R38 Class Airship - Design and Development

Design and Development

The R38 class was designed in response to an Admiralty requirement of June 1918 for an airship capable of six days of patrol, at ranges of up to 300 miles from home base, and at altitudes of up to 22,000 ft. Apart from scouting duties, a heavy load of armament was specified, to allow airship to be used for escort duties for surface vessels. The contract for R38 was awarded to Short Brothers, followed by orders for three more ships to the same design. Construction of R38 commenced at Cardington, Bedfordshire in February 1919. Certain modifications to the original design had to be made to allow the R38s to be built within the available construction shed. As a result, two of the power cars were moved up to the sides of the structure to save height, the number of gas bags was reduced from 16 to 14 and there were fewer girder rings around the envelope.

Later in 1919, several airship orders were cancelled as a peacetime economy measure, including the three R38 class ships on which work had not yet commenced: R39, R40, and R41. In a further round of cutbacks, the cancellation of the unfinished R38 also appeared imminent, but before this was actually carried out, the project was offered to the United States in October.

The United States Navy had decided that it wanted to add rigid airships to its fleet and originally intended to get some German Zeppelins as part of the wartime reparations but these were deliberately destroyed by their crews in 1919. An order was placed with the Zeppelin company for a new craft (to be paid for by the Germans) and to go with it they planned to build one in the United States. With the news that the R38 had been cancelled the possibility of buying it was investigated. An agreement was reached in October 1919 for purchase at $2,000,000 and work on the airship recommenced. Changes included a requirement for mast mooring gear, which added a ton to the bows which was then balanced by ballast at the rear. This modification along with the weight savings in the design made a craft that was weak longitudinally. The Germans had made lightweight high altitude Zeppelins towards the end of the war and part of one of these, the L 70, had been recovered from the North Sea after it was shot down in August 1918. However it was not realised that the manœuvrability of these Zeppelins was deliberately restricted, especially in the rate and tightness of turn, due to the lightweight structure.