초록 ▼

Electromagnetic propulsion device as a gun or reversible electric motor having a barrel with a cavity extending its length, an armature in said cavity with a permanent magnetic or energized propulsion bus coil, a plurality of wall conductors orthogonal and circumscribing the cavity distributed betwe

Electromagnetic propulsion device as a gun or reversible electric motor having a barrel with a cavity extending its length, an armature in said cavity with a permanent magnetic or energized propulsion bus coil, a plurality of wall conductors orthogonal and circumscribing the cavity distributed between the cavity ends with contact means at the cavity on one end and a bus common with all wall conductors on the other and wherein the magnetic fields of the barrel wall conductor coils immediately before and after the magnetic field source in an armature interacts therewith effecting armature motion. Forward and aft armature current shunts direct current from barrel rails to and from the armature coil with associated propulsion bus-aft shunt circuit means, when extant, and to and from said armature propelling wall conductors via said contacts.

대표청구항 ▼

The invention claimed is: 1. Electromagnetic propulsion devices comprising: a barrel; a cavity therein which extends the length of said barrel and having: a breech end opening at one end and a muzzle end opening at the other barrel end and a central axis which extends from said breech end opening t

The invention claimed is: 1. Electromagnetic propulsion devices comprising: a barrel; a cavity therein which extends the length of said barrel and having: a breech end opening at one end and a muzzle end opening at the other barrel end and a central axis which extends from said breech end opening to said muzzle end opening, and a uniform right section profile to said central axis throughout said cavity; and a first barrel rail and a second barrel rail and said barrel rails are: power rails, and parallel to one another, and located in said barrel cavity's wall, and electrically insulated from direct electrical continuity with each other, and each said barrel power rail has: continuous barrel cavity surface along its length, and connection means to outside said barrel for attachment to a power source; and a wall conductor assembly comprised of: a barrel bus that is: located outside said barrel cavity, and electrically insulated from direct electrical continuity with said barrel power rails, and located along the same length of the barrel as said barrel power rails; and a plurality of wall conductors that are: located outside said barrel cavity, and parallel to one another, and oriented orthogonal said barrel cavity axis, and separated from one another, and distributed along the length of said barrel bus, and each said wall conductor of said plurality of wall conductors: is a continuous insulated conductor between its ends, and has electrical continuity at one end with said barrel bus, and includes between its ends a coil that: circumscribes the barrel cavity one or more times, and circumscribes the barrel cavity in the same direction from said barrel bus as all other wall conductor coils of said plurality of wall conductors; and contact means for each wall conductor of said plurality of wail conductors that: is located proximal the end of said wall conductor that is distal said wall conductor's end with said barrel bus continuity, and has electrical continuity with said wall conductor's barrel bus distal end, and extends through a mating opening in the barrel cavity wall and has surface in the barrel cavity; and armatures for propulsion through said barrel cavity and each said armature has: a central axis that is, with said armature in said barrel cavity, coincident the central axis of said cavity or close and parallel said axis, and a muzzle end that is, with said armature in said barrel cavity, the armature's end closest to said cavity's muzzle end, and a breech end that is, with said armature in said barrel cavity, the armature's end closest to said cavity's breech end, and all right section profiles to said central axis smaller than said barrel cavity's right section profile, and a permanent magnet that is: polarized in the direction of said armature axis, and located midway between said armature's muzzle and breech ends, and a forward current shunt that: is located in the surface of said armature and near the muzzle end of said armature, and has surface that, with said armature in said barrel cavity, is at and has continuous electrical continuity the cavity surface of said first barrel power rail, and said continuity is sliding electrical continuity with armature movement in the barrel cavity, and has surface that, with said armature in said barrel cavity, is at and has continuous electrical continuity with said contact means of said wall conductor assembly at the instant barrel cavity location of said shunt surface and said continuity is sliding electrical continuity with armature movement in the barrel cavity, and said forward current shunt of an armature in the barrel cavity is electrically insulated from direct electrical continuity with said second barrel power rail, and said wall conductor assembly has additionally, with an armature in said barrel cavity, forward wall conductors comprised of: the group of one or more consecutive wall conductors of said wall conductor assembly whose contact means at any instant have said electrical continuity with said forward current shunt surface at said contact means; and said forward current shunt of an armature in said barrel cavity, via said shunt's continuous electrical continuity with said first power rail and said shunt's continuous electrical continuity with said forward wall conductors of said wall conductor assembly, maintains continuous electrical continuity between said first barrel power rail and