A-B site at SP 71372 16472, liquid propellant test stands and ancillary buildings, 1947 with subsequent alterations and additions.
Reason for Listing
A-B site, containing two liquid (hydrogen peroxide) propellant 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 C-D site Westcott), in the United Kingdom;
* Rarity: one of only three sites nationally (the others being C-D and P sites, Westcott) where 1940s test stands survive;
* Technological interest: a site where early and significant research and development took place relating to the Blue Streak (and subsequently Europa 1 orbital programme), Polaris and top-secret Chevaline missiles;
* 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. B stand also remains as fitted out for the Chevaline programme;
* Historic Interest: a site which represents the pioneering post-war collaboration between British and German scientists in the development and testing of liquid propellants;
* Group Value: with C-D 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.
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 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 initally 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 sites 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.
Details of the early programmes undertaken at A stand are currently unknown, but in 1949, B stand began testing the Beta research rocket motor. This stand was in continuous use until the 1980s. One of its last tasks was the development of the manoeuvring motors for the Chevaline missile warhead and the stand remains as fitted out for the Chevaline tests according to a former employee. In the mid-late 1970s A Stand was also used for the Chevaline warhead project and the surrounding high fence is a relic of the high security status of the area at that time. From 1954 onwards the building to the rear (south) of A and B stands, Building 276, was used for the development and testing of the Blue Streak missile 1/60th scale model silo, the footings for which are still visible. Building 14 (not included in the listing), which dates to the 1960s and was a filling workshop for Chevaline development, is understood to have also been used for preparing Polaris engines.
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. 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.
The main and original (1947) workshop for the site is Building 276 located to the south of the test stands. There is also a further support workshop, Building 253, which is also believed to be of the primary construction phase.
Building 432 is a support workshop which housed instrumentation for the test stands. It is not shown on an aerial photograph of 1952 and so is of mid-1950s or later date. To its south is the site where the 1/60th Blue Streak Model Silo was built and tested. This was a Perspex model mounted on a lathe bed so only the concrete footings for the latter remain. Prior to the construction of the model, earlier tests had taken place in the adjacent Building 276.
MATERIALS: reinforced concrete, brick, earth traverses.
DESCRIPTION: A-B site contains a pair of test stands each with their protective earth traverses to the north and a contemporary fuel management system. B stand is to the west and A stand to the east. To the south of the stands is Building 276, the contemporary support workshop. This is protected by a traverse to its north. Building 432 lies between the stands, Building 253 is to the south-west of B stand and all other surviving buildings are in a group in the south-west corner of the site.
A TEST STAND: A stand (also known as Building 251) was originally the pair of D stand at Westcott. It has two mirror-image firing bays to the north, each with its own control/observation room to the south-west and south-east. There are physical gaps between each control room and its firing bay, which must be a post-November 1947 modification, as are the periscopes which allow observation of the test as the original steel windows have been removed. There are external pipes which provide fresh air into the control rooms and a bath tub at the north-east corner of the stand. Some of the fittings such as electrics and ducting are more recent additions, but original features such as a ceiling gantry for lifting motors into position, survive. The oxidant is stored to the sides and the fuel to the rear of the stand. A later modification of circa 1970 was the addition of a large liquid hydrogen (fuel) tank to the far west of the stand. There is an earth traverse to the north and drainage runs and settling tanks to the north and south.
B TEST STAND: B stand (also known as Building 250) is smaller and of a simpler form in its design and layout than A stand and was originally the pair of C stand at Westcott. It has paired firing bays to the north and related control/observation rooms. This stand retains its steel windows and therefore survives in a more original form than A although the reinforced concrete armour plated observation rooms were modified, and strengthened post-November 1947. The stand's pipework has also been replaced and now reflects, in form, its Chevaline testing incarnation. The chambers for the fuel and oxidant tanks are at the rear (south). There is an earth traverse to the north and drainage runs and settling tanks to the north and south.
ANCILLARY BUILDINGS: Building 276 is located to the south of the stands and is protected by a traverse, a feature which is unique, in the protection of a workshop, to this stand. It is a prefabricated building, of modular panel construction on a 6 foot frame, with a pitched roof and metal casements and is in a somewhat dilapidated condition. To the south-west of B stand is a further support workshop (Building 253). It is also prefabricated, modular and has a pitched corrugated roof and some original multi-paned metal casements.
Building 432 is a support workshop. It is an L-shaped flat-roofed red brick building in English bond, located between the two test stands. To its south are the concrete footings for the 1/60th Blue Streak Model Silo construction and testing.
Listed building text is © Crown Copyright. Reproduced under licence.