Abstract: An integrated switch-preaccelerator system for use in an electromagnetic launcher includes a pair of spaced generally parallel preaccelerator rails, a pair of spaced first and second conductive switch terminal elements disposed adjacent upstream ends of the rails, and three coaxially arranged conductive tubular members enclosing and extending axially along the rails, one of which being movable relative to the others between conducting and non-conducting positions.

Abstract: A high pressure plasma initially formed from a fluidizable substance in a confined region of a passage behind a projectile in the passage initially accelerates the projectile toward an open end of the passage. The plasma is intially derived by supplying a discharge current to an electrode in the substance. The plasma in the confined region is ohmically heated by an azimuthal current generated in the plasma by an AC magnetic field that is coaxial with the passage or by a discharge current flowing longitudinally through the passage and projectile. A cartridge includes the projectile and a wall of the passage that is evaporated after the projectile has been fired so the evaporant flows out of the passage after the projectile.

Abstract: An electromagnetic gun comprises a barrel for containing and directing an electrically conductive projectile and a plurality of inductors which are arranged in series relationship along the barrel so as to create magnetic fields which accelerate the projectile along the barrel. Each inductor is associated with a pair of rail electrodes within the barrel bore which, when bridged by the projectile, short circuit their associated inductor to provide additional acceleration of the projectile.

Abstract: A high pressure plasma initially formed from a fluidizable substance in a confined region of a passage behind a projectile in the passage initially accelerates the projectile toward an open end of the passage. The plasma in the confined region is ohmically heated to a higher pressure by a discharge current flowing longitudinally through the passage and the projectile.

Abstract: A rail gun projectile includes superconducting material. Current from a DC power supply flows between the rails through the superconducting material with a component at right angles to the elongated direction of the rails. The superconducting material is of a type that the current flowing through it produces a force for driving the projectile longitudinally along the rails. Metal abutting against the superconducting material shunts current from the power supply around a portion of the superconducting material having a tendency to go normal to the remainder of the superconducting material in the superconducting state.

Abstract: An electromagnetic launcher system for small diameter high velocity penetrator projectiles and larger diameter, slower projectiles is provided with a single high current pulse power supply. At least two bores of substantially different cross section are connected to the power supply. Augmentation conductors are utilized adjacent the larger diameter bore to achieve the desired acceleration of the large diameter projectile with a smaller root mean square current than used for the acceleration of the small diameter projectile to a desired high velocity.

Abstract: Apparatus for providing a controlled increase in muzzle velocity of a projectile while reducing peak value of gas pressure inside a gun barrel. A cartridge includes an elongated body having a central bore divided into three chambers, with a fuel chamber separated from an oxidizer chamber and an elongated capillary chamber by a plurality of membranes. A fuse wire and a power supply vaporize a plasma base in the capillary chamber and provide a controlled jet to provide combustion between a second fuel in the fuel chamber and an oxidizer material in the oxidizer chamber. The power supply controls the fuel-oxidizer combustion rate to obtain a relatively steady pressure of long duration against the projectile which results in high projectile velocity with relatively low peak values of pressure in the gun barrel.

Abstract: In an electromagnetic launcher such as a railgun for propelling a projectile at high velocity, an overpulse energy recovery circuit is employed to transfer stored inductive energy from a source inductor to the railgun inductance to propel the projectile down the railgun. Switching circuitry and an energy transfer capacitor are used to switch the energy back to the source inductor in readiness for a repetitive projectile propelling cycle.

Abstract: A railgun operates at high pressure (up to 350 MPa) without structural damage and is readily disassembled for inspection, maintenance and component testing. A rail assembly is pressed into a hoop-wound epoxy fiberglass containment tube and clamped within a steel compression frame. The geometry of the rail assembly permits rail movement without insulator intrusion and achieves bore sealing during rail movement at maximum pressure. The rail assembly also has replaceable insulator inserts which are isolated from rail re-bound shock. Fused quartz insulator inserts provide the best results. A flash tube is provided at the gun muzzle to suppress precursor discharge and commutate precursor current back to the armature. To realize increased velocity without sacrificing in-bore projectile stability, a cut-corner projectile is used having a L/D ratio as small as 0.65 which reduces the mass by about 11%.

