nearly vertical as they
approach the upper surface of the envelope. This has the effect of
bringing the vertical load on the top of the envelope; but a greater
portion of the compressive force comes on the lower half, where it
helps to resist the bending moment due to the unusually short
suspensions. A single rudder plane and the ordinary elevator planes
were fitted to the envelope. A roomy open car was provided for this
ship, composed of a duralumin framework and covered with duralumin
sheeting. Two 170 horse-power Maybach engines were mounted at the after
end of the car, which drove two metal-bladed reversible propellers.
These propellers were later replaced by standard four-bladed wooden
ones and a notable increase of speed was obtained.

Two officers and a crew of seven men were carried, together with a
wireless installation and armament.

This airship, together with No. 3, took part in the great naval review
at Spithead, shortly before the commencement of the war, and in
addition to the duties performed by her in the autumn of 1914, which
are mentioned later, carried out long hours of patrol duty from an east
coast station in the summer of 1917. In all respects she must be
accounted a most valuable purchase.

PARSEVAL AIRSHIPS 5, 6 and 7

Parseval No. 5 was not delivered by Germany owing to the war, so three
envelopes and two cars were built by Messrs. Vickers on the design of
the original ship. These were delivered somewhat late in the war, and
on account of the production of the North Sea airship with its greater
speed were not persevered with. The dimensions of the envelopes were
somewhat increased, giving a cubic capacity of 325,000 cubic feet.
Twin Maybach engines driving swivelling propellers were installed in
the car, which was completely covered in, but these ships were slow in
comparison with later designs, and were only used for the instruction
of officers and men destined for the crews of rigid airships then
building.

An experimental ship was made in 1917 which was known as Parseval 5; a
car of a modified coastal pattern with two 240 horse-power Renault
engines was rigged to one of envelopes. During a speed trial, this
ship was calculated to have a ground speed of 50 to 53 miles per hour.
The envelope, however, consumed an enormous amount gas and for this
reason the ship was deflated and struck off the list of active ships.

This digression on Parseval airships has anticipated events som