Launch Technology Research Articles

Firing range optimization of a 155mm uni-modular charge howitzer by ETC technology

Electrothermal-chemical (ETC) launch technology can accurately control and enhance the ignition and combustion of solid propellants to improve the consistency and accuracy of ballistics. In this paper, a calculation model including the transient burning rate formula and six-degree-of-freedom rigid body trajectory equation is established to simulate both interior and exterior ballistics processes for a 155mm uni-modular charge howitzer. The simulation results show that the muzzle velocities are optimized via the ETC technology. The 155mm uni-modular charge ETC howitzer can effectively obtain the minimum range, increase the range overlap and maximum range, and improve the ballistic stability and consistency.

Research on 100kJ pulsed power module for electromagnetic launch

With the development of the electromagnetic launch (EML) technology, the requirement of the pulsed power supply is increasing. Capacitor-based pulsed power supply usually consists of several hundred kilojoule level pulsed power modules (PPM) in parallel. The PPM for EML system requires the capability of continuous working ability, high energy storage density and high peak current. A 100kJ compact PPM with rated operational voltage 10kV was designed, the output peak current was about 90kA, and the continuous working ability was 6 times per minute. The design and selection of main components in the module were simulated. At last, the PPM was used in the testing of the coil gun. It provides transient pulse current test platform and technical support for the subsequent construction of megajoule level pulsed power supply.

Impact envelope simulation for kinetic kill missile intercepting short range high speed target

For direct impact kinetic kill missile, it not only need high precision guidance technology, but also related to the size, collision position, angle and speed of missile and target. Due to the limitations of the real projectile interception test technology, the cost and the launching technology of ground hypervelocity collision experiment, the simulation modeling and analysis are the main means to carry out the research of direct collision kinetic technology and the evaluation of interception effect. In this paper, aiming at the kinetic energy interception of short range high-speed target under the constraints of collision angle and miss distance, the terminal impact envelope is simulated, and the relative position of missile and target on the collision probability is analyzed.

The summary of missile electromagnetic catapult technology

Missile electromagnetic catapult technology is the important application of electromagnetic launch technology in the field of missile and a great breakthrough compared with tradition catapult technology. Inducing main components and technological advantages of missile electromagnetic catapult system. Sketching technical characteristics of three missile electromagnetic launcher including coil launch, DC motor and rail launch. Introducing current development situation of missile electromagnetic catapult technology in home and abroad. Carding key technologies which restrict practicability of missile electromagnetic catapult technology. Expecting prospects for development of missile electromagnetic catapult technology.

Factors Affecting the Compression and Energy Absorption Properties of Small-Sized Thin-Walled Metal Tubes

To solve the problem of the effective cushioning of fast-moving mechanical components in small ring-shaped spaces, the factors affecting the compression and energy absorption properties of small-sized hollow metal tubes were studied. Simulation models were constructed to analyse the influences of tube diameter, wall thickness, relative position, and number of stacked components on the compression and energy absorption properties. The correctness of the simulation method and its output were verified by experiments, which proved the effectiveness of compression and energy absorption properties of small-sized thin-walled metal tubes. The research provides support for the application of metal tube buffers in armament launch technology and engineering practice.

Effectiveness Evaluation of Aircraft Electromagnetic Launch System Based on RIMER

Electromagnetic launching technology is one of the important application technologies in aerospace field in the future. It will change the way of rocket launching and even be applied to aerospace kinetic energy weapon system. Aiming at the characteristics of various bottom indicators, uncertain information probability and expert participation in the effectiveness evaluation system of aircraft electromagnetic ejection system, based on the index hierarchy model, the method of RIMER(rule-base inference methodology using the evidential reasoning) is used to evaluate the effectiveness, which provides some reference for the design and development of aircraft electromagnetic launching system.

