The major components of a Non-Rigid Airship
Click on the picture to have a better view
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Aft
ballonet
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Envelope
The envelope is the large bag that holds the
helium gas. The envelope is generally cigar-shaped, for aerodynamic purposes,
and made of a durable, airtight, lightweight fabric (polyester composites)
that is much like the fabric of a space suit. The envelopes hold helium, and
the pressure inside them is low, approximately 0.07 lb/in2 (4.8 N/m2)
The nose cone battens are supports that radiate from the tip of the blimp. They stiffen the front of the blimp so that it is not damaged when it is moored to the mooring mast. They also give the nose an aerodynamic shape, and prevent it from pushing in as the blimp travels forward. In addition to the battens, the mooring hooks are located in the nose of the blimp.
Ballonets are air-filled bags that are located inside the envelope. The blimp has two ballonets, one fore and one aft. The ballonets are similar to the ballast tanks of a submarine. Because air is heavier than helium, the ballonets are deflated or inflated with air to make the blimp ascend or descend, respectively. They are also used to control the trim, or levelness, of the blimp.
Catenary Curtain and Suspension Cable
The two catenary curtains are located inside the envelope along the length of the blimp. They are made of fabric and sewn into the envelope, and suspension cables attach them to the gondola. The curtains help to support and shape the envelope and attach the gondola.
The flight control surfaces are stiff, movable parts of the blimp that are mounted to the tail. They consist of the rudder and elevators. The rudder is used to steer the blimp to the starboard or port directions (yaw axis). The elevators are used to control the angle of ascent or descent (pitch axis) of the blimp. The flight control surfaces are operated by the pilot as he/she flies the blimp, and can be arranged in a "+" or "x" configuration.
Engines
The two engines on the blimp provide the
thrust necessary to move ahead. The engines are turbo-propeller airplane engines
that use gasoline fuel and are cooled by air. The engines can generate several
hundred horsepower, depending upon the particular blimp. They are located on
either side of the gondola. With the engines, blimps can cruise around 30 to 70
mph.
Air Scoops
The air scoops direct exhaust air from the propellers into the ballonets. This
is how the pilots can fill the ballonets with air while in flight. When the
engines are not running, electric fans move air into the ballonets
Air Valves
The pilots must be able to vent air from the ballonets as well as add it. Air
valves that are located on each ballonet accomplish this. There are four valves
-- two fore, two aft.
The pressure of the helium in the envelope is adjusted by changing the amount of air in the ballonets. Normally, blimp pilots do not have to add or remove helium from the envelope. However, there is a helium valve on the envelope that can be used to vent helium should the helium pressure exceed its maximum safe limit. The valve can be opened manually or automatically.
This is where the pilot and passengers sit and is made of high-tech composite materials. It consists of the cockpit, cabin area and landing gear. The pilot and passengers are seated inside the envelope in a spacious cabin that is enhanced with large windows. These windows surround the base of the envelope and offer excellent visibility. A typical view of the Gondola is given below.
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Forward view of the inside of a gondola showing pilot seats/controls (front) and passenger seats |
Blimp gondola with an attached camera (round object in front) |
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Propeller controls - monitor and regulate speed (throttle), blade angle (blade pitch) and direction of the engine (forward, reverse). |
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Fuel mixture/heat - monitor and regulate the fuel-to-air ratio of the engine and the temperature of the mix to prevent icing at higher altitudes. |
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Envelope pressure controls - monitor and regulate the helium pressure in the envelope and the air pressure in the ballonets by opening and closing the air scoops and valves. |
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Communications - maintain radio contact with ground-support team and air-traffic controllers. |
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Flight surface controls - control the rudder (left/right movement) and the elevators (up/down movement). |
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Navigation equipment - compasses, airspeed indicators, radio beacon equipment, etc. Some blimps have weather radar, and are instrument-rated for night-flying. |
Night Sign Lamps
Blimps now have LED (Light-emitting diodes) signs instead of lamps and employs new fiber optic technology. The intensity of each LED board can be adjusted, in effect changing their mix to create a pallet of 256 possible colors.