Avro Tudor
| Company type | Aircraft model |
|---|---|
| Industry | Aviation, Aerospace |
| Predecessor | Avro Lincoln |
| Founded | 1943 |
| Founder | Roy Chadwick (designer) |
| Headquarters | Manchester , United Kingdom |
| Products | Piston-powered airliner (Type 688 Tudor) |
The Avro Type 688 Tudor represented a British piston-powered airliner derived from Avro's four-engine Lincoln bomber, which itself evolved from the renowned Lancaster heavy bomber. It holds the distinction of being the first pressurised airliner developed in Britain. However, the aircraft was largely perceived by buyers as merely a pressurised version of the Douglas DC-4, resulting in limited sales as key operators favoured American models. Additionally, its conventional tailwheel undercarriage was considered outdated and a competitive drawback.
Development
In response to Specification 29/43, Avro initiated development of the Type 688 Tudor in 1943. This specification called for a commercial adaptation of the Lancaster IV bomber, later renamed the Lincoln. The requirements stemmed from the Brabazon Committee, which had outlined specifications for nine categories of postwar civil aircraft.
Initially, Avro proposed the Avro 687 (also known as Avro XX), which was essentially a Lincoln bomber featuring a new circular-section pressurised fuselage and a single large vertical stabiliser replacing the previous twin fins and rudders. However, during design development, the concept shifted away from a straightforward conversion to a new design—the Avro 688—which retained the four Rolls-Royce Merlin engines. Designed by Roy Chadwick, wartime constraints meant he could not create an entirely new aircraft but had to utilise existing components, tooling, and jigs. Building on the Lincoln’s wing structure, Chadwick developed a Tudor with a circular cross-section pressurised fuselage capable of carrying a useful load of approximately 3,765 lb (1,705 kg) and offering a range near 3,975 mi (6,400 km).
Two prototype units were commissioned in September 1944. The first prototype, registered G-AGPF, was assembled by Avro’s experimental flight division at Manchester’s Ringway Airport and completed its maiden flight on 14 June 1945. This marked it as Britain’s first pressurised civilian aircraft, although initial test flights were conducted without pressurisation. The Tudor I prototype was equipped with Rolls-Royce Merlin 102 engines producing 1,750 hp (1,305 kW), while production models typically used the more powerful Merlin 621 engines rated at 1,770 hp (1,320 kW).
Design
The Tudor featured a low-wing cantilever monoplane design powered by four engines, equipped with a single vertical fin and rudder, and originally incorporated a retractable tailwheel landing gear.
Its wing utilized a NACA 23018 airfoil at the root and was constructed as a five-section, all-metal, twin-spar assembly. The untapered central section supported the inboard engines along with the primary landing gear, while the inner and outer wing panels tapered at both the leading and trailing edges. The outboard engines were mounted on the inner sections. The ailerons included both trim and balance tabs, and hydraulically actuated split flaps were arranged in three segments along each side of the trailing edges of the center and inner wing sections. Fuel was stored in eight bag tanks—one on each side of the fuselage within the center section and three tanks located in each inner wing—providing a total capacity of 3,300 imp gal (15,000 L; 4,000 US gal).
The tail assembly was entirely metal, featuring a dorsal fin seamlessly integrated with the fuselage, and a 43 ft (13 m) twin-spar tailplane equipped with inset, divided elevators. All control surfaces were mass-balanced and included adjustable trim tabs as well as servo tabs for enhanced control.
The fuselage had a circular cross-section and was built as an all-metal semi-monocoque structure measuring 10 ft (3.0 m) in diameter. To improve cabin comfort, kapok insulation was installed above floor level. The main landing gear units were hydraulically operated, similar to those used on the Lancaster, featuring single Dunlop wheels that retracted rearwards into the nacelles of the inboard engines. The twin tailwheels also retracted rearwards into the fuselage and were covered by dual longitudinal doors.
Tudor I
Designed primarily for transatlantic service, the Tudor I faced stiff competition from American aircraft such as the Douglas DC-4 and Lockheed Constellation, both of which offered greater passenger capacity than the Tudor’s 12 seats and weighed less than its approximately 70,000 lb (32,000 kg). Additionally, its tailwheel undercarriage configuration was considered outdated. Nevertheless, the Ministry of Supply placed an initial order for 14 Tudor I planes on behalf of BOAC, later increasing this to 20 units in April 1945.
The Tudor I encountered several stability challenges, including issues with both longitudinal and directional control. These problems were investigated by the Royal Aircraft Establishment at RAE Farnborough, where extensive testing took place under test pilot Eric Brown. Following their advice, modifications were made such as installing a larger tailplane and replacing the original fin and rudder with bigger vertical surfaces. However, BOAC contributed to further delays by demanding over 340 changes before ultimately rejecting the Tudor I on 11 April 1947, deeming it unsuitable for North Atlantic service. Plans to produce 12 Tudors in Australia for military transport purposes were eventually scrapped.
