Showing papers on "Projectile published in 1968"

Ranges of projectiles in amorphous materials.

Abstract: By using an inverse power-law approximation for the interaction potential between a fast-moving projectile and the atoms of an amorphous target into which it penetrates, it is possible to calculate...

Electrically fired multiple barrel superimposed projectile weapon system

Abstract: An electrically fired multiple barrel superimposed projectile weapon system is disclosed. The system includes an array of light weight barrels with a common receiver and breech block containing piezoelectric crystals, one for each barrel providing recoil and energized charging energy source for a common battery. A removable trigger assembly contains a rechargable battery and fire rate controls. Firing control circuitry extends along the lengths of the barrels to engage firing and safety circuits associated with each round of the superimposed projectiles. Additional charging circuits for the battery are actuated by projectile travel through an air core coil, trigger release action and by an external recharger. Various forms of ammunition and firing circuitry therefore are disclosed.

Projectile with supported missiles

Abstract: A projectile is shown which has stacked bays to receive packs of flechettes. The flechettes of each pack are bound together and supported by a frangible matrix. The matrix consists of small smooth glass spheres bound together and to the flechettes by a resin. The matrix prevents the flechettes from becoming damaged during acceleration of the projectile.

Effectiveness of Meteoroid Bumpers Composed of Two Layers of Distinct Materials

Abstract: Theoretical calculations describing the response of thin plate targets to hypervelocity impact are presented. The targets are composed of two layers of distinct material, and the purpose of the studies is to determine the effect of the material discontinuity on the effectiveness of the plate in breaking up the projectile and spreading the debris in the spallation bubble as it moves downrange subsequent to penetration. The thinness of the plates and the impact velocity investigated, VQ = 1.5 cm//^sec, insure that the early stages of the process are governed by a hydrodynamic model. A particle-in-cell code (VISTA) has been used to calculate the flowfield for five impact problems affording a wide variation of those factors that might be expected to influence the effectiveness of the plate as a meteoroid shield: the shock impedance ratio (poc)i/(poc)2 across the interface in the target, the initial impact pressure produced in the projectile and target at the impact surface Sp = Si, the approximate pressure transmitted through the target to its opposite free surface £2, and the mass per unit area of the target Mt. Analysis of the results of the calculations shows that of these factors, only the mass per unit area of the target is important for the geometry and velocity investigated.

Free Surface Velocity Measurement of an Impacted Projectile by Optical Doppler Shift

Abstract: An optical technique for measuring the velocity of an accelerating, specularly reflecting surface from a position on the axis of motion has been successfully applied to a free surface velocity measurement of an impacted projectile in a pneumatic accelerator. The technique combines a laser light source, a surface tilt‐insensitive, lensless optical configuration, and a Fabry‐Perot spectrometer to obtain a velocity‐time profile of the impacted projectile. The technique involves unique features in addition to surface tilt insensitivity. These include a mode matching scheme which permits the use of high power, multilongitudinal mode lasers where formerly a single frequency laser was required. Experimental results are presented and compared with independent accelerometer measurements.

Composite preformed penetrators

Abstract: An improved armor-piercing projectile has a hard but brittle inner core metallurgically bonded to a tough but ductile outer shell which protects the core from brittle fracture on impact. The bimetallic structure of the projectile provides a higher penetration ability against ''''hard-faced'''' armor plate for a given size projectile than heretofore obtainable with homogeneous projectiles.

Penetration resistance of double sheet structures at velocities to 8.8 km/sec

Abstract: : Small pyrex glass spheres were launched into aluminum double-sheet targets at velocities to 8.8 km/sec to determine the effects of total sheet thickness and sheet spacing upon penetration resistance. The ballistic limit of double-sheet structures consisting of two equally thick aluminum sheets was found to increase with increasing total sheet thickness and sheet spacing. In addition, for a particular ratio of total sheet thickness to projectile diameter, the effectiveness of sheet spacing increases with increasing impact velocity. This effect is attributed to melting and vaporization of the projectile and front-sheet material, and it is concluded that this trend will continue as material vaporization becomes more dominant. The data of this report are used to establish the effectiveness of total sheet thickness and a lower limit for the effectiveness of sheet spacing. It was determined that the structural ballistic limit varies with the 2.5 power of the ratio of the total sheet thickness to the projectile diameter and with at least the square of the ratio of the sheet spacing to the projectile diameter. The data indicate that for impacts at a given velocity the ratio of front- sheet thickness to projectile diameter that causes maximum vaporization or fragmentation or both will result in the most efficient meteor bumper. It is concluded that the double-sheet structure most efficient in resisting penetration will use that thickness for a front sheet and the remaining available mass in the rear sheet. Measurements were also made of the front-sheet hole diameter and the front-sheet mass loss. It was determined that the front-sheet hole diameter varies with the square root of the impact velocity and the 0.45 power of the front-sheet thickness and the front-sheet mass loss varies with impact velocity and the square of the front-sheet thickness.

A Theoretical and Experimental Study of Projectile Impact on Clamped Circular Plates

Abstract: A method for the analysis of the plastic deformation of a circular plate subject to projectile impact is presented based on the assumption that the material is rigid viscoplastic, obeying a von Mises yield condition and associated flow rule. The predictions of the analysis are com­pared with the results of experiments in which projectiles of different masses are fired at various velocities at clamped plates of mild steel. The plates used in the experiments are such that substantial plastic strains can develop, while the maximum displacements are of the same order as the thickness. The analytical method presented predicts the behaviour of the plates to within the accuracy of the tests. The material constants which fit the results are in accord with those obtained from different tests.

