US 3768255 A
An ejectable ram air inlet port cover is provided which comprises a plurality of segments arranged in close fitting side-by-side relation. The segments each have one dimension greater than a corresponding dimension of the inlet port to thereby bridge the port and the number of segments is so selected that the segments are smaller than the smallest dimension of the outlet nozzle from the combustion chamber.
Claims available in
Description (OCR text may contain errors)
United States Patent 1 Barnes, Jr. et al.
[ Oct. 30, 1973 INLET PORT COVERS FOR REACTION VEHICLE Inventors: Vernon M. Barnes, Jr.; Gerald M. Eisenlohr, both of Richmond, Va.
Assignee: Texaco, Inc., New York, NY.
Filed: Mar. 6, 1967 Appl. No.: 621,402
uLs. Cl. 60/245 Int. Cl. F02k 3/00 Field of Search 60/270, 244, 245,
, References Cited UNITED STATES PATENTS 5/1956 Winter et al 60/244 2,912,820 11/1959 Whitmore 60/225 3,086,359 4/1963 Davisi.... 60/244 FOREIGN PATENTS OR APPLICATIONS 590,177 7/1947 Great Britain 60/245 Primary Examiner-Samuel Feinberg Attorney-Stowe and Stowell  ABSTRACT An ejectable ram air inlet port cover is provided which comprises a plurality of segments arranged in close fitting side-by-side relation. The segments each have one dimension greater than a corresponding dimension of the inlet port to thereby bridge the port and the number of segments is so selected that the segments are smaller than the smallest dimension of the outlet nozzle from the combustion chamber.
4 Claims, 9 Drawing Figures PATENIED 0m 30' ms sum 1 BF 4 INVENTORS VERNON M. BARNESHJR. BYGERALD M. EISENLOHR ATTORNEYS PATENTEDHBTBO I973 3.76 8255 SHEET 2 0P4 mvmons VERNON M. BARNES, JR. GERALD M. EISENLOHR ATTORNEYS PATENTEDum 30 1975 SHEET U BF 4 INVENTOR S VERNON M. BARNES, JR. GERALD M. EISENLOHR BY 511 k 3 =VLi4 Z4 JQ5 ATTORNEYS INLET PORT COVERS FOR REACTION VEHICLE This invention relates to an improved ejectable air inlet port cover for a combined solid fuel type booster and liquid fuel ramjet engine.
The improved ejectable ram air inlet port covers have particular utility in an engine that is driven first by a solid rocket grain cast into the combustion chamber of the engine and then as a liquid fuel ramjet by opening of theiair inlets and initiating the flow of liquid fuel to the combustion chamber after the rocket grain has burned.
In general, solid rocket grain combustion and operation of such engines occurs at a substantially higher pressure than the pressure within the combustion chamber during ramjet operation and it is, therefore, necessary that the ram air inlet ports be covered and pressure sealed so that the pressure occurring in the combustion chamber during rocket operation is not lost through the air inlet ports.
It is a particular object of the present invention to provide cover means for the ram air inlets that are self ejectable by the relatively low pressure ram air available at rocket cut-off speeds and which will still satisfactorily provide a pressure seal during rocket operation.
It is an object of the invention to provide ramjet air inlet port covers that are readily ejectable upon rocket cut-off, that will not damage the combustion chamber surfaces during ejection and which will positively eject without causing blockage in the combustion chamber or the outlet nozzle therefrom.
Theseand other objects of the present invention are provided in a combination solid fuel rocket-liquid fuel ramjet, a combustion chamber, outlet nozzle meansat 1 engine;
FIG. 2 is an enlarged fragmentary partial sectionalview through one of the air inlets and a' portion of. the combustion chamber of the vehicle illustrated in FIG.
FIG. 3 is an enlarged partial transverse sectionalview through the vehicle illustrated in FIG. 1;
FIG. 4 is an enlarged fragmentary view of one of' the ram air inlet ports of the vehicle illustratedin FIGS. 1 a
FIG. 5 is a top plan view of the structures illustrated in FIG. 4;
FIG. 6 is a section on line 6-6 of FIG. 4;
FIG. 7 is a perspective view of one of the end segments comprising the port closure meansof the invention;
FIG. 8 is a perspective view similar to FIG. 7 of, for example, the center switch actuating segment. of the port closure means of the invention; and
FIG. 9 is a perspective view of one of the other segments of the port closure means of the invention.
Referring to the drawings and in particular to FIGS. 1 through 6, 10 generally designates an air traveling ve hicle having a main body 12, a nose portion 14 and a rear portion 16. The rear portion 116 houses a combustion chamber generally designated 18. The combustion chamber l8includes a front wall 20, cylindrical side wall 22, and a rearwardly directed outlet nozzle means 24. The combustion chamber is also provided with a plurality of ram air inlet ports generally designated 26. In the illustrated form of the invention four equally radially spaced inlet ports 26 are illustrated, however, the number and the positioning of said inlet ports may be varied without departing from the scope of the present invention.
