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Feb. 13, 1962 J. H. BERTIN ETAL 3,020,713 THRUST SPOILING DEVICE FOR JET PROPULSIQN UNITS Filed Dec. 9, 1953 United States Patent Q?ice _ 1 3,020,713 3,020,713 Patented Feb. 13, 1962 2 * THRUST SPOILING DEVICE FOR JET PROPULSION UNITS Jean H. Bertin, Neuilly-sur-Seine, and Marcel Kadosch, Paris, France, assignors to Societe Nationale d’Etude et de Construction de Moteurs d’Aviation, Paris, France, a French company Filed Dec. 9, 1953, Ser. No. 397,228 Claims priority, application France Dec. 12, 1952 1 Claim. (Cl. 60-3554) It is known to provide reaction propulsion units with a device for de?ecting the jet, whereby in particular a braking effect is obtained or by reversal of the direction of the thrust. The applicants have themselves proposed, de?ection 15 arrangements which operate by means of a solid or ?uid with a velocity component at right angles to the direction of ?ow of this stream, forms a kind of marginal ?uid screen which masks the openings and displaces the stream away from them. The'said discharge openings for the de?ected jet may thus remain constantly open to the interior of the pro pulsion unit, and it will suf?ce that the auxiliary gas under pressure is blown permanently through the blowing ori ?ce or ori?ces during the periods when there is no de?ec tion; the de?ection is produced by stopping the auxiliary injection and may be furthered by the use of a mobile obstacle ‘which may itself be either solid or ?uid. It should furthermore be noted that the de?ection is facili tated by the fact that the static pressure of the gases of the stream at a point level with the openings tends to produce naurally a ?ow through these openings as soon as the auxiliary fluid screen is suppressed. The description which follows below ‘in respect of the obstacle (in the latter case, a jet of auxiliary gas is in jected into the jet with a component at right angles to the direction of ?ow of the jet) which by modifying the attached drawings (which are given by way of example forces which act on the jet, produce the desired change in 20 only, and not in any way in a limiting sense) will make it direction. Means for guiding the jet thus de?ected, consti quite clear how the invention is to be carried into effect. tuted in most cases by a grid of blades, serve to re-enforce FIG. 1 shows diagrammatically one form of embodi~ the de?ection created by the obstacle. ment of the invention. The upper half and the lower These de?ection devices have been most frequently half of this ?gure are two axial cross-sections of the rear placed at the end of the discharge nozzle, thus increasing 25 portion of a jet propulsion unit taken in two planes at the maximum overall cross-section at this point, which right angles to each other. gives rise to the necessity of a supplementary fairing, ex FIG. 2 is a transverse cross-section along the line II—II tends the length of the casing and has generally an adverse of FIG. 1. In this ?gure, the lines 01 and Ola represent effect on the performance of the aircraft. respectively the outlines of the cross-sectional planes of It would be of great advantage to be able to house the 30 the ‘upper half and of the lower half of FIG. 1. de?ection device in the space within the propulsion unit, FIG. 3 is a diagrammatic view of an alternative em forward of the exhaust discharge nozzle, in a portion of the casing in which there is in general a large amount In the drawing, there is shown at 1, the tubular rear of room available, and this would avoid any increase in portion of a reaction propulsion unit. the maximum overall cross-section as compared with a 35 This tubular portion receives the gases coming from propulsion unit which is not provided with a de?ection the turbine 2. At 3, there is located the exhaust dis device, and which also avoids any increase in the length charge nozzle having a shape adapted for the expansion of the casing, while enabling the provision of grids of of the gases and the formation of the propulsive jet at blades which are more developed in the radial direction, high speed. This discharge nozzle is generally mounted thus increasing the effectiveness of these blades. In order 40 by the aircraft manufacturer immediately after the tube to achieve this, it is necessary to form openings for the 1 of the reaction propulsion unit, at the same time as passage of the de?ected jet, both in the wall of the pro the cowling 4 which surrounds the unit. This cowling pulsion unit and also in the casing, at a point forward of being adapted to the shape of the propulsion unit and of the exhaust discharge nozzle. Since, however, in this the discharge nozzle in order that it shall have a mini zone, the expansion of the gases is not completed, the mumaerodynamic drag, it will be seen that the arrange gases thus having a static pressure higher than atmospheric ment of a de?ection device aft of the discharge nozzle pressure, the problem arises of closing these openings ’ has an adverse effect by varying the aerodynamic .qual bodiment. during normal operation and only causing them to open at the moment when it is desired to de?ect the jet. The ities of the casing. ’ ' . In carrying out the invention, the openings for the de provision