Out of twelve Tudor I aircraft constructed, three were dismantled while others underwent conversion into Tudor IVB or Tudor Freighter I variants.
Due to these setbacks with the Tudor I, BOAC—backed by the Ministry of Civil Aviation—requested approval to acquire aircraft with proven operational records such as the Lockheed Constellation and Boeing Stratocruiser for its Atlantic routes instead. Despite BOAC’s hesitation towards adopting Tudors, financial support from the Ministry of Supply for the program persisted.
Tudor II
The Avro 688's limited seating capacity prompted the immediate development of a larger model. Known as the Avro 689 or Tudor II, this variant was designed to accommodate 60 passengers for BOAC. Its fuselage was extended to 105 ft 7 in (32.18 m), a significant increase from the Tudor I’s length of 79 ft 6 in (24.23 m), and its diameter was enlarged by 1 ft (0.30 m) to 11 ft (3.4 m), making it the largest British airliner of its era.
By late 1944, even before the design was finalized, BOAC, Qantas, and South African Airways agreed to standardize on the Tudor II for routes within the Commonwealth. As a result, BOAC raised its initial order from 30 to 79 aircraft.
The prototype Tudor II, registered G-AGSU, took to the skies for the first time on 10 March 1946 at Woodford Aerodrome. However, design modifications led to diminished performance, rendering the aircraft unsuitable for operations in hot and high-altitude environments. Consequently, Qantas opted for the Constellation, and South African Airways chose the Douglas DC-4, reducing total orders to 50.
Tragically, on 23 August 1947, the prototype crashed during takeoff at Woodford, resulting in the death of designer Roy Chadwick. Investigations revealed that improper assembly of the aileron control system caused the accident.
The second prototype was re-engined with Bristol Hercules radial engines and designated as the Tudor 7, though it never entered production. After unsatisfactory tropical trials, BOAC declined to operate the Tudor II; only three production examples were completed. Meanwhile, six aircraft were constructed for British South American Airways (BSAA) under the name Tudor V.
The third pre-production Tudor II, initially registered G-AGRZ, was utilized for pressurization testing at RAE Farnborough under military serial VZ366.
The second completed Tudor II, G-AGRY, underwent tropical testing in Nairobi as VX202, but due to poor results, orders were further cut to 18 units. Ultimately, only four Tudor IIs were finished including the prototype.
Starting in 1946, concerns arose over British government policy as operators like BOAC considered purchasing American aircraft. Critics argued that failing to support the Tudor damaged the UK’s civil aviation industry. L.G.S. Payne of The Daily Telegraph criticized Ministry of Supply planners for producing aircraft that lacked competitiveness in cost, performance, and efficiency. He advocated focusing on jet-powered designs instead of interim models like the Tudor.
BOAC cancelled its Tudor orders in 1947 and instead procured 22 Canadair North Stars—renamed C-4 Argonauts—which served extensively from 1949 through 1960.
Six Tudor IIs had been slated for conversion into freighters with tricycle landing gear for BSAA under the designation 711 Trader, but these were never built. A related design incorporating similar landing gear appeared later as the jet-powered Avro Ashton.
Tudor III
Two Tudor Is—G-AIYA and G-AJKC—were sent to Armstrong Whitworth for conversion into VIP transports intended for cabinet ministers. These aircraft featured accommodations for ten passengers and nine sleeping berths. Renumbered as VP301 and VP312, both were acquired by Aviation Traders in September 1953; VP301 was subsequently reverted back to a Tudor I configuration.
In 1955, G-AIYA along with Tudor I G-AGRG were extended to meet Tudor IV specifications. Together with unmodified Tudor I G-AGRI—configured as a 42-seat airliner—they operated Air Charter Ltd’s Colonial Coach Services linking the UK with Tripoli and Lagos.
Tudor IV
To fulfill BSAA’s requirements, certain Tudor Is were stretched by 5 ft 9 in (1.75 m) and powered by Rolls-Royce Merlin engines rated at 1,770 hp (1,320 kW) and 1,760 hp (1,310 kW). These models seated 32 passengers without a flight engineer station and were designated Tudor IV; variants equipped with a flight engineer’s position and reduced seating of 28 were known as Tudor IVBs.
