Force on an Asymmetric Capacitor 

By Thomas B. Bahder and Christian Fazi 

ARL-TR-3005 June 2003

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Army Research Laboratory 

Adelphi, MD 20783-1197 

ARL-TR-3005 June 2003 

Force on an Asymmetric Capacitor 

Thomas B. Bahder and Christian Fazi 

Sensors and Electron Devices Directorate, ARL 

Approved for public release; distribution unlimited. 
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Force on an Asymmetric Capacitor 

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14. ABSTRACT 

When a high voltage (~30 kV) is applied to a capacitor whose electrodes have different physical dimensions, the capacitor experiences a net 

force toward the smaller electrode (Biefeld-Brown effect). We have verified this effect by building four capacitors of different shapes. The 

effect may have applications to vehicle propulsion and dielectric pumps. We review the history of this effect briefly through the history of 

patents by Thomas Townsend Brown. At present, the physical basis for the Biefeld-Brown effect is not understood. The order of magnitude of 

the net force on the asymmetric capacitor is estimated assuming two different mechanisms of charge conduction between its electrodes: 

ballistic ionic wind and ionic drift. The calculations indicate that ionic wind is at least 3 orders of magnitude too small to explain the 

magnitude of the observed force on the capacitor. The ionic drift transport assumption leads to the correct order of magnitude for the force, 

however, it is difficult to see how ionic drift enters into the theory. Finally, we present a detailed thermodynamic treatment of the net force on 

an asymmetric capacitor. In the future, to understand this effect, a detailed theoretical model must be constructed that takes into account 

plasma effects: ionization of gas (or air) in the high electric field region, charge transport, and resulting dynamic forces on the electrodes. The 

next series of experiments should determine whether the effect occurs in vacuum, and a careful study should be carried out to determine the 

dependence of the observed force on gas pressure, gas species and applied voltage.

15. SUBJECT TERMS

Electrostatic propulsion, capacitor, high voltage, dielectric, ion propulsion, Bieheld-Brown effect, thermodynamics, force, electric 

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Thomas B. Bahder 

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iii

Contents 

List of Figures iv

Acknowledgments v

1. Introduction 1

2. Biefeld-Brown Effect 1

3. Preliminary Experiments at ARL 7

4. Previously Proposed Explanations for the Biefeld-Brown Force 11

4.1 Ionic Wind: Force Too Small........................................................................................12 

4.2 The Ion Drift Picture: Scaling Theory of Force ............................................................13 

5. Thermodynamic Analysis of the Biefeld-Brown Force 18

6. Summary and Suggested Future Work 22

7. References 24

Appendix A. Short Patent History Dealing With Asymmetric Capacitors 27

Appendix B. Force on Asymmetric Capacitor in Vacuum 29
iv

List of Figures 

Figure 1. Excerpt from Thomas Townsend Brown British Patent No. 300,311 entitled 

“Method of and Apparatus or Machine for Producing Force or Motion,”issued on 

November 15, 1928...................................................................................................................2 

Figure 2. Excerpt from Thomas Townsend Brown U.S. Patent No. 2,949,550 entitled 

“Electrokinetic Apparatus,” issued on August 16, 1960............................................................2 

Figure 3. Excerpt from Thomas Townsend Brown U.S. Patent No. 2,949,550 entitled 

“Electrokinetic Apparatus,” issued on August 16, 1960............................................................4 

Figure 4. Figure excerpt from Thomas Townsend Brown U.S. Patent No. 2,949,550 entitled 

“Electrokinetic Apparatus,” issued on August 16, 1960............................................................5 

Figure 5. Excerpt from Thomas Townsend Brown U.S. Patent No. 3,018,394 entitled 

“Electrokinetic Transducer,” issued on January 23, 1962.........................................................6 

Figure 6. Excerpt from Thomas Townsend Brown Patent No. 3,187,206, entitled, 

“Electrokinetic Apparatus,” issued on June 1, 1965..................................................................6 

Figure 7. Our first attempt at making an asymmetric capacitor (a “lifter”), according to the 

specifications given by J. Naudin (1) on Internet Web site <http://jnaudin.free.fr/> ................8 

Figure 8. The second attempt at making a lighter asymmetric capacitor .......................................8 

Figure 9. Flat-shaped (or wing-shaped) asymmetric capacitor used to test whether closed 

electrode geometry is needed.....................................................................................................9 

Figure 10. The capacitor consisting of a single wire. No bias applied ........................................10 

Figure 11. The wire capacitor showing displacement from the vertical (35 kV applied) .............11 

Figure 12. Schematic diagram of the side view of electric field for the asymmetric capacitor 

in Figure 9................................................................................................................................14 
v

Acknowledgments 

T. Bahder thanks W. C. McCorkle, Director of U.S. Army Aviation and Missile Command, for 

the suggestion to look at the physics responsible for the net force on an asymmetric capacitor. 

The authors wish to thank Jean-Louis Naudin (JLN Labs) for his permission to reproduce the 

letter of Thomas Townsend Brown in Appendix B. T. Bahder is grateful for personal 

correspondence with Jean-Louis Naudin (JLN Labs). 
vi

INTENTIONALLY LEFT BLANK. 
1

1. Introduction 

Recently, there is a great deal of interest in the Biefeld-Brown effect, i.e., when high voltage 

(~30 kV) is applied to the electrodes of an asymmetric capacitor, a net force is observed on the 

capacitor. By asymmetric, we mean that the physical dimensions of the two electrodes are 

different, i.e., one electrode is large and the other small. According to the classical BiefeldBrown effect (see Brown’s original 1960, 1962, and 1965 patents cited in Appendix A, and a 

partial reproduction in section 2), the largest force on the capacitor is in a direction from the 

negative (larger) electrode toward the positive (smaller) electrode. Today, there are numerous 

demonstrations of this effect on the Internet in devices called “lifters,” which show that the force 

on the capacitor exceeds its weight (1). In fact, these experiments indicate that there is a force on 

the capacitor independent of polarity of applied voltage. In the future, the Biefeld-Brown effect 

may have application to aircraft or vehicle propulsion, with no moving parts. At the present 

time, there is no accepted detailed theory to explain this effect, and hence the potential of this 

effect for applications is unknown. The authors are aware of only two reports (2) and theoretical 

papers that address such issues (3, 4). 

In section 2, we describe the history of the Biefeld-Brown effect. The effect of a net force on an 

asymmetric capacitor is so surprising that we carried out preliminary simple experiments at the 

U.S. Army Research Laboratory (ARL) to verify that the effect is real. The results of these 

experiments are described in section 3. Section 4 contains estimates of the force on the capacitor 

for the case of ballistic ionic wind and drift of carriers across the capacitor’s gap between 

electrodes. In section 5, we present a detailed thermodynamic treatment of the force on an 

asymmetric capacitor, assuming that a nonlinear dielectric fluid fills the region between 

capacitor electrodes. Section 6 is a summary and recommendation for future experimental and 

theoretical work. 

