Showing papers on "Projectile published in 1985"

Performance loss due to wall ablation in plasma armature railguns

Abstract: on results that illustrate the importance of wall ablation. Section 111 develops a simple model of a plasma armature incorporating wall ablation. The model is applied first to the analysis of a constant current railgun to show how ablation affects railgun behavior and then to the experimental data of Section 11. Section IV develops an extension to the simple ablation model that includes viscous drag on the arc plasma. Again comparisons with the data of Section I1 support the inclusion of viscous drag as an important process in railguns. Finally, in Section V the future of plasma armature railguns is examined with particular emphasis on scaling to large devices and techniques to eliminate Parametric measurements have been performed on a plasma armature railgun at Las Alamos. The railgun is extensively instrumented for studies of the projectile motion and its interaction with the plasma armature. The most important parameter, driving current, was varied from 100 kA to 400 kA. Additional parameters investigated include current waveform, injection velocity, injection gas, wall insulation material, and initial pressure. For all combinations of parameters investigated, the measured performance was substantially below theoretical or control the ablation process. predictions. A strong correlation was found between performance loss and abnormal plasma armature features such as multiple arc formation, or separation of the armature from the projectile. In extreme cases, the plasma armature was observed to come to rest inside the railgun. A plasma armature model has been developed which successfully accounts for the measured performance loss and for many of the abnormal plasma armature features. By incorporating the ablation of wall material into the armature plasma thismodel predictstwo parasitic forces that dominate the motion of the armature at high velocity. One force is the inertial drag term mav. The other is frictional drag between the hot, turbulent plasma and the walls, which increases as m,v2. Simple scaling relations, which incorporate the plasma I. Experimental Apparatus The experimental results reported below were obtained with the HYVAX Phase I (HYVAX-I) railgun. The HYVAX railgun is a high performance modular device designed for distributed operation. It has a design length of 13 m and a theoretical velocity capability of 25 km/s at a design current of 500 kA. HYVAX-I consists of two 1.22 m long barrel modules and three 0.30 m long current connection modules from the H W A X device. The modules are assembled as a single stage railgun with an effective lenmh of2.5 m. A cross section ofthe barrel is shown ~ armature model, rho; that velocities >IO km/s wil l he ex. tremely dificult to achieve with plasma armature railguns unless the effects ofablation are eliminated or carefull, controlled.

The new isotopes258105,257105,254Lr and253Lr

Abstract: Evaporation residues from the heavy-ion fusion reaction50Ti on209Bi were investigated. They were separated from the projectile beam by the velocity filter SHIP and identified after implantation into an array of position-sensitive surface-barrier detectors by analyzing theirα-decay chains. Spontaneous fission was also observed.

Cartridge for frangible projectile

Abstract: A cartridge with a frangible projectile, usable in an automatic or semi-automatic fire-arm, for instance a pistol, wherein the propellant gases are initially expanded to recoil the breech block and then further expanded to propel the frangible projectile without breaking the same until impact.

Projectile, for example for hunting purposes, and process for its manufacture

Abstract: A projectile suitable for example for hunting purposes, with a body tapering toward its forward end, comprising in the area of its tapered forward end a plurality of weakened locations in the form of cuts and/or notches extending at an angle obliquely to its longitudinal axis. The cuts or notches offer resistance to the rotation of the projectile in flight, so that the rotation of the projectile will be braked in flight, and projectile will drop rapidly after passing through the range of the target desired. Upon impact on a target, however, the rotation of the projectile, reduced while in flight, is appreciably enhanced and a cleaner entry and passage of the projectile is attained.

Energy requirements for the penetration of heads of domestic stock and the development of a multiple projectile.

Abstract: The forces and kinetic energy required to penetrate the isolated heads of calves, adult beef cattle, sheep and red deer with a metal probe the same diameter as the bore of an experimental pistol were determined. Approximately 16 and 127 Joules were required to penetrate the heads of adult sheep and cattle, respectively. Using these data a 10 g projectile, consisting of 49 lead pellets and a lead disc in a polyethylene sleeve, was constructed. This projectile, when fired by a charge sufficient to produce a muzzle velocity of 165 m/second, had sufficient kinetic energy to penetrate the heads and brains of cattle, sheep, horses and deer. The projectile was fired from a new design of humane killer with a spring loaded barrel and fitted with a silencer. After penetration of the frontal bones the projectile fragmented and the kinetic energy of its individual particles were insufficient for them to penetrate the opposite side of the head of any of the animals, including one-week-old calves. Fragmentation also caused more brain damage and inhibition of spinal reflexes than a solid free bullet or captive bolt. It is suggested that the use of such a projectile for the emergency slaughter of animals is less hazardous than a solid free bullet and is easier to use and more effective than either a solid free bullet or captive bolt. The projectile was not suitable for killing adult pigs because of problems associated with the frontal sinus.

