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.

Comments

[fa2998]

The power plant is a dead-end branch. Judging by the 2 motors, each one is supplied with fuel, and each has its own efficiency and mass. range and price. And won in speed (difficult to knock down). The Japanese did not have enough time. Article plus!

[Rus2012]

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.

[Rus2012]

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 ...

[gridasov]

It is worth understanding. that thermodynamic processes in turbines are complex. However, the approaches for calculations are exclusively "standardized", which is for low-potential, that for high-potential. And even there is no such division as methods for analyzing these processes. Therefore, there are objective limits to the fact that it is possible to accurately simulate the processes and installations themselves, and even more so as promising. Therefore, without analysis, there is no understanding of the essence of the processes, and without understanding there is no movement forward. In this regard, we can say that for the analysis of high-potential complex processes, it is possible to replace the method of mathematical analysis of a number built on a variable function, replacing it with a function of the constant component of the number. This is the only way to analyze and model not only highly dynamic processes, but also multi-vector and multi-dynamic in these vectors. That is, it is possible to combine the interconnectedness of the processes occurring both in the substance of the flow and in its kinetic component, in the distribution of the potential difference during the outflow of a hydrodynamic flow over surfaces, and hence the degree of their ionization, etc.

[Pcorda38]

very true, the Isotta-Fraschini engine is better on the beautiful SS-4.







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

[gridasov]

And then I read about "the new heart of Russian aviation: like super engines." There is nothing new to say about real progress. Replacing some materials with others, like an experimental site. The algorithms for organizing the process in a gas turbine plant are the same and are completely not mastered for understanding, so that we can talk about development as such.

[Dan Slav]

Interesting. Article plus.
The plane is beautiful for that time.
They know how to do beautiful things in Italy.

[gridasov]

The old axiom that "everything that is beautiful flies well" must be replaced. "Everything should fly on perfect engines !!! (both what is beautiful and what is not beautiful and what, in fact, should not fly, but flies and is very beautiful.)"

[cdrt]

Quote: gridasov

"Everything should fly on perfect engines !!! (both what is beautiful and what is not beautiful and what, in fact, should not fly, but also flies very beautifully.)"

Americans joke that aerodynamics is for those who do not have powerful engines :-)))

[gridasov]

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.

[Pcorda38]

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!

[gridasov]

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.

[WUA 518]

Who is interested in: http://avia-simply.ru/motokompressornij-dvigatel/

[gridasov]

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.

[Wasiliy1985]

HE FLY! Despite the mistakes - he flew!
TsAGI, by the way, was already in "this country", but in Italy at the same time there was no "Central Aero Hydrodynamic Institute".
"Damned Stalin!" (C) reached out - didn't he?
Even then..