R31-class airship

The R31 was a British airship that first flew in July 1918.

History

The R31 and her sister ship the R32 were designed by the Royal Corps of Naval Constructors – with assistance from a Herr Müller who had defected to Britain and previously worked for the Schütte-Lanz airship company – and built by Short Brothers at the Cardington airship sheds. The airship frame was made from spruce plywood laminated into girder sections and weatherproofed with varnish and also fireproofed. These enclosed 21 gas bags.

As the airship was intended for fleet protection operations it was fitted with defensive machine guns on top of the envelope, at the stern and in the gondolas. A 12-pound cannon was fitted in a special position centrally below the airship for use against U boats. It had also been intended to fit a bomb load of two 520 pound bombs and four 230 pound bombs but with the end of hostilities these were never installed.

The R31 made her first trial flight of two hours in July 1918 under the command of Squadron Leader W.C. Hinks. A top speed of 70 mph was achieved: well above the expected 50-55 mph and faster than any other airship then in service. She was originally powered by six 275 hp Rolls-Royce Eagle engines but in view of the performance and to reduce fuel consumption one was removed, reducing the maximum speed to a still satisfactory 65 mph.

The airship was finally commissioned on 6 November 1918, just before the armistice, after having spent four hours in the air. She set off again under the command of Squadron Leader Hincks for the airship base at East Fortune in Scotland. On the journey she encountered bad weather and it was feared that some of the plywood girder were failing, so she diverted to the airship base at Howden, East Riding of Yorkshire, for examination and repair. Unfortunately, the sheds had not been repaired after the R27 caught fire and the roof in particular leaked badly. This caused the glue holding the plywood together to deteriorate; as a result, the airship became un-airworthy and in February 1919 she was dismantled. The covering was removed and returned to Cardington and the frames sold for £200. As a final irony, these were broken up and sold for firewood but, because of the fireproofing treatment, they would not burn.

Specification

• Length: 615 ft
• Diameter: 65 ft 6 in
• Speed: 70 mph (later 65 mph)
• Engines: 6 (later 5) x Rolls-Royce Eagles of 275 hp each
• Volume: 1,547,000 cubic feet
• Disposable lift: 16.5 tons