Istoria aparatelor de zbor altele decât avioanele

1. INTRODUCTION

There are two kinds of floating lighter-than-air or LTA craft: the balloon and the airship. A balloon is an unpowered LTA craft that can lift. An airship is a powered LTA craft that can lift and then maneuver in any direction against the wind.

Balloons and airships lift because they are buoyant, meaning that the total weight of the airship or balloon is less than the weight of the air it displaces. The Greek philosopher Archimedes first established the basic principle of buoyancy.

All airships have solid gondolas, engine-powered propellers and solid tailfins and are classified as it follows:

- Rigid - usually long (greater than 360 ft/120 m) and cigar-shaped with an internal metal frame and gas-filled bags.

- Semi-rigid - pressurized gas balloon (envelope) attached to a lower metal keel.

- Non-rigid (blimp) - large gas-filled envelopes.

A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries passengers and a source of heat, in most cases an open flame caused by burning liquid propane. The heated air inside the envelope makes it buoyant since it has a lower density than the colder air outside the envelope. As with all aircraft, hot air balloons cannot fly beyond the atmosphere. The envelope does not have to be sealed at the bottom, since the air inside the envelope there is at about the same pressure as the surrounding air. In modern sport balloons the envelope is generally made from nylon fabric and the inlet of the balloon (closest to the burner flame) is made from a fire resistant material such as Nomex. Modern balloons have been made in all kinds of shapes, such as rocket ships and the shapes of various commercial products, though the traditional shape is used for most non-commercial, and many commercial, applications.

CONFUSING TERMINOLOGY

Airships, Dirigibles, Zeppelins, & Blimps: What’s the Difference?

What is an Airship?

An airship is any powered, steerable aircraft that it is inflated with a gas that is lighter than air.

What is a Dirigible?

“Airship” and “dirigible” are synonyms; a dirigible is any lighter-than-air craft that is powered and steerable, as opposed to free floating like a balloon.

The word “dirigible” is often associated with rigid airships but the term does not come from the word “rigid” but from the French verb diriger (“to steer”).

Dirigibles include rigid airships (like the Hindenburg), semi-rigid airships (like the Zeppelin NT), and blimps (like the Goodyear blimp).

What is a Zeppelin?

A zeppelin is a rigid airship manufactured by a particular company, the Luftschiffbau Zeppelin of Germany (the “Zeppelin Airship Construction Company”), founded by Count Ferdinand von Zeppelin.

What is a Blimp?

A blimp (technically a “pressure airship”) is a powered, steerable, lighter-than-air vehicle whose shape is maintained by the pressure of the gases within its envelope.

A blimp has no rigid internal structure: If a blimp deflates, it loses its shape.