The next generation of military helicopters will, without a doubt, be a departure from previous generations. There are two major reasons for this: the very notable strengthening of detection and engagement resources against land and naval targets, forcing helicopters operating from these spots to travel longer distances to carry out their missions, and increasing performance. anti-aircraft systems, forcing helicopters to minimize their presence time above engagement zones, and, if necessary, to escape from them as quickly as possible. In other words, speed and range become the key factors in the survivability and performance of a military helicopter of tomorrow.
To respond to these challenges, the US Army launched the Future Vertical Lift program, intended to replace its entire fleet of helicopters, from the OH-58 Kiowa reconnaissance to the heavy transport Chinook. The FVL was initially dedicated to replacing the UH-60 Black Hawk, the maneuvering helicopter supplied to the US Army, and two projects were selected to respond to this: the V-280 from Bell, and the S- 97 Sikorsky Raider. The V280 uses tilt-rotor technology, like the Marine Corps Osprey. The solution has shown its advantages, particularly in terms of speed, but also its risks, with a significant number of accidents during the transition phases. Sykorsy's S97 chose, for its part, a solution with counter-rotating rotors and propulsive propeller, in a mix between Russian productions from Kamov and the AH-56 Cheyenne still born in the early 70s. Unlike the latter, the The anti-torque, that is to say the force which allows the device not to rotate on itself due to the rotation of the main rotor, is provided by the 2 main rotors rotating in opposite directions. The solution certainly provides a high level of performance, but also a very high level of technicality, therefore of maintenance, and therefore of costs.
Although not taking part in the FVL competition because its application was rejected by the US authorities, the Franco-German helicopter manufacturer Airbus Helicopters also studied high speed issues, with the X3 demonstrator equipped with hybrid propulsion using 2 traction propellers distributed on each side of the fuselage, whose energy is captured on the main line, and providing both anti-torque through its applied differential, and increased thrust to reach high speeds. The demonstrator thus reached the speed of 472 km/h at an altitude of 10.000 feet, more than 150 km/h more than the Dauphin from which it was based.
This approach is particularly brilliant, since it is based on a relatively simple technology that does not multiply the moving parts of a helicopter more than necessary, while providing a high level of performance, simplifying maintenance, and reducing the costs of the device. . Airbus Helicopters undertook, in 2017, to develop a new demonstrator based on this technology, the Racer for Rapid Cost-effective Rotorcraft, this time using two propulsion nacelles allowing, according to Airbus, to save up to 10% of fuel, while guaranteeing a cruising speed of more than 200 kts, or 400 km/h.
Surprisingly, the European demonstrator targets first and foremost the off-shore market, a traditional outlet for Airbus Helicopters, and military applications of the technology are, for the moment, not developed. This decision results from the European financing method chosen by the aircraft manufacturer, which only concerns civil equipment. However, the logic which pushes the US Armies to seek greater speed and range of action for their rotary wings also applies to the Europeans, more particularly to France which is implementing 3 projection and amphibious assault ships using, in part, helicopters to deploy forces on land.
It remains to be seen whether the French and European armies will support this remarkable technology, both from an operational and commercial point of view. Very often in France, and more generally in Europe, the time spent between the idea and the application of the idea causes a large part of the relevance and exclusive advantages of the idea to be lost.