The Parseval airship was delivered to this country and became known as No. 4; a second ship of the same type was also building when war broke out; needless to say this ship was never delivered. At a later date Messrs. Vickers, who had obtained the patent rights of the Parseval envelope, completed the other two ships of the order.

The Forlanini ship was completing in Italy on the declaration of war and was taken over by the Italians; Messrs. Armstrong had not commenced work on the other two. These ships, although allocated numbers, never actually came into being.


PARSEVAL AIRSHIP No. 4

This airship deserves special consideration for two reasons; firstly, on account of the active-service flying carried out by it during the first three years of the war, and, secondly, for its great value in training of the officers and men who later on became the captains and crews of rigid airships.

The Parseval envelope is of streamline shape which tapers to a point at the tail, and in this ship was of 300,000 cubic feet capacity. The system of rigging being patented, can only be described in very general terms. The suspensions carrying the car are attached to a large elliptical rigging band which is formed under the central portion of the envelope. To this rigging band are attached the trajectory bands which pass up the sides and over the top of the envelope, sloping away from the centre at the bottom towards the nose and tail at the top. The object of this is to distribute the load fore and aft over the envelope. These bands, particularly at the after end of the ship, follow a curved path, so that they become more 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.