US2540594A - Ram jet engine having variable area inlets - Google Patents

Description

Feb. 6, 1951 N. c. PRICE RAM JET Enema HAVING VARIABLE AREA INLETS' Filed Aug. 23, 1946 s sheets-sheet 1 m om m mm R g H .F L a INVENTOR. NATHAN C. PRICE ow on ill! E) Feb. 6, 1951 N. c. PRIICE 2,540,594

RAM JET ENGINE HAVING VARIABLE AREA INLETS Filed Aug. 23, 1946 8 Sheets-Sheet 2 Feb. 6, 1951 N, 3, PRICE 2,540,594

RAM JET ENGINE HAVING VARIABLE AREA INLETS Filed Aug. 25, 1946 8 Sheets-Sheet 3 NOZZL THROAT G m A7MOSf/IERE IN VEN T OR.

NATHAN C. PRICE Agent Feb. 6, 1951 N. 0. PRICE RAM JET ENGINE HAVING VARIABLE AREA INLETS Filed Aug. 23, 1946 8 Sheets-Sheet 4 hm mm INVENTOR. NATHAN 0. PRICE o r :1 f II a W mm 8 m v ms H Agent Feb. 6, 1951 c, PR|CE 2,540,594

RAM JET ENGINE HAVING VARIABLE AREA INLETS Filed Aug. 25, 1946 8 Sheets-Sheet 5 VINVENTOR. NATHAN C. PRICE 2 Agent Feb. 6, 1951 N. c. PRICE I 2,540,594

RAM JET ENGINE HAVING VARIABLE AREA INLETS Filed Aug. 23, 1946 8 Sheets-Sheet 6 INVENTOR. NATHAN C. PRICE 2 Agent Feb. 6, 1951 N. c. PRICE RAM JET ENGINE HAVING VARIABLE AREA INLETS 8 Sheebs-Sheet 7 Filed Aug. 23. 1946 vm H m I w a 3:56 zoEwawiou mN a V I 7%7/1/515...

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INVENTOR. NATHAN C. PRICE {IIIIIIII/lj I Ageni Feb. 6, 1951 N. c. PRICE 2,540,594

RAM JET ENGINE HAVING VARIABLE AREA INLETS Filed Aug. 25, 1 46 a Sheets-Sheet a Much No, LO

Mach No. L4

Mach No. 2.0

Much No. 2.5

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Much No. 3.0

INVENTOR. NATHAN C. PRICE Patented Feb. 6, '1951 I UNITED STATES PATENT OFFICE RAM JET ENGINE HAVING VARIABLE AREA INLE'I'S Nathan 0. Price, Los Angeles, Calif., asaignor to Lockheed Aircraft Corporation, Burbank, Calif.

Application August 23, 1946, Serial No. 692,423

30 Claims. (01. so-'-s5.e)'

This invention relates to reactive propulsion engines or power plants, and relates more particularly to ram jet engines having variable area inlets useful in the propulsion of missiles and high velocity aircraft. In the propu sion of aircraft and airborne missiles, speed and altitude are factors which limit the efficiency and practicability of reciprocating engines, and beyond certain speed and altitude limits, the efficiency of the reciprocating engine drops to the point that it is no longer practical as a means of propulsion. The turbo-jet reactive propulsion power plant is effective at velocities and altitudes beyond those obtainable with the reciprocating'engine, but the turbo-jet unit a so has its speed and altitude limitations. The so-called ram jet type of engine, to which the present invention relates, is practical and efficient at speeds and altitudes far above those at which either the reciprocating engine or turbojet unit can operate. Accordingly, the'ram jet engine extends the speed and altitude capabilities of aircraft and airborne missiles.

It is an object of this'invention to provide a practical efiective ram jet engine embodying a variable control means operating to automatically govern the ram air in et difluser to obtain efflcient compression at various altitudes and velocities of operation. The power [plant employs an adjustable needle in the convergent-divergent inlet diffuser which is automatically moved axial- -ly in response to velocity variations to produce and utilize series of reflected shock waves of low or medium intensity to obtain a greater efliciency of compression than is possible with a single severe shock wave. The area or zone of convergence of these reflected shock waves is a region of high compressibility in the ram in et, and the control means of the invention utilizes the position of this zone of convergence as a factor or index for determining the needle position to obtain optimum compression at various velocities. The automatic adjustment or regulation in the position of the needle affords efficient compression at different speeds in the supersonic range of flight or engine operation.

Another object of the invention is to provide a ram jet power plant characterized in (part by a fuel system maintaining a substantially constant air-fuel ratio in the combustion chamber, irrespective of both the translationa speed and altihide. The fuel system may employ a centrifugal pump driven by an air turbine, which in turn is driven by the rammed air column. At a Mach number of approximately 3.0, the spouting velocity of the reactive power plant is approximately twice that of the translatory velocity, bringing the point of maximum thrust into coincidence late the fuel system to obtain practically any required thrust at various speeds.

It is another object of the invention to provide a ram jet power plant which effects full thermal vaporization ofthe fuel prior to its introduction. into a constant pressure type combustion chamber, at a multiplicity of shielded injection orifices located adjacent the entrance of the combustion chamber so as to effect a uniform dispersion of the vaporized fuel across the air stream. The

vaporizing and injecting means are constructed and arranged to obtain maintained flame propagation and eflicient fuel combustion at the various speeds of operation.

Another object of this invention is to provide a ram jet unit of the character referred to having a nozzle throat member automatically adjusted or moved in the supersonic propulsive nozzle of the engine to control the nozzle area and thus obtain a desirable relation between the critical nozzle throat pressure and the initial combustion chamber pressure at given nozzle velocities. An automatic means moves the throat member upstream against the force of the gas pressure tending to move the member downstream and the automatic action preserves or substantially preserves the most efficient relationship between the nozzle throat pressure and the combustion chamber pressure.

Another object ,of the invention is to provide a ram jet power p ant of the character above referred to in which the several operative elements and controls are so constructed and related as to constitute a compact power plant unit of high efflciency having a minimum of external parts and projections which might produce aerodynamic drag in the event the unit is arranged for operation in a free air stream; for example, at the wing tip of an airplane.

A further object of the invention is to provide a ram jet engine capable of producing great thrust power in relation to its weight and that is capable of multi-sonic velocities.

A still further object of the invention is to provide a power plant of the class, referred to that is simple and inexpensive to manufacture, having but few working parts so as to be adapted for embodiment in expendible units such as guided missiles.

Other objects and features of the invention will a be readily understood from the following detailed with that required for maximum range and best.

efliciency. To obtain fuel economy at lower Mach numbers, the fuel system is automatically controlled .by .a connection with the inlet diffuser needle and provision is also made to set or resuview of the forward. portion of the power plant longitudinal sectional I showing the ram inlet needle in its retracted position;

Figure 4 is a longitudinal detailed sectional view of the island portion of the unit illustrating certain controls and showing the fuel pump and air turbine;

Figure 5 is an enlarged longitudinal sectional view of the nozzle portion of the unit;

Figure '8 is an enlarged front view of the device;

Figure '1 .is an enlarged detailed sectional view taken substantially as indicated Fi ure a Figure 8 is a perspective view of a' portion of the fuel vapor injecting system;

Figure 9 is a transverse detailed sectional view taken as indicated byline 2-! on Figure 3;

Figure 10 is a fragmentary sectional view of the forward portion of the unit with the needle appearing in side elevation in its most forward position:

-l 'lgure 11 is a fragmentary sectional view illustrating one of the stabilizing strips of the fuel vaporizing tube assembly. the section being taken as indicated by the line II-II on Figure 2;

Figure 12 is a diagrammatic view illustrating the several controls embodied in the power plant: and,

Figures 13 to l"! inclusive are fragmentary die.- grammatic views illustrating the manner in which the reflected shock waves converge in the inlet ram with the inlet needle in various positions.

by line 1-1 on section connected intermediate the ram and the combustion chamber section I2. An internal re-r inforcing hoop II! is secured in the rear end of the ram II by screws or bolts I8 and the section It telescopes over the hoop to be secured to the hoop and ram by welding I1. The section It is slightly rearwardly divergent or flared to continue the contour of the inlet ram II The tubular section It houses and supports certain controls and internal parts to be later described.

