Parachuting, also known as skydiving, is the sport of jumping from enough height to deploy a fabric parachute and land safely.
A typical jump involves individuals jumping out of an aircraft (usually an airplane, but sometimes a helicopter or even the gondola of a balloon), at approximately 4,000 meters (around 13,000 feet) altitude, and free-falling for a period of time before activating a parachute to slow the landing down to safe speeds.
By manipulating the shape of the body—as a pilot manipulates the shape of his aircraft's wings—a skydiver can generate turns, forward motion, backwards motion, and even lift. Experienced skydivers say that in freefall one can do anything a bird can do, except go back up.
When leaving an aircraft, for a few seconds a skydiver continues to travel forwards as well as down, due to the momentum created by the plane's speed (known as throw-forward). The perception of a change from horizontal to vertical flight is known as the "relative wind", or informally as "being on the hill". In freefall, skydivers generally do not experience a "falling" sensation because the resistance of the air to their body at speeds above about 80 km/h provides some feeling of weight and direction. At normal exit speeds for aircraft 140 km/h there is little feeling of falling just after exit, but jumping from a balloon or helicopter can create this sensation. Skydivers reach terminal velocity (around 190 km/h for belly to Earth orientations, 240-320 km/h for head down orientations) and are no longer accelerating towards the ground. At this point the sensation is as of a hard wind.
Pret pour le Chut Libre!
No comments:
Post a Comment