Showing papers on "Projectile published in 1994"

Laser range finding apparatus

Abstract: A laser range finder that is modular so that it can mounted on different weapon platforms. A pulsed infrared laser beam is reflected off the target. The timed return signal is then used to measure the distance. Another laser, either a visible laser or another infrared laser of differing frequency, is used to place a spot on the intended target. Notch pass optical filters serve to eliminate ambient light interference from the second laser. The range finder using projectile information stored in the unit processes the calculated distance to raise or lower the finder on the weapon. A plurality of weapon platforms and projectile is selected by pressing the desired rubberized keypad. The range finder can be used with a laser detonated projectile that can be detonated when the projectile is over the target. The projectile is fitted with a detector that is sensitive to the frequency of a wide angle laser beam that is attached to the weapon. Using the range obtained by the range finder, the wide angle laser beam is fired when the projectile is in proper position relative to the target.

Angular distribution of ions axially channeled in a very thin crystal: Experimental and theoretical results.

Abstract: We have studied the angular distributions for 6--30-MeV C[sup [ital q]+] ([ital q]=4--6) and 2--9-MeV H[sup +] ions axially channeled in the [001] direction of a thin silicon crystal (1792 and 1900 A). We report highly structured two-dimensional angular distributions that depend sensitively on the projectile's velocity and incident charge state and the target's thickness and azimuthal orientation. Some structure in the angular contour maps is the result of a rainbow effect in axial channeling (i.e., extrema in the classical deflection function). State-to-state charge-state distributions, which are required to interpret the data accurately, have also been measured. All measured angular distributions have been explained via Monte Carlo trajectory calculations using Moliere's approximation to the Thomas-Fermi screening function and a screening length given by target electrons alone. The calculations indicate that all projectile velocity and charge-state effects and the target-thickness effects observed are the result of the projectile's transverse oscillatory motion in the channel. Using this information, we show that swift heavy-ion and proton angular distributions are simply related using a scaling law that depends only on the projectile's velocity and charge-to-mass ratio and on the crystal thickness.

Multifunctional magnetic fuze

Abstract: A multifunctional magnetic fuze is disclosed. The sensor includes an apparatus and method for counting each rotation of a projectile after firing from a weapon. A signal is generated which indicates the rotations of the projectile and a counter counts the turns so that the projectile may detonate at a predetermined nominal number of turns. The turns count may also be used to calculate spin rate and muzzle velocity so that the nominal turns count may be adjusted based on actual velocity. The fuze also may include a timer for counting a time to burst of a projectile. The turns count and/or the times count may be utilized to provide accurate detonation.

Analysis of the temperature rise in the projectile and extended chain polyethylene fiber composite armor during ballistic impact and penetration

Abstract: The ultra-high strength/modulus, extended chain polyethylene fiber (Spectra® fiber) composite has shown great potential as a lightweight armor material with its extraordinary capability of absorbing the kinetic energy of projectiles. But the relatively low melting point of this fiber (-145 o C) has caused concerns regarding the effect of temperature rise during the impact/penetration process on the performance as armor material. In this article, an analysis of temperature rise in projectile and the fiber composite during the impact/penetration process is described

Energy dependence of collective flow of neutrons and protons in 197 Au+ 197 Au collisions

Abstract: We investigate the beam energy dependence of neutron and proton squeeze-out in collisions of197Au+197Au atE/A=400—800 MeV. The azimuthal anisotropy that describes the enhanced emission of mid-rapidity neutrons perpendicular to the reaction plane rises strongly with the transverse momentum of the neutrons. This dependence of the azimuthal anisotropy follows a universal curve — independent of beam energy — if the neutron momenta are measured in fractions of the projectile momentum per mass unit. Analogously, the kinetic energy spectra of mid-rapidity neutrons exhibit a universal behaviour as a function of the kinetic energy of the projectile.

Applications of computational fluid dynamics to the aerodynamics of army projectiles

Abstract: The ability to predict the complete set of aerodynamic performance parameters for projectile configurations is the goal of the computational aerodynamicists at the U.S. Army Research Laboratory. To achieve this goal, predictive capabilities that use Navier-Stokes computational techniques have been developed and applied to an extensive number of projectile configurations. A summary of code validation efforts and applications for both spin-stabilized and fin-stabilized projectile configurations are described. Significant progress in the predictive capability for projectile aerodynamics has been achieved through the availability of substantial supercomputer resources and modern computational techniques. Current and future research areas of interest are described and provide an indication of computer resources and code enhancements needed to continue the progress in projectile computational aerodynamics. 44 refs.

Method and apparatus for determining the general direction of the origin of a projectile

Abstract: Methods and apparatus are provided for determining the general direction of the origin of a projectile. At least one sensor, having at least three spaced-apart transducers, each being capable of encountering a blast wave generated at an origin of and by a propellant for the projectile, is provided for generating a signal responsive thereto. From the signals, a time relation is measured between at least three transducers when the blast wave serially encounters each of the three transducers. From the time relations, at least one unit sighting vector from at least one sensor to the origin of the blast wave is determined so that the unit sighting vector points in the general direction of the origin of the projectile.