Analytical Model for a Brushless Air-Core Compensated Pulse Alternator

The air-core compensated pulse alternator (CPA) as a high power pulsed power supply, has broad applications in many fields such as electromagnetic launch technology, electromagnetic gun, laser weapons, and so on. The structure, design, control method, and performance characteristics of the air-core CPA are quite different from those of the traditional electric machines. Most of the available literature on the air-core CPA mainly focuses on theoretical and simulation research, and the research methods primarily made use of the finite element method and the multiphysics coupling analysis. High calculation precision is the main advantage of the finite element method and its complex modeling and prolonged computation time are its downsides. If the parameters of the electric machine changes, the finite element model have to be rebuilt. In this article, the author introduces a universal calculation method of the winding inductance of the air-core CPA using a brushless air-core CPA as an example. The article establishes the machine’s analytical model and also calculates the self and the mutual inductance of the windings according to the machine design parameters. The analyzation of its no-load and discharge characteristics by use of the machine’s analytical model is also demonstrated. Finally, the article also compares the calculation results of the analytical method with those of the finite element method. The comparative results verify the correctness of the inductance calculation method and the machine’s analytical model.

Effect of injection pressure on the plasma-liquid interaction in a stepped-wall liquid chamber

The electrothermal chemical launch is a new concept hypervelocity launch technology that the propellant is ignited by high-temperature plasma. Understanding the heat and mass transfer mechanism between plasma and liquid and choosing a reasonable injection pressure is crucial for a reliable launch. Experimental and numerical studies are carried on to investigate the plasma-liquid interaction mechanism, as well as the effect of injection pressures ranging from 2 MPa to 8 MPa. As plasma expands in a stepped-wall chamber, the plasma jet's axial penetration speed is decreasing and the surface area is increasing linearly. The plasma front surface varies from an arc shape to a cone shape, and the necking phenomenon forms near the step. Vortexes generated in the interaction flow field are divided into four categories. There is intensive pressure variation near the nozzle and a pressure peak in the pressure decrease region. Besides, increasing the injection pressure enhances the plasma expansion ability and promotes the phenomena which increase the plasma surface. However, increasing the injection pressure aggravates the flow field instability. Formulas for estimating the plasma jet's axial penetration distance and surface area growth rate are summarized for choosing a reasonable injection pressure.

Research on low recoil launch technology of small UAV with small arms mounted on it based on floating principle

The small unmanned aerial vehicles (SUAV) which is mounted with small arms have both the accurate firing ability of small arms, and the mobility, flexibility and concealment of SUAV. In order to reduce the influence of recoil on SUAV, we put forward a low recoil launch method based on floating principle. Take a certain type of rifle as a study object, we have established a virtual prototype model. Through simulation and firing test, the recoil reduction effect is verified. This method provides a feasible and effective technical way for small unmanned platform to mount weapons in service.

Appraisal of Rapid-Fire Electromagnetic Launch Effects on Ceramic Targets

With the current developments in electromagnetic launch technology, railguns have become more suitable for multiple applications. This paper explores the delivery of a rapid succession (several per second) of projectiles to a 100 cm2 ceramic target. We test whether a series of impacts on a target will cause more damage than a single impact of equivalent energy. This premise is based on the fact that the target is damaged at the first impact and is thus weakened when subjected to subsequent impacts. We use a series of physical experiments to evaluate this hypothesis, and to assess the magnitude of the effect. The launch system is the SR\3-60 railgun, developed by the French-German Research Institute of Saint-Louis, which comprises three pairs of rails mounted in a hexagonal geometry. Each pair of rails is connected to a 150 kJ capacitive power supply with 2 m acceleration length. The SR\3-60 can be used to generate very flexible multi-hit impact sequences. Tungsten-tipped projectiles were launched against sintered alumina (Al2O3) targets. In the first set of experiments, the damage caused by a single projectile is compared to that caused by a pair of smaller projectiles, each having a fraction of the weight of individual projectile and fired at a greater velocity, so that a pair of impacts carries the same kinetic energy as an individual one. This was also extended to three projectiles. High-speed video imagery was deployed to capture fracture development in the target. Comparisons are performed at a range of subsonic velocities.