said forward wall conductors, and, with power supplied by an outside power supply to said power rails via said connection means of said rails, maintains a current path between said first power rail, and said forward wall conductors; and an aft current shunt that: is located in the surface of said armature and near the breech end of said armature, and with said armature in said barrel cavity, has surface with continuous electrical continuity with the cavity surface of said second barrel power rail and has surface at and with continuous electrical continuity with said contact means of said wall conductor assembly at the instant barrel cavity location of said shunt surface and said continuity is sliding continuity with armature movement in the barrel cavity, and said aft current shunt is electrically insulated from direct electrical continuity with said first barrel power rail; and said wall conductor assembly has additionally, with said armature in said barrel cavity, aft wall conductors comprised of: the group of one or more consecutive wall conductors of said wall conductor assembly whose contact means at any instant have said electrical continuity with said aft current shunt surface at said contact means; and said aft current shunt of an armature in said barrel cavity, via said continuous electrical continuity with said second power rail and said continuous electrical continuity with said aft wail conductors of said wall conductor assembly, maintains continuous electrical continuity between said second power rail and said aft wall conductors, and with power supplied by an outside power supply to said power rails via said connection means of said rails, maintains a current path between said power rail and said aft wall conductors; and said barrel bus of said wall conductor assembly, with an armature in said barrel cavity, provides continuous electrical continuity between said forward wall conductors and said aft wall conductors of said wall conductor assembly and with power supplied by an outside power supply to said power rails, provides a current path between said forward wall conductors and said aft wall conductors; and wherein, with: an armature in the barrel cavity and power supplied to said power rail's connection means by an outside source, and the polarity of said barrel power rails with reference to each other so that: the magnetic fields of the current in said forward wall conductors interact with the armature's magnet creating forces of attraction on said magnet, and the magnetic fields of the current in said aft wall conductors interact with the armature's magnet creating forces of repulsion on said magnet, and said forces of attraction and repulsion on the armature's magnet have cavity axis parallel, muzzle directed components which propel the armature through the barrel cavity from breech to muzzle. 2. Electromagnetic propulsion devices as claimed in claim 1 used as a reversible electric motors wherein: one of said armatures is retained in the barrel cavity for bidirectional movement therein; and said armature has additionally power take-off means; and the direction of said armature's barrel cavity traverse is reversed by reversing the polarities of said barrel power rails with reference to each other so that: the magnetic fields of the current in said forward wall conductors interact with the armature's magnet creating forces of repulsion on said magnet, and the magnetic fields of the current in said aft wall conductors interact with the armature's magnet creating forces of attraction on said magnet, and said forces of attraction and repulsion on the armature's magnet have cavity axis parallel, breech directed components which propel the armature through the barrel cavity in the muzzle to breech direction. 3. Electromagnetic propulsion devices comprising: a barrel; and a cavity therein which extends the length of said barrel and having: a breech end opening at one end and a muzzle end opening at the other barrel end and a central axis which extends from said breech end opening to said muzzle end opening and a uniform right section profile to said central axis throughout said cavity; and two pairs of barrel rails not both the same and said barrel rails are: power rails, and parallel to one another, and located in said barrel cavity's wall, and located along the same length of the barrels and electrically insulated from direct electrical continuity with each other, and each said barrel power rail has: continuous barrel cavity surface along its length and power connection means to outside said barrel for attachment to an outside power source; and a wall conductor assembly comprised of: a barrel bus that is: located outside said barrel cavity, and electrically insulated from direct electrical continuity with said barrel power rails, and located along the same length of the barrel as said power rails; and a plurality of wall conductors that are: located outside said barrel cavity, and parallel to one another, and oriented orthogonal said barrel cavity axis, and separated from one another, and distributed along the length of said barrel bus, and each wall conductor of said plurality of wall conductors: is a continuous insulated conductor between its ends, and has electrical continuity at one end with said barrel bus, and includes between its ends a coil that: circumscribes the barrel cavity one or more times, and circumscribes the barrel cavity in the same direction from said barrel bus as all other wall conductor coils of said plurality of wall conductors; and contact means for each wall conductor of said plurality of wall conductors that: is located proximal the end of said wall conductor that is distal said wall conductor's end with said barrel bus continuity, and has electrical continuity with said wall conductor's barrel bus distal end, and extends through a mating opening in the