Propelling device

Feb. 15, 1938.

H. COANDA

PROPELLING DEVICE

2,108,652

Filed Jan. 10, 1936

Sheets-Sheet 1

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INVENTORHENRI COANDA

ATTORNEYS

FeKIS, 1938.

H. coanda 2,108,652

PROPELLING DEVICE

Filed Jan. 10, 1936 2 Sheets-Sheet 2

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INVENTOR:

HELNRI COANDA

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Patented Feb. 15, 1938

2,108,652

UNITED STATES PATENT OFFICE

2,108,652

PROPELLING DEVICE

Henri Coanda, Clichy, France, assignor to Soeiete Anonyme d’Etudes des Brevets et Precedes Coanda-Societe Coanda, a corporation ei France

Application January 1®, 1936, Serial No. 55,471 In France January 15,1935

Claims. (Cl. 244—73)

The present invention relates to propelling devices in which there is produced a suction zone in front of the body in motion on which the propeller is mounted, this suction being such that 5 the body in motion is propelled under the influence of the atmospheric pressure existing at the rear of the propeller.

The object of the present invention is to provide a propelling device of this kind which is 10 better adapted to meet the requirements of practice than those made up to the present time. According to the invention the propeller is composed of an annular structure of suitable axial section, on which a ring fits in an adjustable IS manner, said ring being concentric and constructed in such a manner that a very narrow gap is formed between it and said annular structure, through which gap compressed gas escapes outwardly along a frontwardly directed line, the , go axial section of said annular structure consisting of a curve tangent to this line and having its convexity toward the front, while the axial section of said ring is a line making a substantial angle with said first mentioned line.

. Furthermore the ring and annular structure are hollow, at least to a certan depth so as to allow air from the space ahead of the propeller to flow through their central portion and out behind the annular structure. This prevents any suc30 tion at the rear of the annular structure so that the whole of the suction is in front thereof, and the motion of the body is ensured by the difference between the pressure at the front and that at the rear.

Preferred embodiments of the present invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example and in which

Figs. 1 and 2, show in perspective and sectional 40 views respectively a first embodiment of the invention,

Fig. 3 is a sectional view of a modification,

In the embodiment of Figs. 1 and 2. the body of the propelling device according to the inven45 tion includes an inner element ί and a tubular part 2, fitted thereon and provided at 3 with ' screw threads for fixation of a tube 4, This structure carries a series of tubes 5 opening into an annular member 6. Another annular mem50 ber 8 is screwed at 7 on member 6, so that the narrow annular interval 9 between members ® and 8 can be adjusted at will.

Member 6 may be made of a single piece or consist of two rings 6', 6” screwed to each other 55 at 10', fO”.

In the embodiment of Fig. 3, the streamline body i ί contains a part screwed to the member

13. Tubes M are provided in member 13 and secured by the screw thread IS in a ring IS of suitable profile upon which a ring 18 is fixed by 5 screw threads 17, so that this ring 18 can be adjusted in position with respect to ring 16.

Between ring I® and ring 08 there is left an adjustable narrow annular interval 09, ring 18 being however constructed so as to form a cir- 10 cular chamber 20 between said ring and ring 08.

The propeller works in the following manner:

The compressed gas, which may consist of superheated steam or a combustible mixture or some explosive mixture or even compressed air, is 1,5 supplied through tube 4, flows through the annular space formed between elements 1 and 2, passes through tubes $ into the narrow annular interval 9 between the element 6 and ring 8 and escapes into the atmosphere. 20

The fluid film expands and exceeds its initial volume, and, owing to the fact that on one side of the outlet of passage 9, annular member 6 is substantially tangent to the fluid sheet escaping from 9, whereas, on the other side, the edge of 25 member 8 makes a substantial angle to the direction of said sheet, the latter flows along the front face of member 6, following the path indicated by arrows f. Thus in the space marked in dotted lines a rush of fluid is created toward which 30 the surrounding air is drawn in the direction of the arrows f provided the pressure of the motive fluid is sufficient.

Therefore the propeller, owing to the suction created at its front part, has a tendency to rush '35 frontward under the action of the pressure existing behind it, drawing along the structure on which it is mounted provided the outflow is sufficient to create a momentum at low speed and in great masses of the surrounding air, equivalent 40 to the drag of the body in which the propeller is mounted.

Moreover the surrounding air . circulates through the central free portion in the direction of the arrows F, at same pressure, so that be- 45 low the part 6 a counterpressure is created relative to the suction in front of the same, which counter pressure consequently adds to the action of the suction created in front of part a.

The same applies in the case of Fig. 3. The 50 gaseous mixture under high pressure which is to expand after entering the chamber formed by part 12, passes through tube 14, starts expanding in chamber 20 and escapes through annular interval (9 following the front face of element 16, 55

2,108,662 creating in front of it a zone of very strong suction represented by dotted lines.

It is evident that the shape of elements such as 6' and 16 and the thickness of annular inter5 vals 9 or 19 are calculated in such a manner that a certain expansion of the compressed motive fluid permits of obtaining a momentum which ensures the displacement of the body.

In a general manner, while I have, in the above 10 description, disclosed what I deem to be practical and efficient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition 15 and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

It may be noted that in Fig. 1 the member 8 and in Fig. 3 the part 18 extend at least with 20 the edge into a recess at the front of the moving body, with the result that the air or fluid issuing from the narrow slot first strikes the curved portion of the airfoil or wing shaped member so as to follow its curvature forwardly 25 and then outward radially and subsequently rearwardly.