Aircraft Hangar No. 6

The Department's description

Exterior description and setting

A large , modern looking , aircraft hanger located near the entrance to RAF Aldergrove,Co. Antrim. The roof and sides of the structure are finished in plastic coated steel cladding. The western side is largely taken up with a set of large modern full height sliding doors.

Historical information

Built in 1920 as a remodelling of a very much larger structure which was originally built in 1918 but which was substantially destroyed in a hurricane in 1920.

The original building measured approximately 167 m x 45 m and was open along its west side, and roofed with timber ‘Belfast’ trusses. Following the hurricane which partly destroyed the building in 1920 the site was reconfigured as a number of smaller buildings, only one of which continued to be used as a hangar.

The trusses for the original roof were supplied by Harland and Wolff (the shipbuilders); it is not known whether they were fabricated on site or transported from the shipyard, some 32 km away. Parallel chord steel trusses supported the timber trusses over the door openings. For a history of the Belfast Roof Truss - see HB18/08/139.

Aldergrove is the oldest airfield in Northern Ireland. It was selected by the R.A.F. in 1917 as a possible site for a pilot training school, but was actually developed as an Aircraft Acceptance Park by Harland and Wolff under the auspices of the Air Ministry in 1918 for the purposes of assembling and test-flying Handley-Page V155 bombers. Its use as an A.A.P. came to an end in December 1919, following which the R.A.F. continued to maintain the base for training exercises.

References – Primary Sources
1. OS Map 1920, Co Antrim 55.
2. Photographs in the Harland and Wolff collection exhibited at the Ulster Aviation Society Heritage Centre, Langford Lodge.
Secondary Sources
1. D.J. Smith, Action stations 7: military airfields of Scotland, the North-East and Northern Ireland (Cambridge, 1983), p 29.
2. M. Moss and J.R. Hume, Shipbuilders to the world: 125 years of Harland and Wolff, Belfast, 1861-1986 (Belfast, 1986), pp 199-200.
3. D.J. Smith, Britain’s military airfields, 1939-45 (Wellborough, 1989), p 10.
4. R Gilfillan & S Gilbert. 'The 'Belfast' Roof Truss - Worth Conserving?', Journal of Architectural Conservation, No 1, Vol 9 (March 2003), pp 45-56. This article includes a photograph of the roof of this building under construction.
5. M Gould. “A Historical perspective on the Belfast Truss Roof”, ‘Journal of Construction History’ (2001)

Criteria for listing: architectural interest

A. Style
B. Proportion
D. Plan Form
F. Structural System

Criteria for listing: historic interest

W. Northern Ireland/International Interest
V. Authorship
Z. Rarity

Evaluation

The hanger, though extensively refurbished , is considered to merit listing because it provides a surviving example of the use of the "Belfast" roof truss, a particular design of timber truss developed around the mid-nineteenth century to meet the demand for efficient, lightweight and longer roof spans brought about by the industrial revolution.It was a very efficient structural form with a curved top member that behaves essentially as an arch in combination with a horizontal tie member.