US1813485A - Controlling means for aeroplanes - Google Patents

Description

July 7, 1931. J. F. cooK. .JR

CONTROLLING MEANS FOR AEROPLANES W i 1 m V... o a Q w .3

dtbupugz July 7, 1931. i J. F. COOK. Jr f 1 CQNTROLLING MEANS FOR AEROPLANES Filed April 19, 1926 v 3 Sheets-Sheet 2 amen cop:

July 7, 1931. J. F. coo JR CONTROLLING MEANS FOR AEROPLANES 3 Sheets-sheet 3 Filed April 19, 1926 attozvlup Patented July 7,1931

UNITED STATES JOHN r. 0001:, an, or nn'rnorr, MICHIGAN CONTROLLING MEAN FOR AEROPLANES Application filed April 19,

This invention relates to controlling means for aeroplanes and has special reference to means whereby the several stabilizing, controlling or directing devices of an aeroplane arc controlled and operated by a single member, which member is arranged to be operated. by movements of the pilot corresponding to the movements which he would naturally make or positions which 11c would naturally take in directing the aeroplane in the desired direction.

The objectof the present invention not only includes the provision of a control mechanism of the character described but also a control mechanism which is particularly adapted for operating the several sections of an aerofoil of the character set forth in my application, Serial Number 735,986 filed September 5, 1924, wherein the several sectionshave bendable or defiectable nose and trailing edge portions adapted to control lateral'stability, camber and angle of incidence to the line of flight, said mechanism being such as to provide differential operationof the parts whereby lateral stability of the aeroplane is secured and change in camber effected without danger of overstressing the deflectable parts. A further object is to provide control mechanism effecting a centralization and combining of controls, tending to simplification and certainty in operation, and to provide certain other new and useful features, all as hereinafter more fully set forth.

With the above and other ends in View, the invention consists in the matters hereinafter set forth and more particularly pointed out in the appended claims, reference being had to the accompanying drawings in which Figure 1 is a partial plan view with parts broken away and parts diagrammatically shown, of an aeroplane illustrative of an application of the present invention;

Fig. 2 is an enlargedlongitudinal section through a central panel of the aerofoil of the aeroplane;

Fig. 3 is a plan view of the control mechamsm;

1926. Serial No. 102,925.

Fig, 4 is a longitudinal vertical section through a differential mechanism;

Fig. 5 is an end elevation of Fig. 4;

Fig. 6 is a perspective detail of an end portion of the differential mechanism with portions broken away and in section to more clearly disclose the construction;

Fig. 7 is a view similar to that of Fig. 5 with the parts shown in a different position to illustrate the operation;,

Fig. 8 is a side elevation of the control mechanism shown in Fig. 3; and

Fig. 9 is an end elevation of the same.

The aerofoil or wing construction disclosed in the accompanying drawings is of the type shown in my above mentioned pending application for patent and is preferably constructed entirely of metal, the spars and ribs being preferably made of alloy steel members, while the sheet plates forming the skin or covering, are preferably of a metallic alloy which is light in weight and of great strength and flexibility WhlCh permits of flexing the nose and trailing edge portions of the aerofoil to change the camber. and incidence and provides for continuity of curvature upon such flexure.

The main supporting members of this aerofoil comprise a front spar 1 and a rear spar 2, connected by a series of ribs 3, said spars and ribs being preferably. of a fabricated construction and each lncluding an upper and a lower chord member. The upper chord member 4 of each rib 3 is continued forwardly of the front spar to which it is secured where it crosses the same and is bent backwardly to form the nose or entering edge of the aerofoil, the free end of this backwardly extending portion of the chord member, being pivotally connected to the end of an operating arm 5 secured upon a shaft 6 mounted in bearing brackets 7 on the front spar 1. A link 8 connects each of these arms 5 to each chord member 4 intermediate the spar and the entering edge of the aerofoil, so that when this bendable or nose portion of the aerofoil is deflected by the turning of the shaft 6 and movement of the arms 5 exertin a pull upon the lower or rearwardly exten g free end of each chord member, the cross sectional contour 9 forming the skin of the aerofoil are continned from the rigid portion of the wing between the spars, over and} around the bendable nose portion with the rearedges of these plates at the free ends of the chord members 4, overlapping the covering for the lower side of the rigid portion of the wing, thus providing a smooth unbroken surface of continuous curvature and which nose portion may be flexed to modify camber and angle of incidence.

