Designated the ‘C’ class from its anticipated use as a coastal type (‘Coastal’ class was an alternative name), this non-rigid type was of medium size and constructed with a trefoil envelope section, frequently known as the Astra Torrès type. The first of the pattern was ordered in June 1915 from Kingsnorth where it was assembled in the following September. The choice of envelope construction posed problems that were overcome in an interesting manner. Among these was the method of car suspension: the cables for this purpose were attached along the intersection line of the lobes and from here ran through the bottom of the covering to the car. And it is noteworthy that though the gas cells were contained in a non-rigid structure, it was possible to site one of two defensive gun positions on top.

Pembroke was the first naval air station to have the type, and the first flights took place from here in June 1916, other bases being Pulham, Howden. Mullion, East Fortune and Longside. The seas that came under the care of the ‘Coastal’ class airship patrols were those off the Norfolk coast, Lands End, the mouth of the Humber, the Firth of Forth and Aberdeen. Although the work of these vessels was largely unspectacular, one was the subject of an interesting set of experiments which were carried out on 6 September 1916. These were made with the first of the type, C1, in conjunction with the light cruiser HMS Canterbury, and were conducted offshore to look into the question of future developments, whereby an airship might be refuelled from a surface vessel.

A total of only 26 airships of this class were delivered, although these remained in service for lengthy periods. Thus they enjoyed a reputation for longevity as well as for extended flight times, the endurance of the design being as much as 12 hours. The crew of these airships consisted of five men, four of them in the car which also contained the two engines, fore and aft, driving tractor and pusher propellers respectively. The men’s accommodation was very considerably more comfortable than that of the fifth man, the upper gunner who had a special climbing tube through the envelope to reach his lofty position. ‘C’ class airships gave good and reliable service once the problems of cooling for the rear engine and blowing in of the nose cone had been solved.

When engines of differing powers were fitted in any one ship, the more powerful was normally that at the rear, while it is interesting to note that the cars were constructed from a pair of Avro 510 fuselages. Cl alone differed from the others in having a 57.9-in (190-ft) envelope with a 3964.4-cu.m (140,000-cu ft) capacity. The type had small variations of airscoop position and car details.

Four 1916-built Coastal airships were purchased by Russia in 1916, named Chernomor-1, 2, 3 (Name of the character of Russian fairy tale). The envelope volume was 4500 cu.m and the highest speed 80 km / h with two 173 h.p. engines.

In 1916, Chernomor-1 was at the very beginning of the next flight over the Black Sea, when engine failed. When returning to the base, the second engine failed. The situation was complicated by a decrease in the temperature of hydrogen in the envelope, which occurred as a result of the dense cloud covering the sun. The airship began to descend rapidly. The discharge of ballast and heavy equipment did not correct the situation. The gondola collided with water 10 km from the shore near the Kherson lighthouse, a boat coming to the rescue, and towed the airship to the Round Cove. When transporting the airship to the boathouse a strong wind rose, and in order to avoid the danger of damage, Chernomor-1 was dismantled. After that, it was never reassembled.

In one of the Chernomor-2 test flights, one engine failed. It was decided to land at the airfield Kachinskaya Aviation School. When landing, the second engine also failed. Despite this, the landing was done. Due to the increased wind and lack of space for safe parking, the airship “Chernomor-2” was dismantled. After that, it was never reassembled.

In the end, “Black Sea-3” was burned at the boathouse, and the “Black Sea-4” was not completed.

The C-Star class (sometimes written as C* class) of non-rigid airships or “blimps” were used by Britain’s Royal Naval Air Service for convoy escort duties during World War I. Developed from the Coastal class (often referred to as the “C class”), the Star in their designation indicated a modification of the original class which they slowly replaced in service.

The C-Star class were slightly larger than their predecessors. With an endurance of up to 30 hours, and more powerful (and reliable) Renault engines, the C*s had the same basic layout as the Coastal Class, with the same trilobe envelope. However, the envelope tapered towards the rear, as on the SSZ class, which greatly improved stability, as did the larger control surfaces.

Gallery

‘C’ class
Type: sea patrol airship
Powerplant: two 111.9-kW (150-hp) Sunbeam six-cylinder water-cooled piston engines, or one 179-kW (240-hp) Fiat and one 82.0-kW (110-hp) Berliet water-cooled piston engines
Maximum speed 80 kph (50 mph)
Service ceiling 2134 m (7,000 ft)
Useful lift 1608 kg (3,545 lb).
Width 12.04 m (39 ft 6 in).
Length 59.66 m (195 ft 9 in)
Volume 4813.9 cu.m (170,000 cu ft).
Armament: two 7.7-mm (0.303-in) Lewis machine-guns, plus bombs.

Chernomor
Volume: 4,500 cu.m
Max.speed: 80 km/h

C-Star
Powerplant: 1 × tractor-mounted Berliet, 110 hp (82 kW) & 1 × pusher-mounted Fiat, 260 hp (193 kW)
Volume: 210,000 cu ft (6,000 cu.m)
Length: 218 ft 0 in (66.46 m)
Width: 49 ft 3 in (15.01 m)
Height: 57 ft 3 in (17.53 m)
Useful lift: 4,030 lb (1,830 kg)
Maximum speed: 58 mph (93 km/h, 50 kn)
Endurance: at half speed 20 hours; at full speed 10 hours
Service ceiling: 9,500 ft (2,900 m)
Crew: Five