For , demonstrating the S-97 Raider high-speed helicopter is even more important now that the U.S. Army has decided to retire its armed scout helicopters and not replace them, at least in the near term.
The company, which is building two Raider prototypes on industry funds, believes there is still room, and time, within the Army's long-term budget to acquire a small fleet of new armed scouts before it begins the heavy expenditure of replacing its large fleets of medium-utility and attack helicopters.
Whether wishful thinking or canny planning, the key to making this version of the future a reality is demonstrating the combat capabilities that the rigid coaxial-rotor Raider's high speed and maneuverability will bring to the battle.
And the stakes are even higher than just carving out a budget niche for an armed scout—building and flying the Raider is a key step in reducing the risk in the similarly configured Sikorsky/Defiant—which is competing to be one of two advanced rotorcraft to fly in 2017 under the Army's Joint Multi Role (JMR) technology demonstration.
JMR is a precursor to the planned Future Vertical Lift (FVL) Medium program to replace theBlack Hawk utility and Boeing AH-64 Apache attack helicopters that make up the bulk of the Army's rotary-wing fleet.
As a result, rather than deflate Sikorsky's plans, the Army's decision to abandon its Armed Aerial Scout (AAS) procurement has added determination to the rapid-prototyping effort underway here, where the first Raider is 25% complete and on track to fly by year-end.
“We believe there is room to get AAS into the inventory before FVL in 2034,” says Steve Engebretson, Sikorsky armed aerial scout program director. “By late 2015 we will be able to give the Army a data package that will enable them to launch a competition with a request for proposals in 2017 and a contract in 2018.
“We can develop the aircraft in 10 years and field it in 2028. That will give us six years, to 2034, to build 50-60 a year to meet a 300-350 aircraft requirement. It is a pretty tight timeline, but we can field most if not all of AAS before they begin fielding FVL,” he says. “That gets the scout out there first, performing at the level being sought for FVL.”
Raider will have a 220-kt. cruise in armed configuration. The Army is looking for at least 230 kt. from the JMR demonstrators. Both designs will meet or exceed the Army's 6,000-ft.-alt./95F-day hot-and-high hover performance requirement, which is unmet by any of its existing helicopters.
“There is a way to do that, for AAS to be the lead aircraft before FVL,” says Engebretson. The alternative is for the Army to wait until the FVL Medium-utility and attack fleets are fielded before returning to the AAS requirement with an “FVL Light” design. But that could take decades. “Fielding 3,000 [FVL Medium] aircraft will take a long time,” he says.
Instead of replacing its Bell OH-58D Kiowa Warriors with a new-build AAS, the Army now plans to use available AH-64 Apaches, working with AAIand Gray Eagle unmanned aircraft to perform the armed scout mission. But the larger, heavier AH-64 was not intended for the scout role. “The Apache is not designed for a close, urban fight,” says Engebretson, noting the Raider is within 35 ft. in length and width so it can operate in confined spaces.
Key to Sikorsky's strategy is to use the Raider prototypes to demonstrate the operational advantages of the rigid coaxial-rotor compound configuration to both the armed scout and medium-utility missions. In addition to a 235-kt. maximum speed and 3g maneuver capability, the aircraft retains the conventional helicopter's low-speed agility and adds the ability to perform new maneuvers using the tail-mounted propeller. These include level-attitude acceleration and deceleration and “hanging on the prop” with the nose pointed down for target tracking and engagement.
The two Raider prototypes are being assembled at Sikorsky's development test center in West Palm Beach, Fla., by the same small team that built and flew the company's X2 technology demonstrator. This single-seat aircraft achieved 263 kt. in 2010 and demonstrated the combination of rigid coaxial rotors, integrated propulsion, fly-by-wire control and active vibration control that are at the heart of the Raider and Defiant.
Aurora Flight Sciences delivered the first all-composite fuselage to Sikorsky in November as a single piece, and now systems and equipment are being installed. Next to arrive here will be the tail section, from Aurora.
A transmission systems test rig here will begin ground-testing the engine, rotors, propeller, gearboxes and shafts in mid-year. Roll-out is set for September.
“The Army can't afford an AAS capability at this time. Instead they are looking to the future, at what might be available,” Engebretson says. “With Raider, we will be able to walk in with data on what is available, its performance and affordability. We will have the opportunity, once we have demonstrated the Raider, to move the process along.”