These rib chord members 4 are continued rearwardly from the rear spar 2 and thence forwardly from the trailing edge of the aerofoil to a point adjacent said rear spar at the lower side'of the tail or trailing edge portion, to provide flexibility so that the trailing edge portion of the aerofoil may be flexed downwardly to change the angle of incidence of the aerofoil to the line of flight. The ribs forming the support for the external covering or skin 9 of this portion thus comprise the bendable rear portions of the chord members 4 and the bendable portions 10 at the lower side of the tail portion of the aerofoil (see Fig. 2) which portions 10 form continuations of the lower chord members 11 of the rigid portion or body of the aerofoil between the spars, and to flex this tail portion, levers 12 extend rearwardly into the tail opposite each rib and are connected to the flexible chord members 4 and 10 by links 13 and 13a so that upon swinging movement of said levers 12 with the turning movement of the shafts 14 to which they are secured at, their forward ends, said tail portion of the aerofoil will be flexed downwardly. These shafts 14 are tubular and are mounted in bearing brackets 15 on the rear spar 2 and are arranged in longitudinal alignment, each extending outwardly of the aerofoil from a point intermediate its ends above the fuselage (not shown) and the inner end of each shaft is provided with a lever arm 16 extending downward therefrom for turning the shaft. As shown in Fig. 1, the entire aerofoil or wing is divided into separately operable panels or sections, the main panels 17 having adjacent inner ends substantially meeting in the vertical central longitudinal plane of the fuselage and ex tending laterally therefrom in opposite directions, an equal distance and the end panels 18 being positioned at and forming the extreme outer ends of the aerofoil. The hollow shafts 14, through the medium of the arms 12 operate the trailing edges or tail portions of the panels 17 and through the medium of arms 19 on the shafts 14 connected by rods 20 to similar arms 21 on the shaft 6, transmit turning movement to said shaft 6 to simultaneously, with the movement of the tail" portion, operate the nose portion of the aerofoil to modify the camber thereof. Extending longitudinally through the hollow shafts 14 are shafts 22 provided at their outer ends beyond the inner panels 17, with lever arms whlch are the saine as the arms 12. and which extend into and are connected to the trailing edge portions of the end panels 18' in the same manner in which said arms 12 are connected to the trailing portions of the inner panels 17, and on the adjacent ends of these shafts 22 are lever arms 23 adjacent the arms 16 on the outer hollow shafts 14. The trailing edge portions of the outer or end panels 18 may, therefore be operated independentl of the like portions of the inner panels 1 and these end panel trailin edge portions may be operated indepen ently of each other to effect lateral stability of the aeroplane during fli ht. Both nose and trailing edge portions 0 the aerofoil may therefore be operated to change its camber and angle of incidence, and the trailin edge portions of the end panels may be in ependently operated to effect lateral balance, said por-' tions of the end panels thus serving the purpose of ailerons, with the added advantage that they have continuous unbroken upper and lower surfaces and are located at the extreme ends of the aerofoil where they are most effective.

Many of the features of the construction and arrangement of the control mechanism which is the subject of the present invention, may be utilized, by a suitable modification of this mechanism, in providing a control for aeroplanes of types other than that shown and above described, and therefore such changes as may be necessary to apply the present invention to such other types or constructions of aeroplanes and which fall within the terms of the claims hereunto annexed, are contemplated.

