The American helicopter manufacturer Sikorsky has just unveiled the first prototype of its S-97 Raider army reconnaissance helicopter. A first flight is now expected before the end of the year. The device sharply contrasts with existing helicopters demonstrating an innovative propulsion system: the coaxial rotors are backed by a pusher propeller allowing pushing the giant suppository to a faster cruising speed than 400 km / h. Without sacrificing any of the inherent workability specific to this helicopter, the S-97 promises a speed equal to the one of a light aircraft.

The prototype displays a very profiled fuselage, a cockpit for two pilots placed side by side and a minimal cargo compartment, enabling six soldiers to board the aircraft, ammunitions or additional fuel. If we had to sum up, we could see in the S-97 a hybrid between the Russian Mi-24 and its small cargo compartment, and the AH-56 “Cheyenne” abandoned in 1972 because of its exorbitant cost, but had already the idea of a pusher propeller to go faster.

The S-97 is based on research conducted with the X-2 demonstrator, which reached a speed of 460 km / h in level flight in 23 flight tests. But will the success of the X-2, which owed a lot to the lightness of the machine (only 2.5 tones) and its over-motorisation, be reproducible with a machine of more than 5 tons? Another key question, will the extremely compact coaxial rotors, with blades close together, allow holding factors of high loads with no risks that the two rotors touch each other?

Last but not least, will the US Army Aviation let itself be tempted by this helicopter? The AAS program (Armed Aerial Scout) that aims at replacing the OH-58D and to which the S-97 is designed to meet, was put in the refrigerator last year by the US army.