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nuc1 to 12.24%/f 2z//avasoa " -6.42%-24 t 1 let iPatiented Aug. 17, 1926. 1,596,380 UNITED STATES PATENT OFFICE. FREDERICK G3 AINT SEPSON, OF SEATTLE, WASEENGTON. SPEED AND Cog RSE INDICATOB, FOR CONVEYASC33. Application filed August 4, 1923, Serial To. 355,747. of the insulating arm 2. The arm 2 with its apparatusThis invention for, measuring relates to thea method yelocity, of, and surrounding atmosphere forms the dielectric indicating the direction of motion, of a tier of the condenser of which the plates 1 are restrial body relative to the surface of the the conductors. The arm 2 is attached at 30 5 earth; and, more specifically, embodies its middle point to the revolving shaft 4 of means of determining the rate at which the the electric motor 5. The numeral 11 rep-, yertical component of the earth's magnetic resents two branches of an electrical con field is cut by an electrical conductor which ductor in the form of a wire, or rod, of forms a part of such moving terrestrial Small cross sectional area compared to its 65. o body. length. Inserted in series with the con The object of the invention is to provide ductor 11 is the inductance coil 26. The two a simple, and easily applied, method of as branches of the conductor 11 lie in the same certaining the velocity and its direction rel vertical and horizontal planes. A brush ative, and parallel, to the earth's surface, of holder 12 is electrically attached to each of 70 any conveyance which is capable of carry the outer extremities of the conductor 11. ing such devices as are necessary in the ex A brush 13 is electrically attached to each ercise of this method. A more particular of the brush holders 12. The distance be object of the invention is to provide means tween the brushes 13 is the length of a diam for determining the speed over the surface eter of the circumference formed by the ro- 75 20 of the earth, and the course, of conveyances tation of the condenser plates 1 about the such as aircraft and watercraft. The direc center of the shaft, 4. The relative posi tion in which the conveyance is headed must tions of the condenser plates 1 and the be determined by a compass and the drift brushes 13 are such as to cause each of the angle, or angle at which the conveyance is plates 1 to make electrical contact with each 30 25 actually proceeding relative to the direc of the brushes 13 for a short time interval tion in which it is headed is determined by once during each revolution of the shaft 4. this apparatus thus furnishing the neces The numerals 2 and 29 represent two triode sary information for determining the true electron relay tubes. Each tube consists of COSe. an anode, a hot cathode and a grid elec- 85. 30 These objects are accomplished by pro trode placed between the anode and the viding, on the conveyance, an arrangement cathode, contained in an evacuated chamber in a well known manner. The cathodes of forcesof electrical are generated circuits by, wherein and are electromotive proportion the tubes 2 and 29 are filament conductors all to, the movement of the conveyance in arranged to be heated by an electric car- 90 35 any direction, in a plane substantially paral rent. The terminals of the filaments, which lel to the earth's surface, which is to say, constitute the cathodes, are electrically con at an angle of ninety degrees from the di nected to form two common terminals, and rection of the vertical component of the to the terminals of the electric battery 3i earth's magnetic field, and by providing which supplies the necessary current to heat 95 40 means for measuring such electromotive the filaments. 30 is an electric battery, or forces; all as will be understood from the other generating source of electromotive following description in connection with the force. 24 is an electric current, or electric accompanying drawings. potential, indicating instrument. 28 is a In the drawings Figure 1 illustrates, dia transformer having a primary coil and a 100 45 grammatically, a typical form of my ar secondary coil. The negative terminal of rangement of electrical circuits, and elec the battery 30 is electrically connected to the trical apparatus, on a conveyance. Figure negative terminal of the battery 31 and, 2 shows in perspective one, of many, ways therefore, to the cathodes of the triode tubes . of assembling the various circuits and ap 27 and 29. The positive terminal of the lo 50 paratus, on a conveyance - battery 30 is electrically connected to one Like reference numerals designate like terminal of the primary coil of the trans parts throughout the several views. former 28 the other terminal of which is Referring particularly to Fig. 1, the nu electrically connected to the anode of the meral 1 represents two conductor plates of triode tube 27. The positive terminal of the 10 55 an electrical condenser. The plates 1 are battery 30 is also electrically connected to rigidly attached to the respective extremities one terminal of the instrument 24 the other s 1,596,380 terminal of which is electrically connected The position of the- pointer 17 relative to to the anode of the triode tube 29. The sec the housing 23, and therefore to the con ondary coil of the transformer 28 has one