Opinions among BSAA pilots on these aircraft varied widely. While some praised them highly—Captain Geoffrey Womersley called it “the best civil airliner flying”—others criticized their design flaws. BSAA’s chief pilot and operations manager Gordon Store expressed dissatisfaction:
"The Tudor was constructed like a battleship but suffered from noise issues; I lacked confidence in its engines and systems. American designs were decades ahead in systems engineering. The hydraulics, air conditioning units, and recirculation fans were cramped beneath the floor without proper planning. Fuel-burning heaters failed consistently; floorboards had to be lifted repeatedly during flight."[1]
The fuel-burning heaters supplied by Janitrol were also installed on US aircraft such as the Lockheed Constellation and later on American versions of the Vickers Viscount.
The first Tudor IV example—G-AHNJ Star Panther—flew initially on 9 April 1947. It received its Certificate of Airworthiness on 18 July that year. On 29 September BSAA took delivery of G-AHNK Star Lion, beginning service flights from London Heathrow to South America via intermediate stops including Lisbon and Bermuda starting on 31 October.
On the night spanning 29–30 January 1948, Tudor IV G-AHNP Star Tiger, carrying 31 individuals, vanished without a trace between Santa Maria in the Azores and Bermuda. Following this disappearance, Tudors were grounded temporarily. Although no definitive cause was established, flights resumed on 3 December 1948 with weekly London-Buenos Aires services routed through Gander and Bermuda.
Another tragedy occurred on 17 January 1949 when Tudor IV G-AGRE Star Ariel disappeared en route from Bermuda to Kingston with twenty people aboard; this led once again to grounding of all Tudor IVs. The resulting shortage of aircraft contributed to BSAA’s absorption by BOAC. Pressurization difficulties were suspected as contributing factors in both disappearances; subsequently remaining Tudors flew unpressurized cargo missions designated Tudor Freighter IV and IVB.
A Tudor IV underwent testing at De Havilland’s Hatfield facility on April 1, 1949 for "no lift angle" evaluation before returning to Heathrow on April 8.
After years in storage at Manchester Airport, four former BSAA Tudors IV were acquired by Air Charter Limited in late 1953. Aviation Traders installed large cargo doors measuring 6 ft 10 in (2.08 m) by 5 ft 5 in (1.65 m), reclassifying them as Super Traders IV or IVB with Certificates of Airworthiness granted in March 1955. These freighters operated long-haul cargo flights reaching destinations such as Christmas Island until some remained active until a crash near Turkey involving G-AGRH Zephyr on April 23, 1959.
Tudor V
The Tudor V represented a modified stretched version of the Tudor II featuring seating for forty-four passengers. BSAA obtained five units which never entered passenger service; instead they were converted into fuel tankers supporting the Berlin Airlift. During this operation they completed a total of 2,562 sorties over nearly seven thousand hours delivering more than twenty-two thousand tons (20,071 tonnes) of fuel into Berlin.
On March 12, 1950, G-AKBY—returned to passenger use by Airflight Ltd—crashed during approach at RAF Llandow in South Wales resulting in eighty fatalities among passengers and crew.
In addition, Lome Airways leased an ex-BSAA Tudor V from Surrey Flying Services registered CF-FCY for freight duties in Canada during 1953; it was retired at Stansted and scrapped by 1959.
Tudor VI
Planned for Argentinian airline FAMA’s South Atlantic routes with configurations accommodating between thirty-two and thirty-eight seats or twenty-two sleeper berths; however none were produced.
Tudor VII
This was essentially a production version of the Tudor II fitted with Bristol Hercules radial engines aimed at improving performance. The sole example built (G-AGRX) first flew on April 17, 1946; modifications made in June 1948 included shorter landing gear and inclined engine mounts enhancing ground clearance. It served primarily for cabin temperature testing before being sold for parts in March 1954.
Tudor VIII
The second prototype of the Tudor I was rebuilt up to Tudor IV standards before being outfitted with four Rolls-Royce Nene turbojet engines mounted in paired nacelles beneath each wing. Registered as VX195, this jet-powered variant first flew from Woodford on September 6, 1948 and was showcased shortly thereafter at Farnborough’s SBAC Show. It participated subsequently in high-altitude testing at Boscombe Down and RAE Farnborough before being dismantled in 1951.
Tudor IX
Following trials with the jet-powered Tudor VIII, six units designated Tudor IX were ordered by the Ministry of Supply based on the stretched Tudor II airframe but incorporating four Rolls-Royce Nene engines along with tricycle landing gear configuration. This design evolved into what became known as the Avro Type 706 Ashton; its maiden flight occurred on September 1, 1950.
Variants
All production models were manufactured at Avro's Chadderton facility and assembled/test-flown at Woodford Aerodrome.
- 688 Tudor I
- Standard production model; twelve built initially before conversions.
- 689 Tudor II
- Lengthened variant; five constructed.
