After the publication of information about the first successful flight test of the promising American tiltrotor Bell V-280 "Valor", held in Amarillo (Texas) on December 18, 2017, on the Russian and foreign Internet, one could meet a lot of criticism towards the "tiltrotor" class as such. Of the main technological shortcomings inherent in this type of rotorcraft, the following are indicated: low reliability and maintainability of the nacelle rotation mechanism as a whole (in the case of the MV-22B "Osprey"), or the screw module rotation mechanism with an articulated transmission driven from fixed spiral bevel and angular gearboxes (in the case of the V-280 "Valor"); the enormous complexity of control and the unpredictability of the behavior of machines in the modes of transition to horizontal or vertical flight in difficult meteorological conditions; as well as the presence of the “vortex ring” phenomenon, where, as a result of the twisting of the air flow according to the toroidal principle (along the circle described by the tips of the blades), a critical decrease in the lifting force occurs, which ultimately leads to uncontrollability and the fall of the machine. Among the economic problems, the significant cost of a flight hour of cars is indicated, which, for example, for Osprey is $ 80,000.
Let's start in order. Without a doubt, when comparing Osprey and Valor, one can notice that all-revolving nacelles with Allison T406-AD-400 turboprop engines have some reliability due to the apparent absence of moving transmission units transmitting rotation from the turbine shaft to the propeller. This is indeed the case. Nevertheless, the new design of the fixed power plants of the V-280 "Valor" tiltrotor has incomparably great advantages over the Ellison ones. T64-GE-419 HP engine nacelles (serially produced by General Electric) are in a horizontal position together with spiral bevel and angular gearboxes; only the screw group and the articulated transmission rotate. What does this mean?
Firstly, when the screw module is working on lifting, the most unpretentious and high-strength propeller shaft of the articulated transmission is exposed to the greatest influence of negative environmental factors (dust, sand, etc.), while the gearboxes are covered with a filter and recessed inside the two-module engine nacelles. This allows you to avoid a quick failure of the transmission as a whole (this feature is clearly visible in the photographic material of The Aviationist on August 30, 2017, where the car with registration number N280BH underwent a ground vibration test at the Bell Assembly Center in Amarillo: on the photo with the screw blocks raised shows the absence of the main drive elements in the public domain). Moreover, such a nacelle architecture is less vulnerable during the final phase of a search and rescue operation, or a low-altitude landing of the Marines, when the vehicle is under fire from enemy small arms that can damage the transferred transmission nodes.
Secondly, the horizontal arrangement of the V-280 Valor nacelles has two more indisputable advantages over the Osprey all-revolving engines. First of all, this is a full-fledged viewing area of the side hemispheres around the tiltrotor at the time of being on the surface, as well as the possibility of full-fledged fire resistance in these directions from the shooter's side, covering the landing. But the most important advantage lies in the multiple reduction of the effect of the "vortex ring" effect, which actively appeared on the tip circumference of the MV-22A / B / C "Osprey" tiltrotor blades at the moment when the machines were approaching a vertical landing with a descent rate of about 7 - 8 m /with. It is known that the area of increased pressure under the tiltrotor created on the area swept away by the propellers was also enhanced by the additional reactive thrust from the Allison T406-AD-400 HPT nozzles, which led to an even greater manifestation of the "vortex ring". This happened due to the fact that the thrust vector from the turbine nozzle was deflected with the entire nacelle in the same direction. As a result, the formed "cushion" of increased pressure pushed a fresh air stream to the propeller circumference, after which it twisted into a toroidal vortex and significantly reduced the lifting force of both propellers. In this regard, there has been more than one plane crash of convertiplanes of the Osprey family.
In the V-280 "Valor", even at the moment of the vertical position of the screw modules in the "hover" mode, the nozzles of the T64-GE-419 HPT continue to create a horizontal thrust, due to which the high-pressure cushion under the propeller becomes uneven and the formation of a "vortex ring" does not occur; either happens, but dozens of times less often. This decision can be considered fundamental in the formation of the tiltrotor concept. And it is precisely this that will allow this type of aircraft to emerge, but at a completely different stage, where they will be able to unleash their full technical potential.