veyance upon which the entire device is of its terminals electrically connected to the mounted, is indicated by a graduated scale cathode of the triode tube 29 and its other 16. The entire device is mounted upon the 70 terminal electrically connected to the grid conveyance in a position wherein the electrode of the triode tube 29. One of the pointer 17, when opposite the center of the terminals of the coil 26 is electrically con graduated scale 16, is pointing in the direc nected to the grid electrode of the triode tion of the head, and has its longitudinal 10 tube 27. The other terminal of the coil 26 dimension parallel to the fore-and-aft is electrically connected to the cathode of center line of conveyance. When the the triode tube 27. - pointer is in this position the conductor 11 The electrical arrangement of triode elec has, therefore, its longitudinal dimension in tron tubes in the circuits herein-before de a position displaced ninety degrees from 5 scribed constitutes a two stage amplifier, of the fore-and-aft center line of the convey 80 a well known kind, which functions in a ance, and consequently, ninety degrees from manner to greatly amplify electrical poten the direction in which the conveyance is tial differences impressed between the grid heading. The device is attached to the con electrode and the cathode of the triode tube veyance in such a manner as to permit the 20 27, as evidenced by similar, but amplified, conductor 11 to lie in a plane substantially potential differences between the terminals parallel to the earth's surface. of the instrument 24. Let it be assumed that the conductor 11 The arrangement of electrical circuits and is moving in a plane parallel to the surface apparatus hereinbefore described in connec of the earth and that its direction of motion 25 tion with Fig. 1, is such that the condenser is perpendicular to its greatest dimension, 90 plates 1 are conductively joined together, that is, to its length. Under such condition by means of the brushes 13, the brush an electromotive force will be generated holders 12, the inductance, coil 26, and the within the conductor, proportional to the conductor 11, twice during each revolution rate at which it cuts the vertical component 30 of the shaft 4. The time intervals during of the earth's magnetic field and a corre which the plates 1 are not conductively sponding electrical potential difference will joined are of equal duration, it being as be established between the outer extremities sumed that the speed of rotation of the of the conductor. It is to be understood motor 5 is constant. that the direction of the motion of the con 35 In Fig. 2 the insulating, or dielectric, arm ductor 11, and its velocity relative to the 10) 2 is in the form of a ring supported by the earth's surface, is that of the conveyance to motor shaft 4. by means of the insulating which it is attached. Let W meters per spider 3. The conductor 11 is enclosed by Second represent the velocity of the con the insulating tube 10. A housing, consist veyance relative to the earth's surface in a ing of the cylindrical wall 7, bottom 6 and plane parallel thereto. If H maxwell per 105 top 8, encloses the rotating condenser hav Square centimeter is the intensity of the ing plates 1 (one only of which is in view yertical component of the earth's magnetic in the figure), driving motor 5 and the con field; L meters the length of the conductor ductor 11. An electron tube amplifier is 11 which cuts the vertical component of the 65 contained in the housing 23. The numeral earth's magnetic field in a direction perpen 10 25 represents the controlling switches for dicular thereto; and E millivolts the differ the amplifier circuits. The conductor 11, ence of electrical potential generated be with its supporting tube 10, may be rotated tween the extreme ends of the conductor 11 through an angle of one hundred and eighty due to the rate at which it cuts such mag 50 degrees, in a plane parallel to the plane of netic field; then 5 rotation of the condenser plates 1, by means of the shaft 14, which is rigidly attached to v10E the insulator block 9, to which the common THL central point of the conductor 11 and insul Care should be exercised in constructing atting tube 10, is also rigidly attached. The the circuit consisting of the conductor 11, 120 shaft 14 is driven by the gear 15, to which brush holders 12, brushes 13, inductance coil it is attached, and which carries the pointer 26 and condenser havin plates 1 to the 17. A worm 18, which engages the gear end that the time interval during which the 15, is supported by bearings 19 and is brushes 13 are in electrical contact with the driven through shaft 20 by means of crank condenser plates 1 shall be of proper dura 21 and handle 22. The pointer 17 is rigidly tion to permit the condenser having plates 1. attached to the gear 15, and therefore to the to be charged, at the moment when electrical shaft 14, with its longitudinal dimension at contact between the brushes 13 and plates. an angle of ninety degrees from, and in a 1 is interrupted, to substantially the same 65 plane parallel to that of the conductor 11. electrical potential difference between its 30 ,696,886 S. lates as that generated in the conductor the