|HM Airship R100|
|R100 at its mooring mast in St. Hubert, Quebec, Canada.|
|National origin||United Kingdom|
|First flight||16 December 1929|
His Majesty's Airship R100, known simply as the R100, was a privately designed and built rigid British airship made as part of a two-ship competition to develop a commercial airship service for use on British Empire routes as part of the Imperial Airship Scheme. The other airship, the R101, was built by the British Air Ministry, but both airships were funded by the Government.
The R100 was built by the Airship Guarantee Company, a specially-created subsidiary of the armaments firm, Vickers-Armstrongs, led by Commander Dennis Burney, with the design team headed by Barnes Wallis, later famous for his invention of the bouncing bomb. The design team also included Nevil Shute Norway as the senior stress engineer.[N 1]
The R100 first flew in November 1929. It made a series of trial flights and a successful return crossing of the Atlantic in July–August 1930, but following the crash of R101 in October 1930 the Imperial Airship Scheme was terminated and it was broken up for scrap.
The R100 was built as part of a British government programme to develop airships to provide passenger and mail transport between Britain and the countries of the British Empire, including India, Australia and Canada. This had its origin in Dennistoun Burney's 1922 proposal for a civil airship development programme to be subsidised by the Government and carried out by a specially established subsidiary of Vickers. When the General Election of 1923 brought Ramsay MacDonald’s Labour administration to power, the new Air Minister, Lord Thomson formulated the Imperial Airship Scheme in its place. This called for the building of two experimental airships: one, R101, to be designed and constructed under the direction of the Air Ministry, and the other, R100, to be built by the Vickers' subsidiary under a fixed price contract.
Design and development
The R100 was constructed at the former RNAS Air Station Howden in Yorkshire, a remote location 3 mi (4.8 km) from Howden and 25 mi (40 km) from Hull. Design work began in 1925 while at the same time the somewhat rundown site was put in order and a hydrogen-generating plant installed.
The specially established subsidiary of Vickers, the Airship Guarantee Company, faced substantial difficulties. The contract for R100's construction was a fixed price one and it was obvious from very early on that the project would incur a loss, and so economies were made; for instance, only a dozen machine tools were in use for construction of the airship. There were also difficulties in finding skilled workers due to the remoteness of the location, and a large proportion of the workers were local people who had to be trained. Conditions in the unheated airship shed were also poor: the roof leaked, ice formed on the girders in winter, and condensation caused corrosion of the airship's duralumin structure, so that the girders had to be varnished. For three years the actual assembly work was close behind that of the designers, and the progress of the design work was the determining factor in speed of construction.
Both R100 and R101 used a smaller number of longitudinal girders than previous airships in order to simplify stress calculations. Even so, the calculations for the transverse frames required hand computation that took two or three months to produce a solution for each frame. The thoroughness of the stressing calculations was a consequence of new Air Ministry criteria for the strengths required of airships, formulated in response to the catastrophic structural failure of R38 in 1921. However, fewer longitudinal girders resulted in larger unsupported panels of fabric in the envelope. Flight trials were to prove that the R100's covering was barely adequate. The envelope of R101 was also unsatisfactory, and a failure in its cover was possibly a cause of its crash.
Barnes Wallis created the frame of the airship using only 11 standardized components. The 16 longitudinal girders were formed of three tubes each, formed from strips of Duralumin wound into a spiral and riveted together. These connected 15 polygonal transverse frames, which were held in shape by wire bracing connected to a central longitudinal girder running the length of the ship. A further consequence of the new rules for airframe stress design was that a new way of harnessing the lifting force of the gasbags had to be found. Wallis's solution to this problem later led to his innovative geodesic airframe fuselage and wing design for the Wellesley, Wellington and Windsor bombers.
The elevators were aerodynamically balanced but the rudders were unbalanced. When the designers learned that R101 had been fitted with servo motors at a substantial cost in weight and money they thought that they had made a mistake and rechecked their calculations. They eventually concluded that their calculations had been correct: when R100 was flown the controls proved both light and effective, and its control characteristics were compared favorably with those of R101 by Nöel Atherstone, First Officer of the R101.
The R100 was built suspended from the roof of its shed. The individual transverse frames were assembled horizontally then lifted up and slung from roof-mounted trackways before being slid into position and attached to the adjacent frames by the longitudinal girders. The ship remained suspended until the gasbags were inflated with hydrogen.
