tiltrotor

The very first detailed tiltrotor project was the Wesserflug P.1003, developed in Germany in 1938 by designers Rohrbach and Simon. According to the project, it was supposed to create a two-wing tiltrotor with a rotary wing (more precisely, only the ends of the wing should have rotated, with a fixed middle). However, due to the war that began the following year, the project was never implemented. The second detailed tiltrotor project in the same Germany was not implemented due to the end of the war. Since the firms Focke and Ahgelis intended to build their Fa-269 as a wunderwaffe. According to this project, the tiltrotor was supposed to have “pushing (rather than pulling, as in classic tiltrotor projects) three-bladed propellers, which, thanks to a very high landing gear, could turn down during takeoff. Curiously, there was supposed to be only one (but very powerful) engine, which was supposed to be located in the fuselage, and inside each wing there had to be a transmission leading to a rotary screw.

Other unrealized projects of the Wunderwaffe with helicopter takeoff from Heinkel - Wespe and Lerche did not have any rotary propellers or rotary wings, but had to take off and land like a helicopter due to the vertical position of the fuselage during takeoff. Both projects differed only in weight and dimensions, and had a similar design from a hull cut in half in the middle of which there should have been a pair of screws enclosed inside one annular wing. With a vertical fuselage, it was supposed to take off and land, as well as the extremely original unrealized project of the wunderwaffe - Tribfluegel from Focke-Wulf, which has a rotating Y-shaped wing, which is also a three-blade propeller rotating not from a piston, but ... a jet engine, like a Bengal wheel. Curiously, Heinkel had a similar wunderwaffe project - Ypsilon, which differed from the Focke-Wulf Tribfluegel only in that its wing did not rotate (that is, unlike the Focke-Wulf - it should not have been a rotorcraft, in the literal sense of the word, but just a jet aircraft with vertical takeoff).

Tiltrotor with turning screws

A convertoplane with rotary propellers (tiltrotor, (tiltrotor) is an aircraft that combines vertical takeoff / landing according to the helicopter principle with movement at the speed of a turboprop aircraft.

Usually, not the propellers themselves are rotary, but nacelles with propellers and engines (like the Bell V-22 Osprey), but there are also designs in which only the propellers rotate, and the engines (for example, located in the fuselage) remain stationary. An example of a rotorcraft where only the propellers turn is the Bell XV-3.

It should be noted that the term tiltrotor is not equivalent to a tiltrotor, since it is a specific implementation scheme for a tiltrotor.

tilt-wing tiltrotor

Tiltwing X-18 turns wing

Four-engine experimental tiltwing XC-142A

There is a variant of a tiltrotor called a tiltrotor with a rotary wing (tiltwing; Tiltwing, from tilt - turn and wing - wing), when the entire wing rotates, and not just the tips, like a tiltrotor.

The disadvantage of the rotary wing is its great complexity, the advantage is that during vertical takeoff the wings do not obscure the airflow from the propellers (thus increasing the efficiency of the propellers).

Tiltrotor with propellers in annular channels

Aircraft with vertical takeoff (or short take-off and landing) with propellers in the annular channels can be referred to as having rotary propellers or having a rotary wing.

Their peculiarity is that the screws are located inside a special ring, which is sometimes called an “annular” wing, in aircraft modeling such a screw in an annular channel is often called the term “fan” propeller (in aircraft modeling such a screw is usually hidden inside a jet engine model) . This type of propeller has a very high speed of the air flow thrown off by the propeller, which makes it possible to get by with very small wings, providing a high compactness of the tiltrotor. The same advantage turns into a serious drawback when performing the functions of a helicopter, as a result of which funding for the development of such convertiplanes was stopped as soon as it came to their ability to completely replace the helicopter.

Examples of such convertiplanes are the Bell X-22 A, Doak VZ-4DA and Nord 500.