The combustion chamber section I2 may be a simple tubular part of uniform diameter throughout and is formed of corrosion resistant and heat resistant material such as Inconel." or the like. As illustrated. the section I2 is of substantial length in relation to the other parts of the shell A to deflne'an elongate passa e or chamber of reinforcing hoo I9 is secured in the rear the several sections II, I2, I2 and ll of the shell The ram iet power plant of the invention may a be said to comprise the combination of the following elementsz' a bod or shell A having an inlet ram II and a nozzle I3, an inlet needle B. a stationary island 0 within the shell A. an automatic variable control means D for the needle 3, a fuel vaporizing and injecting system E. an automatic and regiilable control means F for the fuel system and an automatic control G for the propulsive nozzle I8.

The shell A which constitutes the body of the power plant is an elongate tubular element adapted to move in an air stream or to be submerged or partially submerged in the structure of an aircraft or guided missile. As illustrated. the major portion of the shell A is cylindrical or of uniform diameter, and the shell serves to house or contain the various other components of the engine, it being a feature of the invention that there is no necessity for protruding parts or assemblies which may ofler drag or resistance to flight. In the preferred form of the invention the shell'A comprises three main parts. the inlet ram II, a combustion chamber section I2 and a nozzlesection I3. These parts may be integral. although I may prefer to construct them as separately formed'elements to facilitate fabrication and assembling.

The inlet ram II of the shell A is of the supersonic type and is in the nature of a tubular convergent-divergent diffuser type inlet controlled by the internal variable-position needle B to be subsequently described. The forward edge of the ram II is sharpened to offer a minimum of drag, and where the plant is designed for use in a free air stream, its external surface is smooth, regular and of gradually increasing diameter to reduce the drag to a minimum. The internal surface of the ram II also gradually increases in diameter and is smooth and free from irregularities. I prefer to construct the rear part of the inlet ram as a separate section I l. which may be considered either as a. portion or the ram I I or as a suflicient extent to assure full combustion of the vaporized 'fuel. The forward extremity of the section I2 is Joined to the rear end of the section ll by a con inuous weld It. An internal part of the section I2 by screws or bolts 2..

The nozzle or nozzle section It is a tubular part which telescopes over the hoop I9 and is join d or connected with the same by a continuous weld In this connection, it will be obs rved that A are integrally or ri idly joined to be free for expansion and contraction as a unit under temperature changes, there being no joints or seams where relative movement occurs b reason of thermal differentials. The nozzle section It is in the nature of a supersonic propulsive nozzle for ejecting the gases of combustion and the heated air at sonic and superson c velocities. The forward portion of the section It may be of the same diameter as the section I2. An intermediate and somewhat rearward portion of the section It is shaped or contoured at 22 to curve rearwardly and inwardly toward the longitudinal axis of the assembly, and to then curve rearwardly and outwardly at 23 to a subs antially cylindrical terminal wall 24. The curved portions 22 and 23 provide a restricted nozzl throat, the effective area of which is controlled by the nozzle member I08, to be later described. The internal surface of the nozzle section It is preferablycovered or painted with ceramic paint or other heat resisting material, and the section may be formed of Inconel, or other heat resistant alloy.

The annular external depression formed by the nozzle throat ,walls 22 and 23 is utilized to receive a mounting ring 25. The ring 25 may have the same external diameter as the combustion chamber section l2 and the forward portion of the section I3, and is secured to the section It spacing blocks 21. One or more lugs 28 are provided on the ring 25 to mount the engine; and a link 29'. is connected between the lugs and a support (not shown) to permit free thermal expansion and contraction of the engine with respect to its supports. One or more mounting lugs 30 are secured to the above described reinforcing hoop I5, and project from the shell A to assist in mounting the engine.

The control for the rammed air inlet and diffuser Il comprises the movable needle B in the inlet passage, the position of which is varied to control thecompressive efiect at the various translational velocities. The needle Bis centrally and axially positioned in the ram inlet passage, and is movable with respect to a hollow stationary structure, which I have termed the island 0. The needle and island together constitute an elongate streamlined assembly capable of elongation and contraction to govern the'compressive ram action. The needle B comprises a harp pointed forward tip 40, and a tubular or. hollow wall 4| extending rearwardly from the tip to have its rear portion telescope over the island. The wall 4| as illustrated, curves rearwardly and outwardly from the tip 40, it being understood thatthe active surface of the needle may be comprised of a series of angular or conical surfaces of progressively increasing mean diameter. The curve or angle of the needle surface is of importance in causing the reflection of relatively'gentle shock waves of air toward a limited area of the internal surface of the ram A. The lines 42 in Figures 3, and 14 to 17 inclusive, indicate the reflected shock waves with the needle in the various positions it assumes at the different velocities of flight. It will be observed that forward and aft movement of the needle B moves the region of convergence of the shock waves forwardly and rearwardly along the interior of the ram A. The angulation or configuration of the needle is such that the reflected shock waves converge in a region of rather abrupt pressure rise adjacent the forward end of the ram. The concentration of the shock waves is utilized as a factor or medium of control, as will be later described in connection with the control means D. The rear portion of the needle shell or wall 4| is slightly curved or convex to carry out the streamlined configuration of the needle and island assembly. An internal partition or pressure bulkhead 44 is fixed in the needle some distance rearwardly of the tip 40 and is preferably partially spherical to present a concave rear face.

The island C is a hollow assembly stationarily supported in the inlet portion of the tubular shell A, and comprises a tubular forward section 45 and a rearwardly converging conoidal rear section 46. The island is supported by spaced struts 41 of streamlined cross section, which are secured to the interior of the shell section l4 and welded or otherwise attached to the island section 45. The struts are hollow or tubular to contain certain conduits to be later described, and the section 46 is ported to place the struts in communication with the interior of the island. A domed cap 49 is provided on the forward end of the island C and is freely received in the needle B. The trailing edge portion of the needle carries a sealing ring and bearing 48 which slides on the exterior of the cylindrical island section 45 to assist in guiding the needle for axial movement and to seal off the interior of the needle. The means for shiftably supporting and guiding the needle B further includes a tubular shaft 50 secured in a central opening in the cap 49 and passing forwardly through an opening 5| in the bulkhead 44. A sliding seal is preferably provided in the opening 5| to prevent excessive leakage of air pressure through the opening. The needle tip 40 is socketed to freely receive the shaft 50 when the needle is in its rearmost position.

The automatic variable control means D for the movable inlet needle 50 governs the position of the needle in the inlet passage to obtain a most efficient compression ratio at the various speeds of operation and at different altitudes. The control system is characterized by its simplicity and fully automatic operation. It includes a sealed diaphragm chamber 52 contained within the cap 49. A- flexible diaphragm 53 passes through the communicates with the atmosphere.

chamber to divide its interior into two parts as shown in Figure 12. The diaphragm serves to control an air-pressure bleed or vent passage 54 leading from the exterior of the shell A where it It will be observed-that the pressure bulkhead 44 and seal 48 close the opposite ends of a space withinthe needle B. The volume of this space is markedly reduced or lessened by the closed island section 45 and its cap 49 which together occupy the major portion of the interior of the needle. Apressure air port 55 in the wall of the needle section 4|, adjacent its rear end, maintains this space of limited volume in communication with the pressure air inlet passage of the ram. Thus the internal surface of the somewhat conoidal needle section 4| and bulkhead 44 are subjected to ram air pressure which tends to move the needle forwardly, this action being governed by controlling the vent passage 54.

