US2106928A - Air or water craft propulsion - Google Patents

Description

Feb. 1, 1938. c. M. LEE

AIR OR WATER CRAFT PROPULSION I Filed June 50, 1957 Patented Feb. 1, 1938 UNITED STATES PATENT OFFICE Application June 30',

4 Claims.

The propeller construction herein disclosed is made for the purpose of driving air or water craft by means of static pressure of the sustaining medium in back of the craft. It thus, with airplanes, has the function of removing air from in advance of the driven object rather than driving the craft by a screw action through the air, which latter is the common practice of this day. In water it does not waste work in the manner of screw propulsion by building bow waves through sheer pressure.

A purpose of the invention is to decisively increase the speed of air craft or water craft over that which may be had by screw propulsion methods now in general use. A further purpose of the invention is to provide a propeller blade arrangement whereby the differences in pressures on opposite sides of rotating blades counteract centrifugal force and enable the use of a lighter 20. construction relative to the work performed than may be had by radial blades. In this case the blades are longitudinal or extend in the direction of flight, have a double curvature, and afford a highly streamlined propulsion means. With reference to this double curvature a further object of the invention is to strengthen the structure to resist centrifugal force and to give the blades a long leading edge and a large area with reference to the over all dimensions.

Another object of the invention is to provide a blunt nosed air craft giving a substantial effective area, athwart the direction of travel, with means for removing air from in advance of the blunt surface; thus making use of the static pres- 35 sure of air on other parts of the craft for driving it forward.

The purposes of the invention are accomplished by means of a construction diagrammed in the drawing to accentuate its principles without undue use of variable details.

In the drawing, Fig. 1 is a plan View of the propeller and its mounting and includes a fragment of a plane with the motor location in the fuselage indicated.

Fig. 2 is a perspective view of the propeller removed from its bearings.

Fig. 3 is a sectional view as indicated by the line: 3-3 on Fig. 1.

Fig. 4 is a fragmentary view of a modified end construction for the propeller.

This propeller construction is in the general form of a cylinder, except that the blades are given about a ten degree pitch with reference to tangents of the encompassing curve. The structure has an open front and a closed rear end 1937, Serial No. 151,189

and operates to draw air inwardly through the open front end and to drive the air outwardly through the spaces between the blades leaving a. Partial vacuum in advance of the closed end of the cylinder. This closed end forms a blunt nose for the bow of the craft and is shielded against inflow of air by a cylindrical reinforcing flange at its periphery. The blades preferably do not extend parallel with the axis of the cylinder in one sense, but have helical curves which add to the resistance of the structure against centrifugal force; increase the area of the blades, and increase the length of the effective air entering edge of the blades.

The propeller rotates in the direction indicated by the arrow in Fig. 2, and the outer face of each blade I 5 is the working face and the for- Ward edges of the blades are nearer the axis of rotation than the trailing edges for the purpose of throwing the liquid outward and rearward, and in this manner bring about the reaction that drives the craft forwardly.

The pitch of the blades with reference to the general cylindrical form is varied according to a predetermined diameter and its average rate of rotation, but for maximum efficiency in high speed work the pitch is in the neighborhood of ten or eleven degrees to avoid any approach to destructive vibration at high speeds. Proportions are varied according to the work performed, and load, with reference to maximum dimensions.

In the example illustrated the cylinder length is approximately three times its diameter. Many variants in construction or proportions are possible without departing from the main purposes or principles of the invention. Ordinarily with the use of screw propellers an increase in thrust of the propeller may be desired to increase the speed of the plane when overloaded and this is accomplished by pitch changing or by substituting a propeller of greater pitch. With the present suction producing propulsion means a greater thrust may be attained for the purposes of increasing speed by substituting a propeller of larger diameter and greater length without change in pitch.

The drawing indicates a rigid frame structure I providing bearings 2 and 3 for the propeller. The propeller shaft 4 is coupled with the crank shaft of a radial engine indicated by the dotted outline 5. 6 represents the fuselage of a plane and l the supporting wings thereof. The propeller construction rigid on shaft 4 includes the hubs 8, 9, and II) respectively connected with the cylindrical air evacuating means by spokes l l and I2, and a disc web I3. Spokes II at their outer ends are attached to an open ring M. The outer ends of spokes I2 are secured to the central part of the blades I 5 extending from ring M to a peripheral flange IS on web I 3.

Web 13 is shown extending at right angles to the axis of shaft 4 to afford a decisive illustration of an effective area in advance of which air is removed to cause the propulsion of the craft. In some cases this web is of conical form as indicated at I! in Fig. 4, thatis, insteadof extending from hub ID to the ring-shaped iiange l6, it forms a continuation of that flange and extends to the hub 9. Such cone form is illustrated because it has been used effectively and ispreferred in cases where the propeller is sometimes stationary while the craft is in flight, or in the case of sailing vessels equipped with an auxiliary.

In the operation of the propulsion means the effect of the rotating longitudinal blades is to throw the air'or water, through which the craft is traveling outwardly from'within the hollow cylindrical propeller. The blades also produce a rearward thrust on the air or water, because of their helical arrangement. The rear end of the propeller is closed or that space is otherwise blanked off'by the body of the craft when the propeller is mounted at the back end thereof. Due to the vacuum conditions produced within the cylinder, the air or water attains velocity in the direction of the axis of the cylinder, but is thrown outward, the result being a rearward flow outside of the periphery of the propeller in the general direction which would be caused by the operation of a screw propeller. Hence this flow of the air, in the case of an air craft, aids in producing a lift at the supporting surfaces supplemental to the lift caused by the forward movement of the plane through the air.

This method of propulsion provides a vacuum tube system operation in the open. With it the around the cylinder.

2. A propeller of the class described of general hollow cylindrical form and including end supports connected by pitched helical peripheral blades having their working faces on the outside and with their forward edges nearer theaxis of rotation than the rear edges, and closing means for one end of the propeller extending from the axis to the periphery of the cylinder.

3.-A propeller of the class described of general hollow cylindrical form and including end supports connected by pitched helical peripheral blades having their working faces on the outside and with their forward edges nearer the axis of rotation than the rear edges, a conical closing end means for one end of the propeller extending from the axis to the periphery of the cylinder.

4. A propeller of the class described of general hollow cylindrical form and including end supports connected by pitched helical peripheral blades having their working faces on the outside and with their forward edges nearer the axis of rotation than the rear edges, a closing end means for one end of the propeller extending from the axis to the periphery of the cylinder, and a peripheral flange or guard associated with said end closing means for preventing inward flow of air at that end of the propeller.

CHARLES M. LEE.

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