VTOL with vertical position

A vertical takeoff and landing aircraft with a vertical body position (tailsitter, tailsitter (), from tail - tail and sitter - sitting) - a variant of the VTOL layout. Such an aircraft takes off and lands on its own tail like a helicopter takes off and lands, and then goes into horizontal "aircraft" flight. Despite the impossibility of landing “on an airplane”, it is not a tiltrotor, since when switching to a horizontal flight mode, the propellers do not turn relative to the wing and fuselage of the aircraft. The complexity of the scheme lies in the organization of control in the modes of vertical and horizontal flights, as well as transitional ones - it is difficult for the pilot to navigate, because the same controls perform different functions in different modes, in addition, visibility is difficult in vertical modes. Nevertheless, the absence of large turning parts, as well as a single power plant for vertical and horizontal flight modes, made it possible to simplify the design of the device, and this scheme was popular with designers for a long time. This scheme was used by both jet and screw VTOL aircraft. A few VTOL aircraft built according to this scheme remained experimental prototypes.

In 1972, at the Mil Design Bureau, a project of the Mi-30 propeller plane arose, which has a classic scheme with a pair of rotary propellers (nacelles with propellers and engines). Within the framework of this project, analytical and design studies were carried out, which consisted of both theoretical work and tests of models of the rotary screw on an aerodynamic stand. Based on the results of these works, relevant studies were introduced into the rotorcraft project, for example, the take-off weight increased from 10.6 to 30 tons, with a simultaneous increase in both engine power and payload. The construction of the first flying models was planned for 1986-1995, however, due to the onset of restructuring, the rotorcraft was not built.

Notes

Links

• American engineers are developing a heavy tiltrotor. // "Membrane"
• Tested unmanned reconnaissance tiltrotor. // "Membrane"
• Vladimir Spitsyn. What is a tiltrotor? // "City of Vorkuta"

see also

• Bell V-22 Osprey - the only tiltrotor in service
• Nord 500 (en:Aérospatiale N 500) is a very compact tiltrotor with a futuristic look

VTOL aircraft with jet engines in rotary nacelles

• Boelkow-Heinkel-Messerschmidt EWR VJ 101
• Bell D-188A

tiltrotor - This is a twin-rotor aircraft that combines the advantages of a helicopter and an airplane at the same time. On such an apparatus, both propellers are located on the wings of the apparatus. For vertical takeoff or landing, the propellers are parallel to the ground. After lifting to the required height, the screws turn through an angle of approximately 90 degrees and become pulling screws.

The evolution of these devices began with autogyros. The first gyroplane was the British Fairey Rotodyne (1950), manufactured by the Fairy company (here is such a play on words - the gyroplane was created by the Fairey company). It is mistakenly called a rotorcraft. However, the world's first classic rotorcraft, we can safely consider the development Kamov- KA-22 (1960). By the way, according to Wikipedia, only one sample survived KA-22 And if someone knows where he is now, please share the information. Already in the early 60s, KA-22 removed from mass production after a series of disasters. Further in the USSR, they did not even intend to return to devices of this class.

However, US leaders had a different opinion and continued to develop the direction of rotorcraft, allowing the screws to change the thrust angle, thereby creating a new type of aircraft - tiltrotor. In 1989, the first tiltrotor was tested, on which the best US developers worked 30 years. So the Bell V-22 Osprey saw the light. But he was not appreciated. Already in the early 90s, it was decided to give this toy to the Marines. At V-22(as with all tiltrotor developments) I see one drawback - the loss of traction due to the resistance of the wings, which are under the propellers. A short discussion of helicopter pilots in the forum suggests that V-22 really good.

I think that it is with the advent of information about V-22, as a new type of aircraft, we also took up the development of an analogue. Already in 1972, the specialists of the Moscow Helicopters named after. M.L.Milya, began the development of a tiltrotor Mi-30. The first flight of this device was supposed in 1991. More about development Mi-30 read . But due to the difficult economic situation in the country, Mi-30 and remained on paper.