The above mentioned diaphragm 53 carries or operates a sliding piston and valve 55,, which controls the inlet 51 of the air vent passage 54. The outer end of the piston-valve 56 is exposed to and acted upon by the pressure in the interior of the needle B, the pressure tending to move the piston-valve to an open position where the pressure-air may bleed out through the vent 54.

The diaphragm 53 is in turn sensitive to or actuated by the position of convergence and intensity of the shock waves 42 reflected toward the inner wall and the ram II by the needle B. A tube 58 extends from the rear side of the diaphragm chamber 52 through one of the struts 41 and along the exterior of the shell A to the forward end portion of the ram inlet II where it communicates with the inlet passage at 9. A similar tube 59 extends from the forward side of the diaphragm chamber 52 to the forward portion of the ram inlet where it communicates with the inlet passage at a point 8 some distance rearwardly from the point 9 of communication of the tube 58 with the passage. In practice, the point 8 may be in any suitable location at the rear of the point '9. The space or area adjacent the open forward end 9 of the tube 58 is the zone traversed by the converging shock waves 42 during movement of the needle B between its extended and retracted positions accompanying variations in the velocity of flight.-

The control D just described serves to move the needle B forwardly as the forward speed of the engine increases and moves the needle rearwardly as engine speed decreases, thus affording efficient compression of the air by the ram action at different speeds in the supersonic range. Figures 13 to 17 depict in a diagrammatic and generalized manner, the position of the needle B, and the position and character of the shock waves 42 during various translational velocities of the power plant. At the initiation of engine operation, the needle B is in its rearmost position, and as the speed of the engine increases, the needle is moved forwardly by the air pressure building up in the interior. This forward movement of the needle continues until the needle reaches a position where the reflected converging shock waves 42 move rearwardly beyond the tap 9 to substantially decrease the pressure in the tube 58 and the rear 'side of the diaphragm chamber 52. Thereafter, the position of the needleB is determined by the equilibrium of pressures on the internal and external surfaces of the needle, this equilibrium being dependent upon engine speed; i. e., transiatory velocity. The action 'of the needle B and its control is described in more detail below.

New referring to Figure 13, it will be assumed that the engine is traveling at the speed of sound or a speed approaching the speed of sound; for example, at a Mach number of 1.0. At this speed the needle B is in its rearmost position, the pressure admitted by the bleed 55 to the interior of the needle being insuflicient to move the needle forwardly. No shock waves are formed at this velocity but a bow wave I40 is formed in front of the needle B and the engine. In Figure 14 it may be assumed that the power plant has exceeded the speed of sound, traveling at a Mach number of 1.4, and the initial shock wave 42 is reflected from the needle B at an angle of approximately 45 to the longitudinal axis of the needle. This initial shock wave may or may not impinge against the lip portion of the ram inlet H. Although the pressure within the needle B and in the forward side of the diaphragm chamber 52 is building up at this time, it has not reached a value suflicient to move the needle forwardly. When the engine attains a higher velocity, say a speed equivalent to a Mach number of 2.0, by its own propulsive force, or with the assistance of rocket power or the like, the pressure admitted to the interior of the needle B by the port 55 moves the needle forwardly against the action of the ram pressure. Thus in Figure 15 the needle has moved forwardly to a position where the reflected shock waves 42 impinge against the internal lip portion of the ram l I in the vicinity of the tap 9. It will be observed that the automatic forward adjustment of the needle B effects utilization of the several shock waves 42 produced at this speed by bringing them within the entrance of the ram H and an efficient compression of the air is obtained. The area of convergence of the shock waves 42 adjacent the tap 9 constitutes a region of increased pressure; however, the pressure at the tap 8 is always greater than the pressure at the tap 9. The line 59 carries this greater pressure to the front side of the diaphragm 53. This pressure admitted by the line 59 opposes the tressure within the needle B acting on the piston 56 and opposes the pressure admitted to the diaphragm chamber 52 by the tap 9 and line 58. When the pressure acting on the front side of the diaphragm overcomes the pressures on its rear side, the piston 56 moves rearwardly to limit bleeding of pressure air from the vent 54. When the angles of the shock waves are decreased further, due to additionally increased engine speed, their point of convergence moves rearwardly away from the pressure tap 9, thus reducing the pressure at the rear side of the diaphragm 53. As a result, the diaphragm 53 moves to the rear and the piston-valve 56 closes or further restricts the bleed 54 so that pressurebuilds up within the needle B to move the needle forwardly. This forward movement of the needle returns the point of convergence of the shock waves to the vicinity of the tap 9 to terminate forward movement of the needle. In practice the diaphragm 53 will assume a condition of equilibrium to stabilize the needle B in proper adjusted position for any given velocity of the engine. In Figure 16 is may be assumed that the unit has attained a speed equivalent to a Mach number of 2.50 and the resultant increase in the pressure on ram-compressed air admitted into the needle B by the port 55 has moved the needle forwardly. This forward adjustment of the needle causes the shock waves 42 of proportionately increased Mach number to be reflected 76 utilization of the gentle shock waves.

in a manner to converge adjacent the tap 9 or in the region between the taps 8 and 9, thus pregserving the eflicient compression-obtained by the It will be observed that as the speed of the power plant increases. the angles of the shock waves 42 with relation to the longitudinal axis of the needle B are decreased, and the forward automatic adjustment of the needle compensates for this change in angularity to keep the area of convergence of the shock waves within the adjacent forward lip of the ram I I. As with the earlier speeds, the ram-compressed air admitted into the needle B is increased to move the needle forwardly and the pressure in the forward side of the diaphragm chamber is also increased. However, this increase in the pressure acting on the forward side of the diaphragm is opposed by the same pressure acting on the piston 56 and by the increased air pressure admitted to the rear side of the diaphragm by the tap 9 and line 58. As a result, the piston 56 serves to control the bleed of air pressure from the needle so as to maintain the needle in its adjusted location. Figurel'? illustrates the position of the needle B when the power plant has attained a Mach number of 3.0 and shows the needle in an advanced position where it directs or reflects the shock waves 42 so as to converge in a region adjacent the tap 9 or between the taps B and 9 so as to preserve the efficient compressive action at the higher velocity. The diaphragm control acts to retain the needle B in this position so long as the velocity is preserved. When the speed of the engine is reduced, the needle B automatically moves to the rear as will be readily understood, the diaphragm control serving to cause such movement of the needle in proportion to the reduction in velocity. This maintains the area of convergence of the shock waves 42 within the lip portion of the ram l I; i. e., between the pressure taps 8 and 9.