barrel cavity wall and has surface in the barrel cavity; and armatures for propulsion through said barrel cavity and each said armature has: a central axis that is, with said armature in said barrel cavity, coincident the central axis of said cavity or very close and parallel said axis, and a muzzle end that is, with said armature in said barrel cavity, the armature's end closest said cavity's muzzle end, and a breech end that is, with said armature in said barrel cavity, the armature's end closest said cavity's breech end, and all right section profiles to said axis smaller than said barrel cavity's right section profile, and a portion of said profiles like said barrel cavity's right section profile but slightly undersized thereof; and a propulsion bus that includes between its ends a coil which circumscribes the armature axis one or more times, and, that is: a continuous insulated conductor between its ends, and located midway between the armature's muzzle and breech ends, and oriented orthogonal said armature's central axis, and located in said armature where said cavity's right section profile and said armature's right section profiles are similar, and located within said armature, in, at or proximal said armature's surface, that in said barrel cavity, is proximal said cavity's surface, and said propulsion bus, with said armature in said barrel cavity, has: at one end, surface with continuous electrical continuity with the cavity surface of one of said barrel power rails that is proximal said propulsion bus end and said electrical continuity is continuous sliding electrical continuity with movement of said armature in the barrel cavity, and at its other end, surface with continuous electrical continuity with the cavity surface of a second of said barrel power rails that is proximal said other end and said electrical continuity is continuous sliding electrical continuity with movement of said armature in said barrel cavity; and a forward current shunt that: is located in said armature's surface between said propulsion bus and said armature's muzzle end and, has surface that, with said armature in said barrel cavity, is at and has continuous electrical continuity with the cavity surface of one of said barrel power rails, and said continuity is sliding electrical continuity with armature movement in the barrel cavity, and has surface that, with said armature in said barrel cavity, is at and has continuous electrical continuity with said contact means of said wall conductor assembly at the instant barrel cavity location of said shunt surface and said continuity is sliding electrical continuity with armature movement in the barrel cavity, and said forward current shunt of an armature in the barrel cavity is electrically insulated from direct electrical continuity with the remaining barrel power rails; and said wall conductor assembly has additionally, with an armature in said barrel cavity, forward wail conductors comprised of: the group of one or more consecutive wall conductors of said wall conductor assembly whose contact means at any instant have said electrical continuity with said forward current shunt surface at said contact means; and said forward current shunt of an armature in said barrel cavity, via said shunt's continuous electrical continuity with said power rail and said shunt's continuous electrical continuity with said forward wall conductors of said wall conductor assembly, maintains continuous electrical continuity between said barrel power rail and said forward wall conductors, and, with power supplied by an outside power supply to said power rails, maintains a current path between said barrel power rail, and said forward wall conductors; each said armatures also has an aft current shunt that: is located in the armature's surface between the propulsion bus and the breech end of said armature, and with said armature in said barrel cavity, has surface that is at and has continuous electrical continuity with the cavity surface of a barrel power rail that: does not have direct electrical continuity with said forward current shunt, and does not have direct electrical continuity with the propulsion bus when said propulsion bus and said forward current shunt have direct electrical continuity with the cavity surface of the same barrel power rail, and has surface that is at and has continuous electrical continuity with said contact means of said wall conductor assembly at the instant barrel cavity location of said shunt surface and said continuity is sliding electrical continuity with armature movement in the barrel cavity, and said aft current shunt of an armature in the barrel cavity is electrically insulated from direct electrical continuity with the other said barrel power rails; and said wall conductor assembly has additionally, with an armature in said barrel cavity, aft wall conductors comprised of: the group of one or more consecutive wall conductors of said wall conductor assembly whose contact means at any instant have said electrical continuity with said aft current shunt surface at said contact means; and said aft current shunt of an armature in the barrel cavity, via said shunt's continuous electrical continuity with said barrel power rail and said shunt's continuous electrical continuity with said aft wall conductors of said wall conductor assembly, maintains continuous electrical continuity between said barrel power rail and said aft wall conductors, and, with power supplied by an outside power supply to said power rails, maintains a current path between said barrel power rail, and said aft wall conductors; and said barrel bus of said wall conductor assembly, with an armature in said barrel cavity, provides continuous electrical continuity between said forward wall conductors and said aft wall conductors of said wall conductor assembly and with power supplied by an outside