Each of the ram air inlet ports 26 communicates with a ram air diffuser generallydesignated 28. As is known in the art, each inlet diffuser means 28 includes a forwardly directed air scoop 30 and a passage 32 for directing the incoming ram air to its respective inlet port 26: As more. clearly shown in FIG. 2 of the drawings, each of the ram air diffuser units has mounted therein a liquid fuel inlet nozzle means and igniter 34 of known construction whereby liquid fuel is directed into the incoming air streams for combustion in the combustion chamber 18.
The center portion '12 of the vehicle 10 houses a source of liquid fuel, and suitable means for transferring the fuel to the inlet nozzles 34 etc., in a conventionalmanner. The center section also houses a suitablesource of energy for driving the fuel pump and any additional auxiliary equipment such as guidance means for the vehicle.
The booster portion of the engine cycle is provided by. a conventional solid grain fuel 36 which is cast within the combustion chamber, and which solid grain is provided with its own igniter 38. In order to prevent loss of pressure duringthe burning of the solid grain 36 eachof the air inlet ports 26 is sealed by self ejectable port cover means 40. The port cover means 40 comprise a plurality of segments generally designated 42, 44;and.46. Segments 42, FIG. 7, comprise the end seg ments of the assembly; segment 44, FIG. 8, comprises one of thecenter most segments and the remainder of the segments are designated 46 and illustrated in FIG. f the drawings. In general, each of the segments has at; least one dimension greater than the corresponding dimension of the port to be closed and the other dimensions of each of the segments are selected such that the segments will freely eject through the combustion chamber nozzle during transition from the solid fuel booster. portion of the vehicles flight to the liquid fuel ramjet sustaining portion.
Eachof the end elements 42 of the segmented inlet port cover means 40 includes a quadrangular base portion 50. The length of the base portion 50 is such that flat ends 52overlap and engage the inner surface of the inlet port, as more clearly shown in FIGS. 2 and 6 of the drawings. Between the two end portions 52 is an upstanding angular bridge element 54. The bridge element 54 gives rigidity to. the segment and assists in centering the segment withinthe inlet port. On each of the end segments 42 the bridge element 54 terminates on one side in an upstanding rib 56, the lateral edge of which lies parallel to the corresponding edge of the port opening, as more clearly shown in FIG. 4 of the drawings.
Segment 44, shown in FIG. 8, includes a rectangular base portion 52' and an upstanding bridge element 54' which bridge is bored at 58 and 60 to receive retaining pins 62 and 64 and secure an upstanding insulating wafer or card 66 to the bridge. The card is adapted to slip between a pair of switch contact arms 68 carrying switch contact points 70 at their extended ends. The switch contact arms 68 are connected to an electrical switch 72 having leads 74 extending therefrom. The switch 72 is provided in the electrical circuitry which initiates the liquid fuel flares 34 and the pumps and the like for directing the liquid fuel to the fuel inlet nozzles forming a part of the flares or igniters 34. With the card 66 between the contacts 70, of the switch 72, actuation of the liquid fuel cycle of the engine is prevented. Preferably, each of the plural inlets 26 is provided with such a switch which are connected in series relationship whereby the liquid fuel cycle of operation is not initiated until all of the inlet port cover means have uncovered their respective ports.
The other of the segments making up the port closure means is, as hereinbefore described, designated 46 and is illustrated in FIG. 9. In FIG. 9 the closure segment 46 is illustrated as having a generally rectangular base portion 50 having a length substantially equal to the length of the quadrangular portion 50 of the segment 42 and 50 of the segment 44 to thereby provide end portions 52" which overlap the lateral edges of the inlet port and the upper surfaces of which bear against the inner surface of the combustion chamber. Each of the segments 46 also includes an upstanding bridge portion 54".
As illustrated in FIGS. 7, 8 and 9, each of the upstanding bridge portions 54, 54' and 54" are bored as at 80, 80' and 80" respectively. These bores are adapted to receive a temporary stringer rod 82 shown in broken lines in FIGS. 4 and 7. The temporary stringing rod 82 is employed in initially placing the plurality of segments 42, 44 and 46 in a port opening and after the port segments are in place and maintained in place as to be more fully described hereinafter the stringer rod 82 is clipped and removed from the assembly.