2. Biefeld-Brown Effect 

During the 1920s, Thomas Townsend Brown was experimenting with an x-ray tube known as a 

“Coolidge tube,” which was invented in 1913 by the American physical chemist William D. 

Coolidge. Brown found that the Coolidge tube exhibited a net force (a thrust) when it was turned 

on. He believed that he had discovered a new principle of electromagnetism and gravity. Brown 

applied for a British patent on April 15, 1927, which was issued on November 15, 1928 as Patent 

No. 300,311, entitled, “Method of Producing Force or Motion.” The patent and its figures clearly 
2

describe Brown’s early work on forces on asymmetric capacitors, although the electromagnetic 

concepts are mixed with gravitational concepts (Figure 1). 

Figure 1. Excerpt from Thomas Townsend Brown 

 British Patent No. 300,311 entitled 

 “Method of and Apparatus or Machine for 

 Producing Force or Motion,” issued on 

 November 15, 1928. 

The discovery of the Biefeld-Brown effect is generally credited to Thomas Townsend Brown. 

However, it is also named in honor of Brown’s mentor, Dr. Paul Alfred Biefeld, a professor of 

physics and astronomy at Denison University in Granville, Ohio, where Brown was a laboratory 

assistant in electronics in the Department of Physics. During the 1920s, Biefeld and Brown 

together experimented on capacitors. 

In order to find a technical description of the Biefeld-Brown effect, we performed a search of the 

standard article literature and found no references to this effect. It is prudent to ask whether this 

effect is real or rumor. On the other hand, the Internet is full of discussions and references to this 

effect, including citations of patents issued (1), see also Appendix A. In fact, patents seem to be 

the only official publications that describe this effect. 

On July 3,1957, Brown filed another patent entitled “Electrokinetic Apparatus,” and was issued a 

U.S. Patent No. 2,949,550 on August 16, 1960. The effect in this patent is described more 

lucidly than his previous patent No. 300,311, of November 15, 1928. In this 1960 patent, 

entitled “Electrokinetic Apparatus,” Brown makes no reference to gravitational effects (Figure 

2). 

Figure 2. Excerpt from Thomas Townsend Brown U.S. 

 Patent No. 2,949,550 entitled “Electrokinetic 

 Apparatus,” issued on August 16, 1960. 
3

The claims, as well as the drawings in this patent, clearly show that Brown had conceived that 

the force developed on an asymmetrical capacitor could be used for vehicle propulsion. His 

drawings in this patent are strikingly similar to some of the capacitors designs on the Internet 

today. In this 1960 patent, entitled “Electrokinetic Apparatus,” Brown gives the clearest 

explanation of the physics of the Biefeld-Brown effect. Brown makes several important 

statements, including: 

• the greatest force on the capacitor is created when the small electrode is positive, 

• the effect occurs in a dielectric medium (air), 

• the effect can be used for vehicle propulsion or as a pump of dielectric fluid, 

• Brown’s understanding of the effect, in terms of ionic motion, and 

• the detailed physics of the effect is not understood. 

In the following, we reproduce Brown’s first two figures and partial text explaining the effect 

(Figures 3 and 4). 

Soon after Brown’s 1957 filing for the patent previously mentioned, on May 12, 1958, A.H. 

Bahnson Jr. filed for an improved patent entitled “Electrical Thrust Producing Device,” which 

was granted a U.S. Patent No. 2,9587,90 on November 1, 1960. 
4

Figure 3. Excerpt from Thomas Townsend Brown U.S. Patent No. 2,949,550 entitled 

 “Electrokinetic Apparatus,” issued on August 16, 1960. 
5

Figure 4. Figure excerpt from Thomas Townsend Brown U.S. Patent 

 No. 2,949,550 entitled “Electrokinetic Apparatus,” issued on 

 August 16, 1960. 

On July 3, 1957, Brown filed another patent (granted on January 23, 1962, as U.S. Patent No. 

3,018,394) for an “Electrokinetic Transducer.” This patent deals with the inverse effect, i.e., 

when a dielectric medium is made to move between high voltage electrodes, there is a change in 

the voltage on the electrodes. (This is reminiscent of Faraday’s law of induction.) Quoting from 

the 1962 patent by Thomas Townsend Brown (Figure 5): 

Until this time, the net force on an asymmetric capacitor was reported as occurring when the 

capacitor was in a dielectric medium. On May 9, 1958, Brown filed for another patent 

(improving upon his previous work) entitled “Electrokinetic Apparatus.” The patent was issued 

on June 1, 1965 as Patent No. 3,187,206. The significance of this new patent is that it describes 

the existence of a net force on the asymmetric capacitor as occurring even in vacuum. Brown 

states that, “The propelling force however is not reduced to zero when all environmental bodies 

are removed beyond the apparent effective range of the electric field.” Here is a quote from the 

patent (Figure 6). 
6

Figure 5. Excerpt from Thomas Townsend Brown U.S. Patent 

 No. 3,018,394 entitled “Electrokinetic Transducer,”

 issued on January 23, 1962. 

Figure 6. Excerpt from Thomas Townsend Brown Patent No. 3,187,206, 

 entitled, “Electrokinetic Apparatus,” issued on June 1, 1965. 
7

In this patent, Brown reports that the asymmetric capacitor does show a net force, even in 

vacuum. However, at present, there is little experimental evidence, except for two reports (2), 

which do not explain the origin of the observed force and two theoretical papers (3, 4). If the 

Biefeld-Brown effect is to be understood on a firm basis, it is imperative to determine whether 

the effect occurs in vacuum. Enclosed in Appendix B, is Bahder’s email correspondence with 

J. Naudin, where Naudin quotes from a letter by Thomas Townsend Brown, who discusses the 

effect in vacuum. 

The main question to be answered is as follows: what is the physical mechanism that is 

responsible for the net force on an asymmetric capacitor? The answer to this question may 

depend on whether the asymmetric capacitor is in a polarizable medium (such as air), or in 

vacuum. However, to date, the physical mechanism is unknown, and until it is understood, it 

will be impossible to determine its potential for practical applications. 

3. Preliminary Experiments at ARL 

The Biefeld-Brown effect is reported in many places on the Internet; however, as previously 

mentioned, only two papers exist (3, 4). Therefore, we decided to verify that the effect was real. 

The authors have fabricated three simple asymmetric capacitors, using the designs reported on 

the Internet (1). In all three cases, we have verified that a net force is exerted on the capacitors 

when a high DC voltage is applied to the electrodes. The three asymmetric capacitors that we 

tested had different geometries, but they all had the common feature that one electrode was thin 

and the other very wide (asymmetric dimensions). Also, a suspended wire, representing a 

capacitor with the second electrode at infinity, showed lift. 

