1 Experimental Stuies an Parametric Moeling of Ionic Flyers Chor Fung Chung an Wen J. Li* Centre for Micro an Nano Systems, Faculty of Engineering The Chinese University of Hong Kong *Contact Author: wen@mae.cuhk.eu.hk Abstract This paper escribes a novel inoor flyer, calle the Ionic Flyer, that oes not contain any mechanical moving parts an uses only high-voltage electrical energy to prouce thrust. Experimental stuies were parametrically carrie out to unerstan the performance of the Ionic Flyers such as the force-to-power ratio at ifferent input voltage. Through the experimental results, we propose a simple moel to explain the physical phenomena that ictates the thrust generation mechanism for the Ionic Flyers. Figure 1 illustrates the basic structure of the Ionic Flyer with the parameters L,, an h represent the total perimeter length, the separation istance between electroes, the raius of the emitteire an the collector height of the Ionic Flyer. Emitter Wire Keywors: Ionic Flyer, Ion-Propulsion, Micro Flyer. I. INTRODUCTION Helicopters an airplanes use the principles of aeroynamic to prouce lift an thrust. Miniaturize helicopters an planes are now wiely use for inoor an outoor surveillance by embeing them with sensors an cameras. These flyers basically contain powerful rotating mechanical parts in orer to move the air aroun them, an this may cause amages to objects or enanger human subjects aroun them. This paper presents a new kin of flyer that oes not require moving mechanical parts to provie thrust. i.e., it uses ionic momentum exchange to provie thrust. We will refer to these flyers as Ionic Flyers in this paper. The Ionic Flyer is basically an asymmetrical capacitohich uses high voltage (usually higher than 1kV) to prouce thrust. It works without moving parts an convert electrical energy irectly to mechanical energy for propulsion. The Ionic Flyers o not contain any angerous rotating components an the working principle is not aeroynamics but probably relate to electrohyroynamics, i.e., its exact operational principles are unknown at this time to the best of our knowlege. A basic Ionic Flyer contains two primary elements that are essential for its proper functioning. They are an emitter an a collector. The emitter is usually a thin wire that is connecte to high voltage. While the collector is typically a plate foil an is connecte to groun. Insulating materials like balsa woo is use to create the frame in orer to isolate the emitteire an the collector foil. Thus, the basic Ionic Flyer can be consiere as a capacitoith two asymmetrical electroes an the air as the ielectric material. The power input shoul be in high voltage in orer to create a high electric fiel between the asymmetric electroes an this is the main requirement of the Ionic Flyers. h L/3 Figure 1. The structure of a basic Ionic Flyer Collector Foil The working principle of the Ionic Flyers is uner investigation. There are two prepositions, the electrohyroynamic effect an the Biefel-Brown effect, which are escribe below. Intereste reaers are urge to rea the information collecte by Mr. Jean-Louis Nauin [1] for the historical evelopments of the Ionic Flyer. A) The Electrohyroynamic Effect [] By applying a high voltage between two electroes with sufficiently ifferent raii of curvature, the electric corona ischarge coul occur. The high electric fiel generate by the emitter causes gaseous ionization an its partial breakown to prouce a high ensity of ions. As a result, ions with the same polarity of the emitter are rifte to the collector an this cause an electric current flow between the emitter an the collector. [] The movement of ions is probably uner high-frequency collision with the electrically neutral air molecules. Momentum transfer from the ions to the air can be assume to take place. Therefore, the Coulomb force acting on the ions becomes an electric boy force on the air molecules [3]. By Newton s thir law, the force acting on the Ionic Flyer is in the upwar irection an this make the Ionic Flyer lift up. 1-444-164-1/7/$5. 7 IEEE