In operation of the inlet ports of the invention the plural segments 42, 46 and 48 are strung in the order shown in FIGS. 4 and upon the temporary stringer rod 82 and the strung segments are placed in each of the port openings 26 such that the overlapping edges 52, 52 and 52"0 engage the inner wall of the combustion chamber 18. Similarly, the edge 84 of each of the end segments 52 is placed in engagement with its respective side edge of its port 26. With the segments mounted in their side-by-side relationship, as shown in FIGS. 4 and 5 of the drawings, a rubber or the like liner orcoating 86 is placed or cast within the combustion chamber. The rubber coating is usually from about one thirty-second to about one-eighth of an inch thick and is applied to the entire interior of the combustion chamber case. This liner separates the propellant grain from the combustion case and is conventionally used in solid propellant grain rockets. The liner or rubber coating 86 serves both as a cushion between the solid grain 36 and the interior of the combustion chamber to provide for dimensional and thermal changes and as a thermal insulator during the combustion of the solid grain. This liner also serves as a pressure seal between the segments of the port cover means thereby preventing the outward thrust of pressure around or between the various segments during the short booster operation of the engine. After the rubber liner 86 is in place, the solid grain 36 is cast within the combustion chamber and the outlet nozzle 24 is closed by an ejectable and temporary barrier 88 which maintains the electrically ignited flare 38 within a bore or opening 90 in the solid grain. With all of these elements in place the temporary stringer rods 82 are clipped and removed from the segmented port cover means. The vehicle is then ready for flight.
Each of the segments of the port closure means are molded, cast or machined of a material which has sufficient strength and secondarily temperature capability to withstand the temperature and pressure existing within the combustion chamber during solid grain operation of the device. Preferably, the segments are made of a high strength to weight metal such as aluminum, steel, titanium or composition materials such as plastic, fiberglas or a composition such as epoxy resin and microballoons sandwiched between layers of glass fiber and epoxy resin.
EXAMPLE A combustion chamber was fabricated from 347 stainless steel and had a length of 52 inches and a diameter of 14% inches. The combustion chamber was provided with four ram air inlet ports each having a width of 5 inches and a front to rear depth of 2 inches. Each of the inlet ports was closed employing a pair of end segments and eight intermediate segments, one of which was provided with a switch actuating member. Each of the segments had an overall length of 2.5 inches and an overall height of 0.5 inch. The width of each of the intermediate segments was 0.5 inch while the width of the end segments was 0.620 inch to provide a .1 inch overlap along that edge of each of the end segments adjacent the edge of the inlet port opening. The quadrangular base of each of the segments was 0.210 inch thick. The segments were strung on a 1/16 inch aluminum rod and the assemblies were placed in the inlet port openings.
The inner surface of the combustion chamber was coated with a rubber liner about one-sixteenth inch thick and after the liner was in place a solid grain rocket fuel of conventional type was cast within the combustion chamber. The assembly was fitted with a solid grain igniter and end plug member, suitable instrumentation, and placed in a test cell. Upon ignition of the solid grain the maximum combustion chamber pressure of about 1,110 psig was reached at approximately 4 seconds. Transition from solid grain to liquid fuel occurred at approximately 4.75 seconds and the unburned liner and the ram air inlet cover segments ejected freely through the outlet nozzle of the rocket. Liquid fuel ramjet operation then proceeded at a combustion chamber pressure of about psig.
From the foregoing description of a preferred embodiment of the present invention it will be seen that the improved segmented self ejecting ramjet inlet port cover means fully accomplish the aims and objects of the present invention. While the invention has been shown and described in reference to an integral booster type ramjet, such inlet port covers could be used in any air-augmented system in which the supply of ram air is restricted to zero at first in the operation of the engine, but then is suddenly increased to a finite quantity to meet the needs of the combustion process. A ducted rocket or a solid fuel ramjet, both in combination with booster rockets, are specific examples of such further air-augmented reaction systems.
1. A liquid fuel ramjet having a solid fuel type integral booster comprising means forming a combustion chamber, an outlet nozzle means at the rear end of the combustion chamber, an air inlet port for the combustion chamber for directing ram air into the combustion chamber during liquid fuel ramjet operation, ejectable closure means for the inlet port closing said port during booster operation of the ramjet, said closure means comprising a plurality of port closing segments arranged in close fitting side-by-side relation and having one dimension greater than a corresponding dimension of the inlet port to thereby bridge the port and contact the interior surface of the combustion chamber, a solid fuel in the combustion chamber for use during booster operation of the ramjet, said solid fuel maintaining said port closing segments in port sealing relation until combustion of said solid fuel.
2. The invention defined in claim 1 wherein each of said segments includes a bridge portion projecting into said inlet port and providing rigidity for said segments.
3. The invention defined in claim 1 including a rubber liner for said combustion chamber the inner surface of which is in contact with the solid fuel and a portion of the outer surface of which is in contact with the inner surface of each of the closure segments, said liner forming with said plurality of port closing segments an ejectable gas seal for said inlet ports.
4. The invention defined in claim 1 including switch means associated with at least one of said segments.