US2231772A

US2231772A - Method of making a hollow propeller blade

Info

Publication number: US2231772A
Application number: US194330A
Authority: US
Inventors: John H Nelson
Original assignee: Wyman Gordon Co
Current assignee: Wyman Gordon Co
Priority date: 1938-03-07
Filing date: 1938-03-07
Publication date: 1941-02-11
Anticipated expiration: 1958-02-11

Description

Feb 31, 1941. J. H. NELSON METHOD OF MAKING A HOLLOW PROPELLER BLADE Filed March 7, 1938 2 Sheets-Sheet l Feb. 11, 1941. J. H. NELSON METHOD OF MAKING A HOLLOW PROP-ELDER BLADE Filed March '7, 1938 2 Sheets-Sheet 2' c 51 um 50 positions shown Patented Feb. 11, 1941 mz'rnon or MAKING A nonLow morerun nuns 1.1... a. ram, Holden, m. designer to Wyman-Gordon- Company,

corporation of Worcester, Mass; a usetts Application smell 1, issaseriai No. 194,330 J 1 @laim. (c1. es-ms) This invention relates to propeller blades for aircraft enginesand particularly to hollow blades made of steelor other metal or alloy of high tensile strength and adapted to be forged and welded or brazed. In the following specification and claim, the term steel" is to be understood to'be descriptive only and to include ferrous alloys and all other metals or alloys which meetthe requirements above set forth.

provide a hollow steel propeller blade of novel construction, and to provide an improved method of manufacturing such a blade. 7

. More specifically, 1 provide a hollow steel blade 1 comprising two forged casing portions and a single longitudinal reenforcing rib or stiffening member. all three parts being permanently secured together by welding or brazing operations.

My invention further relates to certain arrange- 20 merits and combinations of parts and to certain ordered procedure which will be hereinafter described and more particularly pointed out in the appended claim.

A preferred form of the invention is shown in 2!! the drawings, in which Fig. l is a plan view of my improved propeller blade? Fig. 2 is a plan view, partially broken away, and showing forged blanks from which the two 30 casing portions of my improved blade are formed; Figs. 3 and 4 are transverse sectional views, taken along the lines 3-! and 4-4 in Fig. 2 respectively;

Fi'gs. Sand 6 are sectional views corresponding 35 to Figs. 3 and 4 but showing the blanks forged or pressed to finished shape;

Fig. 7 is aperspective view of a portion of the longitudinal stiffening rib; Figs. 8 and 9 are transverse sectional views of 40 the finished propellentaken along the lines 0-! and 9-9 in Fig. 1 respectively; and 1 V Fig. 10 is an enlarged detail sectional view to be described. h h Referring to Figs. 1, 8 and 9, I have shown a propeller blade B of hollow cross section and 4 comprising casing portions 2'. and 2| and a longittudinal stiffening rib 22, all permanently secured together by welding or'brazing in the relative in Figs. 8 and 9. The propeller blade B is also provided with the usual hollow circular hub portion 24 by which it is attached to the driving shaft of a suitable engine. i gs The blank 2| from which the casing portion It is the general object of my invention to be' joined together is formed-is shown in cross section in Fig. 3 and comprises two. flat and relatively thin side portions 2| and 2'8 and a relatively heavy upset rib 21 located opposite a depressed portion or groove 28.

It will be understood that the portions 25 and 5 26 vary in width in different parts of the blank, so as to provide the required stock to form a blade of the varying cross section indicated in Figs. 1,

, 8 and 9. v I

The blank 2 I shown in Figs. 2 and 4 is similarly provided with flat portions and 36 separated by a relatively heavy upset rib 21 located opposite a depressed portion or groove 38.

After the blanks are formed as described by forging or press operations, the blanks are pressed and folded as indicated by the arrows in Figs. 3 and 4 to the U-shaped sections shown in Figs. 5 and 6. This operation is preferably performed by dies in such manner that the surfaces will be brought to the exact contours required in the finished blade.

The longitudinal strengthening rib 22 is then placed between the edges of the portions 20 and 2| of the blade and the parts are permanently secured together by welding or brazing operations.

In order that all parts may be firmly held from displacement during said welding or brazing operation, the edges of the rib 22 are preferably recessed as indicated at 40 in Fig. 10 to receive the edges of the forged casing portions 2|) and 2|, which edges have'previously been machined to the exact required outlines.

During the pressing and folding operation the hub portions 42 and 42 (Fig. 2) of the blanks may be bent to semicircular form and these parts may to form the complete hub2l when the other parts of the blade are welded or brazed.

Having thus described my improved'propeller bladeand my improved method of making the same, it will be seen that I have produced a hollow steel propeller blade comprising two forged casing portions strong y reenforced at the edges of the blade, and a single additional longitudinal stiffening member to which the forged portions are permanently welded or brazed.

, Such a propeller blade has the desired light weight associated with the necessary high tensile strength, and is adapted to resist the severe stresses-to which it is subject in operation.

The blade may be twisted to provide the necessaryhelical pitch at any convenient point inthe operations d Preferably the blade is twisted after the parts are assembled as shown in Figs. 8 and 9 but before the welding operation, ll

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claim but what I claim is:

The method of making a hollow metal propeller blade having curved front and rear outer edges and which tapers gradually in width from an intermediate point toward the outer end and abruptly in width from said intermediate point toward the inner end; which method comprises forming a pair of substantially fiat forged blanks each having one straight edge and one curved edge and each being widest intermediate its ends and tapering toward the ends; forming in each blank-an integral longitudinal rib of substantially greater thickness than the flat portion of the blank and near the center 01 the blank which rib is in part longitudinally curved and follows a line approximately midway between the variably spaced edges of said blank throughout the major portion of the length of said blank; bending each blank about its longitudinal rib thereby forming therefrom complementary casing portions of substantially U-shaped cross section and tapering toward each end; assembling said U-shaped casing portions with the rib portions outermost and theinner edges engaging a longitudinal metal stiflening member; and permanently securing the easing sections and said stiffening member by welding the parts together along the lines of 'junct e, thereby forming a complete propeller blade, wherein the curved oflset ribs constitute integral reinforced curved edges for the blade.

JOHN H. NELSON.