Positive Ions Neutral Air Molecules Figure. The microscopic view between the electroes of the Ionic Flyers. B) The Biefel-Brown Effect The Biefel-Brown effect is a kin of antigravity effect but it cannot be explaine by the conventional physics. It is propose by Dr. Biefel an Dr. Brown aroun the 195 s. They believe that when a strong uneven electric fiel is generate by a evice, there will be an inuce gravitational fiel. The inuce gravitational fiel can interact with the Earth s gravitational fiel an either increase or ecrease its strength. If the inuce gravitation fiel is in the opposite irection an its strength is stronger than the Earth s gravitational fiel, the evice will lift up. This effect can be experimentally stuie by applying high voltage to a capacitor which is place insie a plastic casing to reject the influence of electric win. The weight of capacitor is measure to be reuce as Biefel-Bown effect exists to reuce the gravity strength on the capacitor [4]. We will show in this paper that our Ionic Flyer oes not operate uner the Biefel-Brown principle. II. THE ELECTRICAL MODEL When an electric corona ischarge takes place in the air, space charge will accumulate in the air gap between the two electroes an this will cause the electric current to flow. Thus, an electrical moel was sought for the Ionic Flyers by obtaining their relationship. This is one experimentally by increasing the input voltage at 1kV increments to the Ionic Flyers an recor the conucting current at the same time. The experimental setup is escribe in Figure 3. Ionic Flyer A L=6 mm, =3mm =5um, h=4mm High Voltage input (V) Current input (I) Output Force Coulomb Force Glassman HV EW5R1 Fluke 179 True RMS Multimeter Figure 3. The experimental setup to measure the current-voltage relationship of Ionic Flyers For the ease of explanation, Ionic Flyer A which has L = 6mm, = 3mm, = 5µm an h = 4mm, as shown schematically in Figure 3, is taken as a representative flyer in the following iscussion. The experimental measure current of Ionic Flyer A was plotte with the applie voltage as shown in Figure 4. By using the least square fitting metho, we have evelope a fitting curve I =.1176( V 6.169) which is our propose I-V relationship for Ionic Flyer A. A parametric analysis was performe an a general electrical moel of the Ionic Flyers was etermine an their properties are iscusse below..5.4.3..1 Experimental LAR Fitting: I = C(V-V) C =.1176mA/kV V = 6.169kV Lift-up voltage: 17kV Threshol Voltage: 6kV 6 1 1 16 1 4 6 Figure 4. The variation of corona ischarge current with applie voltage for Ionic Flyer A: experimental points (blue circle), the propose I-V moel I =.1176 ( V 6.169 ) (full line) A) The three stages of Ionic Flyers When the applie voltage in the range of zero to about 6kV (epens on the configuration of the Ionic Flyer), no measurable current is recor by the multimeter. (The minimum measurable current for Fluke 179 True RMS Multimeter is 1µA). The Ionic Flyer is in the insulating stage. Since the electric fiel generate by the Ionic Flyer is not strong enough to break own the air (the break own fiel strength of air is 3kV/cm). The Ionic Flyer in this stage can be consiere as an insulator. Since the power input to the flyer is zero, no force is create. As voltage input becomes greater than 6.169kV (conucting voltage V ), there are measurable current recor by the multimeter. The Ionic Flyer becomes conuctive at this stage (i.e., conucting stage) because the electric fiel strength is strong enough to break own the air between the electroes. The Ionic Flyer is just like an asymmetrical capacitor that have very low capacitance an work uner the breakown voltage of the ielectric material (i.e., air). As the voltage increases, the resistance of the aiill ecrease because there are increasing number of ions that exist in the ielectric material. However, when the voltage input is beyon about 6kV (threshol voltage), the air is about to be totally broken own, noise comes out from the Ionic Flyer an the flowing current becomes fluctuating. Sparking can also be observe between the electroes of the Ionic Flyers. Once this occurs, an ionic path is complete by the positive ions an connecting the positive an negative electroes, making the Ionic Flyer 1-444-164-1/7/$5. 7 IEEE
3 short-circuite. At this moment, a large current is flowing through the Ionic Flyer an the thrust generation will be isable. This is the breakown stage since the Ionic Flyer may be possibly amage by the sparking. The Ionic Flyers can be efine with an operating range that they can work properly. The operating range is efine between the conucting voltage an the break-own voltage (6.169kV to 6kV in this case). At this range, the air between electroes is partially broken own an the Ionic Flyer can fly silently an relatively stable. The lift-up voltage is the minimum voltage input to lift up the Ionic Flyer. For a proper Ionic Flyer, the lift-up voltage shoul be in the range of the operation stage. B) The formulation of I-V characteristic equation The current-voltage relationship can be approximate by a quaric equation. The electrical moel is therefore ( L,, )( V V ) I = f ε (1) where I is the input current in mini-ampere; V is the input voltage in kilovolt; V is the conucting voltage of the Ionic Flyer in