Annotation: The paper presents the experiment-calculated data on hydraulic parameters of ring intake device in different operation modes. The method of their calculation is proposed taking into account limit deviations of influencing factors. Satisfactory convergence of calculated and experiment data is shown.

Annotation: Amid acute problems that arise in the field of rocket and space technology, mechanical engineering, and other fields and require a workable engineering solution, the problem of prediction and prevention of the unpredicted collapse of the structural members of the structures subjected to loading is considered. Prediction of the load-carrying capacity and residual life of the space frames during the long-term operation is based on the analysis of the stress and strain state, using readings from the strain and displacement pickups installed in the most loaded zones. In this case the yield strength of the structural material or the fatigue strength of the material may be considered as the criterion of the maximum load. At the same time the loss of stability of the compressed structural members used in the load-carrying thin-walled structures are among the potentially dangerous failure modes. In these cases such failure occurs unexpectedly without any visible signs of change in the initial geometry. Application of the adequate diagnostic techniques and methods of prediction of the maximum loads under compression conditions will make it possible to avoid the structural failures. In this case an assembly under test may be used for other purposes. To perform static strength testing, the rocket and space companies use costly compartments of as-built dimension. Therefore, keeping compartments safe solves an important problem of saving financial costs for hardware production. Nowadays this problem is particularly acute when ground testing the new technology prototypes.

Annotation: The article dwells on the problem of enhancement of durability for the mechanical rubber articles, which is directly related to the enhance of rubber resistance to various types of heat aging. Heat resistance during compression is most important for rubbers used for seals of various types: rings, collars, armored collars, gaskets for aviation and rocket technology hardware. Stress relaxation and the accumulation of relative residual deformation of rubbers, caused by the kinetic rearrangement of chemical bonds, are extremely sensitive to the influence of high temperatures. The main cause of the defects is the loss of elastic properties of the seals because of the accelerated heat aging of the nitrile group under conditions of long-term exposure to elevated temperatures in conditions of hot climate. The results of accelerated climatic testing of specimens of mechanical rubber articles, as well as the results of climatic endurance testing of the units for the period simulating 20-year service life are specified, and the main types of defects which result in the loss of performance properties of the mechanical rubber articles are as follows: great (up to 100%) residual deformation of intersections, cracking, loss of elasticity. The warranty life of fuel system units, made of ИРП-1078 nitrile rubber, does not exceed 12 years. Replacing the existing rubbers with rubbers created on the basis of more heat-bearing rubbers is the most promising way to improve the performance properties of the mechanical rubber articles under the high temperatures. The new D2301 rubber is based on fluorosiloxane rubber. It provides high thermal stability and, especially, the ability to maintain high performance properties for a long time under the simultaneous impact of hostile environment and high temperatures. The results of climatic endurance testing of fuel system units, equipped with rubber articles made of D2301 rubber, fully justify the increase of the specified service life of the specified units from 12 to 16 years. It is recommended to introduce D2301 rubber into the effective normative documentation and continue studies in order to extend the nomenclature of mechanical rubber articles made of D2301 rubber to provide the reliable sealing of units during the service life of 16 years or longer.

Annotation: Separation of the spent LV stages is one of the important problems of the rocket technology, which requires the comprehensive analysis of different types of systems, evaluation of their parameters and structural layouts. Basic requirements are specified that need to be taken into account when engineering the separation system: reliable and safe separation, minimal losses in payload capability, keeping sufficient distance between the stages at the moment of the propulsion system start. Detailed classification of their types («cold», «warm», «hot», «cold-launched» separation) is given and their technical substance with advantages and drawbacks is described. Certain types of «cold» and «warm» separation of the spent stages of such rockets as Dnepr, Zenit, Antares, Falcon-9 with different operating principle are introduced – braking with the spent stage and pushing apart two stages. Brief characteristics of these systems are given, based on the gas-reactive nozzle thrust, braking with solid-propellant rocket engines, separating with spring or pneumatic pushers. Development of the separation system for the advanced Cyclone-4M ILV is taken as an example and design sequence of stage separation is suggested: determination of the necessary separation velocity and capability of the separation units, determination of the number of active units, calculation of design and energy parameters of the separation units, analysis of the obtained results followed by the selection of the separation system. Use of empirical dependences is shown, based on the great scope of experimental and theoretical activities in the process of design, functional testing and flight operation of similar systems in such rockets as Cyclone, Dnepr and Zenit. According to the comparative analysis results, pneumatic separation system to separate Cyclone-4M Stages 1 and 2 was selected as the most effective one. Its basic characteristics, composition, overall view and configuration are specified. Stated materials are of methodological nature and can be used to engineer the separation systems for LV stages, payload fairings, spacecraft etc.

