US2153610A - Rotative winged aircraft - Google Patents

Description

April 11, 1939- H. s. CAMPBELL 2,153,610

KOTATIVE WINGED AIRCRAFT Filed Nov. 13, 1955 5 Sheets-Sheet l INVENTOR BY WV MW ATTORNEY' April 11, 1939. H. s. CAMPBELL ROTATIVE WINGED AIRCRAFT Filed Nov. 15, 1935 3 Sheets-Sheet 2 ATTORNEY5 April 1939- H. s. CAMPBELL 2,153,610

ROTATIVE WINGED AI RGRAFT Filed NOV. 13, 1955 3 Sheets-Sheet 5' INVENTOR j ATTORN EYS Patented Apia-11, 1939 s PATENT OFFICE BOTATIVE WINGED AIRCRAFT Harris 8. Campbell, Willow Grove, Pa., assignor, by mesne assignments, to Autogiro Company of America, a corporation of Delaware Application November 13, 1935, Serial No. 49,451

11 Claims.

This invention relates to aircraft of the type having a sustaining rotor composed of a plurality of blades articulated to a hub mechanism, the rotor being actuable by relative airflow in flight. The invention is more particularly concerned with the mounting of the blades and control means for craft of this type, especially with that general type of control providing for shift of the lift line of the rotor with reference to the center of gravity of the machine so as to produce tilting moments. With the above in view, the present invention contemplates a mounting and control arrangement for a sustaining rotor in accordance with which the blades of the rotor are mounted for oscillative movements substantially about their longitudinal axes so as to vary the pitch, and in accordance with which control means are provided for producing a periodic change in the pitch of the blades during rotation of the rotor.

The invention has in view an improved mounting and control system of the type referred to, the same being not only of simple and rugged construction but also capable of compact arrangement.

More particularly, the invention contemplates the employment of articulations for the blades providing for swinging movements thereof in paths generally transverse the rotative path of travel, and also for pitch change movements thereof, the articulations for the latter purpose being located inboard of the articulations for the swinging movements. In this way, changes in pitch of the blades does not alter the angle of swinging thereof with respect to the chord line.

A further object of the invention is involved in the provision of a simplified control mechanism, this end being served by virtue of thearrangement of pivots just mentioned, it being pointed out that the control connections cooperate with blade parts located inboard of the pivots providing for swinging movements of the blades transverse their rotative path of travel, in consequence of which the control connections need not be made to accommodate or compensate for the said swinging movements of the blades.

How the foregoing objects and advantages are attained, together with others which will occur to those skilled in the art, will be more apparent from a consideration of the following description referring to the accompanying drawings, in which Figure 1 is a vertical longitudinal sectional view through a rotor head or hub mechanism constructed in accordance with this invention;

Figure 2 is a rear view of the structure of Fig.-

ure 1 with certain parts shown in elevation and others in vertical section;

Figure 3 is a top plan view of the mechanism shown in Figures 1 and 2;

.Figure 4 is a view similar to Figure 1 but show ing a modified arrangement; and

Figure 5 is a composite sectionalview taken substantially as indicated by the, section line 5-5 of Figure 4.

In the arrangement of Figures 1, 2 and 3, I 10 have illustrated a mechanism suitable for use with a sustaining rotor having an even number of blades, preferably four, the root ends of these blades being shown at 6. The blades and the hub structure therefor are preferably supported 15 above'the body of the craft as by means of a pair of forward pylon legs 1-1 and a centrally located rear pylon leg 8, the three legs forming a tripod joined, as by sleeves 9, to an apex box I 0. This box may conveniently be split horizontally as at 20 II for purposes of assembly and the like and is provided with sockets to receive the vertically spaced bearings l2 which serve to journal the tubular spindle I 3. A flanged and threaded collar H at the bottom of the spindle I3 serves to trans- 25 mit the thrust of sustension from the rotor to and through the lower bearing I2 from which it is carried through the apex casing ill to the pylon legs I and 8.