kilovolt an f ( L,, ε ) is the current gain to be euce in the next section. III. THE LIFT-FORCE MODEL The basic lift-force moel is one by investigating the power input to the Ionic Flyers an than recor its upwar lift-force. The result can be plotte in a force output vs. power input graph. The experiment was carrie out by applying voltage with 1kV increments to the Ionic Flyehich is connecte by a wire to an aitional weight of 15 gram. The aitional weight is being put on an electronic balance which has resolution of 1mg. The lift-force is represente by the total weight of the Ionic Flyer plus the weight reuction of the aitional weight recor by the electronic balance. The experimental setup is escribe in Figure 5. Ionic Flyer B: L = 1mm = 3mm h=4mm = 5µm Figure 5. The experimental set-up use to measure the output force to power relationship of Ionic Flyers We use the experimental ata from Ionic Flyer B with L=1mm, =3mm, =5µm an h=4mm, to iscuss the formulation of the lift-force moel below. A tripo to hol the Ionic Flyers Wires connecte the Ionic Flyers to the high voltage power supply with OHAUS Scout Pro Balance: With the pan being covere A) Output force is proportional to voltage input The experimental ata of the voltage input an force output fit very well using the linear equation F = 1.19( V 1.9) as shown in Figure 6. The general equation for output force an input voltage can be formulate by F = J V V ) () ( f where F is the lift-force in gram; V is the input voltage in kilovolt; V f is the barrier voltage in kilovolt, i.e., the force generation process begins when the applie voltage is greater than V f,. J is the force gain in gram/kilovolt to be further euce. Force in gram 17 16 15 13 1 11 1 9 Experimental LAR Fitting: F=J(V-V F ) J = 1.19g/kV V f = 1.73kV 1 3 4 5 6 7 9 Figure 6. The variation of lift-force with applie voltage for Ionic Flyer B: experimental points (re circle), the propose F-V moel F = 1.19 V 1.73 (full line) ( ) B) The maximum output force of the Ionic Flyers The maximum force generate by the Ionic Flyer is limite by the maximum power input. Since every Ionic Flyer has a limite threshol voltage, the maximum force output is limite by this threshol voltage. When a voltage greater than the threshol voltage is applie to the flyer, the output force will rop abruptly to zero. All the input energy will be consume in ischarging. C) The formulation of the lift-force moel The lift-force moel of the Ionic Flyer in terms of power input an force output can be formulate by using the electrical moel I = f ( L,, ε )( V V ) that was iscusse in section II. By P = IV, we can get the following equation: ( L,, ) V ( V V ) P = f ε (3) By substitute with equation (), we can formulate the lift-force moel in terms of only power input an force output by the following equation: T T ( L,, )( J F + V )( J F + V V ) P = f ε where P is the power input in Watt; F is the force output in gram; J F is equal to the reciprocal of the force gain J. f f (4) 1-444-164-1/7/$5. 7 IEEE
4 Figure 7 shows the experimental ata an the euce equation of the lift-force moel of Ionic Flyer B with f ( L,, ε ) =.45mA / kv an V =5.64kV, as euce by the electrical moel. From the force-voltage relationship, J=1.19 g/kv an V f =1.73kV. = 3mm h = 4mm = 5µm L=3mm L=6mm L=75mm 4 35 Experimental Lift-force moel: P=.45(J T F+V f )(J T F+V f -V ) L=1mm L=9mm 3 5 15 1 9 1 11 1 13 15 16 17 Lift-Force in gram J T =.9kV/g V f = 1.73kV V = 5.64kV Figure 7. The variation of power input with lift-force for Ionic Flyer B: experimental points (green square), the propose Lift-force Moel P =.45.9F + 1.73.9F + 7.134 (ash line) ( )( ) IV. PARAMETRIC ANALYSIS AND FORMULATION From the previous sections, we have formulate the electrical an lift-force moel of the Ionic Flyers with some unknown parameters an a function that ha to be etermine. In this section, six primitive parameters have been ientifie an experiments were carrie out to test how they affect the performance of the Ionic Flyers. They are 1) the total perimeter length of the Ionic Flyers (L); ) the separation istance between the positive an the negative electroes (); 3) the height of the collector foil (h); 4) the raius of the emitteire ( ); 5) the ielectric permittivity of the ielectric materials (ε); 6) the mobility of ions of the ielectric materials (k). Each of these experiments is one by varying the testing parameter while kept all other parameters consistence. The results can be analyze by investigating the I-V curves an the F-P curves. A) The total perimeter length of the Ionic Flyers We have constructe five Ionic Flyers for this experiment. They all have = 3mm, = 5µm, h = 4mm an the experiments were performe in the CMNS clean room with controlle 5 o C temperature an 4% humiity. The five Ionic Flyers have the perimeter length L = 3mm, 6mm, 75mm, 9mm an 1mm, respectively, as shown in Figure. Figure. Five Ionic Flyers with L=3mm, 6mm, 75mm, 9mm an 1mm 1..9.6.3 5 1 15 5 3 3mm : C=.736, V =6.1 6mm : C=.1176, V =6.169 75mm : C=.9. V =6.1 9mm : C=.1739, V =6. 