US2546989A - Attitude gyro - Google Patents

Description

Aplrifl 3, 1951 o. E. ESVAL ET AL 5 9 ATTITUDE GYRO Original Filed June 4, 1942 2 Sheets-Sheet l FfiGi 0RD E.E$VAL INVENTORStWALTER WRIGLEY KEN April 9 1951 o. E. EsvAL ET AL 2,546,989

ATTITUDE GYRO Original Filed June 4, 1942 2 Sheets-Sheet 2 lllllll ORLAND E. ESVAL. INVENTORS WALTER WREGLEY ATT RNEY Patented Apr. 3, 1951 ATTITUDE GYRO Orland E. Esval, Huntington, Walter Wrigley,

East Hempstead, and Robert Haskins, Jr., Garden City, N. Y., assignors to The Sperry Corporation, a corporation of Delaware Continuation of application Serial No. 445,760, June 4, 1942. This application December 21, 1945, Serial No. 636,384

1 Claim.

This invention relates to a gyroscopically controlled indicator for aircraft. The invention more particularly relates to a gyro vertical instrument of a type that provides an indication at all times of the, position of the aircraft about its fore and aft axis and its athwartship axis. The instrument provides the pilot with an indication of the attitude of the aircraft through 360 of an inside or outside loop and in a 360 roll. The gyro indicating instrument of the present invention is useful for stunt flying and every conceivable combat maneuver including loops, barrel rolls and combinations thereof. No caging or locking means is required in the improved instrument.

It is an object of the invention to construct a gyro vertical for aircraft in which the pilot obtains an indication of the position of the craft about both its pitch and roll axes at all times.

This application is a continuation of application Serial No. 445,760, filed June 4, 1942, now Patent No. 1,859,208 for Attitude Gyros.

.Other objects of the invention will be more apparent from the following description taken in connection with the accompanying drawings in which a preferred form of the invention is shown.

Fig. 1 is a section through the casing of the gyroscopic indicator or gyro-vertical showing a plan view of the interior parts thereof.

Fig. 2 is a side elevation partly in section of the gyro vertical without the enclosing casing.

Fig. 3 is a front view of the Window of the indicating instrument as seen by the pilot in the position taken by the parts when the aircraft is in level flight.

Fig. 4 is a front view of the window of the indicating instrument in the position taken by the parts when the aircraft is making a right banked climbing turn.

Fig. 5 is a development in reduced size of the indicator proper.

Fig. 6 is a diagram showing the path of an aircraft in making a loop showing the four principal positions thereof.

Fig. '7 is a side elevation of the gyro vertical in the position i of Fig. 6 or when level.

Fig. 8 is a side elevation of the instrument in position 8 of Fig. 6, that is, when making a vertical climb.

Fig. 9 is a side elevation of the gyro vertical in position 9 of Fig. 6, that is, when the aircraft is upside down.

Fig. 10 shows the position of the device in position ll! of Fig. 6, which is a vertical dive.

Figs. 11 through 14 are plan views of the po- 5' sitions with reference to the aircraft of the instrument corresponding to the positions shown in Figs. 7 through 10.

Figs. 15 through 18 illustrate what the pilot sees through the window of the device for each of the positions shown in Figs. 7 through 10.

The gyroscopic attitude indicator of the present invention is provided with a suitable enclosure and support for the working parts of the instrument. The operating parts are, therefore, housed in a casing 26 which ha an opening 2! in the end thereof covered by a transparent member 22 in the form of a window through which the gyroscopic indicator can be viewed. A frame 23 shown as of U-shaped form supports the instrument and secures the same to the casing 20 in any suitable fashion, the frame being shown as bolted to the back of the face plate 29' of the casing 20.

The frame 23 carries bearing means, which provides for the mounting of a gimbal ring 21, in the form of a single elongated sleeve having spaced bearings 26 and 26', Fig. l. The gimbal ring 2! is U-shaped and at the center of the bend in the U, the ring carries a bearing shaft 28 which is journaled in the bearings 26 and 26 and provides the mounting for the major axis of the gyro instrument. Each arm of the U- shaped gimbal rin 27 carries a bearing 36 which receives the trunnions 35 supporting the rotor bearing frame 32 within which the rotor 50, Fig. 2, is journaled for spinning about a substantially vertical axis in bearings 60, 6|. The spherical shell or cover 32 is secured to the trunnions 3i and is free to rotate in the bearings 30 which form the minor or athwartship axi for the gyro instrument. The major axis for the instrument is situated in the casing 28 so that it is substantially parallel to the fore and. aft axis of the aircraft. Preferably the instrument is so mounted in its outer casing that its minor horizontal axis is parallel to the front window 22 and the major horizontal axis perpendicular thereto.

