Military Review

Instead of a turbine - a fiery motor


Let's dissolve a bit of MAXA theme, recalling that 75 years ago, 28 August 1940, for the first time, the Caproni Campini N.1 jet aircraft flew off the runway of the Milan airfield Talledo. He was the world's first two-seat jet machine.

Italian reactive approach aviationembodied in the project by engineer Secondo Campini, and in metal by the famous aircraft manufacturer Kaproni, was very different from German, and not for the better. If the Germans made the main bet on gas turbine engines, the Italians tried to ensure that the compressor does not work from a gas turbine, but from a conventional piston engine. As a result, they built a paradoxical power plant with a thrust of only 700 kgf, consisting of a jet combustion chamber, an afterburner and a separate three-stage axial compressor with an external drive. At the same time, the 12-cylinder Isotta-Fraschini engine, which rotated the supercharger impellers, developed a power of 900 horsepower.
"Caproni-Campini" turned out quite heavy and cumbersome: the length of the fuselage - 13,1 m, wing span - 15,85 m, take-off weight - 4200 kg. For such a colossus, the jet engine turned out to be too thin, so the plane, despite its good aerodynamics, demonstrated very low flight characteristics during tests. Even with the afterburner on, the speed did not exceed 375 km / h, and in the discharged mode, Caproni-Campini produced no more than 330. The height of the 1000 meters of the aircraft gained as much as 9 minutes, that is, its rate of climb roughly corresponded to the aircraft of the First World War.

It is safe to say that if only an 900-strong piston engine with a drive to an ordinary propeller was installed on this machine, it would fly no worse, and perhaps even better. In general, the combined power unit, in which the gasoline engine runs only on the compressor, clearly demonstrated its inferiority, and the aircraft with such motor units have never been built anywhere else.
True, after the war, the I-250 (MiG-13) fighter was produced in a small series, in which a piston engine was also used to drive a jet engine compressor. But for the 250 XR, only an additional afterburner thrust was created, and the main thrust was provided by a screw. This scheme was also not very successful and quickly lost in competition with the TRD.

Layout scheme "Caproni Campini". On the left, the in-line piston engine and a three-stage axial compressor are visible, on the right is a jet engine with an afterburner, and in the center are fuel tanks.

Ground tests of a jet engine with the fuselage tail section dismantled.

Caproni Campini was built in duplicate. On the left - their fuselages in the assembly shop, on the right - one of the airplanes on the airfield.

The Caproni Campini had an all-metal construction, very clean aerodynamic shapes and retractable landing gear.

One of the copies of the aircraft was preserved and exhibited at the Milan Museum of Science and Technology.
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  1. fa2998
    fa2998 6 September 2015 08: 35 New
    The power plant is a dead end branch. Judging by 2 engines, each is supplied with fuel, and each has its own efficiency and weight. The only aircraft with such a SU could do business is a Japanese "Oka" airplane for a kamikaze. A light aircraft, with a small range and price. And he won in speed (hard to knock down). The Japanese did not have enough time. Article is a plus! hi
    1. Rus2012
      Rus2012 6 September 2015 08: 56 New
      Quote: fa2998
      The power plant is a dead end branch. According to the 2 engine, each one is supplied with fuel, and each has its own efficiency and weight.

      ... to every little bird - its own sixth!
      I-250 - it would be quite out of place in the line of piston aircraft.
      That's what he thought for -
      The SS.2 power plant was placed inside the fuselage, which had a frontal air intake. One of its components was the Isott-Fraschini охлаждения Astro-7 X 40 воздушного air-cooled piston engine, which powered the air-jet engine compressor. At the same time, unlike the SS.1, the piston motor was located behind the compressor, so that its heat could be used to increase the energy of the air passing through the WREC. Having passed the compressor, compressed air was supplied to the combustion chamber, where there was a further increase in its temperature. The thermal energy thus accumulated during the outflow of air through an adjustable nozzle was converted into kinetic and created the reactive effect necessary for the flight.

      Although such a propulsion system almost eliminated the heat loss associated with the release of exhaust gases into the ambient air and cooling by the external air flow of the piston engine, it had a significant drawback. The fact is that with a decrease in the flight speed of such a power plant, the thrust decreased significantly, while the propeller group was the opposite. In this regard, the Italian aircraft had a very long take-off run.

      As a result of the research carried out at TsIAM, the team led by K.V. Kholshchevnikov and A.A. Fadeev managed to choose a more rational scheme of the WRC. Their power plant consisted of a reciprocating piston motor with a variable pitch propeller and an axial single-stage compressor driven into rotation by the same motor through a two-speed transmission. The motor was placed in the usual way, and the compressor was in a tunnel, the inlet of which was brought into the frontal part of the aircraft. Behind the compressor was a combustion chamber and a gas channel, ending with a jet nozzle with adjustable flaps.

