The rubberized cloth gas cells, or bags, used in 1914 had been discarded for others of light yet strong cotton cloth (and often silk), lined with goldbeater’s skin to make them hydrogen proof.
Many of the experiments were as costly as they were painstaking but the Zeppelin engineers had learned early in their work that airships can not be built satisfactorily without long and arduous experiments to support each innovation. By continually striving to increase efficiency they secured simplified control systems and ships that handled more easily, hulls that were far more rigid yet lighter than their predecessors. Even the framework was lightened as by degrees it was made stronger. Many structural parts were standardized, facilitating production and repairs.
One has an idea of the innumerable parts necessary in the skeleton of a Zeppelin when he learns that more than 250,000 small crossties are required in making the triangular shaped girders in the frame work of a 1,977,300 cubic foot (56,000 cubic meters) ship which crosstie is a masterpiece of construction, because of its ingenious shape and finish.
Eighty-Eight Zeppelins During the War
Few persons know that during the war alone Luftschiffbau-Zeppelin designed and built 88 airships at their four great construction plants, as follows:
| 1914 | 1915 | 1916 | 1917 | 1918 | Total | |
| At Friedrichshafen | 6 | 19 | 14 | 14 | 8 | 59 |
| At Potsdam | 1 | 7 | 8 | — | — | 16 |
| At Staaken | — | — | 2 | 9 | 1 | 12 |
| At Frankfort on Main | 1 | .. | .. | .. | .. | 1 |
| — | — | — | — | — | — | |
| Total | 8 | 26 | 24 | 23 | 9 | 88 |
Zeppelin-Dornier “Dragon Fly” All Metal Flying Boat, 1921.
Wing span, 28 feet, weight empty 858 pounds. Water tight bulkheads are provided in-side fins and wings.