Annotation: The article gives the analysis results for the servo drives dynamics, obtained from the theoretical calculations and during the development testing of the high power electric drives. Theoretical research was conducted, using the complete mathematical model of the servo drive, which included the equations of the control signal shaping path, electric motor, reducer and load. The equations of the control signal shaping network include only the characteristics of the compensating element in the assumption that all other delays in the transformation path are minimized. The electric motor equations are assumed in the classical form, taking into account the influence of the following main parameters on the motor dynamics: inductance and stator winding resistance, torque and armature reaction coefficients and rotor moment of inertia. Interaction of the motor with the multimass system of the reducer and load is presented in the form of force interaction of two masses – a reduced mass of the rotor and mass of the load through the certain equivalent rigidity of the kinematic chain. To describe the effect of gap in the kinematic connection the special computational trick, which considerably simplifies its mathematical description, is used. Efficiency of the reducer is presented in the form of the internal friction, proportional to the transmitted force. Calculation results with the application of the given mathematical model match well with the results of the full-scale testing of different specimens of servo drives, which makes it possible to use it for the development of new servomechanisms, as well as for the correct flight simulation when testing the aircraft control systems. In particular, based on the frequency response calculations of the closed circuit with the application of the given mathematical model, it is possible to define optimal parameters of the correcting circuit. Reaction on the step action with the various values of circular amplification coefficient in the circuit gives complete information on the stability regions of the closed circuit and influence of various drive parameters on these regions. Based on the conducted theoretical and experimental studies, the basic conclusions and recommendations were obtained and presented, accounting and implementation of which will provide high dynamic characteristics of the newly designed servo drives.

Annotation: Specialized design office for liquid engines was established on July 22, 1958 to develop engines and propulsion systems, powered by liquid propellants to be installed on the combat missile systems and integrated launch vehicles (LV), developed by Yuzhnoye SDO. Moreover, liquid engines design office was assigned with manufacturing and testing of the main rocket engines, developed by NPO Energomash and to be installed on Yuzhnoye-developed launch vehicles. Over the past 66 years Yuzhnoye SDO has developed more than 40 liquid rocket engines (LRE) of various purpose, designed both to gas-generator cycle and to staged combustion cycle. Seventeen of them were commercially produced by Yuzhmash PA and installed on launch vehicles. Nowadays Yuzhnoye propulsion experts keep working on development of the advanced liquid rocket engines powered both by cryogenic and hypergolic propellants, which satisfy the majority of launch service market demands. Within the framework of extensive cooperation with foreign space companies, on a contract basis, Yuzhnoye propulsion experts are working on the design and development testing of the liquid rocket engines, as well as their components. The accumulated vast experience in the development of liquid rocket engines nowadays enables high scientific and technical level in the creation of up-to-date engines, demanded in the world market. Significant steps in this area have been made by the experts from the Yuzhnoye propulsion division and then subsequent manufacture and delivery by Yuzhmash PA of the engine intended for the European rocket Vega Stage 4; and designing the individual components for the engines with thrusts ranging from 500 kgf to 200 tf ordered by foreign customers. This article provides the review of current and scheduled activities of the Yuzhnoye SDO to develop the liquid rocket engines within the thrust ranges from ~ 40 kgf to ~ 500 tf.

Annotation: One of the main types of arming of modern tactical and short-range missiles are cassette warheads based on nonguided blast-fragmentation submunitions that are widely used to kill group targets. The fullscale testing (flight tests) is an integral part of their creation. In the process of flight tests of tactical and shortrange missiles with cassette warheads, the safety issues are topical. Based on the capabilities of existing test ranges, it is planned to conduct such tests for the tactical and short-range missiles, being under development in Ukraine, in the Black sea water area where the cassette warheads with nonguided blastfragmentation submunitions (or their equivalents) will pose major hazard for ships. In the paper, two mathematical models are proposed to assess probability of killing (risk) a ship that may be present in the impact area of submunitions (submunitions equivalents) of cassette warhead. The first model was constructed in the assumption that the coverage area of cassette warhead and group dispersion of submunitions are known. Such model may be used to determine safety in the initial phases of cassette warheads development. The second model assumes that the configuration of cassette warhead and the scheme of submunitions firing were finalized, and accordingly, the nominal impact points of submunitions and their group and ind ividual dispersion are considered to be known. Practical application of both models requires the use of numerical procedures.

