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The ''R38'' class (also known as the ''A'' class) of rigid airships was designed for Britain's Royal Navy during the final months of World War I, intended for long-range patrol duties over the North Sea. Four similar airships were originally ordered by the Admiralty, but orders for three of these (''R39'', ''R40'' and ''R41'') were cancelled after the armistice with Germany and ''R.38'', the lead ship of the class was sold to the United States Navy in October 1919 before completion. On 23 August 1921, ''R-38'' was destroyed by a structural failure while in flight over the city of Hull. It crashed into the Humber estuary, killing 44 out of the 49 crew aboard.〔 "Entry includes considerable details about the ship, flight, and crash."〕 At the time of her first flight she was the world's largest airship.〔(【引用サイトリンク】title=R38/ZR2 )〕 Her destruction was the first of the great airship disasters, followed by the US airship Roma in 1922 (34 dead), the French Dixmude in 1923 (52 dead), the British R101 in 1930 (48 dead), the USS Akron in 1933 (73 dead), and the German Hindenburg in 1937 (36 dead). ==Design and development== The ''R38'' class was designed to meet an Admiralty requirement of June 1918 for an airship capable of patrolling for six days at ranges of up to 300 miles from home base and altitudes of up to 22,000 ft (6,700 m).〔 A heavy load of armaments was specified, to allow the airship to be used to escort surface vessels. Design work was carried out by an Admiralty team led by Constructor-Commander C. I. R. Campbell, of the Royal Corps of Navy Constructors.〔Swinfield 2012, p. 78〕 The construction contract was awarded to Short Brothers in September 1918 but cancelled on 31 January 1919 before work had been started. It was then re-ordered on 17 February: on the same day Oswald Short was informed that the Cardington, Bedfordshire works, recently built as a specialised airship production facility, was to be nationalised.〔Higham 1961, pp. 204–5.〕 Construction of ''R38'' started at Cardington in February 1919. It was intended to follow ''R.38'' with orders for three airships of the same class: ''R39'', identical to ''R38'', to be built by Armstrong-Whitworth and two others ''R40'' and ''R41'', of a design variant with the length reduced to 690 ft (210.31 m) due to the limited size of existing manufacturing sheds.〔Higham 1961, p. 207.〕 Later in 1919, several airship orders were cancelled as a peacetime economy measure, including the three ''R38'' class ships.〔 In a further round of cutbacks, the cancellation of the unfinished ''R38'' also appeared imminent, but before this actually happened the project was offered to the United States. The hull contained 14 hydrogen-filled gasbags. The 13-sided mainframes were apart and were made up of diamond-shaped trusses connected by 13 main and 12 secondary longitudinal girders and a trapezoidal keel. There were two secondary ring frames between each pair of mainframes. The forward-mounted control car was directly attached to the hull. The cruciform tail surfaces were unbraced cantilevers and carried aerodynamically balanced elevators and rudders. The six Sunbeam Cossack engines, each driving a two-bladed pusher propeller, were housed in individual cars arranged as three pairs: one pair aft of the control car. one pair amidships and the third pair aft.〔Robinson 1974, pp. 168–9〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「R38-class airship」の詳細全文を読む スポンサード リンク
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