Short Empire

Empire
The BOAC Short 'C' Class flying boat G-AFBL Cooee, at Rod El Farag, Egypt, c. 1946
Role Flying boat mail and passenger carrier
Manufacturer Short Brothers
Designer Arthur Gouge[1]
First flight 3 July 1936[1]
Introduction Delivered 22 October 1936,[1]
First revenue flight 6 February 1937
Retired 1946-47
Status retired
Primary users Imperial Airways/BOAC
Qantas Empire Airways
Royal Australian Air Force
Royal Air Force
Produced 1936-1940[1]
Number built 42[1]
Unit cost
£ 48,830[1]
Variants Short Mayo Composite

The Short Empire was a medium range four engined monoplane passenger and mail carrying flying boat, of the 1930s and 1940s, that flew between Britain and the British colonies in Africa, Asia and Australia as well as providing service between Bermuda and New York City. It was manufactured by Short Brothers and was developed in parallel with the Short Sunderland patrol bomber of World War II and the piggy-back Short Mayo Composite.

Design and development

The origins of the Empire boats lay in an Air Ministry requirement for passenger and mail carriers that could provide air mail service to the colonies of the British Empire in Africa and Australia.

The Empire was officially known as the C-class by Imperial Airways and each aircraft operated by them was given a name beginning with C. The first aircraft, G-ADHL Canopus, was completed in June 1936 and launched on 3 July. A total of 42 Empires were built, all at Short's Rochester factory.

Imperial Airways (and its successor BOAC), Qantas and TEAL operated the Short Empire in commercial service, while the Royal Air Force, Royal Australian Air Force, Royal New Zealand Air Force and briefly the Royal Canadian Air Force used them on military operations during the Second World War, particularly for anti-submarine patrol and transport duties.

The first series of the Short Empires, the S.23, could carry 5 crew, 17 passengers, and 4,480 lb (2,035 kg) of cargo at a maximum speed of 174 knots (320 km/h) and were powered by four 920 horsepower (690 kW) Bristol Pegasus radials.

Captain Arthur Wilcockson, who was in charge of the momentous flight of the flying boat Caledonia from Ireland to Canada, signs autograph, July 8, 1937.

The Short Empire was designed to operate along the Imperial Airways routes to South Africa and Australia, where no leg was much over 500 miles (800 km). After the design was finalized and production was started it was realized, with some pressure from the United States, that it would be desirable to offer a similar service across the Atlantic. The range of the S.23 was less than that of the equivalent US Sikorsky "Clipper" flying boats and as such they could not provide a true trans-Atlantic service. Two boats (Caledonia and Cambria) were lightened and given long range tanks and experimented with in-flight refuelling so they could make the trip but that meant they could carry fewer passengers and less cargo. In an attempt to manage the Atlantic crossing, a piggy-back approach was tried. Using the S.21 design (based on the S.23) as the carrier, with a smaller four-engined floatplane, the Short S.20, mounted on its back. Only a single example was built of the S.21 carrier aircraft, the Maia, and of the S.20 Mercury. Together they were known as the Short Mayo Composite.[2] A successful mid-air launch of Mercury was made in 1938, and it was to set a number of long distance records however a launch aircraft was required for both sides of the Atlantic and the Mercury was limited to carrying mail, and no further development of this concept occurred in the UK.

The S.30 series were fitted with the more efficient, but lower power 890 horsepower (660 kW) Bristol Perseus sleeve valve engines and had a strengthened airframe allowing the take off weight to be increased to 46,000 pounds (21,000 kg), giving a range of 1,500 miles (2,400 km). Cabot, Caribou, Clyde and Connemara were fitted with in-flight refuelling equipment and extra fuel tanks so they could be used for a regular trans-atlantic airmail service. The idea was for the aircraft to take off at lower weights and once airborne take on extra fuel to an all up weight of 53,000 pounds (24,000 kg) giving a range of over 2,500 miles (4,000 km). The extra fuel did reduce the payload to 4,270 pounds (1,940 kg) against the 6,250 pounds (2,830 kg) of the standard craft. The refuelling was by three converted Handley Page Harrow bombers, one operating out of Ireland and two out of Newfoundland. The S.33 was a further follow-on to the S.30 with the same Pegasus engine as fitted to the S.23

