Latest C++ variant to be quieter, with new interior, while changes to the S-76D revolve around new turboshaft
Sikorsky has revealed more details of the extensive upgrade under way for the new S-76C++ helicopter, and has launched a competition to supply the cockpit of the newly launched S-76D model.
Deliveries of the S-76C++ will begin later this year, says Jeff Pino, Sikorsky senior vice-president sales and commercial programmes. Pricing remains the same as for the S-76C+, says Pino, who adds that customers "want more for the same price". The biggest single change is the move to the uprated Turbomeca Arriel 2S2 turboshaft, which will have up to a 6% higher rating, allowing for a 160-205kg (350-450lb) increase in Category A take-off gross weight at sea level and temperatures up to 32¡C (90¡F).
A new inlet barrier filter (IBF) system, co-developed with Turbomeca, will also be a part of the upgrade. Sikorsky says that unlike many other inlet protection systems the flow through the IBF has been designed to reduce engine degradation without the power loss normally encountered. The IBF is expected to result in longer time between overhauls, fewer removals and lower costs.
The S-76C++ will also be equipped with the Honeywell VXP health and usage monitoring system, which will provide rotor track and balance, drive system monitoring and a high-speed shaft monitoring option. Sikorsky's "Quiet Zone Technology" low noise gearbox, which reduces cabin noise by 4dB while increasing gear life and durability, will also be fitted. The technology associated with the advanced gear is focused on the smooth finish and modified shape of the intermeshing parts in the transmission.
The latest variant of the S-76, the 615th of which has now been delivered, will also have a new interior with a three-person aft-facing bench and two forward-facing seats coupled with an improved soundproofing system using Keystone's Silencer noise suppression cocoon.
Sikorsky is also competing the cockpit for the new S-76D, which will be available from mid-2008. Contestants include CMC, Honeywell, Kollsman, L-3, Rockwell Collins and Thales. "They're all bidding, and we expect to pick the winner quickly," says Pino.
Key design changes to the S-76D, which will have a streamlined exterior, revolve around its new Pratt & Whitney Canada PW210S turboshaft (Flight International, 15-21 February) and an all-composite main rotor blade. The combination is expected to provide an extra 635kg of lifting capacity in hot-and-high conditions, says Pino.
The new blade design will draw on the RAH-66 Comanche's "Generation 3" rotor, and will be a scaled-down derivative of the newer-generation aerofoil used on the upgraded UH-60M.
The tailrotor is also being redesigned to cut noise by 2dB for take off and 1.5dB for flyover.
GUY NORRIS / LOS ANGELES
Source: Flight International
