US-based Carson Helicopters has developed a new composite main rotor blade that enables the Sikorsky S-61 to lift an additional 900kg (2,000lb) and fly 15kt (28km/h) faster. US certification is expected this month, and Ducommun AeroStructures will produce the blades, with deliveries to begin early next year.
The blade uses new NASA aerofoils and has a swept tapered tip. "We have demonstrated a 2,000lb lift improvement with the same horsepower at sea level," says Frank Carson, president of the Perkasie, Pennsylvania-based S-61 operator. The modified helicopter can take off and land at 12,000ft (3,660m) and fly at 14,000ft, and is 40kt faster at altitude, he says.
A set of five blades is expected to cost "in the $1 million category", but will enable operators to extract significantly more performance, avoiding the $15-20 million cost of a new helicopter, says Carson. The blades will have a 20,000h life.
Carson sees a market to upgrade more than 500 commercial and military S-61s, and will upgrade its nine aircraft, used for external lift work. The new rotor will exploit the S-61's 9,980kg (22,000lb) gross-weight capability with external load.
The company is also developing a new landing gear, to increase speed by 5kt, and a new tail rotor that absorbs 25% less power and provides another 180kg of lift capability. Certification of the tail rotor is set for late 2003 or early 2004.
Source: Flight International