At the end of 2012, a well-known American helicopter manufacturer, Sikorsky, began assembling 2 prototypes of the high-speed combined reconnaissance helicopter, also called a rotary wing, S-97 Raider. The development of this rotorcraft is in the interests of the American army. According to representatives of the manufacturer's company, the assembly of the first two prototypes of the S-97 Raider is planned to be completed in mid-2013, and the first tests of the new vehicles will begin in 2014.
The S-97 Raider is based on the company's high-speed prototype X2. This model, in addition to the coaxial main rotor, is equipped with a pushing tail rotor and wings of a small area to create lift. According to the project developers, their brainchild is able to reach speeds of more than 460 km / h. In service with the American army, the new S-97 Raider helicopter can replace the outdated Bell OH-58 Kiowa Warrior reconnaissance helicopters, which were in service with the US army during the Vietnam War.
The company sent its proposals for the promising Sikorsky S-97 Raider helicopter, based on the Sikorsky X2 concept, to the command of the US Army in March 2010. The Raider, like the helicopter demonstrator, has the same layout. At the same time, in the combat version of the helicopter, a cockpit for 6 paratroopers (scouts) will be located immediately on the pilot's cockpit for 2 crew members in the airborne assault version, and in the reconnaissance and assault version there will be a special weapons compartment and an additional fuel tank. It is worth noting that American designers practically followed the path of creating the concept of a "flying infantry fighting vehicle", taking into account the very high modern requirements for maneuverability and speed of the vehicle.
According to the developers of this project, the implementation in practice in a new light reconnaissance-attack or airborne assault helicopter of all those developments that were once obtained during the tests of the X2 technology demonstrator that lasted for 2 years, will significantly improve flight characteristics cars. According to them, the combat version of this device will satisfy or surpass all the requirements that are imposed on it by the command of the US Ground Forces. According to the director of the program for the development of a new combat vehicle Dag Shidler, the Sikorsky S-97 Raider helicopter will allow the US Army to successfully carry out combat operations in the highlands, where today no combat helicopter in the world is able to operate with the same efficiency.
It should be especially noted that during the tests of the X2 prototype, its design underwent a number of changes. In particular, the configuration of the tail unit of the machine was changed: the designers mounted 2 additional stabilizers on the lower keel, having a total area of 0, 46 sq. meters (before that, to increase the directional stability of the helicopter, each of the end plates of the main horizontal tail of the helicopter was increased by 0.28 square meters). A solution to increase the area of the main stabilizer could be considered ideal, but such a change would lead to a serious alteration of the entire structure and a longer investment of time. In addition, aircraft designers have improved the vehicle control system. According to the creators, all this made it possible to reduce the load on the helicopter pilot and make the controllability of the machine more reliable, especially during high-speed flights.
When certain persons related to the Russian Ministry of Defense wanted to "criticize" the combat effectiveness of domestic coaxial helicopters, created in the Design Bureau named after. Kamov (for example, the well-known Ka-50 helicopter), their main argument, in addition to the fact that “a two-deck helicopter cannot be a combat helicopter,” was that nowhere in the west are pine-pattern helicopters used in this capacity. However, now this situation seems to be coming to an end and this argument may soon lose its relevance. When in the 1990s in the West, referring to the Soviet experience in creating the Ka-50 helicopter, the second wave of coaxial helicopter research began, this was not yet accepted by everyone. But after Sikorsky Aircraft developed the X2 coaxial demonstrator program, the veil fell from the eyes of almost all interested parties. Already in the near future, co-axes, albeit not quite in the form of helicopters, may appear in service with the American army.
In any case, movement in this direction seems more than obvious, and given the ability of the United States to finance any promising developments, one can be sure that the project will be brought to its logical conclusion. On January 13, 2013, Sikorsky Aircraft and Boeing entered into an agreement in response to a request from the Office of Aviation Applied Technologies to develop a Joint Army Multipurpose Technology Demonstrator. The multipurpose rotorcraft, already known as the S-97, will be based on the X2 rotorcraft, according to both well-known companies.