power supply to said power rails, provides a current path between said forward wall conductors and said aft wall conductors; and wherein, with an armature in said barrel cavity, and with power supplied by an outside power source to: said connection means of the power rail with said electrical continuity with said forward current shunt, and said connection means of the power rail with said electrical continuity with said aft current shunt, and with power supplied by an outside power source to: said connection means of the power rail with said electrical continuity with one end of said propulsion bus, and said connection means of the power rail with continuous electrical continuity with the other end of said propulsion bus, and the polarity of said connections arranged so that: the magnetic fields of current in said forward walls conductors interact with the current in said propulsion bus creating forces in said propulsion bus with cavity axis parallel, muzzle directed components, and the magnetic fields of current in said aft wall conductors interact with the current in said propulsion bus creating forces in said propulsion bus with cavity axis parallel, muzzle directed components, and said cavity axis parallel, muzzle directed force components, propel the armature through the barrel cavity from breech to muzzle. 4. Electromagnetic propulsion devices as claimed in claim 3 wherein said barrel cavity has a twist so that: consecutive right sections at constant axial increments through said barrel cavity have a constant rate of angular rotation about said cavity's axis; and armatures for use in said barrel cavity have a twist so that: consecutive right sections at constant axial increments through each said armature has the same constant rate of angular rotation about said armatures s axis as said cavity's and said twist imparts rotation to said armatures during their barrel cavity traverse. 5. Electromagnetic propulsion devices as claimed in claim 3 used as a reversible electric motors wherein: one of said armatures is retained for reversible movement in said barrel cavity, and said armature has additionally a power take-off means, and wherein the direction of said armature's barrel cavity traverse is reversed by reversing the polarities with respect to each other of: said power rail with continuous electrical continuity with said forward current shunt and said power rail with continuous electrical continuity with said aft current shunt, or of said power rail with continuous electrical continuity with one end of said propulsion bus and said power rail with continuous electrical continuity with the other end of said propulsion bus, so that: the magnetic fields of current in said forward wail conductors interact with said armature's propulsion bus current creating forces in said propulsion bus with cavity axis parallel, breech directed components, and the magnetic fields of current in said aft wall conductors interact with said armature's propulsion bus current creating forces in said propulsion bus with cavity axis parallel, breech directed components, and said cavity axis parallel, breech directed force components propel the armature through the barrel cavity in a muzzle to breech direction. 6. Electromagnetic propulsion devices as claimed in claim 5 wherein each said barrel cavity has a twist so that: consecutive right sections at constant axial increments through said barrel have a constant rate of angular rotation about said cavity's axis; and said armatures for use in said barrel cavity have a twist so that: consecutive right sections at constant axial increments through said armatures have the same constant rate of angular rotation about said armature's axis and said twist imparts rotation to said armatures during their barrel cavity traverse. 7. Electromagnetic propulsion devices as claimed in claim 3 wherein said two pairs of barrel power rails not both the same, is comprised of four separate barrel power rails and one power rail of the first pair of power rails has continuous electrical continuity with said forward current shunt of an armature in said barrel cavity and the second power rail of the first pair of power rails has continuous electrical continuity with said aft current shunt of an armature in said barrel cavity, and one power rail of the second pair of power rails has continuous electrical continuity with one end of said propulsion bus of an armature in said barrel cavity, and the second power rail of the second pair of power rails has continuous electrical continuity with the other end of said propulsion bus of an armature in said barrel cavity. 8. Electromagnetic propulsion devices as claimed in claim 7 wherein said barrel cavity has a twist so that: consecutive right sections taken at constant axial increments through the barrel have a constant rate of angular rotation about the cavity axis; and armatures for use in said barrel cavity have a twist so that: consecutive right sections taken at constant axial increments through said armatures have the same constant rate of angular rotation about the armature axis as said barrel and said twist imparts rotation to said armatures during their barrel cavity traverse. 9. Electromagnetic propulsion devices as claimed in claim 7, used as a reversible electric motor wherein: one of said armatures is retained for reversible movement in said barrel cavity, and said armature has additionally power take-off means, and wherein the direction of the armature's barrel cavity traverse is reversed by reversing the power rail polarities with reference to each other in one of said two pairs of power rails so that: the magnetic fields of current in said forward wall conductors interact with the armatures s propulsion bus current creating forces in the propulsion bus with cavity axis parallel, breech directed components, and the magnetic fields of current in said aft wall conductors interact with the armature's propulsion bus current creating forces in the propulsion bus with cavity axis parallel, breech directed components, and said cavity axis parallel, breech directed force components propel said armature in said barrel cavity in the muzzle towards breech direction. 