Editing R38-class airship (section)

==Design and development==
The ''R.38'' 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&nbsp;ft (6,700&nbsp;m).<ref name=aht/> 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.<ref name =Swinfield78>Swinfield 2012, p. 78</ref> 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 [[nationalization|nationalised]].<ref>Higham 1961, pp. 204–205.</ref> Construction of ''R.38'' started at Cardington in February 1919.  It was intended to follow ''R.38'' with orders for three airships of the same class: ''R.39'', identical to ''R.38'', to be built by [[Armstrong-Whitworth]], and two others, ''R.40'' and ''R.41'', of a design variant with the length reduced to 690&nbsp;ft (210.31&nbsp;m) due to the limited size of existing manufacturing sheds.<ref>Higham 1961, p. 207.</ref> The Armistice coupled with the assignment of airships from the admiralty to the Royal Air Force and a decision to nationalize the Shorts airship plant into the Royal Airship Works confused the matter of whom was responsible for what. Constructor-Commander Campbell became both Manager and Chief Designer of the Royal Airship Works.<ref>Jamison 1994, p. 57.</ref>

Later in 1919, several airship orders were cancelled as a peacetime economy measure, including the three planned ''R.38'' class ships.<ref name=aht/> In a further round of cutbacks, the cancellation of the unfinished ''R.38'' also appeared imminent, but, before this actually happened, the project was offered to the United States. The United States Navy demanded significant changes in the airship including modification to the bow in order to allow mooring to a mast, access to the mast from the keel and the addition of weight to the stern to ensure balance.<ref>Douglas H. Robinson, and Charles L. Keller. "Up Ship!": U.S. Navy Rigid Airships 1919–1935. Annapolis, Maryland: Naval Institute Press, 1982, p. 34</ref>

The hull contained 14 hydrogen-filled gasbags.  The 13-sided mainframes were {{convert|15|m|ft|order=flip|abbr=on}} 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.<ref>Robinson 1973, pp. 168–169</ref>