, The fuel system E effects thermal vaporization of the fuel and injects the vaporized fuel into the airstream at the forward end of the combustion chamber. The system includes fuel pump means for delivering liquid fuel under pressure to a vaporizing means. The pump is preferably contained in the island C and is driven by an air turbine at the rear portion of the island. I have shown a fuel supply pipe 60 passing inwardly through one of the struts 41, from a fuel source (not shown), and provided with an elbow 6| having a. rearwardly extending arm which is substantially co-axial with the island assembly. A centrifugal fuel pump 62 has its inlet or low pressure side connected with the elbow 6| and its high pressure side delivers fuel to pipes 63 extending outwardly and rearwardly through the struts 41. The shaft 64 of the pump is tubuiar, and is supported by spaced bearings 65 carried in a housing 66. The housing 66 has an outwardly extended peripheral flange 61 con-- tinuing rearwardly from the wall of the island and provided with spaced lugs 68 bolted to a surrounding shroud 69. The shroud in turn is carried by the spaced struts 41. and the shroud 69 define an annular rearwardly converging air passage 10 which is co-axial with the main air passage of the power plant. A

substantially conical cap H is secured in the shroud in spaced relation to its internal surface to provide or leave a rearward continuation of the passage 10. This continuation of the passage is of rearwardly increasing capacity. Spaced. rivets or bolts" may mount the can" inthe The flange 61 a shroud 88. The cap II is spaced rearwardly from the housing flange 81 to leave an annular gap for an air turbine wheel 18. The wheel 13 is fixed to the pump shaft 64 and its blades operate in the air passage 18. The structure just described is best illustrated in Figures 3 and 4. It will be seen that air under pressure flowing through the passage 18 at a substantial velocity drives the turbine wheel 13, which in turn drives the fuel pump 82. The entrance of the annular passage 18 surrounds the aft or trailing portion of the island, and serves as a means for sucking away or removing the boundary layer air from island and needle B. This substantially increases the efilclency of the supersonic inlet ram or convergent-divergent inlet diffuser.

The vaporizing means of the fuel system E is associated with the combustion chamber to utilize the heat of combustion to vaporize the fuel before it is delivered to the injecting means. The lines 63 from the pump 82 lead through the struts 41 to an annular and tubular header 14 engaged within the shell section H and associated with the struts 41; see Figure 3. A similar header 15 is arranged rearwardly of the header 14, the two members preferably being substantially square in transverse cross section and secured in abutting relation. A third manifold ring or header 16 of similar configuration is so. cured in the rear portion of the combustion chamber section i2 adjacent the above described hoop l9 as shown in Figure 5. A series of circumferentially spaced vaporizing tubes 11 have their forward ends in communication with the fuel supply header 14 and pass rearwardly through openings in the walls of the header 15. The tubes 11 continue rearwardly in spaced adjacent relation to the wall of the combustion chamber section I2, andhave their rear ends received in openings in the wall of the rear header 16. A similar set of tubes 18 have their forward ends in communication with the fuel receiving header l and their rear ends are in communication with the rear header 18. I prefer to alternate the tubes 11 and 18 in a single tubular or annular series as illustrated. It will be apparent that fuel supplied to the header 14 by the pump 62 flows rearwardly through the tubes 11 and then forwardly through the tubes 18 to the header 15, and during this circuit the fuel is effectivoly vaporized. The tubes 11 and 18, and the manifolds 14, 15 and 16 are preferably formed'of corrosion and heat resistant material such as Inconel," and strips 88 of the same or similar material are laced around or through the annular series of tubes 11 and 18 at spaced points to stabilize the tubes. Figure 11 illustrates the manner in which the strips 88 are trained between the adjacent tubes.

The fuel vaporized in the tubes 11 and 18 is delivered to vapor injection devices arranged in the forward portion or entrance of the combustion chamber. These devices are best illustrated in Figures 3, 7, 8 and 9. A plurality of circumferentially spaced tubular struts or bars 8| extend radially inward from the vapor header 15 and are spaced between the supporting struts 41. Partitions 82 in the rear portions of the struts 41 define vapor passages 83 therein. The inner wall of the tubular vapor header 15 has spaced ports 84 which communicate with the interiors of the bars 8! and passages 83 to deliver vapor thereto for inward flow to the injectors.

The injectors comprise what I will term cup strips 84 arranged on the bars 8| and struts 41. The cup strips 84 are preferably arranged in concentric radially spaced annular rows as shown in Figure 9, and although the strips may be provided in two or more spaced transverse planes, I have shown all of the strips in a single transverse or diametric plane. The cup strips 84 are curved or arcuate and are substantially U-shaped in transverse cross section. having curved forward end walls and spaced substantially parallel or concentric side walls which extend rearwardly relative to the direction of air now. As shown in the drawings, the cup strips 84 are secured intermediate their ends to the struts 41 and bars 8| so that their side walls extend freely beyond the struts and bars, both in the rearward and circumferential directions.

Each circular row of cup strips 84 embodies a multiplicity of the strips related to have their ends in spaced adjacent relation whereby their Interiors are, in effect, in communication but the individual strips are free for independent thermal expansion and contraction. The several circular rows of cup strips 84 are spaced and related as shown in Figure 9 so that the outer row is adjacent the wall of the shell A, and the inner row is in spaced surrounding relation to the above described shroud 68. The vaporizing strips are secured to the struts 41 and bars 8| by welding, or the like, so as to be rigid and stationary. Ports 85 are provided in the walls of the bars 8| and struts 41 to deliver fuel vapor to the interiors of the cup strips 84, and the inner ends of the bars and passages 85 are open to the innermost strips. This vapor travels or flows circumferentially in the cup strips and moves axially or downstream. In order to prevent stagnation of the vapor in the strips 84, and to assure a more complete and uniform combustion of the vapor by means of controlled primary combustion, I provide a series of spaced ports or openings 86 in the forward walls of the strips. The capacity and spacing of these openings 86 are such that the flames are not extinguished by the air admitted by them into the interiors of the cup strips. It will be seen that the vapor injecting means provides and maintains an extensive and uniform dispersion of fuel across substantially the entire air stream at the entrance of the combustion. chamber. The struts 41, bars 8| and cup strips 84 are preferably constructed of Inconel, or the. like.

Means are provided for igniting the fuel vapor at the injection system just described. As best shown in Figure '7, a glow plug 82 is threaded through a boss 81. on the shell A and passes inwardly through openings in the shell and header 15 to project into one of the hollow bars 8|. The resistance wire of the glow plug for igniting the fuel is housed in a perforate shield 88. A liquid fuel line 88 enters the shell A and has a jet 98 directed to impinge a stream of fuel against the shield and glow plug. A short tap or pipe 9| leads from the interior of the liquid fuel header 14, and is arranged to direct a small stream of fuel against the shield and glow plug. A flame initiated at the glow plug travels out through the bar 8|, and the openings 85, and progresses through the several cup strips 84 to ignite the fuel in the strips. In practice, fuel from the pipe 8| will usually be employed to start the engine. However, in the case of certain fuels of low inflammability, and under difficult starting conditions, additional fuel or special fuel may be supplied through the pipe 98 to assist in starting. The fuel vaporizing and 11 injecting system and the igniting means just described form the subject matter of my copending application Serial Number 783,536, filed November 1, 1947.