of movable mechanical shutters leads to great 50 ?ected jet are formed at a point forward of the discharge complication and di?iculties because of the necessity of nozzle 3. In the form of embodiment shown in the draw causing these shutters to operate in the center of gases ing, these openings are formed by two indentations which at a high temperature. are diametrically opposite and extend parallel to the The object of the present invention is to solve this axis of the propulsion unit, the said indentations being 55 formed both at 5 on the internal Wall of the gas conduit hitherto unsolved problem. forward of the discharge nozzle, and also at 6 in the wall In accordance with the invention, the openings formed of the cowling of the unit. Between the wall of the in the wall of a jet propulsion unit, and in the casing in propulsion unit and the wall of the cowling, they are front of the exhaust discharge nozzle, for the exit of the closedvin by two parallel partitions 7, 8 (see FIG. 2). gases during the de?ection period, are combined with an arrangement of slots or ori?ces formed in the wall 60 They form with these partitions and the walls 9, 10, which are joined to the casing, two channels through which of the jet propulsion unit forward of the said openings, and which are themselves connected to a source of aux iliary gas at a suitable pressure, in particular to the de the gases ofythe jet may escape in the direction shown by the arrows F1 with a component of speed directed towards the front of the unit in order to give a braking livery side of the air compressor of the unit, the said 65 effect. ' ori?ces having a direction such that the auxiliary gas under In these channels, there are arranged grids of blades pressure, injected into the center of the gases of the stream 11, suitably curved’ from the interior of the propulsion 3,020,713 3 unit towards the exterior and forming as many individ ual channels which assist in directing the de?ected jet in the direction F1. Forward of each of the grids of blades, there is provided a curved surface 12 which is connected tangentially both to the internal wall of the gas conduit and to the external wall of the cowling, and which may have an ejector-shaped cross-section as shown in the drawing. Forward of this point, the surface 12 is sepa A. obstacle to the ?ow of the jet of gas towards the dis charge nozzle, and the jet is thus de?ected into the chan nels of the grids of blades, which cause it to escape to the exterior in the direction of the arrows P1. In order to ensure the maximum elfect of the de?ecting jets which are discharged through the ori?ces '14, 15, it is an advantage to provide holes such as 11341, 15a in the wall of the gas conduit aft of the ori?ces 14, 15; these holes enable air to enter and supply the wake created by slot 13, the function of which will be explained in the 10 the de?ecting jets. In order to close-in the channels on each side of the description below. rated from the internal wall of the gas conduit by a Two diametrically opposite holes 14, 15, formed on the wall of the propulsion unit in the plane Ola, perpen grids of blades, the form of embodiment described in cludes the walls 7, 8, which are parallel to each other. This has the advantage that all the portions of the de ?ected jet are directed parallel to these walls, without any lateral component of speed at right angles to the plane of the upper half of FIG. 1. The detachment of the jet from the walls is thus avoided and the jet retains the max shape in the direction of the periphery of the propulsion imum of kinetic energy whilst producing a powerful unit. On the internal wall of the gas conduit, and im mediately forward of the surface 12 respectively, of the 20 counter-thrust. Other arrangements of the outlet channel of the de ori?ces 13 which precede these surfaces, there is formed ?eoted jet may, however, be adopted. a continuous annular slot 18 which connects the interior The ?uid obstacle formed by the jets of air escaping of the propulsion unit with an annular collector 19, the through the ori?ces 14, 15, could be replaced by a solid latter being in turn connected to the delivery side of the obstacle. There could, for example, be provided a di air compressor through a pipe 20 with a wave 21. ametrical support with an aerodynamic pro?le which The operation is as follows: could extend into the discharge nozzle between the points It is ?rst of all supposed that the valves 17 are closed, occupied on the drawing by the ori?ces 14, 15 and which so that the ori?ces 14, 15, are not supplied with air. The would carry movable screens which could be withdrawn gases issuing from the tube 1 of the propulsion unit and into this support, or be caused to project from it; the said proceeding towards the discharge nozzle 3 pass in front solid screens could, furthermore, be replaced by jets of of the passages 5. Since at that point, the gases have a auxiliary gas escaping from slots in the said support. high static pressure, they would have a tendency to es dicular to the median plane OI of the grids of blades, are connected by pipes 16 provided with a valve 17 to the delivery side of the air compressor (not shown) of the propulsion unit. The holes 14, 15, have an extended cape to