1mm : C=.45, V =5.64 Figure 9. I-V curves an F-P curves for the Ionic Flyers with L = 3mm, 6mm, 75mm, 9mm an 1mm Base on the experimental result, we can raw the following conclusions. i) Lift-up voltage ecreases as the length increases By comparing the lift-up voltage of each of the Ionic Flyer, we can fin that the lift-up voltage will ecrease as the total perimeter length of the Ionic Flyer increases. As the Ionic Flyers are supplie with the same voltage, the output force will be largeith a larger size flyer, which leas to a lower lift-up voltage. ii) Current is proportional to the length By investigating Figure 9, the flowing current of the Ionic Flyers can be foun to be proportional to its perimeter length an this property can be formulate by I M L ( V ) I ( V ) M i N i = (5) LN where I M an L M are the input current an the total perimeter length of the Ionic Flyer M; I N an L N are the input current an the total perimeter length of the Ionic Flyer N; V i is any voltage input in the operating range. When Ionic Flyers are supplie with the same voltage, the resistance of the Ionic Flyer is inversely proportional to its total perimeter length. The current gain can than be represent by f L,, ε = Lf, ε ( ) ( ) L=6mm 4 L=75mm L=9mm L=1mm 5 1 15 5 3 35 4 45 5 iii) Force to power ratio increases as the length increases By comparing their lift-force moel as shown in Figure 9, the force to power ratio is larger for an Ionic Flyeith longer perimeter length. 1 1 6 1-444-164-1/7/$5. 7 IEEE
5 B) The gap istance of the positive an negative electroes In this experiment, an Ionic Flyeith L = 1mm, = 5µm an h = 4mm, was test for its performance by carrying out the experiments with ifferent electroes separation istance of 3mm, 4mm, 5mm, 6mm an 9mm. Figure 1 shows the I-V curves an the F-P curves of the experimental results. One obvious property is that the current will ecrease as the separation istance increases. The current gain is plotte with the separation istance in Figure 11. The experimental ata can be fitte very well with the curve g ( ) =.7( 1 ), with all other parameters is being constant. By combining the result with the previous experiment, f ( L,, ε ) is equal to L f ( ε ) experiment, four Ionic Flyers with L = 6mm, = 3mm an = 5µm but constructe with h = 3mm, 4mm, 5mm, 6mm, respectively, as shown in Figure 1, were teste. L = 6mm = 3mm = 5µm h =4mm h =3mm h =6mm h =5mm 1..9.6.3 3mm:C=.45,V =5.64 4mm:C=.115,V =5.657 5mm :C=.799,V =6.5 6mm :C=.516,V =6.1 9mm :C=.71,V =6.444 5 1 15 5 3 35 4 45 Figure 1. I-V curves an F-P curve for the Ionic Flyers with = 3mm, 4mm, 5mm, 6mm an 9mm. By investigating the force to power graph, by increasing the electroes separation istance, a higher force-to-power ratio can be obtaine. To raw a conclusion, by increasing the istance, ion generation will be ecrease. But, a higher force-to-power ratio coul be obtaine, an so the thrust is generate more efficiently. Current Gain in ma/kv 3.5 x 1-3 3.5 1.5 Figure 11. The variation of the current gain with electroe s separation istance = 3mm, 4mm, 5mm, 6mm an 9mm. C) The epth of the collector foil 9 =3mm =4mm =5mm 7 =6mm =9mm 6 1 3 4 5 3 4 5 6 7 9 1 Separation Distance in mm In the previous experiment, we consiere the perimeter length of the Ionic Flyers. By increasing the length, the area of the electroes will be increase. Anotheay to increase the area of electroes is by increase the height of the foil. In this 13 1 11 1 Experimental: L = 1mm LAR Fitting : C =(.7)/ Figure 1. Four Ionic Flyers with h = 3mm, 4mm, 5mm an 6mm The electrical an lift-force moels are shown in Figure 13. Obviously, they have nearly the same I-V curve. Also, referring to the Force-to-Power Curve, they also have similar relationship. So, all these moels, although configure with ifferent foil epth, have the same electrical an lift-force moel..7.6.5.4.3..1 h=3mm: C=.174, V =5.77 h=4mm: C=.1176, V =6.169 h=5mm: C=.137, V =6.7 h=6mm: C=.1169, V =5.75 6 9 1 15 1 1 4 7 Figure 13 I-V curves an F-P curve for the Ionic Flyers with h = 3mm, 4mm, 5mm an 6mm D) The raius of the emitteire.5 h=3mm h=4mm h=5mm h=6mm 1 4 6 1 1 16 1 The emitteire playe an importance role in ion generation. Since the electric fiel strength is the strongest aroun the surface of the emitteire, so the raius of the wire is a critical property of the strength of