Abstract:
A turbineless jet engine includes no internal moving components, yet operates using a continuous combustion principle. The present engine is self-starting, i.e., no auxiliary source of pressurized airflow or unconventional fuels is required for its starting and operation. The present engine also requires no electrical energy after the combustion process has been initiated, with its fuel pump being operated by exhaust air from the engine. Starting injectors entrain airflow through the engine, with a portion of the inlet air being drawn through radially disposed, hollow pressure generators to the combustion section of the engine. Exhaust gas is recirculated to the front of the engine and passed through the pressure generators to entrain fresh air, to continue the cycle of operation. The present engine may be constructed in a variety of non-circular cross-sectional shapes, with or without inlet vane sweep, as desired, due to its lack of internal rotating components.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/466,790, filed May 1, 2003. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to reaction type internal combustion engines, and more specifically to a jet engine incorporating compressor, combustion, and compressor airflow entrainment means, but which incorporates no turbines or other moving parts, except for the fuel pump.  
           [0004]    2. Description of Related Art  
           [0005]    Internal combustion reaction type engines embodying various principles of jet engines have been known for a considerable period of time. Such engines of the prior art may be generally categorized as ram jet engines with no internal moving parts, pulse jet engines with oscillating inlet vanes, and turbojet engines with rotating compressor and turbine sections.  
           [0006]    The turbojet engine was developed relatively recently in the history of internal combustion engines, being used operationally only toward the end of World War II. This is primarily due to the extremely high temperatures and rotational speeds attained by the exhaust turbine(s) within the engine, with revolutions per minute (rpm) generally reaching a few tens of thousands of rpm. As a result, the metallurgy and manufacturing tolerances required for turbojet engines are quite demanding and costly. Moreover, “hot” section inspections of the combustion and exhaust turbine sections are relatively frequent, due to the extremely high temperatures attained in those areas of the engine and the high centrifugal forces encountered by the exhaust turbine as it rotates at tens of thousands of rpm. However, turbojets have proven to be more efficient than other forms of internal combustion reaction engines, and as a result are nearly universally used where jet propulsion is required.  
           [0007]    The desirability of a simpler form of jet engine is evident, after considering the limitations and expense of turbojet engines. A simpler form of jet engine is the pulsejet, which uses a series of oscillating vanes at the inlet end of the engine. Pulse jet engines have also been known for quite some time, with pulsejets being used as model aircraft jet engines and in some unpiloted aircraft. The pulse jet principle eliminates the rapidly rotating compressor and exhaust turbines, but the inlet vanes are prone to damage and the life span of the typical pulse jet is unlikely to exceed several hours at a maximum. Moreover, pulsejets are relatively inefficient and burn considerably more fuel than turbojets for an equivalent amount of thrust, and generally require an external source of pressurized air for starting.  
           [0008]    The ramjet, with its lack of moving parts, provides a solution to the problem of rapidly rotating or oscillating components. However, the ramjet has other limitations which do not exist with turbojets and pulsejets. The ramjet relies upon the internal pressure differential produced by the shock wave developed within the engine as air passes from supersonic to subsonic flow. This is achieved by carefully shaped and contoured venturis within the engine, which accelerate and decelerate the airflow as desired. The result is an engine which is capable of producing practicable amounts of thrust with no moving parts. However, ramjet engines cannot operate at zero ambient airflow velocity. They require some airflow velocity before the air flowing through the engine can reach the velocities required for the engine to function. As a result, ramjet engines require some other engine principle (usually a rocket, with unmanned aircraft) to provide the initial acceleration and velocity for operation.  
           [0009]    Consideration of the above engine principles and their corresponding limitations leads to the realization that an engine featuring the structural simplicity of the ramjet with its lack of moving parts, along with the relative efficiencies of the turbojet and its ability to operate at zero ambient airspeed, would be a most desirable development. The present turbineless jet engine responds to this need, by providing a reaction engine having a series of inlet vanes which emulate the compressor section of a conventional turbojet engine, with the inlet and compression section of the present turbineless engine feeding the compressed air to a combustion or burner section. Most of the heated exhaust air passes rearwardly through the engine to produce thrust, with a relatively small percentage passing back through the engine to the inlet and compressor section to entrain incoming airflow, thereby continuing the process.  
