Military Review

V-22: interesting, but in some places illogical


A tricot in flight. The angle of the nacelles 75 degrees (by eye)

Is it easy to fly a V-22 Osprey tiltrotor? I think many would be interested in how such a thing generally stays in the air. But how to find out? It is unlikely that the US Marine Corps will be so kind as to allow foreign pilots from unfriendly countries to handle this machine.

Nevertheless, there is some opportunity to look at this miracle of technology through the eyes of the pilot. I managed to find an interesting work by Scott Trail, defended at the University of Tennessee in May 2006, in which he examined the peculiarities of piloting the V-22 in instrumentation (instrument meteorological conditions, IMC), that is, in bad weather conditions. This work was written on the basis of a number of test flights and set itself the task of determining which configuration is best suited for such flights and how easy it is to fly a tiltrotor.

This, of course, is an unofficial test report, but it suits us. Mostly the article will follow this report.

A little bit about tiltrotor

The main feature of the tiltrotor is that its engines are located in two rotary engine nacelles installed at the ends of the wings. They can change their position in the range from 0 to 96,3 degrees (that is, 6,3 degrees back from the vertical position). The nacelle tilt has three modes: about 0 degrees - airplane, from 1 to 74 degrees - transitional mode and from 74 to 96 degrees - vertical take-off and landing mode.

In addition, the tiltrotor has a two-keel steering wheel, flaperons (aileron-flaps) on the wings, which can work both as flaps and ailerons. The propellers can be tilted in the vertical take-off and landing mode, and in this mode the flight is controlled by the inclination of the propellers and the difference in propeller pitch (when moving to the nacelle position 61 degrees, the propeller pitch is limited to 10% of normal and gradually decreases to zero in airplane mode; the pitch difference is turned off at speeds above 61 knots or when the position of the nacelles is less than 80 degrees); but also in transition mode, the control is carried out simultaneously by the difference in the inclination of the screws, flaperons and rudders. The screws have an adjustment of the installation angle, pitch and plane of rotation. In vertical flight mode, a propeller draw is used (it decreases to zero when the engine nacelles are in the range of 80 to 75 degrees) and the pitch difference of the propellers (to the maximum position of the engine nacelles is 60 degrees and decreases to zero at speeds from 40 to 60 knots).

The tiltrotor can land not only vertically, but also with mileage, like an airplane. At the same time, the minimum angle of inclination of the nacelles should be 75 degrees, the chassis is released at a speed of 140 knots, and the maximum landing speed is 100 knots.

The controls of the tiltrotor are generally similar to those of a helicopter and an airplane: the handle that controls the pitch and roll, the rotation pedals (unlike the helicopter, they control the rotation of the rudders), the engine thrust handle under the left hand. The position of the nacelles is controlled by a wheel mounted on the traction handle under the thumb of the left hand. This is exactly what is not on the plane or on the helicopter.

Cockpit of a convertiplane. On the left, under the red ribbon, is the traction control handle, on which you can see the white wheel that controls the angle of rotation of the nacelles

The tiltrotor has an automatic control system that constantly supports stabilization of the tiltrotor in flight position.

Manageability under different modes

How does he behave in different flight modes?

Airplane mode, nacelle position 0 degrees, speed 200 knots - control like on an airplane, speed is maintained in the range of 2 knots, heading within 3 degrees, altitude within 30 feet.

Transitional mode, nacelle position 30 degrees, speed of 150 knots - the control is the same as in airplane mode, but Trail noted tangible vibration and climb by about 30 feet when cornering.

Transition mode, position of the nacelles 45 degrees, speed 130 knots - the vibration increased, but did not affect the control; but the tiltrotor became less predictable, the speed ranged from less than 2 or more than 4 knots to the desired one, and the height ranged from a decrease of 20 and a lift of 60 feet.

Transition mode, position of the engine nacelles 61 degrees, speed 110 knots — the tiltrotor is well-controlled, speed within less than 2 knots and more than 2 knots from the desired, altitude fluctuated within less than and more than 20 feet from the desired. But Trail noted a strong vibration.

Helicopter mode, nacelle position 75 degrees, speed 80 knots — the tiltrotor is more controllable and more sensitive, deviates less from the desired flight parameters (speed within 2 knots, heading within 2 degrees, altitude within 10 feet), however, in this mode strong glide.

