R31-class airship

The R31 class of British rigid airships was constructed in the closing months of World War I and comprised two aircraft, R31 and R32. They 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. R31 was the largest British airship to fly before the end of the war, and the class remains the largest mobile wooden structures ever built

As the airships were intended for fleet protection operations, they were to be fitted with defensive machine guns on top of the envelope, at the stern and in the gondolas. A 12-pounder gun was to be fitted in a special position centrally below the airship for use against U boats. In the event, this armament was only fitted to R31, as R32 was only completed after the armistice. 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 on either airship.

Operational history

R31

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; and R32 was built in this five-engine configuration from the outset.

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 girders 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.

R32

After being formally accepted by the Royal Navy, the R32 made her first trial flight on the 3rd September 1919 and then on the 6th September went to the base at Pulham Market, Norfolk. On the 10th September in formation with the R33 she made a flight over the Netherlands, Belgium and Northern France and back to Pulham. In October 1919 the R32 with the rest of the airship fleet was formally handed over to the Royal Air Force. There then followed a period when the airship was used by the National Physical Laboratory for structural testing. On the 20th March 1920 she was flown to the base at Howden, East Yorkshire, to be refurbished and used for crew training by the American party who had come to accept the R38 (ZR-2). When the metal-framed R80 became available, the use of the by now obsolete wooden-framed R32 stopped and, to save money, she was decommissioned and used to assess the effect of a gas bag bursting. The covering was removed and the engines taken away and cell 18 overpressurised until the expansion caused the bracing and structure to fail. The frame was then dismantled.

In all the airship had logged just over 212 hours in the air, of which 203 hours were under the control of Commander LH Maxfield and his fellow Americans.

Specifications (five engines)

General characteristics Performance

References

• R31 on the Airship Heritage Trust website
• R32 on the Airship Heritage Trust website