The control mechanism embodying the present invention is preferably located with- ,the horizontal rudder or elevator, and to be moved laterally from side to side in operating the trailing edge portions of the end panels and effect a movement in opposite directions of the two panels for efl'ectingilateral balance of the aeroplane.- The pilot or driver is thus enabled to control the aeroplane by movements which he would naturally or instinctively make and operation is simplified and made certain.

The hand wheel control shown in detail in Figs. 3, 8 and 9 includes a shaft 24 mounted adjacent one end within a bearing bracket 25 for pivotal movement in a vertical plane, said bracket being mounted upon an upwardly extending steering post 26, the normal position of the wheel shaft being substantially horizontal. On the free end of the shaft 24 is a hand wheel 27 for rotating the shaft and on this shaft within its hearing bracket 25 is a pulley 28 over which is trained a cable 29. The lower end of the steering post 26 is mounted on a frame'30, which frame in turn is mounted for rotative movement, upon suitable trunnions 31 on the frame, which trunnions are mounted in suitable bearings on the framing (not shown) of the aeroplane fuselage. Loosely mounted upon the ends of these trunnions are pulleys 32 over which the cable 29 passes and from these pulleys the cable runs are led rearwardly to the usual rudder (not shown) for steering the aeroplane to the right or left. The steering post is mounted at its lower end for rotative movement upon the frame 30 relative thereto and secured to the lower end of the post are laterally extending arms 33 which turn with the rotation of the post, but do not swing with the forward and rearward rocking of the post about the trunnions 31 as said arms lie in the axis of rotation of said trunnions. An arm 34 (see Fig.

8) extends downwardly from the lower side of the frame 30 to swing forwardly and backwardly with the turning of the frame on its trunnions. The steering post is therefore free to swing forwardly and rearwardly at its upper end and to have a limited rotative movement without changing the length of the cable 29 and thus-effecting the operation of the rudder.

Connected to the lower end of the arm 34 is a rod 35 which extends rearwardly to a suitable connection with the usual horizontal rudder or elevator (not shown) so that in whatever position the wheel may be, the aviator may change the elevation of his machine in flight by simply pushing forward or pullin backward upon the wheel, thus rocking t e steering post forward or'backward and swinging the arm 34 to change the angle of the elevator, and these are movements which he would naturally make when wishing to ascend or descend.

A--'differential mechanism which is indicated' as a whole by the numeral 36 includes ahollow shaft 37 which is mounted to turn in suitable bearings indicated 38 in Figs. 3

and 4, and which bearings are upon the aeroplane fuselage framing (not shown) adjacent the drivers seat and preferably arranged transversely of the fore and aft central plane of the aeroplane so, that connec tions may be conveniently made between it and the arms 33 on the steering post, and also between it and the arms 16 and 23 on the inner ends of the shafts 14 and 22 respectively. This shaft 37 is provided with a hand lever 39 at oneend by means ofdifferential from the steering post by the pivotal movement of the post when the hand wheel shaft 24 is swung laterally, or from side to side. Other and downwardly extending arms 44 are secured directly to the shaft 37 adjacent the ends of the differential mechanism and to the lower ends of these arms rods 45 are connected at one end, their opposite ends being connected to the free ends of the arms 16, which arms are secured to the inner ends of the hollow shafts 14 for operating the tail portions of the wing sections or panels 17. Operated by the differential mechanism are arms 46 extending downwardly from said mechanism and connected by rods 47 to the lower ends of the arms 23 on the adjacent ends of the shafts 22 which operate the tail portions of the two end sections or panels 18. The diflerentialmechan'ism may, therefore be operated by either the hand lever 39 or the lateral swinging movement of the hand wheel 27, and this mechanism is connected to the shafts 14 and 22 so that motion will be transmitted to said shafts from said mechanism for changing the camber and angle of incidence, and efiecting lateral balance of the aerofoil.

