US2780297A

US2780297A - Spinner construction

Info

Publication number: US2780297A
Application number: US415541A
Authority: US
Inventors: Barish Thomas
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1954-03-11
Filing date: 1954-03-11
Publication date: 1957-02-05
Anticipated expiration: 1974-02-05

Description

Feb. 5, 1957 T. BARISH 2,780,297

SPINNER CONSTRUCTION Filed March 11, 1954 INVE NTOR.

Thomas Barlsh m? K Mn/rk Hls Attorney United States Patent SPINNER CONSTRUCTION Thomas Barish, Cleveland, Ohio, assignor to General Motors Corporation, Detroit, Micln, a corporation of Delaware Application March 11, 1954, Serial N 0. 415,541

12 Claims. (Cl. 170159) This invention pertains to a spinner for an aircraft propeller, and particularly to a spinner construction wherein substantially no stress is imposed upon the propeller hub.

Heretofore, spinner shells for aircraft propellers have been supported on the propoller hub structure in such a manner that during rotation of the propeller, forces of substantial magnitude were imposed upon the hub by the spinner. Moreover, by the nature of the construction of prior spinners, rib supports of considerable weight and size were required to support the spinner from the propeller hub. This invention relates to an. intermediate annular spinner shell construction comprising a plurality of flexible sectors which impose virtually no bending stress upon their supporting ribs. Accordingly, among my objects are the provision of a spinner including a plurality of flexible sections, which are capable of deflection during rotation of the propeller; and the further provision of means for interconnecting flexible spinner sections so that the only stress imposed upon their supporting ribs is in tension.

The aforementioned and other objects are accomplished in the present invention by constructing a spinner shell of a plurality of flexible sections, and hingedly connecting the sections to a supporting rib structure. Specifically, the spinner construction of this invention is adapted to perfect the airfoil contour of a propeller having a hub with a plurality of circumferentially spaced, radially extending sockets. Each of the sockets is adapted to support the root portion of a propeller blade for rotation about its longitudinal axis. Each hub socket has attached thereto a spinner supporting rib structure, which essentially comprises a sheet metal member in the shape of a frustum of a pyramid. The base of the frustum is covered by an arcuate member having a cutout opening through which the propeller blade, carried by the hub socket, extends. The edge surfaces of the arcuate members are formed to constitute a hinge element, and each of the flexible spinner sections, or sectors, likewise, have their side surfaces formed as hinge elements. The spinner is assembled by inserting pintles through the interlocked openings of the hinge elements on the rib structure and the flexible sectors.

The spinner sectors are composed of relatively thin and flexible metal, normally having a substantially planar form, which is arranged to bulge outwardly during rotation of the propeller under the thrust of centrifugal force. The hinged interconnection between the supporting ribs and the flexible sectors is such that a pure tension stress is imposed upon the hinge, by reason of the fact that the flexible sectors are only subjected to hoop stress. In this manner, the spinner sections do not impose any bending forces on the ribs or on the propeller hub.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

2,780,297 Patented Feb. 5, 1957 In the drawing:

Fig. 1 is a fragmentary view, in elevation, of an aircraft propeller including a spinner constructed according to this invention.

Fig. 2 is a sectional view taken generally along the line 22 in Fig. 1.

Fig. 3 is a fragmentary view, in elevation, taken in the direction of arrow 3 in Fig. 2.

Fig. 4 is an enlarged sectional view taken along line 4-4 of Fig. 3. e

With particular reference'to Fig. 1, a propeller 10 is shown including a front spinner shell 11 of conventional construction, which is of a suitable aerodynamic shape substantially as shown. An intermediate spinner shell 12 is constructed according to the present invention, is sup I ported by the propeller hub, and spaced from the shell 11.

As shown in Fig. 2, the propeller 10 includes a hub 20 having four equally spaced, radially extending

sockets

21, 22, 23 and 24. Each hub socket is formed with a rim portion designated by the numerals 25 through 28. The rim portions 25 through 28 support a rib structure in the form of a frustum of a pyramid, the rib structures being designated by numerals 29 through 32. Each rib structure comprises four

sheet metal portions

33, 34, 35 and 36, which are joined along their edges and the assembly is rigidly attached to the rim portions of the'hub sockets.