The spindle l3 projects above the upper bearing 30 I2 for the attachment of the blades thereto in the manner to be described hereinafter. Within the casing ID the spindle I3 preferably carries a sleeve l5 splined or otherwise secured thereto, this sleeve in turn serving to carry the drum l6 formed on its inner surface as a brake drum to cooperate with the brake parts H. An external ring gear I8 is also carried by the drum it, an over-running or free-wheeling device i 9 being interposed therebetween. A pinion 20 housed and journalled in an extension 2| of the casing I0 meshes with the ring gear l8 and serves to deliver torque to the rotor for starting or other purposes. The pinion 20 may, of course, be driven by shaft 22 extending downwardly between the two forward pylon legs I for connection with the engine provided for forward propulsion of the craft.

As best seen in Figure 3, toward its upper end the hollow spindle I3 is preferably squared to provide a number of flattened portions equivalent to the number of blades to be attached. Each side of the squared part is apertured and provided with a recess for a bearing 23. Opposed pairs of these bearings cooperate with each other inproviding a rotative mounting for a member traversing the hub and projecting from each side thereof for attachment of a pair of blades. One of these members, 24, is provided with a centrally apertured yoke 25, the aperture of which is somewhat larger in diameter than the transverse member 26 for the other pair of blades which passes therethrough, this latter member being journalled in the other pair of bearings 23. By virtue of the enlarged aperture in the eye 25, both of the members 24 and 26 may freely rock somewhat about the axes of their pairs of bearings 23-23.

For convenience in assembly and the like, each end of each of the members 24 and 26 is threaded as at 21 to receive a blade pivot part 28 which latter may also be pinned to the threaded part 21 as indicated at 29. Each pivot part 28 is apertured to receive the pivot pin 38 which serves to couple part 28 with a forked part or extension link 3|. The extension link in turn is connected by a pivot 32 with a forked fitting 33 at the root end of the blade 6. These pivots 30 and 32 provide freedom for force compensating movements of the blade in two planes, the first (30) permitting freedom for swinging of the blades generally transverse of their rotative path of travel and the second (32) permitting freedom for swinging movements fore and'aft in the general path of travel. The blades may be supported as against excessive downward droop about the pivots 36 by means of supporting cables 34 connected to the blades at a point spaced outwardly from the pivots and also connected with a cone or similar support 35 mounted at the top of the hub member I3.

For the purpose of controlling movement of the blades to vary' the pitch thereof, 1. e., movement about the axes of bearings 23-23, I employ a control member 36 having four prongs 31 projecting upwardly therefrom to embrace the members 24 and 26 at their point of intersection. These forks 31 engage fiatted portions or surfaces formed at opposite sides of each of the members 24 and 26 so that upon tilting of the control lever 36 one or the other or both pairs of blades are caused to change their pitch. The

upper ends of the forks 31 are preferably tied together by a member 38, studs 39 being provided for this purpose. The part 38 has its lower surface curved to fit and bear on the upper curved surface of the eye 25 in member 24.

The control arm 36 projects downwardly within the hollowed hub and preferably extends below the lower end of the hub, at which point it carries a non-rotating sleeve 40 within which the member 36 is free to rotate. Pairs of yokes 4| are pivoted to sleeve 40 as at 42 and each yoke serves for connection with a control cable 43. By virtue of this assembly the lever 36 may be tilted in any desired direction, the collar 40 and the associated yokes 4| remaining stationary while the control element itself (36) rotates with the rotor. The control cables may conveniently be carried downwardly toward the body of the craft, pulleys 44 for this purpose being mounted on the-pylon legs 1 and 8. As also seen by comparison of Figures 1 and 2, one of the control cables 43 is carried downwardly within the single rear pylon leg 8. cable is carried down between the two forward legs, a bracket 45 being provided for the guide pulley therefor. The two remaining cables,

which extend from the control element laterally toward opposite sides of the craft, are turned in a forward direction about the pulleys 46, after which these cables pass over pulleys 43 mounted The diametrically opposite.

on the two forward pylon legs 1-1 and extend therethrough toward the body of the craft.

From the foregoing it will be seen that by the structure of Figures 1 to 3 inclusive I have made possible the attainment of a number of advantages including the following:

The members 24 and 26 which interconnect opposed blades constituting pairs, serve to carry centrifugal loads directly from blade to blade across the rotor instead of through the hub itself. Still further, the arrangement while providing the foregoing, alsopermits location of all the blades of a four-bladed rotor in the same horizontal plane.