Our first model was made by Tom Bahder, and was triangular in shape, which is a typical 

construction reported on the Internet (Figure 7). One electrode is made from thin 38-gauge 

(0.005-mil) wire, and the other electrode is made from ordinary aluminum foil. The capacitor is 

~20 cm on a side, the foil sides are 20 × 4 cm, and the distance of the top of the foil to the thin 

wire electrode is 3 cm. The foil and wire are supported by a balsa wood frame, so that the whole 

capacitor is very light, ~5 g. Initially, we made the balsa wood frame too heavy (capacitor 

weight ~7 g), and later we cut away much of the frame to lighten the construction to ~5 g. We 

found that in order to demonstrate the lifting effect, the capacitor must be made of minimum 

weight. (Typical weights reported on the Internet for the design in Figure 7 are 2.3 – 4 g.) 
8

Figure 7. Our first attempt at making an asymmetric 

 capacitor (a “lifter”), according to the specifications 

 given by J. Naudin (1) on Internet Web site <http://jnaudin.free.fr/>. 

When ~37 kV was applied to the capacitor in Figure 7, the current was ~1.5 mA. The capacitor 

lifted off its resting surface. However, this capacitor was not a vigorous flier, as reported by 

others on the Internet. One problem that occurred was arcing from the thin wire electrode to the 

foil. The thin wire electrode was too close to the foil. We have found that arcing reduces the 

force developed on the capacitor. Also, compared to other constructions, ours was too heavy, 

5 g. We found that a ground plane beneath the capacitor is not essential for the lifting force to 

exceed the capacitor’s weight. 

Consequently, we decided to make a second version of an asymmetric capacitor, using a 

Styrofoam lunch box and plastic drinking straws from the ARL cafeteria (Figure 8). The 

capacitor had a square geometry, 18 × 20 cm. The distance of the thin wire (38 gauge) to the foil 

was adjustable, and we found that making a 6-cm gap resulted in little arcing. When 30 kV was 

applied, the capacitor drew ~1.5 mA, and hovered vigorously above the floor. 

Figure 8. The second attempt at making a 

 lighter asymmetric capacitor. 

A question occurred: Is the toroidal (closed circular) geometry of the capacitor electrodes 

essential to the lifting effect that we have observed? Consequently, Bahder made a flat-shaped, 

or wing-shaped, capacitor as shown in Figure 9. This capacitor was made from two (red) plastic 

coffee stirrers and a (clear) plastic drinking straw to support the aluminum foil. The significance 
9

Figure 9. Flat-shaped (or wing-shaped) 

 asymmetric capacitor used to test 

 whether closed electrode geometry 

 is needed.

of the clear plastic straw was that the foil could be wrapped over it, thereby avoiding sharp foil 

edges that would lead to corona discharge or arcing. The dimensions of the foil on this capacitor 

were 20 × 4 cm, as shown in Figure 9. The distance between the thin wire electrode (38-gauge 

wire) and edge of the foil was 6.3 cm. This capacitor showed a net force on it when ~30 kV was 

applied, drawing ~500 μA. The force on this capacitor greatly exceeded its weight, so much so 

that it would vigorously fly into the air when the voltage was increased from zero. Therefore, we 

have concluded that the closed geometry of the electrodes is not a factor in the net force on an 

asymmetric capacitor. Furthermore, the force on the capacitor always appeared in the direction 

toward the small electrode—independent of the orientation of the capacitor with respect to the 

plane of the Earth’s surface. The significance of this observation is that the force has nothing to 

do with the gravitational field of the Earth and nothing to do with the electric potential of the 

Earth’s atmosphere. (There are numerous claims on the Internet that asymmetric capacitors are 

antigravity devices, or devices that demonstrate that there is an interaction of gravity with 

electric phenomena.) 

The thin wire electrode must be at a sufficient distance away from the foil so that arcing does not 

occur from the thin wire electrode to the foil at the operating voltage. In fact, in our first model, 

shown in Figure 7, the 3-cm gap from the top of the foil to the thin wire electrode was not 

sufficiently large, and significant arcing occurred. We have found that when arcing occurs, there 

is little net force on the capacitor. An essential part of the design of the capacitor is that the 

edges of the foil, nearest to the thin wire, must be rounded (over the supporting balsa wood, or 

plastic straw, frame) to prevent arcing or corona discharge at sharp foil edges (which are closest 

to the thin wire). The capacitor in Figure 7 showed improved lift when rounded foil was put 

over the foil electrode closest to the thin wire, thereby smoothing-over the sharp foil edges. 

Physically, this means that the radius of curvature of the foil nearest to the small wire electrode 

was made larger, creating a greater asymmetry in radii of curvature of the two electrodes. 
10

When operated in air, the asymmetric capacitors exhibit a net force toward the smaller 

conductor, and in all three capacitors, we found that this force is independent of the direct current 

(DC) voltage polarity. 

The detailed shape of the capacitor seems immaterial, as long as there is a large asymmetry 

between the characteristic size of the two electrodes. 

The simplest capacitor configuration consists of a suspended thin wire from the hot electrode of 

the high-voltage power supply, as shown in Figure 10. To observe the wire movement, a small 

piece of transparent tape was attached at the lower end of the thin wire. A suspended thin wire 

(~12 in length) also showed force with ~35 kV and 1-mA current (Figure 9). From a vertical 

position, the wire lifted, as shown in Figure 11 by as much as 30°, once the high voltage 

approached 35 kV. The usual air breakdown hissing sound of the other capacitors was heard 

when current reached ~1 mA. Actually, the wire did not remain suspended, but oscillated back 

and forth ~60° from vertical, and the hissing pitch followed the oscillation period with amplitude 

and frequency changes. Without the piece of tape at the end, the wire did not lift as much and the 

sound was considerably weaker. The piece of tape seems to increase the capacitance and or the 

air ionization. This suspended wire configuration can be viewed also as a capacitor surrounded 

by the ground system located several feet away (metallic benches, floor and ceiling). As in the 

other capacitor experiments, it also did not exhibit a polarity dependence. 

Figure 10. The capacitor consisting of a 

 single wire. No bias applied. 
11

Figure 11. The wire capacitor showing displacement 

 from the vertical (35 kV applied). 

When the asymmetric capacitors have an applied DC voltage, and they are producing a net force 

in air, they all emit a peculiar hissing sound with pitch varying with the applied voltage. This 

sound is similar to static on a television or radioset when it is not tuned to a good channel. We 

believe that this sound may be a clue to the mechanism responsible for the net force. 

4. Previously Proposed Explanations for the Biefeld-Brown Force 

There are two proposed explanations for the Biefeld-Brown force. Both of these have been 

discussed on the Internet in various places. The first proposed scheme is that there exists an 

ionic wind in the high field region between the capacitor electrodes, and that this ionic wind 

causes the electrodes to move as a result of the momentum recoil. This scheme, described in 

section 4.1, leads to a force that is incorrect by at least 3 orders of magnitude compared to what 

is observed. (This scheme also assumes ballistic transport of charges in the atmosphere between 

electrodes of the capacitor, and it is known that instead drift current exists.) 

