US2272358A - Airplane propeller - Google Patents

Description

Feb. 10, 1942. E. c. STEINHAUS AIRPLANE PROPELLER Filed Dec. 2, 1940 Edward 6; Stel'lzham:

INVENTOR BY amyamwza.

ATTORNEYS WITNESS Patented Feb. 10, 1942 Application December 2, 1940, Serial No. 368,241

g 4 Claims. ('01. 170-172) This invention relates to airplane propellers and more particularly to those which are hollow and utilize a flow of compressed air'through ducts on the surface thereof.

In the conventional type of propeller, the high rate of speed at which the blade rotates tends to'create a vacuum or partial vacuum on its forward or low-pressure surface and the effect of this vacuum is to exert a retarding force on the rotationof the propeller.

r Various means, such 'as ridges, fins, etc. have been utilized to break up this vacuum but, so far as I am aware,

no one has as yet developed a device which makes use of a stream of compressed air which not only abolishes this vacuum but will assist the motor of the propeller as will the specific advantageous combination of elements embodied in my invention.

Said shaft is hollow, and has ducts positioned so that air may be forced bya compressor, not shown, therethrough and into the hollowblades Ill.

Positioned on the forward, or low-pressure surface of the blades are convexities l6, shaped in a backwardly tapering form similar to the back The object of this invention is to decrease the air resistance in airplane propellers.

Another object is to abolish the vacuum, which forms on the low-pressure surface of airplane propellers.

Still another object is a means of assisting the rotation of airplane propellers.

These and other objects may be accomplished by my invention which embodies among its features a propeller having hollow blades, a hollow shaft for said propeller having air ducts leading to' the interior of said blades, a plurality of convexities arranged on the forward or low-pressure surface of each blade,said congexities having a tapering shape to decrease air resistance, an air outlet positioner directly in front of each convexity and consisting of astamped-up portion of the surface of the blade, semi-circular in crosssection and directed toward the convexity so that,

when air is forced therethrough, it will overcome any vacuum and also will produce a force to augment the drive of the propeller.

Other objects and features will become evident from the following disclosure when taken in connection with the accompanying drawing in which: a

Figure l is a front elevation of a hollow propeller blade including my invention,

Figure 2 is a cross-section taken on line 2-2 of Figural, and

figure 3 is a cross-section taken on line 3-3 of Figure 2.

' Referring to the drawing in detail, my propeller consists of two hollow blades l0, each held in a socketiiby clamps' l2. ihe socket II is made integral with hub l3 which is securely fixed in conventional manner on under forced pressure therein, a plurality of con--.

of a spoon or a' drop of oil falling through air to thus minimize air resistance. The spaces be-' tween thes'e'convexities may, if desired, be slightly concave, and the convexities are positioned so that their surfaces taper. down to the trailing edge of the blade. Directly in front of the convexlties are air outlets l1 stamped out of the blade, the same being semi-circular in crosssection, as shown, and positioned to direct jets of air back over the convexities. when air is forced through the shaft l4 into the hollow blades, these backwardly directed jets not only obviate the formation of a vacuum on the-lowpressure side of the blade, but exert a considerable force to cause the .blades to rotate;

Therefore, it will be noted that I have produced a blade which can be rotated at a greater rate of speed with the expenditure ofv less horsepower and in general has greater efficiency than the blades now in use. Although a preferred embodiment is described herein I do not wish to appended claims:

What I claim is:

1. In a device of the class described, a hollow propeller blade open at one end to receive air vexities formed transversely on the low-pressure side of the said blade, the said blade having air outlet openings forwardly of the said convexities, and means projecting from the blade for directing the air escaping from the said openings toward the said convexitles.

2. In a propeller, a hollow blade open at one end for the admission of air under forced pressure, a plurality of convex protuberances formed drive shaft H. 5

on the blade, ,the said protuberances being tapered longitudinally and arranged transversely of the blade, the said blade having outlet aper-' tures adjacent the ends of the said protuberances, and projections formed on the blade partially covering the said outlet apertures and shaped to direct the air blowing outward of the apertures on to the said protuberances.

3. In a propeller. a hollow elongated blade open at its inner end for connection with a passage for supplying fluid under pressure into the bladr' a plurality of transversely disposed protuberances formed on one side of the blade, the

' said protuberances being tapered and having one end terminating at the trailing edge of the blade, the said blade having fluid discharge apertures in one side thereof immediately'forward of the discharge apertures adiacent one end of each of the protuberances, a semi-circular deflecting member formed about a portion of each aperture to direct the fluid escaping therefrom toward the protuherances, a hollow shaft having a plurality of side outlet ducts, and a plurality of radial socketsmounted on the shaft for connecting the blade to the shaft so that the inner open ends of the blade register with the ducts whereby fluid may be forced through the shaft and into the blades, and discharged through the apertures in the blades. 7

EDWARD C. STEINHAUS.

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