US1905891A - Aeronautical propeller - Google Patents

Description

April 25, 3 w. J. BLANCHARD 1,905,891

Y AERONAUTKML PROPELLER Filed July 14, 19:50

(F161. FIGZ.

INVENTOR Patented Apr. 25, 1933 UNITED STATES PATENT OFFICE" WERNER J'. BLANGHARD, OF HEMPSTEAD, NEW YORK, ASSIGNOR '10 QURTISS AERO- PLANE Ga MOTOR COMIPANY, INC A CORPORATION OF NEW YORK AERONAUTICAL PROPEILER Applicationflled July 14,,1930. Serial No. 467,732.

My invention relates to aeronautical propellers and more particularly to one piece forged metal aeronautical propellers having thin solid blades and integral therewlth a central boss or hub forming enlargement.

The object of the invention is to so form and construct a one piece forged metal aeronautical propeller, as to secure unusual strength, minimum weight, uniformity of metal distribution, and decreased manufacturing cost.

Strength.--Maximum strength is obtained by reason of the fact that the tensile forces at or near the hub portion of the 1 propeller, instead of acting-at an angle to the longitudinal axis of the propeller blades,

acts in substantially a straight line and in parallelism with said axis. That this may,

be accomplished, the opposed blades, at or near said hub portion, instead of being formed in or twisted to out-of-alignment relation, lie in substantially the same plane and are of substantially uniform thickness and width even at their point of juncture with said hub forming enlargement.

Weight.The weight of the propeller is approximately twenty percent less than its contemporaries. Reduction is achieved by the economical distribution of metal at ornear the hub, as Well as by the complete elimination of that bulk of metal at or near the hub heretofore considered essential,

Uniformity of metal Through a more uniform and hence better distribution of the metal, a smoother running propeller is made possible and the imaging operation very materially simpli- Decreased manufacturing 00st.Production or manufacturing cost is lessened (a) by the elimination of metal bulk, (b) by a simplification of the forging operation and (0) by the elimination of the heretofore required and separately obtained twisting of the propeller blades. In the present invention, the propeller, instead of bein forged in the rough and thereafter twisted, is forged with the blades twisted or rather pitched to the required angle. Only the 50 finishing operation, i. e., filing and polish- -1010 and a central integral hub forming distributiowing,.is left undone by the forging operation.

By the substantial decrease in production cost made possible in the manner indicated, plus the elimination of metal bulk, it is now possible to manufacture and sell, at a reasonable profit, solid forged metal propellers, in competition with wooden propellers of similar size or dimension. Since it is an established fact that metal propellers having thin and solid blades are more efficient than the corresponding types of wooden propellers, obviously a step in the right direction in the advancement of the art of propeller manufacturing has been accomplished.

In the drawing, wherein like reference characters denote like or corresponding parts,

Fig. 1 is a face view of the propeller, and

Fig. 2 is an edge view or side elevation.

The propeller, as intimated, is of metal, preferably of an alloy of aluminum, such as duralumin, and is forged in one piece, and except for the filing and polishing, is completed in a single operation. As the twoblade propeller is by far the most common,

this particular type of propeller has been selected for illustration.

The propeller comprises opposed (blades 89 enlargement 11. The enlargement 11 is 5 formed by the provision of opposed bosses 1212 which extend out from the opposite faces of the blades 10-10 at the line of juncture of the blades, each boss or enlargement extending axially of the propeller and being of substantially uniform outside diameter and preferably substantially circular from end to end. In the interest of the elimination of metal bulk each boss or enlargement has an over-all diameter substantially less than the over-all width of the blades at their point of juncture. The enlargements 12l2, together with the mid portions of the blades 1010, form a hub of substantial length for accommodation on a. suitable propeller shaft. The hub thus formed is preferably at least twice as long as the longitudinal depth or thickness of the blades, to give an adequate mounting surface to assume torsional and rocking stresses to Which the propeller is subject.

The blades 1010, for some little distance at opposite sides of the axis of rotation of the propeller, are directly opposed, each making (see Fig. 2) a straight line continuation of the other. In other words, in the vicinity of the hub forming enlargement 11, the propeller blades are untwisted and of almost uniform thickness and width. Thus constructed, the weight is reduced and at the same tlme the strength increased. By

" making one blade a strai ht line continuation of the other in the vicinity of the hub, the forces. acting thru the hub (where the propeller is most heavily stressed) act in direct opposition and in .a manner such that better balance, a better distribution of metal bulk and substantially a twenty percent saving in weight is achieved. While it is apparent that in an aeronautical propeller the metalcannot be distributed in true uniformity, itis nevertheless felt that in the resent embodiment, such a condition has, 25

en more nearly approached than in any ropeller heretofore designed or constructed. oreover, by reason of the uniformdistribution of metal, the forging operat on is made easier and" a great deal more dependable, thus lessening the number of re'ections here'- tofore encountered in. the manu acture of on I all diameter not .portions of the and having a substantially uniform overreater than the width of the propeller bla es at the line of juncture therebetween. I 3. A one iece metal aeronautical propeller comprising a pair of integral op o- .sitely extending angularly' itched bla es, and a centrally disposed hu forming enlargement integral with said blades, the portions of the blades adjacent the hub being untwisted and each being a straight line continuation of the other.

4. A one piece metal aeronautical propeller comprising a pluralit of integral radially extending angularly itched blades, and a centrally disposed hub forming enlargement inte a1 with said blades, the

lades adjacent the hub being untwisted and lying in a common plane normal tothe axis of rotation of the propeller.

5. A one piece metal aeronautical propeller comprising a plurality of integral radially extendin angularly pitched blades, and a centrally isposed hu largement inte tions of the b ades adjacent the hub being untwisted and lying in a common plane normal to the axis of rotation of the proeller, said inner. blade portions being oined one -to another by continuations thereof enclosing said hub portion.

In testimony whereof I hereunto afiix my signature.

WERNER J. BLANCHARD.

lntegral therewith and on opposite faces thereof opposed hub forming enlargements,

said enlargements, in each instance, being of circular section and of substantially uniform diameter, the diameter, in each case, being substantially less than the width of the propeller at the line of 'uncture of the propeller blades, and the ength, in each case, being substantially greater than the 2. A one piece forged metal aeronautical I r0 ller comprisin thin solid 0 osed lad of substantiafily uniform thiizkness forming en.-. al with said blades, the por-

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