By summer 1929 the ship's structure was nearly complete and her gasbags were inflated. Following inflation of the gasbags, the outer covering of linen fabric painted with aluminum aircraft dope was put in place, and she was completed at the beginning of November. Lift and trim trials were carried out on 11 November: empty weight was 105.52 long tons (107.21 t) and gasbag volume was 5,156,000 cu ft (146,000 m3), giving a standard gross lift of 156.52 long tons (159.03 t) and so a disposable lift of 51.00 long tons (51.82 t). Deducting 18 long tons (18 t) for the service load (crew, stores and ballast) this meant the weight available for fuel and payload was 33.00 long tons (33.53 t).
It had originally been intended to design special engines for R100 which would be fuelled by hydrogen and kerosene but after a years' work it was realized that the engine would not be developed in time and it was decided to fit the Beardmore Tornado diesel engine that was being developed for the Air Ministry for installation in R101. However at a very early stage the Tornado was judged unsuitable due to its weight and other problems. Wallis finally settled on the use of six reconditioned Rolls-Royce Condor petrol engines even though the fuel, with its lower flash point, was considered to be a fire risk under tropical conditions. The engines were contained in three gondolas, each with one engine driving a 17 ft (5.18 m) diameter tractor propeller and a second driving a 15 ft (4.57 m) diameter pusher propeller. The engines driving the pusher propellers were also fitted with a gearbox to provide reverse thrust for docking the airship.
Passenger and crew accommodation
The passenger and crew accommodation were arranged on three decks occupying a single bay of the structure and entirely contained within the airship's envelope. The lower deck contained the crew accommodation. The second deck had a dining room, which doubled as the passenger lounge, plus the kitchen, 18 four-berth passenger cabins and a gallery on either side for passengers to enjoy the view through the windows built into the skin. The third deck consisted of a gallery running around the dining-room and 14 two-berth cabins.
R100 made her maiden flight in the morning of 16 December 1929. After departing Howden at 07.53, she flew slowly to York then set course for the Government Airship Establishment at Cardington, Bedfordshire, running on five engines since one of the engines had to be shut down due to a cracked water jacket, and completing the mooring process at 13.40. A second flight was made the next day, with the intention of making a flight to London, but shortly after slipping the mast a strip of fabric became detatched from the lower fin, and the flight was limited to a cruise around Bedfordshire to test control response, lasting 6hr 29 min. The following day R100 was taken from the mast to No.2 shed at Cardington and work on modifying the wiring holding the cover in place begun: this took until 11 January 1930.
During a test on 16 January 1930, R100 achieved a speed of 80.5 mph (129.6 km/h). At speed a problem with the outer covering became apparent: it tended to ripple and flap excessively in the form of a standing wave. Cine films were taken of this phenomenon which occurred due to the large areas of unsupported fabric; it is also clearly visible in some photographs.
Transatlantic Voyage to Canada
The R100's contract originally called for a final acceptance trial flight of 48 hours duration and a demonstration flight to India. The decision to use petrol engines resulted in a change in destination to Canada, as it was considered that a flight to the tropics with petrol aboard would be too hazardous.
Following a final acceptance trial of 54 hours, R100 was formally handed over to the Air Ministry, and a number of modifications were made in preparation for her transatlantic flight. During her last flight the tail fairing had collapsed due to aerodynamic pressures and her pointed tail was modified to a more rounded form, shortening her length by 15 ft (4.6 m).
Shortly before the R101's flights in June 1930, the Cardington engineers tentatively suggested that the long flights to Canada and India might be postponed until 1931 on the grounds that neither of the two airships was fit to make a lengthy flight at their current developmental stage. The R100 team replied that their airship was perfectly capable of flying to Canada, and furthermore the Canadian flight was a part of their contract.
The R100 duly departed for Canada on 29 July 1930, reaching its mooring mast at the St-Hubert, Quebec Airport (outside of Montreal) in 78 hours, having covered the great circle route of 3,300 mi (5,300 km) at an average ground speed of 42 mph (68 km/h). The airship stayed at Montreal for 12 days with over 100,000 people visiting the airship each day while she was moored there, and a song was composed by La Bolduc to commemorate, or rather to make fun of, the people's fascination with the R100. She also made a 24-hour passenger-carrying flight to Ottawa, Toronto, and Niagara Falls while in Canada. The airship departed on her return flight on 13 August, reaching Cardington after a 57½ hour flight.