As for the comments of observers about the problems with the controllability of converters in various flight modes, including takeoff and landing in difficult meteorological conditions, there is also a lack of awareness. Even the far from newest Ospreys, manufactured by Bell Helicopter and Boeing Rotocraft Systems in the early 2000s, are equipped with a small-sized digital inertial navigation system (INS) LWINS (Lightweighter Internal Navigation System), which, together with the AN / ARN-147 VHF-band computerized navigation receiver (connected to the INS using the MIL-STD-1553B multiplex data bus) and other auxiliary systems, it made it possible to keep the vehicle under control even in incredibly difficult conditions. Moreover, two AN / AYK-14 computers are used at once to quickly process a combat mission.
Consequently, the promising V-280 "Valor" tiltrotor, equipped with an even more advanced inertial navigation system with a more efficient on-board computer, will better cope with the tasks of piloting in the most difficult meteorological conditions and at any time of the day, taking into account various types of terrain. terrain. Moreover, the car will be equipped with a fly-by-wire control system with triple channel redundancy. By analogy with the MV-22B "Osprey", in the aerobatic avionics "Vaylor" it will be possible to find a radar system for low-altitude flight in the mode of following the terrain, which will give the machine a lot of advantages when overcoming the enemy's one-component ground air defense.
Also, some of our commentators can hear the statement that the failure of one of the T64-GE-419 turboprop engines "will cause a complete unbalance of the machine in the air with a loss of control with all the ensuing consequences." However, there is a serious mistake here as well. In line with the MV-22B transmission design, the V-280 "Valor" boasts a synchronized propeller shaft between the two nacelles that passes through relief holes in the fender ribs. This is evidenced by the photographs of the assembled airframe of the test board NB280BH in the assembly shop "Bell Helicopter", taken from the side of the right engine nacelle. In the section of the wing, you can see two holes, one of which can serve to lock the screw module brought into the horizontal (airplane) position, and the second is just intended for installing the synchronization shaft. In the event that one of the engines fails, the second starts to work with increased power, transmitting an equal share of torque to the nacelle angular gearbox with the engine inoperative through the synchronization shaft. Therefore, without additional load, the tiltrotor can safely land on one engine (the main thing is that the gearbox and cardan remain intact).
Let's move on to a review of the tactical and technical capabilities of the new third generation vehicle, as well as the consideration of the V-280 "Valor" as a multifunctional rotorcraft, taking into account the experience gained over the years of operation of the "Osprey" CV-22B (for the US SSO) and MV-22B modifications (for the USMC), as well as helicopters of the UH / MH-60 "Blackhawk" family. To begin with, it is worth noting that the design of the Vaylor fuselage is maximally unified with the fuselage of the Black Hawk family of helicopters (semi-monocoque with a tricycle landing gear, but retractable type). However, unlike the main Blackhawk versions with an all-metal fuselage structure, as well as partial use of fiberglass kevlar dimensions on the cab doors, power plant hood and canopy, the V-280 "Valor" received a one-piece composite fuselage using carbon fiber. This design solves two problems: it significantly reduces the effective scattering surface (EPR), and also reduces the mass of the helicopter, increasing the power-to-weight ratio and flight range of the rotorcraft. As you already understood, the similarity with the Blackhawk cockpit, including the capacity of 14-16 marines / special forces, will allow the USMC and the US Special Operations Force to adapt the vehicle to the experience of the personnel in the shortest possible time.
The reduction of the radar signature of this tiltrotor is also facilitated by a composite tail two-fin V-shaped tail with a camber angle of more than 85 °, which absorbs most of the electromagnetic waves, and part of it reflects into space. The propeller blades for serial samples of "Vaylors" should also be made on the basis of carbon fiber, due to which the expected calculated RCS can only reach 0.7 - 1 sq. m, which is very worthy for this type of aircraft. Thanks to these parameters, the detection range of promising V-280 convertiplanes by surface, ground and airborne radar systems is about 2, 5, or even 3 times less than that of the MV-22B "Osprey". This quality opens up significantly greater horizons for the pilots and the ILC units being transferred in terms of flights and landing in those areas of theaters of operations where the enemy's anti-aircraft component is either partially suppressed (and there are impressive “gaps” in the anti-missile “shield” in the form of unobserved areas of airspace), or the operators of anti-aircraft missile divisions and regiments are immersed in the task of repelling a massive missile strike by hundreds of Tomahawks and JASSM-ERs launched from the boards of strike modifications of Ohio-class submarines, destroyers Arleigh Burke, as well as supersonic strategic bombers B -1B "Lancer".
