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C - D Test-Stands and Support Structures, Former Royal Ordnance Establishment, Westcott, Aylesbury Vale

Description: C - D Test-Stands and Support Structures, Former Royal Ordnance Establishment, Westcott

Grade: II*
Date Listed: 23 May 2013
Building ID: 1403962

OS Grid Reference: SP7110016607
OS Grid Coordinates: 471100, 216607
Latitude/Longitude: 51.8435, -0.9693

Locality: Aylesbury Vale
Local Authority: Aylesbury Vale District Council
County: Buckinghamshire
Postcode: HP18 0XB

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Listing Text


C-D site at SP 71089 16600, liquid propellant test stands and ancillary buildings, 1947 with subsequent alterations and additions.

Reason for Listing

C-D site, containing two liquid propellant (nitric acid) test stands dating to 1947, and support structures at the Westcott former Royal Ordnance Establishment, is listed at Grade II* for the following principal reasons:
* Date: the earliest surviving test stands (with A-B site, Westcott), in the United Kingdom;
* Rarity: one of only three sites nationally (the others being A-B and P sites, Westcott) where 1940s test stands survive;
* Technological interest: a site which was initially used to test motors for the Blue Slug anti-ship missile as well as other missile programmes and, in the case of D stand, which was later used for satellite testing;
* Form: the form of the test stands allows an understanding of the perilous nature of the oxidant and fuel and the special handling requirements to enable testing;
* Intactness: C stand is the most intact of the four early stands and thus best reflects the primary form of British test stand design;
* Historic Interest: a site which represents the pioneering post-war collaboration between British and German scientists in the development and testing of liquid propellants. D-stand has added historic interest as the site of a fatal explosion in late 1947 which was to significantly alter the form of all subsequent test stands;
* Group Value: with A-B site at Westcott, representing the primary 1940s stands at the site. Also group value with later test stands, including those for solid propellants. Westcott is the most significant site nationally for rocket propulsion research and development and the test stands collectively express through their form the technological advances of the second half of the C20 in this field.


Westcott has been synonymous with rocket research and development since the mid 1940s. The Second World War saw this work take on a new urgency given Germany’s success in developing the devastating V1 and V2 missiles. After the cessation of hostilities, the importance of German rocket research was fully realised and incorporated into British programmes. The Guided Projectile Establishment opened at Westcott in 1946 and, until 1948, German scientists, classed as special internees, were relocated there to continue their research into liquid propellants alongside their British counterparts. Early research concentrated on liquid bipropellants for rocket engines (using liquid oxygen, hydrogen peroxide and nitric acid oxidisers) with solid propellant research beginning in 1949 (using solid fuels such as extruded cordite and plastic propellants).

In the early post-war years and renamed the Rocket Propulsion Department of the Royal Aircraft Establishment (RAE), Westcott continued research into liquid propellants alongside the Waltham Abbey experimental station. In the early 1950s all work connected with this programme was transferred to Westcott as the large remote site with its specialised and purpose-built facilities allowed rockets to be tested and fired, although not launched.

In the late 1950s the liquid propellant motor for the Blue Streak missile (the RZ2) was developed at Westcott and went on to be used in the Europa-1 space rocket launch vehicle. Naming most of their rocket motors after birds the scientists at Westcott developed many successful engines which were used variously in upper atmosphere research programmes (the Raven) and for the Black Knight research rocket testing re-entry into the earth’s atmosphere (the Cuckoo). Smaller missile programmes were designed and built in Westcott between the 1960s and 1980s including Blowpipe and Seawolf. Large missile programmes, such as Polaris in the 1960s and Chevaline in the early 1970s, were also developed there and are perhaps more widely known. In 1977 Westcott and the Waltham Abbey research station were merged to form the Propellants, Explosives and Rocket Motor Establishment.

Westcott remains at the forefront of liquid propellant rocket motor research and development with, for example, its LEROS liquid engine used in the Mars missions of the late 1990s.

C-D site
Colloquially known as the 'German Emplacements' A-B and C-D sites house the earliest test stands at Westcott. Layout drawings of September 1946 and design drawings for bi-fuel emplacements of January, February and March 1947 are held in the Westcott archives. They were collectively designed for the horizontal testing of liquid-fired motors using kerosene and hydrogen peroxide. Both sites were built in 1947, and thus in the very earliest days of the establishment of the research facility, to test liquid propellant rocket engines. Aerial photographs of April and June 1947 show them under construction with stands B and D further advanced than their pairs although the traverses for A and C are clearly visible. These test stands were initially built as matching pairs on the two different sites, thus A and D were of the same design, as were B and C. A-B site housed hydrogen peroxide test stands whereas C-D site used nitric acid and it is for this reason that two seemingly identical test stands were built at the same time.

