The Bristol Type 175 Britannia is a retired British medium-to-long-range airliner built by the Bristol Aeroplane Company in 1952 to meet British civilian aviation needs. During development two prototypes were lost and the turboprop engines proved susceptible to inlet icing, which delayed entry into service until remedied.
By the time development was complete, "pure" jet airliners from France, the United Kingdom, and the United States were about to enter service, and only 85 Britannias were built before production ended in 1960. The Britannia is considered one of the landmarks in turboprop-powered airliner design and was popular with passengers. It became known as "The Whispering Giant" for its quiet exterior noise and smooth flying, although the passenger interior remained less tranquil.Littlefield 1992, pp. Cover, preface."Bristol Britannia 312." RAF Museum Cosford. Retrieved: 19 October 2010.
Canadair purchased a licence to build the Britannia in Canada, adding another 72 aircraft in two variants. These were the stretched Canadair CL-44/Canadair CC-106 Yukon, and the greatly modified Canadair CP-107 Argus maritime patrol aircraft.
Design and development Origins In 1942, during the Second World War, Allied aircraft construction saw the British, of necessity, concentrating on heavy bombers, leaving the production of transport aircraft to the USA.Hayward 1989, pp. 38–39. This would have left Britain with little experience in transport construction at the end of the war. In 1943, a committee under Lord Brabazon of Tara investigated the future British civilian airliner market. The Brabazon Committee called for several aircraft to be developed to its specifications for Britain's civilian aviation needs.Hayward 1989, p. 40.
Bristol won the Type I and Type III contracts, delivering their Type I design, the Bristol Brabazon in 1949.Woodley 2003, p. 9. The requirement for the 1946 British Overseas Airways Corporation (BOAC) Medium Range Empire (MRE) Requirements coincided with the Type III, Specification C.2/47, issued in April 1947 by the Minister of Supply.Oughton 1973, p. 96. The specifications called for an airliner capable of carrying 48 passengers and powered with Bristol Centaurus radial engines or Napier Nomad turbo-compound Diesel engine.Swanborough 1962, p. 26. Turboprop options were also considered, but they were so new that Bristol could not guarantee their performance.Oughton 1973, p. 97.
Although company Proposals "X" for conversions of Lockheed Constellations to Centaurus 662 powerplants or "Y" for licence production of the Constellation were considered in late 1946, BOAC decided that a new design was preferred. After wrangling, the Ministry of Supply and BOAC agreed costs and the project went ahead being assigned the company designation Model 175 in July 1948.Barnes 1964, p. 344. Three prototypes were ordered with the first being Mk 1 (Centaurus 662) and the second and third prototypes called Mk 2 (to be convertible to Bristol Proteus turboprops, then under development).
In October 1947, with work underway, Bristol had settled on a Centaurus-powered design with a gross weight of and a payload of . The anticipated Karachi–Cairo run necessitated a 48-seat limit including sufficient fuel for the lengthy stage. On 5 July 1949, the Ministry of Supply ordered five prototypes with the understanding that BOAC would contract for 25 production aircraft. BOAC purchased options for 25 aircraft on 28 July powered by the Bristol Centaurus, but to be re-fitted with the Bristol Proteus when available.
Redefinition and prototypes In November 1948, the Type 175 was revised again to accommodate 74 passengers and a longer wingspan in a contemplated long-range version aimed at long-haul Empire and transatlantic routes, rather than the medium-haul Empire routes originally planned.Taylor 1982, pp. 33–34. On reflection, BOAC decided that only the Proteus engine was viable, necessitating a further redesign eliminating the Centaurus option. Senior figures within BOAC such as the Deputy Chairman Whitney Straight considered the Proteus engine to be "an obsolete contraption".Gunn 1988, p. 22. Despite BOAC's desire to have a turboprop engine, the Type 175 project was contingent on the Proteus passing a 150-hour type test.Carvell 2005, p. 70.
During April 1950, the airliner's name, Britannia, was selected. The name Britannia 101 was applied to first pair of prototypes, which were powered by the early Proteus 625, the successor to the 600 series engine that had already completed type trials.Carvell 2005, pp. 68, 70. The first prototype, registered G-ALBO, with Bristol Chief Test Pilot A.J. "Bill" Pegg at the controls, first flew on 16 August 1952 at Filton Aerodrome.Carvell 2005, p. 67. During the maiden flight, the over-sensitive flying controls led to wild pitching before Pegg restored control. During the landing approach, smoke filled the cockpit and the main undercarriage bogie temporarily stuck, only fully deploying seconds before landing. The snags were resolved and by September, the prototype was cleared to perform at the 1952 SBAC Display at Farnborough where spectators commented on the "quietness" of the giant airliner.Carvell 2005, p. 68. In November 1952, Popular Science reported that by 1954 BOAC would have 25 of these aircraft on routes such as London-to-Tokyo over the Arctic and North Pole."Turboprop to Speed Pole-Hopping Tourists." Popular Science, 161(5), November 1952, p. 73.
