Hillson Bi-Mono pilot aircraft (UK)


Aircraft Bi-Mono with an upper wing of increased scope. Photo by Aviadejavu.ru


It is well known that a biplane compares favorably with a monoplane with higher takeoff and landing characteristics. Monoplane, in turn, bypasses the competitor in all other flight modes. During World War II, the British company F. Hills & Sons (Hillson) tried to create an aircraft that combines the best qualities of these two architectures. The first experimental sample of this kind remained in stories called Bi-Mono.

Ideas without support


At the very beginning of World War II, Hills & Sons received several lucrative military contracts, but its management did not intend to stop there. In the fall of 1940, the commercial director of the company, U.R. Chown made a curious suggestion. For the Royal Air Force, a fighter-interceptor with a special design should have been created.

The concept proposed the construction of an aircraft from affordable and cheap materials with a minimum number of expensive components. This fighter was intended for air defense, and therefore had to take off from any sites. To improve take-off and landing performance, an original aerodynamic design was proposed. The fighter was supposed to take off on two wings in a biplane configuration. After take-off and reaching a predetermined height, the upper wing should be dropped to reduce drag and increase LTH. This concept is called slip-wing ("slipping wing").

The military department got acquainted with the proposal and was not interested in it. The idea of ​​dropping the wing after takeoff was considered overly bold and dangerous. In addition, at that time, the UK was not able to disperse forces on all the proposed projects.

Hillson Bi-Mono pilot aircraft (UK)
Flying with planes of equal magnitude. Photo Airwar.ru

The project from Hillson did not receive support, but the company found the opportunity to continue it. On her own initiative and on her own, she decided to develop and test an experimental technology demonstrator aircraft. The presence of such a sample could affect the opinion of the military.

32 day


The experimental aircraft was developed at the Hillson Design Bureau. The chief designer was Ernest Lewis. The project was not particularly difficult, and it was possible to complete in just 32 days. The proposed aircraft was not intended for real service, but could show the capabilities of slip-wing.

They involved the Royal Aircraft Establishment Institute. In his wind tunnel, we tested the model of the aircraft and got positive results. In all modes, the model behaved correctly. Relieving the wing at all speeds was safe and allowed the flight to continue. However, there was a significant change in the aerodynamics and behavior of the aircraft.

The company found opportunities for the construction of the aircraft, although this process has already taken 72 days. However, in early 1941, the prototype was ready for withdrawal to ground and flight tests.


General types of experimental aircraft. Figure Alternathistory.com

The original design aircraft was called Bi-Mono - an abbreviation for "biplane-monoplane." Other names were not used. In addition, the prototype did not even have a registration number.

Monoplane Biplane


Bi-Mono was extremely simple in design and small in size. The fuselage had a steel frame and linen sheathing. Both wings were built of wood using the basic technologies of the time. The length of the aircraft did not exceed 6 m, the scope of the fixed lower wing - 6,1 m.

At the design stage, two aerodynamic schemes were worked out. The first offered a half-wing with an upper wing span of 8,8 m. The second option provided for the use of two wings of the same wingspan of 6,1 m. Both wings were built for testing.

Own wing of the aircraft received a profile of RAF 34, had a direct center section and consoles with a small sweep angle. On the trailing edge were placed ailerons of increased area with the required efficiency. The upper wing was much simpler - it had a straight leading edge and rounded tips. Profile - Clark Y. The wing was fixed on the plane with the help of a central lock (on the lantern) and a pair of struts on the center section.


Takeoff in a biplane configuration. Photo by Aviadejavu.ru

In the nose of the fuselage, an air-cooled de Havilland Gipsy Six engine with 200 hp was installed. with two-bladed propeller. In the early stages a wooden screw was used; then applied metal.

Behind the power plant was a small cabin with a large lantern, which gave a good overview in all directions. The binding of the lantern was part of the power set and took on the load from the upper wing.

The plane received the simplest three-point fixed gear. The main racks were equipped with fairings.

Without the upper wing, the height of the aircraft was 1,93 m, with a wing of 2,13 m. The area of ​​the lower wing was 6,13 square meters, the total area of ​​the two planes was 12,3 square meters. The total take-off weight is only 880 kg.

Flight experiments


The pilot Bi-Mono was ready for the spring of 1941, and tests began soon. The car was checked in the configuration of a monoplane and a biplane with two variants of the upper wing. In both cases, she behaved normally and showed acceptable characteristics. The next step was to be tests with the discharge of the upper wing.


Flying after dumping the upper wing. Photo Airwar.ru

For safety reasons, they decided to perform such tests over the sea. To do this, the aircraft was flown to Blackpool, on the coast of the Irish Sea. The first wing drop was scheduled for July 16.

On that day, Bi-Mono, under the control of pilot P.Kh. Richmond took to the air and flew towards the sea. Next to him was an understudy plane with project managers, RAE representatives, and cameramen. The aircraft reached a safe area and climbed to a height of 1370 m.