When the hand lever 39 is moved to anyposition of adjustment, both inner panels 17 and both end. panels 18 receive identically the same movement and the camber and angle of incidence of all panels is changed equally, and this is, accomplished by means ofthe differential mechanism '36 which is shown in detail in Figs. 4, 5 and 6, which mechanism includes a sleeve 48 secured to the ,shaft 37 and provided with right and left hand external threads 49 to engage the two internally threaded nuts ,50 and 51' thereon and the ward or down turned position with its latch 41 engaging the lowest notch in the section 40, said nuts being prevented from turning With the shaft 37 when said shaft is turned by means of the lever, by a spline or rib 52 011 a fixed bracket 53 engaging a groove in said nuts. When the hand lever 39 is swung from its position in engagement with the lower notch of the sector to engagement with the upper notch thereof, or through an angle approximating seventy five degrees, the nuts 50 and 51-are caused to move airially and longitudinally in opposite directions and movement of said 'nuts causes a similar movement of helically splined sleeve members 54, each of which is connected with an adjacent nut to move longitudinally therewith but free to rotate independently thereof. Each of these sleeve members has inner helical splines or threads 55 and outer helical threads or splines 56 with the helix'of one running opposite to that of the other, mak ing right and left hand helices with the outer splines 56 engaging corresponding splines on the inner side of a pair of cylindrical drums 57 and 58 which drums are sleeved over and form a casing for the nuts 50 and 51 and the .splined sleeves 54, with the inner ends of said drums in abutting relation and the drums free to turn relative to said nuts, sleeves and the shaft 37 but held against longitudinal movement. The arms or levers 43 are secured to the outer ends of the drums-57 and 58 and are held against turning, except relatively, by the rods 42 which connect them with the arms 33 on the steering post 26, so that said drums cannot turn except with the turning of said steering post when the steering wheel 27 is swung from side to side and then can turn relatively in opposite directions only, ball joint connection between the ends of said rods and, said arms 33 and 43 being provided to provide for the relative angular movement of said arms and rods. When the helically splined sleeves 54 are moved longitudinally by the longitudinal movement of the nuts 50 and 51, said sleeves will also be rotated by the engagement oftheir outer splines 56 with the corresponding inner splines on the drum or casing parts 57 and 58 and the inner splines 55 on said sleeves will, by their engagement with corresponding splines on inner sleeve members 59 and 60, impart to said inner sleeves a limited rotation upon the shaft 37 and to the arms 46 which are secured to the outer ends of said sleeves 59 and 60, which ends project beyond the ends of drum parts 57 and 58 and are held against longitudinal movement upon the shaft 37 by abutting the bearings38 at their outer ends, the said drum parts 57 and 58 being held against longitudinal movement by abutting at their outer ends, collars-61 on the inner sleeves 59 and 60, which collars carry the arms 46. The inner sleeves 59 and 60 will therefore have an angular or rotative movement relative to the outer drum members 57 and 58, equal to the pitch of both inner and outer splines 55 and 56.

The angular movement of the arms 46 is slightly greater than that of the arms 44, but the linear movement of the rods 45 connected to the arms 44 and which rods operate the inner panels 17, and the rods 47 attached to the arms 46 and which operate the outer panels 18, is the same. Therefore all of the panels of the aerofoil will have the same movement and cross section at all stages of adjustment of the hand lever 39. a

Three controls of the aeroplane are combined in a single control, to wit, the hand wheel 27, in the present control mechanism,-

