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Christian VOLF

Propeller








Popular Science Monthly

US Patent # 1,873,853



Popular Science Monthly
(Date unknown) 

"Spinner Plane Bids For Supremacy"

Revolutionary changes in aircraft may follow use of new type propeller that adds to speed and is silent

A design for a siren gave Christian A. Volf, Danish-borm acoustical engineer, an idea that may lead to such a new departure in aviation as the aerial leviathan on this page.

One day in his New York City laboratory, Volf was struck with the likeness between the spinning rotor that makes a siren's whine and an airplane's whirling propeller. The qualities that make a good siren, he observed, make a bad propeller for one reason alone --- noise. Aviation engineers would like to quiet the propellers of planes, for they make even more sound than the motor.

Many aviation experts have sought better propellers, but Volf started from an entirely new angle --- that of the acoustical expert. A "silent siren" could easily be built. Proceeding on this idea, he set out to design a noiseless airplane propeller. Instead of slashing at air, it would slip through it. The result of his work is a novel "spinner" or rotor rimmed with three-bladed scoops.

Volf set up his new propeller and a standard marine propeller in a tank of goldfish. The fish were struck and kiled by the revolving blades of the standard propeller. But they were sucked through the blades of Volf's propeller, following the natural course of the water, uninjured.

Whirling the new rotor in air confirmed that it was silent. But it showed a fact far more interesting. Its tractive force upon models was amazing, according to Volf. The combination of suction and pressure that it produced seemed to give an efficiency far surpassing that of standard propellers.

Out of this idea was born the revolutionary airplane that Volf now proposes. Enormous and silent, it would be driven by 8 of the odd spinners, or rotors, that Volf has invented, arranged in pairs. Each pair would have a vane above and below to direct the air through the blades. The whole assembly of rotors and vanes would be revolved at will by the pilot to tilt the ship up or down.

Theoretically, Volf declares, the spinners should be so much more efficient than ordinary propellers that they could support an airplane with practically no wing at all. He proposes first to build a wingless craft, and then add as much wing as turns out to be necessary for flight.


US Patent # 1,873,853

Rotor, Impeller, or the Like

Christian Volf

This invention is a rotor, impeller, propeller, or the like, which is capable of a variety of uses. The rotor comprises a plurality of blades of special design, one of the main features of which is that the fluid displaced by the rotor is discharged directly rearward substantially parallel to the axis of rotation. The rotor is capable of  broad application in pumping and displacing fluids, either gaseous or liquid. In other words, it is capable of use as a water pump, as an air pump, as a supercharger and in any other application where it is desired to displace a fluid.

The rotor comprises a plurality of blades, one of the chief features of which is a flange at the end of each blade extending substantially at right angles to the blade, this flange serving to prevent the escape of fluid from the blades in a radial direction, and serving to direct it straight to the rear. It is, of course, well understood, that the reactive force of a propeller is directly proportional  to the weight of fluid displaced rearwardly; fluid displaced tangentially or outwradly, has very little effect in creating a reactive push.

In fact, this propeller will direct the fluid leaving the blades not only directly rearwardly, but in a path which converges slightly toward the axis of rotation, which direction of flow tends to fill in the low pressure area caused by fluid flowing past the propeller hub and blades.

More specifically, each blade of the propeller comprises a back portion, which is substantially flat, the plane of which is substantially perpendicular to the axis of rotation. Merging with and connected to the back portion of the blade is an angled impeller portion, which is the promary agent in driving the fluid rearwardly. Bridging the space at the ends of the back and impeller portions, is a flange portion which is substantially perpendicular to the faces of the back and impeller portions. This flange is an important feature of the invention and is in the shape of a segment of a cylinder, the axis of which is coincident with the axis of the rotor.

The general features of the invention having been thus outlined, reference is now made to the accompanying drawings illustrating specific embodiments of the invention.

In these drawings,

Figure 1 is a view looking end on at the rotor, the rotor discharging toward the reader;

Figure 2 is a top view;

Figure 3 is a top view and section taken on the line 3-3 of Figure 1;

Figure 4 is a sectional view through a modification;

Figure 5 is a view of a detail of Figure 4; and

Figure 6 is a front view of Figure 4; and

Figure 7 is a view, partly broken away, of another embodiment.

