Imperial Airship Scheme
The British Imperial Airship Scheme was a 1920s project to improve communication with the far corners of the British Empire by establishing air routes using airships. This led to the construction of two large and technically advanced airships of similar design, the R100 and the R101. The scheme was terminated in 1931 following the crash of R101 while attempting its first flight to India.
In 1922 Vickers proposed a scheme for the development of large commercial airships to provide a passenger service to link the countries of the British Empire. Named the Burney scheme after its creator Dennistoun Burney, it involved the construction of six airships at an estimated cost of £4 million to be constructed and operated by Vickers . The use of heavier-than-air craft over such distances was seen as impractical at this time, while an airship service across the Atlantic was already in operation.
Following the coming to power of Ramsay MacDonald's Labour adminitration in 1924, the Burney Scheme was rejected and replaced by the Imperial Airship Scheme. This entailed the construction of two airships: one, R100, to be designed and built by a specially established Vickers subsidiary, the Airship Guarantee Company managed by Burney, and the other designed by the Government's Royal Airship Works at Cardington. The R100 would largely use existing technology, while the R101 was intended to act as an experimental test-bed for innovatory and techniques in airship design. The two ships were soon labelled the "Capitalist" ship (R100) and the "Socialist" ship (R101). Further airships would include the best features from both.
Both airships were designed to the same technical specification. This demanded airships with passenger accommodation for 100, a fuel capacity adequate for 57 hours flight at a cruising speed of 63 mph (101 km/h). Acceptance of the airships was conditional upon the completion of a flight testing program which culminated in a flight to India, with a stop in Egypt for refuelling. A further requirement was that both had to conform to an as-yet unformulated formula for airframe strength.
The R100 was designed by Barnes Wallis, with Nevil Shute Norway as Chief Calculator, responsible for all the stress calculations. Writing under the name of Nevil Shute, Norway later became a successful novelist, and also wrote a memoir, Slide Rule: Autobiography of an Engineer which gives an account of the airship development program. Design of the R101 was under the direction of Lt.Col. V. C. Richmond. with Michael Rope as his assistant and Harold Roxbee Cox as chief calculator.
It was considered that petrol was unsuitable as a fuel for airships intended for use in hot climates due to its low flash point. For this reason R101 was powered by diesel engines, and R100 was originally intended to use engines using a mixture of hydrogen and kerosene . The program to develop the diesel engines was beset with difficulties, the engines being both overweight and unable to produce the expected power output. Similarly the development of hydrogen/kerosene engines ran into difficulties and so the R100 team made a decision to use existing petrol-fuelled aircraft engines. This resulted in Canada being substituted for India as the destination of the acceptance trial flight.
The initial timetable, drawn up in March 1924, expected construction of R.101 to begin in July 1925 and be complete by the following July, with a trial flight to India being planned for January 1927. R100 was also delayed, and neither flew until late 1929. The delay to the R.101 was largely due to the extensive research program which preceded its construction: among other things this involved the construction and load-lting of an entire bay of the proposed design. The delay to R100 was the result of the limited resources available, a result of it being constructed under a fixed-price contract: It was obvious fairly early in the design procss that design and construction costs would exceed the purchase price.
Both airships were overweight, R101 more so than R100, partly due to its diesel engines. These were both heavier than expected and also did not have the anticipated power output. R.101's weight problem was compounded by its having a smaller gas capacity than R100, a result of its innovatory structural design, in which the transverse ring-frames occupied a larger proportion of the interior volume of the ship.
|R101||R101 after extension||R100|
|Total fixed weight||113.60 long tons (115.42 t)||117.90 long tons (119.79 t)||105.52 long tons (107.21 t)|
|Engines weight||12.63 long tons (12.83 t)||12.26 long tons (12.46 t)||6.22 long tons (6.32 t)|
|18 long tons (18 t)||18 long tons (18 t)||18 long tons (18 t)|
|Gasbag capacity||4,893,740 cu ft (138,575 m3)||5,509,753 cu ft (156,018.8 m3)||5,156,000 cu ft (146,000 m3)|
Gasbags at 96% capacity
pressure height of 1,200 ft (370 m)
|142.62 long tons (144.91 t)||160.57 long tons (163.15 t)||150.26 long tons (152.67 t)|
In August 1930, R100 made the transatlantic journey to North America, visiting Quebec, Montreal and Toronto.
R101 was dispatched on a flight to India under marginal conditions in October 1930, with a hastily issued Certificate of Airworthiness. She crashed soon after leaving on a stormy night in France. The R101 had had an extra gas cell inserted in the middle to give adequate lift for the trip to India, and this trip was to be the first full-load test with the additional section. The exact cause is still a matter of dispute amongst airship enthusiasts and historians. Sir Peter Masefield lists thirteen factors in his detailed history of R101: without any one of them the disaster might not have happened. The desire of all involved to achieve a flight to India before the conclusion of the 1930 Imperial Conference (at which decisions would be taken on the future of the airship programme) led to a premature flight in adverse weather conditions.
Proposals in 1930 (initially called Project H) were for scheduled airship services from 1931 from Cardington to Karachi and Montreal with R100 and R101 (both lengthened with additional bays) until 1934 when additional and larger airships, the R102 (an enlarged R101 with 8,300,000 cubic feet (240,000 m3) capacity) and the R103 (of around 9,500,000 cubic feet (270,000 m3) capacity) would be available. By 1935 the four airships would offer monthly return services to Montreal and Karachi and a weekly service to Ismailia in Egypt. A service to Australia was to start in 1936, and an even larger airship, the R104 was proposed.
But on 31 August 1931 the Cabinet decided to abandon British airship development, although Cardington would still keep a watching brief on overseas developments. The R100 was broken up. Proposals for the planned R102, R103 and R104 airships were now all abandoned. The loss of R101, the deepening world depression, and doubts about the optimistic financial forecasts, were all factors in these decisions.
Air routes to the Empire were instead pioneered by Imperial Airways starting in 1929, initially using flying boats and later landplanes.
- The Airship SchemeFlight 6 April 1922
- Shute, Nevil, Slide Rule. London: William Heinemann, 1954 page 56: "It was generally agreed in 1924 that the aeroplane would never be a very suitable vehicle for carrying passengers across the oceans, and that airships would operate all the long-distance routes of the future. We were all quite wrong, of course, but at that time it seemed reasonable; no aeroplane had yet succeeded in crossing the Atlantic from east to west, whereas a German airship, the Graf Zeppelin, was already carrying commercial loads of passengers both ways to South America upon a regular schedule.
- Masfield 1982, pp 454-7
- Masefield 1982 p. 51
- Masefield 1983 pp. 476-7
- Masefield pp 431-437 (1982, William Kimber, London) ISBN 0-7183-0068-8
- 'Masefield 1983 pp. 526-539
- Masefield, P. To Ride the Storm: The Story of the Airship R.101 London: Kimber, 1982. ISBN 0 7183 0068 8