Sikorsky S-61N
| S-61L/S-61N | |
|---|---|
 |
|
| A S-61N Mk.II operating for Sociedad de Salvamento y Seguridad Marítima | |
| Role | Medium-lift transport / airliner helicopter |
| Manufacturer | Sikorsky Aircraft |
| First flight | March 11, 1959 |
| Introduction | September 1961 |
| Status | Active service |
| Primary users |
CHC Helicopter Bristow Helicopters AAR Airlift |
| Number built | 119 |
| Developed from | SH-3 Sea King |
The Sikorsky S-61L and S-61N are civil variants of the successful SH-3 Sea King helicopter. They are two of the most widely used airliner and oil rig support helicopters built.
In September 1957, Sikorsky won a United States Navy development contract for an amphibious anti-submarine warfare (ASW) helicopter capable of detecting and attacking submarines. The XHSS-2 Sea King prototype flew on 11 March 1959. Production deliveries of the HSS-2 (later designated SH-3A) began in September 1961, with the initial production aircraft being powered by two 930 kW (1250shp) General Electric T58-GE-8B turboshafts.
Sikorsky was quick to develop a commercial model of the Sea King. The S-61L first flew on 2 November 1961, and was 4 ft 3 in (1.30 m) longer than the HSS-2 in order to carry a substantial payload of freight or passengers. Initial production S-61Ls were powered by two 1350shp (1005 kW) GE CT58-140 turboshafts, the civil version of the T58. The S-61L features a modified landing gear without float stabilisers.
Los Angeles Airways was the first civil operator of the S-61, introducing them on 11 March 1962, for a purchased price of $650,000 each.
On 7 August 1962, the S-61N made its first flight. Otherwise identical to the S-61L, this version is optimized for overwater operations, particularly oil rig support, by retaining the SH-3's floats. Both the S-61L and S-61N were subsequently updated to Mk II standard with improvements including more powerful CT58-110 engines giving better hot and high performance, vibration damping and other detail refinements.
The Payloader, a stripped down version optimised for aerial crane work, was the third civil model of the S-61. The Payloader features the fixed undercarriage of the S-61L, but with an empty weight almost 2,000 lb (910 kg) less than the standard S-61N.
Carson Helicopters was the first company to shorten a commercial S-61. The fuselage is shortened by 50 in (1.3 m) to increase single-engine performance and external payload.
A unique version is the S-61 Shortsky conversion of S-61Ls and S-61Ns by Helipro International. VIH Logging was the launch customer for the HeliPro Shortsky conversion which first flew in February 1996.
One modification for the S-61 is the Carson Composite Main Rotor blade. These blades replace the original Sikorsky metal blades which are prone to fatigue. The Carson Composite Main Rotor blades permit a modified aircraft to carry an additional 2,000 lb (907 kg) load, fly 15 kn (28 km/h) faster and increase range 61 nmi (113 km).
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Wikipedia