Airspeed Ambassador

AS.57 Ambassador
Dan Air Ambassador at Bristol Airport in 1965
Role Airliner
Manufacturer Airspeed Ltd
First flight 10 July 1947
Introduction 1951
Primary user British European Airways
Produced 1947–1953
Number built 23

The Airspeed AS.57 Ambassador was a British twin piston-engined airliner that first flew on 10 July 1947 and served in small numbers through the 1950s and 1960s. The planes are sometimes referred to as "Elizabethans", as they were originally ordered and popularized by British European Airways as the planes used for their "Elizabethan Class" passenger service.

Design and development

The Ambassador had its origin in 1943 as a requirement identified by the Brabazon Committee for a twin-engined short-to-medium-haul replacement for the Douglas DC-3. Airspeed Ltd. was asked to prepare an unpressurised design in the 14.5-ton gross weight class, using two Bristol Hercules radial engines. In 1943, the company duly set up a dispersed design office in Fairmile Manor at Cobham in Surrey.

By the time the British Ministry of Aircraft Production ordered two prototypes from Airspeed, immediately after the end of the Second World War, the design had grown substantially. The Ambassador would be pressurised, have more powerful Bristol Centaurus radials and have a maximum gross weight of almost 24 tons.

The revised design offered seating for 47 passengers and, having a tricycle undercarriage, looked more modern than the DC-3s, Curtiss Commandos, Avro Lancastrians and Vickers Vikings that were common on Europe's shorter airline routes. With three low tailfins and a long pointed nose, it shared something of the character of the larger transcontinental Lockheed Constellation.

Great efforts were made to reduce drag, to improve performance and cruising efficiency. The engine nacelles were first designed with inwardly opening louvres for exhaust gases and cooling air rather than the usual outwardly opening "gills". However, these proved inadequate to cool the engine, so the gills were reinstated.[1]

Operational history

Three prototypes were built, the first registered G-AGUA was first flown by George B.S. Errington from Christchurch on 10 July 1947.[2] British European Airways (BEA) placed a £3 million order for 20 aircraft in September 1948, and operated them between 1952 and 1958, calling them their "Elizabethan Class" in honour of the newly crowned Queen.[2] The flagship of the fleet was G-ALZN, appropriately named "RMA Elizabethan". The first "Elizabethan" scheduled flight was from Heathrow to Paris Le Bourget on 13 March 1952 and the type later also served the key UK routes. By December 1955 the "Elizabethan Class" had reached 2,230 flying hours annually, per aircraft, the highest in BEA's fleet. However, the last Elizabethan scheduled service for BEA was operated in August 1958, and the type was replaced by the Vickers Viscount.

Napier's Eland engine test-bed Ambassador G-ALFR at Farnborough SBAC Show 1955

After disposal by BEA, the type helped to establish the scheduled and charter flight operations of Dan-Air, an important airline in the development of package holidays. The type was also used in the UK by Autair and BKS Air Transport. Second-hand Ambassadors were flown for short periods by Butler Air Transport (Australia), Globe Air (Switzerland) and Norrønafly (Norway).[3]

The second Ambassador 2 G-AKRD was used by the Bristol Aeroplane Company from 1953 for the flight testing of the Bristol Proteus 705 turbine engine. From March 1958 G-AKRD was used by Rolls Royce for proving the Tyne turboprop. The first Ambassador 2 G-ALFR was used from 1955 in the development trials of the Napier Eland turbine engine.

The popularity of this aircraft, with its pressurised cabin and good soundproofing, was soon eclipsed by the arrival of turboprop-powered aircraft such as the Vickers Viscount and, some years later, the Lockheed Electra, which featured more reliable engines and faster speeds. The coming of turboprops and the dawning of the jet age caused the Ambassador to fall out of favour, along with negative publicity arising from two fatal crashes.

Variants

BKS Air Transport Ambassador G-AMAD in 1965
AS.57 Ambassador 1
Prototype aircraft with Bristol Centaurus engines, two built.
AS.57 Ambassador 2
Production aircraft, 21 built.

Projects

AS.59 Ambassador II
Project for either a twin-engined variant with Bristol Proteus or Bristol Theseus engines or a four-engined variant with Napier Naiads or Rolls-Royce Darts.[4] From the first prototypes, the Ambassador's wing had been stressed for four engine points, but no four-engined variant flew.[5]
AS.60 Ayrshire C.1
Proposed variant to meet Air Ministry Specification C.13/45 for a medium-range military transport.[4] Ten were ordered in October 1946 but were not built, after a review of the design's projected performance produced figures lower than the Air Ministry's requirements.[6]
AS.64
Proposed military transport variant for the Royal Air Force to meet Air Ministry Specification C.26/43, not built.[4]
AS.66
Proposed civil freighter variant.[4]
AS.67
Proposed civil freighter variant.[4]

Accidents and incidents

Operators

Civil operators

 Australia
 Norway
 New Zealand
  Switzerland
 United Kingdom
BEA "Elizabethan" G-AMAG "Sir Thomas Gresham" at Manchester (Ringway) Airport on the schedule to Heathrow in July 1953

Military operators

 Jordan
 Morocco

Aircraft on display

One Elizabethan, Christopher Marlowe (G-ALZO, c/n 5226), survives and is under long term major restoration by the Duxford Aviation Society at the Imperial War Museum, Duxford near Cambridge.

Specifications

Airspeed Ambassador

Data from Jackson 1959, p. 30

General characteristics

Performance

See also

Aircraft of comparable role, configuration and era

Related lists

References

Notes
  1. ↑ Boot, pp.25-26.
  2. 1 2 Singfield 2000, p. 12.
  3. ↑ Jackson 1973, pp. 395–396.
  4. 1 2 3 4 5 "Airspeed Type Designations." Flight International, 23 February 1951, p. 228.
  5. ↑ Boot, p.25
  6. ↑ Boot, p.24
  7. 1 2 3 Eastwood and Roach 1991, p. 7.
  8. ↑ "Accident description: Airspeed AS.57 Ambassador 2, 8 April 1955." Aviation-safety.net. Retrieved: 13 November 2010.
  9. ↑ "Accident description: Airspeed AS.57 Ambassador 2, 6 February 1958." Aviation-safety.net. Retrieved: 6 May 2012.
  10. ↑ "Accident description: Airspeed AS.57 Ambassador 2, 3 July 1968." Aviation-safety.net. Retrieved: 6 May 2012.
  11. ↑ "Accident description: Airspeed AS.57 Ambassador 2, 30 September 1968."Aviation-safety.net. Retrieved: 13 November 2010.
Bibliography
  • Boot, Roy. From Spitfire to Eurofighter: 45 years of Combat Aircraft Design. Shrewsbury, UK: AirLife Publishing, 1990. ISBN 1-85310-093-5.
  • Eastwood, Tony and John Roach. Piston Engine Airliner Production List. West Drayton, UK: The Aviation Hobby Shop, 1991. ISBN 0-907178-37-5.
  • Jackson, A.J. British Civil Aircraft since 1919 Volume 1. London: Putnam, 1974. ISBN 0-370-10006-9.
  • Jackson, A.J. British Civil Aircraft since 1919 Volume 1. London: Putnam, 1959.
  • James, Derek. "Database: Airspeed Ambassador". Aeroplane Monthly. Volume 31, Issue 04, April 2003
  • Singfield, Tom. Classic Airliners. Leicester, UK: Midland Publishing, 2000. ISBN 1-85780-098-2.
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