寻求速度新突破的舰载直升机

舰载直升机作为直升机的一支,有着许多其他飞行器所不具备的垂直起降、空中悬停,全向机动等诸多优势,如何在确保其基本性能的基础上进一步提高飞行速度,这是直升机设计师正在研究的课题,也是困扰全球航空界许多年的难题。近年来,由于几种附加推力型直升机的出现,几种倾转旋翼机相继投入使用,旋翼锁启型试验机的试飞成功,以及高速圆盘旋翼机设计方案的推出,使航空界又看到了希望和光明。     

打造国产直升机腾飞之翼——记航空工业昌飞旋翼分厂工艺员程翔

正直升机对旋翼系统要求极为严苛,旋翼技术也成为衡量直升机先进程度的关键指标,更被视为直升机行业花钱也买不到的核心机密。让六片每片120公斤重、9米长的直升机旋翼,在动平衡试验台以每分钟100到215转速,旋转画一个直径18米的圆圈,这个圆旋翼的翼尖高度差只允许正负5毫米,力矩差只     

双旋翼直升机旋翼的微多普勒特性分析

目前,国内外对双旋翼直升机的微多普勒特性研究相对还很少。建立了直升机旋翼回波的微多普勒模型,并基于该模型,分别计算了共轴式、横列式、纵列式以及交叉式双旋翼直升机的微多普勒。研究结果表明,不同种类的双旋翼直升机旋翼的微多普勒特性不同,通过对双旋翼直升机旋翼的微多普勒进行分析,可以对双旋翼直升机进行初步分类,为下一步双旋翼直升机的微多普勒识别提供了参考和借鉴。     

十年心如钢,千里快哉风——记旋翼技术骨干熊绍海

<正>年仅33岁的熊绍海,在中航工业直升机设计研究所旋翼传动室从事旋翼研制工作岗位上度过了11个年头,尾桨叶旋翼动力学组的每一项工作,他无一没有涉猎,通过扎实的实践历练和理论钻研,他已然从青涩的设计员成长为旋翼技术领域的骨干。直升机设计系统是充满风险与挑战的,这是一项要求近乎苛刻、极其复杂而又艰难的工作。旋翼系统是直升机的核心,它每一项技术的进步,都标志着直升机关键技术     

独具特色的倾转旋翼机技术

倾转旋翼机是一种性能独特的旋翼飞行器。它既具有传统旋翼机(即直升机)垂直起降和空中悬停的能力,在旋翼倾转后、巡航飞行时又酷似螺旋桨动力的固定翼飞机。正是由于突破了传统旋翼机的思维定势,才产生了采用崭新设计原理的倾转旋翼机,使直升机技术得到了革命性、跨越式的发展。倾转旋翼机融合了直升机与固定翼飞机的优点,是一种军民两用的高技术产品。它既具有垂直起降能力,能像直升机一样,执行兵员/装备突击运输、战斗搜     

自适应旋翼技术——让直升机减少噪声和振动

直升机具有独特的飞行性能——依靠旋翼在空中悬停、在狭小空间内垂直起降,使其成为重要的空中运输和作战平台。目前,在旋翼设计中还存在一些空气动力学问题,对直升机飞行产生不利影响。这主要表现在,直升机在起飞、降落和空中悬停过程中,旋翼气动噪声很大;在巡航飞行中,旋翼振动比较剧烈。上述问题大大影响了直升机的乘坐舒适性,降低了直升机的使用寿命;对于军用直升机,还会削弱其隐蔽性,降低行动的突然性和战场生存力。     

榴弹搭载伞降子弹减旋特性分析

针对榴弹搭载伞降子弹减旋翼片的结构特点,分析了其所受力矩,建立了伞降子弹在减速减旋阶段运动微分方程,仿真计算得出了在此阶段子弹的转速-时间曲线,计算结果和实弹试验均表明减旋翼片能使子弹的转速在较短的时间内由几百转/s降至零,从而使子弹达到稳定工作状态,说明减旋翼片能够满足伞降子弹的减旋要求。最后,分析了不同展长和开伞点不同存速对减旋翼片减旋性能影响。     