           [0010]    The only moving component required in the present turbineless engine, is an internal fuel pump turbine. The fuel pump turbine itself is operated by relatively high pressure exhaust gas from the combustion section of the engine once the engine is in operation, thereby eliminating the need for electrical and/or other power for the engine, except during the starting procedure.  
           [0011]    A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.  
           [0012]    U.S. Pat. No. 3,188,804 issued on Jun. 15, 1965 to John A. Melenric, titled “Turbo Supercharged Valveless Pulse Jet Engine,” describes an engine combination having a central turbojet engine which provides some compressed airflow to a series of valveless reaction engines disposed in an annular array about the turbojet engine. The valveless engines are described as utilizing an intermittent combustion principle (as opposed to the continuous combustion used in the present engine), but Melenric does not disclose any form of oscillating inlet control vanes for his annular engines. In any event, the use of a rotating turbine to drive a rotating compressor in the central turbojet engine, results in the Melenric engine more closely resembling a conventional turbojet engine than it does the present engine.  
           [0013]    U.S. Pat. No. 3,323,304 issued on Jun. 6, 1967 to Andres F. Llobet et al., titled “Apparatus For Producing High Temperature Gaseous Stream,” describes a turbineless engine which utilizes a series of concentric venturis to control the flow of gases through the engine. Heat exchanger tubes are also included within the engine. The Llobet et al. engine requires a pressurized source of gaseous fuel (e.g., propane, etc.), at least for starting. Llobet et al. also describe the use of a liquid fuel mixed with water, with the water being broken down into its chemical elements and recombined with other elements to produce heat and thrust. The structure of the Llobet et al. engine is annular, with no radially disposed louvered pressure generator airflow guides, as provided by the present turbineless engine. Moreover, Llobet et al. make no disclosure of any non-circular cross section for their turbineless engine.  
           [0014]    U.S. Pat. No. 3,517,510 issued on Jun. 30, 1970 to John A. Melenric, titled “Self-Starting Valveless Resonant Pulse-Jet Engine And Method,” describes an engine having a series of annular valveless engines which operate on a pulse principle. Exhaust is fed into a central collector, where most of the exhaust thrust is generated. The engine of the Melenric &#39;510 U.S. patent requires a pressurized gaseous fuel, with power being determined by the mix of gaseous vs. liquid fuel selected from the pressurized tank. The present engine is configured to operate using a more conventional fuel. No radially disposed pressure generator airflow guides are disclosed in the Melenric &#39;510 U.S. patent, as provided in the present turbineless jet engine invention. Moreover, no disclosure is made of an engine having other than a circular or annular configuration, in the Melenric &#39;510 patent.  
           [0015]    U.S. Pat. No. 3,750,400 issued to Thomas H. Sharpe on Aug. 7, 1973, titled “Self-Starting Air Flow Inducing Reaction Motor,” describes an engine having only a single moving mechanism, i.e., an inlet diffuser cone. The inlet cone translates forwardly and rearwardly depending upon dynamic pressure, and moves the attached fuel injector assembly correspondingly. The fuel injector system entrains airflow into a convergent-divergent inlet duct, with the fuel and air mixing and igniting in the combustion section downstream of the inlet. The engine of the Sharpe &#39;400 U.S. patent also requires a relatively high energy consuming preheating assembly for its operation, which feature is not required of the engine of the present invention. The engine of the Sharpe &#39;400 U.S. patent is more closely related to the ramjet principle of operation. No radially segmented, louvered pressure generator airflow guides are provided in the engine of the Sharpe &#39;400 U.S. patent.  
           [0016]    U.S. Pat. No. 3,800,529 issued on Apr. 2, 1974 to Thomas H. Sharpe, titled “Self-Starting Series Jet Engine With Throttling Assemblies,” is a continuation-in-part of the &#39;400 U.S. patent to the same inventor, discussed immediately above. FIGS. 6A and 6B are identical in the &#39;400 and &#39;529 U.S. patents, with other structure and operating principles being closely related between the two.  