There are other interesting piloting features. It turned out that the tiltrotor is the fastest to gain altitude and decreases when the position of the nacelle is 45 degrees: when climbing - 200-240 feet per minute, with a decrease from 200 to 400 feet per minute. But it’s difficult to pilot a tiltrotor, more experience is required than with other flight modes. The V-22 can gain altitude and decline even faster, to 1000 feet per minute, with the pilot requiring the help of a commander.

It turned out to be difficult to find a photo of the flight in transition mode. In this photo, the angle of the nacelles (by eye) is about 45 degrees

The general conclusion of Trail is this. The tiltrotor is for the most part very good at handling and on the Handling Qualities Rating Scale, most maneuvers do not require pilot intervention or require minimal intervention (HQR 2-3). However, when the angle of the engine nacelles is 45 degrees, as well as when combining changes in the angle of the engine nacelles and maneuvering, the control becomes more complicated and the maneuvers require average or significant pilot intervention (HQR 4-5).

Approach Features

During the tests, several more flight modes for instruments were worked out, in particular, the approach approach and the unsuccessful approach with the loss of one engine (in the experiments it was simulated by thrust limit to 60% of the maximum).

The approach from the airplane mode is associated with some difficulties for the pilot, who must monitor the altitude, heading, speed and angle of the engine nacelles and respond to changes at the moment when the position of the engine nacelles changes, especially when the angle changes to 30 degrees. At an engine nacelle angle of 30 degrees and a speed of 150 knots, the landing gear cannot yet be released, so the pilot needs to quickly raise the nacelles to an angle of 75 degrees and slow down to 100 knots. At this moment, a slip occurs and you need to keep the tilt plane on course, as well as compensate for the lift of the machine that occurs at engine nacelles from 30 to 45 degrees. After switching to helicopter mode, the pilot needs to raise his nose and increase traction to maximum to reduce the rate of descent.

Approach in the configuration of nacelles 75 degrees, chassis released

When approaching, the pilot can move the engine nacelles to 61 degrees at a speed of 110 knots, while the tiltrotor gains from 50 to 80 feet in height and a speed of 10 knots is more desirable. There is also lateral vibration that distracts the pilot. However, in this configuration, the tiltrotor is easier to control, more stable and maintains speed within 2-3 knots from the desired one. The rate of descent is well controlled by traction. From this configuration, it is easiest to switch to a landing configuration, for which it is enough to drop 10 knots and raise the engine nacelles by 14 degrees.

You can also move the engine nacelles to 75 degrees during the flight and start the approach at a speed of 80 knots. At the same time, the tiltrotor can spontaneously deviate from the course by 1-2 degrees, which must be compensated. This configuration allows for a more accurate landing and a touchdown point.

In the event of an unsuccessful approach with the loss of one engine, the pilot should immediately put the engine nacelles to 0 degrees (the initial positions of the engine nacelles 30 and 45 degrees were worked out), in which case the tiltrotor loses 200 feet in height. Lifting is possible only when switching to airplane mode. With the initial configuration of 61 degrees nacelles, the transition to airplane mode with an unsuccessful approach becomes very difficult, as the tiltrotor becomes sensitive to changes in the angle of the nacelles. The pilot must move the nacelles very carefully so as not to accelerate the descent, and this maneuver requires a distance of at least 8 miles; during the maneuver, the car loses 250 feet in height.

Advantages and disadvantages

As far as one can judge from the description of tiltrotor control, the main difficulty is that the pilot needs not only to be able to fly in an airplane and in a helicopter, in simple words, but also to switch from one pilot mode to another in a timely manner when the position of the nacelles changes, and also make more efforts when piloting in transient conditions, especially when the angle of the engine nacelle is 75 degrees, when the tiltrotor becomes taut in control and acquires a tendency to slip.

In some places, the tiltrotor is illogical in management. For the most part, pilots fly it in airplane mode, but the fact is that when approaching and switching to the helicopter configuration, you must give full thrust, while the plane when approaching requires picking up thrust, for pilots it requires some skill and habit.