旋翼-机身组合体对机载导弹的气动干扰

直升机对机载导弹的气动特性和初始弹道的影响,对于改进导弹发射技术和载机的安全具有重要意义.对时间滗步进自由尾迹模型进行改进,建立了一种能快速收敛的悬停旋翼自由尾迹模型,并与机身面元模型耦合成旋翼/机身组合体气动干扰模型.发展了一种旋翼/机身组合体干扰条件下导弹气动特性的工程计算方法,并对某型空空导弹的气动特性和初始弹道进行了数值模拟.结果表明,导弹在最初几米内气动力系数变化十分剧烈,说明直升机确实对导弹具有很强的干扰作用.最后对结果作了简要分析,指出了直升机下洗气流对导弹的气动干扰规律.     

多姿多彩的直升机旋翼

说到直升机,人们会记得孩子们爱玩的“竹蜻蜒”,用一根竹竿和几片竹片做成,使劲一搓,便“嗖”的一声蹿向空中。人类就是受它的启蒙发明了直升机。 直升机的英文名为Helicopter,意为“旋转的翼”。这一名称表明了旋翼是直升机的象征。于是,设计师们在直升机旋翼上绞尽脑汁,经过多年的追求和探索,产生了形态各异的直升机旋翼。     

卡—52“短吻鳄”战斗直升机

卡—52直升机是在卡—50的基础上发展起来的一种双座型全天候战斗直升机。该型机参加了1996年莫斯科航空展览,倍受瞩目。据称,卡—52将在2000年初开始装备俄罗斯军队。 卡—52直升机旋翼直径14.50米,机长15.96米,最大起飞重量11400公斤,最大平飞速度310公里/小时,最大垂直爬升率(高度     

Helping hands: civil–military cooperation and Italy's military operation abroad

In the Post-Bipolar Era the growing complexity of the military operations requires a new approach for the resolution of international crises. Since the end of the Cold War, peace support operations (PSO) have become the mainstay and principal occupation of most Western armies. At the same time, Italy has been one of the most important actors in such an area. The article focuses on the cooperation between military and civil components (a process called CIMIC) as a key variable in the Italian PSOs. We will analyse in detail the main lessons learned from past military interventions as well as the general context in which new tendencies are taking place. The maintaining of a minimum security frame becomes essential to fulfil activities ‘collateral’ to the mission: reconstructing services and infrastructure, food distribution, water and medication, law and order, de-mining, training of local forces, and supporting local institutions. These are the main tasks to obtain thrust and support from the population.     

Terrorism,insurgency, kidnapping,and security in Africa's energy sector

Energy continues to serve as the bedrock of modern economies and the main driver of modern society. For Africa, the production and supply of energy resources such as crude oil, natural gas, uranium, coal, biomass, biofuels and other renewables are an important source of employment, rents, taxes, royalties and profits. This sector brings in several tens of billions of dollars of revenue annually. The production and delivery of such resources, however, depend on critical infrastructures such as pipelines, refineries, processing plants, terminals, rigs, electrical energy pylons, substations, pump stations, vessels, and tankers. These infrastructures have been attacked by terrorists, insurgents, vandals and saboteurs, all of whom see them as targets against which to register their grievances and extract concessions from the state. This paper is a chronological account of some of the documented incidents of terrorism, insurgency, kidnapping, destruction, sabotage, and human casualties suffered in the oil and gas sectors in Africa between 1999 and 2012. It is based on data extracted from the databases of the RAND Database of World Terrorism Incidents and the University of Maryland's Global Terrorism Database (GTD).     