An optimal design of capacitor-driven coilgun

Abstract: The paper presents an analysis and optimal design of a capacitor-driven inductive coilgun. An equivalent circuit is used for a launch simulation of the coilgun. The circuit equations are solved together with the equation of motion of the projectile by using the Runge-Kutta method. The numerical results are compared with the experimental values to verify the usefulness of the developed simulation program. It is shown that the numerical and the experimental results are in a good agreement. In the design of the system optimization is achieved by employing the genetic algorithm. The resultant specifications of the coilgun optimally designed by the proposed algorithm are tested by experiment. Finally the obtained results are compared with those designed by approximate equations and by linear search methods as well. It is found that the proposed algorithm gives a better result in the energy efficiency of the system, namely it enables one to obtain a higher muzzle velocity of the projectile with the same amount of energy. >

Muzzle-loaded expanding projectile for firearms, kits for manually producing expanding projectile for muzzle-loaded firearms and methods for manually producing expanding muzzle-loaded projectiles

Abstract: A system modified so that an axial ram rod, centering jag and configuring die can be used to simultaneously tamp or size a projectile while forming the projectile into a hollow-nose type which mushrooms when configuring a spherical or double-ogival projectile into the mushrooming-type; and a kit comprising a case and sealing lid enabling a user in the field to optionally select a centering jag conforming to the caliber of the weapon being loaded, and for optionally forming a hollow-nose projectile with a "punch" characteristic in accordance with the nature of the target.

Method and apparatus for sensing speed and position of projectile striking a target

Abstract: A method and apparatus is disclosed for sensing the position and speed (force) of a projectile striking a target of arbitrary size and shape. The strike produces an acoustic shock wave which travels outward from the point of impact, striking several acoustic sensors at the periphery of the target. The resulting sensor's electrical waveforms are then analyzed to determine the position (from waveform timing) and speed (from waveform amplitude) of the projectile strike,

RAM accelerator system and device

Abstract: A method for accelerating projectiles comprises introducing the projectile into an accelerator barrel, feeding a combustible gas mixture into said barrel and igniting said mixture to accelerate the projectile, and is characterized in that a fluid is stored in the projectile and is ejected therefrom into the space between the projectile and the barrel. Suitable accelerator systems are disclosed.

Hook and loop fastened projectile and target device

Abstract: A projectile and target device includes a spherical projectile having a plurality of hook-threaded sheet members arcuately coated on a spherical core of the spherical projectile to fully cover the surface area of the projectile, and a target having a loop-threaded fabric sheet secured to a supporting screen, whereby upon throwing of the spherical projectile to the target, the projectile will be attached on the target by fastening the hook-threaded sheet members on the spherical projectile with the loop-threaded fabric sheet of the target, without loosening or releasing of the hook-threaded sheet members from the spherical projectile.

Computation of the Roll Moment for a Projectile with Wrap-Around Fins

Abstract: Flowfield solutions of a projectile with wrap-around fins have been computed for velocities ranging from Mach 1.3 to Mach 3.0. The flowfield solutions were computed with a time-marching, three-dimensional, zonal, full Navier-Stokes code. The roll moment coefficient was computed from the flowfield solutions and compared to the roll moment coefficient obtained experimentally for a similar wrap-around fin projectile. The roll moment coefficient computations show favorable agreement with experimental measurements in predicting changes of the roll moment coefficient magnitude and sign as a function of the flight Mach number. This demonstrates computational fluid dynamics' capability as a promising method for reliably predicting the roll moment coefficient of projectiles with wrap-around fins.

Three-dimensional flow calculations for a projectile with standard and dome bases

Abstract: Test firings of the 155-mm XM825 artillery projectile have shown that its flight performance was affected by configurational changes to the base cavity. This was an unexpected result, and a clear understanding of why these changes affected the flight behavior did not exist. A computational study has been made for the two different base-cavity configurations which were flight tested. Flowfield computations have been performed at 0.8

Charge-pickup by heavy relativistic nuclei.

Abstract: In the interactions of relativistic heavy projectile nuclei with target nuclei there is a measurable probability for the projectile nuclei to pick up a charge during the interaction. We report here new measurements, made in a wide range of targets, of the cross sections for charge-pickup of gold nuclei with energies of 10.6 GeV/nucleon, and of silver and krypton nuclei with energies between 1.4 and 0.5 GeV/nucleon. The excitation functions of these cross sections are discussed using all the measurements available to us and indicate that there are significant decreases in the cross sections as the energies increase. A weak target dependence is seen. Previously these cross sections have been reported to have a strong, approximately quadratic, dependence on the projectile mass. This conclusion has to be modified in the light of these new measurements. Instead, we suggest that the cross sections show a strong exponential dependence on either the fractional neutron excesses or, equivalently, on the neutron to nucleon ratios of the projectile nuclei.

