US2609660A

US2609660A - Resonating pulse jet engine

Info

Publication number: US2609660A
Application number: US649882A
Authority: US
Inventors: William L Tenney; Charles B Marks
Original assignee: TENNEY
Current assignee: TENNEY
Priority date: 1946-02-25
Filing date: 1946-02-25
Publication date: 1952-09-09
Anticipated expiration: 1969-09-09

Description

Sept. 9, 1952 w. TENNEY EI'AL 2,609,660

RESONATING PULSE JET ENGINE Filed Feb. 25. 1946 2 SHEETS-SHEET 2 JVVEJVTGES' VV/LL/AM L. TENNEY CHARLES B. MARKS Patented Sept. 9, 1952 UNITED STATES PATENT OFFICE t I I 6 2,609,660

RESONATING PULSE JET ENGINE William Tenney, Crystal. Bay, Minn, and Charles B. Marks, Las Vegas, Nev. said Marks assignor to said Tenney Application February 25, 1946-,Serial No. 649,882

This invention relates topulse jet engines and particularly to'small size. pulse jet engines suitable for the propulsion of miniature ormodel airplanes, automobiles, boats and the like, and for furnishing a jet impulse for miniature or toy turbines or similar devices; whatever they might It. is an. object of the invention to provide a pulse jet engine, particularly of thevminiat'ure or model. type, which combines utmost simplicity andlow cost of'manufacturewith high efficiency ofv operation as well as lending itself. to incorporation intov miniature airplanes, cars, etc., as a structural part thereof. It is also: an object of the inventionto provideasmall pulse jet engine having a very high thrust forits weight and size, capable of being started and operated easily and safely, as well as being extremely simple to assemble and disassemble for servicing and replacement'of the valve which constitutes the only 12 Claims. (Cl. Bib-39.14)

moving part. It is a further object of: the inven- Theinvention is illustrated with reference to the drawings in whichv F-igure 1 is a side elevational view, partly in section, showing the external appearance of the jet propulsion unit andan air cooling shroudor partqof'the model in which the device is incorporated. The shroud: or model part is shown in section; s e r ,Figure-Z is a fragmentary cross sectional view of the. carburetor, valve and starting mechanism, combustion. chamber and a. fragment of the tail pipe assembly; 7 I v Figure 3 is a sectional view taken along the lines 3-.-3 of Figure-2; a

. Figure 4' is a fragmentary view, partly in, sec-' tion, showing one type of ignition plug mounting;

Figure 5 isafragmentary view, partly in. section, showing a modified form, of attachment between the. valve plategintake and combustion chamber, amodified form of fastening-for valve,

valve stop and fuel jet, and modified forms of sincejinoperationv the unit, moves in the direction a of. the. arrow 32. When the nosesection ,5, is

. v 2 Figure8 is a sectional view of the type shown in Figure 3, butshowing a modified form of valve plate, valve and valve support;

Figure 9 is a sectional view taken'atabout' the position of'section line. 9;--l0 of Figure 2, showing.

designated I!) which is attached to: anintegralor I fabricated converging section I! which is attached toan integral or fabricated tail pipe, generally designated i 2. The combustionchamber is also attached to a carburetor and valve plateunit generally designated M which may be covered by-a streamlined nose section 9.. 1

Referring to Figure 2 the carburetor and valve plate member 14 has acircular disk portion [5 which is faced so as topresent a smooth fiat surface at It. The carburetor and valveplate member Mhas an integral Venturi section II which presents a narrow throat at -8 and a belled out inletopening l9. 'The outer edge of the bell is providedwith a smooth surfacelil upon which theinturned flange 21 of the stream: lined nose piece 9 rests in frictional engagement. The disk portion [5 is provided with-a central shoulder 22 and is threaded in the forward direction at 24 and inthe rearward direction att25.

Threads 25 receive a threaded: ring 26ywhich' is set into the inside ofthe combustion chamber [,0

at its forward end. The ring- 26 may be fastened rear portion 30 of the streamlined nose section. 9 which may be integral with the ring 28 or, at-

tachedfb-y welding or othergsuitable' means. It

may be noted that the.;frontf-of the unit is the bell-shaped opening Iii-of the. Venturi section,

screwed onto the threads 24, the inturned; flange 2i rests against the surface, 20. of the venturi'lil v andthe. outer end of the streamlined-nosesection Q is thereby solidly supported. The tail pipe :sec-.

tion [2 may be made integraliwith the reducing section II. or t1l8=tWQ may be welded together, if 3 desired, and the reducing section it may bemade integral or welded. to the. tail pipe section -I 2'. The

making of the combustion chamber and tube section. In these figures the combustion chamber I0, reducing section H and tail piece 12 are made in two symmetrical halves (Figure 9) or in three symmetrical thirds (Figure 10) 'Thus, the

half sections

34 and 35 are provided with flanges 36 and 31 which extend outwardly throughout the length of the combustion chamber 10, the

reducing section II and the tube section 12. The 4 flanges may be fastened together by mean of a rolled lock jointseam or may be attached by gas welding or spot welding or continuous electric welding along the length of the unit. In Figure l0 the same'method of construction is used'except that the one-third sections 38, 39

and 4B are provided, each section being flanged at its edge so as toprovide a point of attachmentto the adjacent section. In both Figures 9 and 10 the flanges formed'by the juncture of 36 and 31 may serve as coolingfins, 'stiffeners, and additional mounting points.

