Airship Ground Handling
Certainly one of the most interesting parts of airship engineering is connected with the handling of ships when they are not in flight. The problem of anchoring, mooring, towing, moving them over the landing ground into the shed, or securing them in temporary shelter, is one calling for as much resource and ingenuity in development as the construction of the ships themselves.
An airship makes her landing by flying slowly up to a landing party collected on the ground. She drops her trail rope, which is taken by the landing party, led through a pulley block secured to the ground, and then used to haul the ship down until she can be taken in hand by the party. A number of guys, led from suitable points along the length of the ship, are then manned by detachments of the landing party, and the ship secured in this way can be moved about in any direction. This operation presents little difficulty so long as the ship is kept carefully head to wind. The direction of the length of the shed is, however, fixed, and it may well happen that the wind is blowing across the entrance to the shed. I'nder these circumstances it is necessary to turn the ship broadside to the wind in order to pet her into the shed.
The process of entering the shed offers very considerable difficulty. A sideways force on the ship is many times greater than that due to the same wind truly end on. In the neighborhood of the shed the wind is very seriously disturbed and forms large eddies. In many cases wind screens have been erected in order to break the force of a wind across the mouth of the shed, but it appears very probable that the unsteady flow produced by these screens renders the ship more difficult to handle than she would be if no screens at all were provided. In order to decrease the disturbance caused by these screens, certain of them have been constructed with large gaps left at intervals, and others have been covered with expanded metal instead of corrugated sheeting. Both these devices tend very greatly to reduce the eddies formed by the screens.
The difficulty in handling the ship appears to be very largely due to gusts and variations in the strength of the wind, and also to the vertical component which the wind may have derived from the motion over sheds or screens and which tends to drive the ship down on to the ground.
Opinion appeared to incline to a complete absence of wind screens and the provision of side rails and travelers to which the guys of the ship can be attached. The difficulty of taking ships into their sheds must not, however, be unduly magnified, for ships working at patrol stations have frequently been taken into their sheds in winds of 35 m.p.h. Winds such as this would, of course, cause considerable risk to a rigid ship of the largest type.
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