the exterior if nothing were provided to prevent this. The valve 21 is open and a jet of air passes through the annular slot 18 and penetrates into the interior of There could also be provided a diametrical obstacle 25 turning about a diametrical axis 26 as shown in FIG. 3, the said obstacle occupying either the position shown in full lines for which it presents a pro?led form to the jet of gas, or the position shown in dotted lines, for which angles to the direction of ?ow of the gases. This aux it produces a symmetrical de?ection through the oppo iliary jet compresses the jet of gases ?owing through the sitely-disposed notches in the gas conduit, or any inter tube. It forms around this jet a kind of convergent mediate position giving rise to an asymmetrical de?ection divergent ?uid wall which prevents the gases from escap through the said notches and, in consequence, to a varia ing through the notches 5 and the channels of the grids of blades. The gases are thus led into the discharge tion in the direction of ‘the thrust. The arrangement of the channels for the passage of nozzle 3 without losses, in spite of the absence of any the de?ected jet may be varied. For example the two mechanical shutter on the notches 5. In this phase of the operation, the ori?ces 13 serve to 45 diametrically—opposed channels described, could be re supply the low-pressure zones, or “wake zones” which placed by a single annular channel. Externally, the continuity of the cowling 4, or at least tend to be formed on the outside of the ?uid screen. a part of that continuity, may be restored by' a grid of The ori?ces 13 may be supplied with air by the cooling circuit of the jet propulsion unit or by the special air cross stays in the form of a honeycomb for example, fol inlet openings 22 formed in the cowling. lowing the line 6 outlined in chain-dotted lines in FIG. 1. The operation described naturally supposes that the There could also be provided along this line 6, a movable auxiliary jet is discharged from the annular slot 18 with hood which would only be opened during the de?ection the propulsion unit with a component of speed at right a suitable total pressure. This pressure must be su?icient for the ?uid screen formed around the gases to ensure a balance between the high pressure of the gases and periods; during periods of no de?ection, this hood could not be subjected to the action of the hot gases by virtue of the interposition of the screen formed by the con the ambient atmospheric pressure, until the jet of gas strictive jet. again reaches the full wall of the discharge nozzle. On What we claim is: the other hand, it must not be too high, since in this case, In a jet propulsion unit ending with a propulsive nozzle the excessive contraction of the jet of gas would lead designed for expanding motive gas and having a pipe con to an aspiration of the exterior air through the channels 60 meeting said propulsive nozzle for conducting thereto a of the grids of blades. As, at the delivery of the com stream of motive gas, a thrust spoiling device comprising pressor of the jet propulsion unit there is available a passage means at the periphery of said pipe upstream of pressure very much higher than the pressure of the gases said propulsive nozzle, said passage means extending laterally of the normal axial ?ow path of said stream and in the portion 1, the gases having passed through their ?rst expansion in the turbine, it will be possible to vary 65 opening into the atmosphere at a substantial angle with the axis of said nozzle, to provide an auxiliary de?ected the pressure and/or the output of the gases passing exhaust path for said stream, blowing means extending at through the slot 18 in order to achieve the desired effect. the periphery of said pipe and opening thereinto upstream If now it is desired to de?ect the jet, the valve 21 is of said passage means, said blowing means being designed ?rst closed in order that the ?uid screen shall cease to exist and the gases already have a tendency to pass out to 70 for forming a screen-like ?uid partition about the motive gas stream past the passage means, means for supplying the exterior through the channels of the grids of blades. pressure ?uid to said blowing means, controllable means The valves 17 of the conduits 16 are opened. Two jets for cutting off the supply of pressure ?uid, means for col of air thus pass out through the opposed ori?ces 14 and lecting ambient air and means for leading said ambient 15 in the diametrical plane at right angles to the median plane of the grids of blades. These jets tend to form an 75 air to a point of the pipe located between the blowing 5 3,020,713 8 means and the passage means, whereby the low-pressure wake zone which tends to arise at the side of the fluid partition opposite to the screen is ?lled with air. 2,7 02,986 2,793,4931 Kadosch et a1. ________ __ May 28, 1957 1,020,287 France ______________ __ Nov. 12, 1952 Kadosch et a1. ________ __ Mar. 1, 1955 FOREIGN PATENTS References Cited in the ?1e of this patent UNITED STATES PATENTS 2,418,488 2,692,800 Thompson __________ __ April. 18, 1947 Nichols et a1 ___________ __ Oct. 26, 1954 6 OTHER REFERENCES “Anti-Bomber Rocket Missiles,” by Chandler Aero Digest, April 1950, pages 100—102.