Initially, they were designed for a 40,500 lb gross weight but by 1939 aircraft were strengthened for 53,000 lb (24,000 kg).[3]

Wartime experience in operating at overload resulted in the realization that the Empires could take off at considerably higher weights than the conservative maxima provided by Shorts and, although the last Empire crossings to America were made in 1940 (by Clare and Clyde), many more flights were made on the long, demanding and vital over-water Lisbon-Bathurst flights.

A completely new flying boat, the S.26 "G class" was produced for year-round use on the North Atlantic route (although it was used instead between the UK and West Africa. Of similar appearance to the C-class boats but about 15% larger in all dimensions with the more powerful Hercules engines and an improved hull design, they had a wing span of 134 feet (41 m) and a length of 101 feet (31 m).

Variants

Qantas Short C Class Empire flying boat VH-ABB 'Coolangatta', ca. 1940

42 "C Class" Short Empire flying boats were built, including 31 S.23s, nine S.30s and two S.33s.[1]

Many S.23, S.30 & S.33 were re-engined during the war with 1,010 hp (750 kW) Bristol Pegasus XXII poppet valve radial engines.[1]

Service

In February 1937 Caledonia flew from Calshot to Alexandria, Egypt—some 2,500 miles (4,000 km) non-stop showing that Britain could move military materiel to its overseas bases.[4] In 1937 Caledonia was flown experimentally from Foynes on the River Shannon west to Newfoundland while an American Sikorsky S-42 flew the opposite direction. Caledonia took just over 15 hours (including a period looking for landing spot) flying at an altitude of 1,500 to 5,000 ft (460 to 1,520 m) to cover 1,993 miles (3,207 km)—an average speed of about 130 mph (210 km/h). Several more survey flights of the Atlantic were made by Caledonia and Cambria. In August 1937, Cambria made the East-West flight in 14 hrs 24 min. In 1937 Cavalier was shipped to Bermuda and after assembly started a service to New York on 25 May 1937.[5]

After Italy entered World War II in June 1940, it was impossible for mail to be flown between Britain and Egypt (and thus onto Australia) via the Mediterranean. A new "Horseshoe Route" was established that ran from Auckland/Sydney via Cairo (following the old "Eastern Route") to Durban, South Africa, and thence by sea to Britain. This was restricted after the loss of Singapore in February 1942 to being between Durban and Calcutta.

