speed of 145 miles per hour. Power plant consists of 4-260
horsepower Maybach Motors totaling more than 1000 H. P.

Zeppelin-Dornier "Dragon Fly" All Metal Flying Boat, 1921.

Carries pilot and two passengers with 60 horsepower motor at a
speed of 80 miles per hour and a gasoline consumption of only
four gallons per hour.]

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

[PLATE 25: 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.

Zeppelin-Dornier "Dragon Fly" All Metal Flying Boat, 1921.

With wings folded greatest width is only 10-1/2 feet.]

That in itself was a remarkable achievement which could have been
accomplished