velocity, W, of the conveyance as rela 1, due to the rate at which it is cutting the tive to the surface of the earth. ertical component of the earth's magnetic The amplitude of the current in the induc ield, and which exists between the hrushes tance coil 26, and therefore the potential 3 at the moment of such interruption. The difference between its terminals, will become 70 lectrical potential difference, E, between the approximately zero when the condenser, 'ondenser plates 1 is, therefore, of substan having plates 1, has again become charged ially equal magnitude to the electromotive to the electrical potential difference, between orce generated in the conductor 11, but is in its plates, generated by the conductor 11. direction opposing any ele tric current The electrical contact between the brushes produced by such electromotive-force, at the 13 and the plates 1-will then again be inter noment when the electrical contact between rupted, to be re-established when the plates the brushes 13 and plates 1 is interrupted. 1 have rotated through a further angle of Remembering that the condenser, plates 1 approximately one hundred and eighty de are rotating, with substantially constant an grees, and the cycle of events described re 80. 2ular velocity, about the center of their driv peated. . ing shaft 4; it may be seen that when they The differences of electrical pétential com have rotated through an angle of substantial municated to the terminals of the potential, ly one hundred and eighty degrees they are or current, indicating instrument 24 are pro again in electrical contact with the brushes portional to, but are of much greater mag 13. The difference of electrical potential, E, nitude than, the differences of potential im between the condenser plates 1 is now in a pressed upon the grid electrode and cathode direction to assist a current produced by of the triode. tube 27, as has been herein the electromotive force, E, generated in the before explained. As the speed of revolu manner herein-hefore defined, in the con tion of the motor 5 is approximately con- 90 tductor 11. A transient electric current will, stant the instrument 24 ma be calibrated therefore, be established in the circuit con to indicate the velocity, , of the convey sisting of the condutor 11, brush-holders ance directly. 12, brushes 13, inductance coil 26 and con As E is of maximum value for any veloc denser having plates 1; such current hav ity, V, when the conductor 11 is perpen ing a maximum instantaneous value propor dicular to the course of the conveyance, it tional to a transient EE in becomes necessary to adjust the position of the circuit of 2E. This current may, de the conductor 11, as relative to the fore-and pending upon the magnitude of the resist aft centerline of the conveyance, by means of 100 ance of the circuit, relative to the values of the handle 22, to a position where a maxi. the inductance and capacitancet thereof, be mum current, or potential, is indicated by either oscillatory or non-oscillatory. pre the instrument 24. The position of the fer to so proportion the constants of this pointer 17, relative to the graduated scale 16, circuit, as to cause the current therein to will then indicate the course of the convey. be oscillatory. I also prefer to so connect ance relative to its head or the so-calle the terminals of the inductance coil 26 to . drift angle. . the grid electrode and the cathode, respec The intensity of the vertical component of tively, of the triode electron tube 27, as to the earth's magnetic field varies between dif impress the maximum instantaneous poten ferent places' upon the earth's surface,9 as is . well known. Recourse must, therefore, be 10 tial difference existing between the terminals had to charts prepared by various govern of the coil 26. and caused by the current mental agencies with a high degree of ac-. therein, upon the grid electrode and cathode curacy, which show directly, or furnish suf theof thegrid tube, electrode in such to direction,be positive, as potentialto cause ficient information to permit the deriva with respect to the cathode at the instant of tion of, the required value of field intensity 15 such maximum potential difference. at nearly all places upon the surface of The rate of decay in amplitude of the the earth. It should be noted that in the electrical potential, and current, in the cir near vicinity of the earth's magnetic equa cuit discussed is, as is well known, estab tor the intensity of the vertical component 120 lished by the rate at which the energy in of the earth's magnetic field is of insuffi electrical form therein is radiated or is cont cient magnitude for the purposes of this in verted into other forms. The succeeding vention.As a practical ..example of - the application amplitudes of the oscillatory train are, how of this invention, let it be assumed that an ever, funetions of the initial potential an air-ship, in the approximate vicinity of 25 plitude, 2E. As the rate of decay, or decre Seattle, Washington, United States of ment, of the circuit may be made constant, America, is proceeding upon a compass the potential variations impressed upon the course of thirty degrees is indicated by a gridproportional electrode to and the cathode initial