rotorcraft of the future in the service of the US Army

Sikorsky-Boeing SB-1 Defiant (FLRAA program)

June saw another achievement by the Sikorsky / Boeing duo in the development of the new high-speed SB-1 Defiant helicopter. It would seem that quite recently (the car performed its very first flight on March 21, 2019), it hovered awkwardly above the ground, showing with all its appearance the experimental nature of the development. However, on June 9 this year, at the Sikorsky flight test center in West Palm Beach, the car accelerated to a speed of 205 knots (380 kilometers per hour), setting an absolute speed record for itself. This is just the beginning of a long and persistent journey and new achievements.

Recall that SB-1 Defiant is part of the FLRAA (Future Long-Range Assault Aircraft) program, generated, in turn, by the Future Vertical Lift (FVL) concept. The latter aims to find replacements for almost all American army helicopters.

Its constituent parts are as follows:

• JMR-Light, or Future Attack Reconnaissance Aircraft. The program is designed to find a replacement for the light OH-58 Kiowa helicopter.
• JMR-Medium-Light (details and current status unknown).
• JMR-Medium or Future Long-Range Assault Aircraft. The program aims to find a replacement for the UH-60 Black Hawk.
• JMR-Heavy. The program aims to find a replacement for the CH-47 Chinook.
• JMR-Ultra. The program is designed to find a car, the capabilities of which would be comparable to the transport aircraft C-130J Super Hercules and Airbus A400M.

The SB-1 Defiant helicopter is one of the main contenders for victory in the Future Vertical Lift. And one of two possible when it comes to FLRAA. According to the requirement of the US Army, the vehicle must carry twelve fully equipped paratroopers with a cruising speed of at least 425 kilometers per hour for a range of at least 420 kilometers.

Defiant is close to meeting the requirements. At the same time, the developers themselves plan that the car will be able to fly at a speed of more than 460 kilometers per hour. The demonstrator is powered by two Honeywell T55 engines and has a recognizable appearance. Like the distant ancestor of the helicopter in the person of the Sikorsky X2, the new device has a coaxial main rotor and a pusher rotor: by the way, Sikorsky used the same scheme for the light S-97 Raider helicopter.

Bell V-280 Valor (FLRAA program)

And although the relationship with tiltrotors from the Americans traditionally does not develop in the best way (aviation enthusiasts are well aware of the technical difficulties and the gigantic price of the V-22 Osprey), Bell is not afraid of technical challenges. Recall that its promising tiltrotor Valor made its first flight on December 18, 2017, that is, two years earlier than its competitor, SB-1 Defiant, took to the skies.

It is not surprising that the aircraft already has a whole series of achievements behind its back. So, on May 16, 2018, the prototype flew in airplane mode: during the tests, the device developed a speed of 350 kilometers per hour. And in January 2019, the tiltrotor accelerated to a cruising speed of 518 kilometers per hour. In December 2019, Valor flew in a fully autonomous mode: the pilots were in the cockpit, but did not interfere with the controls. It is assumed that in the future, such capabilities will minimize the risk to the crew during especially dangerous missions.

Now it is difficult to predict the victory of one or another participant in the competition. Obviously, each of them has its own pros and cons. So, Valor will be able to boast of higher speed, and the choice in favor of SB-1 will reduce technical risks.

Sikorsky Raider-X (FARA program)

The Future Attack Reconnaissance Aircraft (FARA) program, as noted above, is intended to replace the decommissioned OH-58 and supplement the AH-64. It cannot be ruled out that in the future the novelty will generally replace the Apache, but so far the Americans are generally satisfied with their attack helicopter.

The farthest in this direction was Sikorsky, which on May 22, 2015, lifted the Sikorsky S-97 Raider into the sky, built according to a coaxial scheme with a pusher propeller in the tail section. First presented at the autumn exhibition AUSA (Association of the United States Army) 2019 Raider-X is its direct development. In fact, we have a “fat” S-97: the difference in size is about 30%. It is assumed that the device will be able to reach speeds of about 380 kilometers per hour, using the General Electric T901 engine. One of the above images shows the Raider-X, which has a built-in weapon and carries eight air-to-surface missiles on internal holders. The location of the crew members side-by-side makes the aircraft similar to the OH-58, and the shock capabilities bring it closer to Apache.

So far, Raider-X is not in hardware. If Sikorsky does not have serious problems, then the company, under the terms of the competition, will begin testing the prototype at the end of 2022 and, if it wins, will organize mass production of the new machine in 2028.

Bell 360 Invictus (FARA program)

The main challenge for Sikorsky within FARA is not the innovative Raider-X layout and the technical difficulties associated with it, but the direct (and now the only) competitor in the face of the Bell 360 Invictus. It is pertinent to recall that the rest of the competitors (a project from AVX Aircraft and L3 Technologies, a development by Karem and a concept of a combat helicopter from Boeing) dropped out of the competition in March this year.

Invictus is a relatively “conservative” design built around a traditional aerodynamic layout. Also, the vehicle has a tandem arrangement of crew members, which has been proven for combat helicopters: like the Mi-28 or Apache.

Externally, the Bell 360 Invictus helicopter is similar to the long-closed Comanche program, but conceptually there are differences. The main thing is that a promising machine is not an “ultimate” stealth: its unusual appearance is a consequence of the developer’s attempt to ensure maximum flight performance at minimum cost.

And yet, even though the project is based on Bell 525 Relentless technologies, this is a fundamentally new machine. That is, nothing can be ruled out: first of all, that the prototype and even more so the serial version will not differ from the layout previously shown last fall.

It is known that the machine will be able to boast an impressive arsenal: in the images presented, the helicopter carries eight air-to-surface missiles on an external sling and four more on internal holders. We can say that in terms of weapons, it will not be inferior to the RAH-66 Comanche, and possibly the AH-64 Apache.

Of the helicopters presented above, only two will get a start in life: the remaining two are likely to sink into oblivion. Note also that the four vehicles presented above are far from all projects of high-speed helicopters of the future for the US armed forces, but so far we do not know anything about others, except perhaps for a multi-level concept.

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