In Figure 1 there is' illustrated an air shroud generally designated which may, if desired, be shaped as the fuselage of a model airplane, the body of a model car'or similar body part into which the unit is fabricated( The air shroud 45 is formed in the shape of a tube which provides an'a ir inlet at 46 and an air outlet at 48. If desired, shroud 45' may be terminated at 49 beyond the termination point 53 of the jet propulsion unit. Thus, thejet emanating from the tube 50 provides 'a' suction'eilect which induces a flow of cooling air-around the jet tube l2 introduced at inlet '46, even when the unit is not in forward motion. Where the assembly ill, I l and I2 is fabricated without the outwardly extending flanges 36 and 31 0f the type shown in Figures 9 and 10, the spacing of the shroud 45 may be provided. by means of thin inwardly projecting ribs 52 extending lengthwise of the unit at' the front end thereof and by similar projecting ribs 54 at the rearend thereof or by other suitable means. A plurality of these ribs, usually'th'ree or four, 'may be provided in both the front and back and thus adequately support the shroud in spaced relationship around the jet propulsion unit. The attachment of the shroud tothe unit may b'e'by means of pins or screws 55 which are preferably recessed into the metal of shroud 45 andpassed into the flange 22 of the valve plate M, or shroud attachment'may be made to an integral part ofa model airplane, car, etc. which replaces section 9, or by other suitable means. The shroud 45 may also be dispensed with altogether for purposes of economy and light weight, and attachment of accessories, wings, axles, etc. be made directly to sections H), U and I2 and also to threads 24, if desired. Where the combustion chamber and tail pipe includethe flanges 36 and 3'! of the'itype shown in Figures 9 and 10,-the spacing and supporting members 52' and54 maybe omitted since the ribs in themselves will provide the necessary spacing and support.

Referring to Figure 2 and 3, the valve plate 4 i4 is drilled or cast with a ring of inwardly and forwardly converging holes 56. The holes 56 extend at an angle to the center line of the unit and in converging towards each other, intersect and define a cone 58. The cone is, of course, supported at its rearward end by the web spacing 59 between the holes 55 in the valve face I 6. Ifdesired, the cone '58 may be finished so as to provide a smooth circular surface at its forward portion beyond the point of intersection of the several holes 56, or the flutes formed by the holes 55 may be permitted to remain. It is to be understood, of course, that the holes 55- may be cast, and in such instance the surface of cone 58 may be smooth or fluted as determined by the molds and cones of the casting. The valve plate I4 and cone 58 are drilled centrally at 62 and threaded to receive the cap screw 63 which serves to attach a valve backstop 64 and a valve 65. The valve 65 is shown out of scale in the drawings, but it is actually a thin, fiat,springy member. For this purpose high carbon blue .spring'steel serves adequately. The valve 65 is of gene'rallycircular shape and is apertured at the center 6'! sons. to permit the clamping cap screw 63 to pass therethrough. Outside of the aperture there is a small annular area 66 and beyond this the valve disk'is slotted or Cult as indicated at 68. The Width of the slot 68 is determined largely by the spacing'of the holes 55 in the valve plate, and since these are desirably set close together so as to provide a maximum port area, the slots 68 are accordingly usually very narrow. The radial slots 68 serve to form the valve disk into a plurality of petals indicated at 69. The petals are identical or nearly identical and are shaped off at their'outer ends as indicated'at 10. If desired, the outer ends may be rounded.

In practice we have found that blue tempered spring steel stock .006 inch in' thickness gives excellent results, although stock of somewhat thinner or thicker dimension may be used.

