ionocraft

An ionocraft or ion-propelled aircraft, commonly known as a lifter or hexalifter, is an electrohydrodynamic (EHD) 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 so-called "electrogravitics" proponents, especially on the Internet, where it is commonly referred to as a lifter.

The term "lifter" is an accurate description because it is not an anti-gravity device, but produces lift in the same sense as a rocket from the reaction force from driving the ionized air downward. Much like a rocket or a jet engine, the force that an ionocraft generates is oriented consistently along its own axis, regardless of the surrounding gravitational field. Claims of the device working in a vacuum also have been disproved.

Ionocraft 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.