With the fuel vaporizing and injecting means E described above, the air-fuel ratio remains substantially constant, irrespective of the translational speed and altitude, the centrifugal fuel injecting pump 62 being driven by the rammed air supply through the medium of the turbine 13 to preserve this ratio. The fuel pump 92 and turbine I3 are related and designed to provide an air-fuel ratio of approximately 18 to one. When the translational movement of the engine reaches the value of a Mach number of approximately 3, this air-fuel ratio causes the spouting velocity of the air and gases of combustion from the nozzle I3 to be approximately twice that of the translational velocity, bringing the point of maximum thrust into coincidence with that required for maximum, range of flight and best economy. At lower flight Mach numbers the air-fuel mixture should be leaner, although it may be important and desirable to obtain maximum thrust under certain conditions at such lower velocities. It may also be necessary to vary the thrust at any velocity of flight. The control means F is provided to permit regulation or variation of the thrust as may be required regardless of fuel economy. The control means F is in the form of a controlled by-pass system between the low pressure pipe 60 of the pump 62 and one of its high pressure pipes 63. The by-pass 93 has a nozzlelike part I50 in the fuel supply pipe 60 arranged to discharge the by-passed fuel downstream or in the direction of fuel flow. This positioning of the part I50 prevents cavitation at the pump 62. An adjustable constant flow valve is interposed in the by-pass 93. This valve includes a stationary island 94 of streamlined configuration arranged in the path of fuel flow and a floating tubular venturi 95 movable toward and away from the island so as to cooperate therewith in restricting the fuel flow through the bypass 93 to a greater or lesser degree. The Venturi member 95 carries a piston 93 operating in--a cylinder 91 connected in the by-pass line 93. The passage 98 of the Venturi member 95 continues through the piston 96, having its entrance mouth at the upstream side of the piston and its exit in opposed relation to the island 94. Relatively small ports 99 lead from the restricted throat of the Venturi passage 99 to the downstream side of the cylinder 91 to balance the pressures on the opposite sides of the piston. It will be seen that with the valve structure just described the Venturi member 95 is constantly urged toward the island 94, by the fuel flow, to restrict the flow.

The fuel control means F serves to govern or regulate this tendency of the Venturi member 95 to move toward the closed position, and thus regulates fuel flow the by-pass 93I A rod I00 is connected with the upstream end of the piston 93 and extends from the cylinder 91 to have its outer end connected with a tension spring IN.

The spring IOI is in turn connected with a rocker or lever I 02 at a point intermediate its ends. The lever or rocker I02 has one end fulcrumed at I03 to a member I04, which is capable of adjustment or setting in any selected position. Al-

though any appropriate means may be provided to adjust the member I04, I have shown a Bowand extending forwardly for connection with a clip I01 0n the bulkhead 44 of the needle.

It will be seen that with a given setting of the fulcrum control member I04, forward motion of the needle B accompanying increased velocity of flight moves the rocker I02 to reduce the tension in the spring IOI, allowing the Venturi to move toward the island 94, thereby reducing the fuel flow through the by-pass 93 and increasing the delivery of fuel to the combustion chamber up to the value required for eflicient engine operation. When the needle B moves rearwardly at a reduced Mach number of engine operation, the rocker I02 is moved to increase the tension in the spring IOI and thus move the venturi away from the island 94 to allow increasedflow through the by-pass 93, reducing the delivery of fuel to the combustion chamber. The regulable fulcrum member I04 and its associated manual, mechanical or remote control forms an overriding regulation for the fuel by-pass system. When the member I04 is moved forwardly, the tension in the spring IN is reduced to lessen fluid flow through the bypass 93 and accordingly increase the delivery of fuel to the combustion chamber and obtain a greater thrust. Conversely, when the member I04 is moved to the rear, tension in the spring IN is increased, moving the venturi 95 away from the island to allow an increased fuel flow through the by-pass and therefore reduce the delivery of fuel to the combustion chamber. It will be observed that the out-put or thrust of the engine can be regulated independently of the automatic control by merely changing the position of the fulcrum member I04,

The control G for the propulsive nozzle I3 includes a throat member I08 movable in the nozzle and a mechanism or control for automatically shifting or adjusting the throat member. The throat member I09 is preferably a tubular or hollow element formed of heat resistant material such as a ceramic material. The major portion of the member I00 is preferably substantially spherical to obtain a most efllcient action in the supersonic nozzle I3, while the rear portion of the member is extended and defined by a reverse curve. The nozzle or throat member I00 is slidably or-shiftably supported on a central tube I09 secured in the rear end of the above described shroud 69 and extending rearwardly through the combustion chamber to the extremity of the nozzle I3. The tube I09 serves to conduct the air under pressure which has been exhausted by the turbine I3 and shroud 69, and

scribed below. The tube I09 is formed of heat 13 resistant material and is preferably painted with ceramic paint.

The throat member I08 has a pin and slot connection with the tube I00. Axial slots IIO are formed in diametrically opposite wall portions of the'tube and a rod III carried by the throat member extends through the slots. A tubular spacer H2 is provided on the rod within the tube I03. It will be observed that the slots IIO maintain the interior of the throat member I08 in communication with the tube so that cooling air is free to flow from the tube into the member. A seriesof spaced ports I I3 pass'through the rear wall portion of the throat member to exhaust the cooling'air and thus maintain a circulation of air through the member. Furthermore, the sliding fit of the throat member I08 on the tube I03 may be such as to allow the limited escape of cooling air under pressure to further assist in maintaining an air flow through the member. From the above it will be seen that the exhaust of the air turbine I3 is utilized to cool the tube I03, the throat member I08 and the parts associated therewith.

It is desirable to provide a means of support for the tube I09 in the rear portion of the engine. I have shown two spaced struts I I4 secured to the tube as by welding, and suitably attached to the wall of the nozzle section I3 to carry the rear portion of the tube. The struts I I4 are preferably streamlined in transverse cross section, and are tubular. As shown in Figures 5, the struts II4 have their interiors in communication with the tube I09 to receive cooling air therefrom, and the outer ends of the tubes are open to discharge into the atmosphere. During operation of the power plant there is a continuous flow of cooling air through the supporting struts H4. The tube I09 and struts H4 are preferably formed of a heat resistant material such as Inconel, and may be painted with a ceramic paint. The above described fuel pump and drive therefor and the cooling of the nozzle parts by the exhaust from the air turbine are covered by my copending application Serial Number 780,864,

flled October 20, 1947.

The nozzle control G further includes a rod IIS connected with the spacer H2 and cross rod III of the throat member I08. This rod II5 extends forwardly through the tube I09 and is supported therein, by spaced bearings 1. As best shown in Figure 4, the rod II5 continues forwardly through the axial opening III; of the pump shaft 54, and the rotor of the pump carries a sealing means III for preventing the leakage of fluid around the rod. The rod H5 passes forwardy through the elbow SI and a packing gland II8 on the elbow to continue forwardly into a cylinder II9. A sleeve I on the rod II5 slidably enters the opening I2Iof the above described shaft 50, the shaft 50 having its end secured in an opening in the forward wall of the cylinder H3. A piston I22 is fixed on the sleeve I20 to operate in the cylinder 9, it being noted that the cylinder is of substantial diameter. The cylinder I I9 is suitably secured in the above described isand C by a series of bolts I23.

The propulsive nozzle control G further includes a pressure and bleed system for actuating and controlling the piston I 22, this mechanism being best illustrated in Figures 4 and 12. The forward end of the cylinder H3 is vented to the atmosphere by a vent pipe I24, which may pass rearwardly through the island C and then out through one of the struts 41. The system just 14 mentioned includes a pressure line I 25 leading from the entrance portion of the combustion chamber to the rear end of the cylinder III to de'.iver air under pressure to the cylinder. The line I25 may pass rearwardly through the island C, and then through one of the struts 41 to communicate with the main air passage of the engine at the upstream side of the fuel injecting strips 34. A pressure bleed line I26 extends from the rear end of the cylinder H8 to the atmosphere and may pass outwardly through the island C and one of the struts 41. The control system includes a relay valve I2'I interposed in the bleed line I25, the valve being actuated by instrumentalities sensitive to pressures at the entrance of the combustion chamber and at the throat of the propulsive nozzle I3.

