Sikorsky has started building two prototype S-97 Raider high-speed compound helicopters for the US Army's prospective Armed Aerial Scout programme.

The coaxial-rotor, pusher-prop machine is based on the company's revolutionary X-2 design which won the Collier Trophy in 2010. The S-97 is currently in its detailed design phase, but because Sikorsky is developing the aircraft as a prototype, the company has already started fabricating the new rotor-craft.

"We're in detailed design right now," says Doug Shidler, Sikorsky's S-97 programme manager. "And because we're a rapid prototype programme, as we're going through detailed design, we're also building parts."

Parts of the aircraft's fuselage are already being built as are other components throughout the airframe. In fact, some components have already been completed, Shidler says. The objective for the year is to complete the design.

The aircraft should move into final assembly by the middle of next year, Shidler says. The aircraft should enter ground and flight testing in 2014. "Things are moving along as projected," he adds.



Unlike a conventional helicopter, which typically is limited to about 180 knots, the S-97 will be able to cruise at speeds of 220 knots with external weapon and 235 knots clean. It will also be able reach a dash speeds of 245 knots to 250 knots.

The company is committed to building the S-97 regardless of what happens to the AAS programme. The army will make a decision on if it will go ahead with buying a new helicopter to replace the Bell OH-58 Kiowa Warrior or soldier on with the decades-old machine in December. Shidler notes that both the X-2 and the S-97 are entirely funded by industry dollars. The S-97 project is 75% funded by Sikorsky and 25% funded by suppliers-which includes labor and materials.

The X-2 technology is also applicable to the army's Joint-Multi Role (JMR)/Future Vertical Lift (FVL) efforts. The technology can be scaled-up for a medium weight helicopter and to far larger aircraft. Sikorsky has explored concepts that rival the Lockheed Martin C-130 in size-but which has two pusher propellers rather than just one. "You can scale it to whatever you need for a helicopter/rotorcraft mission," says Steven Engebretson, Sikorsky's Armed Aerial Scout programme director.

The service is expected to release a broad area announcement that will examine potential technologies for the future JMR/FVL programme.

"Sikorsky intends to be a competitor in that arena," Engebretson says. The S-97, Engebretson says, is a "great demonstration" of next-generation capability-he notes the X-2 technology will play be key role in Sikorsky's plans going forward.

There are civilian applications for the X-2 technology, Shidler notes, but those are "further off." It could be used for search and rescue or ferrying worker to off-shore oil rigs, for example.

Source: Flight International