| 摘要 |
FIGURE 2 shows an airship (1) having a rigid plastics hull (2) generally of ovoid shape and filled with a lifting gas such as helium so that the airship of pressurized monocoque construction. The airship (1) has four expandable ballast air bags/containers (3, 4, 5, 6) and air can be introduced into and released from the bags/containers through apertures (not shown) in undercarriage (8). Four angularly spaced tail fins (7) are provided for aerodynamic trim control in forward motion (but not at low airspeeds). If air is pumped out of bags (3, 4, 5, 6), by pump means operated by control means in the undercarriage 8, a controlled ascent of airship (1) can be achieved, control being maintained by controlling the amount of air ejected from the bags. When descent is desired, ballast (air) is pumped into the bags (3, 4, 5, 6) from the ambient air, thus increasing the load carried, again under control, without gas loss, and enabling the airship (1) to achieve and maintain a desired height, without recourse to forward speed or aerodynamic forces. |