Here I also want to note that the world's fastest helicopter for 2008 (performed by the way rather like autogyro) does not reach and 500 km/h. A V-22 already since 1990 reaches its maximum speed 638 km/h. In addition, it accommodates 24 paratroopers.

The fact that VA-22, which turned out with excellent technical characteristics, was rejected without argument to the Marine Corps, and even in a "reduced edition", as well as a not very clear incompleteness of development Mi-30, tells me that most likely this type of apparatus (tiltiplanes) is still being developed, but not advertised.

AND NOW THE MOST IMPORTANT! In the movie "Avatar", in my opinion, demonstrated almost perfect aircraft, made on the principle of a tiltrotor. In all reviews of the film, it is so, correctly called - a tiltrotor.

The screws of this machine can rotate in almost any direction, not even in sync which allows him to be super-maneuverable. It has the ability to develop huge speeds or stand still in the air, even in strong winds, compensating for wind correction with the help of an optimal angle of rotation of the propellers. The presence of safety rings allows you to protect the screws from breakage during maneuvers in extreme conditions. This ideal general purpose aircraft. It is not necessary to talk about the military sphere here.

Such aircraft would become indispensable assistants in the service of the police, ambulance, and rescue services. I also foresee the emergence of a new sport - convertoplanning. Convertiplane races would gather crowds of spectators around the world, where the main competitive moment was used not only the speed of this device, but also its super-maneuverability.

Of course, in the future, to improve performance, convertiplanes will use rocket launchers instead of propellers. A propeller is just an example of a source of thrust for a tiltrotor. The photo next to it is just an example of a jet tiltrotor.

I am not a mega-specialist in the aviation technical environment and was guided in this article mainly by logic, so I will be glad if my assumptions about the future of convertiplanes are corrected by a competent specialist.

On the video, the trailer for the game "Avatar". Watch only the first minutes of the video, which demonstrates the player's flight on a tiltrotor. Just pay attention to how maneuverable this thing would be in reality.

The modern aviation industry produces a huge number of very different aircraft, which differ not only in size, but also in design features, as well as purpose. We are all used to the fact that there are two main, most popular types of aircraft: airplanes and helicopters. But few people remember that there is another type that combines the previous two, and it's called tiltrotor. What kind of miracle of technology is this, we will look at the example of real samples.

Creation of the first prototypes

Even before the outbreak of World War II, several countries, including the USSR and Germany, took up the development of a new type of aircraft. As planned, the design should have had rotors that controlled vertical movement, as well as main traction engines.

Ideally, of course, such a tiltrotor should have had a rotary motor that changes its position depending on the direction of movement.

The very first samples were a rocket aircraft, which was set at an angle of 90 degrees to climb on the launch pad. Taking off, the car flew already "like an airplane."

The Germans went a little further. They made a model in which it was possible to change the geometry and angle of the wing. It should be clarified that most of the developments remained only on paper, since the outbreak of war prevented their implementation.

Osprey: American tiltrotor

In the mid-80s of the 20th century, the development and flight tests of the first serial aircraft with rotating traction engines were being actively completed in the United States. The car was named Bell V-22 Osprey. However, their mass production began only in 2005.

As for the design, the device is equipped with two powerful motors. The creators placed them in special gondolas at the ends of the wing. They can rotate up to 90 degrees.

To increase the level of mobility and the ability to deliver the vehicle by large transport aircraft, as well as to enable it to be based on the deck of aircraft carriers, mechanisms have been developed that fold propellers and wings.

A distinctive feature of the Osprey from other representatives of the air fleet is the hull and frame, made on the basis of fiberglass and composite alloys, which makes the tiltrotor itself unusually light.

Being in service with the US Marine Corps, the Bell V-22 Osprey has several advantages over conventional helicopters and aircraft:

• Sufficiently large load capacity of 5445 kg;
• The ability to quickly deploy the device in a combat position;
• The cargo compartment can accommodate 24 people or 12 lying wounded;
• Special hooks allow you to transport bulky goods;
• Vertical landing and high cruising speed make it possible to quickly deliver and evacuate paratroopers and weapons from the battlefield.

