The Giant Biplane had a wing spread of 137.76 feet and carried
a useful load of 41/2 tons. Its power plant totaled 1250
horsepower and made a speed of 90 miles per hour.

Zeppelin-Dornier All Metal Pursuit Plane Type DO D1, 1918.

Note the absence of all struts and wire bracing.]

During the summer of 1918 the Zeppelins were again given higher climbing
ability to meet the ever-increasing efficiency of planes and
anti-aircraft guns. Another gas bag was added to the new ships (Plates
13 and 14), which brought them up to 2,189,220 cubic feet (62,000 cubic
meters) capacity. In order not to diminish the speed two motors were
added in respective gondolas, making seven engines in all, aggregating
1820 horsepower. They could carry 94,798 pounds (43,000 kilograms) or
about 60% of their total lift. It was planned to add improvements
enabling them to reach an altitude of 26,240 feet (8,000 meters) but the
armistice halted all military activities and there was no occasion at
that time for commercial craft to fly so high.

The Most Remarkable Scientific Development in the History of Aeronautics

Looking back over the development of the Zeppelins (Plate 15), one fails
to find such remarkable and quick advance in any other medium of
transportation. The history of engineering does not record in any other
science progress comparable to that of the relatively new science of
lighter-than-air as represented by the Zeppelins during the four years
of war.

Seventy Percent Speed Increase

Their speed had increased from 46.6 to 87.5 miles per hour (75 to 130
kilometers per hour) approximately 70%. Their horsepower averaged 2,000.
To carry useful loads of 44 tons their hydrogen capacity had been raised
from 706,200 to 2,189,220 cubic feet (20,000 to 62,000 cubic meters).
Other commercial ships were built embodying the improvements developed
during the war. A description of them will be found in Chapter
III.

Refinement in Design

This progress was made possible only by continuous experiments. Ideas
and suggestions were adopted regardless of expense or chance of failure.
In this way the Zeppelins had the advantage of every conceivable
refinement in design. Their hulls, motor gondolas, in fact, all braces
and wires were streamlined so as to offer the least air resistance.

[PLATE 24: Zeppelin-Werke Staaken "Giant" All Metal Monoplane.

Which carried eighteen passengers in a luxurious cabin at a