Each machine has its own advantages and disadvantages. The disadvantages of a tiltrotor include the fact that it has almost no autorotation in helicopter mode (it is, but bad: the autorotation speed is 5000 feet per minute), which significantly facilitates helicopter piloting. However, the tiltrotor has wings with their lift and planning ability (aerodynamic quality - 4,5, with a descent rate of 3500 feet per minute at a speed of 170 knots), in combination with various angles of the position of the nacelles this can produce interesting effects like simultaneous climb and speed when the position of the nacelles at 45 degrees. An experienced pilot can vary flight modes using a change in the angle of inclination of the nacelles (maximum 8 degrees per second, that is, a complete turn from 0 to 96 degrees takes 12 seconds). For example, the transfer of nacelles from 30 to 45 degrees occurs almost instantly, in a little over a second, and this mode allows you to sharply gain altitude and speed, which can be used, for example, when evading shelling from the ground.

V-22: interesting, but in some places illogical

In airplane mode, you can turn

In general, for an experienced pilot, this is a very good machine with additional features that are absent from both the aircraft and the helicopter. But for a beginner, this is a difficult car. Piloting this miracle of technology, of course, you can learn. However, this requires longer training (according to the US Marine Corps curriculum, 180 days are given for pilot training), and the flight requires more pilot attention.
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  1. cormorant
    cormorant 9 June 2020 05: 58
    Beautiful bird! If not for perestroika, our Mi-30 would also fly, but as they say, if only yes. And now everything, the technology is lost, we lag behind for a generation.
    1. Proctologist
      Proctologist 9 June 2020 12: 23
      I have seen in flight. Really impressive and very unusual.
  2. The leader of the Redskins
    The leader of the Redskins 9 June 2020 06: 16
    A tricot is like a bug.
    Aircraft manufacturers have such a joke - according to theory, from the calculation of the wing area / body weight, the beetle should not fly. But the bug does not know about it, and therefore flies!)))
    1. wehr
      9 June 2020 21: 28
      And if the beetle is taught theories, then he will not fly? laughing
  3. Nikolay R-PM
    Nikolay R-PM 9 June 2020 06: 19
    here it is the result of the work of a test pilot at LII and specialized research institutes, application centers and similar organizations: expansion of flight restrictions, development of new methods of piloting and using la.
    very curious is the application of changing the angle of rotation of the engine nacelles to control the tiltrotor. interesting, but is moving the v-280 propellers from helicopter to airplane configuration faster? or was it intended to be set within about 12 seconds, so that both the pilot and the self-propelled guns could catch a sudden disturbance in transition?
  4. Lontus
    Lontus 9 June 2020 07: 25
    The tiltrotor has absorbed the worst of the helicopter and airplane worlds.
    Not fast enough like an airplane, and not manoeuvrable like a helicopter.
    Suffers from wear of propeller blades and rotary engine mounts, high fuel consumption in "vertical mode", large radar signature.
    More expensive than a similar helicopter.
    And what do you get for it?
    Toothless transporter with greater speed and radius of action than a helicopter.
    Adopting it in the US was both a drink and a mistake.

    And with reliability, he multiplies the worst.
    If the propulsion system fails, the aircraft may try to plan; the helicopter will land on autorotation.
    The hovercraft can only fall. What he confirmed repeatedly.
    1. sp77ark
      sp77ark 9 June 2020 08: 44
      Designed for ILC for transporting cargo / personnel over long distances.
      It pulls 9 tons of cargo, flies at 1600 km, speed 500 km / h, sits at a point, folds up and is placed in the hangar of an aircraft carrier. Can you offer something better in return?
      You need to compare it with a "clean" tiltrotor, with the Valor V-280, but so far there is little information and operating experience on it.
      1. nalogoplatelschik
        nalogoplatelschik 9 June 2020 14: 18
        You wake up already. 9 tons of cargo at a speed of 500 km / h for 1600 km. you yourself believe in it? Padded jacket.
        1. sp77ark
          sp77ark 9 June 2020 20: 54
          She doesn’t notice commas lol
          Week on site laughing
          Looks like they flooded the troll. And obviously for the cause yes
          Lavrov's quote asks tongue
      2. nalogoplatelschik
        nalogoplatelschik 9 June 2020 14: 27
        A tiltrotor is a dead end branch of development. This was proved before the king of peas. But stupid, stubborn s want to prove the opposite. A flag in their hands and a drum on their neck.
        1. alert_timka
          alert_timka 9 June 2020 15: 26
          Why are you so nervous !? One should be more calm about what, how and who does what is doing there. And why immediately insults that all around are stupid, etc.!?
          1. ProkletyiPirat
            ProkletyiPirat 9 June 2020 17: 40
            Just apparently an avatar to match the author wink
    2. ProkletyiPirat
      ProkletyiPirat 9 June 2020 13: 24
      Quote: Lontus
      The tiltrotor has absorbed the worst of the helicopter and airplane worlds.

