US2592118A - Deicing system for propellers - Google Patents

Description

April 8, 1952 c. w. cHlLLsoN ET AL DEICING SYSTEM Foa PRoPELLERs Filed Aug. 16, 1946 4 Sheets-Sheet l April 8, 1952 C. W. CHILLSON ET AL DEICING SYSTEM FOR PROPELLERS 4 Sheets-Sheet 2 Filed Aug. 16, 1946 April 8, 1952 c. w. cHlLLsoN ETAL.

DEICING SYSTEM FOR PROPELLERS 4 Sheets-Sheet 5 FiledAug. 16, 1946 April 8, 1952 c. w. cHlLLsoN ETAL 2,592,118

DEICING SYSTEM FOR PRoPELLERs Filed Aug. 1e, 194e zig, 7:

4 Sheets-Sheet 4 ATTORNEY Patented Apr. 8, 1952 DEICING SYSTEM FOR PROPELLERS Charles W. Chillson, Caldwell, and lXVard E. l Brigham, Jr., Packanack'Lake,`N. J., Aassignors to Curtiss-Wright Corporation, a immun-ation of Delaware Application Augustfl, 194B, Serial No. '691,125

This invention relates to aeronautical propellers and is concerned particularly with manifolding and ducting systems on controllable pitch propellers by which hot gas may be fed to the propeller during operation for preventing the formation of ice on the blades or for removing ice which may form on the blades.

It is known in the art that ice formation on propellers may be prevented by heating the propeller blades and various means have been proposed and used for this purpose, including the application of hot gas to the interior portions of hollow blades. Where hot gas is fed to the blades, it is ordinarily necessary to design special propellers so that the hot gas ducting may be in corporated in the basic propeller design, but we have found that a hot gas de-cing system can be applied to existing propellers.

It is an object of this invention to provide a hot gas manifolding system for a propeller by which a hot gaseous medium may be fed from a stationary part of the aircraft power plant to the interior cavities of hollow blades. A further object of the invention is to provide ducting and manifolding elements which can be applied to existing types of propellers Without extensive modification. Another object of the invention is to provide ducting and manifolding devices which may be applied to an existing type of propeller without major disassembly of the propeller. Still another object is to provide ducting and manifolding devices for a propeller which will be effective to confine the hot gaseous medium to its intended path without undue leakage, a related object being to provide sealing i means in the ducting and manifolding system which will permit limited relative motion between the propeller blades and their hub and between the propeller hub and the power plant to which it is attached While still retaining adequate sealing of the hot gaseous medium. In this connection, aircraft propellers operate under Vvarying stress conditions and it is inevitable lthat 2 Claims. (Cl. 244-434) vide a ducting and .manifolding system by which hot de-icing fluid may be transmitted both to the blades of a controllable pitch propeller and to the interior portions of cuffs which are secured to the propeller blades.

Further objects of the invention along with .a better appreciation of the scope thereof, will `become apparent in reading the annexed detailed description in connection with the drawings in which similar reference characters designate similar parts, and in which Fig. 1 is a longitudinal section through a propeller, hub and 'hub mounting incorporating features of the invention;

Fig. 2 is an enlarged fragmentary elevation. partly in section, showing details of the manifold structure;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Figs. 4, 5 and 6 are perspective elevations of parts oi' the blade manifold;

Fig. 7 is an renlarged fragmentary elevation, partly in section, of an alternative embodiment of the invention; and

Fig. 8 is a section on the line 8 8 of Fig. "7.

First referring to Figs. '1 through 6, an engine or power plant shaft I2 extends leftwardly from a stationary power plant housing I3, and a propeller hub I4 is secured in conventional fashion to the shaft I2. The propeller shown is of the electrically operated type wherein a series of slip rings I1 form part of the rear of the hub I4, said slip rings being engaged by brushes, not shown. by which electrical energy is fed to the propeller pitch change power unit. The power unit `is normally mounted on the front face of the hub Il but this assembly is not shown as it forms no part of the present invention. The particular details of the propeller are not important, asthe invention is applicable to any form of propeller. The hub I4 is provided with a plurality of integral blade sockets I5 within which blades I6 are secured. Only one socket and blade is shown as being typical of all sockets and blades. Blade securement is afforded by an internal nut I8 (Fig. 2) which, after being screwed into the socket I5, is secured from rotation by a keeper .2U screwedas at 2I to the nut I8, said keeper having atab 22 engaging one of several Vernier slots in the upper face of the blade socket.

The blade IG'is hollow and, as shown, vis provided with one or more ports 24 in its shank portion'so that a hot gaseous medium may flow into the hollow .of the blade for prevention of ice. Ordinarily, ythe blade I6 is provided witha vent "opening"near-ltstip.

34 and is secured thereto by screws 12.

