Nothing is more interesting to note in modern airships than the simplification of the method of car suspension. In the early airships the car was hung from the envelope by a large number of cables, which either connected with a network that fitted over the envelope, or else, in a semi-rigid dirigible, to the platform or keel at the base of the balloon.
Now of course all these cables offered a great resistance to the air and were an enemy to speed. Just as the question of speed affected the shape of the envelope, until to-day we have the streamline balloon, tapering to the rear, and just as it made the question of a rigid or non-rigid envelope so important, it likewise finally did away with complicated connections between the envelope and the car.
Copyright International Film Service, Inc.
THE BALLOON OF THE U. S. S. OKLAHOMA
From the point of view of car suspension one of the most interesting of the modern French airships is the Astra-Torres. This is a dirigible of the non-rigid type. Canvas partitions are stretched across the interior of the envelope in such a manner as to form a triangle, its apex facing downwards. The sides of this triangle are strengthened by cables and from its apex hang the cables which support the car. The air resistance produced by the cables is therefore very slight, since only two lines are exposed.
Among the aerial war fleets of the Allied nations, the French offers by far the greatest field for study, since it possesses many different types of dirigibles. The Astra and the Astra-Torres are perhaps the chief representatives of the non-rigid design, and are generally considered the most successful of the French airships. The Astra is the older model, and, like the Zodiac, has the long wooden framework or car girder, hung directly to the base of the envelope and distributing to all parts of it the weight of the car. It can be recognized by this and by its stabilizers or small inflated gas bags around the stern of the envelope. The Astra is of medium size, varying in length from 199 to 275 feet. The Astra-Torres is very much longer, those of the 1914 type measuring 457 feet from nose to stern. From the exterior, this airship has a peculiar three-lobed appearance. It tapers very slightly to the stern and is pointed at both ends, but it has not the Astra's inflated stabilizers.
Another French airship of non-rigid design is the Clement-Bayard. It is similar in design and in size to the Astra, but without the inflated stabilizers. Rounded slightly at the nose, the envelope tapers to a sharp-pointed stern.
The Lebaudy is the chief example of a French semi-rigid airship. The envelope is long and cylindrical, pointed at the nose and rounded at the stern, where it is fitted with stabilizing “fins.” The base of the envelope is fitted to a long keel, which ends at the rear in a rudder and fins. From this keel the car is suspended by strong cables, and beneath the car extends a conical structure of steel tubes, with points falling downward. These serve as a protection in case of a sudden landing. In front of the car and on each side of the keel are planes similar to those of an airplane, which help to give balance to the ship.