and the movements to be made by the pilot in controlling the aeroplane by means of this wheel, are those movements which one familiar with the use of a wheel in directing the movements of an automobile, would make. Rotation of the wheel 27 causes rotation of the shaft 24 and pulley 28 which will transmit motion by means of the cable 29 to move the vertical rudder to the right or left. Rearward movement of the wheel 27 will rock the post 26 and swing the arm 34 to operate the horizontal rudder or elevator to cause upward or downward directional movement of the aeroplane. If the wing of the aeroplane tilts downward to the left, the pilot will instinctively move to the right, thus swinging the wheel 27 to the right. This will turn the steering post 24, swinging one arm 33 secured to the lower end of the post, forwardly and the other arm rearwardly. This movement of said arms will rotate, through the medium of the rods 42 and arms 43, the drums 57 and 58, turning them upon the shaft 37, relatively in opposite directions and thus through their spline connections with the inner sleeves 59 and 60, and the consequent relative and opposite swinging of the arms 46 attached thereto, increasing the camber of the left end panel 18 and decreasing the camber of the right panel. Consequently the upward pressure on the left panel will be come greater than that on the right, and the aeroplane will regain its equilibrium.

As previously described, a movement of the hand lever 39 effects a like change of camber in all of the panels, and therefore this hand lever may be set to give an aerofoil of deep camber, low speed and high lift, or an aerofoil of high speed and low lift camber. When the hand lever 39 is in mid position, the arms 44 and 46 will be in vertical position as shown in Fig. 5 and the lateral .movement of the hand wheel will cause an equal but opposite movement of the two end panels, but when. the hand lever 39 is at its most forward or down position as shown in Fig. 8, which is the high speed position, a full movement of the hand wheel to the right will cause an accelerating move- 'ment to the left panel and a decelerating movement to the right panel, and the ex-- tent of movement of the left panel is approximately twice that of the right panel. This differential movement is best illustrated in Fig. 7 where it will be seen that when the lever 39 is in its extreme rearward, vertical or low speed, deep camber, position, the arms 46 will be at A and when the hand wheel 27 is then given a' full right movement, the left arm 46 will be moved to B and the right arm 46 to C. The angular movement of the two levers is the same but it will be seen that the horizontal distance from A to C is approximately twice the distance from A to B, this being the relative linear movement of the rods 45 and 47. This differential movement is reversed when said lever 39 is moved from one extreme position to the other.

As will be obvious from Figs. 5 and 7, the movement of lever 39 to the opposite position to that shown in Fig. 8 (where the lever is in the approximately vertical position) shifts arms 44 and 46 to the opposite side of the vertical from that shown in Fig. 7 in other words, the movement of the lever from the mid position-corresponding to the position of Fig. 5-toward the horizontal, shifts these arms to the right in Fig. 5 (the position of Fig. 7), while the movement of the lever toward the vertical shifts these arms toward the left in Fig. 5, During the shifting of the lever 39, arms 43 .remain unchanged in position, due to the connection thereof to member 33 through connections 42, this latter condition forming one of the reasons for the action of the differential. r

As a result, each end aerofoilnot only has the equal movement to and from the normal position of the trailing edge when lever 39 is in mid position and member 33 is moved to and from the position of Fig. 3,

but each aerofoil also has the condition of movements to and from a normal position in which the magnitude of distance travelled is greater in one direction than the other; for instance, with lever 39 in one of its extremepositions, the swinging movement of member 33 in one direction will cause the trailing edge of one aerofoil to move upward a greater distance from the normal position, than it moves downward from that position when member 33 is moved in the opposite direction from the position of Fig. 8. Should, however, the lever 39 be in its opposite extreme position, this condition would be reversed and the major magnitude of movement would be in the downward direction. -As a consequence, the action of the control mechanism is largely increased in flexibility, and more nearly accords with the best conditions for handling .the plane in flight.

The object of this difi'erential movement is two fold. First, the ribs of the aerofoil are made with their normal cross section approximately midway between the high speed and low speed sections, and are bent each way to the high and low speed sections, and these two sections may be near the maximum safe flexure of the ribs. A full right movement of the control wheel when the wing is in the high speed position, will cause still greater decrease in camber of the right panel, and full right movement of the wheel when the wingis in the low speed position will cause a still greater increase in camber of the left panel, but this differential movement reduces this greater movement, which permits using a cross section for high and low speeds that is closer to the maximum safe flexure of the. ribs, without exceeding the safe flexure when the control wheel is moved to its lateral limit. Second, when the wing is in the low speed position and tilted to its maximum angle for landing, the differential will avoid accidentall exceeding the critical angle at which the li t of the wing falls off.