The valve backstop 64 has a convex forward surface which has a flat central area 72 having adiam'eter preferably slightly larger than the central-uncut area 66 of the valve. Therefore, when the valve backstop 54 is drawn tightly down against the valve plate with the valve 65 therebetween, each of the petals 69' is in effect separately clamped. The shape of the rear surface 74 of the valve backstop is of relatively'little importance and is illustrated in Figure 2 as slightly dished. As will presently appear in the descriptionof Figures 5, 6 and '7, the shape of this rear surface may be quite widely varied without disadvantageously affecting the operation of the device. The front curved surface 15 of the valve backstop 64- is, however, importantsin'ce it serves to support the valve at its maximum defiection. The front surface 15 of the valve stop is shaped so as 'to provide a limit and support for the valve at its maximumdefiection during operation and so as to provide support for the valve from the point of clamping of the valve radially outward'to the edge of the valve backstop; The valve may, if desired, extend somewhat beyond the valve backstop in order to allow air flow between the shaped ends 19 of the valve petals when the valve is at or near its point of maximum deflection. B shaping the'valve stop correctly, theform and eXtent'of valve d'efiection may be controlled so as marterially t o increase valve life and achieve even seating of'the valve on the valve plate surface'lfi.

isthreaded into-the. boss 19. on the tapered section: 1 If'desired, the valve plate-maybe recessed' as. shown at 80' in Figure 4, and the: spark plugiset in as indicated in this figure. Suitable aperturesaare provided in the'shroud 415 (or-in thenose section SWhen the spark plug is: located as in Figurec l'); soas to a'll'ow temporary at= tachment or a spark ignitionwirel Introduction of the;- fuel into the; venturi is. provided' by means of the'f'uelj et pipe 82 which is threaded at 83 so as to fit into the hole- 62' in cone 58.. The pipe 82? is preferably made from solid bar'materi'al and has a conical flange 84 shaped so asto fitup against the flat face 85 of the cone 58 and'to continue theconical surface tothe diameter of the rod 82. b The rod 82 isdrilled out at'S-l to the position of holes 88 which are cross: drilled-through the rod and serve as fuel metering'orifices and spray nozzles. The rod is provided with a ball-shaped protuberance 9i). Forwardl y of the ball 90 there is provid'ed'a gusset plate 92 to which an air injecting pipe 93 is attached so asto have a slight clearance from the ball 90 and terminates at about position 93." The pipe 93is used only iii-starting. At this time an air'hose 55 is attached. The air blast'through the tube 9'3 "scrubs over-the holes 88' in each side of the rodQthereby drawing-gasoline or other fuel from the fuel supplytank and ejectingjit from holes 88fin'a"spray; Theiblast of air'and fuel then continues through the holes 56 and lifts the=valves suffi'cientlyso as to p'erniit the combustible mixture to enter the combustion. cha n her "where iti s ig-nited by the S'park'pluglS. As combustion starts the valve pe'tals" 69 close against'the-seat l fi clue to their own resiliency and also-due to the force of the explosion. Theexpl'osionsets up a' blast through the tail pipe l2 and-the blast in traveling downthe tail pipe causes an injector suction wh-ichjdraws fresh air. through the venturi*ll.-'- The 'fiow'offairthrough the venturi; l'l islsufij'eientg to 'draw 'the fuel out o fjfthe jet' holesfiB "and provide a combustible ble mixture thenpasses.

mixture This combust through the valve ports 56 into combustion. chamber llhis ignited, and the eye repeats. with ex:-v

blast from the starting a aeoesco limits. of; the; combustion. chamber; and. the maxi mum lift is at or near the center of thercombusr tion chamber; hence,. onlyca'small effective valve port area may be opened. Further, these valves are made up of several pieces and 'areqfastened in several places; whereas with our valve construction only one fastening screw is requiredf In order to change our valve only "one screw need berem-ovedi Likewise; our valve 'stop ismadeup-of' only one pieceand fastened'jbyo'ne screw which" also serves to fasten the-valve Sinceth-is stop-is'merelya disk with a central hole a n d, a "convex surface on oneside, it in ay be made'with; great ease-flonf automaticscrew machines oro'n punch presses-i; The valve seating surface i'siiat and lies-in one.v plane only, lending'itself admirablyto low @0817 manufacture. Should theseatbecome inany way damaged, it can be, resurfaced by simply lapping it against'a piece or emeryicloth placedfoveri'ai flat surface." f Z ,7 p The fuel inlet jet is ofsimplest construction and is fastened in the same hole as the valve and stop clamping screw. f f The system of starting andfuel, supply of the present invention has outstanding advantages in safety, low cost and simplicity over other systems; ofwhich we have knowledge. In oursys: tem the, ffuel'tank' (not, illustrated is'fllocated be low the lowestport ofthe combustion chamber, and fuel is drawn through th'ef uelf1ine.'.(.82 of. Figures 1 and 2 I {8"ofFigure str; [96, of Figure 7) by the negative pressure induced. by theair. flow'through the'Venturii intake tube. ('I'Iof Fi uresl 'and'S) or in case. or starting; by the sud-1- tion effect. at the fuel nozzle, produced. by thel air ir tube. Thisfprev'ents flooding and dangerous operations thatwere com moninp'rior jetengines. In. one suchp'riorisystem'a pressurized fuel. tank was employedl In starting, .the'tank is pressurized from the starting air'source and when the, unitisinoperation plies: sure is suppli-ed ,,from;. a controlled. leak. inthe combustion chamber. Aside from beirfg complex l id'expensive to manufacture; this system intro k paratus of thistype. Inpur system. the angle. of. thejstarlti'iigair tub.