Abstract: The direct projection of a space vehicle, herein termed a "Space Train.TM.", into space without combustile fuel is described. A mathematical physics analysis derives critical ranges of parameters, which inlcude a vehicle having a mass of about 3,000,000 Kg., a length of about 180 m and 5 m dia.; an acceleration of about 8 g's during its travel within 1000 km of a vacuum tube parallel to Earth's surface to a velocity of about 12 km/sec., the vehicle exiting from the tube into the atmosphere at an angle of about 3.degree. and an elevation of about 3 km at a maximum deceleration of about 8 g's. An acceleration or deceleration of 8 g's is tolerable to humans in the special chair described herein. The energy imparted to this mass is provided by a conventional electric power source stored as electric energy in superconducting storage inductor rings. The electric energy is discharged to coils around the vacuum tube just in advance of the center of the moving vehicle.

Abstract: Hypervelocity magnetic induction accelerators are disclosed which create a traveling magnetic wave behind a projectile without the use of sliding contacts or multiple triggered switches. Inductive and resistive parameters are established as a function of position along a stator coil to obtain the magnetic wave in response to the pulsed DC power source. The ratio of the resistance to the inductance is a decreasing function of position from the breech to the muzzle. In a preferred embodiment the stator coil has a multiplicity of stages, and the DC pulse is delayed by inductances to progressively excite the stages, and the current from the pulse is fed through resistances to provide voltages for diverting the current to the next stages. In an alternative embodiment the magnectic field from the stator coil progressively diffuses through a tapered conductive or ferromagnetic sleeve disposed in the stator coil.

Abstract: An electromagnetic gun assembly includes a gun barrel, a projectile structure disposed within the gun barrel, and a plurality of bore rider members disposed between the projectile structure and the gun barrel. The bore rider members are dimensioned and arranged to maintain the projectile structure spaced-apart from the gun barrel, restrict lateral movement of the projectile structure relative to the gun barrel, accommodate ablative mass loss, and accommodate static and dynamic gun barrel expansion. Each bore rider member has a tapered shape that includes converging first and second surfaces, the first surface facing the gun barrel, the second surface facing the projectile structure, and the first and second surfaces converging in a direction opposite to a direction of acceleration in which the projectile structure is to be accelerated along the gun barrel.

Abstract: A muzzle switch connected to the rails of an electromagnetic launcher to divert post-launch rail current into a dump resistor or other load and to prevent arcing at the muzzle. The switch includes shorting members electrically connected to the launcher rails together with a flexible washer-like ring which surrounds the rails and is in close proximity to the shorting members. Part of the rail current is diverted through the ring and when a current carrying armature which propels a payload along the rails passes the switch the interaction of the magnetic field produced by the rail current and current in the ring forces the ring against the shorting members, thus closing the switch as the armature leaves the rails.

Abstract: An electromagnetic railgun launcher and armature. The armature is made from superconducting material and is levitated between the rails of the launcher by the Meissner effect. The Meissner effect is created by cooling the armature and subjecting it to a magnetic field. The armature configuration has a closed loop topology and defines two planes - one plane coincides with the plane of the rails; the other plane is oblique to the first. The armature configuration, when placed between the rails receives an unbalanced Lorentz force which accelerates the armature.

Abstract: A railgun with superconducting rails. The device features rails made from ceramic materials capable of becoming superconducting at relatively high temperatures. Some embodiments utilize rails made entirely from superconducting ceramics while other embodiments utilize rails with metallic cores covered by layers of superconducting ceramics. Cooling of the superconducting ceramic to a temperature below its critical temperature is accomplished by liquid nitrogen cryorefrigerator or a compressed gas cryorefrigerator.

