Military

Sikorsky Using Raider to Refine Future Army Attack Aircraft Design

By Dan Parsons | June 25, 2019
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WEST PALM BEACH, Fla. — Sikorsky, now testing its S-97 Raider compound helicopter weekly, has transitioned the aircraft to a team focused on creating the company’s Future Attack Reconnaissance Aircraft (FARA) offering.

The compound helicopter, one of two Sikorsky built initially to satisfy the Army’s need for an armed scout helicopter to replace the OH-58D Kiowa Warrior, now has 55 total flight hours. It has flown to 207 knots in level cruise flight, performed 60-degree banks and risen to 8,000 feet.

Having graduated from being solely a developmental prototype, the Raider is now assigned to the FARA team, which is using it as a real-world test bed for risk reduction as the formal Army program approaches.

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Sikorsky formally kicked off its FARA program in January and is in the process of “optimizing the design” of the aircraft it eventually will pitch the Army. The company has not made its FARA design public, but Raider is “very representative” of what will be offered, said Chris Van Buiten, vice president of Sikorsky Innovations.

“We've essentially transitioned the asset to the FARA team to execute risk reduction for FARA,” Van Buiten said before a June 25 demo flight of Raider for reporters and suppliers here. “What are the most critical things? Risk items we can burn down. What's the most valuable data we can give them? And um, you know, we're not going to get into the details of our FARA offer, but this vehicle is very relevant in terms of its sizes, towers and attributes and 207 knots is the objective.”

Raider is flying almost weekly and at up to 180 knots — well past the sprint speed of a conventional helicopter — on almost every outing, said Chief Test Pilot Bill Fell. The goal was to fly at 220 knots, but the aircraft might not make that benchmark in its current configuration, Fell said.

“We’re not done by any means,” Fell said. “We’re still turning dials.”

Those “dials” are everything from the fly-by-wire controls software to continuing drag reduction of various airframe parts, Fell said. During the June 25 demo flight, the test card called for a 200-knot pass that was performed at about 190 knots because a piece of vibration control software did not provide the proper characteristics to go faster, he said. The software will be tweaked and retested as the team continues its search for speed.

Sikorsky is one of five bidders for FARA — the others are Bell, an AVX-L3 team, Boeing, and Karem Aircraft — the Army selected for competitive prototyping contracts. The service is scheduled to choose two aircraft for a competitive prototyping effort that should result in an aircraft to fill the operational gap left by retirement of the OH-58D. FARA also will replace a portion of the Army’s AH-64 Apache fleet.

Like Sikorsky, most of the competitors have played their FARA designs very close to the vest, going public only with general characteristics and technologies that likely will be incorporated. But unlike the rest, Sikorsky has been flying Raider for more than two years. A hard landing of the first flying airframe caused by an autopilot software miscue grounded the program for nearly a year, but the company is leaps ahead of the competition in gathering data on a speedy compound helicopter in the 14,000-pound weight class.

Sikorsky’s FARA Director Tim Malia said teams based at various facilities since January have had almost direct access to the S-97 and its test team as they collaboratively develop the company’s FARA design.

Now, if FARA engineers need data on, say, Raider’s performance characteristics during a 3-G turn, the team can have the maneuver written into a flight card and have data in a matter of days, Malia said.

“Normally, when you start with a clean-sheet aircraft, you have to guess at all that stuff,” he said.

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