ofpotential the tube ampli27 are standard United States Navy mariner's tude, 2E, which in turn is proportional to . compass. After correction for the varia A. 1,598,380 tion of the compass in the given locality, of H other than 0.5 has been used in the and its deviation, a course of one degree is process of calibrating the instrument 24, say apparent. It may be found that the point H=0.3, the value of H=0.5, for the locali er of the instrument 24 is at its maximum ty involved, must be ascertained from a is deflection from the zero point of the in chart, hereinbefore mentioned, and the ve- : strument, when the pointer 17 is adjusted locity indicated by the instrument correct to a position twenty-five degrees to the left, ed by multiplying it by three and dividing. or port, side of the center point of the grad the product so secured by five. uated scale 16. The true course of the air Let it be further assumed that the veloc 10 ship is then three hundred and thirty-six ity, V, of the above example, is ten meters 4 degrees, that is, per second; and that the length of the con (360-(25-1))=336° ductor 11 is fifty centimeters. Then azimuth reading. The velocity, V, of the 5 air-ship, relative to the ground, is directly 10 = 29. and E-25 indicated by the position of the pointer of the instrument 24, which may be calibrated millivolts. The maximum difference of to show such velocity in knots, geograpini electrical potential impressed between the cal miles, or kilometers, per hour, or in any grid electrode and cathode of the triode 20 other system of units desired, provided that tube 27 is, therefore, 2E or 0.5 miilivolts, E a value of H=0.5 (the approximate inten Let it be assumed that the air-ship herein sity in maxwells per square centimeter of discussed, is being driven on the apparent the vertical component of the earth's' mag course of one degree, herein-before men netic field in the locality specified) has been tioned, by its propeller, at a velocity of fif 25 used in the formula : teen meters per second, with respect to the 5 air. Let this velocity be represented by P. 10E Let W represent the component velocity V= imparted to the air-ship, in meters per sec wherein the deflection of the pointer of the ond, relative to the earth's surface, by the 30 instrument 24 is a function of E. If a value wind. Then 6 W = WW2+P2-2WP cos 25° W100+225- (300X.9063), 7.28 meters per second. Let X represent the with respect to the surface of the earth, be angle included between the line of corrected ing thereby ascertained and, if so desired, compass bearing of the ship's head (the ap resolved into such component courses and 9 parent course of one degree) and the line of velocities as may be caused by disturbing 65 direction from which the wind is approach forces. ing. Then - The term “drift' or “drift angle' is used to designate the angle between the direc 7.28 sin X = 10 sin. 25° 4.226 and tion in which the conveyance is headed and 1 X-35° 30'. the actual direction of movement of the con 70 The component, of the true course of the veyance over the earth's surface. The di ship, due to the wind is, therefore, rection in which the conveyance is headed is easily determined by the use of a/com pass, and, when the drift angle is known 1 It is obvious. that the application of my the true course is easily determined. 75 invention not only affords a means of as It is also obvious that many modifica certaining the true course and velocity, tions, or changes, may be made in the shape, with respect to the earth's surface, of air kind and arrangement of the various parts craft as discussed in the above example; without departing from the broad scope of 1. but, also, its use in conjunction with well the appended claims. It is further appar 80 known devices for measuring the velocity ent that other types of amplifying relays of the air-craft, with respect to the air, to may be used in place of the two stage elec gether with the exercise of simple mathe tron tube amplifier herein shown and de matical processes, affords a means of resolv scribed. While I have shown and described 1 ing such true course and velocity into com a particular form and kind of apparatus, S5 ponent courses and velocities due to forces I do not desire to be limited, or restricted, applied to the air-craft by the wind and the in the broad scope of my invention, as de action of their propellers. It may be also scribed in the claims, to any specific struc readily understood that the principles of ture of apparatus or its arrangement in ele- 1: my invention and the method of its use may mentary parts, the assemblage of which 90 be applied with equal facility to the science form the means of accomplishing the pur of navigation of water-craft, or of other poses hereinbefore stated in substantially. conveyances, the true course and velocity, the manner herein described.

