Tennis

1034 mots 5 pages
1. History of aviation
In 1486 Leonardo da Vinci began studying birds. Over the next few years he speculated on mechanisms that could help man fly like a bird. He made hundreds of drawings of propellers, helicopters and parachutes. In 1487 da Vinci designed his first flying machine. At first his designs were based on the way bird's flew. Later he realised this was impractical and produced drawings of machines with fixed wings. He also experimented with what later became known as gliders.
The hot air balloon is the oldest successful human-carrying flight technology. On November 21, 1783, in Paris, France, the first manned flight was made by Jean-François Pilâtre de Rozier and François Laurent d'Arlandes in a hot air balloon created by the Montgolfier brothers.
A hot air balloon consists of a bag called the envelope that is capable of containing heated air. Suspended beneath is the gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule) which carries the passengers and (usually) a source of heat. The heated air inside the envelope makes it buoyant since it has a lower density than the relatively cold air outside the envelope. Unlike gas balloons, the envelope does not have to be sealed at the bottom since the air near the bottom of the envelope is at the same pressure as the surrounding air. In today's sport balloons the envelope is generally made from nylon fabric and the mouth of the balloon (closest to the burner flame) is made from fire resistant material such as Nomex.
Recently, balloon envelopes have been made in all kinds of shapes, such as hot dogs, rocket ships, and the shapes of commercial products. Hot air balloons that can be propelled through the air rather than just being pushed along by the wind are known as airships or, more specifically, thermal airships.
[edit] Early pioneers

Crossing of the English Channel by Blanchard in 1785.

A model of the Giffard Airship at the London Science Museum.

The navigable

en relation

  • Badminton
    1546 mots | 7 pages
  • Tennis
    474 mots | 2 pages
  • Tpp tennis de table
    1302 mots | 6 pages
  • Badminton
    291 mots | 2 pages
  • Badminton
    805 mots | 4 pages
  • Tennis de table situation
    1038 mots | 5 pages
  • Badminton
    1090 mots | 5 pages
  • Tennis
    4041 mots | 17 pages
  • badminton
    2938 mots | 12 pages
  • Badminton
    418 mots | 2 pages
  • Le Badminton
    1728 mots | 7 pages
  • Progrès mini tennis
    790 mots | 4 pages
  • Le mini tennis
    2454 mots | 10 pages
  • Badminton
    309 mots | 2 pages
  • le mental au tennis
    9488 mots | 38 pages