In section 4.2, we present the second scheme, which assumes that a drift current exists between 

the capacitor plates. This scheme is basically a scaling argument, and not a detailed treatment of 

the force. In this scheme, the order of magnitude of the force on an asymmetric capacitor is 

correct, however, this scheme is only a scaling theory. Finally, in section 5, we present our 

thermodynamic treatment of the force on an asymmetric capacitor. 
12

4.1 Ionic Wind: Force Too Small 

The most common explanation for the net force on an asymmetric capacitor invokes ionic wind. 

Under a high-voltage DC bias, ions are thought to be accelerated by the high potential difference 

between electrodes, and the recoil force is observed on an asymmetric capacitor. A simple upper 

limit on the ion wind force shows that the ion wind effect is at least three orders of magnitude 

too small. Consider a capacitor that operates at voltage V. Charged particles of mass m, having 

charge q, such as electrons or (heavy) ions, are accelerated to a velocity v, having a kinetic 

energy 

mv = qV. 2

2

1 (1) 

The force exerted on an asymmetric capacitor is given by the rate of change of momentum 

,

q

I F = mv (2)

where I is the current flowing through the capacitor gap, and we assume that all the ionic 

momentum, mv, is transferred to the capacitor when the charged particles leave an electrode. 

Also, we assume that none of this momentum is captured at the other electrode. This is a gross 

over-estimation of the force due to ionic effects, so equation 2 is an upper limit to the ionic force. 

Solving equation 1 for the velocity, and using it in equation 2 gives the upper limit on the force 

due to ionic wind 

I. q

mV F

2

1

2















 = (3)

When the force F is equal to the weight of an object, M g, where g is the acceleration due to 

gravity, the force will lift a mass 

.

g

I

q

mV M

2

1

2















 = (4)

If we assume that electrons are the charged particles responsible for force of the ionic wind, then 

we must use mass m = 9.1 × 10–31 kg. Substituting typical experimental numbers into equation 4, 

we find that the ionic wind can lift a mass 

( ) ( )( ) 6 8 10 gram. m 10

1 0 10 A

1.6 10 C

2 9 1 10 kg 40 10 Volt 5

2

3 2

1

-19

31 3

−

− −

= ×

×

















×

× × = .

s

. . M (5) 
13

The typical weight of an asymmetric capacitor is on the order of 5 g, so this force is too small by 

5 orders of magnitude. 

Another possibility is that heavy ions (from the air or stripped off the wire) are responsible for 

the ionic wind. As the heaviest ions around, assume that Cu is being stripped from the wire. 

Using Cu for the ions, the mass of the ions is 63.55 mp , where 63.55 is the atomic mass of Cu 

and mp is the mass of a proton. The weight that could be lifted with Cu ionic wind is then (upper 

limit): 

( )( ) ( )( ) 0 002 gram. m 10

1 0 10 A

1.6 10 C

2 63 55 1 67 10 kg 40 10 Volts

2

3 2

1

-19

27 3

.

s

. . . M = ×

















×

× × =

− −

 (6) 

Again, this value is 3 orders of magnitude too small to account for lifting a capacitor with a mass 

of 3–5 g. Therefore, the ionic wind contribution is too small, by at least 3 orders of magnitude, to 

account for the observed force on an asymmetric capacitor. 

While the force of the ionic wind computed above is too small to explain the experiments in air, 

it should be noted that this effect will operate in vacuum, and may contribute to the overall force 

on a capacitor. 

4.2 The Ion Drift Picture: Scaling Theory of Force 

In the previous section, we computed an upper limit to the force on a capacitor due to ionic wind 

effects. Ionic wind is a ballistic flow of charges from one electrode to the other. Clearly the 

force due to ionic wind is at least three orders of magnitude too small to account for the observed 

force on an asymmetric capacitor (in air). There is another type of classical transport: drift of 

charge carriers in an electric field. In the case of drift, the carriers do not have ballistic 

trajectories, instead they experience collisions on their paths between electrodes. However, due 

to the presence of an electric field, the carriers have a net motion toward the opposite electrode. 

This type of transport picture is more accurate (than ballistic ionic wind) for a capacitor whose 

gap contains air. Drift transport is used by E. Barsoukov (5) to explain the net force on an 

asymmetric capacitor. 

The general picture of the physics is that the positive and negative electrodes of the capacitor are 

charged and that these charges experience different forces because the electric field surrounding 

the capacitor is nonuniform (Figure 12). The electric field surrounding the capacitor is created 

by the potential applied to the capacitor electrodes and partial ionization of air into positive ions 

and electrons. These charge carriers experience drift and diffusion in the resulting electric field. 
14

Figure 12. Schematic diagram of the side view of 

 electric field for the asymmetric capacitor 

 in Figure 9. 

The battery supplies the energy that is dissipated by transport of carriers in the electric field. The 

electric field is particularly complicated because it is the result of a steady state: the interplay 

between the dynamics of ionization of the air in the high-field region surrounding the electrodes 

and charge transport (drift and diffusion of positive and negative carriers) in the resulting electric 

field. 

If the capacitor is surrounded by vacuum (rather than a dielectric, such as ions on air), the net 

force F on the asymmetric capacitor can be computed by the sum of two surface integrals, one 

over the surface of the positive electrode and one over the surface of the negative electrode (6): 

F E dS E dS ,

S S















 = + ∫ ∫ + −

n n 2 2

0 2

1

ε (7) 

where ε0 is the permittivity of vacuum, E is the electric field normal to the conducting electrodes, 

S+ and S– are the positive and negative electrode surfaces of the capacitor and n is the outward 

normal to S+ and S–. The integrals in equation 7 are done over closed surfaces S+ and S–. As 

stated, the complexity of the calculation is contained in computing the electric field E. In section 

5, we give an expression for the net force on the capacitor assuming that it is surrounded by a 

dielectric, such as air. 
15

The electric field around the small wire electrode is much stronger than the field around the foil 

(see Figures 9 and 12). In our experiments, there is a big difference in the radii of curvature of 

the two capacitor electrodes: the thin wire electrode has a radius r1 = 0.0025 in, and the edge of 

the foil has a radius of curvature of r2 = 0.125 in. This difference in curvature leads to an electric 

field with a strong gradient. The ratios of electric fields at the thin wire electrode to that at the 

rounded edge of the foil is inversely proportional to the square of the radii of curvatures: E1/E2 = 

(r1/r2)