Annotation: Launch vehicle lift-off is one of the most critical phases of the whole mission requiring special technical solutions to ensure trouble-free and reliable launch. A source of increased risk is the intense thermal and pressure impact of rocket propulsion jet on launch complex elements and on rocket itself. The most accurate parameters of this impact can be obtained during bench tests, which are necessary to confirm the operability of the structure, as well as to clarify the parameters and configuration of the equipment and systems of complex. However, full-scale testing is expensive and significantly increases the development time of the complex. Therefore, a numerical simulation of processes is quite helpful in the design of launch complexes. The presented work contains simulation of liquid rocket engine combustion products jet flowing into the gas duct at the rocket lift-off, taking into account the following input data: the parameters of propulsion system, geometric parameters of launch complex elements, propulsion systems nozzles and gas duct. A three-dimensional geometric model of the launch complex, including rocket and gasduct, was constructed. The thermodynamic parameters of gas in the engine nozzle were verified using NASA CEA code and ANSYS Fluent. When simulating a multicomponent jet, the equations of conservation of mass, energy, and motion were solved taking into account chemical kinetics. The three-dimensional problem was solved in ANSYS Fluent in steady-state approach, using Pressure-based solver and RANS k-omega SST turbulence model. The calculation results are the gas-dynamic and thermodynamic parameters of jets, as well as distribution of gas-dynamic parameters at nozzle exit, in flow and in boundary layer at gas duct surface. The methodology applied in this work makes it possible to qualitatively evaluate the gas-dynamic effect of combustion products jets on gas duct for subsequent optimization of its design.

Annotation: Being a final executive element of rocket control systems, a hydraulic actuator is at the same time the main source of various non-linear dependencies in rocket dynamic design whose availability dramatically com plicates theoretical analysis of their dynamics and control systems synthesis. The required accuracy and complexity of mathematical models of hydraulic servo mechanisms are different for different design phases of guided rockets. The paper deals with the simplest models of hydraulic servo actuators intended to calculate rocket controllability and to define requirements to response and power characteristics of the actuators. To calculate the rocket stability regions and to evaluate own stability of servo actuators, a linearized mathematical model of hydraulic servo actuator is used that takes into account the most important parameters having impact on stability of the servo actuator itself and on that of the rocket: hardness of working fluid, stiffness of elastic suspension of the actuator and control element, slope of mechanical characteristic of the actuator in the area of small control signals, which, as full mathematical model analysis showed, is conditioned only by dimensions of initial axial clearances of slide’s throats. The full mathematical model constructed based on accurate calculations of the balance of fluid flow rate through the slide’s throats allows, as early as at designing phase, determining the values of most important static and dynamic characteristics of a future hydraulic actuator, selecting optimal characteristics of slides based on specified degree of stability and response of servo actuator and conducting final modeling of rocket flight on the integrated control system test benches without using real actuators and loading stands. It is correct and universal for all phases of rockets and their control systems designing and testing. Using this mathematical model, the powerful actuators of a line of intercontinental ballistic missiles with swinging reentry vehicle and the main engines actuators of Zenit launch vehicle first stage were developed. The results of their testing separately and in rockets practically fully comply with the data of theoretical calculations.

Annotation: The effective documents in the field of metrological support require evaluating measurement uncertainty during measuring instrumentation calibration. In Ukraine, there is no regulated procedure of uncertainty calculation during measuring instrumentation calibration, which causes the necessity of developing such procedure. This article proposes the measurement uncertainty calculation procedure during measuring instrumentation calibration, according to which the following calculations shall be made: a) of standard uncertainty of A type for corrected observation results obtained during calibration; b) of standard uncertainties of B type caused by error or uncertainty of working standard applied, calculation discreteness or calibrated measuring instrument division value, variation of calibrated measuring instrument indications; c) of total standard measurement uncertainty; d) of augmented measurement uncertainty. As an example, the results of calculation of augmented measurement uncertainty during calibration are presented: – for 795M107B vibrometer in complete set with AC102-1A accelerometer; – for alternating voltage measurement channel of a measuring and computing complex of MIC type; – for a manometer of MT type. The obtained results of measurement uncertainty calculation are presented in the form of tables of measurement uncertainty budget, which shall be entered in the measuring instrument calibration certificate together with the observation results obtained during calibration. The proposed uncertainty calculation procedure is applicable for the given types of measuring instruments whose calibration is performed by method of direct measurement of known measurement values represented or controlled by working standards.