Bell XV-3 experimental tiltrotor

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Bell XV-3 is an American experimental convertoplane. He made his first flight on August 23 1955. The first transition from vertical flight to horizontal - December 18 1958 of the year. In total, more than 1966 test flights were performed by 250, which proved the fundamental possibility of creating a convertoplane with turn screws. The tests of this aircraft were deemed successful, so it was decided to create on its basis a device already with turning engines, which led to the creation of a convertoplan Bell XV-15.

The experimental Bell XV-3 had a large fuselage for 4 passengers, fixed wings with a span of 9,54 meters and a Pratt & Whitney R-985 engine, which developed a maximum power of 450 hp. The rotor-propeller, which was located on the console of each wing, was transferred to the required position using electric motors: upward for vertical flight, forward for horizontal flight.



In order to obtain an aircraft that could combine the features of the aircraft and the helicopter, many attempts were made to create a variety of rotary-winged vehicles, including turning screws, which in the west were called convertiplane, and in our country - a helicopter-plane. These aircraft were equipped with large-diameter rotary screws with hinged blades and a small load on the swept area, like in helicopters, which made it possible for such machines to make a vertical take-off with a relatively small power of the engine mounted on them.




Convertible screws were rotated directly from engines that could be installed in nacelles that rotate with screws, or from engine / engines that were located in the fuselage of the car or in separate nacelles, while turning to a different flight model turned only screws. During horizontal flight, the tiltrotor was controlled as an airplane - with the help of ordinary aircraft controls, and during the transition to vertical flight - as a helicopter, with the help of controlling the common and cyclic pitch of the propellers. It was assumed that tiltrotor in the event of a malfunction of the power plant will be able to land on an aircraft with the planning and partial inclination of the screws, or, like a helicopter, on the autorotation mode.

Bell XV-3

For many years, Bell conducted a large amount of research and experimental work in the field of creating convertoplanes, the work in this direction was led by designers Arthur Young and Bertrand Kelly, and later they were joined by Robert Lichten. At the competition held by the US Army in 1950 for the best design of an aircraft designed for front-line reconnaissance and rescue services, Bell presented a design of a tiltrotor with turning screws. In total, the commission reviewed 17 of various projects, of which the entire 3 project of the rotary-winged aircraft, including the Bell project, was selected. According to the results of the competition held in 1951, the United States Air Force signed a contract with the company for the construction of two experimental convertoplanes for the next flight tests of the vehicles.

The construction of the first convertible from Bell, which was originally designated Bell XH-33, and later Bell XV-3, was delayed, the work was completed only at the beginning of 1955, and the first official demonstration of the novelty took place in February of the same year. 10 August 11, the first vertical take-off and hovering flights were made, and then the transitions to horizontal flight, when the inclination of the propellers reached 1955 degrees (test pilot Floyd Carlson). In subsequent tests of converters that passed 15 on October 25 of the year in the air at an altitude of 1956 meters when the screws were inclined at 60 degrees, the unit lost controllability due to mechanical instability and fell, while Bell XV-20 was destroyed and test pilot Dick Stensbury as a result of the fall was seriously injured.




Due to the crash, further flight tests of the convertoplan continued only in 1958, on the second copy of the Bell XV-3. At first it was equipped with two-bladed screws, but soon they were replaced with three-bladed ones. For the first time, a complete transition from vertical to horizontal flight followed by vertical landing was performed on December 18 1958 of the year, test pilot Bill Quinlen drove the tiltrotor. In subsequent flights, the unit was able to develop the speed of 212 km / h at an altitude of 1220 meters. In 1962, this unit was transferred for further testing to the NASA Langley Research Center. In this center, Bell XV-3 successfully flew vertical modes and performed incomplete transitions to airplane mode with propeller inclination of 30-40 degrees.

Also, the tiltrotor was tested on a special stand, on which the full transition to the flight mode “in an airplane” was performed. When moving from helicopter flight mode to aircraft, the propellers inclined by 90 degrees using a worm gear from electric motors. The transition process usually took just 15-20 seconds. At the same time, the Bell XV-3 tiltrotor was able to continue flying at any intermediate position of the screws during the transition. In total, this tiltrotor performed more than 250 test flights and 110 complete transitions between flight modes, flying during this time about 450 hours. During these flights, the maximum speed of 290 km / h was reached, as well as the altitude of 3660 meters. Tests of the convertoplan continued in the 1965 year, but already in a wind tunnel. These tests were stopped due to the separation of the gondola with a screw and the damage received by Bell XV-3.