Even more valuable qualities of the V-280 "Valor" tiltrotor, in comparison with the MV-22B, are the ability to fly around areas with the most dense air defense, as well as to land a MP in the deep rear of the enemy. To implement such abilities in the technological arsenal of "Valor" there are very economical and high-torque engines T64-GE-419 with a capacity of 4750 hp. with a specific consumption of 0.292 kg / kW * h. Despite the fact that their power is only 35% less than that of the T406 (AE 1107C-Liberty), the combat range is 2 - 2, 2 times greater than that of the Osprey (725 km versus 1480 - 1550 km). For example, if the CV-22B "Osprey", having risen from the territory of Romania, are barely able to approach the Black Sea coast of the Krasnodar Territory in a straight line, where they will be quickly detected and identified by Russian A-50U AWACS aircraft at a distance of more than 450 km thanks to their huge radar signature, and then successfully destroyed by the calculations of the S-300V4 air defense missile system even at over-the-horizon range thanks to the use of new 9M82MV missiles with active radar seeker, then when using the V-280 "Valor" you can observe a completely picture.
Considering a hypothetical regional conflict in the Black Sea and Caucasian theater of operations, it is necessary to take into account that using a solid combat radius of 1500 km and low radar signature, the Veilors that took off from the territory of Romania are able to easily reach the required landing point of the MTR in the regions of the North Caucasus that are difficult to view by radar means … To conceal the moment of arrival in the MTR landing zone, the pilots of the V-280 "Valor" can take advantage of the low-altitude flight mode through the mountain ranges in the territory of Georgia, while the main segment of the route will pass in neutral airspace over the southern part of the Black Sea. And most importantly, unlike the Ospreys, the Waylors on this section of the trajectory will absolutely not need refueling by air tankers such as KC-135, KC-10A "Extender" or M330 MRTT, which, due to their huge EPR, will instantly highlight the fact the presence of a threat to our A-50U, which are on alert over the Republic of Crimea and Kuban. This is precisely the main tactical and technical advantage of the large range of the V-280 cover planes over the rotary-wing aircraft currently in service. The speed of this tiltrotor should be limited to 560 km / h, which is no worse than that of the "Osprey".
Based on the characteristics of this tiltrotor, it can be argued that the vehicle is being developed not so much for transporting US Marine Corps units to the theater of operations as for long-distance raids of "green berets" deep into enemy territory, in the vicinity of certain strategically important objects for sabotage and reconnaissance operations., which is also stated by some Western sources. Whether an auxiliary power unit (present in the CV / MV-22B in the center section) is envisaged in the Vaylor's power architecture is still unknown; the specified level of the vehicle survivability in critical situations depends on its presence.
It is worth noting that the developer of the V-280, the Team Valor consortium, sponsored by the US Defense Department, includes not only divisions of American companies such as Bell Helicopter, Lockheed Martin and General Electric, but also a division Israeli concern "Israel Aerospace Industry". It is obvious that Hel Haavir is still interested in high-speed and multifunctional rotary-wing platforms, capable of transferring numerous special forces of the IDF to various hot spots of the Western Asia region. The IDF's interest in the Osprey tiltrotor dates back to 2009, but over the course of nearly a decade, it has faced significant criticism from senior Israeli military officials for opting for the CH-53K King Stallion military transport helicopter. It is likely that this was due precisely to the critically dangerous and unresolved problem of the formation of a "vortex ring". The likelihood of this phenomenon in the V-280 "Valor" is an order of magnitude lower due to the new configuration of the turbine engine with a horizontal thrust of the nozzle and the vertical arrangement of the propeller, and therefore the probability of ordering a new machine from the IDF remains very high.
An interesting detail in the design and refinement of the nacelle design is the reduction of infrared visibility, which the developers strive for. This is not surprising, because most of the air operations of the V-280 "Valor" tiltrotor will take place in conditions of the likely entry into the enemy's MANPADS engagement zone. At the moment, it is difficult to state anything about this, since there is no flat nozzle on the engine nacelle. Nevertheless, you can pay attention to the presence of a 2-nozzle system for removing gases from the HPT T64-GE-419. There are 2 options here: either the developers used an internal second nozzle (on the gearbox compartment) for more efficient circulation of the air flow through the transmission in order to cool it, or they tried to reduce infrared radiation from the jet of exhaust gases from the HPT by mixing with cold air from an adjacent nozzle; but even this point looks extremely unclear, since to reduce infrared radiation, exhaust gases are usually mixed with atmospheric air in a special additional circuit of the engine nacelle, which can be observed in the design of the stealthy strategic cruise missile AGM-129A ACM. At the same time, the above points describe by no means the whole range of possibilities and problems of operating promising Osprey converters as multifunctional platforms.