10. Electromagnetic propulsion devices as claimed in claim 9 wherein the barrel cavity has a twist so that: consecutive right sections through the barrel have a constant rate of angular rotation about the cavity axis per unit axis distance; and armatures for use in said barrel cavity have a twist so that: consecutive right sections through said armatures have the same constant rate of angular rotation about the armature axis per unit axis distance; and said twist imparts rotation to said armature during their barrel cavity traverse. 11. Electromagnetic propulsion devices comprising: a barrel; a cavity therein which extends the length of said barrel and having: a breech end opening at one end and a muzzle end opening at the other barrel end and a central axis which extends from said breech end opening to said muzzle end opening and a uniform right section profile to said central axis throughout said cavity; and two barrel rails which are: power rails, and parallel to, to one another and located in said barrel cavity's wall, and electrically insulated from direct electrical continuity with each other, and each said power rail has: continuous barrel cavity surface along its length and connection means to outside said barrel for attachment to a power source; and a wail conductor assembly comprised of: a barrel bus that is: located outside of said barrel cavity, and electrically insulated from direct electrical continuity with said barrel power rails, and located along the same length of the barrel as said power rails; and a plurality of wall conductors that are: located outside of said barrel cavity, and oriented orthogonal said barrel cavity axis, and parallel to one another, and separated from one another, and distributed along the length of said barrel bus, and each wall conductor of said wall conductor plurality: is a continuous insulated conductor between its ends, and has electrical continuity at one end with said barrel bus, and includes between its ends a coil that: circumscribes the barrel cavity one or more times and circumscribes the barrel cavity in the same direction from said continuity with said barrel bus as all other wall conductor coils of said plurality of wall conductors; and contact means for each wall conductor of said plurality of wall conductor that: is located proximal the end of said wall conductor that is distal said wall conductor's end with said barrel bus continuity, and has continuous electrical continuity with said wall conductor's barrel bus distal end, and extends through a mating opening in the barrel cavity wall and has surface in the barrel cavity; and armatures for propulsion through said barrel cavity and each said armature has: a central axis that is, with said armature in said barrel cavity, coincident the central axis of said cavity or very close and parallel the cavity central axis, and a muzzle end that is, with said armature in said barrel cavity, the armature's end closest the cavity's muzzle end, and a breech end that is, with said armature in said barrel cavity, the armature's end closest the cavity's breech end, and all right section profiles to said axis smaller than said barrel cavity's right section profile, and a portion of said profiles like said barrel cavity's right section profile but slightly undersized thereof; and a propulsion bus that is: a continuous insulated conductor between its ends, and located midway between said armature's muzzle and breech ends, and oriented orthogonal said armature's central axis, and located in said armature where said cavity's right section profile and said armature's right section profiles are similar, and located within said armature, in, at or proximal said armature's surface that in said barrel cavity is proximal said cavity's surface, and that includes between its ends a coil which circumscribes said armature axis one or more times, and that has, with said armature in said barrel cavity, surface at one end with continuous electrical continuity with said cavity surface of one of said power rails and with armature movement in said barrel cavity said electrical continuity is continuous sliding electrical continuity and continuous electrical continuity at its other end with propulsion bus-aft shunt circuit means; and a forward current shunt that: is located in said armature's surface between said propulsion bus and said armature's muzzle end, and, with said armature in said barrel cavity, is proximal the second of said barrel power rails and has surface with continuous electrical continuity with the cavity surface of said power rail and with armature movement in said barrel cavity said electrical continuity is continuous sliding electrical continuity and is insulated from direct electrical continuity with the first said power rail, and has surface at and with continuous electrical continuity with said contact means of said wall conductor assembly at the instant barrel cavity location of said shunt surface and said continuity is sliding electrical continuity with armature movement in the barrel cavity; and said wall conductor assembly has additionally, with an armature in said barrel cavity, forward wall conductors comprised of: the group of one or more consecutive wall conductors of said wall conductor assembly whose contact means at any instant have said electrical continuity with said forward current shunt surface at said contact means; and said forward current shunt of an armature in said barrel cavity, via said shunt's continuous electrical continuity with said power rail and said