the electric fiel. So, we constructe two Ionic Flyers with their emitteire being ifferent in raius. The two Ionic Flyers both have L = 1mm, = 3mm, h = 4mm. The raius of the emitteires were 5µm an 1µm, respectively. The experimental results showe that they have the same current gain. However, the two curves have a shift in the voltage-axis since they have ifferent conucting voltage. They have ifferent conucting voltage because the electric fiel strength shoul be constant aroun the wires uring ischarge, although they have ifferent raius. This can be explaine by the Peek s equation [5]. One of the most important concepts of the Peek s equation is the corona inception voltage (CIV). CIV represents the require voltage between two 5 4.5 4 3.5 3 1-444-164-1/7/$5. 7 IEEE
6 electroes that can make the air between them to begin break own. So, Ionic Flyers begin to break own the air molecules when the supply voltage reaches CIV:.31 CIV = Gm Eδ 1 + r δ rw w ln where m represent the wire roughness factor; δ is the air ensity factor; is the istance between two wires an is the raius of the wires; an G is a moification factor foires with raius smaller than.5mm. For all of our Ionic Flyers, the wire use is stainless steel polishe wire, so m is equal to one. All the experiments were one in a clean room with stanar temperature an pressure, so δ is equal to one also. E is the stanar break own fiel strength of the air an is equal to 3MV/m. G is the moification factor equal to foires with raius smaller than.5mm. By using the Peek s equation to calculate the CIV for the two wires use in the experiment, we obtaine CIV = 5.113kV an 4.676kV for the 5µm an 1µm wire, respectively. Figure shows their experimental conucting voltage is 5.64kV an 4.434kV respectively. By observing the force to power curve at Figure, we can see that the ata of the two Ionic Flyers nearly coincie. We can conclue by this experiment that the force generation efficiency is not relate to the wire raius. 1.4 1. 1..6.4. 5 11 17 3 6 9 =1um : C =.17, V = 4.134 =5um : C =.45, V = 5.64 Figure I-V curves an F-P curves for the Ionic Flyers with = 5µm an 1µm 13 1 11 1 9 7 = 5um = 1um r w 6 1 13 16 19 5 31 34 (6) L So, the current gain f ( ε ) is a function of the ions mobility an the permittivity of the ielectric meium. However, the etaile formulation is uner investigation an will be reporte in a ifferent paper. V. CONCLUSION This paper presents a novel flying mechanism which uses no moving parts an only electrical energy to prouce lift an thrust. Experimental stuies were carrie out to formulate the current-voltage characteristic equation an the force-to-power equation, which are critical to the unerstaning of the operational principles of the Ionic Flyer. Parametric analysis is further performe to figure out the effects of all primitive parameters that affect the performance of the Ionic Flyers. The force generation process is confirme to be not only Biefel-Brown effect since the irection of the output force is not efine by the irection of the gravitation fiel but in the irection from the collector to the emitter. ACKNOWLEDGMENT We woul like to thank Mr. Chan Cheung Shing of The Chinese University of Hong Kong for his help in the artwork of this paper. REFERENCES [1] The JLN Labs. Available: http://jnauin.free.fr/ [] L.B. Loeb, Electrical Coronas, University of California Press, Lonon, Englan, 1965. [3] J. Batian, F. No.el, S. Lachau, R. Peyrous, J.F. Loiseau, Hyroynamical simulation of the electric win in a cylinrical vessel with positive point-to-plane evice, J. Phys. D: Appl. Phys. 34 (1) 151 154. [4] Musha,T. an Abe,I., Biefel-Brown effect an electro-gravitic propulsion by high Potential electric fiel, Proc. of the 4th JSASS Annual Meeting, JSASS,1993, pp.19-19 (in Japanese) [5] L. Dascalescu, Ionize Gases: Theory an Applicoriom. Toyohashi: TUT Press, 1993. E) The ielectric materials The force generation process of the Ionic Flyers can be ivie into two parts. They are the ion-generation an the ion-transportation in between the electroes. The lifting force generate may be somehow ue to interactions an force offset between the ions an the neutral air molecules in the ielectric meium. The ion-generation process is relate to the permittivity of the ielectric material while the ion-transportation process is relate to the permeability of the ielectric materials. The permittivity of ielectric material can not be moifie because the Ionic Flyers are suppose to work uner atmospheric air to have a wie variety of applications. The permeability is relate to the air pressure an the temperature, an this will affect the ions mobility in the ielectric material. 1-444-164-1/7/$5. 7 IEEE