Abstract: An electromagnetic projectile launcher is provided with muzzle circuitry which increases the rate of dissipation of inductively stored rail energy following the launch of a projectile and can be used to recover a portion of that stored energy for use in successive launches. The muzzle circuitry includes a pair of conductors which lie adjacent to the projectile launching rails and conduct current in a direction which is opposite to the current flow in the projectile rails. These conductors may be connected to a pulse transformer to increase the post-launch current of an inductive energy storage device. In an alternative embodiment, a capacitive muzzle circuit is used to store the inductive rail energy and inject current into the projectile launching rails during the launch of a successive projectile.

Abstract: An electromagnetic railgun. The device features two electrically connected arallel rails. One end of each rail may be connected to a D.C. voltage source. At least one of the rails has a hole for closely receiving a metallic projectile. When the projectile is within the hole and the voltage is applied, currents flow through the two rails. Interaction of the currents with the self generated magnetic field causes a repulsive force between the two rails and launches the projectile outward from the rails.

Abstract: A composite electromagnetic barrel is preloaded to minimize rail separation by jacking the rails radially outwardly away from each other and wedging a pair of insulating members between the rails to retain the preload. The jacking force is then released.

Abstract: A very low inductance, very low resistance, command operated repetitive high current opening switch is described which uses a Lorentz force to move a conductive liquid between a conducting region and an insulated region between two electrodes. In a specific embodiment, a cylindrical outer electrode coaxially surrounds in a spaced relationship a generally cylindrical inner electrode. The annular space between the inner and outer electrodes is divided into first and second sections along the length of the electrodes. Intermeshing continuous spiral fins are defined on the facing surfaces of the inner and outer electrodes along the first section of the length of the opening switch. Insulation covers the surfaces of the inner and outer electrodes surrounding the second section.

Abstract: An electromagnetic projectile launcher is provided with a firing switch which alternately opens and closes to repeatedly commutate current from a high current supply to a pair of projectile launching rails. A rotor having a transverse conducting element is rotated within and moved axially along a cylindrical stator. Brush members which have widths which decrease in an axial direction along the stator are shorted by the conducting element between shots for varying lengths of time as the rotor travels axially along the stator.

Abstract: An electromagnetic railgun. The device features two electrically connected parallel rails. One end of each rail may be connected to a D.C. voltage source. At least one of the rails has a hole for closely receiving a metallic projectile. When the projectile is within the hole and the voltage is applied, currents flow through the two rails. Interaction of the currents with the self generated magnetic field causes a repulsive force between the two rails and launches the projectile outward from the rails.

Abstract: A power supply generating a reaction torque generally simultaneously with its power output is utilized to supply power to fire the railgun. The power supply and the railgun are cooperatively mounted together such that the reaction torque of the power supply upon discharge counteracts the recoil force of the railgun, thereby transferring lateral forces through the compulsator to a position in the power supply which is removed from the position of the coupling between the railgun and the power supply.

Abstract: An alternator for repetitive pulsing of an electromagnetic projectile launcher is provided with a stator structure having at least one pair of single layer concentric coil portions which are electrically connected in parallel. A rotating magnetic field induces a voltage in these coil portions without producing circulating currents. The alternator is connected through a switch to a pair of genrally parallel conductive projectile launching rails and a sliding conductive armature between the rails. By causing the switch to conduct at a predetermined phase angle, the voltage across the launching rails can be reduced to zero as the projectile leaves the rails. Where a succession of projectiles is to be fired, the phase angle at which the switch begins to conduct is controlled in order to achieve a substantially constant muzzle velocity for each projectile while minimizing the rail voltage as each projectile exits the rails.

Abstract: An electromagnetic railgun. The device features two electrically connected parallel rails. One end of each rail may be connected to a D.C. voltage source. At least one of the rails has a hole for closely receiving a metallic projectile. When the projectile is within the hole and the voltage is applied, currents flow through the two rails. Interaction of the currents with the self generated magnetic field causes a repulsive force between the two rails and launches the projectile outward from the rails.

