If you take as a model the old airships as constructed at the beginning of this century, then you will see that these ships, which were about 250 meters long, could only carry a maximum of about 60 tonnes of freight. The reason for this is to be found in their high structural weight (aluminum - structure in the envelope, Helium - gas-bags etc). About three of these huge ships would be needed to carry a load of 160 tonnes.

The most compact alternative for lifting a load using helium is a balloon. Steering a balloon from one location to another, however, takes a great deal of trouble and energy.

1 Non-rigid or pressure Airship
       a Non-rigid airships (Blimps) are most common. They are large gas balloons.
      The shape is given by their internal pressure. Solid parts are the passenger gondola and the tail fins
      (e.g. Goodyear blimp)

       b Hot Air Airships (Thermal Airships), offer a compromise between the ease of use as hot air balloons
       and the maneuvrability of an airships.

2 Semi-rigid Airship
       They usually comprise a rigid lower keel construction and a pressurized envelope.
       The rigid keel can be attached directly to the envelope or hung underneath.

3 Rigid Airship
       Rigid airships have an internal frame (Zeppelins). The rigid aluminum structure forms the airship.
       Rigid airships are only efficient when longer than 120m because a good weight to volume ratio is (or was)
       only achievable for large airships.

The first generation of CargoLifters (the CL160) are planned to carry payloads of up to 160 tonnes at a speed of 80 to 100 km/h and a maximum height of 2000 meters non-stop over several thousand kilometers.

What is needed therefore is a structurally light and aerodynamic airship. All these characteristics are combined in a semi-rigid airship.
A modern semi-rigid airship consists of an aerodynamically shaped envelope - which, like a balloon,
is kept "rigid" (see above) by the pressure of the gas (not an Aluminum structure) - and a gondola for the pilot, passengers, engines and systems, which is mounted underneath.

The extremely large weight of the payload (160 tonnes), crane equipment, ballast tanks etc. must be transferred to the envelope. In the case of the CargoLifter CL 160 this is done by means of the so-called keel, a fixed structure mounted beneath the envelope, which also houses everything else needed, such as the flight deck, crew's quarters, all systems etc.  This keel makes the CargoLifter semi-rigid.

To satisfy requirements involving all factors necessary for trouble-free operation, CargoLifter will be filled with 550,000 m³ of non-flammable Helium. Its length will be 260 meters and its maximum diameter not less than 65 meters. This is somewhat longer and wider than the Hindenburg.

Experience has shown that an airship of this size can be steered most easily by using cross-shaped tail unit. Maneuvering engines will be used to help steer at low speeds.
 

Length: 260 m
Diameter: 65 m
Technology: Lighter-than-Air, semi-rigid keel airship
Volume: 550.000 m³, lifting gas: Helium (non-flammable)
Payload: up to 160 tons
Max. payload size: 50 metres x 8 metres x 8 metres
Speed: 80 to 125 kph
Operating altitude: up to 2000 metres
Range: up to 10.000 kilometres
Series manufacturing: starting in 2004 / 2005

   Airship Information Site (Germany)

   Airship Image Library (UK)

   Airship Resources (airships, blimps)

   Airship Heritage Trust (UK)

   Airships, an Introduction (US)

    Global Skyship & Airship Operations' Blimp Site

    Rigid® Airship Design: Home Page

   Zeppelin, Über das Unternehmen

   Zeppelin Museum Friedrichshafen