Launcher Model Research Articles

Theoretical modeling and analysis of the launching process in an electromagnetic coil launcher

The rapid increase of space activities has led to an urgent problem of space debris. Active debris removal based on flexible nets is promising in the control of space debris. Here the application of electromagnetic launch in the deployment of flexible net is considered. A lumped-parameter electromechanical model of the coil launcher is developed with emphasis on the analysis of the magnetic field involved. Analytical solution to the magnetostaic problem is given based on eigen-expansions on decomposed domains. Dynamic behavior of the iron slug is then computed and analyzed with optimal initial position of the iron slug found. Influence of the capacitance of the super-capacitor upon the launch performance is also investigated. Results are discussed and future directions of investigations are provided.

Instantaneous Pressure Reconstruction From PIV In Compressible Launcher Environments

Modern launcher configurations, often characterized by a larger diameter in the payload fairing than the rest of the launch vehicle (hammerhead configuration), face significant challenges during transonic operations, given their susceptibility to flow separation and intense pressure fluctuations. This experimental study aims to reconstruct pressure from PIV under transonic conditions using Taylor's hypothesis. The focus is on the ESA VEGA-E hammerhead launcher model, investigated in the transonic regime at Ma=0.8 and at α=0°. Initially, the methodology of the pressure reconstruction algorithm is described and the validity of Taylor's hypothesis is established through validation with numerical data. Subsequently, the experimental data are first used to provide a general characterization of the flow phenomenon, highlighting key features such as an oscillating shockwave, separated and reattached flows. Later, the reconstruction of pressure from velocity data is compared to unsteady pressure transducer data, for instantaneous, average and standard deviation values, obtaining a very good agreement (ΔCpAvg~0.01-0.02 and ΔCpStd~0.02). The experimental set-up is also designed to showcase the impact of neglecting the out-of-plane velocity component on pressure reconstruction, showing comparable data for CpAvg, while larger discrepancies in terms of CpStd in particular in the separated area region.

Modelling the Wall Pressure Fluctuations on the VEGA-C Launcher in Supersonic Conditions

The prediction of pressure fluctuations generated over the external surface of aerospace launchers during the atmospheric flight remains a challenging task due to the complexity of the geometry and the effects of compressibility at high supersonic Mach numbers. An experimental database is here analysed to the scope of providing a procedure to model and predict the relevant statistics of the wall pressure fluctuations generated by a supersonic flow overflowing the VEGA-C Launcher Vehicle. Data have been obtained in an extensive Wind Tunnel test campaign carried out in the trisonic wind tunnel of the National Institute for Aerospace Research (INCAS) in Bucharest. Wall-mounted pressure transducers allowed for the computation of the pressure Auto- and Cross-spectra over the fourth (the payload region) and third stages of the launcher model. Coherence functions are modelled through exponential-like analytical functions following the approaches usually adopted in canonical boundary layer flows, whereas the auto-spectra models are based on polynomial fits. The approach adopted for the achievement of proper non-dimensional quantities as well as the procedure implemented for the full-scale extrapolation is presented and discussed.

Launch Dynamic Simulation of a Compressed-Air Launcher for Fire Suppression

This paper focuses on improving fire suppression performance through the use of compressed-air launching technology. A launch dynamics calculation model of a compressed-air launcher is presented, developed using VC++ programming, to simulate the acceleration process of a fire-extinguishing bomb in a barrel. By analyzing the influences of various structural and initial parameters on interior ballistics variations, the effectiveness of the calculation model and program in accurately simulating the launching process is demonstrated. The calculation results indicate that the bore pressure follows a similar trend to that of traditional gunpowder launching. Additionally, it is found that specific structural parameters, such as nozzle diameter and gas cylinder volume, have a direct impact on interior ballistics variations. Notably, the nozzle diameter positively affects the peak pressure, muzzle velocity, gas transfer efficiency, and launch efficiency. To ensure an optimal launch effect and efficiency, the nozzle diameter should be selected to be more than half of the launcher caliber. Similarly, the gas cylinder volume positively influences the peak pressure and muzzle velocity while negatively affecting the gas transfer efficiency and launch efficiency. Furthermore, the initial pressure in the gas cylinder exhibits a positive linear relationship with both the peak pressure and muzzle velocity but a negative linear relationship with the gas transfer efficiency and launch efficiency. The loading position minimally impacts the peak pressure and muzzle velocity but slightly enhances the gas transfer efficiency and launch efficiency. Finally, it is observed that launch angles do not affect the interior ballistic process. The research findings provide valuable theoretical guidance for determining the working parameters of compressed-air accelerated fire-extinguishing bombs.

