Building 75 (C-Type Hangar), Aircraft Storage Unit Site

Aircraft Storage Shed, Built 1938

This C-type hangar was designed by A. Bulloch, architectural adviser to the Air Ministry's Directorate of Works and Buildings, under Drawing No 4637/35. It is constructed of Bath stone ashlar on concrete or block foundations, with steel stanchions and roof framing, and asbestos slate roofs.

The hangar comprises 12 bays with annexes along the side walls containing a crew room, locker room, armament store, ground equipment rooms, offices and workshop accommodation.

At each end are six full-height steel doors with paired full-width lights at the top, fitted to overhead sliding gear but without gantries. Above the doors is a deep apron clad in asbestos slate. Each end has a one-bay return with parapet taken to this same height. The remaining 10 bays have a lower parapet above a continuous range of paired lights in 4 by 4 large panes, protected externally by later-added translucent corrugated sheeting. The parapets conceal the series of hipped roofs.

The side walls are lined with low, flat-roofed single-storey annexes. These are fitted with 2 and 3-light steel casements with horizontal bars, the windows grouped under lintel bands, with central doorways.

Internally, the principal trusses are set to the right-lines of the multiple roofs, formed from paired small channels connected by flat zig-zag bracing or flat plating, with main bracing of flats or angles. A complex of cross members at two levels is carried to horizontal chords at mid-bay. Lateral support and bracing is provided in the outer wall planes above the window strip. The end bays have wind-bracing in the horizontal plane at door-head height. The roof slopes are underlined with fibre-board insulation.

The Type C hangar, of which 146 sheds were built on 72 sites, was the standard hangar of the post-1934 RAF expansion scheme. It was designed with a span of 150 feet (45.7 metres) and a length of 300 feet (91.4 metres). Bulloch's first designs displayed assured handling of the functional and aesthetic challenges these large sheds posed, with Moderne influences particularly strong in the handling of the end bays and the massing of the workshop blocks to the rear of the repair hangar.

Hullavington opened on 6 June 1937 as a Flying Training Station. In 1938 it was selected as one of a series of Aircraft Storage Units for storing vital reserves destined for the operational front-line. The hangars at Hullavington, by virtue of their degree of preservation and the use of local limestone, present themselves as the finest architectural assemblage of aircraft hangars of the inter-war period. This building comprises part of a remarkably complete technical group, established to the north of the main group, providing repair and administration facilities to the Aircraft Storage Unit. Hullavington is in every respect the key station most strongly representative of the improved architectural quality characteristic of air bases developed under the post-1934 RAF expansion.