Nevil Shute later suggested in Slide Rule: Autobiography of an Engineer that the success of the R100's Canadian flight indirectly led to the R101 disaster. Prior to the transatlantic flight, the Cardington team could suggest that neither airship was ready for a performance of such duration. However when the R100 returned in triumph they had to either make the flight to India or admit defeat - which would have meant discredit with the consequent danger of losing their jobs.
The end of the British airships
The tale of the design of R100 and its claimed superiority to R101 is told in Shute's Slide Rule: Autobiography of an Engineer, first published in 1954. Although flawed and not quite as overwhelmingly superior as Nevil Shute implied, the R100 represented the best that conventional airship technology in Britain had to offer at the time. The R101 suffered in comparison partly because of her many groundbreaking but ultimately problematic innovations, and also because of the weight of her diesel engines. In terms of lifting efficiency, both were inferior to the smaller LZ 127 Graf Zeppelin.
After the R101 crashed and burned in France, en route to India on 5 October 1930, the Air Ministry ordered R100 grounded. She was deflated and hung up in her shed at Cardington for a year whilst three options were considered: a complete refit of R100 and continuation of tests for the eventual construction of R102; static testing of R100 and retention of about 300 staff to keep the programme "ticking over"; or retention of staff and the scrapping of the airship. In November 1931, it was decided to sell R100 for scrap. The entire framework of the ship was flattened by steamrollers and sold for less than £600.
Specifications (as first flight)
Data from 
- Crew: 37
- Capacity: 100
- Length: 719 ft 9.5 in (219.393 m)
- Diameter: 133 ft 4 in (40.64 m)
- Volume: 5,156,000 cu ft (146,000 m3)
- Empty weight: 236,365 lb (107,213 kg)
- Useful lift: 350,607 lb (159,033 kg)
- Powerplant: 6 × Rolls-Royce Condor IIIB 12 cylinder, 650 hp (480 kW) each
- Maximum speed: 81.5 mph (131 km/h; 71 kn) 
- Range: 4,095 mi (3,558 nmi; 6,590 km) with 3 tons payload
- Aircraft of comparable role, configuration and era
- Norway later became famous as a novelist, writing under the name of Nevil Shute
- Masefield 1982 p.165
- Masefield p. 189
- Ventry and Kolesnik 1977, p. 137.
- Masefield 1982 pp.168-9
- Hartcup 1974, p. 189.
- Masefield 1982 p.166
- Masefield 1982 pp.171-2
- Masefield 1983, pp.172-3.
- Masefield 1982 p.206
- "R100 Meets End". Popular Aviation: 225. October 1932.
- Masefield 1983, pp.168-9.
- Masefield 1983, p.495.
- Gilbert, James. The World's Worst Aircraft. Walton-on-Thames, England: Michael Joseph, Third Edition 1975. ISBN 978-0-7181-1269-1.
- Griehl, Manfred and Joachim Dressel. Zeppelin! The German Airship Story London: Arms & Armour, 1991. ISBN 1-85409-045-3.
- Hartcup, Guy. The Achievement of the Airship: A History of the Development of Rigid, Semi-rigid, and Non-rigid Airships. London: David & Charles, 1974. ISBN 978-0-85885-193-1.
- Higham, Robin. The British Rigid Airship, 1908-1931 London: Foulis, 1961.
- Masefield, P. To Ride The Storm. London: William Kimber, 1982. ISBN 0 7183 0068 8
- Morpurgo, J.E. Barnes Wallis: A Biography. London: Longman, 1972. ISBN 0-582-10360-6.
- Mowthorpe, Ces. Battlebags: British Airships of the First World War: An Illustrated History. London: Alan Sutton Publishing, Ltd., 1995. ISBN 0-905778-13-8.
- Shute, Nevil. Slide Rule: Autobiography of an Engineer. London: William Heinemann, 1954. ISBN 1-84232-291-5.
- Ventry, Lord and Eugene Kolesnik. Airship Development (Jane's Pocket Book 7). Durham, UK: Macdonald Press, 1976. ISBN 0-356-04656-7.
- Ventry, Lord and Eugene Kolesnik. Airship Saga: The History of Airships Seen Through the Eyes of the Men who Designed, Built, and Flew Them. Poole, Dorset, UK: Blandford Press, 1982. ISBN 0-7137-1001-2.
- Ward, Ian and Brian Innes, eds. The World of Automobiles: An Illustrated Encyclopedia of the Motor Car. London: Orbis, 1974.
|Wikimedia Commons has media related to: R-100|
- The R100 in Canada (pdf)
- Airship heritage Trust R100
- Flight magazine feature on the R100 from 1929 (pdf)