VR-Supported Analysis of UAV—Magnetic Launcher’s Cart System

The subject of the research is a model of a magnetic launcher, which is an innovative alternative to commercially occurring unmanned aircraft launchers (UAV). As the take-off is an energy-demanding phase of the flight; therefore, abandoning the power supply of the UAV during this phase significantly affects increasing the potential range and duration of UAV flight. The magnetic launcher offers the significant advantage of minimizing friction between the starting cart and the launcher, resulting in the higher energy efficiency of the system. Research conducted so far has shown that the possibility of accelerating the aircraft on the longer runway offered by the launcher reduces aircraft overloads occurring during take-off. As a result, the launcher, aircraft, and onboard equipment are much safer. This paper presents the system’s mathematical modeling and numerical simulation results for micro-class UAV take-off and landing using the analyzed magnetic launcher. The computer program for analyzing system dynamics was implemented in the MATLAB environment. Simulation results were visualized graphically and as animations in Virtual Reality. The VR application was implemented in Unity and ran on VR goggles Oculus Quest2. The simulations carried out show that—in the absence of control—an important factor reducing the takeoff distance and affecting the aircraft load is the adoption of a non-zero takeoff thrust of the UAV. The initial pitch angle also has a significant impact on the takeoff process. With an increase in this parameter, the length of the takeoff distance decreases and the lift-off speed decreases, but too much pitch angle may result in the aircraft descending in the first moments of flight, which could lead to a collision with the launch rails.

Research on Transient Contact Characteristics of the Hyperbolic Rail Augmented Quadrupole Launcher

The contact surface between the armature and rails of a railgun system is unique for its high-speed sliding and current conduction, which greatly affects the performance of the launcher. In order to study the armature–rail contact characteristics of the electromagnetic railgun, this article simulates the initial contact characteristics, the conducting contact characteristics, the electromagnetic characteristics, and the temperature closely coupled to the contact characteristics based on a hyperbolic rail augmented launcher model. The influencing factors of the contact characteristics are analyzed and compared with the nonaugmented railgun with the same structural configuration, and the evaluation indices of the contact characteristics are established. The research results show that the contact characteristics of the railgun are affected by the electromagnetic force, which changes rapidly with time, which in turn affects the electromagnetic and temperature characteristics of the railgun. This launcher structure can maintain good contact conditions during launching. This study is a preliminary exploration of the contact characteristics of the hyperbolic rail augmented quadrupole launcher, making an improvement to its structural design.

Performance Evaluation for Launcher Testing Vehicle

The paper’s purpose is to present a calculus model for a testing vehicle that can be used to validate guidance, navigation and control systems for reusable launchers in all flight phases. The technical solution is based on a throttleable engine with thrust vectoring control and a reaction control system (RCS) used for roll. For calculus, we will develop a nonlinear model with six degrees of freedom, based on quaternion, extended with nonlinear equations that use pulse modulation in order to control roll. In order to synthesize the controller, we also develop a linear model similar to the launcher model. The paper analyzes two basic scenarios, first with the ascending and the descending flight phases and the second having a horizontal flight interleaved between ascending and descending flight phases, both scenarios being specific for reusable launchers. Based on these scenarios, the paper evaluates some performances of the proposed vehicle, namely flight envelope and guidance accuracy.

Analysis of Electromagnetic Characteristics of Copper-Steel Composite Quadrupole Rail.

