The DH.114 Heron is a
stretched, four engined development of de Havilland's successful DH.104
Dove.
Only a few years later in development than the Dove on which it was
based, design work on the Heron began in the late 1940s, resulting in
the prototype's first flight on May 10 1950 (the Dove first flew in
1945). In designing the Heron, de Havilland made as much use of Dove
components as possible, and so both types feature the distinctive
slightly raised cockpit and separate main cabin and metal construction.
Initial Heron production aircraft also featured fixed undercarriage
(unlike the retractable gear Dove). Major differences include the four
185kW (250hp) Gipsy Queen engines (as opposed to two 255 to 300kW/340
to 400hp Gipsy Queen 70s), greater span wings, a longer and taller
fuselage and greater seating capacity. The first Series 1 production
Herons were delivered to New Zealand National Airways in 1952.
Also in 1952 the first Series 2 Heron first flew on December 14. The
2's main improvement over the 1 was retractable undercarriage, which
for a weight penalty of 75kg (165lb) increased cruising speed by 32km/h
(17kt), while other standard and optional improvements were minor in
nature. The Heron 2A was certificated for use in the USA, and an
equivalent 2B executive version was also offered. The 2C and equivalent
executive 2D have greater weights.
The Heron has been the subject of numerous conversion programs. In the
USA Riley converted 20 to be powered by Lycoming IO540s (eight more
were converted in Australia), while Prinair converted a further 29 to
Lycoming power.
The most ambitious Heron conversions were performed by Saunders, whose
ST27 conversions feature two Pratt & Whitney Canada PT6 turboprops and
a stretched fuselage. In addition, Tawron converted six Series 1 Herons
with Continental engines.
The Year: 1952
Crew: 2
Engines: 4 of 186kW D.H. Gipsy Queen 30-2
Wing Span: 21.79m Length: 14.78m Height: 4.75m Wing Area: 46.36m2
Empty Weight: 3697kg
Max. Weight: 6123kg
Speed: 294km/h
Ceiling: 5640m
Range: 1473km
Load: 15-17 seats. |