The US military uses this type during local military conflicts. Such a machine can not only be used as an amphibious vehicle, but also as fire support for troops.

Convertiplane Russia VRT30

Unlike the United States in Russia, the development of this kind of technology and have not been fully implemented. In the Soviet Union, in the late 1970s, the development of the Mi-30 tiltrotor was carried out, which over time was supposed to replace the well-known Mi-8 helicopter. However, due to the collapse of the USSR, the project was never completed.

The only company that can organize and establish the creation of prototypes, and then mass production, is the Russian Helicopters holding. We are talking about a promising unmanned propeller plane VRT30, which, in addition to the function of a reconnaissance aircraft, could perform other tasks.

As for the current state of affairs, the only potential customer for these aircraft is the Russian army. Given the global trend in the development of high-precision technologies, most likely, designers based on flight tests of the VRT30 will be able to create a small-sized propeller-wing aircraft, both military and civilian.

Electric tiltrotor

The German corporation Lilium Aviation has already announced the successful flight of the Lilium Jet rotorcraft powered entirely by an electric power source. Experts predict the success of such a startup. As for its technical nuances, the following can be distinguished:

1. The capacity of the car is 2 people;
2. 36 electric motors installed on special block mounts;
3. Engine power 435 hp;
4. The maximum cruising speed is 300 km/h;
5. The maximum takeoff weight is 600 kg;
6. Load capacity 200 kg;
7. The flight range from one battery charging cycle is up to 300 km.

From a safety point of view, each of the motors in the Jet is equipped with its own power supply system. In the event of failure of several engines, the pilot will be able to make an emergency landing without fear of losing control.

The on-board computer fully controls the entire flight cycle, and in the event of any dangerous maneuvers, the system will automatically take control.

Lilium Aviation plans in the future to launch the production of such machines, which will be able not only to replace the usual helicopters, but also to become a daily means of transportation.

Rotorcraft of the future

Scientific and technological progress does not stand still and every day something new and unusual appears in the world. This also applies to the creation of aircraft units.

Developments to bring new ideas to life are carried out around the world. Many companies specializing in the production of electronics and automation decided to make attempts to build convertiplanes. Modern prototypes are characterized by relatively small dimensions, as well as the use of lightweight materials in the manufacture.

Scientists suggest that in addition to cars in cities, it will be possible to see such transport as a tiltrotor. What kind of car this is, many people have so far only heard or seen in pictures, but in the near future this type of technology may become indispensable for our lives.

Video about rotorcraft

In this video, engineer Igor Avdeev will tell you what aircraft, in addition to convertiplanes, mankind has invented:

AND A product of the American aircraft manufacturers Boeing and Bell Helicopter, the V-22 Osprey is the first serial military aircraft with a tipping rotor (tiltrotor). The Osprey or Osprey (Osprey) has the ability to take off and land vertically, and to take off or land using a short taxiway. The purpose of the development of the device was to combine the capabilities of a high-speed helicopter and a long-range turboprop aircraft.

Historical retrospective and current position of the V-22 Osprey

The United States military made an unsuccessful attempt in 1980 to free American hostages in Iran. The operation showed that the helicopters involved in it did not correspond to the tasks of the mission. This led to the need for an aircraft capable of not only taking off and landing vertically, but also flying faster, higher and farther than a conventional helicopter.

The response to these requirements was the project "Experimental vertical takeoff and landing aircraft" initiated in 1981 by the US Department of Defense ( Joint-service Vertical Take-off/Landing Experimental Aircraft, JVX). As a result, everything ended with the development of two variants of the Osprey tiltrotor: MV-22 for the Navy and Marine Corps and CV-22 for the US Air Force.

In general, about 29 years passed from the start of the JVX project to the receipt of the first samples of the CV-22 Osprey by the troops. Obviously, the V-22 "Osprey" was not an exception to the rule, but only confirms the well-known postulate. The implementation of projects in the field of modern complex military aircraft requires decades of work. The expanded implementation of the V-22 Osprey program led to the fact that already at the introductory stage of the project it became necessary to carry out the first measures to eliminate obsolescence.