The valve I21 has aclosure I20 secured to a rod or stem I23 and cooperating with a seat I30 to control flow through the bleed I26. An evacuated bellows I3I is secured to one end of the valve stem I23 and is contained in a closed chamber I32. A line I33 maintains the chamber I32 in communication with the throat of the supersonic propulsive nozzle I3. The line I33 may extend out through a strut 41 and continue along the exterior of the shell A to have its end open at the most restricted portion of the nozzle I3. The resiliency of the bellows I3I tends to move the closure I28 toward the seat I30, while the pressure conveyed from the nozzle throat by the line I33, acting upon the bellows, tends to move the closure away from the seat. A second evacuated bellows I34 is secured to the other end of the valve stem I29 and is subject to the pressure existing at the entrance to the combustion chamber. The bellows I34 is housed in a chamber I35, and a pipe or line I36 maintains the chamber in communication with the entrance portion of the combustion chamber. The line I36 extends through the island C and one'of the struts 41 to have its eLi open to the main air passage adjacent the upstream side of the vapor injecting system. In practice, the line I36 may communicate with the main air passage adjacent the open end of the line I25.

The control for the throat member I08 as just described, operates on the principle that the critical pressure in the throat of the nozzle I3 should be approximately .53 times the pressure at the entrance of the combustion chamber, assuming that the flow at the nozzle throat has a velocity of one Mach number. To obtain the proper action of the relay valve I21, the be'lows I3I and I34 are proportioned one to the other to preserve this ratio or relationship. For example. assuming the effective area of the evacuated bellows I3I, which is subjected to nozzle throat pressure, to be unity, the efiective area of the bellows I34, which is subjected to initial combustion chamber pressure, should be approximately .53. Gas pressures in the propulsive nozzle region result in a force tending to move the nozzle member I08 downstream. On the other hand, the pressures acting on the rear side of the piston I22, tend to move the throat member I00 upstream. This latter action is subject to or limited by the value of approximately .53 as impressed on the relay valve I21 and therefore upon the piston I22 by the proportioned bellows I 3I and I34.

Assuming that the throat member I08 is in a rearmost position where the throat of the nozzle I3 is restricted, the pressure at the forward end of the combustion chamber will build up, and

sure on the bellows I34 is lessened, and while the pressure on the bellows I3I may remain relatively high, the valve closure I28 is moved away from its seat I30. This allows an increased bleed of pressure from the cylinder I23 and the pressures acting on the throat member I08 move the member rearwardly to restrict the nozzle throat and compensate for the reduced initial combustion chamber pressure. The control G will usually remain in a condition of equilibrium to preserve the proper relationship between the combustion chamber pressure, and the spouting velocities and pressures at the nozzle to obtain maximum propulsive efiiciency at the various velocities of flight.

Although the operation of the several components of the power plant has been described in detail above, it is believed desirable to summarize the operation of the plant as a whole. It may be assumed that the engine is to be as- ,sociated with an airbornemissile or aircraft to form a propulsive means therefor and that the missile or craft carries the fuel supply and the controls for the starting system and fulcrum member I04. The missile or aircraft is brought up to or beyond the speed of sound, or a Mach number of one, by other propulsive means; for

example, by rocket power or turbo-jet propulsive devices. Itis at this speed, or'above the speed, that the ram jet unit becomes eflicient as a propulsive means. To start the engine. current is supplied to the glow plug 92, and fuel is supplied to either the main fuel line 60 or the starting jet 90, or both. Air flow through the annular passage I operates the air turbine I3, which in turn drives the pump 82 to supply fuel to the vaporizing means. The fuel flows through the tubes 11 and I8 to the struts 41 and bars 8|, and a small stream of the fuel is discharged against the glow plug 92 by the jet 9 I. The fuel is ignited at the glow plug 92 and as described, the flame progresses through the adjacent bar 8| to the several annular series of cup strips 84 to provide flames at the several cup strips. The fuel employed may be gasoline, coal oil, or other appropriate liquid fuel.

The supersonic ram inlet II and its shock wave reflecting needle B effects a compression of a large volume of air supplied to the combustion chamber. For example, at a speed equivalent to a Mach number of 1.7, the compression ratio will be approximately 3.6, and at a Mach number of 3.0 the compression ratio will exceed 17.0 to one.

During operation of the power plant the fuel is thoroughly vaporized during its passage through the tubes 11 and I8, and is efl'iciently consumed upon admission to the high pressure combustion chamber at the cup strips 84. It will be observed that the vaporizing means II'I8 in creases the efficiency of the plant by a regenerative action, and also protects, at least to some extent, the walls of the tubular shell A. The gases of combustion and the heated air are spouted from the nozzle I3 at a high velocity to produce a substantial forward thrust. As above described in connection with the detailed description of the fuel control F, the centrifugal pump 82 driven by the air turbine 13 and the associated by-pass control, maintain an emcient air-fuel ratio in the combustion chamber at the various speeds of operation, The movement of the needle B in the ram inlet II controls flow through the fuel by-pass 93 to automatically preserve the optimum air-fuel ratio. The means D which automatically adjusts the position of the needle B brings the needle into the position where it most effectively utilizes the highly efll- 'cient compressive action of the gentle shock waves 42 in the ram inlet II. This automatic adjustment of the needle B and the action of the shock waves 42 have already been described in detail. The fuel supply system in addition to being automatically controlled by movement of the needle B, is capable of adjustment or regulation by movement of the fulcrum member I04. As above noted, this member I04 may be shifted or set either manually, by an automatic mechanism, or by a remote control to obtain an increased or decreased thrust at will. Thus, al: though the power plant will operate automatically to obtain optimum efficiency at any speed, it may be controlled at will to regulate or vary its speed.

The control G automatically regulates the effective area of the propulsive nozzle I3 to produce an effective propulsion action at the various compression ratios and air-fuel ratios. It has already been described how the control G operates to maintain a substantially constant ratio of approximately one to .53 between the initial combustion chamber pressure and the critical nozzle throat pressure.

The power plant embodies a minimum number of working parts housed and arranged in such a manner that they do not constitute aerodynamic drag-producing projections. The working parts are within the shell A and the majority of such parts are within the needle and an island assembly B-C where they do not in any way obstruct the principal air passage. The ram jet unit of this invention is simple and inexpensive to manufacture, and therefore well adapted for use as an expendible power unit or propulsion device for guided missiles, etc.

Having described only a typical form of the invention, I do not wish to be limited to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art and/or fall within the scope of the following claims.

I claim:

1. A reactive propulsion engine comprising a tubular shell having an inlet ram at its forward end and a propulsive nozzle at its rear end, heat generating means in the shell in downstream relation to the inlet, an island in the inlet portion of the shell, a needle movable in the ram inlet and operable to reflect shock waves against the wall of the inlet to effect an eilicient compression of the air, the needle having a pointed forward end and having an external surface developed .to reflect said shock waves in convergence toward the wall of the ram inlet throughout the entire range of movement of the needle in the inlet, and means in the island for controlling the position of the needle.

2. A reactive propulsion engine comprising a tubular shell having an inlet ram at its forward end, and a propulsive nozzle at its rear end, heat 17 generating means in the shell in downstream relation to the inlet, a movable member for governing flow through the tubular shell, a pressure tap in the wall of the shell, and a servo mechanism responsive to the pressure in said tap for moving said member.

3. A reactive propulsion engine comprising a tubular shell having an inlet ram at its forward end, and a propulsive nozzle at its rear end, heat generating means in the shell in downstream relation to the inlet, an island in the inlet portion of the shell, a movable member for governing flow through the tubular shell, pressure taps communicating with the interior of the shell at given regions thereof, and a servo mechanism in the island sensitive to the pressures at said taps for governing the position of said member.

