One of the main difficulties in combating forest fires with conventional water-based methods is the difficult topography and the fact that there are usually no accessible roads to bring firefighting techniques closer to the fire site. Today, a large number of scientific teams are working on the topic of extinguishing the edge of a forest fire with soil. The aim of the study is to increase the efficiency of forest fire prevention and extinguishing by ground-throwing machines by removing the upper combustible layer of forest soil, the formation of a loosened soil shaft from the mineralized layers of forest soil and throwing soil into the edge of a forest ground fire. The paper briefly describes the technical means for extinguishing forest fires using soil. The analysis of the structures of soil-throwing machines has been carried out. The promising directions for improving the technology and working bodies of fire-fighting ground launchers are described, the advantages and disadvantages of its designs are revealed, and ways of further improvement are outlined. A promising design of a strip-laying soil gun with a hydraulic drive of working bodies for preventing and extinguishing forest fires is presented. A distinctive feature of the developed design of the strip-laying soil launcher is the use of an auger to remove the upper fire-hazardous cover, consisting of plant residues, and cut spherical discs to improve the quality of loosening the soil shaft. As a result of the conducted studies of the working process of the strip-laying machine, it was found that the share of the soil covers with combustible materials in the soil flow decreased from 40 to 7%, and the quality of soil shaft loosening increased by 17%, due to which the average distance of soil ejection increased from 10 to 15 m and the power consumption of the rotor-thrower is reduced from 12 to 10 kW.

To date, the problem of forest fires does not lose its relevance. New technical means are being developed to prevent and eliminate forest fires. The article describes laboratory tests of a forest fire soil-throwing machine with the function of fire-break maker. To conduct experiments on the study and analysis of the process of throwing soil with a forest fire soil-throwing machine with the function of fire-break maker, a laboratory installation was developed and manufactured with the ability to change a large number of adjustment parameters with the ability to work in the soil channel of the MF and MD laboratory. The program of experimental studies included the study of the process of throwing soil with a throwing cutter equipped with 6, 4 or 3 blades, when working together with spherical disks with a diameter of 440 mm. The experimental studies were carried out as follows. Initially, by turning on the hydraulic drive, the cutter-thrower of the experimental sample of forest fire soil-throwing machine with the function of fire-break maker was put into rotation. The speed of the cutter-thrower was 500 rpm. Then the attachment of the traction and energy trolley was put into operation, which lowered the cutter-thrower to contact with the soil. The trolley was set in motion at a constant speed of 0.28 m/s and covered a distance of 10 m in 36 to 38 s, taking into account acceleration and deceleration. The depth of the cutter-thrower was 0.15 m. At the end of the movement, it was braked and the hydraulic motor was turned off, which set the cutter-thrower in motion. The pressure characteristics of the working fluid, as well as the dynamic characteristics of the operation of the device, were taken using the strain gauge station ZetLab (ZET 058). According to the results of processing the experimental data, it was determined that it is rational to use 6 blades to equip the design of the cutter-thrower. The optimal value of the angle γ of their installation is -10º.

The search for energy efficient tillage technologies and the creation of more advanced machines while reducing the cost of the final product are one of the priority goals. One step in the development of tillage implements is to develop a theoretical basis. In this case, mathematical or simulation modeling is used, but part of the work carried out in the laboratory and in the field is an integral part of the research structure. Of great importance in testing forestry equipment are dynamometer methods, which consist in measuring the forces transmitted from the engine to the machine or acting on the working bodies and parts of the machines. This is especially true for forest implements that interact not only directly with soils, but also with roots, branches, stumps and other components of forest soils. The article is presented in the form of an analysis of the structures of dynamometric installations used to conduct research on tillage equipment. Also given are the designs of installations used for research of combined machines with active working bodies, such as a forest fire engine. Particular attention is paid to structures for volumetric dynamometry (2D and 3D).

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The paper presents the results of studies of the working processes of screw working bodies in various industries. Studies of the technological parameters of screw working bodies during the removal of the ground cover with combustible plant residues have been insufficiently carried out. A new design of a forest fire machine is proposed, including screw working bodies for removing the ground cover with combustible plant residues, cut-out discs, for the formation of a soil shaft in front of the rotor-thrower, with an adjustable guide casing with the ability to change the directional flow of soil. Working bodies of the forest fire soil-throwing machine are described by a system of differential equations of the translational, rotational movements of the auger working body and the equation of the flow rates of the working fluid. The Cauchy problem is considered on the interval t∈ (t_0; t_end). Original system is reduced to a system of recurrence relations due to its nonlinearity, replacing the derivatives of the desired functions with their finite analogs. This system is unresolved with respect to the senior member. One can apply the method of splitting the system into systems in subspaces of decreasing dimensions and solve the system in these subspaces due to the Fredholm property of the operator coefficient in front of the leading term. The analytical solution of the mathematical model for removing the ground cover by auger working bodies of a forest fire soil-throwing machine when laying fire strips and extinguishing grassland forest fires makes it possible to determine the kinematic and dynamic parameters of the auger working bodies using the final formulas. Simulation modeling of the screw working process was carried out on a virtual laboratory bench. The dependences of the dynamic characteristics of the auger working bodies when overcoming obstacles have been obtained. It was found that the maximum average value of the torque is observed when overcoming an obstacle with a height of 100 mm and the rotation speed of the working body of 400 rpm is 1468.49 N ∙ m, at which its performance is not impaired.