Referrring now to these drawings, the rotor comprises a hub 2, from which radiate a plurality of blades oindicated generally at 4.Each blade comprises a back portion 6, which is substantially flat, and the plane of which is substantialy perpendicular to the axis 8-8 of the rotor. Secured to one edge of the back portion 6, along the line 10, is an angled impeller portion 12.

The rear edge of the impeller, represented by the line 10, is substantially perpendicular to the axis of the rotor. The delivery edge of the impeller portion, represented by line 13, extends inwardly at an angle, as shown in Figures 2 and 3, so as to converge with respect to edge 10.

Bridging across the space between the ends of back portion 6 and impeller portion 12 and attached to each of these portions along the lines 14 and 16 respectively is a flange 18, which is in the shape of a segment of a cylinder, the axis of which is coincidnet with the axis of rotation 8.  The curved flange 18 is preferably substantially perpendicular to the plane of the blade portions 6 and 12, that is to say, a tangent drawn to 18 at any point along the lines 14 or 16 would be substantially perpendicular to the plane of the blade portions 6 or 12.

As shown more particularly in Figure 2, teh flange 18, looked at from above, is substantially in the shape of a parallelogram with substantially equal sides.

Fitted on the hub 2 at the delivery side of the rotor is a conical cap 20 or the like for preventing eddying at this point.

When the rotor is rotated in the direction of the arrow at the right of Figure 2, fluid is driven as indicated by the arrows 22 substantially directly rearwardly although there is a definite tendency to drive the liquid or fluid along slightly converging lines, converging towareds the axis of rotation as indicated by the arrows 22. However, the blades can be designed to drive the fluid either directly rearwardly, or rearwardly on slightly converging lines, as desired.

Fluid enters between the blades through the spaces 24 at the intake side of the propeller.

The intake of one of these spaces 24 is substantially equal in area to the area of one of the back portions of a blade 6, which area is also approximately the same as the inside area of an impeller blade 12, and is also substantially equal to the outside area of one of the flange portions 18.

In operation, when the rotor is rotated, fluid enters between the blades at 24 and is driven directly rearwardly, or rearwardly on the slightly converging lines, by the cooperative action of the blade portions. This cooperative action may be expalined as follows. Fluid enters between the blades on the rotor and the angle at which they are placed, each of the rotors being the same, and their sum being 360 degrees. The angle of the impelling surface of the following blade counteracts this angle of the fluid and straightens it out. in the case of a 6-blade rotor, fluid enters at an angle of 30 degrees with the axis of rotation of the rotor and meets the impelling surface of the next blade, which is at a 30 degree angle and is going in the opposite direction from the fluid; the fluid is straightened out and driven in a line parallel with the axis. The flange 18 prevents any radial or lateral escape of fluid and directs it rearwardly or rearwardly and inwardly.

Referring now to Figure 4, each blade of the rotor has a back portion 6 and impeller portion 12 and a flange 18, as before. The corners between 6, 12 and 18 are preferably filled out and rounded out, as indicated at 26, so as to eliminate sharp corners and prevent the formation of eddies, thus promoting the smooth flow of fluid.

The delivery end of the hub 28 is provided with a cone 30 for preventing eddying on the delivery side. On the intake side the hub is provided with a concial extension 34 which serves to guide the fluid outwardly along its outer surface to the intake spaces 24 between the blades.

In order to facilitate the flow of liquid along member 34 and into the spaces 24 between the blades, spiral grooves 35 may be formed in the outside of member 34, the inner ends of the grooves opening into the space between the blades, at the roots thereof.

Figure 7 illustrates a modification where the back portion of the blade, here designated as 6', is reduced for a substantial part of its area so as to facilitate a more rapid flow of fluid to the impeller on the suction side. The area of this portion 6', reading outwardly from the root thereof, is substantially constant, not increasing appreciably until near its tip, where it is widest. The rest of the rotor is substantially like that shown in Figures 1 or 4 and corresponding parts are indicated by corresponding reference characters. This modification is particularly useful where there is not a great deal of back pressure to work against. If there is considerable back pressure, the form of invention shown in Figures 1 or 4 is more satisfactory.

It is of course within the contemplation of the invention to use two or more of any forms of the rotors in series. Where used in series they would preferably run in opposite directions.

While the invention has been illustrated in some detail, it should be understood that the invention is not to be limited to these details, but may be carried out in other ways as falling within the scope of the claims...

I claim: [ Claims not included here ]




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