According to experts, the 15 years between the first flight and the decision to start mass production were also not easy for the formation of a tiltrotor. On the one hand, at this time, the developers faced special technical challenges and temporary setbacks associated with them. On the other hand, the V-22 Osprey had to overcome significant political resistance, including from the leadership of the US Department of Defense.

Economic aspect

According to media publications, the economic success of the program has not yet been definitively assessed. First of all, not all V-22 Ospreys under construction have been delivered to customers. In addition, there are still prospects for additional export contracts.

By the start of mass production in 2005, the US military planned to purchase a total of 458 V-22 Osprey vehicles in various versions. In the process of changes in the defense budget, this number has decreased. As of 2013, about half of the original plan still remains. At the end of 2014, more than 200 convertiplanes were delivered.

So far, Japan remains the only export buyer. In 2014, the Ministry of Defense of this country decided to acquire 17 V-22s. The Japanese Parliament in 2015 approved appropriations for the purchase of an initial five vehicles. The first tiltrotor was handed over to the customer in August 2017.

India and South Korea are also showing interest in the V-22. Negotiations with both states are reported. However, neither the discussed amount of equipment, nor the prospects for concluding contracts are reported. The situation developed similarly with Israel and the United Arab Emirates. Moreover, in the case of Israel, the negotiations have made sufficient progress. However, in the end, both countries settled on the use of conventional helicopters.

Convertiplane modernization

Bell and Boeing are currently actively integrating new features into their product, thereby trying to maintain increased interest in the V-22 Osprey among national buyers.

So, the manufacturer managed to prove the suitability of the V-22 for the transportation of engines of the F-35 aircraft. This increased the interest of the US Navy and the US Marine Corps (and possibly Britain) in using the V-22 Osprey as part of the transfer from shore to board an aircraft carrier ( Carrier Onboard Delivery, COD).

The manufacturer, on its own initiative, developed an in-flight refueling technology using the V-22 Osprey. The innovation should allow the US Marine Corps to carry out refueling in the air, using their landing craft as a base. This will greatly enhance the combat capabilities of the F-35B Marine Corps. The prospects that open up are like access to aircraft carrier resources or ground-based aerial refueling facilities.

Other current program activities are focused on improving the logistical availability of the V-22 Osprey. In particular, in 2015, construction began on the so-called V-22 Osprey Operational Readiness Center ( Readiness Operations Center). The center should improve the efficiency of the fleet of these machines by combining technical and logistical indicators. The organization is similar to a similar automated logistics information system ( Automatic Logistics Information System, ALIS) for the F-35 aircraft.

Specifications and weapons V-22 Osprey

The V-22 Osprey has one rotary turboprop engine with a transfer mechanism and a rotor (propeller) at the end of each wing. For takeoff and landing, the engine is installed vertically, and the rotors are horizontal, like a helicopter (helicopter mode).

When transitioning to en-route flight, both engines tilt forward 90 degrees for 12 seconds. As a result, the V-22 Osprey becomes a twin-engine turboprop aircraft (airplane flight mode). On average, the V-22 spends more than 75% of its flight time in airplane mode. For short taxiway takeoffs and landings, the actuators tilt forward at an angle of about 45 degrees.

Two Rolls-Royce AE 1107C engines are installed on the machine. It is noted that efforts to integrate an alternative type of engine have not yet yielded results. Through the connecting shaft and the transmission mechanism associated with it, in the event of a malfunction of one of the engines, the other is able to rotate both screws. However, in this state the V-22 Osprey cannot hover. The failure of one of the two turboprops results in both shutting down and an emergency landing, as the propellers cannot rise upwind.

In addition, the customer's requirement to minimize the space occupied by the V-22 on board the ship was fulfilled. Its wings, engines and propellers in the folded state are located along the longitudinal axis of the aircraft. The complex mechanics of the engines and the possibility of transformation were the most difficult technical challenges that had to be overcome during the development of the V-22 "Osprey".

