De Havilland Hercules
| Industry | Aircraft manufacturing |
|---|---|
| Founded | 1920s |
| Headquarters | United Kingdom |
| Products | Aircraft including the DH.66 Hercules |
The de Havilland DH.66 Hercules was a British trimotor airliner from the 1920s, designed to carry seven passengers and constructed by the de Havilland Aircraft Company. This model marked Imperial Airways' assumption of the airmail route previously managed by the Royal Air Force, which had been using the outdated Airco DH.10 Amiens.
Serving as a long-range transport option, the Hercules enabled Imperial Airways to connect distant locations. Despite its modest speed, it laid important groundwork for the development of future commercial aircraft.[1]
Design and development
The Hercules was conceived specifically for Imperial Airways as they took over operation of the Cairo–Baghdad air route from the Royal Air Force. This three-engine, two-bay biplane featured accommodation for seven passengers along with mail transport capabilities. The inclusion of three engines was intended to minimize the risk of forced landings when flying over isolated desert terrain. To combat deterioration in tropical environments, the fuselage employed a tubular steel frame with plywood forming the cabin and rear luggage compartments.[2] The pilots operated from an open cockpit positioned above the aircraft's nose, while inside the cabin there was space for a wireless operator alongside seven passengers.[2]
Imperial Airways secured a five-year contract to manage the Cairo to Baghdad airmail service and was also tasked with commencing flights between Cairo and Karachi. To meet these demands, an order for five Hercules aircraft was placed. In June 1926, prior to completion of the prototype, the name Hercules was selected through a competition held in Meccano Magazine. The prototype's maiden flight took place on 30 September 1926 at Stag Lane Aerodrome.[2]
In 1929, four units were produced for West Australian Airways, incorporating modifications tailored to Australian conditions such as an enclosed cockpit and seating capacity increased to 14 passengers, while still retaining space for mail and baggage.[2]
That same year, two more Hercules aircraft were manufactured for Imperial Airways featuring enclosed cockpits; earlier models were subsequently retrofitted with this upgrade.[2]
Operational history
- Imperial Airways
After completing crew training, the prototype departed the United Kingdom on 18 December 1926, heading to Cairo where it was stationed at Heliopolis. The second unit left Croydon bound for Cairo on 27 December 1926, transporting the Secretary of State for Air, Samuel Hoare. It continued its journey to India, reaching Delhi on 8 January 1927. The prototype, subsequently named City of Cairo by King Fuad, inaugurated the first commercial route between Basra and Cairo on 7 January 1927. However, operations to Karachi only commenced two years later after receiving approval from the Persian Government.[2]
In 1929, with the launch of the Cairo to Delhi route, a sixth Hercules aircraft named City of Basra was introduced.[2] Following the tragic crash of the City of Jerusalem in September 1929, a seventh new plane was ordered and delivered in January 1930. Since production had ceased by then, when the City of Tehran was destroyed after a forced landing, Imperial Airways acquired a replacement from West Australian Airways.[2]
During 1931, two trial air mail routes were established between Croydon, England and Melbourne, Australia. The City of Cairo was tasked with carrying mail from Karachi to Australia but had to make an emergency landing at Koepang on 19 April 1931 due to fuel exhaustion.[lower-alpha 1] Imperial Airways again procured an aircraft from West Australian Airways; this plane carried the inaugural through mail from Australia to England during its delivery flight to Karachi.[2]
In December 1931, the former West Australian Airways aircraft City of Cape Town undertook a survey flight towards Cape Town in anticipation of extending the Empire Air Route to South Africa. From October 1932 until 1933, Sir Alan Cobham utilized the City of Cape Town briefly in South Africa for his traveling air show. The City of Jodhpur participated in an aerial anti-locust operation over Rhodesia in 1934 but crashed into a swamp near Lake Salisbury in Uganda the following year and was destroyed. Between 1934 and 1935, Imperial Airways retired the Hercules fleet; three units were sold to the South African Air Force.[2]
- South African Air Force
In 1935, three Hercules aircraft were purchased by the South African Air Force from Imperial Airways[lower-alpha 2]. With the outbreak of World War II, these planes served as military transports supporting South African troops across Africa. One was dismantled for spare parts in 1939, while the remaining two were withdrawn and scrapped by 1943.[2]
- Stephens Aviation
Two former West Australian Airways planes—the City of Perth and the City of Adelaide—were employed on a ferry route in New Guinea operating between Lae and Wau starting in 1936. The City of Perth crashed in February 1941, and the City of Adelaide was destroyed due to enemy action in 1942.[2]
- West Australian Airways
West Australian Airways placed orders for four Hercules aircraft intended for a new passenger and mail route connecting Perth and Adelaide. After undergoing acceptance trials in England, these four planes were shipped to Perth and assembled locally. The initial eastbound service was conducted by two aircraft—the City of Adelaide and the City of Perth. They reached Perth on 29 May 1929 after covering 1450 miles within 14 hours. Subsequently, two units were sold to Imperial Airways while the remaining pair were transferred to Stephens Aviation following the acquisition of West Australian Airways by Australian National Airways.[2]
Operators
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Accidents and incidents
- On 6 September 1929, a DH.66 Hercules operated by Imperial Airways, bearing the registration G-EBMZ, crashed while attempting to land at Jask in Iran. The accident, attributed to pilot error, resulted in three fatalities out of the five occupants.[4]
- On 14 February 1930, an Imperial Airways DH.66 Hercules with registration G-EBNA was irreparably damaged following a forced landing in Gaza, Egypt.[5]
Specifications (DH.66A)
See also
References
Notes
- ↑ The mail was subsequently retrieved and transported to Darwin, Australia by Charles Kingsford Smith aboard the Southern Cross
- ↑ At a cost of £775 each
Citations
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- ↑ Template:ASN accident
- ↑ Template:ASN accident
Bibliography
- The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985). London: Orbis Publishing, 1985.
- Jackson, A.J. British Civil Aircraft since 1919, Volume 2. London: Putnam, 1974. ISBN 0-370-10010-7.
- Jackson, A.J. De Havilland Aircraft since 1909. London: Putnam, 1987. ISBN 0-85177-802-X
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- 1920s British airliners
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