US1793775A

US1793775A - Metal tipping for propellers

Info

Publication number: US1793775A
Application number: US368258A
Authority: US
Inventors: Charavay Frederick
Original assignee: HARTZELL INDUSTRIES
Current assignee: HARTZELL INDUSTRIES; HARTZELL INDUSTRIES Inc
Priority date: 1929-06-04
Filing date: 1929-06-04
Publication date: 1931-02-24
Anticipated expiration: 1948-02-24

Description

Feb. 24, .1931. F: CHARAVAY METAL TIPPlNG FOR PROPELLEHS Fig.6.

Filed June 4. '1929 Q 1 B! Q ATTORN/i) propellers.

Patented 24, 1931 UNITED STATES PATENT OFFICE FREDERICK CHARAVAY, OF IIQU'A, OHIO, ASSIGNOR OI ONE-HALF TO HARTZELL INDUSTRIES INC., OF PIQUA, OHIO, A. CORPORATION 01 OHIO METAL TIIPING FOR PROPELLEBS Application filed June .4,

This invention relates to new and useful improvements in metal tipping forairplane It is the principal object of my invention to provide a combination hard and soft metal tip for wood airplane propellers. A hard metal such as Monel, may be easily punched, but it is drilled with difiiculty. However, when the hard metal is used only on the face of the propeller, where it is most needed, and a soft metal such as brass is employed on the back side where there is little wear, the two metals may be easily riveted to the thin propeller tip by first punching the hard metal. The drill is then started through the latter, the propeller tip and the brass piece on its back side to provide holes to receive the rivets.

Such a propeller tip is armored with the hard metalon its face where it strikes weeds, stones and cinders, and with soft metal on its rear side where there is little wear. Furthermore, economy of manufacture is promoted by the use of soft metal with the hard, since the latter is more expensive, and when used on both sides of the tip increases the cost of its production.

It is another object of my invention to provide a soft metal strip, such as brass, along the leading edge of the rear portion of the wood propeller, with a serrated section of hard metal along that portion of the leading edge of the propeller where its velocity is high and where it is more exposed to the ele-' ments such as rain. 1

Other important and incidental objects will be brought out in the following specification and particularly set forth in the subjoined claims.

In the accompan ing drawings illustrating my invention, igure 1 is a view of the rear side of my improved propeller. Figure 2 is a cross sectional View takenthrough the .same on the line 22 of Figure 1, showing 1929. Serial no. 368,258.

propeller on the line 44 of Figure 1, show- 1ng' how the serrated hard metal strip is screwed over the middle front art of the leading edge of the propeller. igure 5 is a plan view of the hard metal strip attached to the propeller. And Figure 6 is a plan view of the soft metal piece attached to the propeller tip.

Referring to the accompanying drawings for a detailed description of my invention, the numeral 1 desi nates one end of a wood propeller of aerofoll section. The propeller is tipped with two metal strips, one of hard metal add the other of soft metal, to reduce the cost of production without impairing the efliciency 0 the propeller.

Referring to Figure 5, the numeral 2 designates a metal blank preferably of Monel metal, with a wide tapered head portion 3 and an elongated, serrated tail-portion 4. In Figure 6 there is shown a blank 5 of soft metal, preferably brass.

The brass strip 5 is first applied to the rear face of the pro eller tip and bent over its leading edge, a or which the Monel metal strip 2 is applied to the front face of said tip. The head portion 3 of the Monel metal strip 2 isthen lapped over the brass strip 5 and soldered to the latter as shown

ures

1, 2 and 3.

Holes are punched in the head portion 3 of the Monel metal strip'2 after which a drill is started through those holes, the thin propeller tip and the brass strip 5. Rivets 6 are then inserted in said holes and their heads soldered over. (See Figures 1, 2 and 3.)

Through the holes 7 1n the tail portion 4 of the Monel metal strip 2, screws 8 are inserted for passage into the propeller after said strip is bent over its leading edge.

Over the leading edge of the propeller 1, behind the Monel metal strip 2, a brass strip 9 is secured by screws. These screws, as well in Figas the. screws 8, are soldered over to make the surface of the brass and Monel metal strips uniformly smooth.

. The application of the Monel metal to the face of the propeller tip and to that portion of its leading edge immediately behind the tip reinforces it for the severe wear to which it is subjected through contact with stones, weeds and cinders and exposure to rain. The rear face of the tip, not being ex osed so much to the wearin action just re erred to, is covered with a so ter and cheaper metal such as brass which may also be easily drilled.

The tail portion 4 ofthe Monel strip 2, which is serrated to prevent buckling when the propeller vibrates, protects the leading edge of the latter at the points where its velocity is high. 7 Behind these, points, the leading edge is covered by the softer and cheaper strip 9. y

The propeller end (not shown(; on the other side of the hub is tipped an covered at its leadingedge in the same manner as the end which has just been described.

, Having described my invention, I claim:

- 1. A wood propeller of aerofoil section, having a combination hard metal and soft metal tip at each end.

2. A wood propeller of aerofoil section, having a combination hard metal and soft metal tip at each end, the hard metal being on the face side of the propeller, and lapping over the soft metal which is on the back side of said tip.

3. A propeller comprising a wood unit of aerofoil section, a brass strip applied to the back face of each tip of said propeller and bent over its leading edge, and a nickel and copper alloy strip applied to the front face of each tip, and lapped over the brass strip.

4. A propeller comprising a wood unit of aerofoil section, a soft metal strip applied to the back face of each tip of said propeller, a hard metal strip applied to the front face of each tip and lapped over the soft metal strip,

1 and rivets passing through the hard metal strip, propeller and soft metal strips for se- 8. In a propeller blade, a tipping therefor comprising a continuous strip of hard metal embracing a part of one edge and the face side of the ti of the blade, and a continuous strip of a so metal embracing another part of the same edge of the blade, one end of one strip' contacting an end of the other strip.

9. In a propeller blade, a protector therefor comprising a strip of nickel and copper alloy, and a strip of brass covering a leading edge of the blade, the strip of nickel and copper alloy covering that part of the blade most subject to wean 10. In a propeller blade, a protector therefor comprising a strip of nickel and copper alloy covering a leading edge and the face side of the tip of the blade.

11. In a propeller blade, a protector therefor comprising a strip of nickel and copper alloy covering a leading edge and the face side of the tip of the blade, and a brass strip covering the back side of the tip.

12. In a propeller blade, a protector therefor comprising a strip of brass covering the back side of the tip of the blade, and a strip of nickel and copper alloy covering a leading edge and the face side of the tip and overlapping the edges of the strip of brass.

In testimony whereof I have hereunto set my hand this 31st day of May, 1929.

FREDERICK CHARAVAY.

curing said metal strips to their respective propeller tips.

5. A propeller comprising a wood unit of aerofoil section a soft metal strip secured to the back face 0 its tip, a hard metal strip secured to the front face of said tip, and lapped 'over its leading edge, and having a serrated portionprojecting over the leading edge a short distance behind said tip, and a soft metal strip secured over the leading edge of said propeller behind the hard metal strip.

6. In a propeller blade, a tipping therefor comprising a continuous strip of metal embracing a part of one ed e of the blade, and a continuous strip of a di erent metal embracing another part of the same edge of the blade, one end of one strip contacting an end of the other strip.

7 In a propeller blade, a tipping-therefor comprising a continuous strip of hard metal embracing a part of one edgte of the blade, and

a continuous strip of a so ing another part of the same edge of the blade, one end of one strip contacting an end of the other strip.

er metal embracits