The V-22 has state-of-the-art glazing and cockpit controls, as well as extensive navigation and communications equipment. In particular, the autopilot allows you to transfer the flight along the route to the position of hovering at a height of 15 m. At the same time, external programming of the system by the crew is not required.

Control is via a triple redundant fly-by-wire flight control system ( Fly-by-Wire-System). The system is considered sufficient for general mechanical adjustment of the blades in helicopter mode. In airplane mode, the V-22 Osprey is controlled using flaperons, rudders, and elevators.

The fuselage of the car is not airtight. This means that crew and passengers at altitudes above 10,000 feet (more than 3,000 meters) must wear oxygen masks.

Armament V-22 Osprey

Initially, a machine gun (7.65 or 12.5 mm) mounted on the aft ramp was provided as the only armament of the aircraft. This decision has been criticized. After that, part of the MV-22 received a temporary defensive weapon system ( Interim Defense Weapon System, IDWS) developed by BAE Systems.

This remotely controlled weapons system consists of a rotating turret with automatic weapons placed under the fuselage, one TV / IR sensor and a control station inside the aircraft. In particular, since 2009, the system has been received for the MV-22 used in Afghanistan. However, it limited the possible payload to 360 kg and could not be used according to all requirements. As a result, they refused to use it.

According to publications, since 2014, the possibility of equipping the tiltrotor with new offensive weapons has been considered. This is not about creating another offensive air platform, but about increasing the suitability for conducting operations in support of special forces (SpN).

Considerations are primarily aimed at high-precision air-to-ground weapons. For example, AGM-114 Hellfire missiles, AGM-176 Griffin missiles, a single air-to-ground missile or light glide bombs (for example, GBU-53 B SDBII). The integration of this kind of weapon requires the installation of two pylons under the front of the fuselage and the installation of a laser target illumination system (L-3 Wescam MX-15). Already in November 2014, Bell and Boeing, at their own expense, conducted the first tests on the integration of such weapons.

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Combat capabilities

Like medium and heavy transport helicopters, the V-22 Osprey also contributes to the following tasks of tactical air transport:

• logistics air transport (deployment and provision of forces);
• air mobility of ground forces;
• air transport of the wounded ( MedEvac);
• rescue and return of personnel (recovery of personnel, Personnel Recovery, PR), including search and rescue in a combat situation ( Combat Search and Rescue, CSAR);
• military evacuation operations MilEvacOp);
• tactical support for Special Forces forces ( SOF Air).

According to experts, the requirements: to fly faster, higher and farther than a helicopter - the V-22 Osprey performs without question. Its maximum and cruising speeds (about 180 km / h, 100 knots) are higher than the corresponding values ​​​​for heavier helicopters: the CH-47F or CH-53K models from Boeing and Sikorsky, respectively. The service ceiling is slightly above 6,000 m (20,000 ft).

Since the V-22 Osprey operates in aircraft mode on the route, the flight range without aerial refueling or internal additional tanks reaches 1,627 km for the MV-22 Osprey. This is much higher than the capabilities of helicopters. A similar parameter of a helicopter with an extended range CH-47F ER ( ExtendedRange) reaches 998 km. When refueling in the air, the tiltrotor during exercises and during operations demonstrated the ability to overcome distances for which no helicopter would be used. Firstly, because of the significantly greater time requirement due to the lower flight speed. Secondly, for technical and logistical reasons.

Taking into account the largest payload (9070 kg in the cargo hold and 6800 kg on the external sling), the V-22 Osprey is considered by Western military and technical specialists as an improvement on a series of helicopters previously used in a similar range of tasks. However, their use is not advisable due to peak load values. In this case, CH-53K is given as the standard. Similar estimates apply to the volume of the cargo compartment of the tiltrotor.