The control system is of especial advantage because of its arrangement and location, particularly with reference to the several-blade articulations. Note that the pivot for pitch change of the blades is disposed inboard not only of the horizontal pivots 30 but also of the drag pivots 32. In addition, note that the control lever 36 cooperates with the tie members between opposed pairs of blades within the hub itself. Such an arrangement not only simplifies the structure because of the compactness of effective utilization of space, but further for the reason that when connected in this manner the control system need not be designed to accommodate swinging movements of the blades either about the flapping pivots 30 or the drag pivots 32. Thus it is of advantage that the pitch change pivot be disposed inboard of other blade articulations, and further that the connection of the control lever with the blades be made centrally within the hollow hub.

A still further advantage of the construction described is that even though the number of bearings providing an axis for pitch change movements is equal only to the number of blades in the rotor, still a broad base is afforded by the pairs of these bearings.

In operation, the control cables 43 are, of course, actuated by a suitable mechanism within the body of the craft, such as the usual control lever, the hook-up of these cables being such as to provide for periodic pitch change of the blades in response to control member movements in the senses provided for in accordance with the copending application of Juan de la Cierva, Serial No. 698,372, filed November 16, 1933. As to the general nature and functioning of the control system, it may here be briefly stated that by movement of the control lever in the body of the craft in a forward direction and the consequent movement of the control element 36, the blades are caused to periodically change their incidence during the cycle of rotation in that sense which produces rearward displacement of the lift line with 'reference to the center of gravity of the craft.- This, of course, produces a nose-down moment and the control thus retains the instinctive control movements commonly adopted in aircraft practice. The case is similar with respect to transverse movements of the control stickin the body of the craft in lateral directions so as to produce banking moments and, in addition, for any combinations of control stick movements.

As a result of tilting the control element 36, of course (for example in a forward direction or to the left as viewed in Figure 1), the pitch of the blades in the fore and aft positions is not affected althoughthe pitch of the blades in the transversepositions' is changed. With a rotor turning counterclockwise when viewed in top plan, a forward movement of the control element 36 increases the pitch of the blade on the advancing side and decreases the pitch of the blade on the retreating side. Lateral and compound move ments of the control element 36 may also be traced out in a similar manner.

Turning now to the arrangement'shown in Figures 4 and 5, it is first pointed out that this structure is particularly adapted for use with a rotor having an odd number of blades, for example, a three-bladed rotor as shown. The three blades are indicated by the numerals 41. The hub member to which these blades are attached again takes the form of a tubular spindle, here designated by the numeral 48, this spindle being mounted in bearings 49 carried in a sleeve 50 which is supported by suitable struts or the like The upper portion 52 of the hub member 48 in this case is also formed with flatted portions, certain of which cooperate with the three blades. In contrast with the arrangement of Figures 1 to 3 inclusive, the three-bladed structure provides for individual attachment of the blades to the hub part 52. For each blade an attachment device 53 is arranged to project through an aperture in the hub part 52, this device having a threaded part 54 adapted to cooperate with member 55 which is journalled as by bushing 56 in the hub part 52 and projects outwardly therethrough to cooperate with the pivot 51 serving to couple member 55 with the forked blade root fitting 58. Each device 53 is provided with a shoulder or flange 59 for transmitting centrifugal loads of the blade to the hub part 52. Thus the blades are provided with articulations permitting freedom for swinging movement there of in paths generally transverse the mean rotative path of travel and, in addition, for movement substantially about their longitudinal axes to vary the pitch. With a view to supporting the blades when they are at rest or not rotating at flight speeds, I provide telescopic members 12 and 13 which interconnect the blades and a standard 14 at the top of the hub by means of pivots l5 and 16. A pin 11 secured to the inside member 12 and working in slot 18 in the outside member 13 serves to arrest downward movement of the blades on their flapping pivots 51. The member 12 is further mounted for rotation at 19 with respect to the end fitting 80 which is coupledito the blade, this freedom for movement being provided so as not to interfere with oscillation of the blades substantially about their longitudinal axes.