The ablation and wear of the four-rail electromagnetic launcher during the working process will aggravate the damage of the armature and rail, and greatly affect the service life of the launcher. To effectively alleviate rail damage, this paper applies the copper-steel composite rail to the four-rail electromagnetic launcher and proposes a new four-rail electromagnetic launcher. Based on the quadrupole magnetic field theory, the physical model of the new four-rail electromagnetic launcher is established, and the electromagnetic characteristics of the ordinary and new launchers are compared and analyzed using the finite element method. On this basis, the influence of composite layer parameters on the electromagnetic characteristics of copper-steel composite quadrupole rail is explored. The study found that the new four-rail electromagnetic launcher can provide a better launch magnetic field environment for smart loads, and the current distribution of the armature and the rail contact surface is more uniform, which can effectively improve the contact condition between the armature and the rail. The composite layer parameters of copper-based composite rail will have a certain impact on electromagnetic characteristics, and copper-steel composite rail of appropriate proportions can be selected according to different needs. The model proposed in this paper has a certain degree of scientificity and rationality.

Research on Vehicle-Mounted Electromagnetic Ejection Remote Fire Extinguishing System

This article first introduces the characteristics and disadvantages of traditional remote fire extinguishing technology and proposes a remote fire extinguishing system based on electromagnetic ejection. Based on the finite element analysis method and the grid matrix method, a seven-segment electromagnetic launcher model is designed. As the initial energy source, the capacitor can accelerate a 10 kg fire extinguishing bomb to 113 m/s with a range of 2 km. The results show that the electromagnetic catapult designed in this study can meet the needs of fire extinguishing bombs. This paper also designs the overall structure of the vehicle electromagnetic catapult remote fire extinguishing system, discusses its role in the field of firefighting, and prospects the future work.

Research on Electromechanical Model of Multistage Synchronous Induction Launcher

Based on current filament method, the model of multistage synchronous induction coil launcher is established. The model considers the coupling effects between the drive coils, between the drive coils and each piece of armature, and between each piece of armature. In addition, in the launching process, the effect of drive coil and armature resistance and inductance generated by skin effect, magnetoresistive effect and current heating effect are taken into consideration. Finally, the 5‐stage synchronous induction coil launcher is designed and manufactured. Dynamic launch experiments are designed to verify the correctness of the model. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Experiences in engineering design training at Samara University

This paper aims to share experience gained by Samara National Research University in training students in engineering degree programme “Manned and Unmanned Spacecraft and Space Systems”. Core items of engineering degree curricula are projects because they basically form practical experience of future design engineers. Main items of the course project “Calculation of main parameters and generation of land remote sensing satellites conceptual design based on regard to required efficiency indices” are discussed. These include acquisition and processing of statistical data on space systems and satellites; determination of satellite orbit parameters; determination of massdimensional characteristics of spacecraft on-board systems and construction; formation of on-board systems; spacecraft construction models and assembly model; choice of launcher and spacehead model development. The activity is supported by appropriate training materials and software.

Research on Arc Suppression Parameter Matching of Augmented Electromagnetic Launcher

In order to effectively suppress the muzzle arc, an augmented electromagnetic launcher (EML) model with arc suppression has been established. Then, the model was validated by experiments with and without arc suppression. Finally, the matching between the arc suppression parameters (charging voltage, trigger delay, and installation position) and the main circuit was investigated. The results show that the electromagnetic force formed by the arc suppression circuit is the braking force before the armature passes the arc suppression installation position, and then becomes the driving force after the armature passes the arc suppression installation position. In general, the arc suppression trigger delay and the charging voltage should be reasonably matched to achieve that most of the current in the muzzle is removed by the arc suppression circuit when the armature is released. Besides, in the design of EML, the installation position of arc suppression should be fully considered in combination with its influence on arc suppression effect and muzzle velocity.