2

 ~ 2500. However, the applied voltage is on the order of 30 kV, over a gap of 6 cm, so an 

electric field of magnitude 2500 × 30 kV/6 cm ~ 1 × 107

cm

V would not be supported in air. It is 

clear that screening of the electric field is occurring due to the dielectric effects of charged air 

ions and electrons, as well as polarized air atoms. When a positive high voltage is applied to the 

thin wire electrode of the asymmetric capacitor, ionization of air atoms, such as nitrogen, 

probably occurs first near the thin wire electrode. The ionization of nitrogen atoms leads to free 

electrons and ions near the small electrode. The electron mobility is significantly larger for 

electrons than for nitrogen ions. This can be expected because the current density J = σ E = n e v 

where σ = n e

2

τ / m is the electrical conductivity, n is charge density, τ is the scattering time, 

and the mean drift velocity v = μ E. So the mobility behaves as μ = e τ / m. Because electrons 

are 3 orders of magnitude more massive than ions, it is expected that they are correspondingly 

more mobile. Experimentally, it is found that the electron mobility in air at atmospheric pressure 

and electric field E = 104

 Volt/cm is approximately (7)

. Volt s

cm 620

2

e ⋅ μ = (8) 

The mobility of N2 ions in air is (8)

. Volt s

cm 2.5

2

N2 ⋅ μ = (9) 

Therefore, the physical picture is that in the high field region, the electrons, with their high 

mobility, are swept out by the electric field, toward the thin wire electrode leading to screening 

of the field. The massive (probably positive) ions are less mobile and are left behind in a plasma 

surrounding the thin wire electrode. 

A scaling argument can be made as follows: The lower foil conductor feels a force F of 

magnitude 

, V F Q l = (10)

where Q is the charge on the foil electrode, V is the voltage between the capacitor conductors, 

and l is the length of the gap between thin wire electrode and foil. The charge Q and voltage V 

are quantities that are actually present when screening is taking place. The negative charge on 
16

the foil, –Q, can be approximated in terms of the measured current, I ~ 1mA, by saying that all 

the carriers are swept out in a time t : 

, v Q

t

Q I

l = = (11)

where t is the time for carriers to move across the capacitor gap, l , if they are travelling at an 

average drift velocity, v. Eliminating the charge Q from equations 10 and 11, leads to an 

expression for the net force on the capacitor 

.

v

V F = I (12)

In equation 12, the current I is a measured quantity, the voltage V is on the order of 30 kV, and 

the drift velocity for electrons is (7)

. s

cm 6.2 106

ve = × (13) 

Alternatively, the electron drift velocity, ve , can be expressed in terms of the mobility, μe, given 

in equation 8, and electric field, E. The net force on the asymmetric capacitor is then given by 

, μ μ

l I

E

V F = I = (14)

where we again used E = V / l . Using the value of electron mobility in equation 8, the net force 

becomes 

( )( ) 6.4 10 N.

cm

m 10

Volt s

cm 620

10 A 0.04 m 4

2

2

2

3

−

−

−

= ×





 





















⋅

= = μ

l F I (15) 

The force in equation 15 could lift a mass M 

. . .

g

F M 0 064 gram

s

m 10

6 4 10 N

2

4

= × =

−

 (16) 

The typical asymmetric capacitor has a mass that is 3 orders or magnitude greater. 

Consequently, drift of electrons cannot explain the observed force on the capacitor. 

An alternative to using the value of electron mobility is to use the smaller value of ionic 

mobility. This will lead to a larger force because the force in equation 14 is inversely 

proportional to the mobility. 
17

( )( ) 0.16 N.

cm

m 10

Volt s

cm 2.5

10 A 0.04 m

2

2

2

3

=





 





















⋅

= =

−

−

μ

l F I (17) 

The force in equation 17, due to the drift of nitrogen ions, could lift a mass M : 

. .

g

F M 16 gram

s

m 10

0 16 N

2

= = = (18) 

The force on the capacitor, given in equation 18, is within a factor of 3, assuming a capacitor of 

mass 5 g. 

As alternative derivation of the scaling equation 14, consider the asymmetric capacitor as being 

essentially an electric dipole of magnitude, 

p = p = Ql, (19)

where Q is the charge on one plate and l is the average effective separation between plates. 

When a high voltage is applied to the asymmetric capacitor (assume positive voltage on the thin 

wire and negative on the foil), the high electric field around the thin wire ionizes the atoms of the 

air. There is comparatively little ionization near the foil due to the lower magnitude electric field 

near the foil. The ionized atoms around the foil form a plasma, consisting of charged electrons 

and positively charged ions. The force on the capacitor must scale like 

F = ∇(p⋅E), (20)

where E is the electric field. The gradient operates on the electric field, producing a magnitude 

dE / dx ~ E / l . Using this value in equation 20, together with the size of the dipole in equation 

19, leads to a force on the capacitor 

, v

VI V

v

I ~ V F = Q ⋅ = l

l

l (21)

which is identical to equation 12. 

From the scaling derivations that were presented, it is clear that electron drift current leads to a 

force on the capacitor that is too small. Using the value of mobility appropriate for (nitrogen) 

ions leads to a force whose order of magnitude is in agreement with experiment. 

Note that the force, given by equation 14, scales inversely with the mobility μ. If the ions are 

responsible for providing the required small mobility, then the picture is that the ions are like a 

low-mobility molasses, which provides a large spacecharge to attract the negatively charged foil 

electrode. As soon as the foil electrode moves toward the positive ion cloud, another positive 

ionic cloud is set up around the thin electrode, using the energy from the voltage source. In this 
18

way, the dipole (asymmetric capacitor) moves in the nonuniform electric field that it has created. 

Physically, this is a compelling picture; however, much work must be done (experimentally and 

theoretically) to fill in important details to determine if this picture has any merit. 

5. Thermodynamic Analysis of the Biefeld-Brown Force 

In this section, we present our hypothesis that the Biefeld-Brown force, generated on an 

asymmetric capacitor, can be described by the thermodynamics of a fluid dielectric in an external 

electric field produced by charged conductors. The (partially ionized) air between capacitor 

electrodes is the fluid dielectric. Although the air is partially ionized, we assume that this fluid 

dielectric is close to neutral on the macroscopic scale. The charged conductors are the 

asymmetric electrodes of the capacitor. The battery provides the charge on the electrodes and 

the energy to sustain the electric field in the air (dielectric) surrounding the capacitor electrodes. 