      In this scheme, the power developed by the piston motor was transmitted simultaneously to the propeller and to the compressor. On take-off and cruise flight, its main consumer was a propeller, while the compressor rotated in lower gear, and fuel was not supplied to the combustion chamber. To increase the speed to maximum, the higher gear of the compressor drive was switched on, and fuel was supplied to the combustion chamber. At the same time, the decrease in propeller thrust was abundantly compensated by the resulting jet thrust. According to calculations, the total total equivalent power of the power plant, called E-30-20, taking into account the jet tailpipes, should be about 3000 hp. Due to the high fuel consumption, the WRC was planned to be used only as an accelerator, designed for short-term use in air combat conditions.
      1. Rus2012
        Rus2012 6 September 2015 09: 02 New
        At one time, I had occasion to meet with the authors of the power plant for I-250 ...

        And the topic, even at the end of 70xx, continued to advance very smoothly. Clear business, not for combat jet aircraft, but for tasks at the junction between piston and turbojet.
        The calculations of the effectiveness of those and other schemes ...
        1. gridasov
          gridasov 6 September 2015 11: 24 New
          It’s worth understanding. that thermodynamic processes in turbines are complex. However, the approaches for calculations are exclusively "standardized", which is for low-potential, and for high-potential. And even there is no such separation as methods for analyzing these processes. Therefore, there are objective limits to the fact that it is possible to accurately model both the processes and installations themselves, and even more so as promising ones. Therefore, without analysis there is no understanding of the essence of processes, and without understanding there is no movement forward. In this regard, we can say that for the analysis of high-potential complex processes, we can replace the method of mathematical analysis built on a variable function of a number, replacing it with a function of a constant component of the number. This is the only way to analyze and model not only highly dynamic processes, but also multidirectional and multidynamic along these vectors. That is, it is possible to combine the interconnectedness of the processes occurring both in the flow material and in its kinetic component, in the distribution of the potential difference upon the expiration of the hydro-gas-dynamic flow over the surfaces, and hence their degree of ionization, etc., etc.
    2. Pcorda38
      Pcorda38 6 September 2015 14: 45 New
      very true, the Isotta-Fraschini engine is better on the beautiful SS-4.

      However, Italy has resorted to motorjet, why not produce jet turbines.

  2. gridasov
    gridasov 6 September 2015 11: 34 New
    And then I read about the "new heart of Russian aviation: like super engines." Nothing new that could speak of real progress. Replacing some materials with others, like an experimental site. Algorithms for organizing a process in a gas turbine plant are old and completely undeveloped for understanding, so that we can talk about development as such.
  3. Dan Slav
    Dan Slav 6 September 2015 11: 34 New
    Interesting. Article plus.
    The plane is beautiful for that time.
    They know how to do beautiful things in Italy.
    1. gridasov
      gridasov 6 September 2015 11: 39 New
      The old axiom that “everything that flies beautifully, well” needs to be replaced. “Everything should fly on perfect engines !!! (and that’s beautiful and that’s not beautiful and that in fact shouldn’t fly, but that’s also very beautiful.)"
      1. cdrt
        cdrt 6 September 2015 13: 31 New
        Quote: gridasov
        “Everything should fly on perfect engines !!! (and that’s beautiful and that’s not beautiful and that in fact shouldn’t fly, but that’s also very beautiful.)"

        Americans joke that aerodynamics is for those who do not have powerful engines :-)))
        1. gridasov
          gridasov 6 September 2015 13: 47 New
          But since the screw or propeller, and, accordingly, any turbine, has a critical correspondence after which the application of power does not increase the rotation speed, and therefore it is impossible to increase the performance of hydro-gas dynamic, then we can talk about engine power quite relatively. So the physical process itself has critical parameters of its development. This also means that you can change the algorithms of this process. But all stubbornly do not want to not only understand this, but also limit themselves in development. Aerodynamics is for low-grade flights and flows. Then everything is different.
        2. Pcorda38
          Pcorda38 6 September 2015 14: 31 New
          no, non furono quelle capre di americani a dire il detto, ma Enzo Ferrari parlando di F.1 ... "L'aerodinamica è per quelli che non sanno costruire il motore".

          Congratulations to the site ... just great! good
          1. gridasov
            gridasov 6 September 2015 15: 11 New
            We are talking about the possibility of not just creating a new engine, but the ability to completely analyze all the processes in the thermodynamic cycle and only after that get the opportunity to create the F1 engine, but the main thing is the engine for working on super-sound and in rockets as a principle for the operation of a turbo-fuel supercharger.
            1. WUA 518
              WUA 518 6 September 2015 16: 58 New
              Who is interested in:
              1. gridasov
                gridasov 6 September 2015 17: 19 New
                All errors are there. Ie the lack of understanding of that. What is a hydro-gas-dynamic flow and how to form it for the efficient operation of the propulsion device.
                1. Wasiliy1985
                  Wasiliy1985 9 September 2015 22: 46 New
                  HE FLY! Despite the mistakes - he flew!
                  TsAGI, by the way, already existed in "this country", but in Italy at the same time there was no "Central Aero Hydrodynamic Institute" ..
                  “Damned Stalin!” (C) reached out - not?
                  Even then..
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