Structural Design and Dynamics Simulation Analysis of A Certain Type of Co-frame Launcher

To study the dynamic response of a certain type of co-frame launcher during launch, this article uses the 3D modeling software Pro/E to import the model into Adams from the perspective of launch dynamics. the launch dynamics model of the shared-frame launcher is established. We apply the ejection thrust of the two types of missiles to the corresponding ejection devices and measure and collect the dynamic parameters of the cartridge system. The simulation results show that the dynamic parameters of the A and B missiles are in line with the available overload design requirements. The B-type missiles are superior to the A-type missiles in terms of ballistic orbit contact force and ejection attitude.

Numerical Simulation of Laminate-Containment Launcher Based on the Electromagnetic–Mechanical Coupled Model

The laminate-containment structure is a kind of high-efficiency containment structure, which reduces the eddy current and increases the velocity of the armature. However, the research on the whole launching process of the laminate-containment launcher is rarely mentioned. In order to realize the numerical simulation of the whole launching process of the laminate-containment launcher, a simplified model of the laminate-containment launcher is established, and the electromagnetic–mechanical coupling calculation of the model is carried out by using the finite-element analysis (FEA). In the process of calculation, the pulse power source (PPS) program and electromagnetic field co-simulation are used to realize the field-circuit coupling calculation of the launching process. The movement of the armature during the launching process is realized by an embedded interior ballistic program. This calculation method provides a way to deeply understand the launching process of the laminate-containment launcher.

Study on impact resistance of composite rocket launcher

Abstract The transient impact load during the launch of a rocket at sea threatens the safety of the launcher and the deck structure of the launch platform. In view of the impact resistance of the offshore rocket launcher system, this paper takes the real-scale rocket launcher system as the research object and establishes the analysis model of the fiber-reinforced composite rocket launcher based on the finite element method. Then, we explore the factors of the thickness by finite element simulation method and the angle and the position of IM7 fiber-reinforced composite, which influence the impact resistance property of the rocket launcher. The results show that the fiber-reinforced composite rocket launcher can effectively reduce the impact response of the structure and improve the impact resistance of the structure. The best laying scheme is to lay four layers of IM7 fiber material on both sides of the panels of the fixed bracket and the webs of the erector, respectively, with a single layer thickness of 0.75 mm and a laying angle of [90°/∓45°/90°].

Evaluation of the SteamVR Motion Tracking System with a Custom-Made Tracker

The paper presents the research of the SteamVR tracker developed for a man-portable air-defence training system. The tests were carried out in laboratory conditions, with the tracker placed on the launcher model along with elements ensuring the faithful reproduction of operational conditions. During the measurements, the static tracker was moved and rotated in a working area. The range of translations and rotations corresponded to the typical requirements of a shooting simulator application. The results containing the registered position and orientation values were plotted on 3D charts which showed the tracker’s operation. Further analyses determined the values of the systematic and random errors for measurements of the SteamVR system operating with a custom-made tracker. The obtained results with random errors of 0.15 mm and 0.008° for position and orientation, respectively, proved the high precision of the measurements.

Optimization Calculation of Single Stage Coil Launcher Based on Prediction Model

At present, the optimization design method of electromagnetic coil launcher mainly includes of manual trial and error method and intelligent algorithm. The former has low optimization efficiency and poor effect, while the latter can obtain optimization results, but the calculation time is longer. In order to improve the calculation efficiency and obtain the global optimal solution of the coil launcher, the optimization process of the coil launcher must be improved. In this article, a genetic algorithm based on a predictive model is adopted. By using the output of the predictive model as the optimization target and constraint target of the optimization algorithm, it avoids calling the full model of the coil launcher during the optimization process and effectively reduces the calculation time. The orthogonal test method and the current filament method are used to establish 49 sets of orthogonal sample data of the single-stage coil launcher. The optimal armature speed of the coil launcher obtained in the orthogonal test is 59.81 m/s; the support vector regression (SVR) prediction model is obtained by training on the orthogonal test results, and the prediction error of the test data is 0.39%; the genetic algorithm based on the prediction model is used to optimize the single-stage coil launcher. The calculation result shows that, without constraints, the peak speed of the armature is 60.17 m/s. After the temperature constraint is added, the peak speed of the armature is 59.86 m/s.