      1) It’s just that most people think that a tiltrotor is a hybrid of an airplane and a helicopter, THIS IS AN ERROR! rotor-based tiltrotor is not a hybrid, but an independent type of technology, he has his own problems and shortcomings, but many "bosses" sincerely believe that "if you collect design engineers for elephants and dogs, they will create an anteater."
      2) Most of the problems of the dispute are associated with paragraph "1", or rather because of the three consequences arising from paragraph "1"
      2.1) the problem of air filtration from impurities
      2.2) the problem of supercritical operation of the engine (partially referred to in the article as vibration)
      2.3) balancing problem
      due to points 2.1 and 2.2, the engine is "burned out" and is being replaced because its blades and bearings are flying
      because of point 2.3 there is an uncontrolled flight and the larger the mass of the cargo, the worse
      All three problems are solved extremely simply and corny, provided that the developers understand the essence of these problems.
      3) regarding the "high cost" of specifically disputing about some mi-8, your statements are extremely populists and do not stand up to criticism, just take and calculate the cost of aircraft and their basing points with a common denominator in the form "cover an area of ​​N sq. Km with air forces with a reaction time of T hours ", I will not reiterate my calculation (I have already posted it on VO, look if you are too lazy to count).
    KVU-NSVD 9 June 2020 07: 29
    The article is interesting, but complicated for a layman.
    (180 days are allocated for pilot training according to the US Marine Corps curriculum),
    The question is - why have pilots been trained at the school for years, and they have 180 days? It is clear that there is simply a pilot of a narrow specialization, and we have an officer with a higher education and a future commander, but still, does it make sense to train separately pilots for certain planes in training and pilot-commanders in schools? Could this solve the problem of lack of flight personnel and the mobility of pilots in wartime?
    1. Kostya Lavinyukov
      Kostya Lavinyukov 9 June 2020 07: 44
      Apparently, this means not a complete training cycle, but only retraining on a specific machine. The basic education of the pilot is unlikely to be shorter.
    2. Krasnoyarsk
      Krasnoyarsk 9 June 2020 07: 58
      Quote: KVU-NSVD
      The article is interesting, but complicated for a layman.

      Not only that, but the translation is not complete. Translate, article, translate in full. Those. and feet with pounds to the metric system .. For a better reader experience.
      1. sp77ark
        sp77ark 9 June 2020 08: 46
        Yes, and a link to the original would not hurt.
    3. wehr
      9 June 2020 12: 46
      Retraining, of course.
      There the commander has an interesting training: first 66 days training in mechanics, and then 109 days - the command course.
  6. gridasov
    gridasov 9 June 2020 10: 43
    In order to understand the complexity of the operation and control of the propellers of the tiltrotor, I recommend taking the grinder and moving the plane of rotation from a vertical position to a horizontal one. Everyone experience the beauty of transients. Moreover, the work of two such systems with changing axes of precession is generally a very complex process. Moreover, American experts point out a key problem - this is a very large diameter of rotation of the blades. Therefore, all questions are initially for science and physicists. The task is how to reduce the length of the blades and maintain the density of air flows, how to balance the work of virtually two unipolar motors at transitional moments of changing the direction of the rotation axes.
  7. The comment was deleted.
  8. Sergey M. Karasev
    Sergey M. Karasev 9 June 2020 15: 34
    The tiltrotor can land not only vertically, but also with mileage, like an airplane.