The gyro rotor is supported or mounted within the rotor bearing frame 32 so that its axis is vertical, that is in line with the intersection of the meridian line 33 and the line on opposite sides of the indicating face of the shell. The gyro rotor may :be driven by any suitable means although electrical connections are shown for a three phase electric motor driven rotor to accomplish this purpose.

The cover or shell 32 of the rotor bearing frame 32 is constructed to contain 360 of attitude indications thereupon. The shell or cover 32 paraxis of the instrument and the indications situated on the circumferential surface thereof. Any form of shell having circular symmetry about the athwartship axis of the instrument may obviously be employed in this connection. The center of the surface of the, illustratively employed, spherical indicating cover 32 carries the meridian line 33 and cross-wise thereof are spaced indications which show the angular position or attitude of the aircraft with respect to the vertical spin axis of the gyro rotor 5E The indicia upon the peripheral surface of the indicating cover 32, as shown in Fig. 5, includes a number of parallel arcs having numerical representations that begin at and continue to 90 around the circumference in both directions, i. e., upwardly and downwardly from the horizon reference line. The indicia then decrease from 90 to 0 in both directions and with the numerals inverted. The purpose of this arrangement is to permit normal reading in the event that the gimbal ring should be turned around through 180 when in gimbal lock position in which event the reverse side of the indicator is brought before the window 22 as will hereinafter be more particularly described. With the representations as shown it is immaterial which side of the spherical indicator is before the window. The lower and upper hemispheres provided by the cover 32 are differently colored so that the pilot Will know when he is in upright or inverted position and when he is climbing or diving.

The frame 23 or casing 20 carries a stationary index ring 36 in the front of the same adjacent the window 22. The ring 36 has a roll reference in the form of a scale therein readable with the meridian line to indicate to the pilot the degree of roll (bank) of the craft. As shown, the ring indicator 36 carries an arcuate reference mark or stationary index 3'! such as a wire across the horizontal center of the same. The fixed pitch index 3? is formed of two different colors, one of which contrasts with one of the colors of the spherical cover 32 and the other of which contrasts with the other of the colors of the spherical cover 32. This enables the pilot to obtain a correct indication of the attitude of the craft throughout 360 degrees of movement about its pitch axis. The curve of the bar or wire permits the same to be positioned adjacent the indicating r surface of the spherical case 32. The inner diameter of the ring is made substantially less than the major diameter of the sphere, and it is also preferably slightly less than the minor diameter 3| of the sphere, thus providing a reduced window or mask through which only th central portion of the face of the sphere is visible and the fact that the sphere is truncated is not evident to the observer.

For leading current into the rotor spinning motor, three electric contact rings 4i are carried upon the end of the shaft 28 and each are engaged by a brush connected with a lead in wire 32. A wire 53 from one of the rings ii leads to a flexible contact .5 which establishes an electrical connection with the pointed end of a conductor 55 which in turn connects with the drivmotcr for therotor by means of a suitable lead (not shown)- A like flexible contact 46 establishes connection with the pointed end of a further conductor 4'! for-the gyro motor which contact is electrically connected by a wire 48 to another one of the rings ll. The third connection for the gyro motor is provided by a brush contact 49 which electrically contacts with a conducting sleeve 5 .3 insulated from the conductor 47 which contact is connected by wire 5| with the third of the lead in rings ii. The various contacts and connections described receive current by way of leads 42 from a source (not shown) of three phase current in the present instance.

In operation, with the rotor axis in vertical position, and the aircraft flying level, the indication will be as shown in Fig. 3 with the pitch reference 3'! exactly upon one of the 0 or horizon lines on the surface of the cylindrical indicating shell 32 and the meridian line 33 exactly vertical and in line with the indicia El and I8 on the roll reference scale. If the pilot makes a banked turn to the right the indicating face of the shell 32 maintains its vertical position but casing 20 banks with the plane. The pilot similarly is fixed or stationary relative to the casing and ring 36 and therefore, so far as he is concerned, there is apparently no movement of the ring 36 and the horizon reference line 54 would be inclined but it would intercept the center of the pitch reference bar 3?. Since the horizon line 54, however, as shown in Fig. 4 is above the reference bar 31, the indication shown is a right hand banked turn with the craft climbing.

