Historical research guide · 0078 · 1964
Magnetohydrodynamic propulsion apparatus
James F. King, Jr.
In one minute
James F. King, Jr. filed this in September 1964 from Winston-Salem, North Carolina — the town where Agnew Bahnson’s laboratory had been running its gravity experiments with Townsend Brown — and it was granted in 1967. King proposes a craft that carries no propellant and pushes on nothing solid. A ring of spikes at the top ionises the air as the craft meets it, wrapping the hull in a sleeve of plasma; a stack of driving rings underneath, fed with polyphase alternating current, makes a magnetic field whose strongest point sweeps repeatedly from top to bottom. That travelling field induces eddy currents in the plasma sleeve, the sleeve is driven downward, and the reaction lifts the craft — the same induction used in linear motor catapults, turned outward onto the air. King widens the rings toward the base and adds a flared skirt so the craft rights itself like a dihedral wing, and he notes the machine also works in sea water, where the medium already conducts.
Connection
This is a 1964 engineer’s answer to the same question chapters 8 and 9 ask — how a craft moves without throwing mass behind it — and his answer is the plasma sheath itself: ionise the medium, then drive it with a moving field. It is also a documented thread back to the Bahnson laboratory, and the patent settles a common confusion in its own words by separating this induction machine from Townsend Brown’s electrokinetic patents.
From the source
A travelling polyphase magnetic field induces eddy currents in a surrounding conductive medium and, by Lenz’s law, drives that medium in the direction the field travels — the working principle already in use in linear motor catapults, electric guns and electrohydraulic pumps.Description, statement of the invention
An ionizer ring at the leading end can wrap a heavier-than-air craft in an annulus of highly ionised air conductive enough to carry induced eddy currents, so the craft manufactures its own conductor out of the air it is flying through.Description, ionizer ring 21; Claim 3
Because the thrust comes from reacting against a conductive medium rather than from expelled propellant, the same craft works in air, in sea water or in any naturally conductive medium, and needs a carried ion source only where the surroundings cannot be ionised.Description, closing paragraphs
Driving rings held in a superconductive state by refrigeration carried on board give maximum field strength for minimum coil weight, with series capacitors added to cancel the inductive reactance and hold the circuit at resonance with a power factor of unity.Description, driving rings 14, 15, 16; Claim 4
Steering and attitude control come from varying the ionisation sector by sector around the ring and from the outward, downward ion flow shaped by a frusto-conical skirt, which produces a righting couple when the craft tilts, in the manner of dihedral in a winged aircraft.Description, FIGURES 4a and 4b; Claims 5, 7 and 8
King separates his machine from the electrokinetic craft of T. T. Brown — United States patents 2,949,550, 3,018,394 and 3,022,430 — which rely on generating and migrating ions between spaced electrodes at high direct-current potential rather than on induction in a moving field.Description, background
The way in
https://patents.google.com/patent/US3322374A/enHow to cite it
James F. King, Jr. (1964) Magnetohydrodynamic propulsion apparatus US3322374A