    This is what height should the landing gear be so that the screws on the take-off do not break ???
    1. The comment was deleted.
    2. irontom
      irontom 9 June 2020 15: 48
      Have you read the article? The pilot will detail the flight and landing modes for you.

      that's how he lands on an airplane
  9. prodi
    prodi 9 June 2020 15: 50
    perhaps a more correct continuation of the Valor scheme would be the ability to transfer thrust when turning the screws from them (from the screw) to the jet of the same engines, in any case, when landing, it seems more reasonable
  10. andrew42
    andrew42 9 June 2020 16: 45
    To give an objective assessment of the feasibility of such a contraption, we need a detailed report by an experienced pilot, flying a lot of hours. What does not shine for us. And so, an impressive contraption. It seems that Colonel Kuoritch sitting in the cockpit, dissecting the sky of Pandora :)
    1. agond
      agond 9 June 2020 20: 48
      The likelihood of an accident of such a scheme is two times higher than in a classical or coaxial one, the tiltrotor flies well while the symmetry of the forces acting on it remains, as soon as it is broken, this is the end,
      1. sp77ark
        sp77ark 9 June 2020 21: 18
        Don't confuse concept with implementation. Avatar also has a tiltrotor. And the diagonal screws can compensate for the loss of the motor. And Osprey is the first and is sharpened for the task and dimensions.
      2. Revolver
        Revolver 10 June 2020 03: 04
        Quote: agond
        The likelihood of an accident of such a scheme is two times higher than in a classical or coaxial one, the tiltrotor flies well while the symmetry of the forces acting on it remains, as soon as it is broken, this is the end,

        The screws are interconnected by a rigid shaft passing through the wing. Even if one motor dies in helicopter mode, there will be no tipping moment from stopping one screw. But this system of shafts in some modes gives a tangible vibration, as you do not balance them.
  11. grumbler
    grumbler 9 June 2020 21: 26
    In the form in which it is implemented, for me personally, this is an engineering curiosity.
    The idea of ​​turning the engine nacelles whole, times. Two, I represent the enormous loads arising from the rotation of uncompensated angular momenta of the multi-meter machine screws.

    I understand, they really wanted to get a "high-speed lifting helicopter" or "an aircraft with a helicopter takeoff and landing", because the military really needs a car with such properties.
    And it flies. But, until we learn how to efficiently convert turbine energy into electricity and deliver it to compact, lightweight electric motors in nacelles, until then it will be a technical curiosity.

    Or even switch from classic blades to some kind of flexible "ribbon loop-shaped wings" (something like woven Mobius loops) made of carbon-plastic, which will transform in flight, depending on the flight mode (and in the hangar they can be folded, like flower petals or insect wings).
    1. agond
      agond 9 June 2020 21: 43
      Quote: grumbler
      But, until we learn how to efficiently convert turbine energy into electricity and deliver it to compact, lightweight electric motors in nacelles, until then it will be a technical curiosity.

      That's right ... and even if there is an ideal electric drive of screws, it still will not help much, because damage to one part in a tiltrotor is much more dangerous than the same damage in a classical scheme.
      1. grumbler
        grumbler 10 June 2020 22: 44
        On agond Yesterday, 21:43 PM:
        Compact e-mail motors, at least, would make it possible to place 2 smaller propellers on one engine nacelle (multi-blade and in an annular nozzle to increase efficiency), with counter-rotation for mutual compensation of angular moments. And not these "windmills", causing conflicting feelings :)

        On wehr Yesterday, 21:46 PM:
        As far as I remember, there the nacelles are attached to the console through an annular bearing of a relatively large diameter - it will certainly distribute the load. But...

        It seems to me that the design of the Bell X-22A (1966) with rotary 4 screws in ring nozzles is much more beautiful (see P. Bowers "Lethal apparatus of unconventional schemes", Mir, 1991).
    2. wehr
      9 June 2020 21: 46
      If we talk about engineering oddities, it is not very clear why they attached the engine nacelles to the ends of the wings. It would be more logical to place them in the slot in the wing. Then the rotary mechanism would have two fulcrum points, instead of one, and would be strengthened by the support on the wing spar. It would turn out more reliable.
      In the wingtip could be put aileron.
    3. sp77ark
      sp77ark 9 June 2020 23: 15

      Curtiss-Wright X-19, 750km / h at an altitude of 6km, range of 850km with 450kg load. And this is 1960!
      There were problems with the control system, so I did not go.
      And if you replace it with a modern EMDS?
      Today, any quadcopter with independent e-mail. motors are perfectly controlled and makes somersaults in the air. So "never say never"!
      All objections of the type "everything that is above our capabilities is below our dignity."
  12. eklmn
    eklmn 9 June 2020 23: 55
    For the curious:
    find on the 2014 YouTube “Air Warriors: Season 1 episode 3”
    There is a 50 min film about the V-22 from the moment of construction to the current day, its problems, pluses / minuses.
    Knowledge of English is mandatory.