4. In a reactive propulsion engine, a tubular shell, an inlet ram at the forward end of the shell comprising an annular supersonic diffuser, a substantially central needle movable axially in the inlet and operable to reflect supersonic shock waves against the wall of the inlet, the needle being shaped to cause a convergence of the shock waves toward the wall of the inlet, and means sensitive to the location of substantial convergence of said shock waves for moving the needle axially of the inlet.

5. In a reactive propulsion engine, a tubular shell, an inlet ram at the forward end of the shell comprising an annular supersonic diffuser, a substantially central needle movable axially in the inlet and operable to reflect supersonic shock waves against the wall of the inlet, the needle being shaped to cause a convergence of the shock waves toward the wall of the inlet, a pressure tap in the wall of the inlet in the general zone of convergence of said shock waves, and servomotor means sensitive to pressure in said tap to move the needle axially so as to retain the region of convergence of the shock waves in the vicinity of said tap irrespective of an increase or decrease in the supersonic velocity of the engine.

6. In a reactive propulsion engine, a tubular shell, an inlet ram at the forward end of the shell comprising an annular supersonic diffuser, a substantially central needle movable axially in the inlet and operable to reflect convergent supersonic shock waves toward the wall of the inlet, and means for moving the needle axially in the inlet to maintain the region of convergence of the waves in the entrance portion of the inlet during operation of the engine at various Mach numbers, said means including a pressure tap in said entrance portion of the inlet, and a, motor mechanism sensitive to the pressure at said tap to cause forward movement of the needle when the pressure at the tap drops by reason of said shock waves moving to the rear of the tap upon an increase in the speed of the engine.

7. In a reactive propulsion engine, a tubular shell, an inlet ram at the forward end of the shell comprising an annular supersonic diffuser, a substantially central needle movable axially in the inlet and operable to reflect convergent supersonic shock waves toward the wall of the inlet, a pair of axially spaced pressure taps in the wall of the inlet adjacent the entrance thereof, the needle being hollow at its downstream side, a stationary island in the shell closing the downstream end of the movable needle, means for admitting pressure air into the needle to urge it forwardly, and valve means sensitive to the pressures in said taps for controlling the bleeding of pressure air from the needle to maintain the re- 18 gion of convergence of said shock waves between said taps at various supersonic speeds of the engine.

8. In a reactive propulsion engine, a tubular shell, an inlet ram at the forward end of the shell comprising an annular supersonic diffuser, a substantially central needle movable axially in theinlet and operable to reflect convergent supersonic shock waves toward the wall of the inlet, a pair of axially spaced pressure taps in the wall of the inlet adjacent the entrance thereof, the needle being hollow at its downstream side, a stationary island in the shell closing the downstream end of the movable needle, means for admitting pressureair from the difiuser into the needle to urge the needle forwardly, a valve for venting pressure air from the needle, and dia-' phragm means for controlling the valve and sensitive to the pressures at said taps to regulate the valve in a manner to maintain the region of convergence of said shock waves substantially between said taps at various supersonic velocities of the engine.

9. A reactive propulsion power plant comprising a tubular shell having a ram inlet at one end and a propulsive nozzle at the other end, heat generating means in the shell between its ends, a member movable in the inlet to control the same, means responsive to aerodynamic conditions in the ram inlet for moving the member and for controlling the heat generating means.

10. A reactive propulsion engine comprising a tubular shell having an inlet at its forward end and a propulsive nozzle at its rear end, heat generating means in the shell between said inlet and nozzle, a member movable in the inlet to control the same, means responsive to aerodynamic conditions in the inlet for moving the member, and a control for the heat generating means regulated by movement of the member.

'11. A reactive propulsion engine comprising a tubular shell having an inlet at its forward end and a propulsive nozzle at its rear end, heat generating meansin the shell between said inlet and nozzle, a member movable in response to variations in the supersonic velocity of the engine, and a control for said heat generating means regulated by movement of the member.

12. In a power plant of the reactive propulsive type, a ram inlet, a movable needle in the inlet having a forwardly convergent surface region for reflecting shock waves to the wall of the inlet when the power plant is operating at supersonic velocities, and means for moving the needle for wardly as the velocity increases so that said surface region reflects the shock waves toward the lip portion of the inlet at such increased velocities, said means including a servo mechanism for moving the needle, and a control for said mechanism sensitive to the pressure in the lip portion of the inlet.

13. A reactive propulsive unit comprising a tubular shell having an inlet ram at its forward end comprising an annular convergent-divergent difiuser, the shell having an intermediate combustion chamber and a propulsive nozzle at its rear end, a substantially central island in the diffuser, a needle shiftably telescoping over the island and presenting a forwardly convergent surface for reflecting shock waves toward the wall of the inlet when the unit is traveling at supersonic speeds, control means in the island for moving the needle forwardly upon an increase in velocity of the unit to cause said shock waves to be reflected into the forward portion of the inlet at 19 such increased speeds, means for injecting fuel into the combustion chamber, a control for the fuel injecting means governed by the position of the needle, and means for controlling the effective area of said nozzle.

14. A reactive propulsive unit comprising a tubular shell having an inlet ram at its forward end comprising an annular convergent-divergent diffuser, the shell having an intermediate combustion chamber and a propulsive nozzle at its rear end, a substantially central island in the diffuser, a needle shiftably telescoping over the island and presenting a forwardly convergent surface for refleeting shock waves toward the wall of the inlet when the unit is traveling at supersonic speeds, control means in the island for moving the needle forwardly upon an increase in velocity of the unit to cause said shock waves to be reflected into the forward portion of the inlet at such increased speeds, a fuel supply system for introducing fuel into the combustion chamber, a control for said system regulated by movement of the needle, and an overriding control for said system operable independently of the position of the needle.

15. A reactive propulsive unit comprising a tubular shell having an inlet ram at its forward end comprising an annular convergent-divergent diffuser, the shell having an intermediate combustion chamber and a propulsive nozzle at its rear end, a substantially central island in the diffuser, a needle shiftably telescoping over the island and presenting a forwardly convergent surface for reflecting shock waves toward the wall of the inlet when the unit is traveling at supersonic speeds, control means in the island for moving the needle forwardly upon an increase in velocity of the unit to cause said shock waves to be reflected into the forward portion of the inlet at such increased speeds, pump means for supplying fuel to the combustion chamber, a by-pass between the high and low pressure sides of the pump, a valve for controlling the by-pass to regulate the delivery of fuel to the combustion chamber, and an operative connection between the needle and valve whereby the position of the valve is determined .by the position of the needle.

16. A reactive propulsive unit comprising a tubular shell having an inlet ram at its forward end comprising an annular convergent-divergent diffuser, the shell having an intermediate combustion chamber and a propulsive nozzle at its rear end, a substantially central island in the diffuser, a needle shiftably telescoping over the island and presenting a forwardly convergent surface for reflecting shock waves toward the wall of the inlet when the unit is traveling at supersonic speeds, control means in the island for moving the needle forwardly upon an increase in velocity of the unit to cause said shock waves to be reflected into the forward portion of the inlet at such increased speeds, pump means for supplying fuel to the combustion chamber, a by-pass between the high and low pressure sides of the pump, a valve for controlling the by-pass to regulate the delivery of fuel to the combustion chamber, an operative connection between the needle and valve whereby the position of the valve is determined by the position of the needle, and a member adapted for manual or remote operation for regulating the valve independently of the position of the needle.

1'7. A reactive propulsion power plant comprising a tubular shell having a supersonic inlet ram at its forward end, a combustion chamber, and a propulsive nozzle at its rear end, a needle in 20 the inlet shaped to reflect supersonic shock waves to the wall of the inlet, means for supplying fuel to the combustion chamber, and means sensitive to the Mach number of the reflected shock waves for controlling the fuel supply means to vary the fuel delivery.