The member 53 for each blade is further provided with an inward projection 60 having flatted sides embraced by the fork parts Bl-6I of links 62 which depend therefrom for connection with the co trol element 63. At the upper end of each link 62 the fork parts 6| are preferably pinned as at 64 to the inner projection 60 of one of the blades. At their lower ends, the links 62 are similarly forked and the fork parts 65-65 embrace a joint block 66 which in turn is pivoted by a pin 81 to irs of apertured lugs 68 carried on the control Rlement 63.

As in he arrangement of Figures 1 to 3, the control element is preferably carried down to a level below the bottom of the hub member 48 and a ring 69 is mounted on the lower end thereof by a bearing I0. Control cables ll arranged in pairs at right angles to each other are attached to the ring 69 so as to provide for movement thereof in any desired direction.

The control members 60 to 68 inclusive, as described above, constitute a parallel linkage permitting freedom for swinging movement of the control elements 68 either fore or aft, or from side to side, or in other directions representing a compound movement. It will be noted that while a given horizontal plane in the control element 63 will rise somewhat during swinging thereof in any direction, still this plane will remain horizontal, and in operation movement of the control element G3 in one azimuth will not affect the pitch of the blades as they pass through that azimuth or through the azimuth diametrically opposite thereto, but will change the pitch of the blades as they pass through the two azimuths at right angles to the direction of movement. To further illustrate this operation, assume a movement of the control element 63 to the left as viewed in Figure 4. It will readily be seen that this movement will not affect the incidence of the forward blade 41 (at the left), but will change the inci dence of the two blades positioned 120 from the forward position. The degree to which the pitch of the blades is affected (upon a movement of the control element 63 to the left) will vary from a minimum in the fore and aft positions to a maximum in the two transverse positions. Assuming a rotor rotating counterclockwise when viewed in top plan, a forward displacement of the control element 63 effects an increase of the pitch of the blades as they are advancing and a decrease of the pitch as they are retreating.

By virtue of the arrangement of Figures 4 and 5, therefore, I have made possible the control of pitch of the blades of a three-bladed rotor in a manner to permit periodic pitch change throughout the cycle of rotation and thus shift of the lift v line with respect to the center of gravity of the craft for control purposes. In addition, numerous of the advantages mentioned above in connection with Figures 1 and 3 inclusive are also realized in the three-bladed arrangement, it being noted particularly that the structure is outstanding in compactness and simplicity, this latter purpose again being served by virtue of control connections which do not necessitate the use of any means for accommodating swinging movements of the blades about their flapping hinges 51. It will be understood that while I have not illustrated drag articulations for the blades in the arrangement of Figures 4 and 5, these may readily be adopted as in the construction of Figures 1 to 3.

I claim:

1. For an aircraft sustaining rotor having a plurality of blades, a hollowed hub member, a mechanism for connecting the blades with the hub member including pivot means providing for oscillation of the blades substantially about their longitudinal axes to vary the pitch thereof, and a control mechanism for periodically varying the pitch of the blades during rotation thereof, said control mechanism including a control element offset from the plane of attachment of the blades to the hub member, and parallel links in said hollowed hub member individually interconnecting the blades with the control element.

2. For an aircraft sustaining rotor having a plurality of blades and a hub member, a mechanism for connecting the blades with the hub member including pivot means providing for oscillation of the blades substantially about their longitudinal axes to vary the pitch thereof, and a control mechanism for differentially varying the pitch of the blades during rotation thereof, said control mechanism including a control element movable in a direction generally transverse the axis of the rotor, and parallel links interconnecting the control element and the blades, said links being pivoted to the blade for swinging movement in one direction and being universally jointed to the control element.

3. For an aircraft sustaining rotor having at least three blades, a centrally apertured hub member, pivot *means for connecting the blades to the hub member including, for each blade, a pivot providing for oscillation of the blade substantially about its longitudinal axis, the blades further having parts projecting into the aperture of said hub member, and control mechanism for periodically varying the pitch of the blades during rotation thereof including a control element offset from the plane of said parts, and links pivotally and individually interconnecting said parts with the control element.

4. For an aircraft sustaining rotor having at least three blades, a centrally apertured hub member, pivot means for connecting the blades to the hub member including, for each blade, a pivot providing for oscillation of the blade substantially about its longitudinal axis, the blades further having parts projecting into the aperture of said hub member, and control mechanism for periodically varying the pitch of the blades during rotation thereof including a control element movable in a direction generally transverse the axis of the rotor and offset from the plane of said parts, and links pivotally interconnecting the control element and said parts, each link being universally jointed to the control element and being connected with one of said parts for pivotal movement in at least one sense.