Low velocity expanding projectile

Abstract: A projectile for a centerfire cartridge that achieves maximum energy transfer with limited target penetration when fired from snub-nosed pistols. A hollow point lead bullet is provided with an aluminum jacket of sufficient hardness to avoid fouling the pistol barrel and which allows the cartridge containing the projectile to feed reliably in auto-loading pistols and yet does not restrict normal expansion of the bullet upon impact with the target. The jacket extends into the nose recess of the bullet and covers the peripheral portion of the bullet base, whereby the jacket is securely fastened to the bullet and separation subsequent to impact is prevented. The jacket is uniformly notched at the nosetip annulus to weaken the aluminum jacket and promote upset at surprisingly low impact velocities. A method of fabricating the projectile is also disclosed in which a cup-shaped aluminum jacket is partially filled with a lead core and simultaneously the cup base is notched before being formed into a hollow point bullet nose configuration. The notches can thus be uniformly controlled in contrast to slitting or cutting before or after forming in which the sharpness and force applied to the cutting knife governs the size of the slit or cut in a hard to control fashion.

Device for producing a decoy cloud, in particular an infrared decoy cloud

Abstract: Device for producing a series of consecutive decoy clouds, in particular infrared decoy clouds which move progressively away from the actual target, in which several projectiles (A, B, C, D, E, F, G) are arranged within a thin walled discharge tube (1), each projectile is practically of identical construction and has a separate ignition disintegrator unit (10) for disintegrating it and for igniting and scattering the combustible charge (18) to form a decoy cloud, a separate ejection chamber (27) provided with a propellant charge cartridge (28) is provided on each projectile, each propellant charge cartridge (28) can be ignited via a separate electrically actuated ignition lead (5) by means of a command controlled ignition distributor unit (69) and each projectile has a separate percussion fuse (47) for the ignition disintegrator unit (10) which can be actuated by releasing its safety device (360 mechanically, its safety device (36) only being released after ignition of the propellant charge cartridge (28) with opening of the ejection chamber (27) and after the projectile has left the discharge tube (1) and due to the acceleration of the projectile.

Cross sections for the production of highly charged argon and xenon recoil ions in collisions with high-velocity uranium projectiles

Abstract: Cross sections for the production of recoil ions were measured for collisions of highly charged Un+ (n approximately=65-75) projectile ions with argon and xenon as a function of the projectile velocity (3.6-15.5 MeV u-1) and the final charge states of both collision partners. A recoil-ion-projectile-ion coincidence technique made it possible to distinguish between pure ionisation of the target and ionisation of the target plus capture of one or more electrons into bound state of the projectile (CI). It was found that hydrogen-like and bare argon ions are most efficiently produced at the highest velocity investigated by pure ionisation with cross sections that exceed 10-18 cm2. Highly charged xenon ions, however, are also most effectively created at the highest velocity but via the CI reaction channel.

Electromagnetic projectile launching system

Abstract: An electromagnetic projectile launcher has a barrel (10) formed with parallel firing rails (13, 14) and separate supply conductors (18, 19) which are connected to the firing rails to supply firing current to one and receive the firing current from the other. The supply conductors (18, 19) are formed about the bore (11) of the barrel as sectors of a cylinder and are coaxial with one another such that current in adjacent portions of the two supply conductors flow in opposite directions. Very little time varying magnetic field is produced within the bore of the barrel (11) or outside of the supply conductors (18, 19) as a result of firing currents flowing in the supply conductors and in the firing rails. The magnetic field which accelerates a projectile through the bore is provided from a persistent magnet (26), which may be superconducting, formed about the bore in a dipole configuration to provide a constant magnetic field substantially transverse to the path of the projectile through the barrel.