The total system is composed of three parts: the partially ionized air dielectric, the metal 

electrodes of the capacitor and the battery (voltage source) and connecting wires, and the 

electromagnetic field. The battery is simply a large reservoir of charge. The total momentum 

(including the electromagnetic field) of this system must be constant (9): 

constant, Pdielectric + Pelectrodes + Pfield = (22) 

where Pdielectric is the momentum of the fluid dielectric (air in the capacitor gap and surrounding 

region), Pelectrodes is the momentum of the metallic electrodes, wire and battery, and Pfield is the 

momentum of the electromagnetic field. Taking the time derivative of equation 22, the forces 

must sum to zero 

0. field

dielectric + electrodes + = dt

dP

F F (23) 

As far as the electric field is concerned, its total momentum changes little during the operation of 

the capacitor, because the field is in a steady state; energy is supplied by the battery (charge 

reservoir). So we set the rate of change of field momentum to zero, giving a relation between the 

force on the electrodes and the dielectric: 

 . Felectrodes = − Fdielectric (24)

A lengthy derivation based on thermodynamic arguments leads to an expression for the stress 

tensor, σi k , for a dielectric medium in an electric field (6, 10, 11), 

E D , F

~

F

~ ik i k

T ,

ik +

































∂

∂ = − δ

ρ

σ ρ

E

 (25)
19

where the free energy F

~ is a function of the fluid density, ρ, temperature, T , and electric field 

E. The differential of the free energy is given by 

F S dT d d , ~d = − + ζ ρ − D⋅ E (26)

where S is the entropy, D is the electric induction vector, and ζ is the chemical potential per unit 

mass (6). Equation 25 is valid for any constitutive relation between D and E. We assume that 

the air in between the capacitor plates is an isotropic, but nonlinear, polarizable medium, due to 

the high electric fields between plates. Therefore, we take the relation between D and E to be 

D = ε (E)E, (27)

where ε ( ) E is a scalar dielectric function that depends on the magnitude of the electric field, 

E =|E|, the temperature, T, and the density of the fluid, ρ. We have suppressed the dependence 

of ε on T and ρ for brevity. The dielectric function ε (E) depends on position through the 

variables T and ρ and because the medium (air) between capacitor plates is assumed to be nonuniform. Inserting equation 27 into equation 26, we integrate the free energy along a path from 

E = 0 to some finite value of E obtaining 

( ) () , 2

1 , ~ , , ~ 2 F ρ T E = Fo ρ T − ε eff E (28)

where εeff is an effective (averaged) dielectric constant, given by 

( ) , 1 2

0

2 ε ε ξ dξ E

E

eff ∫ = (29)

where ξ is a dummy integration variable. The dielectric constant εeff depends on spatial position 

(because of ε), on T, ρ, and on electric field magnitude E. 

The body force per unit volume of the dielectric, fi , is given by the divergence of the stress 

tensor, 

k

ik

i

x

f ∂

∂ = σ , (30)

where there is an implied sum over the repeated index k. Performing the indicated 

differentiations in equation 30, we obtain an expression for the body force (6, 10, 11)

P ( ) ,T E E ( ) E ,

T ,

f o E

E

ext

2

eff eff

2 eff 2

2

1

2

1

2

1

ε ε ε ρ

ρ

ε

ρ ρ − ∇ + − ∇ +

































∂

∂ = − ∇ + ∇ (31)

where the external charge density is given by div D = ρext. This charge density is the overall 

external charge density in the dielectric, which may have been supplied by the battery, 

electrodes, and the surrounding air. In equation 31, the pressure Po(ρ, T) is that which would be 
20

present in the absence of the electric field. In the case of a linear medium, the dielectric function 

ε is independent of field E, and εeff = ε , which reduces to the result derived by Landau and 

Lifshitz (6) (see equation 15.12). 

The total force on the fluid dielectric, Fdielectric , is given by the volume integral of f over the 

volume of the dielectric, Ω: 

∫

Ω

Fdielectric = f dV (32)

The volume Ω is the whole volume outside the metal electrodes of the capacitor. According to 

equation 24, the net force on the capacitor, Felectrodes, is the negative of the total force on the 

dielectric: 

[ ] ( ) ∫

Ω 













 −

































∂

∂ = E ∇ + ∇ − E − ∇ E dV ,

T ,

F E

E

ext

2 2 eff

eff

2

electrodes 2

1

2

1

2

1

ρ

ρ

ε

ε ε ε ρ (33)

where we have dropped the term containing the gradient in the pressure, assuming that it is 

negligible. Equation 33 gives the net force on capacitor plates for the case where the fluid 

dielectric is nonlinear, having the response given in equation 27. In equation 33, both ε and εeff

are functions of the electric field. Note that the first three terms of the integrand depend on the 

square of the electric field, which is in agreement with the fact that the observed force direction 

is independent of the polarity of the applied bias. 

There are four terms in the force. The first term is proportional to the gradient of the dielectric 

constant, ∇ε. We expect that the dielectric constant has a large variation in between regions of 

low and high electric field, such as near the smaller electrode. We expect that there is a strong 

nonlinear dielectric response due to ionization of the air. The resulting free charges can move 

large distances, leading to a highly nonlinear response at high electric fields. Therefore, it is 

possible that this first term in the integrand in equation 33 has the dominate contribution. We 

expect this term to contribute to a force that points toward the smaller electrode (as observed 

experimentally), and we expect that this contribution is nearly independent of polarity of applied 

bias. 

The second term in the force equation 33 is proportional to the gradient of the product of the 

square of the electric field and the difference in dielectric constants. The difference in the 

dielectric constants, εeff – ε , can be expanded in a Taylor series in E 

− = − ′( )E − ′′( )E + K, 2

eff 0

4

1 0

3

1

ε ε ε ε (34) 
21

where 

( ) , E T , ,E=0





 





∂

∂ ′ =

ρ

ε

ε 0 and 

( ) . E T , ,E=0

















∂

∂ ′′ =

ρ

ε

ε 2

2

0 (35) 

The gradient of the square of the electric field always points toward the smaller electrode, 

independent of the polarity of bias applied to the capacitor. We do not know the sign of the 

dielectric constants ε′ (0) and ε′′ (0). If the air has dielectric properties described by ε′ (0) < 0 

and ε′′ (0) < 0, then this term would contribute to a force toward the smaller electrode (which 

would be in agreement with experiment). Alternatively, the term [( ) ] 2

2

1 ∇ ε eff − ε E may have the 

wrong sign but may be small. This must be determined experimentally by studying the dielectric 

properties of air or other gas. 

The third term in the force equation 33 is difficult to evaluate. It may well be negligible, 

especially compared to the first term (assuming highly nonlinear dielectric response at high 

fields). Alternatively, if the air behaves as a nearly linear dielectric medium, then εeff ~ ε , and 

the dielectric constant of a gas is typically proportional to its density, ε = α εo ρ , where εo is the 

permittivity of free space, and α is a constant. Using these expressions in equation 33 for ε

yields the force on the capacitor electrodes for the case of a linear dielectric fluid: 

( ) F E dV . ∫

Ω 









 = − ∇ − extE 2

electrodes Linear Medium 2

1

ε ρ (36)

For a linear medium, the first term in equation 35 contributes to a force pointing in a direction 

that is opposite to the gradient of the square of the electric field, i.e., it points toward the larger 

electrode (opposite to the experimentally observed force). In order to obtain a net force from 

equation 36 that is oriented toward the smaller electrode, the second term in equation 36 would 

have to dominate, i.e., the net force on the capacitor would be due to external charge effects. 