Abstract: A projectile suitable for use with an electromagnetic launcher or railgun. he projectile has a detachable conductive header portion which mates closely with and is restrained by one of the rails of a railgun. The header eliminates arcing and rail damage. The remainder of the projectile is ejected through a hole in the header toward a target.

Abstract: An electromagnetic launcher includes a plurality of electrical stages which are energized sequentially in synchrony with the passage of a projectile. Each stage of the launcher includes two or more coils which are arranged coaxially on either closed-loop or straight lines to form gaps between their ends. The projectile has an electrically conductive gap-portion that passes through all the gaps of all the stages in a direction transverse to the axes of the coils. The coils receive an electric current, store magnetic energy, and convert a significant portion of the stored magnetic energy into kinetic energy of the projectile by magnetic reconnection as the gap portion of the projectile moves through the gap. The magnetic polarity of the opposing coils is in the same direction, e.g. N-S-N-S.

Abstract: A railgun with superconducting rails. The device features rails made from ceramic materials capable of becoming superconducting at relatively high temperatures. Some embodiments utilize rails made entirely from superconducting ceramics while other embodiments utilize rails with metallic cores covered by layers of superconducting ceramics. Cooling of the superconducting ceramic to a temperature below its critical temperature is accomplished by liquid nitrogen cryorefrigerator or a compressed gas cryorefrigerator.

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.

Abstract: An Earth-based, rapid-fire, electromagnetic accelerator system is provided for launching multiple hypervelocity nuclear or non-nuclear independently targetable warheads on ballistic trajectories to targets located anywhere on or above the Earth's surface. The warheads are mounted inside a reinforced launching sabot containing a plurality of coaxial superconducting dipole magnets. The sabot is magnetically accelerated to hypervelocities inside a large-bore vacuum tube by sequentially exciting a series of driving coils mounted coaxially along the tube. The sabots are injected into the tube from pre-evacuated storage canisters thereby eliminating the need for an air-lock. Terminal guidance systems allow the warheads to be fired over intercontinental distances to hit small, preselected targets with nearly perfect accuracy. The launch velocities are sufficiently high to enable warheads to also intercept and destroy orbiting satellites moving in space high above the Earth's surface.

Abstract: A joint is provided for joining together two sections of a tube wherein the sections are prestressed by a surrounding pressure medium to press the sections together and to resist forces tending to separate the sections and the bursting pressure inside the tube. The pressure medium can be a resin which can be pressurized and subsequently cured or a fluid. The outside diameter of each section, at and near the end to be joined, is enlarged. A coupling means encircles the enlarged portions and couples the two sections together. One or more expandable pressure cavities located within said coupling means and/or within the enlarged portions have the general shape of a flared annuli. The pressure medium fills and expands the pressure cavities and, when pressurized, exerts stresses compressing both sections together at the joint and also applies relatively uniform radial stress in the vicinity of the end of each section.

Abstract: An electromagnetic parallel rail launcher with an augmentation winding for post-firing inductive energy recovery. A power supply includes a storage inductor which, in conjunction with the inductance of the augmenting winding, provides the inductive energy storage prior to firing. As the launcher projectile exits, the storage inductor is substantially decoupled from the rail and augmenting winding inductance, so that a high efficiency inductive energy transfer may be accomplished between the rails and augmenting winding.

Abstract: An electrostatic kinetic energy weapon for firing projectiles at speeds up to and in excess of 100 kilometers per second. The weapon having a projectile launcher for launching projectiles using interactive forces acting between charged elements.

Abstract: A rapid-fire electromagnetic projectile launcher. The invention features parallel disks with gaps in their peripheries. A voltage source is applied to the disks to cause current to flow in opposite directions through the disks, generating a strong repulsive force which is utilized to eject a projectile. A rotator is positioned concentric with the disks to control timing of the repulsive action and facilitate projectile reloading.