Delays After three de Havilland Comets crashed without explanation in 1953 and 1954, the Air Ministry demanded that the Britannia undergo lengthy tests."Giant Bathtub Puts the Pressure on Turbo-Prop Airliner." Popular Science, 167(4), October 1955, p. 112. Further delays were attributed to teething problems with the engine resulting in the loss in February 1954 of the second prototype, G-ALRX, caused by a failed reduction gear that led to an engine fire and the aircraft landing on the mudflats of the Severn Estuary. Finally, time was lost in resolving inlet icing issues (by selecting a different cruising height) that were discovered as the first aircraft were being delivered to BOAC. These were exaggerated by BOAC, devastated future sales and delayed the Britannia's introduction by two years.Gunston 2006, p. 37.Gunn 1988, p. X."A Solution for the Britannia." The New Scientist,, 2(50), 31 October 1957, p. 5.
The first prototype G-ALBO was modified to more closely approximate a production standard, but was retained by the company to undergo engine testing and development.Carvell 2005, p. 71. Bristol revised the design into a larger transatlantic airliner for BOAC, resulting in the Series 200 and 300; the Britannia 300LR (Long-Range) was viewed as being "eminently suitable" for BOAC's services between London and Sydney.Gunn 1988, p. 43. The purchase price for each Britannia 100-series aircraft was agreed by BOAC in 1955 at £768,000."Britannia 100." Flight, 18 November 1960.
Australian airline Qantas considered the procurement of a Britannia fleet, however its protracted development eroded any competitive advantage against the Douglas DC-8 and de Havilland Comet 4.Gunn 1988, pp. 39–39. Route-proving trials continued through 1955, although orders were on the books from El Al and Canadian Pacific Air Lines alongside the standing order placed by BOAC.
During the first eight months of its operational trials, a total of 16 in-flight engine failures and 49 unscheduled engine changes punctuated the ongoing engine problem and delayed the Britannia's in-service date until February 1957, roughly two years late.Orlebar 2002, p. 27.Carvell 2005, p. 74. The Britannia received a fair amount of attention in both the popular press and the British House of Commons, especially when it was revealed that BOAC had contemplated fitting Rolls-Royce Tynes to their fleet of Douglas DC-7s as an interim measure until the Britannia was cleared for service.
In 1956, Bristol's managing director Peter Masefield flew the tenth production Britannia, G-ANBJ, on a world sales tour. American interest was strong, since the Britannia seemed to be a faster, longer-range, higher-capacity sister of the Vickers Viscount, which was already a marketing success on US domestic routes, and, compared to the piston-engined DC-7C, itself a new type, the Britannia offered similar transcontinental or transatlantic range with greater speeds and the public appeal of more modern powerplants. Eastern Air Lines and TWA both wished to place orders, which might have forced competitors to follow suit. TWA's majority owner Howard Hughes took the controls of the Britannia for one flight and immediately requested 30 aircraft. However, the Americans wanted delivery within a couple of years, and Bristol, with its limited production facilities and the prior commitment to the BOAC order, could not meet that requirement, so, with the Boeing 707 and Douglas DC-8 jets expected in service by 1958–9, the opportunity passed.Hamilton-Paterson 2010, p.268.
Aviation historian Peter Pigott summarised the impact of the delays:
Related developments
In 1954, a licence was issued to Canadair to build the derivative Canadair CL-28/CP-107 Argus, and the Canadair CL-44/Canadair CC-106 Yukon. Based on the Britannia, the Argus maritime patrol and anti-submarine military aircraft was optimised for endurance on long-range patrol, not speed, and used four Wright R-3350-32W Turbo-Compound engines that used less fuel at low altitude.Piggot 2005, p. 168. Unlike its Britannia forebear, the Argus was a hybrid, using the Britannia wings, tail surfaces and landing gear matched to a "purpose-built", unpressurised fuselage. It substituted North American materials and standard parts for British parts.Pickler and Milberry 1995, pp. 145–155.
The interior of the Argus was well equipped to conduct anti-submarine warfare — navigation, communication and tactical electronic equipment along with weapon loads that included bombs, torpedoes, mines and depth charges. A total of 33 Argus aircraft were built in two series (Mk 1 and Mk 2), serving the Royal Canadian Air Force (RCAF) and Canadian Forces from 1957 to 1982.
Canadair built 39 Canadair CL-44/Canadair CC-106 Yukon turboprop Rolls-Royce Tyne-powered aircraft, comprising 12 CC-106 Yukon for the RCAF and 27 CL-44D4 passenger/cargo variants for the civil market. Civilian operators typically operated the type as freighters. Four CL-44D4s were converted as CL-44Js with lengthened fuselages for service with the Icelandic "budget" airline Loftleiðir. The CL-44D4s were all built with swing-tails to allow straight-in cargo loading and served with a variety of carriers, most notably Flying Tiger Line.Pickler and Milberry 1995, pp. 148–149.Woodley 2003, p. 130. The similar CC-106 Yukon was used by the RCAF in a solely passenger configuration.Piggot 2005, p. 146.
A final "one-off" development was the Conroy Skymonster, nicknamed Guppy, based on a Canadair CL-44D4 N447T. The prominent modification was an enlarged fuselage, like the Mini Guppy, which was produced by Jack Conroy's previous company, Aero Spacelines.Savage, Daren. "Conroy Aircraft CL-44-O Skymonster (Guppy CL44)." All About Guppys, 2008. Retrieved: 20 October 2010. After a long operational career as a freighter, the Guppy was stored at Bournemouth Airport in 2003 and was later sold."Cl-44 Association." swingtail44.blogspot.com. Retrieved: 20 October 2010.
Operational history