A blimp rise as because it is filled with a gas that is lighter than the air around it. A blimp rise also depends on the pressure of the gas inside to keep it inflated to its normal shape.
Blimps can cruise at altitudes of anywhere from 1,000 to 7,000 ft (305 to 2135 m). The engines provide forward and reverse thrust while the rudder is used to steer. To descend, the pilots fill the ballonets with air. This increases the density of the blimp, making it negatively buoyant so that it descends.
A blimp is a small, balloon like airship, especially one used for observation or as a barrage balloon. A blimp has engines to move it through the sky and controls for steering. A control car holds the pilot and carries six passengers.
Though blimps played a useful surveillance role in World War II, airships today are mostly used for overhead photography at sports events, and as massive flying billboards.
Today, the Van Wagner group, an airship organisation, estimates that there are only 25 blimps currently operating around the world; there are even fewer zeppelins.
The only blimps that fly regularly today are three blimps owned by the Goodyear Rubber Company. There are currently two blimps (non-rigid airships) and one semi-rigid airship in Goodyear’s U.S. airship fleet:
• Spirit of America (N10A), a blimp/non-rigid airship (model GZ-20A), based in Carson, California
• Spirit of Innovation (N2A), a blimp/non-rigid airship (model GZ-20A), based in Pompano Beach, Florida
• Wingfoot One (N1A), a semi-rigid airship (model LZ N07-101), based in Suffield Township, Ohio
They are filled with helium, and are used for advertising. You can’t help noticing a blimp when it rises and cruises the sky.
Content for this question contributed by Max Swanger, resident of Santa Cruz, California, USA