shunt's continuous electrical continuity with said forward wall conductors of said wall conductor assembly, maintains continuous electrical continuity between said barrel power rail and said forward wall conductors, and, with power supplied by an outside power supply to said power rails, maintains a current path between said barrel power rail, and said forward wall conductors; and each said armature also has an aft current shunt that: is located in the armature's surface between said propulsion bus and said armature's breech end, and, with said armature in said barrel cavity, has continuous electrical continuity with propulsion bus-aft shunt circuit means, and has surface at and with continuous electrical continuity with said contact means of said wall conductor assembly at the instant barrel cavity location of said shunt surface and said continuity is sliding electrical continuity with armature movement in the barrel cavity, and said aft current shunt of an armature in the barrel cavity is electrically insulated from direct electrical continuity with said barrel power rails; and said wall conductor assembly has additionally, with an armature in said barrel cavity, aft wall conductors comprised of: the group of one or more consecutive wall conductors of said wail conductor assembly whose contact means at any instant have said electrical continuity with said aft current shunt surface at said contact means; and said aft current shunt of an armature in said barrel cavity, via said shunt's continuous electrical continuity with said propulsion bus-aft shunt circuit means and said shunt's continuous electrical continuity with said aft wall conductors of said wall conductor assembly, maintains continuous electrical continuity between said propulsion bus-aft shunt circuit means and said aft wall conductors, and, with power supplied by an outside power supply to said power rails, maintains a current path between said propulsion bus-aft shunt circuit means, and said aft wall conductors; and said barrel bus of said wall conductor assembly, with an armature in said barrel cavity, provides continuous electrical continuity between said forward wall conductors and said aft wall conductors of said wall conductor assembly and with power supplied by an outside power supply to said power rails, provides a current path between said forward wall conductors and said aft wall conductors; and said propulsion bus-aft shunt circuit means is comprised: an electric current bus in said armature that is located: proximal said current shunts therein, and between and connecting the end of said propulsion bus distal said propulsion bus's end with said power rail continuity and said aft current shunt; and wherein with power supplied to the power rails by an outside power supply so that: the magnetic fields of current in said forward wall conductors interact with the current in said propulsion bus creating forces in said propulsion bus with cavity axis parallel, muzzle directed components, and the magnetic fields current in said aft wall conductors interact with the current in said propulsion bus creating forces in said propulsion bus with cavity axis parallel, muzzle directed components, and said cavity axis parallel, muzzle directed force components, propel the armature through the barrel cavity from breech to muzzle. 12. Electromagnetic propulsion devices as claimed in claim 11 wherein said barrel cavity has a twist so that consecutive right sections through the barrel have a constant rate of angular rotation per unit cavity axis distance about said cavity axis; and said armatures for use in said barrel cavity have a twist so that consecutive right sections through said armatures have the same constant rate of angular rotation per unit axis distance about the armature axis; and said twist imparts rotation to said armatures during their traverse from said barrel cavity's breech to muzzle. 13. Electromagnetic propulsion devices as claimed in claim 11 but wherein said propulsion bus-aft shunt circuit means is comprised: a third barrel rail that: is located in said barrel wall, and has continuous barrel cavity surface along its length, and is electrically isolated from said barrel power rails, is parallel said barrel power rails, and is located along the same barrel cavity length as said power rails; and additional surface on said propulsion bus that is: proximal said bus's end that is distal said bus's end with power rail continuity, and that, with said armature in said barrel cavity, is at and has continuous electrical continuity with the barrel cavity surface of said third rail and said continuity is sliding electrical continuity with armature movement in the barrel cavity; and additional surface on said aft current shunt that, with said armature in said barrel cavity, is at and has continuous electrical continuity with the barrel cavity surface of said third barrel rail and said continuity is sliding electrical continuity with armature movement in the barrel cavity; and said propulsion bus-aft shunt circuit means, with said armature in said barrel cavity, maintains continuous electrical continuity between said propulsion bus and said aft current shunt and maintains a current path between said propulsion bus and said aft current shunt, with power supplied by an outside power supply to said power rails. 14. An electromagnetic propulsion device as claimed in claim 13 wherein the barrel cavity has a twist so that consecutive right sections through the barrel have a constant rate of angular rotation about the cavity axis per unit cavity distance; and armatures for use in said barrel cavity have a twist so that consecutive right sections through said armatures have the same constant angular rate rotation about the armature axis per unit axis distance, and said twist imparts rotation to said armature during their barrel cavity traverse.