Immediately after the Second World War A-B and C-D sites were associated with German engineers. Two of the key German scientists who worked at Westcott were Dr Johannes Schmidt and Walter Reidel. Schmidt formerly worked at the Walther Werke in Kiel, a firm specialising in the use of hydrogen peroxide as rocket oxidisers; a technology that was later developed in Britain and used in the British Black Knight and Black Arrow programmes. Riedel had worked with some of the key figures in the German rocket programme including Walther Dornberger and Werner von Braun on the V2 project and its precursors at Kummersdorf and later Peenemünde. Others came from Trauen, which, after the war, came under the Ministry of Supply in order to exploit wartime German technology. These German engineers had a significant impact on the direction of British rocket technology in the late 1940s and early 1950s.

C-D site was used to test rocket motors that used nitric acid as an oxidant. These included, in the late 1940s, motors which went into a liquid propellant variant of the Sea Slug missile known as Blue Slug (an anti-ship missile powered by an NK-1 motor) and various other missiles.

On November 14 1947 there was a fatal accident at test stand D when a German rocket-assisted take-off unit exploded on testing, killing two British technicians (Mr R P Rowlands and Mr J A Salmons) as well as Dr Johannes Schmidt, the leader of the German team. A possible cause of the explosion was identified as split piping from the petrol and hydrogen peroxide tanks (which were transported to the motor combustion chamber and mixed there) caused by vibration in the combustion chamber which allowed the oxidiser to leak. Schmidt is understood to have been beheaded by the plate-glass observation window which had been incorrectly installed. The others drowned following the severance of the water main. A photograph in the site archive, dated 14-11-1947, shows D-stand following the explosion in which the severity of the damage is evident: the force of the blast has buckled and pushed up the roof, pushed out the eastern wall of the test chamber (pushing it into the adjoining test chamber), and has also broken the observation window to the west. This accident was important in influencing the form of all subsequent test stands such that the safety of the stand personnel was dramatically improved; primary modification generally being the removal of direct vision between them and the rocket under test.

The architectural and historical evidence suggests that the explosion at D had an impact on the other three stands in this group. It is not clear from the available evidence whether test stand A had been completed by November 1947. If so then it was clearly rebuilt after the accident with separate control and monitoring rooms (drawing reference EB 207/2, 27 Jan 1949, Westcott Archive) and it also has no observation windows. Alternatively, its design could have been modified during construction to reflect the lessons learned. Its current form, with a physical separation between the control/observation room and firing bay is also seen at D. Test stands B and C remained largely in their original form although with modified observation windows, C less so than B as it only had two periscopes inserted. D stand had to be re-built also as contemporary photographs and plans (in the Westcott site archive and The National Archives) show that the east wall of the westerly bay and its roof were blown out of line.

D stand was later used for the pressure testing of satellites and is still (2012) a functioning test stand. C stand is redundant. Between the two stands are buildings 209, 360 and 360A, also 51 to their south. Building 209 is the original (1947) support workshop for the stand. It is now redundant, as is Building 360, a later (post-1952) test observation/recording building. Buildings 360A and 51 are not of special interest.


MATERIALS: reinforced concrete, brick, earth traverses.

DESCRIPTION: C-D site contains a pair of test stands each with their protective earth traverses to the north and a contemporary fuel management system. D stand is to the west and C stand to the east. To the south of the stands is Building 209 which is the contemporary support workshop and between D and C lies Building 360.

C TEST STAND (also known as Building 208) is the more modest of the two stands on site and was originally the pair of B stand at Westcott. It has two mirror-image firing bays to the north with ceiling gantries and original direct observation windows, brick control/observation rooms to either side and oxidant and fuel tank chambers are to the rear (south), as at B. Of the group of four early test stands at Westcott (A, B, C, D) it is the most original in terms of physical structure, exhibiting the pre-November 1947 design. There is a later single periscope inserted through one of the observation windows to each firing chamber. The control panels are also later, of 1960s to 1980s date, and some of its fittings have been removed. There is an earth traverse to the north and drains and tanks to both north and south.

D TEST STAND (also known as Building 207) was originally the pair of A stand. It is still used for testing and therefore has a more recent superstructure of heavy chain mail, torpedo netting to the front (north) which was added in the last decade or so. As at A there are physical gaps between the control rooms and firing bays. There are no ceiling gantries as these, and some other fittings, have been removed to allow its current test use. The circular periscope hatches remain. There are tanks and run-off channels to the north and south, although some to the north have been backfilled, and also an earth traverse to the north. As at A stand, the oxidant was stored to the sides and the fuel to the rear. The control rooms (to the west and east) are of reinforced concrete except for a shield wall to the east which is partly in brick. The control room doors are truly massive, undoubtedly inserted as a reaction to the November 1947 accident and there are additional square escape hatches.

ANCILLARY BUILDINGS: the main and original workshop for these stands is Building 209 which is a prefabricated building, constructed of modular panels, with a pitched corrugated roof and metal multi-paned casements. There is a flat-roofed concrete porch at the south-east corner. Between the two stands is a small flat-roofed building (Building 360). In red brick English bond it has metal-framed casements with concrete cills and heads and an observation window to the north.

Listed building text is © Crown Copyright. Reproduced under licence.