The Air Force and the US Army had very high hopes for the development of this type of aircraft, believing that convertible gliders were best suited for conducting reconnaissance, communications and rescue operations. Bell has created a number of projects of both military and civilian models of such rotary-wing aircraft. On a number of them it was planned to install two gas turbine engines located in gondolas under the wing, while the maximum speed was to be about 400 km / h.


Bell XV-3 experimental tiltrotor


The Bell XV-3 convertible had the same layout as ordinary planes. The layout, in which the screws were located at the ends of the wings, was recognized as the most simple and suitable: when turning them, the tiltrotor looked like a twin-screw transverse helicopter. When carrying out a vertical take-off, the flow from the propellers was inhibited by blowing the wing, which was the cause of the loss in the propellers, and the maximum speed of the convertiplane was relatively small due to the low power of the experimental aircraft.

Externally, the experimental tilt-rotor Bell XV-3 is a single-engine monoplane with two rotary three-bladed propellers, as well as a skid chassis of a very simple design, the chassis gauge was 2,8 meters. In this case, the aircraft fuselage was distinguished by good aerodynamic forms. A cabin with a large glass area was located in its nose. In this cockpit were a pilot, a co-pilot or an observer, as well as two passengers, instead of them it was possible to place a wounded man on a stretcher along with an orderly. The wing of the convertoplane was straight and had a relatively small area, as it was designed to create lift only at cruising speed. At the ends of the wing were small gondolas with turn screws. The wing cover could be removed by technical service representatives to access transmission elements. The wing also had retractable flaps and ailerons. The tail of the tail was the same as that of conventional aircraft - with a rudder, with a large vertical tail area, on the keel there was a stabilizer with an 4 span of a meter with elevators.

Because of its design, the Bell XV-3 has a number of unique features in operation. For example, the cross transmission, which was typical for multi-engine aircraft, was absent. In the event of a power plant failure, the Bell XV-3 screws were automatically brought to the vertical position, as a result of which the tiltrotor could be reduced to autorotation as an ordinary helicopter or an ordinary gyroplane. At the same time, propellers bent forward to create thrust, however, during horizontal flight, part of the lifting force was nevertheless created by the wing of the vehicle.




Most of the difficulties for Bell engineers delivered a selection of screws of the optimal diameter for the Bell XV-3 convertible plane. The thing was that large-diameter propellers were needed for the vertical take-off of the device, whereas in horizontal flight it was more advantageous to use small-size screws. Ultimately, the 7,6 meter was recognized as a compromise diameter of the turn screws. Three-bladed propellers of this diameter were located in the gondolas at the ends of the wing. The hubs of the screws had intersecting vertical and horizontal hinges located at a distance of 0,44 meters from the axis of rotation, as well as sway compensators. The screw bushings were closed with fairings. All-metal glued blades in the plan had a rectangular shape and geometric twist 20 degrees.

As the power plant on the experimental tiltrotor Bell XV-3 was used aviation radial piston air-cooled engine from Pratt & Whitney. It was the R-985-AN-1 and the engine had a maximum power of 450 hp. at 2300 rpm at an altitude of 450 meters and during takeoff. The engine was installed in the central part of the fuselage. Due to the insufficient power of the power plant, the maximum speed was limited to 280 km / h, although the tiltrotor showed a greater value during tests. Achieving higher speed was possible by replacing the engine with a more powerful one. In particular, there were plans to install a twin-shaft GTE Lycoming T-53, which developed a power of 825 hp.

After the completion of the Bell XV-3 tests, the idea of ​​a convertiplane in the USA was not abandoned. After him, a new model was born. The new aircraft was equipped with already turning engines. He received the designation Bell XV-15, he made his first flight in May 1977. And 19 March 1989 of the year, the Bell V-22 Osprey tiltrotor flew into the sky, which has been in service since 2005. He serves in the Marine Corps and the Command of Special Forces of the US Air Force. According to the 2016 year, more than 300 devices of this type were built in total, the delivery of these convertible planes to the US armed forces is still continuing.




Flight technical characteristics of the XV-3 convertoplane:
Overall dimensions: length - 9,2 m, height - 4 m, wing span - 9,5 m, diameter of the turning screws - 7,6 m.
Empty weight - 1907 kg.
Take-off weight - 2218 kg.
The power plant is a Pratt Whitney R-985-AN-1 HPD HP 450.
Maximum speed - 290 km / h.
Cruising speed - 269 km / h.
Practical range - 411 km.
Practical ceiling - 4600 m.
Rate of climb - 6,3 m / s.
Crew - 1 man.