The magnitude of the external charges (from battery and surrounding air) on the dielectric fluid 

must be determined experimentally. 

If the space between the capacitor plates is filled with a vacuum instead of dielectric, equation 33 

reduces to a force given by 

( ) ∫

Ω

= − , electrodes Vacuum ext F ρ E dV (37) 

where ρext = 0 for vacuum, leading to zero force on the capacitor. 
22

The thermodynamic theory presented here provides a general expression in equation 33 for the 

net force on a capacitor in terms of the macroscopic electric field E. This electric field in 

equation 33 must be determined by a microscopic calculation, taking into account the ionization 

of gas between capacitor plates, and details of charge transport. 

In summary, at the present time, the relative magnitudes of the fours terms in the force 

expression given in equation 33 are unknown. The magnitudes of these terms must be 

determined by constructing a set of experiments designed to determine the field-dependent 

dielectric properties of the fluid (given by ε) surrounding the asymmetric capacitor electrodes. 

These experiments will permit us to verify if the thermodynamic theory presented here can 

explain the magnitude and sign of the observed force. 

6. Summary and Suggested Future Work 

We have presented a brief history of the Biefeld-Brown effect: a net force is observed on an 

asymmetric capacitor when a high voltage bias is applied. The physical mechanism responsible 

for this effect is unknown. In section 4, we have presented estimates of the force on the 

capacitor due to the effect of an ionic wind and due to charge drift between capacitor electrodes. 

The force due to ionic wind is at least 3 orders of magnitude too small. The force due to charge 

drift is plausible, however, the estimates are only scaling estimates, not a microscopic model. 

In section 5, we have presented a detailed thermodynamic theory of the net force on a capacitor 

that is immersed in a nonlinear dielectric fluid, such as air in a high electric field. The main 

result for the net force on the capacitor is given in equation 33. The thermodynamic theory 

requires knowledge of the dielectric properties of the fluid surrounding the capacitor plates. It is 

not possible to estimate the various contributions to the force until we have detailed knowledge 

about the high-field dielectric properties of the fluid. 

More experimental and theoretical work is needed to gain an understanding of the BiefeldBrown effect. As discussed, the most pressing question is whether the Biefeld-Brown effect 

occurs in vacuum. It seems that Brown may have tested the effect in vacuum, but not reported it 

(Appendix B). More recently, there is some preliminary work that tested the effect in vacuum, 

and claimed that there is some small effect—smaller than the force observed in air; see the 

second report cited in reference (2). Further work must be done to understand the effect in 

detail. A set of experiments must be performed in vacuum, and at various gas pressures, to 

determine the force vs. voltage and current. A careful study must be made of the force as a 

function of gas species and gas pressure. In order to test the thermodynamic theory presented 

here, the dielectric properties of the gas must be carefully measured. Obtaining such data will be 

a big step toward developing a theoretical explanation of the effect. On the theoretical side, a 

microscopic model of the capacitor (for a given geometry) must be constructed, taking into 
23

account the complex physics of ionization of air (or other gas) in the presence of high electric 

fields. Only by understanding the Biefeld-Brown effect in detail can its potential for applications 

be evaluated. 
24

7. References 

1. There are numerous references to asymmetric capacitors, called “lifters” on the internet, see 

Web sites: 

 Naudin, J. http://jnaudin.free.fr/ (accessed September 2002). 

 Naudin, J. http://www.jlnlabs.org (accessed September 2002). 

 Optical Multimedia. http://www.soteria.com/brown (accessed September 2002). 

 Transdimensional Technologies. http://www.tdimension.com/ (accessed September 

 2002) 

 American Antigravity. http://tventura.hypermart.net/index.html (accessed September 

 2002). 

2. Stein, W. B. Electrokinetic Propulsion: The Ionic Wind Argument; Purdue University 

Energy Conversion Lab, Hangar #3, Purdue Airport West Lafayette, IN; 

http://foldedspace.com/EKP%20Ionic%20Wind%20Study%20-%20Purdue.doc (accessed 

September 2000); Talley, R. L. Twenty First Century Propulsion Concept; Veritay 

Technology, Inc. NY; report prepared for the Phillips Laboratory, Air Force Systems 

Command, Propulsion Directorate, Edwards AFB CA. 

3. Cheng, S.-I. Glow Discharge as an Advanced Propulsion Device. ASRS Journal 1962, 12, 

1910–1916. 

4. Christenson, E. A.; Moller, P. S. Ion-Neutral Propulsion in Atmospheric Media. AIAA 

Journal 1967, 5 (10), 1768–1773. 

5. Barsoukov, E. http://sudy_zhenja.tripod.com/lifter_theory/ (accessed September 2002). 

6. Landau, L. D.; Lifshitz, E. M. Electrodynamics of Continuous Media, 2nd ed.; Pergamon 

Press: New York, 1984; sections 2, 5, and 15. 

7. Loeb, L. B. Fundamental Processes of Electrical Discharges in Gases. John Wiley and 

Sons: New York, 1939; p 191. 

8. Brown, S. C. Basic Data of Plasma Physics; John Wiley and Sons: New York, 1959; p 62. 

9. Stratton, J. A. Electromagnetic Theory, McGraw-Hill Book Company: New York, 1941; 

p 104. 
25

10. Abraham, M.; Becker, R. The Classical Theory of Electricity and Magnetism, 2nd ed.; 

Hafner Publishing Co. Inc: New York, 1950; p 95. 

11. Stratton, J. A. Electromagnetic Theory, McGraw-Hill Book Company: New York, 1941; 

p.139. 
27

Appendix A. Short Patent History Dealing With Asymmetric Capacitors 

Townsend Brown, T. A Method of and an Apparatus or Machine for Producing Force or Motion. 

GB Patent 300,311, November 15, 1928. 

Townsend Brown, T. Electrokinetic Apparatus. U.S. Patent 2,949,550, August 16, 1960. 

Bahnson, A. H., Jr. Electrical Thrust Producing Device. U.S. Patent 2,958,790, November 1, 

1960. 

Townsend Brown, T. Electrokinetic Transducer. U.S. Patent 3,018,394, January 23, 1962. 

Townsend Brown, T. Electrokinetic Apparatus. U.S. Patent 3,187,206, June 1, 1965. 

Bahnson, A. H., Jr. Electrical Thrust Producing Device. U.S. Patent 3,227,901, January 4, 1966. 

Cambell, J. W. (NASA). Apparatus for Generating Thrust Using a Two Dimensional, 

Asymmetrical Capacitor Module. U.S. Patent 2,002,012,221, January 31, 2002. 