    The V-22 release program was scandalous. In 1986, the Pentagon ordered helicopters in the amount of $ 2.5 billion, but by 1988 the entire order was already worth $ 30 billion - 15 times more expensive! The panic began! The Pentagon refused a helicopter; it remained only with the Marines.
    Between 2008 and 2011, the estimated cost of the V-22 grew by 61 percent, mainly for maintenance and support.
    In 2001, Lt. Col. Odin Lieberman, commander of the V-22 squadron at the New River Marine Corps, was relieved of his duties after being charged with instructing his unit to fake maintenance records to make it more reliable. Three officers were involved in the role in the fraud scandal.
    On September 28, 2005, the Pentagon officially approved full-scale production, increasing from 11 V-22 per year to 24–48 per year by 2012. Of the planned 458, 360 for the USMC, 50 for the USAF of the US Air Force and 48 for the Navy with an average cost of $ 110 million per aircraft, including development costs. The Navy hoped to save about $ 10mn through a five-year production contract in 2013. Each V-22 cost $ 73 million in the budget for fiscal year 2014.
    On Wiki, you can find many military operations involving V-22. But his main occupation is the delivery of goods to areas of climatic disasters - hurricanes / tsunamis ....
    It takes on board up to 30 tons of cargo, the possibility of refueling in the air allows you to fly unlimitedly far.
    By the way, it can fly on one engine, because there is an axis connecting both engines.
    1. sp77ark
      sp77ark 10 June 2020 00: 11
      Well, not 30t, but 9t.
      The 30T will take on the development of the V-22, a Bell Boeing Quad TiltRotor (QTR) project. To replace Hercules. Under study.
      1. eklmn
        eklmn 10 June 2020 02: 19
        You are right, as always!
        “Osprey can carry 24 people or 9 tons of internal cargo, or 6.8 tons outside.”
        Thanks for clarifying!
  13. Job74
    Job74 10 June 2020 12: 34
    A tiltrotor is clearly expensive, as is customary with amers. Purpose - vertical capture of the battlefield when landing from aircraft carriers. Dear toy, the Americans, as always, solved a rather difficult technical problem with money bags. We are unlikely to build such devices, if only because the high-speed helicopter is somehow more familiar and cheaper. And by the way, we had Ka-22 at one time, ended in disaster and oblivion. Aviation should be present at sea, but today they don’t put a propeller on the fighter, and ours need to figure out how to drag jet technology into the ship.
    1. agond
      agond 10 June 2020 20: 00
      A circuit with 4 screws, like a miniature in two less reliable circuits with 2 screws, not to mention the fact that in a 2 screw circuit it is still possible to connect both engines with a synchronizing shaft, what to do when there are 4 of them
  14. Falcon5555
    Falcon5555 11 June 2020 02: 45
    The screws have an adjustment of the installation angle, pitch and plane of rotation.

    Isn't the installation angle and pitch the same thing?
    Does he have a swashplate?
    How he maintains controllability in a transitional position (angle of about 45 degrees) - I personally do not understand.
    Can he hang and evacuate people from land or water (climbers, drowning sailors), or can he completely drown them with jets of air and exhaust engines?
  15. nalogoplatelschik
    nalogoplatelschik 10 August 2020 14: 34
    This is a dead-end branch. All this is passed along and across. Declared worthless and consigned to oblivion. A long time ago.
  16. PROXOR
    PROXOR 31 August 2020 12: 05
    As for me, a rotary nozzle like the Fu-35 would be more convenient. Then there would be no need to deploy the entire engine entirely. And it would not even be a tiltrotor, but a vertical takeoff and landing aircraft.