Method and apparatus for estimating trajectory

Abstract: A method and apparatus for estimating the trajectory of a projectile using two interferometric radar antennas each producing a group of interferometric antenna lobes forming intersecting solid angles, and being directed at an elevation angle so that the projectile passes through each interferometric antenna lobe. Each radar antenna transmits a different frequency of pulsed RF power and receives pulsed RF signals reflected from the projectile whenever the projectile passes through the antenna lobes of the radar antennas. Based on the received signals of respective radar antennas, the range and time information for the projectile passing through the antenna lobes of the respective radar antennas can be obtained. From this range and time information, the three-dimensional coordinates, speed and acceleration at the points in the antenna lobes through which the projectile passes can be obtained. From the 3-dimensional coordinates and the speed and acceleration of the projectile, the trajectory of the projectile can be estimated.

Computations of projectile Magnus effect at transonic velocities

Abstract: : The Magnus effect has long been the nemesis of shell designers. Although very small in magnitude, on the order of 1/10th the normal force, this spin-induced side moment has a significant destabilizing effect on projectiles. A combined computational and experimental research program has been ongoing at BRL in recent years to develop a predictive capability for the Magnus effect in particular and for projectile aerodynamics in general. This effort has been very successful in the supersonic regime. The research to be reported in this paper is an extension of this effort into the transonic regime. Utilizing the time marching, thin-layer Navier-Stokes computational technique developed at NASA ames Research Center, solutions have been obtained for a spinning, 6-caliber long, ogive-cylinder-boattail shape at Mach = 0.91 and angle of attack = 2degrees. The computed results predict the correct development of the Magnus force along the body, and comparisons between the computation and experiment are very favorable. Details of the flow field solution such as turbulent boundary- layer velocity profiles and surface pressure distributions are presented. The components which contribute to the Magnus effect are determined and presented as a function of axial position. A complete set of aerodynamic coefficients have been determined from the flow field solutions. Those to be presented here and compared with experimental data include the normal force and Magnus force coefficients. The computations for this research effort were obtained both on a CDC 7600 computer and Cray 1S. (etc.)

Throw and catch game

Abstract: The invention is a throw and catch game in which the projectile is covered with a Velcro™ material and the receivers for catching the projectile are placed on the elbows or knees of a person so that the projectile will stick to the receivers when they are in contact.

Total K-shell Coulomb ionization cross sections at very-low projectile energies

Abstract: The first-order semiclassical approximation method with hyperbolic projectile trajectories, velocity symmetrization, relativistic electronic wavefunctions and target recoil amplitudes is used for systematic studies of K-shell Coulomb ionization. The first-order description is modified by the use of a binding correction. In the low projectile velocity region studied the theoretical cross sections are largely consistent with weighted averaged measurements. Two sets of empirical reference cross sections are considered, the first being found to contain an additional superfluous target dependence, the second improved set showing considerably increased agreement with the present SCA results. The inadequacy of the ECPSSR model for the very low projectile energy region is demonstrated. The implications for the construction of model independent empirical scaled cross sections are discussed.

Unusual Behavior of Projectile Fragments from the Interaction of Copper with Relativistic Ar Ions

Abstract: Projectile fragments formed in the interaction of 0.9A-GeV and 1.8A-GeV /sup 40/Ar ions with a Cu disk interact with a second Cu disk and the relative yields of products in the two disks are measured by radioactivation techniques as a function of the distance between them. The data at 1.8A-GeV demand either (1) decay in flight (t/sub 1/2/roughly-equal10/sup -10/ s) of some projectile fragments having large cross sections or (2) production of secondaries with unexpectedly large transverse momenta.

Armor piercing small caliber projectile

Abstract: A small caliber armor-piercing bullet is described in which a case hardened steel nosed lead projectile is utilized to help reduce projectile fragmentation at impact.

Projectile having extendable wings

Abstract: A projectile possessing extendable wings or fins which are adapted to be pivoted radially outwardly of the projectile. The wing or fin includes a flexible covering and a tensioning device; for example, a strut arrangement, and with the wing or fin being displaceable from a retracted position prior to launch of the projectile to an outwardly extended position in which the applicable covering portion is tensioned by the tensioning device so as to thereby provide a stable, predetermined aerodynamically defined wing or fin configuration.

