De Havilland DH 114 Heron
Sea Heron C.4
de Havilland continued the success of the Dove by designing a scaled-up version designated de Havilland D.H.114 Heron. The new aircraft provided accommodation for a crew of two and 14 passengers (17 if no toilet was installed). Fixed tricycle landing gear removed the complications of a hydraulic system, Gipsy Queen 30s and variable-pitch propellers. The prototype was flown for the first time on 10 May 1950.
The Heron is equipped to seat 14 passengers in single seats on each side of the central aisle. Four 250 hp Gipsy Queen six-cylinder inline direct drive normally aspirated engines are fitted with bracket type constant-speed two-blade airscrews.
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. This proved to be the most popular version, representing almost 70 per cent of the 150 Herons built.
The New Zealand National Airways Corp owned four during 1952-60; ZK-AYV Matuku; ZK-BBN Motuhi; ZK-BEQ Mako; ZK-BBM Matmpouri.
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.
British European Airways Herons were used to maintain the BEA Ambulance Service in Scotland and the islands around the coast.
BEA Heron landing on the beach at Bora, Scotland circa 1955
The Riley Turbostream Corporation in the USA produced the Riley Turbo Skyliner. This replaced the standard engines with 290 hp / 216kW Avco Lycoming IO-540-G1A5 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.
Franciso J. Waltz, Mexico City, produced in 1959 a high-altitude conversion of de Havilland Heron with 340 hp Lycoming engine for Mexican use under name Waltz Super Heron.
DH 114-1B Heron
Engines: 4 x Gipsy Queen 39
Wingspan: 71 ft 6 in / 21.8 m
Length: 48 ft 6 in / 14.78 m
Max speed: 190 mph / 306 kph
Passenger capacity: 14
DH 114 Heron 2D
Engines: 4 x de Havilland Gipsy Queen 30-2 inline, 186kW, 247 hp
Max take-off weight: 6123 kg / 13499 lb
Empty weight: 3697 kg / 8151 lb
Wingspan: 21.79 m / 71 ft 6 in
Length: 14.78 m / 48 ft 6 in
Height: 4.75 m / 15 ft 7 in
Wing area: 46.36 sq.m / 499.01 sq ft
Max. speed: 165 kts / 306 kph
Cruise speed: 295 km/h / 183 mph
Ceiling: 5640 m / 18500 ft
Initial climb rate 1,075 fpm
Takeoff distance (50') 2,424 ft.
Landing distance (50') 2,065 ft.
Range w/max.fuel: 1813 km / 1127 miles
Range w/max.payload: 645 km / 401 miles
Passengers: 14-17 / 1385Kg
Engines: 4 x Lycoming IO-540-G1A5, 290 hp.
Cruise: 170-175 kt.
Endurance: 7.5 hr.
Pax cap: 15.