The type was to have a speed of , carry a crew of two, of bombs,
wireless equipment, fuel for eight hours flying, and capable of reaching an altitude of . Most importantly the design had to be simple, in order to ease production and to facilitate training of the crews, since the new airships, designated the "Submarine Scout" or "Sea Scout" (SS) class, needed to be operational within weeks rather than months. and was effectively a
B.E.2c aeroplane fuselage and engine minus wings, tailfin and elevators, slung below the disused envelope from airship
HMA No. 2 (Willows No. 4) that had been lying deflated at the
Royal Aircraft Establishment (RAE),
Farnborough Airfield. It was ready for evaluation trials within a fortnight of approval being granted for the scheme, and on 18 March 1915 the first SS class airship entered service. The whole process had taken less than three weeks, and voicing his approval, Admiral Fisher made the famous comment: "Now I must have forty!" Each of the SS versions used similar envelopes that were composed of four layers: two of rubber-proofed fabric with a layer of rubber between them, and a further rubber layer on the inner, or gas surface. The external surface had five coats of
dope applied to it to protect it from the elements and to render the envelope completely gastight. The first two coats were of "Delta dope" (a flexible dope used for the first time in 1913 on the British Army
semi-rigid airship Delta), followed by two of aluminium dope and finally one of aluminium varnish. To stiffen the nose of the envelope and to prevent it blowing in, 24 canes were arranged radially from its centre and covered with an aluminium cap.
Planes The original design featured four fins (or planes) and rudders set radially to the envelope: two horizontal fins, and two below the envelope in an inverted
V-tail configuration; however, in some cases the two lower fins were replaced with a single central fin that carried a larger rudder. The fins were identical in size and shape, and were constructed of
spruce, aluminium, and steel tubing, braced with wire and covered with doped fabric. and the armament consisted of bombs carried in frames suspended about the centre of the undercarriage and a
Lewis Gun mounted on a post adjacent to the pilot's seat. The bomb sight and release mechanism were located on the outside of the car on the
starboard side of the pilot's position.
SS Maurice Farman The Airships Ltd. design initially used , and later envelopes. Dual controls were fitted for the pilot and the observer/wireless operator. Occasionally a third seat was fitted to carry a passenger or an engineer. Renault engines were normally fitted, mounted at the rear of the car in
pusher configuration, but a
Rolls-Royce Hawk proved effective in one instance. The type was slightly slower than the SS B.E.2c, but the cars were roomier and more comfortable.
SS Armstrong Whitworth The version fitted with the Armstrong Whitworth
F.K. car was similar in many respects to the B.E.2c type, but had a single-skid landing gear with buffers, and required the larger envelope to maintain a reasonable margin of lift. A water-cooled
Green engine was fitted in
tractor configuration, and fuel was carried in two aluminium tanks supported in fabric slings suspended from the envelope, saving in weight compared to the internal tanks fitted to the B.E.2c.
Airship stations At the same time a number of new air stations were set up as well as a training station at
Cranwell. The
rigid airship programme was also gathering momentum, and these stations were later joined by several more that together formed a chain all around the UK coast. ==Production==