duc'es a. fire'hazard' which is objecti'on'aflol'e in eat in" relation to. thejet me as. is adjusted. at

so thata' 'ombustibleffuell-air. mixture 'isjisiil? plied" ove "wide'range oflai'r pressures} "mus. whenever air, 'under ,.pressure for starting is supiplied, throughftubie. 93. a combustible ,m'ixture is fed'to the. combustion chamber {it is impossible to supply an. "over-rich mixtures Withv the}. presf suri'ze'd tank system of the prior art-1o: .lwith.

treme'rapidity The'starting airtube s5 isthell' removed and the ignition wire likewise disconnected. Ignition is automatic after the' device is 'startdgi The device is then' freedj andjthe force of the -j etwhi h' comprises the propelling. forcefdrivesffthe evice e1- j rap1d1y., Particular attention is invited' to certain fea tures of construction and operation set-forth alcoves First, thevalve consists of butone piece, which ean -be made ona punch press. In spite of. the extreme simplicity ofthis valve, it is eiiicient infopening a large effective port area, since it' is clamped at. its center and lifts axially away' from its. center: the maximum li-ftlis at its outer periphcry,- and-henceja largeaefiective valve area' is opened... -In' othentypes of miniature pulsei jet engine valves of which We: have knowledge; the valves. areclamped at. or near the outer diametra-L- til i;

5y Ins-whichfthbugh ineiipensive have, pro n.-

gravity feed systems. over-rich incornbu'stible mixtures are often supplied, resulting in the collection of liquidfuel in the: combustion "chamber. When: acombustible mixture viszsubsequently sup? plied, the; liquid: fuel is blown out thetail pipe as a sheet of flame. With-our system, this action does not occurrf "have also xpernn'ented' with gravity fefdf dangerousbothjn starting an .11 neran n asillustratejdl althoughsthe u e sotnegj pe systems; in

r. .onstruction. maybe mbodiment-of theainve lustrative; e

portionally' within limits while maintaining good operation. I

Example-,1

The tail pipe is inches long, 1% inches diameter and approximately .020 inch thick. It is constructed of stainless steel. The converging section II is2 inches long having a minimum diameter the same as the tail pipe and a maximum diameter the same as the combustion chamber, i. .e. 2 /2 inches. Thecombustion chamber is 1% inches long and 2% inches in diameter. The valve plateventuri is approximately 2 2; inches long and is made of aluminum.- 'The valve plate is drilled with 16 holes, 1,4; inch in diameter drilled on a circ1e'l{-.% inches in diameter and converging into aiventuri having a throat diameter of 1 inch. Since the holes 56 are at an angle their intersection with the face I6 of thevalve plate is not quite circular. The distance from the outer edge of one hole to the outer edge of the diametrically opposite hole in the circle of valve holes is 2%; inches.- The valve 65 is made of blue tempered spring steel stock .006 inch thick and has an overall diameter of 2% inches. The slots between adjacent petals B9 of the valve are approximately inch at theirwidest part and extend to within .25. inch of the center. of the circle. The center hole for attachingithe valve is sufficient to receive ay 4 inch screw and the uncut annular area 66, Figure 3, is approximately .125 inch in width. The valve backstop was likewise drilled to receive a. A inch screw 03 and. has a flat area of contact against the valve of approximately .550 inch diameter. The outer diameter of the valve back; stop is 1.6 inches and the curvature thereof is such as to allow a valve lift of the tip of the valve of approximately inch,it being noted that the tip of thevalve extends substantially beyond the outer diameter of the valve backstop. The fuel orifices B8 are reamed with a #58 drill, and the starting air inlet pipe is .080 inch inside diameter. Themechanism so constructed produces in excess of four pounds staticthrust with norain air supplied. Starting, was easily accomplished by connecting an air supply hose temporarily to the starting air pipe 93. Approximately 50 pounds starting air pressure is needed for an easy start; although' starting may be accomplished at pressures as low as 35 pounds and lower. under favorable circumstances. The cornbustion isv clean and leaves practically no residue. ..The cycle frequency is 230 cycles per. second asdetermined byan oscillograph with vibration pick-up. The valve life is greatly in excess of that required for miniature applications, for example inmodel airplanes; a

