The Wingless Electromagnetic Air Vehicle (WEAV) is a

heavier than air An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or by using the Lift (force), dynamic lift of an airfoil, or in ...

flight system developed at the

University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...

, funded by the

Air Force Office of Scientific Research The Air Force Research Laboratory (AFRL) is a scientific research organization operated by the United States Air Force Materiel Command dedicated to leading the discovery, development, and integration of aerospace warfighting technologies, pl ...

. The WEAV was invented in 2006 by Dr. Subrata Roy, plasma physicist, aerospace engineering professor at the

, and has been a subject of several patents.Japanese Patent no. 5,220,742 granted on March 15, 2013. The WEAV employs no moving parts, and combines the aircraft structure, propulsion, energy production and storage, and control subsystems into one integrated system.

Operating mechanism

The WEAV uses a multitude of small

electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials de ...

s covering the whole

wetted area The surface area that interacts with the working fluid or gas. In maritime industry, maritime use, the wetted area is the area of the hull (watercraft) which is immersed in water. This has a direct relationship on the overall hydrodynamic drag of ...

of the aircraft, in a multi-barrier

plasma actuator Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pl ...

(MBPA) arrangement, an enhancement over dual-electrode dielectric barrier discharge (DBD) systems using multiple layers of

dielectric material In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the mater ...

s and powered electrodes. These electrodes are very close to one another so surrounding air can be

ionized Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule ...

using RF AC

high voltage High voltage electricity refers to electrical potential large enough to cause injury or damage. In certain industries, ''high voltage'' refers to voltage above a certain threshold. Equipment and conductors that carry high voltage warrant spec ...

of a few tens of

kilovolt The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Defini ...

s even at the standard

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

of one

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

. The resultant plasma contains

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s that are accelerated by the Coulomb force using

electrohydrodynamics Electrohydrodynamics (EHD), also known as electro-fluid-dynamics (EFD) or electrokinetics, is the study of the dynamics of electrically charged fluids. It is the study of the motions of ionized particles or molecules and their interactions with ...

(EHD) at low altitude and small velocity. The surface of the vehicle acts as an electrostatic fluid accelerator pumping surrounding air as ion wind, radially then downward, so the lower pressure zone on the upper surface and the higher pressure zone underneath the aircraft produces

lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobil ...

and

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that syst ...

for propulsion and stability. At a higher altitude and to reach greater speeds, a

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

is also applied to enhance collisions between electrons and heavy species in the plasma and use the more powerful Lorentz body force to accelerate all charge carriers in the same direction along a radial high speed jet. A very early version of this documented by Jean-Louis Naudin used wire originally from a hard disk drive cable (aka 80/40 wire) with alternate HV on each pair and this works but is very inefficient compared to newer approaches as discussed above.

Novel technologies

To achieve its mission, the WEAV-related research introduced a number of plasma actuator designs. This section highlights the main technologies.

Multi-barrier plasma actuators

The conventional single dielectric barrier discharge (DBD) actuator design is composed of two electrodes separated by a single dielectric material. Much work has gone into optimizing the design and performance of the single DBD design, however research work continues to improve the performance of these actuators. The MBPA design is an extension of the single DBD actuator design which introduces additional dielectric barriers and electrodes, and thus additional design parameters. Research indicates that MBPA designs may achieve higher resultant thrust and improved thrust-to-power ratios than the single DBD actuator design. Sample trials of a bi-layer MBPA design demonstrated an approximately 40% increase in effectiveness over the conventional single layer design.

Serpentine actuators

The WEAV employed serpentine geometry plasma actuators for fully three-dimensional flow control which combine the effects of a linear actuator and plasma synthetic jet. Due to the periodic geometry of the serpentine design, there is pinching and spreading of the surrounding air along the actuator. Consequently, serpentine actuators generate both spanwise and streamwise vorticity, resulting in unique flow structures that are not reproduced by conventional linear geometry plasma actuators.

Micro-scale actuators

Experimental results and numerical simulation demonstrate that by shrinking the gap between electrodes to micron size, the electric force density in the discharge region is increased by at least an order of magnitude and the power required for plasma discharge is decreased by an order of magnitude. Consequently, physically smaller and lighter power supplies can be used with these so-called micro-scale actuators. Investigations demonstrated that per actuator, induced velocities from the micro-scale plasma actuator are comparable to their standard, macro-scale counterparts, albeit with an order of magnitude less thrust. However, due to the decreased power requirements of the micro-scale plasma actuators, experiments suggest effective macroscopic flow control via large arrays of micro-scale plasma actuators.

Novel materials

In addition to experimental plasma actuator designs and geometries, the WEAV investigated the performance of a large variety of insulating materials for use in the dielectric barrier layer, including flexible materials such as silicone rubber and ferroelectric modified lead zirconate-titanate (PZT) and silica aerogel.

Liftoff

An early prototype of the WEAV was able to sustain hovering flight a few millimeters above the ground for approximately 3 minutes. Prototypes of varying radii were also successfully tested, suggesting scalability of the design.

References

External links

WEAV official site
Electric aircraft NASA programs 2000s United States experimental aircraft University of Florida {{aero-2000s-stub