While this differential arrangement is particularly advantageous when used in connection with an aerofoil of the type and con struction shown, it may be embodied in the control mechanism for other types.

That the hand wheel27 may be causedto i move in a substantially horizontal plane through its forward, backward or lateral movements and thus maintain its position in height relative to the pilots seat, the shaft 24 is provided with an extension 62 as shown 1 justed relative to the post to change the height of the wheel 27 relative to the 'drivers seat.

end panels 18 are under the control oftl'ie hand wheel 27 at all points of adjustment of the hand lever 39, as well as when the lever is being moved, and in the present invention'the're is shown five positions of adjustment of said lever, there being five notches in the quadrant 40 so that the camber of the aerofoil may be adjusted to suit the particular conditions of flight and held in that condition.

' It will be observed that the relative movement of the nose and trailing portions with its smooth and unbroken curves, will cause an increase in lift over the entire surface from the leading to the trailing edge of the aerofoil, and will thus result in keeping the center of pressure at substantially the same position, utilizing the increased lift of the entire area of the end panels for lateral control, reducing the necessary length of the end panels which increases their mean distance or lever arm from the center of gravity of the machine, and reduces the torsion placed on the'wing and avoids overloading of the rear spar, which is the case when ailerons of the usual type are used at the rear edge of the wing with their efficiency reduced by the discontinuity of curvature and gaps in the surface, and their position at the rear of the wing Where the lift is the lowest ofany part of the chord. The effectiveness of such ailerons is also reduced by their comparatively narrow width and greater length, which reduces the mean distance or lever arm from the center of gravity of the machine.

Having thus fully described my invention, what I claim is 1. A control mechanism for air craft including a control instrumentality operable to-effect movements of similar magnitude of the trailing edge portions of an aerofoil adjacent the two wing ends, and a second con trol member operable at will to cause the movement of the instrumentality to effect relative trailing edge movements differing as to magnitude in the several edge portions, the direction of major magnitude movement of a trailing edge to and from a normal position being selectively above or below such normal position, the movement of the instrumentality being similar in characteristic under both conditions.

2. In combination with an aerofoil, the camber of which may be changed at will, of control mechanism including a member for effecting a like change of camber of both end portions of the aerofoil, and an instrumentality for effecting a change in camber of similar or of differing magnitude of the end portions of the aerofoil relatively to each other at will, the similarity or differential inmagnitude being determined by said member, the direction of major magnitude movement of an end member to and from a normal position being selectively above or below such normal position.

3. 'A control mechanism for air craft including a control member operable to effect movements of similar magnitude of the trailing edge portions of an aerofoil adjacent the two wing ends, a second control member operable to effect movements differing as to magnitude of said portions relatively to each other, and differential means operatively connected with both of said members and active in transmitting the motions of said members to the trailing'edge portions under either of said conditions, the direction of major magnitude movement of a trailing edge to and from a normal position being selectively above or below such normal position.

4. A control mechanism for air craft having wings provided with deflect-able nose and trailing edge portions, said mechanism including a control instrumentality operable to effect altitudinal and directional movements and lateral balance of the air craft, a second control instrumentality operable to effect a change in wing camber, and differential means opcratively' connected to said control instrumentalities for effecting a change in camber of nose and trailing edge portions of 'said wings when operated by saidsecond operating member and to effect relative movements of said nose and trailing edge portions of one Wing and said portions of the other Wing of similar or of differing magnitude when operated by said first control instrumentality, said second control instrumentality being active to determine such similarity or differential in magnitude conditions, the direction of major magnitude movement of a trailing edge to and from a normal position being selectively above or below such normal position. v

5. A control mechanism for air craft having wings provided with deflectable nose and trailing edge portions, said mechanism including differential means operable to effect movements of similar magnitude or differing in magnitude at will of said portions of opposite wings, the direction of major mag- I nitude movement of a trailing edge portion to and from a normal position being selectively above or below such normal position.