A Novel Structure of Augmented Railgun Using Multilayer Magnets and Sabots

A novel augmented railgun using multilayer magnets and sabots is proposed in this paper, in which the rails have dc constant currents. Using dc constant currents for the rails generates the constant acceleration for the projectile. The augmentation with multilayer permanent magnets increases the length of passing current, which improves the railgun efficiency. Furthermore, the proposed railgun does not require the high power supplies because each sabot carries only low current. In addition, the iron structure has been located at the top and bottom of the whole structure to produce a homogeneous magnetic field. Accurate analytical expressions have been derived for the Lorentz force and the velocity of the proposed structure in this paper. The railgun structure has been simulated in Maxwell software for various rail currents, and the analytical results have good agreement with simulation results. The amplitude of the Lorentz force in the z-direction has been calculated for various sabot materials to investigate the effect of the sabot materials on the performance of the railgun. Our results indicate that the velocity of the projectile can achieve to 300 m/s for the projectile mass of 2 kg in our proposed railgun. This makes the railgun a good candidate for the heavy projectiles in the launcher technology.

Optimal Dynamic Product Development and Launch for a Network of Customers

Network products such as mobile apps and computer games are of paramount importance, as these products constitute a large value in today’s economy. Motivated by this observation, the paper “Optimal Dynamic Product Development and Launch for a Network of Customers” considers a firm that dynamically chooses its effort to develop a product for a network of customers represented by a connected graph. The technology of the product evolves as a stochastic process that depends on the firm’s dynamic efforts over time. In addition to dynamically choosing its development effort, the firm chooses when to launch or abandon the product. If the firm launches the product, the firm also chooses a selling price, a promotional price, and a target customer to offer the promotion to. Once the target customer adopts the product, the product diffuses over the customer network based on the topology of the graph and the selling price. The paper provides the explicit solution of the firm’s jointly optimal development, launch, and post-launch strategies for any connected network, and introduces metrics that allow ordering customer networks with respect to the firm’s optimal expected discounted profit, launch technology, and consumer surplus.

Guest Editorial Special Issue on Electromagnetic Launchers-2018

The editors of this special issue of the IEEE Transactions on Plasma Science (TPS) are pleased to present an issue that documents a wide range of topics being actively studied within the field of electromagnetic launch (EML) technology. Many of the articles contributed to this issue are from participants of the 19th IEEE EML Symposium held on June 18–22, 2018 in Saint Louis, France ( https://www.isl.eu/eml2018/ ). The EML has a long history of serving the EML community as a gathering forum for the presentation and discussion of these fields as the most relevant research topics.

Research Progress of Electromagnetic Launch Technology

As a natural result of the electrified integration and electrical energy revolution, the electromagnetic launch (EML) technology will be inevitably used for future launch missions. This paper has summarized research focuses in this field according to the published papers on EML in China during the past decade and mainly introduced the current research and progress in several key technologies, including launcher, integrated launch package, high-power high-density supply, and overall control/maintenance. Some common pressing problems are pointed out to provide direction for the application of EML technology in engineering and many other fields, such as launcher life, miniaturization of power supply, and improvement of energy availability.

Design method of surface-to-air missiles using the object-oriented approach and electronic launch technology

Design method of surface-to-air missiles using the object-oriented approach and electronic launch technology

Analysis of the magnetic field and electromagnetic force of a non-striking weft insertion system for super broad-width looms, based on an electromagnetic launcher

Weft insertion based on electromagnetic launch technology is a novel and very promising approach for super broad-width (6–12 m) (SBW) looms. There are considerable challenges involved in designing such a system, including analyzing the electromagnetic field while incorporating the effect of a clip weft device, and accurately calculating the electromagnetic and motion parameters of the weft insertion mechanism. In this study, an electromagnetic launch, non-striking weft insertion method for an SBW loom is proposed. The electromagnetic field is analyzed with the finite element method and includes the effect of a clip weft device. Simulation of the motion, analysis of the maximum flight speed of the clip weft device and the work done by electromagnetic force are presented. We also describe an experimental model for electromagnetic launch weft insertion and calculate the electromagnetic force required for weft insertion, using analytical methods and numerical finite element methods. Comparison of the results with measured values shows that this electromagnetic launch weft insertion system has good flexibility. In addition, the weft insertion speed required for different width looms can be obtained by changing the current of the coil or the coil stage number of the launching system.

