De Havilland D.H.114 Heron1950 |
LIGHT TRANSPORT | Virtual Aircraft Museum / United Kingdom / De Havilland |
Adopting the same philosophy that had produced the highly successful fourengined D.H.86B after the D.H.84 Dragon, de Havilland continued the success of the Dove by designing a scaled-up version designated de Havilland D.H.114 Heron. Simplicity and reliability were the keynotes for the new aircraft, which provided accommodation for a crew of two and 14 passengers (17 if no toilet was installed). Fixed tricycle landing gear eliminated the complications of a hydraulic system, and excellent short-field performance was assured by good wing design coupled with the use of variable-pitch propellers, driven by Gipsy Queen 30s which had a long operating period between overhauls. The prototype was flown for the first time on 10 May 1950. The first production Heron 1 was acquired by New Zealand National Airways, this and all subsequent aircraft having a tailplane with considerable dihedral. The seventh production example served as the prototype for the Heron 2, incorporating retractable landing gear which gave an increase in speed and a reduction in fuel consumption. This proved to be the most popular version, representing almost 70 per cent of the 150 Herons built. Despite these relatively small production figures, the Heron saw service in 30 countries, some with major airlines, many as luxury transports (including four operated by The Queen's Flight at RAF Benson), and about 25 of the total were used as communications aircraft by nine military services. In their later years Herons were the subject of a number of modification programmes, the Riley Turbo Skyliner produced by the Riley Turbostream Corporation in the USA being typical of reengined aircraft. This replaced the standard powerplant by 216kW Avco Lycoming IO-540 engines, with or without turbochargers according to customer requirements. Far more ambitious was the conversion carried out by Saunders Aircraft Corporation of Gimli, Manitoba. Designated Saunders ST-27, this had a fuselage lengthened by 2.59m to provide accommodation for a maximum of 23 passengers, the wing rebuilt to incorporate a redesigned main spar and the four Gipsy engines replaced by two 559kW Pratt & Whitney Aircraft of Canada PT6A-34 turboprop engines. A total of 12 ST-27 conversions was completed and the prototype of an improved ST-28 was built before Saunders went into receivership.
| COMPANY PROFILE | |||||||||||||||||||||||||||||||||||||||||||||||||||||||