Abstract: An electromagnetic launcher having spaced-apart rails for launching a projectile includes a plurality of stages connected to the rails for supplying makeup current during a projectile launch. Each stage includes an inductive power supply and an electrically conducting loop physically adjacent the rails for a predetermined length and including a conducting switch, such as a controlled rectifier array. As a projectile launching armature enters the loop area, a countercurrent is built up in the loop and at current zero the switch reverts to a non-conducting condition, thereby causing injection of the inductive current into the rails.

Abstract: A lightweight, portable, electromagnetic railgun. The invention features a conventional railgun coupled to a magnetic flux compression generator (MFCG) section and an injector section. The conventional railgun has two parallel metallic rails (13,15) with a bullet (25) slidably positioned between them. The bullet is rapidly projected between the rails toward a chosen target when a current flows between the rails (and through the bullet). The MFCG section provides a source of high current to the rails. The MFCG section has a piston (73) which moves between two energized bars (51,53). A magnetic field is created by current flowing in a circuit through the piston, (73) the bars (51,53) and the bullet (25). The associated magnetic flux is rapidly compressed as the piston moves between the bars. Compression of the magnetic flux produces a large current pulse which is coupled to the rails (13,15) to propel the bullet (25).

Abstract: This invention provides a liquid propellant gun embodying a first species of this invention wherein the inner differential area piston is controlled by a variable damping mechanism, and both pistons have respective cross-sectional areas coupled to the pumping chamber.

Abstract: A projectile for use in an electromagnetic projectile launcher is provided with a conductive open loop which is mechanically attached to the body of the projectile. Means are provided for electrically connecting the open loop between a pair of generally parallel projectile launching rails when the open loop is in a predetermined angular orientation with respect to the rails. Current flowing in the loop then interacts with magnetic flux produced by current flowing within the rails to place a torque on the loop which can be used to spin-stabilize the projectile or to prevent rotation of the projectile depending upon the particular application.

Abstract: A very low inductance, high current, repetitive opening switch for railguns. A specific embodiment has a circular rotor positioned behind the rails with its rotational axis coaxial with the railgun projectile path defined by the rails. The face of the rotor facing the rails has at least one conducting and at least one insulating region, each symmetric about a diameter of the rotor. A pair of current collectors, or brushes, are positioned against the rotor face so that the rotor, when rotating, will alternately conduct and insulate current between the current collectors as conducting or insulating rotor regions sweep past the brushes, thereby communicating current between the switch and the rails. A specific embodiment of the invention has the conducting region the shape of a diametric strip, or shorting bar, and each current collector substantially the shape of an annular segment. The current collectors are made as a plurality of conductive fingers.

Abstract: A muzzle arc suppressor allowing rapid repetitive refiring of railguns. A varistor or varistors electrically connect the muzzle ends of a railgun. Resistive inserts are placed inside the rails near the muzzle end. When the railgun projectile reaches the resistive inserts, the voltage across the varistor increases to above the varistor breakdown voltage, thereby commutating the railgun current from the projectile to the varistor, and dissipating excess magnetic energy through resistance heating of the varistor. The varistor is preferably made of zinc oxide, which is temperature invariant over a wide temperature range. The varistor may be pre-cooled to increase its energy absorbtion ability. A specific embodiment of the arc suppressor has the zinc oxide varistor conformably shaped to surround the rails. The conformably shaped varistor includes coolant passages.

Abstract: A safety switch for use in an inductively driven electromagnetic launcher system includes three tubular conductors each having a substantially cylindrical internal surface, wherein these internal surfaces have substantially the same internal diameter and are positioned at spaced locations along a common axis. A fourth tubular conductor having a cylindrical external surface with a diameter which is substantially equal to the internal diameters of the first three conductors. This fourth conductor is mounted for movement along the common axis such that its external surface is capable of making sliding electrical contact with the internal surfaces of the first three conductors. The external surface of the fourth conductors has sufficient axial length to be capable of making electrical contact with each of the internal surfaces simultaneously.

