Engine running pens at Dunsfold airfield

Two brick built jet-engine running pens, c1950, with the eastern example modified c1960 for V/STOL (Vertical/Short Take Off and Landing) testing.

PLAN: the north-western pen is U-shaped in plan, with the curve being to the north and housing an aperture for the former diffuser (a device for dissipating jet engine thrust). The eastern example is also U-shaped but has sliding doors to the south. The pens are accessed from the south, which is where the aircraft would have been reversed in and secured to the ground with its engine facing into the diffuser.

MATERIALS: mixed-stock brick, concrete, steel and steel sheet.

DETAILS:

WESTERN PEN

This pen is a largely open structure, built of brick in an English bond, with regular brick piers supporting the walls which are topped with concrete copping. The walls are approximately 2m deep and 5m high. The main elevation faces north and is semi-circular, with the central section marginally higher than the flanking walls. It has a large ovoid aperture where the diffuser would have been positioned. Above this area is an internal dome like structure faced in aluminium. Either side there are oversized pedestrian door apertures which give internal access to the former diffuser area. The walls either side of the central curved section, extend to the south, and have a number of irregular access doors or apertures. The working space contained by the walls has been adapted to house a late-C20 truck-wash system. The internal face of the brick walls has a regular pattern of inserted black bricks. The flanking walls have single storey brick control rooms, one of which is internal (western side) and the other projects from the wall to the east. They have small rectangular timber casement windows, and flat roofs. The interiors were converted to toilets or rest rooms in the late-C20.

EASTERN PEN

This pen is similar to the north-western example but has been modified to allow testing of V/STOL aircraft. The central section of the north-eastern face is largely open underneath a steel beam which replaced the original diffuser. The walls either side have brick buttresses interspersed along their length, which continue onto the flanking walls. The working space is larger, having been extended to the north-east end. The floor of the pen is largely concrete, but to the north-east end there is a subterranean diffuser pit, which is now covered in metal plate. The inside face of the pen is covered with brushed metal panels, including built-in control rooms to the north-west and south-east. The example to the south-east has a line of small rectangular top-hinged metal windows facing into the working area. There is also a pedestrian door to the control room, which is fitted out with a bench and seating. To the south-west, there is a large double-depth sliding aluminium door, which served as the aircraft entrance.