So, starting in 2014, the headquarters of Bell Helicopter announced the advancement of the design of not only the transport and landing vehicles in the V-280 version, but also the strike version of the AV-280. In this regard, "Vaylors" have a whole host of advantages. The solid volume of the cockpit allows you to place a decent amount of missile and bomb weapons inside, which will not affect the effective reflective surface in any way. Based on the payload mass of 4540 kg, it can be calculated that 4 tactical ultra-long-range cruise missiles AGM-158 JASSM-ER, up to 30 GBU-53 / B SDB-II ("Small Diametr Bomb II"), or up to two dozen promising tactical JAGM missiles with an anti-jamming three-band homing head, represented by an infrared channel, an active millimeter-wave Ka-band radar channel, and a standard semi-active laser guidance channel.
In the case of the JASSM-ER, we get an advanced rotary-wing strike complex, capable of unexpectedly soaring into the air from any part of the theater of operations and striking to a depth of about 2500 km. In the case of JAGM, "Waylor" turns into a vehicle for direct support of troops, which can hover over the battlefield for 3-4 hours, delivering high-precision strikes against enemy armored vehicles from extremely low altitudes and at a distance of 16-20 km. But it should be noted that this is possible only if the enemy has obsolete military air defense systems, for example, the Tungusska-M1 air defense missile system, or the Tor-M1 air defense missile systems and Osa-AKM air defense systems. And even in this case, 100% success from the use of the attack AV-280 is not guaranteed, since the JAGM missiles (like the entire Helfair family) have a low flight speed of 1400 - 1500 km / h, do not maneuver on the trajectory and differ in increased operating time of a dual-mode solid rocket motor. With such features, it is not difficult to intercept the JAGM, especially with the use of television-optical guidance systems that are part of the above complexes. As for the JAGM launch from the AV-280 "Valor", here we see the standard retractable 1x4 modules PU M299, installed on the "Apaches".
Excellent potential is also seen in the anti-submarine version of the V-280, which can be assigned the SV-280 index. If a similar "Osprey" in the SV-22B modification (the possibility of production of which was considered by Bell Helicopter and Boeing Rotorcraft Systems) could provide the US Navy AUG with information about the underwater situation only at a distance of up to 800-900 km, taking into account the range of the tiltrotor and the detection range of submarines by means of active and passive sonar buoys, then similar figures for the SV-280 can reach 1600 km. At the same time, the maintenance and cost of a flight hour for a rotorcraft of the 3rd generation will be about 30-50% less expensive, and it will be much more difficult to find it; feel the difference.
The possibility of equipping the tiltrotor with a refueling bar in the air according to the "hose-cone" principle, as well as the ability to take off and land on unprepared areas of the earth's surface, determines the next strategic advantage of the Vaylor - the ability to deploy tiltrotor squadrons in those parts of the theater where the canvases of the military runways airfields were damaged by cannon and rocket artillery fire, as well as by strategic cruise missiles. From this it follows that in the long term (after 2025), on the basis of the V-280, rotary-wing aircraft systems for radio-technical and optical-electronic reconnaissance, tactical air command posts, repeaters, etc. can be developed.
On the US resource www.militaryfactory.com, you can find a rather interesting review, which, in addition to the already well-known performance characteristics of the V-280, indicates its ability to transfer special forces to the rear zones of a potential enemy: they are expressed in the coverage of the territories of states with the radius of the vehicle. So, the range of the advanced tiltrotor covers 100% of the territory of the DPRK and 90% of the territory of Afghanistan. But for the transfer of special forces to the remote enclaves of the Taliban in Afghanistan and sabotage and reconnaissance activities against Pyongyang, the existing Ospreys with their shorter range, but almost 2 times the number of personnel transferred would be enough. This means that Afghanistan and Korea are just a diversionary maneuver, while the real vision of the US Armed Forces regarding the use of the V-280 "Valor" covers much more serious and extensive theaters of military operations, where Russia and China are present.
