and transverse frames were composed of girders built up of
three-ply wood, the whole structure being braced in the usual
manner with wire bracings. It had been found in practice with
rigid airships that, if for any reason one gasbag becomes much
less inflated than those adjacent to it, there is considerable
pressure having the effect of forcing the radial wires of the
transverse frames towards the empty bag. The tension resulting
in these wires may produce very serious compressive strain in the
members of the transverse frames, and to counteract this action
an axial wire is led along the axis of the ship and secured to
the centre point of the radial wiring. This method, now current
practice in rigid airship construction, was introduced for the
first time in this ship.

As will be seen from the photograph, the control and navigating
compartment of the ship is contained in the hull, the cars in
each case being merely small engine rooms. These small cars were
beautifully made of wood of a shape to afford the least
resistance to the air, and in number were five, each housing a
single 250 horse-power Rolls Royce engine driving a single fixed
propeller. Here we see another decided departure from our
previous methods of rigid airship construction, in that for the
first time swivelling propellers were abandoned. R 31 when
completed carried out her trials, and it was evident that she was
much faster than previous ships. The trials were on the whole
satisfactory and, except for a few minor accidents to the hull
framework and fins, nothing untoward occurred.

At a later date the whole ship was through fortuitous
circumstances exposed to certain disadvantageous conditions which