" Example II" 3A combustion chamber 4 inches in diameter and having an overall length; including the tapered section II, of approximately 4 inches, tail pipe 2 inches in diameter and 30 inches long was used. The valve plate was made of magnesium' and drilled as described inExarnple-Lwithr-lo holesof is inch drilledto converge into a .venturi having an internal diameter of 1.33 inches. The diameter from the center of one valve port-to the center of the diametrically opposite valve port is"approximately '2.3 inches and the diameter from the outer edge of one port to the'outer edgef of the diametrically opposite port is approxi' mately2.75 inches. The valve was made of blue spring'steel stock .010 inch thick and had an over all diameter of 2.8 inches. The diameter of the uncutarea 60 (Figure 3) and the diameter of the flat area of contact of the valve backstop Gil-were both .75 inch. The valve lifted approximately .32 inch as measured from the surface of the valve plate to the tip of the valve spring when lifted to its maximum point. It may be noted in passing that the lines of contact marked in operation bythe valve against the valve backstop show clearly that inoperation the valve lifts until it lies entirely in contact with the curved surface of the valve backstop plate. In this instance the diameter of the valve backstop plate is approximately 2.4 inches. This unit developed in excess of seven pounds static thrust with no ram air.

. Referring to Figure 6 there is illustrated a modified form of the invention wherein the. principal variation from the device shown in Figures 1-5 is in the shape of the valve plate. In Figure 6 the valve plate generally designated I00 is provided with a flat central area IOI and a conical peripheral area I02 through which the entrance holes I03 extend. In this instance, as in the device shown in Figures 2 and 3, a plurality of holes I03 are drilled through the valve plate in a manner so as to converge into the Venturi section generally designated I05, and thus form a conical center I06 reaching into the throat of the Venturi. The valve has a flat central area I08 and this portion of the valve is held in contact with the flat central area IOI of the valve plate by means of the valve backstop generally designated IIO which likewise has a flat central area III and is held in place by means of the cap screw II 2. The valve is slottedto just beyond the bend I I3 so as to form individual outwardly protrudingpetalshaped blades I I5 which are orented so as to cover each of thevalve portsformed'bythe-holes I03. The petal-shaped blades} l5 are substantially flat, but may be preformed to the shape ofthe conical surface I02. It may be noted; however, that due to the smalldiameter of the holes I03 as compared with the diameter of the conical surface I02 through which they-protrude, it is relatively immaterial whether or not the valve blade is preformed since over the area of thevalve port hole a fiat blade serves to provide sufficiently tight valve closure. The valve backstop IIO has a curved surface H4 shaped so as to provide adequate support for the valve in its lifted position, as shownin dotted lines at H6. Fuel is introduced by means of the fuel inlet pipe II8 which is brazed or soldered to the plate I I9, the latter in turn being pinned or riveted to the entrance I20 of the Venturi. To the tube H8 there is attached a small gusset plate I22 which in turn serves to support the starting air inlet pipe I23.

For starting air supply tube I24 is attached and air under pressure is applied aspreviously described. This serves to-draw fuel from the openingf I25 of the pipe] I8 and to move the air fuel mixture through the holes I03 and thence against the petal-shaped valveblades I I5 which are lifted off their seats on the surface I02 and fuel-air mixture is introduced in the combustion chamber I30 where thest'arting combustion is initiated by the spark plug [3L a I 'In Figure fi thelvalve plate body I00 is pro vided with outwardly converging flange I32 having surfaces I33 and I34. The wall I3Eof the combustion chamber is flanged out at I31 and the rearsurface I38 of the cowling I40 is like-. wise flanged out so that the two lie incontact' with'the slanting-surfaces I33 andI 34. i A clamping ring I42, having corresponding s1anting'surfaces and provided with a screw device I43 at one pointin itsdiameter, is-tlien placed on and the screw"fl'stightened so as to provide "a hoop tension which accordingly draws t'he -cowli-n'g and the-combustion chamber-firmly into contact with the surfaces of the flange 132.

- The conical valve seat illustrated *in F i'gur'e 6 "is hfiiiterest in that "it o'lfe'rs a-more-e'ffici'ent valving arrangement than 'tl-nat illustratedin Figures 1 and 3, without additional complication or expensa exoept that involved in the manufao- 'tureoi the conical seat itself, and this needibe but very slight under mass roduction methods. With the conical-seat the diameter of the valve port circle -may *be increased in -rel'at'ion to the combustion chamber diameter witho'at reducing theai-r'ffidw, since-the direction of however the valve tips is more nearlyparallel' to the combustion chamber wall than with the flat seat arra-ngement. 'This ia'c't in itself permits of a greater area of holes [63 for a-given-comhustion chamber diameter. In addition, the shaping of the holes' -l 13 at-their interseotion with the conical surface Hi2, plus the directionof-air new in relation to valve, valve hac'kstop and combustion chamber, produces a higher eoefilcient of discharge per unit area or holes 1 63 than exists with the Bat seat arrangement. 7

-"'The conioal'seat cannot h'e resuraoed as sinip'ly'as *the flat seat, however. Provision of a hard seat surface 'by plating, anodizing or other suitable mear-1s eliminates any need for r'esur facing, but at additional cos't.