The test pilot pulled the lock control lever and dropped the upper wing. Under the action of the lifting force, it went up, after which there was a stall, and the part fell into the water. Due to the wing detachment, the aircraft lost some of its lift and “fell” by 80 m. The aircraft’s characteristics changed significantly, but remained within the normal range. P.Kh. Richmond successfully completed the flight and landed.

Shortly thereafter, the pilot aircraft was handed over to Aeroplane and Armament Experimental Establishment (A & AEE). At this stage, the car was slightly modified - in particular, a new metal screw was installed. Military experts also conducted a lot of test flights and experiments, according to the results of which a voluminous report appeared.

From experienced to combat


Tests by the development company, KVVS and A & AEE showed the full potential of the original design. It was found that a plane with a slip-wing can indeed combine high performance on take-off and other flight modes. This design provided take-off from unprepared sites of a smaller area, but did not limit flight and combat qualities in solving problems.


On the ground with one wing. Photo by Alternathistory.com

However, not without criticism. It was mainly associated with the relative complexity of the project and non-optimal economic features. The upper wing was in fact disposable: an unacceptable structural damage occurred during the fall. The production of such a unit that meets all the requirements was quite expensive. The use of any means of saving the wing complicated the project, but did not guarantee the desired savings.

However, the concept as a whole was considered viable and suitable for further development. F. Hills & Sons received an order to continue work, as well as the necessary financial and organizational support. She was ordered to design, build and test a modification of the Hawker Hurricane Mk.I serial fighter with a dropable upper wing.

This pilot project received the working designation FH.40. Such an aircraft successfully reached the flight test steel and demonstrated the prospects of slip-wing in the context of combat aviation. The FH.40 project is also of great interest and worthy of separate consideration.
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  1. Insurgent 8 March 2020 06: 13 New
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    Bi-Mono was extremely simple in design and small in size.

    Monstrously "squeezed" sizes, as for a fighter with whom the plane was conceived, just did not leave space to accommodate at least the minimum acceptable weapons for 1941 and the placement of ammunition.

    Wonderful, the British, in their own way ...
    1. Constanty 8 March 2020 10: 11 New
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      It was not a combat aircraft, but a technology demonstrator to confirm (or not) the assumptions.
      If successful, a completely different aircraft will be produced with the appropriate payload and such technical solutions. In the USSR, before the war, they also experimented with Biplane monoplans, but basically this was not decided by the fall of the upper wing, but by folding the lower wing.
      1. Insurgent 8 March 2020 10: 33 New
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        Quote: Constanty
        It was not a combat aircraft, but a technology demonstrator to confirm (or not) the assumptions.

        They say that there are (existed?) "Dead end branches of evolution", and this whatnot, along with the assumptions of the "gloomy British genius", is apparently from the same branch.

        Conceived by the dead plan, the dead and born.
        1. Constanty 8 March 2020 10: 48 New
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          Rome was not built in one day.
          Sometimes, in order to find the right solution, you have to make a few mistakes before. This was invented by the British, for example, in the USSR Shevchenko, Nikitin IS-1 (2). Bell X-5 was not invented immediately to reach the F-111 or MiGa-23
          1. Insurgent 8 March 2020 10: 56 New
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            Quote: Constanty
            Sometimes, in order to find the right solution, you have to make a few mistakes


            Bugs not freaks.

            Prototype Messerschmitt Bf 109

            This is what they do when they want to have “output” not “something”, but SA-MO-LET.
            1. Constanty 8 March 2020 11: 50 New
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              Do you understand the difference between a prototype and a technology demonstrator ?, because it doesn't look like this.

              Messerschmitt Bf 109 technology demonstrator was Bf 108 Taifun which no one makes silly accusations
              they just didn’t leave room to place at least the minimum acceptable weapons for 1941 and to place ammunition.
              This was not his role, since no one was considered a base for fighters Experimental Hillson Bi-Mono.
      2. vladcub 8 March 2020 15: 43 New
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        The idea, as they say, "was in the air", and who first thought of this?
    2. novobranets 8 March 2020 12: 25 New
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      Most likely the airplane in the photo was blinded cheaply and angrily in order to test the idea itself. It’s just not entirely clear why such an aircraft is needed, a short take-off, of course, is good, but its landing speed still remained high.
      1. Simargl 8 March 2020 21: 09 New
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        Quote: novobranets
        Most likely the airplane in the photo was blinded cheaply and angrily in order to test the idea itself.
        Just think about it!
        The experimental aircraft was developed at the Hillson Design Bureau. The chief designer was Ernest Lewis. The project was not particularly difficult, and it was possible to complete in just 32 days. The proposed aircraft was not intended for real service, but could show the capabilities of slip-wing.