Tacit support for terrorism: The rapprochement between the USSR and Palestinian guerrilla organizations following the 1967 war

This article demonstrates the inconsistent and wavering Soviet attitude towards national liberation movements in general and the Palestinian organizations in particular. Until the late 1960s, the Soviets viewed these organizations with suspicion, hesitating to engage in political dialogue with them. However, in the 1970s, political and military events in the region, as well as modifications in the Kremlin's Cold War strategies, led to a general shift towards the Middle East in Soviet foreign policy. Soviet leaders showed increased willingness to provide certain Palestinian organizations with arms with which to conduct terrorist activities against Israeli, pro-Israeli, Jewish and Western targets. The article explores the complex relations between Palestinian organizations and the USSR in the field of international terror. The study also exposes and analyzes the nature and content of Soviet–Palestinian arms dialogues and transactions. It provides clear evidence that Soviet policymakers and other luminaries were fully informed of, and sometimes directly involved in, these transactions and dialogues at the highest levels.     

A1 Qaeda and the radical Islamic challenge to western strategy

The September 11 global crisis prompted by the attacks on the World Trade Center and the Pentagon raises major questions concerning the nature and trajectory of terrorism in the post-Cold War global order. Hitherto, terrorism has been largely debated by analysts at the level of nation states. Terrorist and insurgent movements have also been largely anchored in nationalist and ethnic power bases even when they have sought to mobilise a transnational ideological appeal on religious or class grounds. There have been a few exceptions to this pattern such as the alliance between the German Baader-Meinhof group and the Japanese Red Army Faction, but even such international alliances as this did not, until at least the 1980s, presage anything like a global terrorist network necessitating a global strategic response. This study examines terrorism and global strategic responses.     

Reviews

Douglas S. Derrer, We Are All the Target: A Handbook of Terrorism Avoidance and Hostage Survival. Annapolis, MD: US Naval Institute Press, 1992. Pp. x+135, notes, index. $14.95. ISBN 01–55750–150–5

Ian Knight, Zulu: Isandlwana and Rorke's Drift, 22–23 January 1879. London: Windrow & Greene, 1992. Pp.136, 150 illus., incl 8 colour plates, maps, biblio. £35. ISBN 1–872004–23–7

Ian Knight, By the Orders of the Great White Queen: Campaigning in Zululand through the Eyes of the British Soldiers, 1879. London: Greenhill Books and Novato: Presidio Press, 1992. Pp. 272, 17 illus., 1 map. £18.95. ISBN 1–85367–122–3

Manfried Rauchensteiner and Erwin A. Schmidl (eds.), Formen des Krieges: vom Mittelalter zum ‘Low‐intensity’ Conflict’. Graz : Verlag Styria, 1991. Pp.208. DM35. ISBN 3–22–12139–7

Harold J. Kearsley, Maritime Power and the Twenty‐First Century. Dartmouth: Dartmouth Publishing Company, Limited, 1992. Pp.xv + 203, 13 diagrams, index. £32.50. ISBN 1–85521–288–9     

Helping hands: external support for the KNU insurgency in Burma

This article analyses to what extent the Burmese KNU insurgency made use of external support from states, refugees, and diasporas. Based on extensive fieldwork it is concluded that support from neighbouring states and refugees has for years kept the Karen rebellion alive. Western countries perceived forms of resistance to the illegitimate Burmese regime as just and have therefore played a crucial role in the continuation of conflict in Karen State. It is important that policymakers and donors as well as executing organizations continue to reflect critically on the way they exercise their work.     

基于GTST-DMLD-ESD的装备RMS建模仿真

装备的RMS是装备的重要设计参数,是影响战备完好和保障能力的关键因素.引入GTST-DMLD作为主要建模工具,建立起装备系统的RMS描述模型,以ESD为补充和扩展,对维修过程进行建模.并以GTST-DMLD-ESD模型作为装备RMS仿真的核心,对装备RMS仿真模型的总体框架进行了研究,并对各模块进行了较为详细的探讨.     

Panjwai: a tale of two COINs in Afghanistan

The US Army has two approaches to counterinsurgency operations in Afghanistan. One is hard, or combat-focused, and the other is soft, or development-focused. This study examines two US Army task forces deployed to Panjwai District, Afghanistan from 2012 to 2013. CTF 4-9 and 1-38 offer a meaningful comparison because they pursued these contrasting approaches among the same population and against the same enemy at the same time and place. The study compares each unit’s approach and finds that neither approach was successful absent the other. The article concludes by recommending further research into combining the approaches at the operational level.