Low cost small-satellite access to space using hybrid rocket propulsion

Increased demand for smallsat launch capabilities drives on the search for low-cost launch vehicles. Hybrid rocket technology has been pushed forward in the recent years and is now ready to meet the demand of this low-cost rocket development. With intrinsic safety and reliability the development and production cost of hybrid rocket engines can be a small fraction of bi-liquid propulsion systems. At the German Aerospace Center DLR a hybrid rocket engine is developed in cooperation with the German start-up company HyImpulse Technologies GmbH in order to advance launcher technology in Germany. A concept for a mini-launcher has been designed by HyImpulse and the development of a 75 kN (SL) hybrid rocket engine is on-going with a test campaign foreseen in 2019. This engine will be the largest hybrid rocket engine ever tested in Europe. It takes advantage of the long development and research history of paraffin-based hybrid rockets at the DLR Lampoldshausen. Since 2010 paraffin-based fuels have been analyzed and improved. Additives have been found to greatly improve the mechanical properties of the paraffin solid fuel. At the same time the regression rate has been modulated to adapt the fuel for use in launcher applications. The concept of the HyImpulse mini-launcher includes eleven engines of this type, which will result in large scale serial production for the foreseen launch rate of twelve launches per year. This further reduces production costs of the hybrid rocket engine. The advantage of paraffin-based fuel lies in the simple geometry of the grain caused by the high regression rate. A cylindrical fuel grain will have a much lower manufacturing cost compared to classical wagon wheel fuel grains with HTPB. Hybrid launchers are often used within pressure fed propulsion systems, but in order to increase the payload of the launcher, this is replaced with a gas generator and turbo pump driven propulsion system for this launcher concept.

Expansion Characteristics of a Plasma Jet in the Stepped-Wall Chamber Filled with Water

The interaction mechanism between the plasma and liquid is a key problem for the electrothermal chemical launch technology. To investigate this problem, a simulated experiment for the expansion process of a plasma jet in the working fluid is carried on. Based on this experiment, a two-dimensional axisymmetric unsteady theoretical model is established to reveal the plasma-liquid interaction flow field pattern. The results show that a typical Taylor cavity forms as the plasma jet expands in liquid. The induction effect of the stepped-wall structure enhances the radial expansion of the plasma jet. An arc-shaped pressure wave is generated at the front of the plasma jet and then evolves into the plane wave. A high-pressure area forms at the head of the plasma jet and then moves downstream. There is a strong plasma-liquid turbulent mixing at the interface, especially near the steps and the nozzle exit area.

Electromagnetic launching technology and boron at Moon for Space

Gelecek yıllarda, ay yerinde keşfedildiğinde, aydan uzaya malzeme nakliyesi yeteneklerinin geliştirilmesi planlanmaktadır. Uzay araçlarının yakıt ikmali için gerekli oksijen gibi ay malların yörüngedeki depolara taşınaması sağlanacaktır. Genel olarak aydan malzeme nakliyesi söz konusu olduğunda EMFS (Elektromanyetik Fırlatma Sistemi) teknolojisinin, yakın gelecekteki üstünlükleri çok iyi açıklanabilir. EMFS’nin kimyasal fırlatma sistemine göre, yüksek kapasiteli taşıma, yüksek güvenlik ve çevresel sürdürülebilirlik ile düşük bakım maliyetleri ve yüksek verimlilik gibi çeşitli avantajları bulunmaktadır. Sunulan ön konseptin geliştirilmesi ve bu tür bir sistemle dağıtımının fizibilite ve net faydası ile ilgili, yüksek yük taşıma kapasitesine sahip oluşu EMFS’yi desteklemektedir. EMFS halen sürdürülen bir çalışmadır ve özellikle donanım geliştirme aşamasında dikkate alınması gereken birçok zorlukları bulunmaktadır. Bu çalışmada Yüksek Sıcaklık Süperiletken (HTSC) MgB2 gibi malzemeler, ana güç üretimi, veriyolu çalışması, endüktif enerji depolama, devre açma anahtarları, başlatıcı bobinler ve yükler dahil, birçok EMFS bileşenleri için yaygın olarak kullanılan uygulamalardır.

Current Situation and Trend of Air-to-air Missile Launch Technology

Current Situation and Trend of Air-to-air Missile Launch Technology