Accidents and incidents

List of aircraft

Registration Name Operator
S.23
G-ADHL Canopus Imperial Airways/BOAC
G-ADHM Caledonia Imperial Airways, later BOAC
G-ADUT Centaurus Imperial Airways, to Royal Australian Air Force (RAAF) in 1939 (as serial A18-10)
G-ADUU Cavalier Imperial Airways
G-ADUV Cambria Imperial Airways, later BOAC
G-ADUW Castor Imperial Airways, later BOAC
G-ADUX Cassiopea Imperial Airways, later BOAC
G-ADUY Capella Imperial Airways
G-ADUZ Cygnus Imperial Airways
G-ADVA Capricornus Imperial Airways
G-ADVB Corsair Imperial Airways, later BOAC
G-ADVC Courtier Imperial Airways
G-ADVD Challenger Imperial Airways
G-ADVE Centurion Imperial Airways
G-AETV Coriolanus Imperial Airways, later BOAC, to QANTAS in 1942 (as registration VH-ABG)
G-AETW Calpurnia Imperial Airways.
G-AETX Ceres Imperial Airways, later BOAC
G-AETY Clio Imperial Airways, later BOAC, to Royal Air Force (RAF) in 1940 (as AX659)
G-AETZ Circe Imperial Airways, later BOAC
G-AEUA Calypso Imperial Airways, to QANTAS in 1939 not used directly, to RAAF (as serial A18-11)
G-AEUB Camilla Imperial Airways, later BOAC, to QANTAS (as VH-ADU)
G-AEUC Corinna Imperial Airways, later BOAC
G-AEUD Cordelia Imperial Airways, later BOAC, to RAF in 1940 (as AX660), returned to BOAC in 1941 (as G-AEUD)
G-AEUE Cameronian Imperial Airways, later BOAC
G-AEUF Corinthian Imperial Airways, later BOAC
G-AEUG Coogee Imperial Airways, to QANTAS in 1938 (as VH-ABC), to RAAF in 1939 (as A18-12)
G-AEUH Corio Imperial Airways, to QANTAS in 1938 (as VH-ABD), to Imperial Airways in 1939 (as G-AEUH)
G-AEUI Coorong Imperial Airways, to QANTAS in 1938 (as VH-ABE), to Imperial Airways in 1939 (as G-AEUI)
G-AFBJ Carpentaria Imperial Airways not used, to QANTAS in 1937 (as VH-ABA), to BOAC in 1942 (as G-AFBJ)
G-AFBK Coolangatta Imperial Airways not used, to QANTAS in 1937 (as VH-ABB), to RAAF in 1939 (as A18-13)
G-AFBL Cooee Imperial Airways not used, to QANTAS in 1937 (as VH-ABF) to BOAC in 1942
S.30
G-AFCT Champion Imperial Airways, later BOAC
G-AFCU Cabot Imperial Airways, to RAF in 1939 (as V3137)
G-AFCV Caribou Imperial Airways, to RAF in 1939 (as V3138)
G-AFCW Connemara Imperial Airways
G-AFCX Clyde Imperial Airways, later BOAC
G-AFCY Captain Cook Imperial Airways, to TEAL in 1940 (as ZK-AMC Awarua)
G-AFCZ Australia then Clare Imperial Airways, later BOAC
G-AFDA Aotearoa Imperial Airways, to TEAL in 1940 (as ZK-AMA)
G-AFKZ Cathay Imperial Airways, later BOAC
S.33
G-AFPZ Clifton BOAC, to RAAF (as A18-14), to QANTAS in 1942 (as VH-ACD)
G-AFRA Cleopatra BOAC, 1st Service 5-6-40 Poole to Durban. Final Service ended 5-11-46 at Poole.

Operators

Short S.23 Cooee of Qantas—this aircraft is also pictured at the top of the page while later serving with BOAC, as G-AFBL

Civil Operators

 Australia
 New Zealand
 United Kingdom

Military Operators

 Australia
 United Kingdom

Specifications (Shorts S.23)

Data from The Encyclopedia of World Aircraft[12]

General characteristics

Performance

See also

Related development
Aircraft of comparable role, configuration and era
Related lists

References

Notes

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Cassidy, Brian (1996). Flying Empires Short 'C' class Empire flying boats. Bath, UK: Queens Parade Press. pp. 21, 54–55. ISBN 0-9529298-2-1.
  2. ↑ Robert Mayo – Short Aircraft Engineer's Concept
  3. ↑ "The Greatest Short" Flight 20 July 1939. page e
  4. ↑ Flight 15 February 1937
  5. ↑ Jackson 1974, p. 146
  6. ↑ "The Calpurnia Accident". Flight. No. 20 July 1938. p. 55.
  7. ↑ "The Mozambique Accident". Flight. No. 24 August 1939. p. 188.
  8. ↑ "BOAC Special". Aeroplane. No. April 2015 (Stamford: Key Publishing). pp. 26–49. ISSN 0143-7240.
  9. ↑ Accident description for G-ADUX at the Aviation Safety Network. Retrieved on 23 March 2015.
  10. ↑ "Circe Mystery Solved after 72 Years". australianflying.com.au. Yaffa Publishing Group. 28 February 2014. Retrieved 16 April 2014.
  11. ↑
  12. ↑ Donald, David(Editor) (1997). The Encyclopedia of World Aircraft. Aerospace Publishing. ISBN 1-85605-375-X.

Bibliography

External links

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