- 688 Tudor III
- Tudor I modified by Armstrong Whitworth into executive transports seating up to nine passengers; two produced.
- 688 Tudor IV
- Stretched version distinct from Tudor II (lengthened by only 6 feet ([convert: unknown unit])); accommodated up to thirty-two passengers; eleven built.
- 688 Tudor IVB
- Similar to Tudor IV but retaining flight engineer station from original Tudors; some conversions performed.
- 689 Tudor V
- Tudor II variant powered by four Rolls-Royce Merlin piston engines rated at approximately [convert: invalid number] each; six built for BSAA; one involved in fatal Llandow crash.
- 689 Tudor VI
- Ordered by Argentinian carrier FAMA but order cancelled prior to completion.
- 689 Tudor VII
- Tudor II fitted with Bristol Hercules radial engines producing about [convert: invalid number] each; single prototype.
- 688 Tudor VIII
- Tudor I converted into jet-powered variant equipped with four Rolls-Royce Nene turbojets.
- Tudor IX
- Jet-powered derivative based on stretched airframe leading to Avro Ashton development.
- Super Trader IVB
- Re-engined version featuring Rolls-Royce Merlin piston engines rated around [convert: invalid number].
- Tudor Freighter I
- Cargo adaptation used by BOAC during Berlin Airlift operations.
- 711 Trader
- Proposed freighter variant based on tricycle gear-equipped Tudor II design but never constructed.
Operators
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- Lome Airways
- Air Charter Limited
- Airflight
- British Overseas Airways Corporation (BOAC) (cargo operations only)
- British South American Airways
- Surrey Flying Services
- William Dempster (airline)
Accidents and incidents
- On August 23, 1947 – Prototype Tudor II G-AGSU crashed during takeoff from Woodford Aerodrome resulting in death of Avro designer Roy Chadwick.
- January 30–31, 1948 – British South American Airways’ Tudor I G-AHNP Star Tiger disappeared over western Atlantic Ocean without trace.
- January 17, 1949 – British South American Airways’ Tudor IVB G-AGRE Star Ariel vanished en route over western Atlantic.
- March 12, 1950 – Airflight Ltd’s chartered Tudor V G-AKBY Star Girl crashed approaching RAF Llandow causing eighty fatalities.
- October 26, 1951 – William Dempster Ltd’s Tudor V G-AKCC President Kruger sustained irreparable damage landing at Bovingdon.
- January 27, 1959 – Air Charter Super Trader G-AGRG El Alamein destroyed by fire during takeoff at Brindisi.
- April 23, 1959 – Air Charter Super Trader G-AGRH Zephyr crashed into Mount Suphan in Turkey.
Specifications (Avro 688 Tudor I)
See also
Notes
- ↑ Brookes 1992, p. 40.
Bibliography
- Angelucci, Enzo & Paolo Matricardi – World Aircraft – Commercial Aircraft1935–1960. London: Sampson Low Guides (1979). ISBN0-562-00125-5.
- Brookes Andrew – Disaster in the Air. London: Ian Allan Publishing (1992). ISBN978-0-7110-2037-5.
- Eastwood Tony & John Roach – Piston Engine Airliner Production List. West Drayton UK: Aviation Hobby Shop (1991). ISBN0-907178-37-5.
- Geiger Till – Britain and the Economic Problem of the Cold War. Farnham Surrey UK: Ashgate Publishing Ltd., (2004). ISBN0-7546-0287-7.
- Holmes Harry – Avro – The History of an Aircraft Company. Wiltshire UK: Crowood Press (2004). ISBN1-86126-651-0.
- Jackson A.J.– Avro Aircraft since1908, Second Edition.London: Putnam Aeronautical Books (1990). ISBN0-85177-834-8.
- Jackson A.J.– British Civil Aircraft since1919. London: Putnam & Company Ltd (1973). ISBN0-370-10006-9.
- Jane Fred T.– "The Avro688TudorI." In Jane's Fighting Aircraft of World WarII. London Studio(1946). ISBN1-85170-493-0.
- Ottaway Susan & Ian – Fly With The Stars: A History Of British South American Airways. Andover Hampshire UK: Speedman Press (2007). ISBN978-0-7509-4448-9.
- Scholefield R.A.– Manchester Airport. Stroud UK:Sutton Publishing Limited(1997). ISBN0-7509-1954-X.
- Yenne William– Classic American Airliners. St Paul Minnesota Zenith Imprint(2005). ISBN0-7603-1931-6.
External links
- Avro Tudor – Database of British Aircraft
- Tudor – British WWII Aircraft Collection
- Image of the jet-powered Tudor 8 hosted on the Internet Archive
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