           [0017]    U.S. Pat. No. 3,800,531 issued on Apr. 2, 1974 to Thomas H. Sharpe, titled “Self-Starting Annular Jet Engine With Plural Burner And Bypass Duct,” is another continuation-in-part of the &#39;400 U.S. patent to the same inventor, discussed further above. The Sharpe &#39;531 U.S. patent is primarily directed to the embodiment of FIGS. 8A and 8B of the &#39;400 U.S. patent. As in the other patents issued to the same inventor noted above, no radially segmented, louvered pressure generator airflow guides are disclosed in the &#39;531 U.S. patent.  
           [0018]    U.S. Pat. No. 3,841,090 issued on Oct. 15, 1974 to Thomas H. Sharpe, titled “Jet Engine Method,” is a divisional patent of the &#39;400 U.S. patent, discussed further above. The Sharpe &#39;090 U.S. patent is directed to the method of operation of the various embodiments or engine variations disclosed in the various patents to the same inventor, discussed above. The same points of distinction noted between those patents and the present invention, are seen to apply here as well.  
           [0019]    U.S. Pat. No. 4,085,585 issued on Apr. 25, 1978 to Thomas H. Sharpe, titled “Impaction/Induction Jet Engine,” describes a turbineless jet engine configuration which superficially resembles the engine of the present invention. However, a considerable number of differences exist between the engine of the earlier &#39;505 U.S. patent and the engine of the present invention by the same inventor. First, and most obviously, the engine of the &#39;505 U.S. patent includes a series of radially disposed exhaust capture vanes, which capture a portion of the exhaust and route it forward to entrain incoming airflow. The present engine does not require these exhaust capture vanes. Second, the engine of the &#39;505 U.S. patent incorporates relatively costly conventional burner cans in the combustion area. The present engine utilizes a concentric annular ring of combustion venturis, with each having an upstream starting fuel injector and a downstream run fuel injector. Third, the engine of the &#39;505 U.S. patent has a relatively small central exhaust gas return duct. The diameter of the exhaust gas return duct of the engine of the present invention is much larger proportionally to the cross sectional area of the engine, preferably on the order of about thirty percent of the engine diameter or width at the combustion section. Fourth, the present engine incorporates “flame holders” or deflectors and fuel deflectors to break up the fuel stream from the start fuel injectors. Finally, the engine of the present invention may incorporate rearwardly (or forwardly) swept louvered inlet pressure generators and different cross-sectional shapes, which features are not disclosed by the present inventor in any of his earlier issued patents, nor in any of the related art known to the present inventor.  
           [0020]    U.S. Pat. No. 4,118,929 issued on Oct. 10, 1978 to Thomas H. Sharpe, titled “Impaction Augmented Jet Engine,” is another continuation-in-part of the &#39;400 U.S. patent to the same inventor discussed further above, through a chain of abandoned continuation applications. The same points noted further above regarding the engines of the &#39;929 and &#39;400 U.S. patents to the same inventor, are seen to apply here as well.  
           [0021]    U.S. Pat. No. 4,267,694 issued on May 19, 1981 to Thomas H. Sharpe, titled “Staged Induction Engine,” describes a turbineless jet engine configuration which is essentially “inside-out” from the present engine configuration. The engine disclosed in the &#39;694 U.S. patent has a single, centrally located burner can which exhausts through a series of axially central, concentric ducts. These ducts deliver some percentage of the exhaust flow to a series of peripherally located ducts, which route the exhaust flow forward to a series of intake vanes at the front of the engine. The exhaust flow, along with the centrally located fuel injectors, entrains incoming air to the engine for operation. The intake vanes direct the exhaust flow and entrained intake air radially inwardly to the central burner can. The present engine utilizes a peripherally disposed combustion area, with a single, centrally located exhaust gas recirculation passage.  
           [0022]    U.S. Pat. No. 4,962,641 issued on Oct. 16, 1990 to John N. Ghougasian, titled “Pulse Jet Engine,” describes a vaneless pulsejet using a resonator chamber to fill and discharge a portion of the exhaust gas by oscillation. The pulsating exhaust gas pressure affects the incoming airflow, producing pressure pulses for a series of closely spaced combustion events. The Ghougasian engine apparently requires some form of compressed air for starting, as in conventional pulsejets, but unlike the present turbineless engine. The present engine is not a pulsejet, but rather is a continuous combustion engine with stable internal pressures and temperatures at any given location within the engine, for a given set of operating parameters.  
