The Sikorsky S-97 Raider is a high-speed scout and attack compound helicopter based on the Advancing Blade Concept (ABC) with a coaxial rotor system under development by Sikorsky Aircraft. Sikorsky planned to offer it for the United States Army's Armed Aerial Scout program, along with other possible uses. The S-97 made its maiden flight on 22 May 2015. Sikorsky's earliest attempt at a fast compound helicopter with stiff coaxial rotors was the Sikorsky S-69 (XH-59A) flown in the 1970s. Its top speed was over 260 knots but its excessive fuel consumption, vibration and complexity requiring the full-time attention of two pilots led to the program's cancellation. These problems were largely solved on another attempt by the Sikorsky X2 technology demonstrator in 2010. First proposed in response to a Request for Information for the Armed Aerial Scout (AAS) program in March 2010, the S-97 was formally launched on 20 October 2010. It was intended as a contender for a United States Army's requirement to replace the Bell OH-58D Kiowa Warrior. Other military roles are possible, the U.S. Special Operations Command having expressed interest in the S-97 as a replacement for the MH-6 Little Bird, and the possibility of adapting it for civilian applications also exists. Sikorsky plans to build two prototypes of the S-97 as demonstrators. One prototype (P1) will be used for flight testing, while the second (P2) is planned for use as a demonstrator. The first prototype was planned to fly in late 2013 or early 2014. Sikorsky started construction of the two prototypes in October 2012. In September 2013, Sikorsky began final assembly of the first S-97 following delivery of the single-piece, all-composite fuselage by Aurora Flight Sciences. In February 2014, construction of the first S-97 prototype was one-quarter complete. Simulated bird strikes testing had been conducted on the fuselage at speeds of up to 235 kn (435 km/h; 270 mph), the S-97's expected maximum flight speed. Drop tests were also performed to ensure the fuel tanks' safety in the event of a crash. Sikorsky is exploring civil applications for the S-97, such as transporting personnel between offshore oil platforms. Sikorsky and partner Boeing are to use the S-97's technology and design process as a basis to develop the SB-1 Defiant, a high-speed rigid rotor co-axial rotorcraft, for the army's Joint Multi-Role Technology Demonstrator (JMR TD) program. The JMR TD is the precursor to the army's estimated US$100 billion Future Vertical Lift (FVL) program to replace the UH-60 Black Hawk utility helicopter and AH-64 Apache attack helicopter. Sikorsky targeted the S-97 for the AAS program, aiming for the helicopter to fly before the Army downselected. Sikorsky invested $150 million and its 54 suppliers[16] (who provide 90% of the parts) spent the remainder of a total of $200 million on two prototypes; production models aim to meet the program's $15 million unit cost target. However, the Army ended the AAS program in late 2013. Budget projections for FY 2015 included retiring the U.S. Army's OH-58 Kiowa fleet and transferring AH-64 Apache attack helicopters from U.S. Army Reserve and U.S. Army National Guard to the active Army to perform the aerial scout role. Sikorsky suggested the possibility of buying the S-97 to replace lost Apache for armed helicopter needs. Sikorsky proposes S-97 as FVL-CS1; the light scout helicopter. On 5 May 2014, Sikorsky opened the S-97 production hangar during the rollout of the CH-53K King Stallion. At that point, the mostly-composite airframe was almost assembled, including some of the electrical wiring and avionics, missing elements were the transmission, drive train, engine, coaxial rotor, and pusher propeller. The S-97's first military customer is aimed to be the U.S. Special Operations Command to replace the MH-6M Little Bird. Unspecified foreign militaries have shown interest in the S-97; it may be difficult to get approval for export for a next-generation helicopter if the US military does not yet have it. The Raider is a prototype, so the first customer would need to finance a production development program. Its avionics were powered on in June 2014, with rollout on 2 October 2014. For details of design and operational history, click here.
