the hull.
The horizontal fins were of similar design and attached in a like
manner to the hull. Triplane rudders and biplane elevators of the box
type were fitted in accordance with the German practice of the time.
Auxiliary biplane rudders were fitted originally abaft the after car,
but during the first two trial flights they proved so very
unsatisfactory that it was decided to remove them.

Two cars or gondolas were provided to act as navigating compartments
and a housing for the engines, and in design were calculated to offer
the least amount of head resistance to the wind. The cars were
composed of duralumin girders, which formed a flooring, a main girder
running the full length of the car with a series of transverse girders
spaced in accordance with the main loads. From each of these
transverse girders vertical standards with a connecting piece on top
were taken and the whole exterior was covered with duralumin plating.
The cars were suspended in the following manner. Two steel tubes
fitting into a junction piece at each end were bolted to brackets at
the floor level at each end of the transverse girders. They met at an
apex above the roof level and were connected to the tubing of the keel.
In addition, to distribute the weight and prevent the cars from
rocking, steel wire suspensions were led to certain fixed points in the
hull.

Each car was divided into two parts by a bulkhead, the forward portion
being the control compartment in which were disposed all instruments,
valve and ballast controls, and all the steering and elevating
arrangements. Engine-room telegraphs, voice pipes and telephones were
fitted up for communication from one part of the ship to the other.
The keel could be reached by a ladder from each car, thus providing
with the climbing shaft through the hull access to all parts of the
ship.

The original engine equipment of No. 9 was composed of four
Wolseley-Maybach engines of 180 horse-power each, two being installed
in the forward car and two in the after car. As the ship was deficient
in lift after the initial flight trials had been carried out, it was
decided to remove the two engines from the after car and replace them
with a single engine of 250 horse-power; secondly, to remove the
swivelling propeller gear from the after car and substitute one
directly-driven propeller astern of the car. This as anticipated
reduced the weight very considerably and in no way lessened the speed
of