We provide a stationary annular member 26 secured as at 21 to the power plant nose I3. The member 26 extends forwardly to embrace the slip rings I1 and then extends outwardly to form an annular disc parallel to the propeller plane of rotation and rearwardly of the propeller hub I4. This member, circular at its peripheryycarries a peripheral groove 28 to which is ttedva seal ring 30. The ring engages a cylindrical portion 32 forming the periphery of a disc 34 secured at 36 to a rearward portion of the propeller hub I4, said disc 34 being rotatable with the propeller. The member 26 carries a manifold 38 having an entrance flange 48 to which a duct leading from a source of hot gas is secured. Hot gas flows through the manifold 38 and then through` segmental openings 42 formed in the member 26. The disc 34 is provided with openings 44 lying opposite the openings 42 so that the hot gas in the manifold may ow with little loss of pres- -sure into the rotating propeller system. Loss of hot gas between the member 26 and the disc 34 is minimized by the seal ring 38 which permits relative rotation betweenthe member and disc and which further allows a limited amount `of axial and radial freedom so that the propeller hub may weave slightly with respect to the power plant nose without interfering with the effectiveness of the hot gas seal.

To the end of each blade socket nut I8 a ring 48 (Fig. 6) is secured by the screws 2I, said ring having tabs 50 through which the screws pass -and being split as shown for assembly, or not split, as desired. The exterior of the ring 48 is grooved as at 52 and a split ring 54 similar to a piston ring is inserted in this groove. Around the ring 48, a band 56 (Fig. 5) is wrapped, this band being split as at 58 and being provided with tabs 68 which may be drawn together by bolts 62 to close the band-and make it gas-tight. The band, for assembly, is spread and slipped over the propeller blade shank and is then clamped by the bolts 62 around the ring 54 and around an upper ring 64 Yforming a top closure for the band element. The lower ends of the band 56, adjacent the split 58, are provided with projections 66 -which engage beneath the ring 54 to hold the band assembly from outward displacement under the influence of centrifugal force. That portion of the band opposite the split'58 is provided with an opening 68 and a tting 18 vwhich lies against the inner face of the disc The rear of the band 56 is secured from outward displacement 'due to centrifugal force by its attachment to the disc 34 while the front of the band is secured from outward displacement by the projections 86 as described. The band is sealed with respect to the ring 48 (which may be split or solid) by the split ring 54 whole periphery engages the inner face of the band. The portion of the band adjacent the split 58 is provided with a tab 'I4 which overlaps the opposite band portion to provide a connection seal at the band' split when the band is secured by the bolts 62. v

*The outer rim of the band 56 is provided with a plurality of bent over tabs 16 which, during assembly, are inserted into a groove 18 formed in the outer edge of the two halves of the split ring 64. The split ring 64 is also provided with an interior groove 88 to receive a seal ring 82. 4The ring 82 ifdesired, may be made ofcarbonraceous material for heat resistance -and effective sealing and if so made, wpuldcompriseutwo halves. To secure these halves in sealing rela. tionshp to the shank of the blade I6. which they embrace. an interiorly tapered solid ring 84 is placed within the groove after which the ring elements 82 are inserted, the latter having tapered perpheries coacting with the tapers of the ring 84, the Whole being assembled around the blade shank with the closure 64 after which the band 56 is assembled with the tabs 16 in the groove 18. With propeller rotation, the ring 84 is urged outwardly by centrifugal force, wedging, by virtue of the tapers, the ring halves 82 into firm sealing engagement with the blade Shanks.

With the assembly of the band 56, the ring 48, the closure ring 64, the related seals, and the disc 34, it will be seen that a chamber or manifold 8,6, gas-tight in character, is formed around the propeller blade shank so that hot gas admitted from the manifold 38 through the openings 42, 44 and 18 will pass around the blade shank and into the blade hollow through the blade shank opening 24. Most of this assembly may be applied to the blade shank without removing the blade I6 from the socket I5 and no major modication of any of the normal propeller components is required. The manifold assembly around the blade shank can be readily removed for servicing of either the gas ducting system or of the propeller itself.

The disc 34 may, if desired, form a rearward spoke element to support a propeller spinner 9U which is secured at its rearward end by bolts 92 to a suitable flange 94 formed integral with the disc 34. The spinner extends around and forwardly of the propeller hub, openings 96 being formed vin the spinner for the propeller blades, and a part of the spinner forward of the propeller may be given further support by a spoke or diaphragm member 88 secured at its outer periphery to the spinner and at its inner periphery to a spinner support |80 secured as at I02 to the propeller hub I4.

In the operation of the propeller with the gas manifolding system installed, the blade I6 may weave within its socket I5 whereupon the seal ring 82 will move freely in a radial direction within -its groove 80 in the member 84. The blade is free for pitch changing rotation in the socket by rotation of the ring 82 in its groove or of the blade relative to the ring. Sealing effectiveness is maintained during propeller operation by the combined action of the ring 84 on the seal ring 82 and by the tendency for centrifugal force to force the outer surface of the ring 82, against the surface of the groove 80. The closure 64 is constrained against displacement by centrifugal force by engagement of the tabs 16 with the member t4.V The band 56 is constrained against displacement due to centrifugal force by the securement to the disc 34 and by the engagement of the tabs 86 with the ring 54 which in turn is constrained against displacement by the securement of the ring 48 to the propeller hub assembly.

