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Sikorsky has unveiled a sleek, beefed-up version of its S-97 Raider coaxial compound helicopter specifically designed for the U.S. Army’s Future Attack Reconnaissance Aircraft (FARA) competition.
Keeping with the company’s lineage of experimental rotorcraft, the new aircraft is called the Raider X and is a direct descendent of the S-97 Raider that has been in test for several years. The new concept retains the basic coaxial main rotor configuration with an aft pusher propulsor, but is 20 percent larger than the S-97.
Where the S-97 has a 34-foot (10.4-meter) main rotor diameter and is built around a GE YT706 engine, its evolutionary descendant will have a 39-foot (11.9-meter) main rotor diameter and be built to accept the GE T901 engine the Army has prescribed for FARA, according to Tim Malia, Sikorsky’s FARA program director.
Though it holds a $940 million initial design development contract to produce a FARA concept, Sikorsky is further along the development curve than any of its competitors. The S-97, which has been in flight test since 2015, is being employed as an 80-percent scale model of the new, larger Raider X.
Sikorsky unveiled the Raider X design Oct. 14 at the Association of the U.S. Army’s annual conference (AUSA) in Washington, D.C. Just a few hundred feet away are full-scale mockups of FARA aircraft pitches by Bell and AVX/L3, both of which are in initial design. A Karem/Northrop Grumman/Raytheon team has gone public with its pitch, but also is in the design development stage. Boeing has said next to nothing about its pitch, but insists it is heavily into design development and buying up long-lead time materials to build a prototype.
By contrast, Sikorsky has four years of what it says are highly representative flight test data from the S-97 Raider, which was initially designed to now defunct Army requirements for an Armed Aerial Scout Helicopter. No worry, says chief test pilot Bill Fell. The company can comfortably lean on its experience with the smaller S-97, to the point he and other Sikorsky officials are using that operational prototype almost as an interchangeable stand-in for its eventual FARA prototype.
“We’re not in Powerpoint,” Malia told reporters Oct. 14. “We’re not putting Bondo on plywood.”
Raider X increases the weight of the aircraft from about 12,000 pounds to 14,000 pounds (5,445 to 6,350 kilograms), Malia said. It features a side-by-side cockpit, which also widens the fuselage to increase its internal weapon storage.
Carrying weapons internally reduces drag and allows the aircraft to achieve speeds well above the Army’s 180-knot requirement. Raider has already flown 207 knots in level flight and 250 in a shallow dive. The larger, more powerful Raider X should be able to fly faster than that, Fell said.
“We’re going from a 12,000-pound Raider to a 14,000-pound Raider by upsizing everything just a little bit,” Fell said. “We’re flying and collecting detailed flight test data on a fully instrumented aircraft. We know what the loads are. We know what the vibration characteristics are. We know what the power required is. We know what the performance of this aircraft is, so the relative risk is really low as we go to a slightly upsized Raider X going into the FARA program.”