Aerodynamic characteristics of ribbon stabilized grenades
Aerodynamic characteristics of ribbon stabilized grenades
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带状稳定手榴弹的气动特性
DOI：
10.2514/6.2000-270
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
David C. Purinton
中科院分区：
文献类型：
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作者：
L. Auman;C. Dahlke;David C. Purinton
为了确定手榴弹带状稳定器的空气动力特性，进行了一项广泛的试验计划。虽然数据是从垂直和水平风洞试验、自由飞跌落试验和自由飞火炮试验中获得的，但本文仅介绍水平风洞试验的数据。在该试验期间，在90至180英尺/秒的速度范围内获得静态和动态自由偏航数据。试验获得了轴向力、侧向力、偏航力矩和俯仰力矩，而手榴弹是自由偏航的，或静态固定在给定的偏航角。通过对静、动力和力矩的分析表明，带的振荡运动有四种类型。这些类型的介绍，是作为一个功能的带状长度和带状宽度的零偏航阻力。术语：AoA迎角，度。AF轴向力，Ibs。CM俯仰力矩系数，= PM/QSD。CY侧力系数，= SF/QS。CLN偏航力矩系数，= YM/QSD。轴向力系数，= AF/QS。CD阻力系数（源自CU。CL升力系数（从Cy、CAF和Theta得出）D参考长度= 1.515英寸。PM俯仰力矩，in-lbs。S参考面积，平方in.，= nD 2/4。SF侧向力，Ibs。YM偏航力矩，in-lbs。θ偏航角，度。* AIAA专家-航空航天工程师本文被宣布为美国政府的作品，在美国不受版权保护。C.韦恩达尔克 * 大卫C。Purinton* Dynetics，Inc亨茨维尔，AL前锋一项努力已经进行，以减少危险的哑弹率火箭配发手榴弹低于百分之一。作为这项工作的一部分，目前的研究是作为一个低成本的解决方案，这个问题。目标是消除侧面碰撞，这是危险哑弹的最大单一原因。在分配之后，手榴弹经历大的振荡运动，直到带状稳定器被部署。在稳定器展开后，手榴弹的运动迅速衰减并减慢到终端速度。一旦手榴弹达到终端速度，它不应该经历任何超过20度的振荡运动。以往的带式稳定榴弹风洞试验可分为三类。这些是静力和力矩试验、动态“自由偏航”试验和垂直飞行试验。Dahlke“*”提出的静力和力矩数据是利用金字塔天平收集的，以获得手榴弹的轴向力、侧向力和偏航力矩。Dahlket提出的动态“自由偏航”试验”我测量了作为时间函数的手榴弹偏航角，并根据该数据计算出动态导数（CMa，CMq）。仅对静态数据的分析将使分析者相信当前的带状物提供了足够的稳定性。此外，将静态数据结合到6-DOF模拟中无疑将表明，在分配期间施加的手榴弹振荡迅速衰减，并且手榴弹弹道的其余部分处于相对小的攻角。然而，在“自由偏航”试验中取得的数据和在垂直风洞试验中进行的观察表明，情况并非如此。这种差异可能是由于色带动力学。虽然挥舞丝带确实提供了稳定手榴弹身体（和保险引信）所需的阻力，但挥舞丝带也起到了破坏手榴弹稳定的作用。设计一个真正捕捉手榴弹所有飞行动力学的测试的任务目前是不可能的。一个“完美”的测试需要在小型化的
An extensive experimental program has been conducted to determine the aerodynamic characteristics of grenade ribbon stabilizers. While data has been acquired from vertical and horizontal wind tunnel tests, free-flight drop tests, and freeflight gun tests, this paper presents only the data from the horizontal wind tunnel test. During this test, both static and dynamic free-yaw data were obtained at speeds ranging from 90 to 180 feet/second. The test obtained axial force, side force, yawing moment and pitching moment while the grenade was free to yaw, or while statically fixed at a given yaw angle. Analysis of the static and dynamic forces and moments indicates that there are four types of ribbon induced oscillatory motion. These types are presented, as is the zero-yaw drag as a function of ribbon length and ribbon width. NOMENCLATURE Svmbols: AoA Angle-of-attack, degrees. AF Axial force, Ibs. CM Pitching moment coefficient, = PM/QSD. CY Side force coefficient, = SF/QS. CLN Yawing moment coefficient, = YM/QSD. CAF Axial force coefficient, = AF/QS. CD Drag COeffiCient (derived from CU. CAF & Theta) CL Lift COeffiCient (derived from Cy, CAF & Theta) D Reference length, = 1.515 inches. PM Pitching moment, in-lbs. S Reference area, sq. in., = nD2/4. SF Side force, Ibs. YM Yawing moment, in-lbs. Theta Yaw-angle, degrees. * AIAA Member-Aerospace Engineer This paper is declared a work of the U.S. Government and is not subject to copyright protection in the United States. C. Wayne Dahlke* David C. Purinton* Dynetics, Inc Huntsville, AL FORWARD An effort has been undertaken to reduce the hazardous dud rate of rocket-dispensed grenades to less than 1 percent. As a part of this effort, the current study was initiated as a low cost solution to this problem. The objective being to eliminate side impact, the largest single cause of hazardous duds. Following dispense the grenades experience large oscillatory motion until the ribbon stabilizer is deployed. After the stabilizer is deployed, the grenade motion quickly damps out and slows to terminal velocity. Once the grenade has reached terminal velocity it should not experience any oscillatory motion in excess of 20 degrees. Previous wind tunnel tests of ribbon stabilized grenades may be classified into three types of tests. These are static force and moment tests, dynamic “free-yaw” tests, and vertical flight tests. Static force and moment data presented by Dahlke”‘*’ were collected utilizing a pyramidal balance to obtain the grenade axial force, side force andyawing moment. Dynamic “free-yaw’ tests presented by Dahlket” I measured the grenades yaw angle as a function of time and from that data the dynamic derivatives (CMa, CMq) were calculated. Analysis of the static data alone would lead the analyst to believe that the current ribbon provides adequate stability. Furthermore, incorporation of the static data into a 6-DOF simulation would no doubt indicate that grenade oscillations imparted during dispense quickly damp out and the remainder of the grenade trajectory is at relatively small angles-of-attack. However, data taken during the “free-yaw” tests and observations made during the vertical wind tunnel tests indicate that this is not the case. This discrepancy may be attributed to the ribbon dynamics. While the flapping ribbon does provide the drag needed to stabilize the grenade body (and arm the fuze), the flapping ribbon also acts to destabilize the grenade. The task of designing a test that truly captures all the flight dynamics of the grenade is not currently possible. A “perfect” test would require a breakthrough in a miniaturized