Toy projectile launching devices

Abstract: Projectile launching toys include a surface (13, 17, 17') suitably configured to support and guide a projectile (20, 20'), a lever (30, 30') pivotally mounted so as to traverse a portion of the surface in the direction the projectile is being guided, a manual actuator (40) coupled to the lever to manually move the lever from an initial position to a second pivoted position to launch the projectile, and a return member (60) coupled with the lever to automatically return the lever to its original position after being manually moved and released.

Wall for protection against shaped charges and kinetic-energy projectiles

Abstract: In the case of a protective wall for protection against shaped charges and kinetic-energy projectiles, a large number of intermediate walls are provided, which extend approximately parallel in the firing direction. The intermediate spaces between the intermediate walls are filled with a liquid or with a brittle solid material whose shock wave impedance is different from that of the intermediate walls. The distance between the intermediate walls is in this case designed such that a hole channel, which is produced by the shaped charge or by the kinetic-energy projectile, in the liquid or in the solid material is at least partially closed again by means of the shock wave, which is reflected on the intermediate walls, of the liquid or the solid material, before the shaped-charge jet or the kinetic-energy projectile emerges from the intermediate space having the hole channel. A shaped-charge jet is in this way disturbed at specific points, the individual jet parts being partially deflected from the axial direction, or completely destroyed.

Penetration force measurement of thin plates by laser Doppler anemometry

Abstract: An experimental method is developed by applying laser-Doppler anemometry (LDA) to measure the velocity history of a projectile impact on a target. The force history was obtained by assuming the projectile to be rigid and by differentiating a polynomial which best fitted the obtained velocity data. This method was then applied to the impact of a hemispherically tipped striker on 1-mm thick aluminum plates. The initial velocity of the projectile ranged from several m/s to 93.5 m/s. When these velocities were low enough not to produce cracks on the plate, double-force peaks were observed in each test, and the value corresponding to the higher peak was proportional to the initial velocity of the projectile. Further, this peak force occurred when the projectile just started to rebound, and spring-back behavior of the plate always occurred. Once the cracks on the target started to form, the peak impact force dropped, and the double-peak phenomenon disappeared. It was also found that the peak force was at approximately the same level for impact speeds above the ballistic limit of the plate. On the other hand, a power law was found to perfectly fit the relationship between the absorbed kinetic energy and the initial velocity of the projectile when it was lower than the ballistic limit.

Charge exchange and electron emission in slow collisions of highly charged ions with C60

Abstract: We simulated the population dynamics of target and projectile levels during the interaction of slow, highly charged ions and C60. Our investigation is based on a semiclassical over-barrier description of long-range charge exchange and a spherical model for the C60 cluster. It includes the transient formation of hollow atoms and relaxation of the projectile due to Auger cascades. As a first application, we consider slow Ar8+ projectiles and give estimates for the occupation changes of all coupled target and projectile levels, charge-state evolutions and energy-resolved spectra of emitted Auger electrons. Our results are in satisfactory agreement with recent experimental data.

Hand launchable hydrodynamic recreational device

Abstract: A recreational device in the form of an elongate projectile is described. The projectile has a body including a nose region, a mid-region and a tail region. Preferably, the projectile is provided with a fillable cavity for adjusting its buoyancy. The body has a size, mass, length-to-diameter ratio, specific gravity and contour that facilitate its stable distant travel through a liquid medium such as water. Importantly, the projectile has a specific gravity of between 0.95 and 1.05, which renders it neutrally buoyant in most fresh water bodies. In a preferred embodiment of the invention, the recreational device for stabilization purposes against undesirable yaw, pitch and roll has arcuately spaced, radially extending fins in a tail region of the body. When launched by hand underwater, the device maintains an imparted trajectory and slips cleanly through the water over a great distance.

Passive infrared bullet detection and tracking

Abstract: An apparatus and method for passively detecting a projectile such as, for example, a bullet using a passive infrared detector. A passive infrared detector is focused onto a region in which a projectile is expected to be located. Successive images of infrared radiation in the region are recorded. Background infrared radiation present in the region is suppressed such that second successive images of infrared radiation generated by the projectile as the projectile passes through the region are produced. A projectile path calculator determines the path and other aspects of the projectile by using the second successive images of infrared radiation generated by the projectile. The present invention, in certain embodiments, also determines the origin of the path of the projectile and takes a photograph of the area surrounding the origin and/or fires at least one projectile at the area surrounding the origin of the path of the projectile.

Size and excitation energy distributions of projectile spectators in multifragmentation data.

Abstract: The size and energy distributions of spectators in ALADIN fragmentation experiments with gold projectiles are inferred from experimental data. For the most violent collisions of Au on Cu, the mean projectile spectator has the size of an iron nucleus, with an excitation energy of about 23 MeV/nucleon. We claim that a correct interpretation of these data should take into account the large range covered by the extracted distributions, which are in good agreement with the prediction of the Boltzmann-Uheling-Uhlenbeck calculations and with those of a new diabatic abrasion model.