Reference may now be made to Figs. '7 and 8 wherein an alternative arrangement of the inven- -tion is shown. The annular member 26 with its hot gas manifold 38 and its peripheral seal ring 3D issubstantially the same as in the previously described embodiment. The disc 34 is also similar to that already described except for certain modications concerned with its attachment to the blade embracing manifold, which comprises a chamber forming means. Y

.The blade embracing, manifold or chamber forming means comprises a band |06 embracing the shank of the blade I6, the lower edge of the band being secured by screws |08 to a sleeve ||0 which is fitted around the outer end of the blade socket I5. The sleeve |I is provided with an outer flange 2 resting against the outer face of the blade socket to limit its inward movement. The bottom end of the sleeve IIlly is provided with a plurality of slits ||4 defining tabs ||6 which are bent inwardly to engage an inwardly tapered surface |5a of the socket I5. The tabs ||6 are bent outwardly to form flanges as at I I8. A clamp band |20, secured by a bolt |22, is wrapped around the tabs IIB, resting at its lower edge against the flanges ||8, thus securing the tabs ||6 firmly to the bladesocket and securing the manifold band |06 in position upon the blade socket.

The band |06 is provided at the rearward portion of the propeller, with an opening |24 em bracing a ferrule |26 secured to and passing through an opening in the disc 34. This ferrule provides an entry for hot gases from the manifold 38 to the zone surrounding the blade shank, outboard of the hub socket. The blade shank is provided with a gas entrance opening 24 for passage of gas into the hollow interior of the propeller blade I6.

The propeller blade shank is equipped with a vented streamlined cuff |30, secured to the blade through a split forging |32 which embraces the blade shank, said split forging being anchored in position by bolts |34. Since the interior of the cuff |30 is hollow, and since the exterior of the cuff is subject to ice accretion in the same fashion as the blade is so subject, it is desirable in a cuifed propeller to make provisions for warming it. Accordingly, we provide a segmental duct |36 which extends from the chamber |38 formed by the band |06 outwardly through the forging |32 so that hot gas may flow from the blade chamber into the cuif hollow. This duct |36 is secured to an inner portion of the forging |32, the latter providing a partial closure for the outer end of the blade embracing chamber. forging |32 which embraces and contacts the blade |6 is shown at |40, said portion having a groove fitted to an annular rib |42 formed on the blade shank I6. This rib constrains the cuff assembly from outward displacement due to the action of centrifugal force.

A clamp ring |44 embraces the forging portion |40 and carries a fiat ring |46 forming the remainder of the outer closure for the chamber |38. Said flat ring forms a sealing abutment for a piston ring seal |50 which bears at its periphery on a wear surface |52 integral with the band |06, the outer side face of the ring seal |50 bearing The portion of the upon the inner face of the flat ring |46 under the influence of 'centrifugal force. This provides a sealing closure for the chamber |38 and permits relative weaving between the propeller blade and its socket along with rotational freedom of the blade in its socket for pitch change. The major portion of the band assembly of which the band |06 forms a part of rigidly secured to the propeller hub, while the outer closure portion is rigidly secured to the propeller blade shank. It will be noted that the duct |36 feeding hot gas to the cuif |30 is also rigidly secured to the propeller blade so that it may move therewith and with respect to the propeller hub.

While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications and changes.

What is claimed is:

l. As an article of manufacture for use on a propeller including a socket and a blade rotatably secured therein said blade having a port outboard of the blade socket; a split ring for assembly around the blade shank and secured to the outer end of the socket, an open ended flexible band embracing said ring and embracing the blade shank in spaced relation including means to engage said ring and means to clamp the band tightly aro-und the ring, said band including an opening for communication with a hot gas supply, another split ring secured adjacent the edge of and to said band at the edge thereof remote from said socket, and means for sealing the relatively 'rotatable blade shank and outer split ring to one another, said rings, band and sealing means being mountable on said propeller with the blade installed in its socket.

2. As an article for use in a controllable pitch propeller including a rotatable hub having blade sockets extending therefrom and having a blade mounted for pitch change in each socket, each blade having an aperture in its wall` outboard of said socket; an annular band surrounding each blade, secured in sealed relation to the outer end of its socket, and defining between the blade and band an annular chamber communicating with the blade aperture, a closure for the outer end of said annular chamber having a portion secured to the outer edge of the band and a portion sealingly engaging the blade shank, said portions REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,899,689 Houston Feb. 28, 1933 2,503,451 Palmatier Apr. 11, 1950

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