           [0023]    Finally, U.S. Pat. No. 5,189,875 issued on Mar. 2, 1993 to John A. Melenric, titled “Self Starting Valved Pulse Jet,” describes an engine configuration related to the engines of the &#39;804 and &#39;510 U.S. patents to the same inventor, discussed further above. As in those engines, the engine of the Melenric &#39;875 patent uses a pressurized fuel, e.g. propane or the like, and also utilizes a pulse valve system to control combustion after the initial startup phase, unlike the present turbineless engine.  
           [0024]    None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.  
         SUMMARY OF THE INVENTION  
         [0025]    The present invention comprises a turbineless jet engine having no internal moving parts whatsoever. The only moving component required for the operation of the present engine is contained within an externally mounted fuel pump, which may be operated by exhaust air from the engine once the engine has been started. No electrical energy is required to operate the present engine once it has been started and the fuel pump is being powered by exhaust air from the operating engine. However, other accessories (e.g., electrical generator, etc.) may be powered by exhaust air from the present engine, if, so desired.  
           [0026]    The present turbineless jet engine includes a series of radially disposed, louvered pressure generators at the inlet end thereof, which serve to channel a portion of the incoming airflow to a generally centrally located annular combustion area. Fuel is injected into this area, with the starting injectors oriented to entrain airflow through the engine during startup. As the air-fuel mixture is burned, it is exhausted to produce thrust, with a portion of the exhaust producing a backflow through a large diameter, axial return duct. The forward end of the return duct communicates with the louvered pressure generators to entrain airflow therethrough.  
           [0027]    The present engine includes various additional details as well, such as flame deflectors and novel fuel deflectors to break up the fuel stream from the start injectors. The present turbineless engine, with its lack of internal moving parts, is not limited to a circular cross section, as are conventional turbojet engines. The present disclosure also includes a series of engine configurations having different, non-circular cross sections, as well as a circular cross section configuration. Moreover, the louvered pressure generators at the inlet end of the engine may be swept at some angle other than normal to the central axis of the engine, if so desired, due to their lack of rotation and corresponding lack of centrifugal force acting upon these vanes.  
           [0028]    Accordingly, it is a principal object of the invention to provide a turbineless jet engine having no internal moving parts.  
           [0029]    It is another object of the invention to provide such a turbineless jet engine in which a portion of the exhaust flow is redirected forward through the center of the engine, and ducted to entrain fresh air into the engine and its combustion area.  
           [0030]    It is a further object of the invention to provide a jet engine having a fuel pump operated by exhaust flow from the engine, thereby obviating any requirement for electrical power for the engine once it has been started.  
           [0031]    Still another object of the invention is to provide a jet engine having a variety of different embodiments of different cross-sectional shapes, which may include sweep of the louvered pressure generator assembly to angles other than normal to the central axis of the engine.  
           [0032]    It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.  
           [0033]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0034]    [0034]FIG. 1 is a side elevation view in section of a turbineless jet engine according to the present invention, showing its general features.  
         [0035]    [0035]FIG. 2 is a detailed side elevation view in section of the forward, pressure generator section of the turbineless engine of FIG. 1, showing further details thereof.  
         [0036]    [0036]FIG. 3 is a detailed side elevation view in section of the central and rear sections of the turbineless engine of FIG. 1, showing further details thereof.  
         [0037]    [0037]FIG. 4 is a broken away detail perspective view of the combustion area inlets of the present engine, showing details thereof.  
         [0038]    [0038]FIG. 5 is a broken away detail perspective view of a portion of one inlet vane row or stage, showing details thereof.  
         [0039]    [0039]FIG. 6 is a detailed side elevation view in section of an alternate embodiment of the pressure generator section of the present engine, illustrating sweepback of the pressure generators.  
         [0040]    [0040]FIG. 7A is a front elevation view of a first alternative embodiment of the present turbineless jet engine invention, illustrating a generally square or rectangular cross-section.  
         [0041]    [0041]FIG. 7B is a front elevation view of a second alternative embodiment of the present turbineless jet engine invention, illustrating a rhomboid cross section.  