The front and

rear portions

35 and 33 are formed with a curved, or arcuate, bottom surface to which a cover 37, having an arcuate configuration, is attached. Each cover 37 is formed with a cutout opening 38 through which blades 39 project. It is to be understood that the rib structures may be formed in two complementary'subassemblies so that they can be attached to the hub with the blades mounted in their sockets.

The blades 39 are preferably supported forrotati'on about their longitudinal axes in the hub sockets 21 through 24. Moreover, the propeller hub may embody suitable pitch changing mechanism of the type disclosed in the Blanchard, et al. Patents 2,307,101 and 2,307,102, for adjusting the pitch position of the propeller blades 39.

As shown in Fig. 3, the side edges of each cutout member 37 are formed with an interlocking edge portion 40 through which a pintle 41 may be inserted. Flexible spinner sectors 50 through 53, likewise, have their side edge portions formed with an interlocking edge portion 42, which is arranged to mate with the edge portion 40 of the rib structures, so that the pintles 41 may interconnect the sectors and the ribs, thereby forming a hinged connection therebetween.

As shown in Fig. 2, the flexible sectors 50 through 53, which are composed of thin metal sheets, are substantially planar when the propeller is stationary. However, upon rotation of the propeller 10, the flexible sectors 50 through 53 will bulge outwardly under the thrust of centrifugal force so as to form a substantially cylindrical surface in conjunction with the cover portions 37 of the supporting ribs. The bulging movement of the flexible sectors 50 from the chordal position indicated by full lines in Fig. 2 to the arcuate position indicated by dotted lines in Fig. 2 is permitted without permanent deformation of the sectors. As stated, the sectors 50 are composed of thin metal and, as is well known, within the elastic limit of metal, a metal member can be elongated under stress without permanent deformation if the elastic limit of the material is not exceeded. The position of tors and the ribs is that of pure tension. In other Words,

the flexible spinner sections are subjected only to a hoop stress, and if the hinge connection between the sectors and the ribs is such that the forces exerted by the flexible sectors under hoop stress act tangentially to the surface of the spinner, all bending forces normally imposed upon the hub by a spinner will be eliminated. In this manner, the necessity for high strength supporting ribs is removed, and since the hoop stress to which the flexible sectors is subjected does not vary with the thickness of the sectors, the sectors can be made of very thin metal, thereby resulting in a light spinner construction.

From the foregoing it is apparent that the present invention provides a spinner construction which eliminates the imposition of substantial forces on the'hub during rotation of the propeller. Moreover, the spinner construction of this invention lends itself readily to use with larger propellers wherein single and even two-piece spinner assemblies have become unwieldy.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A spinner construction for a rotatable propeller having a hub with a plurality of radially extending sockets and a plurality of blades retained in said sockets, including in combination, a rib structure attached to each hub socket, a cover portion connected to each rib structure having an opening through which the blade projects, said cover portion having an arcuate configuration, and a plurality of thin metal spinner sectors capable of elongation under stress within the elastic limit of the metal of which the sectors are composed, said sections having their ends operatively connected to said cover portions and arranged to elongate and bulge outwardly due to stress imposed thereon by the thrust of centrifugal force during rotation of the propeller to form a substantially cylindrical spinner periphery.

2. A spinner for a rotatable propeller having a hub, said spinner comprising a shell composed of a plurality of cutout members and a plurality of substantially planar thin metal sectors capable of elongation under stress within the elastic limit of the metal of which the sectors are composed, means interconnecting the sectors and the cutout members whereby said sectors are free to elongate and bulge outwardly due to stress imposed thereon by the thrust of centrifugal force during rotation of said propeller to form a substantially cylindrical spinner periphery, and means supporting said cutout members from said hub.

3. A spinner for a rotatable propeller having a hub, including in combination, supporting rib structure carried by said hub and including means constituting a portion of the spinner periphery, the remainder of said spinner periphery including thin metal sectors capable of elongation under stress within the elastic limit of the metal of which the sectors are composed, said sectors being interconnected with said rib structure and adapted to elongate and bulge outwardly during propeller rotation due to stress imposed thereon by the thrust of centrifugal force to form a substantially cylindrical spinner periphery.