Parameter Analysis of a Single Stage Induction Mass Driver

Abstract: : The electromechanical behavior of a Single Stage Induction Mass Driver (SSIMD) has been modeled and analyzed with the aid of a computer. The analysis focused on the effects of circuit parameters on projectile velocity and system efficiency. A description of the model along with general rules for the design of efficient SSMID systems are presented.

Shape of the electron capture to the continuum cusps for H, H2, and He targets in the velocity range 6.3-18.0 a.u.

Abstract: A general purpose projectile-frame expansion fitting method is used to characterize the shape of the electron capture to the continuum (ECC) cusp for bare carbon, oxygen, neon, and argon projectiles, incident on atomic and molecular hydrogen, and helium targets, over the velocity range 6--18 a.u. The method used to fit the ECC cusp shape allows the direct comparison of spectra taken under differing instrumental conditions in an apparatus-independent manner. The results reveal a substantial similarity in the ECC cusp shape for a wide variety of projectile Z, projectile velocity, and target combinations which has not yet been explained by current theories which predict the shape of the ECC cusp.

Shaped charge projectile system

Abstract: A subcaliber projectile (22) which is launched from a full bore projectile (20) having a shaped charge warhead (28) prior to impact with the target. The subcaliber projectile is tethered to the full bore projectile by means of a fine electrical cable (24) of fixed length which serves as the communication link between the two projectiles with the length of the cable determining the fuzing standoff distance. The ballistic coefficient of the subcaliber projectile (22) is made such that the subcaliber projectile (22) always flies ahead of the full bore projectile (20).

Variable timing and power storage arrangements

Abstract: A variable timing power storage arrangement for pre-setting a time interval between launch of a projectile and the initiation of a particular function or functions of said projectile and for storing power required inter alia for the initiation of said function or functions at the expiration of said interval, the arrangement comprising inductive coupling means for establishing before launch of the projectile an electrical coupling path between the projectile and control means associated with projectile launching means, signal generating means associated with the control means for generating a train of tone-burst modulated pulses for transmission over said inductive coupling means to the projectile, rectifying means in said projectile for rectifying the pulses of said train the first of which is utilized for charging up power storage capacitor means in the projectile to provide a d.c. power supply which serves inter alia for subsequently initiating a function or functions of the projectile and the subsequent pulses of said train being utilized for the setting of counter means in the projectile in accordance with the requisite duration of the time interval between launch of the projectile and initiation of the aforesaid particular function or functions and means in the projectile responsive to the firing or launch of said projectile to cause the counter means to commence a counting-out operation at a predetermined rate at the termination of which the power storage capacitor means is discharged for the initiation of said function or functions of the projectile.

Projectile and impactor designs for plate-impact experiments

Abstract: The use of plate-impact techniques for producing a variety of loading histories in plane wave experiments is discussed. Specific techniques concern direct shock compression, shock compression followed by unloading, shock compression followed by further loading, shock compression followed by unloading and then reloading (cyclic loading), shockless compression (quasi-isentropic loading), and pressure-shear loading. Emphasis is placed on the considerations of projectile and impactor design and the constraints of structural loading during projectile acceleration, which are associated with these loading conditions.

Electromagnetic launcher with a passive inductive loop for rail energy retention or dissipation

Abstract: An electromagnetic projectile launching system is provided with a passive, conductive loop for energy retention, dissipation or recovery. In a parallel rail launcher, this passive loop is inductively coupled to substantially link magnetic flux produced within the launcher by current flowing in a pair of parallel projectile launching rails. During projectile acceleration, parasitic current flow in the passive inductive loop turn or turns is prevented by a rectifier array. When the projectile exits, post-firing rail inductive energy is inductively and rapidly transferred to the passive inductive loop and is either dissipated there or may be beneficially employed to help accelerate a successive projectile.

Armored-piercing projectile (penetrator)

Abstract: An improved armor-piercing penetrator projectile includes a core made of a material having a high tungsten content which is in metallic form. The front portion of the core is in the shape of a hemisphere and includes a nose point in the form of a ballistic hood. The core extends or occupies the entire cross-section of the projectile and has a high length/diameter-relationship. The hemispherical front portion of the core is adapted to directly contact a target upon impact of the projectile.