' In themodi'fication 'shOWn-inFig-ure' I the valve plate generally designated B is separated from the venme body 1-51 along thefline 153 for convenience fin manufacture. Thus, the plate F58 when removed can easily l1 die cast or maohi-nedand the Venturi body la-I is likew'ise more readily machined or cast. The valve plate is recessed into the threaded shoulder 15d of the Yenturi body-an'dis held in place by the inturned flange 55 'o'i thesscrew ring hi8which is set into the forward end of the combustion chamber. in this instance the Wall 1 56 of the *ooinbustion chamber is flanged but slightly so as to present ashoulder'at ltlagainst whih the'rin'g l es-seats and the protruding end or the wall "is turned. in at S 8 3 so that when the combustion chamber is drawn down'the inturned 'portion +63 of "the combustio-nchamberseats tightly against a eas ket at E5, the-gasket inturn being seatedagainst the shoulder 1 56 "The' combustion chamb'er 1 1:) is necked "downat' "M l and-joined to the tail pipe I '12 as previously desoribed.

*The valve plate l-Eflis provide'dinthis instance with a plurality "of cast in openings I75 which terminate normalto the flat surface 1-18 o'f the valve plate. Thus, for ashort distance, as indio'at'ed at -Pl9, the opening l lliis of the uniform shape shown-at H5 inFigureT ltlencegthe valve plate 15%) 1 may be -'re-faced without changing the position of the-valve ports. The 'ports H 5 *have the shape shown in Figure -8 and each o'fthe valvepetails [*8 I is shaped so-as to-provideasuboff :the :ports [15, "the now of ffuelair mixture through t-the port :is permitted not :only around the :tip orouterrendof "the valve, -;b ut also around each of its side edges, .and fiow {continues-cup around the petal-shaped backstop fingers 193 through the intervening spaces I92.

The valve baekstop "is in this instance held in place by the fuel sjet rod 4 Which-extends through the hole -I-98A and threaded at its inner end 't'o-receivenut ie-lwhich thus serves to clamp the valve backstop "39B andvalve 5 81 in place 'The outer end of the fuel jet rod i 51$ is drilled so as to provide a fuel passage and terminates in -fuel jet openings at cross bore 498. The fuel jet rod i416 serves to sujpport gusset plate 1299* which in turn serves to support the air in- -jeoting tube 2% for' providing thestarting-air supply. The cowling -291 is provided with angin- -ternally threaded ring 262 whicnis soldered or welded in place or otherwise" suitably 'fastened, the cowling being thus attached by screwing upon "the threads 203, as previously-doscrib'ed.

ln Figl-lre -2 or in-Figu-re 7' the jetpropulsion unit may be mounted b-y removing the cow-linge =(of Figure 2= I orcowli-n'g 294 of' Figure l) and by inserting the jet propulsiondevice through a mounting ringorapertureof the-propelled device (not illustrated) having a diameter sufii'cient to receive the threadedportion 2 3 or 2fl3. 'T-h'eco'wling is then screwed into place and thus serves to clamp tHe-deViceinpIa-ce on -thernodel or vehicle to which it is to he applied. -"This serves as a ready mounting tor the device. In Figure 6 the mounting bracket may readily be -a'ttac-hed to the hoop l iz either at the screw-portion M3 or elsewhere around the hoop.

In Figure 5 there is shown a modified-form of the invention wherein the valve backstop 28 6 is threaded so as to screw on the inwardly protruding threaded Send i StB of the fuel inlet rod [96. The surface of the valve backstop facing the combustion zone may be shaped as desired. In this modification also. the side iv'vall 290 --is flanged in at 201 over the threaded internal ring 202 which is fastened against turning by dimpling, crimping, spot welding, silver-solder, or the like. As the'combustion-ohamber and ring 2E2 are turned down-on threads 2113, the ring clamps the flange "281 firmly against flange 2134.