It should be admitted that this piece of engineering thought looks somewhat unusual. The S-97 is equipped with two coaxial screws located close to each other, but it moves forward not with their help, but with the help of the rear pushing screw. As a result, it is possible to eliminate the excessive complexity of the coaxial helicopter design - at the cost of developing a separate mechanism that is responsible for the horizontal movement of the machine. It is reported that the experimental car was able to reach a speed of 486 km / h, but for the developments of the Sikorsky company this is not a record. The S-69 helicopter managed to achieve similar speeds back in the 70s of the last century.
However, now we are talking about a rotorcraft, and not about an ordinary helicopter. Today, all normal helicopter layouts have fundamental limitations that prevent an increase in flight speed. It is known that the efficiency of the main rotor is, by definition, lower than that of a fixed aircraft wing. It is for this reason that classic helicopters will never see those flight speeds that are available to modern aircraft, nor can they maintain a high cruising speed. The main rotor, which creates not only lift, but also thrust for forward motion, as well as losses for countering the reactive moment - all these design solutions are effective only when taking off and landing from a patch, but not for a fast forward flight. So today, after receiving an order for a combat flight, the reaction speed of the attack link of helicopters is equal to the speed of the same link of Ju-87 attack aircraft, which were used by the Germans 70 years ago.
It is for this reason that aircraft designers from the Sikorsky company, starting from the technical appearance of the S-69B and the X2 prototype, used in the new model a narrowed streamlined fuselage, a coaxial main rotor and a pushing propeller in the rear of the machine. The main rotor diameter is just over 10 meters, the maximum take-off weight is just over 5,000 kg. It can be noted that at first glance this is not so much for a two-seater combat helicopter.
Although the Sikorsky S-97 Raider is now called a multipurpose vehicle that will most often be used as an armed reconnaissance, some experts believe that in this case it is more about disguising true intentions in case the project suffers some setbacks or technical difficulties appear. … The US Army currently has a large number of UAVs that are cheaper than the alleged X2 rotorcraft. Therefore, reconnaissance helicopters based on it for the American military are not the most necessary thing, while the interest of the army special forces in the new product is quite understandable. This machine is ideal for transferring a small reconnaissance and sabotage group to the shallow rear of the enemy, while, if necessary, the helicopter will be able to provide air support to the paratroopers.
The impact potential of the novelty should not be underestimated: due to the relatively simple piloting (the movement of the rotorcraft forward is not due to the use of rotors), this device is promised to be made capable of unmanned flights with remote control from the ground. In this version, without landing on board, the rotorcraft will be able to carry more than a decent combat load. However, for now, all the armament of the aircraft is reduced to a fleet of unguided rockets or ATGM Hellfire, as well as a movable turret with a 12.7 mm M2HB machine gun (500 rounds of ammunition). At the same time, the main player on the battlefield of the S-97 Raider will never become, since he does not have a corresponding reservation. The trend is made specifically for speed with a combination of some percussive capabilities.
Representatives of Sikorsky's company promise that the S-97 Raider will be able to develop a cruising speed of about 426 km / h, and the maximum flight range can be 1300 km. Both the indicator for such a machine looks more than solid and radically surpasses the performance of all modern combat helicopters in the world.
Although the aircraft, due to the transportation of up to 6 paratroopers, in fact becomes multipurpose, some questions still arise. In particular, concerning the vulnerability of the rotorcraft. It can be higher than that of functional analogs, due to the greater number of screws and the relatively close arrangement of the bearing coaxial screws, which can lead to their overlap. These circumstances can only be clarified by the actual use of the new vehicle in combat conditions.
One way or another, there is still time before the tests, which should begin in 2014, and it is still difficult to say something concrete about the fate of this project. At the same time, such a machine in the American army has a free niche that it can occupy. The world's only mass-produced V-22 tiltrotor is too bulky and heavy for some tasks that require vertical takeoff and landing in combination with high speed, and classic helicopters are slow enough for them.