Abstract: A supersonic combustion ram cannon (1) includes a conical projectile (8) with a flat base (9) which produces a subsonic wake (12) as it flies through a barrel (2). The projectile is configured to avoid a normal shock, relying instead on supersonic compression, combustion and gas expansion. The supersonic combustion of a fuel-oxidizer mixture around the tail of the subsonic wake, pressurizes the wake and drives the projectile forward. By utilizing wake stabilized supersonic combustion, the compression and combustion pressures can be matched to the limiting barrel working pressure, thereby providing for optimum thrust and maximum projectile acceleration.

Abstract: A ram cannon (1) has an extendable barrel (2) slidably disposed over a starter cannon barrel (7). Such an extendable barrel is fully retractable during transport of the cannon and extendable at the time of firing. The barrel is also partially extendable, thereby providing a means to vary the muzzle velocity of a projectile (6) without varying the ratio of the fuel to the oxidizer in the propellant mixture. Utilizing an extendable barrel allows adapting a ram cannon to mobile artillery weapons, providing ease in transport, setup and firing, with a precise and rapid range adjustment capability.

Abstract: A repetitive resonant railgun power supply provides energy for repetitively propelling projectiles from a pair of parallel rails. The supply comprises an energy storage capacitor, a storage inductor to form a resonant circuit with the energy storage capacitor and a magnetic switch to transfer energy between the resonant circuit and the pair of parallel rails for the propelling of projectiles.

Abstract: A multiple repetitive resonant railgun power supply provides energy for repetitively propelling projectiles from a pair of parallel rails. A plurality of serially connected paired parallel rails are powered by similar power supplies. Each supply comprises an energy storage capacitor, a storage inductor to form a resonant circuit with the energy storage capacitor and a magnetic switch to transfer energy between the resonant circuit and the pair of parallel rails for the propelling of projectiles. The multiple serial operation permits relatively small energy components to deliver overall relatively large amounts of energy to the projectiles being propelled.

Abstract: A projectile is accelerated through a gun barrel bore by a cartridge containing a high temperature, high pressure plasma jet source. The cartridge has a geometry enabling it to be loaded into a breech bore of the gun. The plasma jet is supplied to the rear of the projectile and is derived by a tube having an interior wall forming a capillary passage. A discharge voltage applied between spaced regions along the capillary passage ionizes a dielectric to form a plasma. First and second ends of the passage are respectively open and blocked to enable and prevent the flow of plasma through them. The blocked end closes the breech bore.

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.

Abstract: A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

Abstract: An electromagnetic projectile launcher is provided with an insulating cartridge having an internal pressure chamber and an aperture for receiving a projectile assembly. A fuse element within the pressure chamber is electrically connected to a pair of generally parallel conductive launcher rails. Current flow through the fuse element causes it to explode and create a high pressure plasma within the pressure chamber. This high pressure plasma forces the projectile assembly to accelerate away from the cartridge and later serves as a means for conducting current between the conductive rails and for propelling the projectile assembly along the rails.

Abstract: An arrangement for propelling liquids over long distances involves enclosing liquid in a plurality of thin plastic spheres having a dimpled surface. The liquid containing spheres are propelled over substantial distances by shooting them from a pipe by means of compressed air.

Abstract: These electromagnetic guns or launchers comprise a pair of switching rails ith a slidable switching armature associated therewith for commutating a high direct current into a pair of projectile rails which are arranged in tandem with the switching rails and are electrically connected thereto. The kinetic energy of the switching armature is transferred to the projectile armature assembly so that the projectile armature assembly has an initial velocity as the current is commutated to the projectile rails. The projectile armature assembly may be mounted on and carried by the switching armature during its entire travel or the switching armature may bump the projectile armature assembly into the conductive breech region of the projectile rails at the end of its travel.