Research on energy conversion efficiency of the reconfigurable reconnection electromagnetic launcher

Improving energy conversion efficiency (ECE) is of vital importance for the synchronous induction electromagnetic launcher (SIEL). For the launch process that the mass of payload is constant, there are many methods about the structural optimization of SIEL have been proposed to maximize the ECE. However, one optimized SIEL may be difficult to achieve same excellent launch effect when launching payloads of different masses. To realize the different launch purposes based on one SIEL device, this paper proposes a reconfigurable reconnection electromagnetic launcher (RREL) to effectively adjust the ECEs of payloads with different masses, the operable characteristics of RREL are described clearly through an example of a four-stage launcher model. Assume that the peak pulse current of the driving coils is 15 kA and the peak acceleration overload of the payload is 15 k-gees, the ECE characteristics of payload with the mass varing from 1 kg to 9 kg are simulated and analyzed through the finite-element method (FEM). The simulation results show that the payloads with different masses can achieve high ECEs through adjusting the reconfigurable operation states of the drive coil assemblies. For example, to obtain the best ECE of 1 kg payload, the switching states of the driving coil assemblies should be in “0 ∖”; When the mass of payload is 4 kg, the switching states of the driving coil assemblies should be in “0 1”; Similarly, the optimal ECE of the 7 kg payload occurs in the switching states of “1 1”. Finally, a small experimental platform is constructed to test. Although there are about 14.7% error exist between the experimental and the simulation results due to the mechanical losses, above technical scheme is feasible and has some reference significance for the development of SIEL design. © 2020 Elsevier Science. All rights reserved.

Investigation of the base flow of a generic space launcher with dual-bell nozzle

The typical afterbody flow of a space launcher is characterized by a strong interaction of the engine’s exhaust jet and the separated shear layer emerging from the main body. This interaction is further complicated by strong changes in the spatial and temporal behavior of the afterbody flow during the atmospheric ascent of a launcher. Theoretically, a dual-bell nozzle not only allows for a gain in payload compared to standard single-bell nozzles, but also it alters the wake flow topology due to the two nozzle modes. To predict the benefits as well as the additional risks, the afterbody flow of a generic space launcher model equipped with a cold-flow dual-bell nozzle is investigated in detail. The flow was analyzed for sub-, trans- and supersonic Mach numbers ranging from 0.3 to 2.9 for a variety of nozzle pressure ratios. Particle image velocimetry measurements and schlieren measurements with high repetition rate were performed to determine the dynamics of the separated shear layer, the nozzle jet and their interaction. It is shown that the reattachment length of the base flow decreases with increasing nozzle pressure ratio. Furthermore, the nozzle pressure ratio at which the dual-bell nozzle switches from sea-level mode to altitude mode is reduced by 15% with high subsonic outer flow and by as much as 65% for an outer flow at a Mach number of 1.6. Even for a constant nozzle pressure ratio, the nozzle flow topology depends on the Mach number of the outer flow.

Research on Armature Recovery of a Coil Launcher

At present, the boost payload of electromagnetic coil launcher mainly adopts integrated launching mode; that is, the armature and payload are integrated into a projectile to shoot out of the bore together. There are some problems with this kind of launching form, such as high parasitic mass and low efficiency of payload launching. In this article, a payload projection scheme of armature–load separation launching is proposed. When the armature and payload reach the peak velocity, the armature is separated from the payload by electromagnetic capture force, and the armature can be recovered and reused under certain conditions. A model of five-stage coil launcher is established and the interior trajectory characteristics of armature under the integrated launching and separation launching modes are compared by simulation. It is shown that the mass of armature will exaggerate the launching performance. The armature–load separated launching mode can effectively improve the launching efficiency. Then the armature recovery method is further proposed. The armature velocity is related to many factors such as mass ratio of armature and payload, driving voltage, and turns of the last coil stage. The study proves that under certain conditions, the armature can be recovered, which could improve the safety of launch.