         [0042]    [0042]FIG. 7C is a front elevation view of a third alternative embodiment of the present turbineless jet engine invention, illustrating a generally triangular cross section.  
         [0043]    [0043]FIG. 7D is a front elevation view of a fourth alternative embodiment of the present turbineless jet engine invention, illustrating a generally elliptical cross section. 
     
    
       [0044]    Similar reference characters denote corresponding features consistently throughout the attached drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0045]    The present invention comprises various embodiments of a turbineless jet engine, i.e., a jet thrust or reaction engine having no internal moving parts. The present engine does not utilize an intermittent combustion operating principle, such as pulse jet engines, but uses a continuous combustion cycle more closely related to conventional turbojet engine operation, but without the high speed rotating compressor and turbine sections of such turbojet engines.  
         [0046]    [0046]FIG. 1 of the drawings provides an elevation view in section of the overall engine  10  of the present invention, with FIGS. 2 and 3 providing more detailed sectional elevation views of its forward and rearward portions. The present engine  10  includes a forwardly disposed air inlet section  12 , very roughly analogous to the compressor section of a conventional turbojet engine, but having no rotating compressor fans or other moving parts. The air inlet section  12  has a forward or airflow entrance end  14 , and an opposite rearward or airflow exit end  16  which communicates with an intermediate airflow passage area  18  between the air inlet section  12  and the generally centrally disposed fuel injector section  20 .  
         [0047]    The fuel injector section  20  includes a plurality of forwardly disposed starting injectors  22  and a similar plurality of rearwardly disposed run injectors  24 , with each set of injectors  22  and  24  disposed in an annular array with a like plurality of air entrainment venturis  26  disposed in an annular array between the start injectors  22  and run injectors  24 , forward of the rearward, annularly configured combustion and exhaust section  28 .  
         [0048]    The present engine  10  also includes a large diameter exhaust gas recirculation duct  30 , which extends along the centerline CL or longitudinal axis of the engine  10  from its rearward end  32  in the combustion and exhaust section  28  to its opposite forward end  34  in the forward portion  14  of the air inlet section  12  of the engine  10 . Other major components of the present engine  10 , i.e., the air inlet section  12 , fuel injection section  20 , and combustion and exhaust section  28 , are also preferably concentrically disposed about the longitudinal axis CL of the engine  10 , but it will be seen that as the present engine  10  contains no internal moving parts or components, that the present engine  10  lends itself to other than radially symmetrical configurations, if so desired. The rearward end  32  of the recirculation duct  30  is open to the ambient exhaust pressure and flow developed in the combustion section  28  of the engine  10 , with exhaust gases recirculating forwardly through the duct  30  to the forward air inlet portion  12  of the engine  10 , for purposes explained further below.  
         [0049]    [0049]FIG. 2 of the drawings provides a more detailed cross sectional view of the air inlet end  12  of the present turbineless engine  10 , with FIG. 5 providing a broken away perspective view of the individual louvered pressure generators  36  of the inlet portion  12  of the engine  10 . The inlet portion or end  12  of the engine  10  essentially comprises a number of pressure generators  36 , which extend radially from their inner ends  38  along the exhaust gas recirculation duct  30  to their opposite outer ends  40 . Preferably, a plurality of rows or stages of such pressure generators  36 , e.g., six stages, as illustrated in the example of FIGS. 1 and 2, are provided along the length of the air inlet section  12  in order to process a greater volume of incoming airflow by the pressure generators  36 . However, a greater or lesser number of rows or stages of such pressure generators  36  may be provided in any given configuration or embodiment of the present engine, as desired.  
         [0050]    The louvered pressure generators  36  are spaced apart radially with each pair of adjacent pressure generators  36  defining an air inlet passage  42  therebetween, as shown clearly in the FIG. 5 perspective view. Each of the pressure generators  36  includes an open front air inlet side  44 , which communicates with a rearward, radially disposed airflow passage  46  therein. A series of airflow guide louvers  48  are placed across each of the pressure generators  36 , with their outwardly turned trailing edges  50  serving to guide or channel airflow entering the pressure generators  36  radially outwardly along the interior of the airflow passage  46 . The outer ends  52  of the airflow passages  46  within the pressure generators  36  are open to an annular airflow passage  54 , which extends from the forward portion  14  to the rearward portion  16  of the air inlet section  12  of the engine  10 , where it channels the airflow collected from the louvered pressure generators  36  into the annular intermediate airflow passage  18 .  