Rocket-assisted projectile or gun-boosted rocket with supported propellant grain

Abstract: A rocket-assisted projectile having a central supporting tube surrounded by an annular propellant charge, with an annular space between the tube and propellant decreasing in width towards the rear of the projectile. The axial length of the propellant charge is less than that of the chamber containing the propellant to permit elastic deformation of the propellant in the axial direction.

Electronic ballistic computer for tank fire control system

Abstract: A computer circuit for generating signals related to the ballistics of a plurality of projectile or ammunition types, the signals including time of flight, superelevation, and ballistics drift signals. The computer includes a plurality of parallel channels, and a first adjustable operational amplifier, which operates on the range information by a selected ballistics normalizing transfer function to generate an individual normalized range signal for a selected individual one of the plurality of projectile or ammunition types, a first multiplier means for multiplying the normalized range signal received from the operational amplifier by a partial derivative of nonstandard air pressure and temperature, each parallel channel including a function generator coupled to receive and operate on the normalized range signal with a nonlinear transfer function common to the ballistics of all of the projectile types for generating an exponential function signal related to the selected projectiles, and a second adjustable operational amplifier coupled to the function generator for operating on the function signal by a selected individual unnormalizing transfer function for each projectile for generating signals related to the ballistics of the projectile, such as superelevation and time of flight on each channel and second and third multiplier means in each channel respectively coupled to multiply the superelevation signal and the time of flight signal by the partial derivative of nonstandard air temperature and air pressure conditions and by the partial derivative of nonstandard propellant grain temperature and effective full charge to correct for changes in standard conditions.

Electromagnetically energized impact forming device

Abstract: AN ELECTROMAGNETICALLY ENERGIZED IMPACT FORMING DEVICE WHEREIN A SOLID PROJECTILE IS DRIVEN AT HIGH VELOCITY AGAINST A WORKPIECE SUFFICIENT TO COLD WORK OR FORGE THE WORKPIECE INTO A PRESELECTED ON FIGURATION. THE PROJECTILE IS MOVABLE WITHIN A CONFINING BARREL OR TUBE, ONE END OF WHICH IS LOCATED AT THE STATION WHERE THE WORKPIECE IS PLACED. THE WORKPIECE MAY BE DISPOSED ON AND/OR WITHIN ANY SUITABLE WORK SURFACE SUCH AS A FORMING DIE IN SUCH POSITION TO INTERCEPT THE PROJECTILE MOVING THROUGH THE BARREL OR TUBE. A PLURALITY OF COILS SURROUND THE BARREL AND ARE ELECTICALLY ENERGIZED OR PULSED IN SUCH MANNER AS TO GENERATE MAGNETIC FIELDS LONGITUDINALLY SPACED ALONG THE LENGTH OF THE BARREL AND WHICH ARE EFFECTIVE TO PROPEL THE PROJECTILE TOWARD AND INTO ENGAGEMENT WITH THE WORKPIECE. THE COILS MAY BE REVERSIBLY ENERGIZED AT THE COMPLETION OF THE WORK STROKE OF THE PROJECTILE TO MOVE AND RETAIN THE PROJECTILE IN A RAISED POSITION TO AWAIT THE NEXT SUCCEDING CYCLE.

Switch for projectile accelerating system

Abstract: An apparatus for accelerating a projectile through the barrel of a weapon is provided by a plurality of spaced-apart stations or sections along the barrel which are responsive to the passage of the projectile and cause an electrical discharge whereby enthalpy at each station is added to the expanding gas behind the projectile resulting in an increase in the projectile velocity.

Armor piercing rocket

Abstract: An armor piercing rocket-type projectile having a drill-type penetrator embedded within the forward nose portion thereof so that upon impact the penetrator is driven forward from the projectile, into the target and displaces material as it moves therethrough.

Method and apparatus for purging liquid and liquid vapor from the inside of an elongated tube

Abstract: A SOURCE OF DRY PRESSURIZED GAS IS APPLIED ABOUT A REAR END SURFACE OF AN ELONGATED PROJECTILE IN A CONFINED SPACE TO PROPEL THE PROJECTILE INTO THE INTERIOR OF A TUBE TO BE PURGED OF LIQUID AND LIQUID VAPOR, AND THE SUPPLY OF GAS IS MAINTAINED UNDER PRESSURE ABOUT THE REAR END SURFACE OF THE PROJECTILE TO DRIVE IT TOWARD A REMOTE OPEN END OF THE TUBE.

Firing delay for point detonating fuze

Abstract: A mechanical delay for point detonating fuzes for projectiles to allow penetration into aircraft or similar light target structures before detonation of the projectile. A trans-axial inertial firing pin is mounted within the projectile so that the centrifugal force exerted thereon by the spinning projectile during light target penetration will selectively determine the firing time delay. Alternatively, instantaneous detonation is provided by a second, axial firing pin when the projectile strikes an impenetrable target or one of such hardness that would break up the projectile before the trans-axial firing pin could react to provide the normal delayed detonation.

Recoilless practice cartridge

Abstract: The recoilless practice cartridge is to be fired from the subcaliber barrel insert of a recoilless firearm and is provided with a projectile having a rearwardly opening central bore communicating with radial bores opening against an annular propellant charge surrounding a portion of the projectile. The practice cartridge case is provided with a bottom piece having one or more bores for receiving a detonator for ignition the propellant charge by passing a flame through the bores of the projectile and for thereafter conducting the propellant gas rearwardly through the cartridge case to counteract the recoil of firing the projectile from the cartridge case. Tamping means are provided for the propellant charge on the projectile and for the bottom piece bores.