6. A control mechanism for a cambered aerofoil having bendable nose and trailing edge portions, said mechanism including means for effecting a bending movement of similar magnitude or differing in magnitude at will of said portions in opposite directions, the direction of major magnitude movement of a trailing edge portion to and from a normal position being selectively above or below such normal position.

7. A control mechanism for air craft including an upright member pivotally supported for movement on two independent axes to ermit a fore and aft swinging movement of its upper end and a pivotal movement axially, a member pivotally supported upon the upper end of said upright member and rotatable relative thereto, a hand wheel on said pivotally and rotatively supported member, means operated by the turning movement of said wheel to control directional movement of the air craft, means operated by the fore and aft movement of the upright member to control an elevator, and

means including the upright member and operated by a lateral swinging movement of manually operable control menibefifiFim parting movement to said differential means, said differential means being operative to change the wing camber and maintain such adjustment thereof by a setting of one of said control members and operative to vary the camber determined by such setting, by a movement of the other of said control mem bers, the setting range of said first control member being effective to permit movement of the second member to provide cambervarying movements of similar magnitude or of differing magnitude in lateral balanc-' ing activities, the direction of major magnitudemovement of the wings to and from a normal position in providing changes in wing camber being selectively above or below such normal position.

9. A control mechanism for air craft including manually operable control members and differential means operated by said control members, said differential means comprising relatively rotatable members each operatively connected to movable portions of an aerofoil to operate the same and eflect a change in camber, said members being operatively connected to effect a differential movement of one of the means members by a rotative movement of the other.'

10. A control mechanism for air craft as set forth in claim 9 and wherein one of said manually operable control members is pro vided with means for holding the same in the position to which it is adjusted and an other of said control members is freely operable. v

11. In control mechanism for air craft, the combination with a single control member having rotating movement to control directional movements of the air craft, for

ward and backward swinging movements to operate the elevator of the air craft, and lateral swinging movements to control lateral balance, of a second control member operative in the camber control of the air mal position being selectively above or below suchnormal position.

12.- As a means for controlling the lateral balancing of airplanes, a single control instrumentality operative to effect directional movements of the plane, movements of the plane elevator, and lateral balancing activities by relative movements ofthe aerofoils, a camber control instrumentality operative at will to effect like movements of wing members' to-producefil tije canrber conditions of the plane, and means witliinthe instrumentality connections and within the control'of both instrumentalities for causing the lateral balancing movements of the aerofoils by single control instrumentality movement to be selectively of similar magnitude 'or of differing magnitudes, the direction of majormagnitudeanovement of an aerofoil in changlng its camber to and from imp mal position being selectively above or below such normal position, whereby selection as to the magnitude type of lateral balancing may be provided during fiight.

13. Means as in claim 12, characterized in that the selective means includes differential mechanism operatively connected to both in strumentalities and o erative in translating control movements'o the single control instrumentality into 'aerofoil movements.

14. Means as in claim 12 characterized in that the type of magnitude conditions is determined by the tamber control instrumentality,

15. Means as in claim 12 characterized in that the type of magnitude conditions is determined by the camber control instrumentality, with the latter-operative to produce the conditions of equal magnitude and a plurality of differing magnitudesto permit variation in the ratios of the relative movements of the aerofoils.

JOHN F. 0 OK, JR.

craft, and means operable by both control members to permit a selective change in camber ofthe aerofoils of the air-craft for lateral balance with theselection range including relative movement of the aerofoils of similar magnitude or movement thereof of differing magnitudes, the direction of major magnitude movement of the aerofoil in changing its camber to and from a nor-

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