When most people think of aircraft, they envision jet- or propeller-powered airplanes. Jet airplanes use one or more jet engines to burn a mixture or gas. This process, known as combustion, creates hot exhaust gases that propel the airplane forward. Propeller-powered airplanes have an engine that turns a propeller blade, which propels the aircraft forward. In addition to jet- and propeller-powered airplanes, however, there are lighter-than-air aircraft.
#1) Use Gas That’s Less Dense Than Air
Lighter-than-air aircraft leverage gas that’s less dense than air to achieve lift. In the past, many of them used hydrogen. Due to the highly flammable characteristics of helium, though, most lighter-than-air aircraft now use helium. Helium is about 13% as dense as air. With its low density, it naturally rises. Lighter-than-air aircraft feature balloons of helium or a gas of similar density to achieve, as well as maintain, lift.
#2) Originated in Ancient China
The origins of lighter-than-air aircraft can be traced back to Ancient China. In the 3rd century BC, China created small lanterns that would float in the sky. Known as sky lanterns, they were typically used in celebrations. Sky lanterns weren’t filled with helium. Instead, they featured a small flame within a canopy. Nonetheless, sky lanterns generated buoyancy in a similar way as modern-day lighter-than-air aircraft.
#3) Multiple Types of Airships
There are multiple types of lighter-than-air airships, including rigid, semi-rigid and non-rigid. The Zeppelin is an example of a rigid airship. Airships with only partial frameworks are classified as semi-rigid. Finally, blimps, such as modern-day blimps with helium-filled balloons, are considered non-rigid airships. All three types of airships are lighter-than-air aircraft.
#4) Applications
Most lighter-than-air aircraft aren’t used to transport passengers or cargo long distances. Instead, they are used in other applications. Some of them are used for environmental and weather tracking. Other lighter-than-air aircraft are used for advertising. You’ll often see blimps with brand logos and messages hovering over packed stadiums.
#5) Opposite of Heavier-Than-Air Aircraft
Lighter-than-air aircraft are the opposite of heavier-than-air aircraft. As the name suggests, heavier-than-air aircraft are denser than air. Airplanes, regardless of size, are typically classified as heavier-than-air aircraft. They are denser than air, meaning they must leverage some sort of propulsion mechanism to overcome their dense body and achieve lift.
Lighter-than-air aircraft lack the speed of their heavier-than-air counterparts. They are also more prone to weather-related disruptions. Nonetheless, their ability to fly using gas allows them to essentially float in the air.