y ' .' ', 1,596,380 s Having set forth the nature of my in 6. The method of ascertaining the char vention, and a means of accomplishing the acteristics of motion of a body in a plane purpose thereof, what I claim as new and Substantially parallel to the surface of the usefull-and of my own invention, and de earth, relative to the earth, which consists, 5 sire to secure by Letters Patent is:- in generating electrical potential differences 70 1. The method of ascertaining the charac betyeen points in an electrical gift Cat teristics of motion of a body relative to the ried by said body, said electrical potential earth, in a plane substantially parallel to the differences being, generated by, and propor earth's surface which consists in inducing tional to the velocity of said body relative O an electromotive force proportional to the to the vertical component of the earth's 75 velocity at which the vertical component magnetic field, amplifying said electrical of the earth's magnetic field is cut by said potential differences, and using said ampli body and deducing said characteristics of fied electrical potential differences to find motion from said electromotive force, the the velocity of said body, the bearing of the bearing of the earth's poles with respect to earth's poles with respect to a fixed dimen- 80 a fixed dimension of the body, being known. sion of the body being known. 2. The method of ascertaining the char 7. Devices for a conveyance, yembodying s acteristics of motion of a body, in a plane an electrical conductor arranged on said substantially parallel to the earth's surface, conveyance for movement over the earth's 20 relative to the earth, the bearing of the surface in a plane substantially parallel to 8 earth's poles with respect to a fixed dimen the earth's surface to thereby cut the verti sion of the body, being known, which con cal component of the earth's magnetic field sists in generating an electromotive force whereby electrical potential differences will by cutting the vertical component of the be generated between different points of said 25 earth's magnetic field at the velocity of the electrical conductor and means actuated by body and measuring said electromotive said differences of potential for determining force. . the speed and drift of movement of said 3. The method of ascertaining the charac conveyance. - teristics of motion of a body relative to the 8. Devices of the class described for use 30 earth, in a plane substantially parallel to the on a conveyance, embodying an electrical' surface of the earth, the bearing of the conductor movable with the conveyance in earth's poles with respect to a fixed dimen such a direction as to cut the vertical compo sion of the body being known, which con nent of the earth's magnetic field whereby sists in measuring the electromotive forces differences of electrical potential will be gen generated in an electrical circuit carried on erated between different points of said elec- ' said body, said forces being generated by, trical conductor, means for adjusting said and proportional to the velocity of said body electrical conductor to find the position in relative to the vertical component of the which said differences of electrical poten earth's magnetic field. - tial are of maximum value and means actu 30 4. The El of ascertaining the charac ated by said differences of electrical poten 05 teristics of motion of a moving body, relative tial to cooperate with said first named to the earth, in a plane substantially paral means to determine the speed and drift of lel to the surface of the earth, the bearing movement of said conveyance relative to of the earth's poles with respect to a fixed the earth. 45 dimension of the body being known, which 9. Devices arranged to be carried by a 110 consists in generating electromotive forces, conveyance, movable relative to the earth, proportional to, the rate at which the verti for indicating the movement of said/con cal component of the earth's magnetic field veyance, in a plane substantially parallel is cut by said moving body and utilizing to the surface of the earth, sing 5 5 said electromotive forces to indicate the electrically conductive element carrie y velocity of movement of said body. said conveyance and arranged to cut the ver 5. The method of ascertaining the charac tical component of the earth's magnetic field teristics of motion of a body in a plane sub at the velocity of the conveyance whereby stantially parallel to the surface of the earth, electromotive forces will be generated there 120 55 relative to the earth, which consists in gener: in, and means connected with said electrical ating electrical potential differences between ly conductive element for utilizing said elec points in an electrical conductor carried by tromotive forces to determine the speed and said body, said electrical potential differences drift of movement of said conveyance in said being, generated by, and proportional to, the plane. y . | 125 6. velocity of said body relative to the vertical 10. Devices arranged to be carried by a component of the earth's magnetic field, and conveyance, movable relative to the earth, deducing from said electrical potential dif for indicating the speed and drift of said ferences the velocity of said body, the bear conveyance, in a plane substantially parallel ing of the, earth's poles with respect to a to the surface of the earth, embodying an 65 fixed dimension of the body being known. electrically conductive element arranged to 6 1,596,380