Information sources:
http://www.dogswar.ru/oryjeinaia-ekzotika/aviaciia/4337-eksperimentalnyi-sam.html
http://www.k2x2.info/transport_i_aviacija/amerikanskie_samolety_vertikalnogo_vzleta/p2.php
http://www.popmech.ru/technologies/14617-samolet-vertolet-effektnyy-eksperiment/#full
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26 comments
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  1. 0
    August 29 2016
    Interesting. Osprey had ancestors.
    1. avt
      +4
      August 29 2016
      Interesting. Osprey had ancestors
      Believe it or not - and not only this one. I remember the variant with rotating wing planes with fixed four engines, it seems. And there was also a Bell "-ka", with which Cameron copied in his "Avatar" -X-4A
    2. The comment was deleted.
    3. +2
      August 29 2016
      There were also Canadian CF-84s that the Americans took to use, copied what they needed from them and broke it. Compared to which everything else is bullshit (even Osprey).
      1. 0
        March 31 2017
        Quote: Connie
        There were also Canadian CF-84s which the Americans took to use.

        ))) But the Yankees, who were not able to work with their heads, didn’t teach anything, IMHO
        Quote: Connie
        Compared to which everything else is bullshit (even Osprey).

        Amazing Awareness! In more detail, can you say something about CF-84? It’s rare, meager and inaccurate that I found on it ...
  2. 0
    August 29 2016
    Thanks to the author for the article.
  3. +1
    August 29 2016
    Here is a Canadian http://www.airwar.ru/enc/xplane/cl84.html.
    Osprey is here: http://www.airwar.ru/enc/craft/v22.html.
    Question: and what is better than a Canadian. Naturally, Osprey is better. It is much newer. Engines are better there, avionics - by itself. But, most importantly, they are even different in schemes!
    And for those who think that Canadians invented the convertiplane, read, at least this is http://www.bratishka.ru/archiv/2012/10/2012_10_14.php.
    There is more to come.
    Americans are investing huge amounts of money in research and development - it is not surprising that they are ahead of the rest. True, money doesn’t solve everything in science, so it happens that in some areas Americans are lagging behind. With money, they are good. It’s worse with motivation, especially in fundamental science - many Americans dream of becoming successful businessmen, not scientists, so they constantly have to buy scientists for this very money. Money, unfortunately, can do a lot. And if in any research and development you see money cut, while some in ripped jeans become the owners of half of the country's oilmen, then there will be no new developments - there will be a repainting of old tanks with new paint.
    1. +1
      August 30 2016
      The Canadian is better than Americans by head in that he has a rotary wing and a tail rotor. Therefore, from the most important thing, it can take off well shortened, is better controlled, and is safe with trim and rolls.
      The same fate as the CL-84 suffered before the Canadian CF-105 Arrow, then BAE Harrier-2 and the Soviet Yak.
      Even before getting von Braun's rocket command and still lagging behind, they crushed the entire world airship building (primarily German), through the undermining of the Hindenburg and the monopoly on helium.
      Americans steal everything from everyone and omit the initial development, or the whole country, therefore, ahead of the rest. They have to buy engineers and scientists, as well as select the best practices, not because they dream badly, but because they think poorly.
      1. +1
        August 30 2016
        The Americans XC-142A flew a year earlier. And why is it worse than the Canadian CL-84?
        1. 0
          August 30 2016
          All the worse, obviously did not think. Another tail boom with fixed screw, lack of a unified control system. Synchronizers on screws constantly broke.
  4. +1
    August 29 2016
    In general, I am delighted with the situation when some are rubbing industries, and scientists are accused of cutting the budget, some of whom do not want to receive the Nobel Prize because they don’t know where to give it.
    Not funny?
  5. 0
    August 29 2016
    By the way, on topwar there was an interesting article about mi-30: https://topwar.ru/20847-konvertoplan-mi-30-proekt.html.
    But this program was covered with a round non-ferrous metal product in the 90s, as well as much more. Correctly. And there’s nothing to rub the budget for all kinds of convertiplanes, when some even lack a jet for a regular personal business!
    1. 0
      August 30 2016
      When was the last time you saw the copper basin? In addition to all this and the An-2 "business jets" from the former USSR, they still rubbed all the non-ferrous metals. Little Estonia unexpectedly came out on top in the world in terms of their export, although then the ferry with their cargo sank, and with a large number of human victims.
  6. 0
    August 30 2016
    American scientists and engineers are no dumber than the rest. The problem is that there are not many native Americans among them. Apparently, they also dream no worse than the rest, not only about knowing everything that exists, but about making more money than anyone else. It seems to me that most of them simply do not understand how you can seriously engage in such nonsense as science instead of making money. Therefore, all the scientists in their films are crazy. The fact that they are buying them all over the world, of these scientists, is the true truth. By the way, that’s what really can be learned from them, is the enterprise and the ability to organize. In particular, they so wonderfully organized the world financial system that the rest of the world gives them a significant share of their GDP in gratitude for the evergreen pieces they painted. And I saw a copper basin last year in an antique store, but I hope that you understand that I express myself figuratively. By the way, the presence of coaxial control screws in the tail is not such an indisputable advantage. Another, or rather not one, node that can break, and this is reliability.
    1. 0
      August 30 2016
      The problem is that imported ones quickly fall to their level.
      The presence of a rotary screw is an undeniable advantage, you can compare how the American was controlled and how difficult it was due to the four propellers.
  7. 0
    August 30 2016
    The authors of the dispute knew about the existence of such a scheme, but, for some reason, did not choose it. I think for a reason. Most likely there were several, at least, conceptual designs, and most likely, their indicators were modeled and analyzed - in the end, we chose the option that flies. I do not presume to challenge the results of the work of a team of specialists who own modern methods of calculation and analysis, software and hardware, working in this problem for more than a year. I can’t imagine the level of stupidity that would allow, in the presence of many years of experience and all the necessary equipment, to draw less reasonable conclusions than we do, which have nothing of the kind. Believe me, a good scientific or engineering school possesses, among other things, such knowledge, and a flair that cannot be gleaned from any information sources.
    1. 0
      August 31 2016
      Well, why didn’t they elect her and Osprey got a goat so that George W. Bush refused to sit on the White House lawn? Maybe they didn’t understand what, or simply didn’t want to? Because it turned out cheaply, or for some reason else? As a result, we chose the option that flies worse than the Canadian.
      Let’s explain why the F-35B flew out in public 25 years later than the Soviet original? And why is he conditionally combat-ready now not on ships?
      Why the automatic docking system was never developed by the efforts of the American
      Quote: Dekabrev

