The Biefeld–Brown effect is an effect that was discovered by Paul Alfred Biefeld (CH) and Thomas Townsend Brown (USA). The effect is more widely referred to as electrohydrodynamics (EHD) or sometimes electro-fluid-dynamics, a counterpart to the well-known magneto-hydrodynamics. Extensive research was performed during the 1950s and 1960's on the use of this electric propulsion effect during the publicized era of the United States gravity control propulsion research (1955 - 1974). During 1964, Major Alexander Procofieff de Seversky had in fact published much of his related work in U.S. Patent 3,130,945 , and with the aim to forestall any possible misunderstanding about these devices, had termed these flying machines as ionocrafts. In the following years, many promising concepts had to be abandoned due to technological limitations and were forgotten. The effect has only recently become of interest again and such flying devices are now known as EHD thrusters. Simple single-stage versions lifted by this effect are sometimes also called lifters.

An ionocraft or ion-propelled aircraft, commonly known as a lifter, is an electrohydrodynamic device (utilizing an electrical phenomenon known as the Biefeld–Brown effect) to produce thrust in the air, without requiring any combustion or moving parts. The term "Ionocraft" dates back to the 1960s, an era in which EHD experiments were at their peak. In its basic form, it simply consists of two parallel conductive electrodes, one in the form of a fine wire and another which may be formed of either a wire grid, tubes or foil skirts with a smooth round surface. When such an arrangement is powered up by high voltage in the range of a few kilovolts, it produces thrust. The ionocraft forms part of the EHD thruster family, but is a special case in which the ionisation and accelerating stages are combined into a single stage.

The device is a popular science fair project for students. It is also popular among anti-gravity or electrogravitics proponents, especially on the Internet, where it is commonly referred to as a lifter. This term is somewhat of a misnomer, since it implies the force can act only against gravity, which is clearly not the case; the magnitude of thrust is totally independent from the mass of the device and its direction is always in the direction of its own axis. Claims of the device working in a vacuum have also been disproven. Due to its popularity, the lifter was featured and vacuum tested in the Discovery Channel science program MythBusters, episode 68. The effect was determined to be thrust rather than anti-gravity.

Ionocrafts require many safety precautions due to the high voltage required for their operation, and also the risk of premature death from heart or lung disease due to the inhalation of their ionised air product, ozone. A large subculture has grown up around this simple EHD thrusting device and its physics are now known to a much better extent.

EHD thruster stands for electrohydrodynamic thruster. This is the general and most appropriate term used for high voltage devices that propel air or other fluids, to achieve relative motion between the propulsion device and the propelled fluid. EHD thrusters, unlike the related ion thruster family, do not need to carry their own supply of propellant gas, although they still need to carry their own electrical power source or generator. Also, unlike related propulsion devices, they need a fluid for their operation and cannot operate in space or vacuum.

An EHD thruster is a propulsion device based on ionic fluid propulsion, that works without moving parts, using only electrical energy. The principle of ionic (air) propulsion with corona-generated charged particles has been known since the earliest days of the discovery of electricity, with references dating back to year 1709 in a book titled Physico-Mechanical Experiments on Various Subjects by Francis Hauksbee. The first publicly demonstrated tethered model was developed by Major De Seversky in the form of an Ionocraft, a single stage EHD thruster, in which the thruster lifts itself by propelling air downwards (see Newton's Third Law of Motion). De Seversky contributed much to its basic physics and its construction variations during the year 1960 and has in fact patented his device U.S. Patent 3,130,945 , April 28, 1964). Only electric fields are used in this propulsion method. The basic components of an EHD thruster are two: an ioniser and an ion accelerator. Ionocrafts form part of this category, but their energy conversion efficiency is severely limited to less than 1% by the fact that the ioniser and accelerating mechanisms are not independent. Unlike the ionocraft, within an EHD thruster, the air gap in its second stage is not restricted or related to the Corona discharge voltage of its ionising stage. Also, EHD thrusters are not restricted to air as their main propulsion fluid, and work perfectly in other fluids, such as oil.

For More Information: Ionocraft Lifters: K-12 Experiments & Background Information

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