cut the vertical component of the earth's tal plane, and arranged for movement in a 65 magnetic field whereby electromotive forces unipolar magnetic field, an electrical con will be generated therein, means for ad denser, having terminals arranged to make justing said electrically conductive element electrical contact alternately with the ex to find the position in which said electromo tremities of said electrically conductive ele itive forces are of maximum value, and in ment, means for rotatably mounting said con 70 dicating devices connected with said elec denser, and indicating means governed by trically conductive element and arranged the electric current produced in said elec to be actuated by said electromotive forces. trically conductive element in response to O 11. Devices arranged to be carried by a movement of the same in said unipolar mag conveyance, movable relative to the earth, netic field. 75 for indicating the speed and drift of said 15. Apparatus of the class described, em conveyance, in a plane substantially parallel bodying a conveyance, an electrically con to the surface of the earth, embodying an ductive element, means adjustably support electrically conductive element arranged to ing said electrically conductive element on cut the vertical component of the earth's said conveyance, said electrically conductive 80 magnetic field whereby electromotive forces element being caused to cut the vertical com will be generated therein, means for am ponent of the earth's magnetic field by plifying said electromotive forces, and in movement of said conveyance, an electrical 20 dicating devices arranged to be actuated by condenser having terminals arranged to said amplified electromotive forces. make electrical contact alternately with the 85 12. Devices arranged to be carried by a extremities of said electrically conductive conveyance, movable relative to the earth, element, means for rotatably mounting said for indicating the speed and drift of said condenser, means including an electron tube conveyance in a ple substantially parallel relay for amplifying electric current gener to the surface o the earth, embodying an ated in said electrically conductive element, 90 electrically conductive element arranged to and an indicating device arranged to be cut the vertical component of the earth's operated by said amplified electric current. magnetic field and to thereby have differ 16. Apparatus for determining the drift SO ences of electrical potential generated be of a in a plane substantially horizon tween different points thereof, an electrical tal, relative to the surface of the earth, em 95 condenser having terminals arranged to bodying an electrical conductor carried by make electrical connections alternately with the body and arranged to have electrical po said different points of said electrically con tential differences' generated between differ 35 ductive element whereby said condenser will ent points of the same by the movement of be alternately charged and discharged and such body relative to the vertical component 100 an indicating device arranged to be actuated of the earth's magnetic field, means for ad by the electric current produced in said elec justing said electrical conductor in said sub-. trically conductive element. stantially horizontal plane to a position 40 13. Devices arranged to be carried by a wherein the shortest line in said plane join conveyance, movable relative. to the earth, ing said points is substantially at right 105 for indicating the speed and drift of said angles to the path of said body in said plane, conveyance in a plane substantially parallel whereby differences of potential of maxi to the surface of the earth, embodying an mum value are obtained and means for de 45 electrically conductive element arranged to termining the position of said conductor cut the vertical component of the earth's relative to said body when said differences O magnetic field and to thereby have differ of potential are of maximum value. ences of electrical potential generated be 17. In apparatus of the class described an tween different points thereof, an electrical electrical conductor Ed for movement 50 condenser having terminals arranged to in a unipolar magnetic field, and means for make electrical connections alternately with determining differences of electrical poten 15 said different points of said El CO tial generated between points in said elect ductive element whereby said condenser will trical conductor, embodying an electrical be alternately charged and discharged, condenser having terminals arranged to con means for adjusting said electrically con nect electrically with said points of said ductive element to a position in which said electrical conductor and then to reverse said 120 differences of electrical potential are of max electrical connection, and means for meas imum value, and an indicating device ar uring the electric current produced in said ranged to be actuated by the electric current conductor by the discharge and subsequent 60 produced in said electrically conductive ele charge of said condenser in conjunction with ment. the electromotive force generated in said 25 14. Apparatus of the class described, em conductor by its motion in said magnetic bodying an electrically conductive element field. adjustably supported in a normally horizon FREDERICK GRANT SIMPSON.