It will he noted that in Figures 5, 6 and'Tthe valve backstop dia'rnet'er is -n1ade e'qual to or greater than the valve disk diameter. 5 This is done inorder that, if desired, the valve step may protect the valve from the rnajor-hea't-and force of combustion and'act to protect and cool the {As many apparently Widelydiflerent embodiments-of this invention may bemade Without ideparting from the-spirit and scope thereof; it is to be understood that we do not limit ourselves to 4 the specific embodiments herein except as defined by the :appended'claims; 5

'1. In a resonant pulsejetfapparatus, ani'nlet portend valveunit adapted to-be secured at one end of a combustion .chamber said unit compriss m ansfformin a let opening, said passage havingja tapering "cross section defining a"Vent11 ri throat passage .jand then beingbranohedintoa plurality fjannu'larly arranged, openings terminatingfin Ports jon the facexof said unit, valve means including} seg mental flexible valve member Withthe segments thereof overlying said port ried by said unitdorsupporting said valvejmeans with the segmen-ts thereof exposed forfiexing to control the flow-of fuel and air through 'said port openings, and means located at said Venturi throat ffor supplyingiuel inim'eter ed relationinto the iinfiowing air in'said :passage;for zv'aporization thereof for combustion with resultant .;cooling of said unit and valve means.

passage having an air in eve s me ns car 2. In a resonant pulse jet apparatus, an inlet port and valve unit adapted to be secured at one end of a combustion chamber, said unit comprising means forming a passage having an air inlet opening, said passage having a portion of tapering cross section defining a centrally located throat and another portion extending outwardly defining a plurality of annularly arranged openings terminating in ports, valve means including a segmental flexible valve member with the segments thereof overlying said port openings, means carried by said unit for supporting said valve means with the segments thereof overlying said port openings, and means located at said throat for admitting fuel in metered relation into the inflowing air in said passage for vaporization thereof for combustion with resultant cooling of said unit and valve means. g

3. In a resonant pulse jet apparatus, an inlet port and valve unit adapted to be secured at one end of a combustion chamber, said unit comprising means forming a passage having an air inlet opening, said passage having a portion of tapering crosssection defining a centrally located throat and another portion extending outwardly defining a plurality of annularly arranged openings terminating in ports, valve means including a segmental flexible valve member with the segments thereof overlying said port openings, means carried by said unit for supporting said valve means with the segments thereof overlying said port openings, means located at said throat for admitting fuel in metered relation into the inflowing air in said passage for vaporization thereof for combustion with resultant cooling of said unit and valve means, and an auxiliary air supply tube for supplying starting air into said throat for producing an ignitible mixture of fuel and air in predetermined correlated proportion. I

4. In a resonant pulse jet apparatus, an inlet port and valve unit adapted to be secured at one end of a combustion chamber, said unit comprising means forming a passage having an air inlet opening, said passage having a portion of tapering cross section defining a centrally located throat and another portion extending outwardly defining a plurality of annularly arranged openings terminating in ports, valve means including a segmental flexible valve member with the segments thereof overlying said port openings, means carried by said unit for supporting said valve means with the segments thereof overlying said port openings, means located at said throat for admitting fuel in metered relation into the inflowing air in said passage for vaporization thereof for combustion with resultant cooling of said unit and valve means, and means for supporting said auxiliary air supply tube on said unit at an acute angle to the axi of the unit.

5. In a resonant pulse jet apparatus, an inlet port and valve unit adapted to be secured at one end of a combustion chamber, said unit comprising means forming a passage having an air inlet opening, said passage having a portion of tapering cross'section defining a centrally located throat and another portion extending outwardly defining a plurality of ,annularly arranged openings terminating in ports, valve means including a segmental flexible valve member with the segments thereof overlying said port openings, means carried by said unitfor supporting said valve means with the segments thereof overlying said port openings, and means located at said throat for admitting fuel in metered relation into the inflowing air in said passage for vaporization thereof for combustion with resultant cooling of said unit and valve means, said fuel supply means including a fuel supply tube having an outlet orifice within said Passage.

6. In a resonant pulse jet apparatus, an inlet port and valve unit adapted to be secured at one end of a combustion chamber, said unit comprising meansforming a passage having an air inlet opening, said passage having a portion of tapering cross section defining a centrally located throat and another portion extending outwardly defining a plurality of annularly arranged openings terminating in ports, valve means including a segmental flexible valve member with the see ments thereof overlying said port openingsmeans carried by said unit for supporting said valve means with the segments thereof overlying said port openings, mean located at said throat for admitting fuel in metered relation into the in flowing air in said passage for vaporization thereof for combustion with resultant cooling of said unit and valve means, a protuberance on said tube ahead of said outlet orifice, and an auxiliary air supply tube terminating adjacent said protuberance for supplying starting air into said throat.

7. In a resonant pulse jet apparatus, an inlet port and valve unit adapted to be secured at one end of, a combustion chamber, said unit comprising means forming a passage having an air inlet opening, said passage having a tapering cross section defining a centrally located throat, a generally cone-shaped member with its apex adjacent said throat and defining an annular portion having a plurality of annularly arranged openings terminating in ports on the face of said unit, valve means including a segmental flexible valve member with the segments thereof overlying said port openings, means carried by said unit for supporting said valve means with the segments thereof exposed for flexing to control the fiow of fuel and air through said port openings, and fuel supply means located at said throat and having an outlet orifice'for supplying fuel into the air stream traveling through said passage for vaporization of the fuel andconcurrent cooling of said passage and valve means.