      "a team of specialists who possess modern methods of calculation and analysis, software and hardware, working in this problem for several years."

      on your own, and what should be according to your ideas
      Quote: Dekabrev

      "a level of dullness that would allow, with many years of experience and all the necessary equipment, to draw less reasonable conclusions than we do,"

      and as a result, buy this system in Russia for your American mooring hub on the ISS as well as for their capsules?
      And what do they have "good engineering or science school"with flair and knowledge after that?
      How and after the F-35C began to crumble from less than a dozen landings, and why is this so with it - is understandable to any pilot, who can hardly restrain themselves from laughing at this "school" during an interview?
      https://www.youtube.com/watch?v=vGc4Npg1oy0
      https://topwar.ru/99506-palubnyy-f-35cpristupil-k-tretemu-etapu-ispytaniy.html
  8. 0
    August 31 2016
    And where does the F-35 and the failed node?
  9. 0
    August 31 2016
    The failed node, in fact, is understandable why. For many years the USSR exploited these nodes at its stations - why invent a lisapet.
    1. 0
      August 31 2016
      In addition to the node, this is also a guidance system. It is clear why the Americans themselves could not do this, and in the end they bought the Soviet one.
  10. 0
    August 31 2016
    Moreover, such "actions" are systematic.
  11. 0
    August 31 2016
    And how many years brought to mind the Tu-22? They didn’t bring it to the end, they had to redesign it. Only those who do nothing are not mistaken.
    1. 0
      August 31 2016
      T-4 was also abandoned due to the lack of variable sweep on it.

      Those who just steal, buy for pieces of paper and play on the stock exchange do not do it themselves. After alloying engineers and scientists from all the waves of all emigration in their "melting pot" again dropped to the general level.
  12. +1
    1 September 2016
    And here is my question:
    Are there those who are really interested in the topic of convertiplanes at VO who are interested in it?
    No, I understand that just talking, shooing, may be surprised and even just scold the very idea - this is from our nature! )))
    But on the case! How about this? Sincerely. smile
    1. 0
      1 September 2016
      Are you planning to fly somewhere on your own past customs snouts and nuts?
      1. 0
        2 September 2016
        bully No, you know, I invented and build https://patentscope.wipo.int/search/ru/detail.jsf
        ;jsessionid=0A98DC99A1C3115E65DD3E8237213277.wapp
        1nC? DocId = WO2015094020

        1. 0
          11 September 2016
          jet APU

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