Cambell, J. W. (NASA). Apparatus for Generating Thrust Using a Two Dimensional 

Asymmetric Capacitor Module. U.S. Patent 6,411,493, June 25, 2002. 
29

Appendix B. Force on Asymmetric Capacitor in Vacuum*

Enclosed below is a copy of my email correspondence with Jean-Louis Naudin (JLN Labs) [1], 

who hosts a Web site on “Lifters.” In this correspondence, Naudin quotes a letter, purportedly 

signed by T. Townsend Brown, in which Brown discusses the question of whether an 

asymmetric capacitor has a net force on it in vacuum under high voltage. 

T. Townsend Brown’s letter, as provided by J. Naudin: 

Dear ...., 

You have asked several question which I shall try to answer. The experiments in vacuum were 

conducted at "Societe Nationale de Construction Aeronautique" in Paris in 1955-56, in the 

Bahnson Laboratories, Winston-Salem, North Carolina in 1957-58 and at the "General Electric 

Space Center" at King of Prussia, Penna, in 1959. 

Laboratory notes were made, but these notes were never published and are not availible to me 

now. The results were varied, depending upon the purpose of the experiment. We were aware 

that the thrust on the electrode structures were caused largely by ambiant ion momentum 

transfer when the experiments were conducted in air. Many of the tests, therefore, were directed 

to the exploration of this component of the total thrust. In the case of the G.E. test, cesium ions 

were seeded into the environment and the additional thrust due to seeding was observed. 

In the Paris test miniature saucer type airfoils were operated in a vaccum exceeding 10-6mm 

Hg.Bursts of thrust (towards the positive) were observed every time there was a vaccum spark 

within the large bell jar.- These vacuum sparks represented momentary ionization, principally of 

the metal ions in the electrode material. The DC potential used ranged from 70kV to 220kV. 

Condensers of various types, air dielectric and barium titanate were assembled on a rotary 

support to eliminate the electrostatic effect of chamber walls and observations were made of the 

rate of rotation.Intense acceleration was always observed during the vacuum spark (which, 

incidentally, illuminated the entire interior of the vacuum chamber). Barium Titanate 

dielectrique always exceeded air dielectric in total thrust. The results which were most 

significant from the -standpoint of the Biefeld-Brown effect was that thrust continued, even when 

there was no vacuum spark, causing the rotor to accelerate in the negative to positive direction 

 *

This appendix appears in original form, without editorial change. 
30

to the point where voltage had to be reduced or the experiment discontinued because of the 

danger that the rotor would fly apart. 

In short, it appears there is strong evidence that Biefeld-Brown effect does exist in the negative 

to positive direction in a vacuum of at least 10-6 Torr. The residual thrust is several orders of 

magnitude larger than the remaining ambient ionization can account for.Going further in your 

letter of January 28th, the condenser "Gravitor" as described in my British patent, only showed 

a loss of weight when vertically oriented so that the negative-to-postive thrust was upward. In 

other words, the thrust tended to "lift" the gravitor. Maximum thrust observed in 1928 for one 

gravitor weighing approximately 10 kilograms was 100 kilodynes at 150kV DC. These gravitors 

were very heavy, many of them made with a molded dielectric of lead monoxide and beeswax 

and encased in bakelite. None of these units ever "floated" in the air. 

There were two methods of testing, either as a pendulum, in which the angle of rise against 

gravity was measured and charted against the applied voltage, or, as a rotor 4ft. in diameter, on 

which four "gravitors" were mounted on the periphery. This 4 ft. wheel was tested in air and 

also under transformer oil.The total thust or torque remained virtually the same in both 

instances, seeming to prove that aero-ionization was not wholly responsible for the thrust 

observed.Voltage used on the experiments under oil could be increased to about 300kV DC and 

the thrust appeared to be linear with voltage. 

In subsequent years, from 1930 to 1955, critical experiments were performed at the Naval 

Research Laboratory, Washington, DC.; the Randall-Morgan Laboratory of Physics, University 

of Penna., Philadelphia; at a field station in Zanesvill, Ohio, and two field stations in Southern 

California, of the torque was measured continuously day and night for many years. Large 

magnitude variations were consistenly observed under carefully controlled conditions of 

constant voltage, temperature, under oil, in magnetic and electrostatic shields, not only 

underground but at various elevations. These variations, recorded automatically on tape, were 

statistically processed and several significant facts were revealed. 

There were pronounced correlations with mean solar time, sideral time and lunar hour angle. 

This seemed to prove beyond a doubt that the thrust of "gravitors" varied with time in a way that 

related to solar and lunar tides and sideral correlation of unknown origin. These automatic 

records, acquired in so many different locations over such a long period of time, appear to 

indicate that the electrogravitic coupling is subject to an extraterrestrial factor, possibly related 

to the universal gravitational potential or some other (as yet) unidentified cosmic variable.In 

response to additional questions, a reply of T.T. Brown, dated April, 1973, stated :"The 

apparatus which lifted itself and floated in the air, which was described by Mr Kitselman, was 

not a massive dielectric as described in the English patent.Mr Kitselman witnessed an 

experiment utilising a 15" circular, dome-shaped aluminum electrode, wired and energized as in 

the attached sketch. When the high voltage was applied, this device, althrough tethered by wires 

from the high voltage equipment, did rise in the air, lifting not only its own weight but also a 
31

small balance weight which was attached to it on the uderside. It is true that this apparatus 

would exert a force upward of 110% of its weight. 

The above experiment was an improvement on the experiment performed in Paris in 1955 and 

1956 on disc air foils. The Paris experiments were the same as those shown to Admiral Radford 

in Pearl Harbor in 1950. 

These experiments were explained by scientific community as due entirely to "ion-momentum 

transfer", or "electric wind". It was predicted categorically by many "would-be" authorities that 

such an apparatus would not operate in vaccum. The Navy rejected the research proposal (for 

further research) for this reason. The experiments performed in Paris several years later, 

proved that ion wind was not entirely responsible for the observed motion and proved quite 

conclusively that the apparatus would indeed operate in high vacuum. 

Later these effects were confirmed in a laboratory at Winston-Salem, N.C., especially 

constructed for this purpose. Again continuous force was observed when the ionization in the 

medium surrounding the apparatus was virtually nil.In reviewing my letter of April 5th, I notice, 

in the drawing which I attached, that I specified the power supply to be 50kV. Actually, I should 

have indicated that it was 50 to 250kV DC for the reason that the experiments were conducted 

throughout that entire range. 

The higher the voltage, the greater was the force observed. It appeared that, in these rough 

tests, that the increase in force was approximately linear with voltage. In vaccum the same test 

was carried on with a canopy electrode approximately 6" in diameter, with substantial force 

being displayed at 150 kV DC. I have a short trip of movie film showing this motion within the 

vacuum chamber as the potential is applied." 

Kindest personal regards, 

Sincerely, 

T.Townsend Brown