Relative positions of the casing 29 and generally spherical shell 32 during a loop are shown in corresponding views l-l ll5, 8l2l6, 9i3l and lii--I4l 8. With the aircraft flying horizontally and level, the parts assume the relative positions shown in th first of the noted groups of views. As shown in Fig. 15, horizon reference line 54 is coincident with the stationary pitch reference 31. The scale including portion of the case 32 is subdivided into two segments of 180, each of which are provided with different color backgrounds. The top scale as noted in Fig. 5 is provided with a white background and the bottom scale is contrasted therewith by having a black background. In turn, each of the noted segments is composed of two quadrants having separate scaled indications thereon ranging between 0 and which are arranged in reversed relation. A second horizon reference line is contained on the scale and is indicated at the 0 reference position in Fig. 5 by the reference number 55.

As the craft circles upwardly, it comes to a position 8, in Fig. 6, at which its nose is pointing in a vertical direction. The parts of the instrument then assume the relative positions shown in Figs. 8, 12 and 16. The observer then sees the attitude reference indication ili9li to the rear of the pitch reference 37. In this position, the spin axis of the gyro rotor is momentarily aligned with the ax s of the gimbal ring which is a condition known as gimbal lock. When so situated the rotor does not have its usual biaxial support so that any movement of the craft about a horizontal axis perpendicular to the plane then determined by the axes of the gimbal ring will cause the ring to rotate about its axis. This gimbal rotation is necessary in order to maintain the position in space of the spin axis of the rotor and the tendency of the ring to move in this manner becomes very pronounced when the gimbal lock condition is approached. It is to be understood that this gimbal rotation takes place rapidly as the vertical position is passed through. With the present instrument, it has been practically determined that the position of the gimbal ring is indeterminate when the gyro rotor is in gimbal lock position and following this position the relative parts are arranged in 180 ambiguity. The indeterminate character of the gimbal ring position at this time is due to the fact that the loop maneuver may be so well executed that no rotation of the gimbal ring is necessary to maintain the direction of the spin axis of the rotor. On the other hand, a ring movement of 180 or 360 may be necessary. Because of the 180 ambiguity of the changed gimbal rin position with respect to the gyro rotor, the position of the gyro rotor bearing case rather than the ring is employed in obtaining attitude indications in the present instrument- The reversed relation of the numerical degree representationson the scale will consequentl now be understood. As seen in Fig. 16, the indication obtained from the scale will remain constant regardless of the number of times that the ring rotates since the gyro rotor axis remains vertical. As the craft continues its movement through the loop, the numerical representations of the pitch scale appear upside down with reference to the reference 3'! indicating the fact that the craft is then flying upside down.

At the top of the loop or in position 9, as shown in Fig. 6, the aircraft, casing 20 and observer are upside down with relation to the earth, and the shell or cover 32 and indications thereon maintain the same constancy of position noted in the other views. In this inverted position of the craft, the observer sees the second horizon ref erence line 55 with the dark portion of the scaled rotor bearing case uppermost. The numerical representations also continue to appear inverted.

In the position ll] of the loop, as indicated in Fig. 6, the craft is headin downwardly or diving vertically towards the earth. This position corresponds to the reverse of position 8. The relative locations of the gyroscopic instrument parts are shown in Figs. 10, 14 and 18. This is also a. location of gimbal lock. The observer sees only the white portion of the reference scale and regardless of gimbal lock rotation of the gimbal ring, the numerical representations will appear upright as soon as the craft resumes upright flight. It is evident that the pilot or observer of the instrument sees an attitude indication of the craft in any condition of flight.

In the design of the present instrument, it is necessary to employ a gimbal ring and bearing case of low moment of inertia inasmuch as deviation of the spin axis of the rotor from a vertical position following a gimbal lock condition is proportional to the same.

As schematically shown in Figs. 1 and 2, a control device of the character specifically shown and described in the abandoned application of Orland E. Esval and John R. Muma for Tilt Correcting Devices, filed January 24, 1942, Serial No. 428,140, may be employed to maintain the spin axis of the gyro rotor in an erected position during normal conditions of flight. In this instance, energy may be supplied the selective switch controlled solenoids in the erecting device by way of leads 60, slip rings 6|, two separate lead wires be manually or automatically effected in any of the customary manners of control not known in the art.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

An aeronautic attitude indicator having scalar marking halves with distinctive backgrounds, each half consisting of two quadrants having separate numerals thereon reading from zero to and 90 to zero, and a meridian line dividing said scale, half the marking being on one side of said line and half on the other, the ones on one side being upside down with respect to those on the other side.

ORLAND E. ESVAL. WALTER WRIGLEY. ROBERT HASKINS, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,726,643 Borresen Sept. 3, 1929 2,036,229 Moss Apr. 7, 1936 FOREIGN PATENTS Number Country Date 140,482 Great Britain Apr. 1, 1920 361,330 Germany Oct. 13, 1922 490,127 Germany Jan. 24, 1930

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