On the History of Domestic Jet Propulsion Technology

(P. N. Lebedev’s Engine Designs for Aeronautics)

A. R. Serdyukov

Among the still far from fully studied scientific legacy of the great Russian physicist P. N. Lebedev, preserved in various archives, one can find numerous notes by the scientist both on problems of physics and on problems of technology. In particular, the sketches of designs for jet engines published in the present article, made by P. N. Lebedev in 1892,*) relate to problems of jet propulsion technology.

As we have established, P. N. Lebedev considered two types of engines intended for flying machines. The diagram of the engine of the first type is shown in Fig. 1, and the diagram of the second in Fig. 2.

The operating principle of the engine of the first type is as follows. From reservoir \(K\), an easily inflammable liquid**) under high pressure passes through tube \(A\) to opening \(a\), forming, together with \(b\), an injector device. The jet of atomized liquid issuing from opening \(a\) will draw air into the combustion chamber***). The mixture formed in the chamber of atomized easily inflammable liquid and air (the oxidizer) is ignited by the incandescent walls of the chamber and produces high pressure. After the explosion, the gases rush out through the opening and form a second injector, drawing in through \(CC\) a new portion of air (oxidizer), and so on. Finally, the gases issuing through \(DD\) produce a reactive action, and the entire system is set in motion.

*) Archive of the Academy of Sciences of the USSR, fond 293, op. 1, No. 90, pp. 176–185.
**) In P. N. Lebedev’s opinion, such a liquid could be petroleum.
***) In P. N. Lebedev’s opinion, it would have been advantageous to heat the air before mixing it with the atomized liquid.

Fig. 1. Diagram of P. N. Lebedev’s air-jet engine.

Fig. 2. Diagram of P. N. Lebedev’s pulsed-action turbine engine.

It is easy to discern in this type of jet engine the presence of elements of the modern so-called pulsed air-breathing jet engine, used on flying bombs*).

The idea of the engine design considered by P. N. Lebedev appears more fully in the schemes of the so-called injector jet engines**). Constructive schemes of such an engine were proposed by the American Lake in 1909 and by the Frenchman Melo in 1920. In essence, P. N. Lebedev’s scheme anticipates the designs of Lake and Melo.

The second type of engine, considered by P. N. Lebedev in the same year 1892 and likewise intended for aircraft based on the use of sliding planes (wings), is a turbine operating analogously to an internal-combustion engine. P. N. Lebedev called this type of engine an “explosive turbine.” P. N. Lebedev describes its principle of operation as follows (see Fig. 2): “the detonating mixture***) explodes, reaches enormous pressure (and at high pressure only turbines are suitable and advantageous) and sets the turbine into rotational motion....” This action will continue “until the pressure is all expended and a negative pressure is obtained; then the valve opens again, admitting more detonating mixture, again an explosion—a new impulse, and so on. Such a turbine acts by explosions, not continuously. Of course, one may devise turbines which automatically take care of the most advantageous composition of the mixture. By using petroleum, one can conveniently fly with such an engine.

“The most convenient for such turbines would be the use of two liquids which, when mixed, give an explosive mixture****).

“It is possible to arrange an automatic transmission of the explosion after every 10–15 revolutions of the turbine.”

Further, P. N. Lebedev points out the particular features of the construction of the individual turbine parts, which must meet the operating conditions of the engine. In concluding the description of this type of engine, P. N. Lebedev wrote: “If they find that it will be rational to fly heavier than air, then will it not also be rational to swim in water heavier than water? It goes without saying that such swimming will be possible and bene—

*) Flying bombs with jet engines of this type were used during the Second World War by the German fascists for raids on London.

In P. N. Lebedev’s design there is lacking only the valve closing the entrance to the engine during the flash, which is necessary to prevent the reverse ejection of the combustible mixture through the inlet opening.

**) See, for example, A. E. Primenko, Jet Engines, Their Development and Application, pp. 103–105, Oborongiz, 1947.

***) Here by detonating mixture P. N. understood a mixture of petroleum or gasoline vapors with air.

****) The components of such a mixture, in P. N.’s opinion, could be nitric acid and glycerin.

reasonable only at enormous speeds; with suitable turbine engines this would not even present significant difficulties.”

Without entering into a consideration of the technical merits and shortcomings of the designs of engines for flying machines published here, let us point first of all to the fact that P. N. Lebedev, then still a young physicist, for the first time looked with a scientist’s eyes at what had seemed fantasy, and discerned the future of the types of engines for aviation that he considered in 1892. The ideas, profound in content, that lay at the basis of P. N. Lebedev’s designs found their realization in the engines of modern jet technology. It may be stated with confidence that the scheme of an air-jet engine considered by P. N. Lebedev anticipated designs realized in our own days. The original idea underlying the scheme of the “explosive turbine” finds a partial reflection in so-called turbojet engines with gas turbines of pulsating action.

One cannot fail to note also the fact that a physicist took up the solution of such problems as the creation of types of engines for aviation—one whose interests, judging by his scientific works, lay far from the problems of technology. However, this trait was characteristic of progressive Russian scientists, who strove to embody their knowledge in tangible assistance to their people, to their science and technology. And only the conditions of pre-revolutionary Russia hindered the realization of these noble aspirations.