         [0051]    The forward portion of the exhaust gas recirculation duct  30  includes a series of radially disposed exhaust gas passages  56  therethrough, with each of these exhaust gas passages  56  being aligned with the inboard end  58  of the airflow passages  46  of one of the louvered pressure generators  36 . After the engine  10  has started and is running, a portion of the engine exhaust flows forwardly into the open rearward end  32  of the exhaust recirculation duct  30 , continuing through the duct  30  to flow outwardly from the exhaust gas passages  56  in the forward portion of the duct  30 . The exhaust gas escaping from the duct  30  then passes through the airflow passages  46  of the pressure generators  36 , entraining ambient air into the pressure generators  36  from their open forward inlets  44 . The radially outwardly angled trailing edges  50  of the pressure generator louvers  48  assist in guiding the ambient airflow outwardly along the airflow passages  46 , where the exhaust and ambient air mix passes into the annular airflow passage  54  surrounding the inlet portion  12  of the engine  10  and continuing to the annular intermediate air passage area  18 . Ambient air is also drawn through the air passages  42  between the inlet guides  36 , by entrainment of air through the louvers  60  in the intermediate air passage area  18  between the intermediate annular airflow passage  18  and the interior airflow area  62  extending between and around the series of pressure generators  36  in the forward section  12  and continuing to the area between the exhaust recirculation duct  30  and the annular intermediate airflow passage  18 .  
         [0052]    Referring to FIGS. 3 and 4, the above described operation is initiated by means of the starting fuel injectors  22 , with one such starting injector  22  positioned immediately in front of each of the air entrainment venturis  26 , as noted further above. Each of the starting injectors  22  includes an outlet nozzle  64  which is aligned axially with the ambient airflow through its corresponding venturi  26 ; this is shown most clearly in FIG. 4 of the drawings. Fuel is injected into the passage immediately in front of each venturi  26 , thereby entraining airflow into and through the venturi  26 . Conventional igniters  66  are positioned rearwardly of the venturis  26  to ignite the air and fuel mixture for starting, and as desired during other conditions of operation (e.g., rain, etc.).  
         [0053]    Operation is continued after starting by means of a series of run fuel injectors  24  positioned rearwardly of each of the airflow entrainment venturis  26 , as noted further above. Once operation has stabilized after initializing the operation with the starting injectors  22  and producing the exhaust recirculation and air entrainment cycle described further above, the run injectors  24  are operated to supply the required fuel for operation.  
         [0054]    It is important that the starting injector nozzles  64  provide a stream of fuel aligned with the airflow through the entrainment venturis  26 , in order to entrain airflow through the venturis  26  and thus through the engine  10  for starting and initial operation. However, such a stream of fuel does not burn readily; it is important that the fuel stream be broken up into very small droplets and/or vaporized in the air, before ignition. Accordingly, a fuel deflector  68  is located immediately downstream of each of the starting injector nozzles  64 . The nozzles of the run injectors  24  are offset from the fuel deflectors  68 , and are configured to produce a fuel mist or spray for more efficient burning, as desired. In addition, a series of flame deflectors  70  is located between each fuel deflector  68  and corresponding igniter  66 , serving to preclude advance of the flame front forwardly in the engine  10  during operation.  
         [0055]    Fuel for engine operation is provided by one or more fuel pump assemblies  72 , with a single such fuel pump  72  being shown in FIGS. 1 and 3. The fuel pump  72  receives fuel from a fuel supply line  74  and distributes the fuel to either the start or run injectors  22  or  24  by corresponding fuel distribution lines  76  and/or  78 , as indicated in FIG. 3. Power for the fuel pump  72  is initially provided by a conventional electric motor  80  for starting. However, once the engine  10  has been started and sufficient exhaust pressure and volume is being produced, some of the exhaust may be routed to drive a fuel pump drive turbine  82  via a duct  84  extending from the exhaust gas recirculation duct  30  to the exhaust driven fuel pump drive turbine  82 . Once the engine  10  has been started, electrical power to the fuel pump drive motor  80  and igniters  66  may be terminated, with the engine  10  continuing to operate by means of the continuous combustion cycle of operation and the exhaust powered fuel pump drive turbine  82  without need of electrical power.  
