hélice

Hélice is a term originating from the Greek word helix, meaning spiral or screw. It most commonly refers to a screw propeller, a device used to propel a craft through a fluid, such as air or water. The design of an hélice typically involves one or more blades that rotate around a central axis. As the blades rotate, they create a difference in pressure, pushing the fluid backward and thereby generating forward thrust.

The principle behind the hélice is based on fluid dynamics. The shape of the blades is often airfoil-like, designed to generate lift. This lift, when directed backward due to the rotation, translates into the propulsive force. The pitch of the hélice, which is the theoretical distance it would travel in one revolution, is a critical factor in its efficiency and the speed it can achieve.

Hélices are fundamental components in a wide range of vehicles. Airplanes and helicopters utilize them for propulsion and lift, respectively. Ships and submarines employ them to move through water. Even smaller devices, like fans used for cooling or ventilation, operate on the same basic principle of a rotating hélice. The development of the hélice has been a key innovation in transportation and mechanics, evolving significantly over centuries to improve performance and efficiency.