In terms of speed, range and payload, the V-22 Osprey is considered by experts to be particularly suitable for tactical support of Special Forces forces, evacuation operations, personnel recovery, CSAR and MedEvac. Its payload is basically sufficient to carry the necessary personnel and materiel for infantry operations.

The range of the V-22 guarantees access to remote combat areas, enabling rapid grouping of forces stationed at widely spaced starting points. Its speed maintains surprise and initiative, and enhances the possibility of sustained autonomous action. The tiltrotor "compresses" the time and space of operations and allows you to complete critical processes on time (for example, using the so-called "golden hour" in air medical evacuation operations).

Critical points

According to experts, the V-22 Osprey program has been regularly subjected to intense criticism and rejection throughout its development.

In 1989-1992, US Secretary of Defense Dick CHENEY and the US Congress argued over funding for a project that the Secretary of Defense considered expendable. Again and again there are doubts about the efficiency, reliability and safety of flights. Time Magazine in October 2007 denounced the V-22 Osprey as "unsafe, overpriced and totally inadequate".

In 2015, Israel and the United Arab Emirates, despite initial interest, abandoned purchases of the V-22 Osprey. Obviously, they came to the conclusion that conventional helicopters are a more suitable solution for their operational purposes.

According to independent sources, it is difficult to judge how justified the claims are in detail only from open data. Because both critics and proponents of the V-22 in the US Army, industry, politics and the media make statements that are extremely rare to present clear factual arguments. (Not least, this is because much of the information is classified as a military secret or industrial intellectual property.) The figures are given without a calculation basis, which makes comparisons inaccurate or impossible.

Below are estimates of the two most frequently criticized aspects of the tiltrotor program.

V-22 Osprey cost

The purchase price of the product in the kit ( flyaway cost) for one V-22 Osprey in fiscal year 2015 was $72.1 million. For comparable conventional helicopters, this figure is about half that amount ($35 million to $40 million).

However, the United States Accounts Office (GAO) at about the same time (2014), expected that the price for one CH-53K could be about $ 91 million (excluding research and development, based on 200 produced copies) . Based on this, the assertion that modern traditional helicopters are, in principle, cheaper than a tiltrotor aircraft is not unambiguous.

The comparatively high mechanical and electronic complexity of the V-22 Osprey was also expected to result in very high operating costs. In 2015, the financial cost of one hour of flight of the V-22 Osprey was 9-10 thousand US dollars. How this compares to the costs for conventional helicopters is not easy to decide. The available data for calculating aircraft flight hour costs include many situational parameters (age and condition of the aircraft, intensity of operation, efficiency of maintenance organization, etc.). So, the information available for 2007 says that the price of an hour of flight of the CH-53E was about 20 thousand dollars.

Flight safety

The accident history of the V-22 Osprey includes nine crashes that claimed 39 lives. Of these incidents, four, with 30 fatalities, occurred during the testing phase between 1991 and 2000. The remaining five, with nine deaths, are after 2007 during the operational phase.

In addition, there were a number of flight incidents with less serious consequences. Accidents and incidents contributed significantly to the fact that the V-22 Osprey, at least temporarily, was not considered safe enough. Thus, flight accidents became the basis of the protests of the inhabitants of Japanese Okinawa in July 2012 against the deployment of the V-22 Osprey on the island.

The V-22 Osprey's safety concerns revolved around, in particular, the tiltrotor's behavior during autorotation and its susceptibility to the so-called toroidal vortex state ( Vortex Ring State, VRS).

The aircraft after the failure of both engines (occurs very rarely), using autorotation, must make a safe landing. This, however, is complicated by the fact that its propellers have a lower inertia, and therefore a lower ability for autorotation, than conventional helicopter rotors. This makes emergency landings from hovering below 500 m very dangerous, since such heights are too low to use the gliding capabilities of the wings.

At least one case (April 8, 2000) has been attributed to VRS. At the same time, experts note that the VRS effect can occur with all types of rotorcraft if certain descent parameters are exceeded during vertical descent.

