| DH.66 Hercules | |
| Type: | Airliner |
| National Origin: | United Kingdom |
| First Flight: | 30 September 1926 |
| Introduction: | 1926 |
| Retired: | 1942 |
| Number Built: | 11 |
| More Users: | West Australian Airways South African Air Force |
The de Havilland DH.66 Hercules was a British 1920s seven-passenger, trimotor airliner built by de Havilland Aircraft Company. With the Hercules, Imperial Airways took over responsibility for the airmail service from the Royal Air Force, which had been operating the obsolete Airco DH.10 Amiens.
The Hercules effectively provided long-distance service to far-flung regions for Imperial Airways. Although slow, they pointed the way for future airliners.[1]
The Hercules was designed for Imperial Airways when it took over the Cairo–Baghdad air route from the Royal Air Force. The Hercules was a three-engine two-bay biplane with room for seven passengers and the ability to carry mail. Using three engines reduced the risk of forced landings over remote desert areas. To reduce the risk of deterioration in tropical areas the fuselage was a tube steel frame, with the cabin and rear baggage compartment of plywood mounted inside it. The two pilots were in an open cockpit above the nose while the cabin had room for a wireless operator and seven passengers.
With a contract for five years to run the Cairo to Baghdad air mail service, and a requirement to start a service between Cairo and Karachi, Imperial Airways ordered five aircraft. In June 1926, while the prototype was still being built, the type name Hercules was chosen in a competition in the Meccano Magazine. The prototype first flew on 30 September 1926 at Stag Lane Aerodrome.
Four were built in 1929 for West Australian Airways with modifications to meet Australian requirements including an enclosed cockpit and seating for 14 passengers while retained space for mail and baggage.
Two additional aircraft were built for Imperial Airways in 1929 with the enclosed cockpit, which were retro-fitted to the earlier aircraft.
With the start of the service between Cairo and Delhi in 1929 a sixth Hercules, the City of Basra entered service. With the fatal loss of the City of Jerusalem in September 1929 a seventh new aircraft was ordered and delivered in January 1930. With the aircraft now out of production when the City of Tehran forced-landed and was destroyed, Imperial Airways bought an aircraft from West Australian Airways to replace it.
In 1931 two experimental air mail services between Croydon, England and Melbourne, Australia were attempted. The City of Cairo was to fly the mail from Karachi to Australia but ran out of fuel and forced landed at Koepang on 19 April 1931. West Australian Airways was approached again and another aircraft was sold to Imperial Airways. On the delivery flight to Karachi it carried the first through Australia to England mail.
In December 1931 the former West Australian Airways, City of Cape Town operated a survey flight to Cape Town pending the extension of the Empire Air Route to South Africa. The City of Cape Town was briefly used in South Africa from October 1932 until 1933 by Sir Alan Cobham for his itinerant air pageant. The City of Jodhpur was used in an aerial ant-locust campaign in Rhodesia in 1934 and the following year it crashed into a swamp near Lake Salisbury in Uganda and was destroyed. Imperial withdrew the Hercules from service between 1934 and 1935; three were sold to the South African Air Force.
South Africa