8. In a jet apparatus, an inlet port and valve unit adapted to be supported at one end of a combustion chamber, said unit comprising an inlet member defining a fiow passage of generally Venturi shape, means for detachably mounting said member in position adjacent the end of said combustion chamber, means carried by said member for introducing fuel into the air stream substantially in the throat of said ventiu'i, means forming annularly arranged passages extending from said throat to a series of inlet ports for introduction of the mixture of fuel and air, a segmental valve member having its radially outer portions overlying said inlet ports, and a central support for removably mounting said valve member upon said inlet member providing for ready removal and replacement of said valve member upon removal of said unit from operative position.

9. In a jet apparatus, an inlet port and valve unit adapted to be supported at one end of a combustion chamber, said unit comprising an inlet member defining a flow passage of generaily Venturi shape, means for detachably mounting said member in position adjacent the end of said combustion chamber, means carried by said memher for introducing fuel into the air stream substantially in the throat of said Venturi, means forming annularly arranged passages extending from said throat to a series of inlet ports for introduction of the mixture of fuel and air, a generally cone-shaped member supported in said unit with its apex extending toward said throat defining annularly arranged passage means extending from said throat to a series of inlet ports for introduction of the mixture of fuel and air, a segmental valve member having its radially outer portions overlying said inlet ports, and a central support for removably mounting said valve member upon said inlet member providing for ready removal and replacement of said valve member upon removal of said unit from operative position.

10. In a jet apparatus, an inlet port and valve unit adapted to be supported at one end of a combustion chamber, said unit comprising an inlet member defining a flow passage of generally Venturi shape, means for detachably mounting said member in position adjacent the end of said combustion chamber, means carried by said member for introducing fuel into the air stream substantially in the throat of said venturi, means forming annularly arranged passages'extending from said throat to a series of inlet ports for introduction of the mixture of fuel and air, a generally cone-shaped member supported in said unit with its apex extending toward said throat defining annularly arranged passage means extending from said throat to a series of inlet ports for introduction of the mixture of fuel and air, a segmental valve member having its radially outer portions overlying said inlet ports, a central support for removably mounting said valve member upon said inlet member providing for ready removal and replacement of said valve member upon removal of said unit from operative position, and a valve backstop mounted in said coneshaped member for securing said valve member centrally to said unit and providing for ready removal therefrom.

11. In a jet apparatus, an inlet port and valve unit adapted to be supported at one end of a combustion chamber, said unit comprising an inlet member defining a flow passage of generally Venturi shape, means for detachably mounting said member in position adjacent the end of said combustion chamber, means carried by said member for introducing fuel into the air stream substantially in the throat of said venturi, means forming annularly arranged passages extending from said throat to a series of inlet ports for introduction of the mixture of fuel and air, a generally cone-shaped member supported in said unit with its apex extending toward said throat defining annularly arranged passage means extending from said throat to a series of inlet ports for introduction of the mixture of fuel and air, a segmental valve member having its radially outer portions overlying said inlet ports, a central support for removably mounting said valve member upon said inlet member providing for ready removal and replacement of said valve member upon removal of said unit from operative position, said fuel introducing means including a fuel supply tube having an outlet orifice, and means for supporting said tube upon said coneshaped member with said orifice in said throat of said passage.

12. In a jet apparatus, an inlet port and valve unit adapted to be supported at one end of a combustion chamber, said unit comprising an inlet member defining a flow passage of generally Venturi shape, means for detachably mounting said member in position adjacent the end of said combustion chamber, means carried by said member for introducing fuel into the air stream substantially in the throat of said venturi, means forming annularly arranged passages extending from said throat to a series of inlet ports for introduction of the mixture of fuel and air, a generally cone-shaped member supported in said unit with its apex extending toward said throat defining annularly arranged passage means extending from said throat to a series of inlet ports for in troduction of the mixture of fuel and air, a segmental valve member having its radially outer portions overlying said inlet ports, a central support for removably mounting said valve member upon said inlet member providing for ready removal and replacement of said valve member upon removal of said unit from operative position, said fuel introducing means including a fuel supply tube having an outlet orifice, means for supporting said tube upon said cone-shaped member with said orifice in said throat of said passage, an auxiliary air supply tube for discharging air for starting across said fuel orifice, and means for supporting said auxiliary air supply tube in predetermined accurate relation on said fuel supply tube.

WILLIAM L. TENNEY. CHARLES B. MARKS.

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

Talent.