         [0056]    The present turbineless jet engine  10  contains no internal moving parts or components whatsoever, as explained further above. The only moving parts associated with the present engine  10  in any of its embodiments, are the fuel pump assembly or assemblies  72  described above, and perhaps other conventional accessories such as a generator(s), alternator(s), etc., which may be powered by an exhaust driven turbine, similar to the fuel pump drive turbine  82 .  
         [0057]    As none of the internal components of the present engine  10  rotate or otherwise move during operation, they are not restricted to any given configuration or plane, as is the case with conventional turbojet engines. FIG. 6 illustrates a broken away elevation view in section of an alternative embodiment of the forward or air inlet section of the engine, designated as air inlet section  12   a . This air inlet section  12   a  embodiment functions similarly to the air inlet section  12  embodiment of FIGS. 1, 2, and  5 , but it will be noted that the louvered pressure generators  36   a  are swept back at an angle A 1  from normal to the centerline CL or longitudinal axis of the engine, i.e., the outer ends  40   a  of the pressure generators  36   a  are positioned somewhat rearwardly of their opposite inboard ends  58   a . It will be seen that this sweepback angle may be adjusted as desired for one or more rows or stages of the pressure generators  36   a , or varied between different pressure generators  36   a  in a given row or stage if so desired. Alternatively, a forward sweep angle A 2  may be provided for one or more pressure generators in one or more rows or stages, as desired.  
         [0058]    The lack of rotating or moving parts and components within the present engine  10  provides another advantage which is not possible with a conventional turbojet engine. Since there are no rotating components describing a circular path of rotation within the present engine, there is no requirement that the cross-sectional shape of the present engine be circular. FIGS. 7A through 7D illustrate front elevation views of a series of exemplary cross-sectional shapes for the present turbineless engine, with the engine  10   a  of FIG. 7A having a square or rectangular cross section, the engine  10   b  of FIG. 7B having a rhomboid cross section, the engine  10   c  of FIG. 7C having a generally triangular cross section, and the engine  10   d  of FIG. 7D having an elliptical cross section. While only the relatively air inlet section of each engine configuration  10   a  through  10   d  is illustrated in FIGS. 7A through 7D, it will be understood that the corresponding shape is applied to all sections of each engine  10   a  through  10   d , i.e., the air inlet section, fuel injection section, combustion section, and exhaust gas recirculation duct.  
         [0059]    Such non-circular engine cross sections may not provide the efficiency of an engine having a circular cross section, due to the increase in surface area relative to the internal volume of such non-circular shapes. However, such non-circular shapes may lend themselves to more efficient packaging in various installations, with the corresponding reduction in external surface area (“wetted area”) of the aircraft compensating for any losses of efficiency due to the non-circular cross-sectional shapes of the present engine. It will also be seen that such non-circular cross-sectional shapes also lend themselves well to adaptation within aircraft configured to have low radar reflectivity. The various non-circular cross sectional shapes illustrated in FIGS. 7A through 7D are exemplary, and it will be noted that a myriad of different non-circular cross sectional shapes may be achieved in a turbineless engine according to the present invention.  
         [0060]    In conclusion, the present turbineless jet engine, in its various embodiments, provides the potential to greatly reduce the manufacturing and operating costs in comparison to conventional turbojet engines. The lack of moving or rotating parts and components in the present turbineless engine serves to greatly reduce the manufacturing costs and labor involved in the highly precise production of compressor and turbine blades which must be carefully balanced and formed of costly materials due to the centrifugal forces applied and the high heat applied to the exhaust turbine blades. The present engine provides a number of additional advantages as well, such as its ability to operate without need for external electrical power once it has been started; the ability of the louvered pressure generators to be positioned at any practicable angle relative to the centerline of the engine, depending upon the anticipated operating parameters; and the wide range of non-circular cross-sectional shapes in which the present engine may be manufactured. The above features of the present turbineless engine will be seen to provide numerous advantages which are not possible to achieve with conventional turbojets or other types of reaction engines.  
         [0061]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.