Sikorsky Aircraft unveiled in early October the first of two S-97 Raider lightweight tactical helicopter prototypes. The Raider is targeted to fly by the end of 2014. In 2015 Sikorsky plans to offer the S-97 as a replacement for the U.S. Army’s OH-58D Kiowa Warrior helicopter fleet.
The program began four years ago, and since that time military budgets have dramatically dwindled. It was no doubt to the benefit of the program that it was structured as 100% industry funded to minimize funding risks. Sikorsky provided 75% of the investment, and 53 principal suppliers provided the remaining funding.
“Raider marks the first unveiling of a new relevant rotorcraft configuration in 30 years,” said Mark Miller, Vice President of Research & Engineering at Sikorsky, a subsidiary of UTC. “We kept a close eye on lowering development, production, and support costs while increasing productivity and quality. We are looking forward to getting air under its tires and expanding the envelope in flight test in the coming months.”
Based on the rotor coaxial design used in Sikorsky’s X2 technology demonstrator, the S-97 features next-generation technologies in a multi-mission configuration (armed aerial scout or light assault). The X2 not only proved its capability to reach 250 knot, it also demonstrated low pilot workload and low acoustic signature for increased survivability, says Sikorsky.
Raider is expected to improve on the X2 demonstrator by showcasing precision maneuvers in low flight speed, high g turning maneuvers at over 200 knot, hot day hover performance at altitudes up to 10,000 ft, and significant improvements in payload and flight endurance compared with conventional light tactical helicopters. Sikorsky cites that the S-97 will offer a 40% increase in payload and a 100% increase in endurance over conventional helicopters.
The fly-by-wire helicopter will feature counter-rotating rigid main rotor blades for lift and forward flight, and a pusher propeller for high-speed acceleration and deceleration. The latter feature contributes to it achieving cruise speeds up to 220 knot, more than double the speed of conventional helicopters. Dash speeds are expected to be up to 240 knot or higher.
The single-engine aircraft features a composite airframe from Aurora Flight Sciences and a maximum gross weight of slightly more than 11,000 lb.
“The Raider fuselage was designed around a set of rigorous requirements necessary for this next-generation aircraft,” said Aurora President and COO Mark Cherry. “We applied our experience developing the composite main rotor pylon for the Sikorsky-built CH-53K heavy lift helicopter, and consequently our understanding of Sikorsky’s design and manufacturing methodologies, to influence the Raider fuselage’s preliminary and detailed designs, and subsequent development of the associated tooling.”
The cockpit will fit two pilots, seated side-by-side. For armed reconnaissance and light attack missions, the 36-ft long aircraft can carry a variety of sensors and externally mounted weapons, with the flexibility to house additional fuel and ammunition for extended missions. In a light utility or special operations configuration, the cabin will carry up to six troops.
It was just May when Sikorsky first turned on electrical power to the S-97 at Sikorsky’s Development Flight Center in Florida, where the aircraft are being assembled.
The successful powering on meant that the cockpit multifunction displays and control display unit (CDU) were operational, as were the CDU controlled electronic circuit breakers. The aircraft then underwent electrical power and avionics Acceptance Test Procedures to complete the checkout of the remaining avionics, electrical, and flight control systems.
“The aircraft comes to life when power goes on,” said S-97 Program Manager Mark Hammond. He also gave a shout out to several Raider suppliers that “played a critical role in achieving the power on milestone,” including the Sikorsky Avionics Product Center, Esterline-Korry, Esterline-Mason, United Technologies Aerospace Systems, Lockheed Martin, Garmin, Avionics Instruments, BAE, Honeywell, Pacific Scientific, Northrup Grumman, Meggitt, and LMS.