4. A spinner for a rotatable propeller having a hub, said hub having a plurality of radially extending sockets, including, an arcuate cover section supported by each hub socket, a plurality of thin metal sectors capable of elongation under stress within the elastic limit of the metal of which the sectors are composed and arranged between hub sockets, and means interconnecting the sectors and the cover sections and arranged to permit elongation and outward bulging movement of said sectors during rotation of the propeller due to stress imposed thereon by the thrust of centrifugal force so as to form a substantially cylindrical surface with said arcuate cover sections.

5. The combination set forth in claim 4 wherein the means interconnecting the sectors and the cover sections comprise a plurality of hinges, and wherein a pure tension stress is exerted upon said cover sections by said spinner sectors during rotation of said propeller.

6. In an airplane propeller assembly, a hub having radially extending sockets, blades having their root portions extending into said sockets, and a spinner shell surrounding said hub comprising, a plurality of sections rigidly supported by said hub sockets and having cutouts through which said blades extend, and a plurality of thin metal sections, each thin metal section being capable of elongation under stress Within the elastic limit of the metal of Which each section is composed and having pivotal connection with two cutout sections between two hub sockets, said thin metal sections being constructed and arranged to elongate and bulge outwardly during rotation of said propeller due to stress imposed thereon by the thrust of centrifugal force so as to form a substantially cylindrical surface.

7. In an airplane propeller assembly, a hub having a plurality of radially extending sockets, blades having their root portions supported in said sockets, and a spinner shell surrounding said hub comprising a plurality of cutout sections equal in number to the number of said hub sockets and through which said blades extend, means for rigidly supporting said cutout sections on said hub sockets, and a thin metal section capable of elongation under stress within the elastic limit of the metal of which the section is composed and extending between each hub socket and operativcly connected to each cutout section, said thin metal sections being constructed to elongate during rotation of said propeller due to stress imposed thereon by the thrust of centrifugal force and impose a tension load upon the interconnection between tne thin metal sections and cutout sections by forming a substantially cylindrical spinner periphery.

8. In an airplane propeller assembly, a hub having a plurality of radially extending sockets, a plurality of propeller blades having their root portions supported in blade sockets, a spinner shell surrounding said hub including cutout sections through which said blades 07(- tend, and a plurality of thin metal sections capable of elongation under stress within the elastic limit of the metal of which the thin metal sections are composed, said thin metal sections extending between said cutout sec tions, means pivotally interconnecting said cutout sec tions and said thin metal sections, and means supporting said cutout sections on said hub, said cutout sections having an arcuate configuration and said thin metal sections being arranged to elongate and bulge outwardly during rotation of said propeller due to stress imposed thereon by the thrust of centrifugal force so as to form a substantially cylindrical spinner shell periphery.

9. The combination set forth in claim 8 wherein the means interconnecting the cutout sections and the thin metal sections comprise a hinge, and wherein said thin metal sections are subjected only to hoop stress during propeller rotation which imposes only a tension stress on said hinge connections.

10. The combination set forth in claim 8 wherein the means supporting said cutout sections on said hub comprise a plurality of ribs rigidly attached to the hub sockets and to the cutout sections.

11. A spinner for a rotatable propeller having a hub, said spinner comprising a shell composed of a plurality of rigid sections and a plurality of substantially planar thin metal sectors capable of elongation under stress within the elastic limit of the metal of which the sectors are composed, means interconnecting the thin metal sectors and the rigid sections whereby said sectors are free to elongate and bulge outwardly due to stress imposed thereon by the thrust of centrifugal force during propeller rotation to form a substantially cylindrical spinner periphery, and means supporting said rigid sections on said hub.

12. A spinner for a rotatable propeller having a hub, said spinner comprising a plurality of rigid sections operatively connected to said hub and a plurality of thin metal sectors capable of elongation under stress within the elastic limit of the metal of which said sectors are composed, said thin metal sectors being pivotally connected to said rigid sections and completing the spinner periphery, said thin metal sectors elongating under the stress imposed thereon by the thrust of centrifugal force during propeller rotation so as to bulge outwardly and form a substantially cylindrical spinner periphery.

2,329,606 Goodman Sept. 14, 1943 Junger Dec. 7, 1943 Harper Apr. 18, 1944 Marshall July 11, 1944 Marshall May 8, 1945 Rutledge June 21, 1949 Martin et a1 Aug. 29, 1950 FOREIGN PATENTS Great Britain Dec. 29, 1944