5. For an aircraft sustaining rotor having a plurality of blades and a hub member, a mechanism for connecting the blades with the hub member including pivot means providing for oscillation of the blades substantially about their longitudinal axes to vary the pitch thereof, and a control mechanism for periodically varying the pitch of the blades during rotation thereof, said control mechanism including a control element movable in a direction generally transverse the axis of the rotor, and parallel links interconnecting the control element and the blades, said links being pivoted to the blade for swinging movement in one direction and being universally jointed to the control element, the control element and links being rotatable with the rotor, a collar in which the control element is rotatively mounted, and actuating means cooperating with said collar to displace the control element.

6. For an aircraft sustaining rotor having at least four blades, pivot means interconnecting the blades in pairs, the pivot means of each pair providing for rotation of the blades substantially about their longitudinal axes to vary the pitch thereof, all of said pivot means being arranged to intersect substantially in a common horizontal plane and having flatted parts adjacent the point of intersection, and means for controllably varying the pitch of the blades including a control member having a plurality of fork elements engaging said flatted parts, whereby to effect oscillation of the blades in pairs substantially about their longitudinal axes.

7. For an aircraft sustaining rotor having a hub and a plurality of blades, pivot means interconnecting the blades, the pivot means of each pair providing for rotation of the blades substantially about their longitudinal axes to vary the pitch thereof, all of said pivot means being arranged to intersect substantially in a common horizontal plane, and means for controllably varying the pitch of the blades including a control member having a plurality of fork elements embracing the pivot means adjacent the point of intersection thereof, whereby to effect oscillation of the blades in pairs substantially about their longitudinal axes.

8. For an aircraft sustaining rotor having a plurality of blades, an apertured hub member, means for connecting the blades with the hub member including, for each blade, a mounting pivot positioned with its axis generally in alignment with the longitudinal axis of the blade, said pivot being journalled in the hub member and.

1 having a flatted portion projecting into the aperture of the hub member, and means for effecting a periodic change of pitch of the blades during rotation thereof'including a control member engaging the fiatted portions of the projections in said aperture.

9. For an aircraft sustaining rotor having at least four blades, pivot means interconnecting the blades in pairs, the pivot means of each pair providing for rotation of the blades substantially about their longitudinal axes to vary the pitch thereof, all of said pivot means being arranged to intersect substantially in a common horizontal plane and having flatted parts adjacent the point of intersection, and means for controllably varying the pitch of. the blades including I and into the interior thereof, the pivot member being journaled in the side wall of the hub for rotation about an axis generally in alignment with the longitudinal axis of the blade to pro vide freedom for pitch variation of the blade, and control mechanism for periodically varying the pitch of the blade during rotation of the rotor 1, including control means vertically offset from the plane of the blade and movable in any direction in a generally horizontal plane, and a substantially vertical link interconnecting said last means and the portion of the pivot device which projects into the hollowed hub, the con nection of said link and said pivot device providing freedom for relative angling of said two parts in a generally vertical plane containing the longitudinal axis of the blade but restraining relative movement of said two parts in a plane perpendicular to the longitudinal axis of the blade.

11. In a bladed aircraft sustaining rotor, a hollowed hub structure, means for mounting a blade on the hub including a pivot member projecting through a side wall of the hollowed hub and into the interior thereof, the pivot member being journaled in the side Wall of the hub for rotation about an axis generally in alignment with the longitudinal axis of the blade to provide freedom for pitch variation of the blade, and control mechanism for varying the pitch of the blade including control means vertically downwardly offset from the plane of the blade and its mounting pivot below the lower end of the hollowed hub, the control means being movable in any direction in a generally horizontal plane, and a substantially vertical link interconnecting said last means and the portion of the pivot device which projects into the hollowed hub, the connection of said link and said pivot device providing freedom for relative angling of said two parts in a generally vertical plane containing the longitudinal axis of the blade but restraining relative movement of said two parts in a plane perpendicular to the longitudinal axis of the blade. HARRIS S. CAMPBELL.

Images