Development
The development of the S-76 began in the mid-1970s as the S-74, with the design goal of providing a medium helicopter for corporate transportation and the oil drilling industry; the S-74 was later re-designated the S-76 in honor of the U.S. Bicentennial. Sikorsky's design work on the S-70 helicopter (which was selected for use by the United States Army as the UH-60 Black Hawk) was utilized in the development of the S-76, incorporating S-70 design technology in its rotor blades and rotor heads. It was the first Sikorsky helicopter designed purely for commercial rather than military use.
The prototype first flew on March 13, 1977. Initial US Federal Aviation Administration type certification was granted on November 21, 1978, with the first customer delivery on February 27, 1979. The S-76 was named "Spirit" late in 1978, but this name was officially dropped by the company on October 9, 1980 due to translation issues into some foreign languages.
The first production variant was the S-76A. In 1982, this model set class records for range, climb, speed and ceiling. Several airlines operate the S-76A on scheduled services including Helijet Airways of Vancouver, British Columbia, Canada. The S-76 Mk II was introduced in 1982 and the S-76B in 1987, with its top speed of 155 kn (287 km/h) at sea level. Over 500 S-76s had been delivered by early 2001.
The S-76C+ was produced until December 2005. It is equipped with twin Turboméca Arriel 2S1 engines with FADEC and a Honeywell EFIS suite. The aircraft incorporates active noise suppression, vibration dampers and a composite main rotor. On January 3, 2006, the S-76 C++ replaced earlier models in production. It is powered by two Turbomeca Arriel 2S2 engines and incorporates an improved and quieter transmission as well as minor changes in the interior equipment and avionics. There were 92 orders for this model as of January 2006.
Development of the follow-on S-76D has been subject to delays due to technical problems in expanding the flight envelope. It is to be powered by 1,050 hp (783 kW) Pratt & Whitney Canada PW210S engines driving composite rotors and will incorporate active vibration control. A prototype made its first flight on 7 February 2009 and type certification was initially expected in 2011, with deliveries forecast for the end of that year. Three prototypes will be used in the certification program. One aircraft will be used to obtain certification of an optional electric rotor ice-protection system. Performance is anticipated to be substantially improved with the added power, but initial certification will retain the same 11,700 lb (5,307 kg) gross weight and maximum 155 kn (287 km/h) cruise speed.
Read more about this topic: Sikorsky S-76
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