Flight testing showed that the V-22 Osprey was not particularly vulnerable to VRS. In this state, it is more difficult to control than a conventional helicopter. The Marine Corps changed flight training, instructions, and procedures as a result of this accident. More advanced instrumentation was installed on the aircraft to help aircrews avoid VRS.

According to statistics, in November 2017, the US Navy achieved 400,000 flying hours on the V-22 Osprey. Many of them were carried out in difficult combat conditions. In February 2011, the MV-22s deployed in Afghanistan exceeded 100,000 flight hours. According to their results, the then commander of the US Marine Corps, General James AMOS (James AMOS), rated this model as "the safest or almost safe aircraft" in his arsenal.

In general, according to independent assessments, the history of the V-22 Osprey accident from today's point of view does not give any reason to consider it a particularly unsafe aircraft. The need for careful attention to the technical and flight features of a tiltrotor is not unusual in military aviation.

As a result, the conclusion regarding the results of the V-22 Osprey program indicates that this model performs the range of tasks for which it was developed. Moreover, based on the experience of the V-22, Bells, participating in the competition of the US Army program "Future VTOL System" ( Future Vertical Lift Program) is again developing a tiltrotor.

According to the magazine "Europäische Sicherheit & Technik"

In the early 1950s The French company SNECMA began experiments with annular wing aircraft. After experiments with unmanned models in 1956, tests of the S-400 Atar Volant began. Three years later, an experimental convertoplane with an annular wing C-450-01 Coleoptere was created. The Atar 101E turbojet engine with a thrust of 34.32 kN was used as a power plant. The first free vertical flight of the Coleoptere was made on May 6, 1959. However, on July 25, during the transition from vertical to horizontal in flight, the plane crashed, the pilot August Morel managed to eject.

By order of the US Air Force in 1955, the Ryan company built two aircraft with a vertical hull position in takeoff and landing modes. These delta-wing aircraft were equipped with Rolls-Royce jet engines with a thrust of 45.4 kN. The machine, named Vertijet, received the designation X-13 according to the classification adopted in the United States. Since on these jet aircraft the surfaces of the controls were not blown by air streams descending from the propeller, they did not have a sufficiently high efficiency at low speeds. Therefore, control in such modes was provided by means of a rotary nozzle. The pilot also had, as it were, two sets of control instruments. In December 1955, flight tests began, but at the first stage the aircraft was equipped with a temporary three-wheeled landing gear, which made it possible to take off and land like an airplane.

Undoubtedly, the most unusual airfield in the world was used to carry out vertical takeoff and landing of Vertijet. This plane did not descend to the ground, but settled on the wall like a fly.

The airfield was an ordinary heavy-duty trailer, the transport platform of which could be hydraulically raised to a vertical position. On the top of the trailer, between two powerful masts, a massive, strong cable was stretched. Vertijet clung to the cable with a special hook installed under the nose of the aircraft. Since the hook was out of the pilot's field of vision, the guidance of the aircraft during landing was carried out with the help of an operator located on top of the trailer. In addition, on the upper part of the "landing wall" there was a special beam 6 m long, along which the pilot could at least slightly orient the aircraft in space (this beam was marked with white and black stripes, allowing the pilot to determine how far he was from the landing cable).

The first flight with vertical takeoff and landing was performed only on April 11, 1957. The thrust-weight ratio of the device was 1.3, so the takeoff and landing were quite successful. Further tests were not carried out, one of the aircraft was shown as a static exhibit at international air shows. However, the military quickly became disillusioned with convertiplanes with a vertical position of the hull and, for reasons of “philanthropy”, stopped all research on them: even the most experienced test pilots, according to contemporaries, turned pale at the mere recollection of a vertical landing on such a machine. However, in the late 1970s nevertheless, a project of an absolutely fantastic “transforming aircraft” appeared - Nutcracker (Grumman). When performing vertical takeoff and landing, it “broke” in half in such a way that the cockpit remained horizontal, but things did not go beyond the project.