing oscillations keeps the parachute oriented so that it creates the most drag.