As Vickers turned its attention to civil aviation after the Second World War, Barnes Wallis, famous for his wartime work on ‘bouncing bombs’, was made head of a new Research and Development department.
Wallis knew that demanding tests would be required to realise his ‘grand vision’ for efficient long-range air transport, capable of flying non-stop from the UK to Australia. To achieve this, Wallis persuaded Vickers to design and build a high altitude and climatic test chamber, which became known as the Stratosphere Chamber, at Brooklands.
The major design features of the Chamber were:
- Length of interior: 50 feet (15 metres)
- Diameter of interior: 25 feet (7.5 metres)
- Total enclosed volume: 40,000 cubic feet (11,135 cubic metres) (including circulation ducts)
- Atmospheric pressure: sea level to 70,000 feet (21,336 metres) or 1/20th Atmosphere (0.05 bar)
- Temperature: -65˚C to +55˚C
How it works
To simulate atmospheric conditions at 70,000 feet (21,000 metres), air was extracted from the Chamber by a number of vacuum pumps to reduce the pressure to 1/20th of that at sea level. The adjoining refrigeration plant cooled ammonia and methanol gases, which were then circulated through 16 heat exchangers, located at each corner of the four air ducts to cool the Chamber.
Climatic conditions such as snow and ice were created by spraying water into the Chamber over the test objects, and gale force winds of up to 40 knots (74km/h) were produced by the giant fans in the air circulation ducts. The other end of the environmental scale could be simulated just as easily. Heating was supplied by banks of 200kW heaters so that dry or humid heat could be produced at will. In addition, infra-red and ultra-violet light could be used to simulate solar radiation, which meant that temperatures for any part of the world could be faithfully recreated.
The 36 separate major components were made in the Vickers-Armstrongs shipyard at Barrow-in-Furness in Cumbria before being transported to Brooklands for assembly. In a major engineering exercise which lasted approximately a year from the autumn of 1946 until September 1947, a large workforce from the Barrow shipyard, comprising shipwrights, welders, fitters, platers and carpenters, assembled the Chamber in a position north of where it now stands. The 200 ton (181 tonne) Chamber was then ‘launched’ like a ship down an 80 yard (73 metre) long timber ‘slipway’, taking 21 minutes for the completed Chamber to reach its foundations.
How it was used
Amongst the many tests carried out were altitude and climate tests on aircraft structural specimens such as the Vickers Viscount, VC10, Vanguard, de Havilland Sea Vixen and helicopters such as the Westland Wessex.
Other research and experimental establishments also made use of the Chamber’s capabilities, notably proof testing items such as naval guns, clear-vision windows, torpedo launchers, armoured vehicles, and airfield and marine radar.
Some surprising uses were made of the Chamber including the development of clothing for Antarctic exploration and testing buses for use at 15,000 feet in the Andes. Some explorers even tested themselves in the freezing and rarefied conditions they were likely to encounter.
An important test was carried out on fishing trawlers following the mysterious loss of two vessels in Arctic waters in the 1950s. A 1/12 scale model trawler was floated in the Chamber in simulated gale and freezing conditions. The build-up of ice on the rigging and its effect on the boat’s stability was then observed and measured until the trawler capsized.