        Quote: novobranets
        It’s just not entirely clear why such an aircraft is needed, a short take-off, of course, is good, but its landing speed still remained high.
        The plane lands, nevertheless, more easily: both the pilot sweated and the ammunition was shot, and the fuel runs out ...
  2. Same lech 8 March 2020 06: 23 New
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    Mdaa ... from the section of jokes British scientists.

    British scientists crossed crab sticks and got crab crosses.
    1. Insurgent 8 March 2020 06: 35 New
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      Quote: The same Lech
      from the section of jokes British scientists

      Is it a joke? I don’t presume to say, but involuntarily, of course, the question arises: What were they thinking about, creating IT?
      1. Kote Pan Kokhanka 8 March 2020 07: 06 New
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        Everyone goes crazy in his own way, especially mastering budget money.
        1. Alf
          Alf 8 March 2020 07: 56 New
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          Quote: Kote Pan Kokhanka
          Everyone goes crazy in his own way, especially mastering budget money.

          Well, they worked out the Hurricane variant with a dropable wing, and there was a large fuel tank in the upper wing.
          1. Kote Pan Kokhanka 8 March 2020 09: 15 New
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            Time for experiments and searches for solutions to aerodynamic problems that time threw up!
            According to the Hurricane, the system worked out, but was not accepted into service! Although the walker will master the walk !!!
            1. mr.ZinGer 8 March 2020 09: 40 New
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              I do not like modern aviation, the search for a solution comes down to optimizing computer models.
              The linearity of its development is visible for the next decades.
              Alas, there is no romanticism; creative intuition has faded into the background.
              The period of 30-60 years is the most interesting in my opinion in the history of aviation.
              1. Alf
                Alf 8 March 2020 21: 04 New
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                Quote: mr.ZinGer
                The period of 30-60 years is the most interesting in my opinion in the history of aviation.

                Wow, such freaks turned out, it’s kindly expensive to see what the French are worth. And they flew and fought!
          2. volodimer 8 March 2020 12: 05 New
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            FH.40 Hurricane

            After shooting the upper wing, a completely ordinary Hurricane was obtained.
            I think that if Spitfire began to be modernized immediately, then for the landing in Normandy they received a plane that would have a range that allowed them to accompany the bombers.
            And so, everything died out.
            1. Alf
              Alf 8 March 2020 20: 10 New
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              Quote: volodimer
              I think that if Spitfire immediately began to modernize,

              Did Spit not immediately begin to improve?
        2. mr.ZinGer 8 March 2020 09: 08 New
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          Yes, in the Soviet Union they tried to solve this problem more elegantly (Bakshaev and Shevchenko planes).
  3. bk0010 8 March 2020 14: 20 New
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    When I came up with a similar car in my childhood, I had the idea of ​​lowering the upper wing to the lower wing after take-off, and lifting it back before landing, but dropping it ... Such mismanagement could not even have crossed my mind!
    1. Alf
      Alf 8 March 2020 20: 15 New
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      Quote: bk0010
      When I came up with a similar car in my childhood, I had the idea to lower the upper wing to the lower one after take-off, and lift it back before landing,

      I dare to upset you, such an idea came to Shevchenko and Nikitin much earlier, in 1939, it was embodied in metal and was called IS-1, 2. Only there the lower wing was removed to the upper.
      1. bk0010 8 March 2020 20: 55 New
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        Not upset at all, thank you. By the way, now I can justifiably say that in the USSR back in 1939 there was an aircraft with variable wing geometry!
        1. Alf
          Alf 8 March 2020 21: 02 New
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          Quote: bk0010
          Not upset at all, thank you. By the way, now I can justifiably say that in the USSR back in 1939 there was an aircraft with variable wing geometry!

          Only the term "variable wing geometry" means the mobility of the wing, and here two wings turned into one. God knows how to classify it .. recourse
          1. mr.ZinGer 8 March 2020 22: 27 New
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            The wing area has changed, which means the geometry has changed, everything is correct.
            1. Alf
              Alf 8 March 2020 22: 44 New
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              Quote: mr.ZinGer
              The wing area has changed, which means the geometry has changed, everything is correct.

              Well, tady Oh! laughing
              1. dmmyak40 10 March 2020 17: 04 New
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                Most importantly, the first aircraft with a variable wing configuration - RK-I design G.I. Bakshaev. Moreover, a fairly successful prototype was. And this gave reason to work further in this direction.
  4. Lontus 9 March 2020 00: 46 New
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    Potential Benefits:
    1. Take-off from short platforms
    2. Take-off in high mountains (it was very important in the mountains of Afghanistan, for example)
    3. Take-off of supersonic aircraft
    4. Subsonic barrage of supersonic aircraft - wing reset, if necessary, switch to supersonic mode
    5. Wing additional tank.

    Problems:
    1. the wing is a pity, we must somehow save
    2 for the additional mass of the wing and attachment points requires a heavier and overall landing gear