18. A reactive propulsion power plant comprising a tubular shell having a supersonic inlet ram at its forward end, a combustion chamber, and a propulsive nozzle at its rear end, a needle in the inlet shaped to reflect supersgnic shock waves to the wall of the .inlet, means supporting the needle for axial movement in the inlet, means responsive to the air speed of the power plant for shifting the needle to retain said shock waves-in the forward portion of the inlet at various supersonic speeds, means for supplying fuel to the combustion chamber, and means operated by movement of the needle for regulating the fuel supply means.

19. A reactive propulsion power plant comprising a tubular shell having a supersonic inlet ram at its forward end, a combustion chamber, and a propulsive nozzle at its rear end, a needle in the inlet shaped to reflect supersonic shock waves to the wall of the inlet, means supporting the needle for axial movement in the inlet, means responsive to the air speed of the power plant for shifting the needle to retain said shock waves in the forward portion of the inlet at various supersonic speeds, means for supplying fuel to the combustion chamber, and means operated by movement of the needle for regulating the fuel supply means including a constant flow fuel valve.

20. A reactive propulsion power plant comprising a tubular shell having a supersonic inlet ram at its forward end, a combustion chamber, and a propulsive nozzle at its rear end, a needle in the inlet shaped to reflect supersonic shock waves to the wall of the inlet, means supporting the needle for axial movement in the inlet, means responsive to the air speed of the power plant for shifting the needle to retain said shock waves in the forward portion of the inlet at various supersonic speeds, means for supplying fuel to the combustion chamber, a constant flow valve for regulating the fuel supply means and including a seat element, a member in the path of fuel flow having a Venturi passage cooperable with said seat element to restrict the flow, a piston on the Venturi member subjected to the action of said flow, the member being urged toward said element by the flow, and a connection between the needle and member.

21. A reactive propulsion power plant comprising a tubular shell having a supersonic inlet ram at its forward end, a combustion chamber, and a propulsive nozzle at its rear end, a needle in the inlet shaped to reflect supersonic shock waves to the wall of the inlet, means supporting the needle for axial movement in the inlet, means responsive to the air speed of the power plant for shifting the needle to retain the shock waves in the forward portion of the inlet at the various speeds of operation, a pump for supplying fuel to the combustion chamber, a by-pass between the high and low pressure ducts of the pump and having a discharge directed in the downstream direction in said low pressure duct of the pump, and a valve governing said by-pass and operated upon movement of the needle to regulate fuel delivery to the combustion chamber.

22. A reactive propulsion power plant comprising a tubular shell having a supersonic inlet ram at its forward end, a combustion chamber,

and a propulsive nozzle at its rear end,'a needle in the inlet Shaped to reflect supersonic shock waves to the wall of the inlet, means supporting the needle for axial movement in the inlet, means responsive to the air speed at the power plant for shifting the needle to retain the shock waves in the forward portion of the inlet at the various speeds of operation, a pump for supplying fuel to the combustion chamber, a by-pass between the high and low pressure ducts of the pump, a valve governing said by-pass to regulate the delivery of fuel to the combustion chamber, an operative connection between the needle and valve whereby the valve is operated by needle movement.

23. A reactive propulsion power plant comprising a tubular shell having a supersonic inlet ram at its forward end, a combustion chamber, and a propulsive nozzle at its rear end, a needle in the inlet shaped to reflect supersonic shock waves to the wall of the inlet, means supporting the needle for axial movement in the inlet, means responsive to the air speed at the power plant for shifting the needle to retain the shock waves in the forward portion of the inlet at the various speeds of operation, a pump for supplying fuel to the combustion chamber, a by-pass between the high and low pressure ducts of the pump, a valve governing said by-pass to regulate the delivery of fuel to the combustion chamber, an operative connection between the needle and valve whereby the valve is operated by needle movement, and an overriding control connected with said valve for increasing or decreasing the delivery of fuel to the combustion chamber irrespective of the needle position.

24. A reactive propulsion power plant comprising a tubular shell having a supersonic inlet ram at its forward end, a combustion chamber, and a propulsive no'zzle at its rear end, a needle at the inlet shaped to reflect supersonic shock waves to the wall of the inlet, means supporting the needle for axial movement in the inlet, means responsive to the air speed of the power plant for shifting the needle to retain said shock waves in the forward portion of the inlet at various supersonic speeds, means for supplying fuel to the combustionchamber, means responsive to movement of the needle for regulating the fuel supply means, and means for regulating the fuel supply means independently of the position of the needle.

25. In a reactive propulsion engine, a shell having a passage extending therethrough, an inlet ram at the forward end of the passage, a propulsive nozzle at the rear end of the passage, heat generating means in the passage, a member movable in the passage to control the flow of air therethrough, and means responsive to the pressure in the passage at the entrance of the heat generating means and to the pressure adjacent one end of the passage for moving the member.

26. In a reactive propulsion engine, a shell having a passage extending therethrough, one end of the passage being adapted to receive ram air, the other end of the passage being adapted to discharge a propulsive jet of air, heat generating means in the passage, a member movable in the passage to control the flow therein, and motor means for moving the member and responsive to pressures at longitudinally spaced portions of the passage.

27. In a reactive propulsion engine, a shell having a passage extending therethrough, one end of the passage being adapted to receive ram air,

the other end of the passage being adapted to discharge a propulsive jet of air, heat generating means in the passage, a member movable in the passage to control the flow therein, motor means for moving the member, and a control for determining the direction and extent of actuation of the motor means responsive to pressures in the passage at the entrance to the heat generating means and adjacent one end of the passage.

28. In a reactive propulsion engine, a shell having a passage extending therethrough, one end of the. passage being adapted to receive ram air, the other end of the passage being adapted to discharge a propulsive jet of air, heat generating means in the passage, a member movable in the passage to control the fiow therein, cylinder and piston means for moving the member, and control means responsive to pressures in the passage adjacent one end thereof and adjacent the entrance of the heat generating means for controlling the direction and extent of operation of said cylinder and piston means.

29. A reactive propulsive unit comprising a tubular shell having an inlet ram at its forward end comprising an annular convergent-divergent diffuser, the shell having an intermediate combustion chamber and a propulsive nozzle at its rear end, a substantially central island stationarily supported in the difiuser, a needle having a closed forward end and an open rear end which shiftably telescopes over the island so that the island constitutes a stationary plunger element and the needle constitutes a movable cylinder element, the needle presenting a forwardly convergent surface for reflecting shock waves toward the wall of the inlet when the unit is traveling at supersonic speeds, means for admitting fluid pressure into the needle to cause the same to move axiallyv of the inlet, and means for varying the pressure in the needle to control the position of the needle.

30. In a reactive propulsion engine, a tubular shell, two elements related for relative axial movement, one an inlet ram at the forward end of the shell, the other a needle arranged substantially centrally in the inlet and operable to reflect supersonic shock waves against the wall of the inlet, the needle presenting an external surface shaped to cause convergence of the shock waves toward the wall of the inlet, and servomotor means sensitive to the location of substantial convergence of said shock waves for moving said elements axially one with respect to the other.

NATHAN C. PRICE.

REFERENCES CITED The followingreferences are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 991,230 Noyes May 2, 1911 1,030,890 Johnson July 2, 1912 2,191,532 Kinzie et al Feb. 27, 1940 2,402,363 Bradbury June 18, 1946 FOREIGN PATENTS Number Country Date 47,412 France Jan. 28, 1937 (1st addition to French Patent No. 779,655)

50,033 France Aug. 1, 1939 (3rd addition to French Patent No. 779,655) 544,834 Germany Feb. 29, 1932

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