US2311146A

US2311146A - Internal combustion engine for aircraft

Info

Publication number: US2311146A
Application number: US278415A
Authority: US
Inventors: Clarence H Wiegman
Original assignee: AVIATION CORP
Current assignee: AVIATION CORP
Priority date: 1939-06-10
Filing date: 1939-06-10
Publication date: 1943-02-16
Anticipated expiration: 1960-02-16

Description

Feb. 16, 1943. c. H. WlEGMA-N INTERNAL COMBUSTION ENGINE FOR AIRCRAFT Filed June 10, 1959 4 Sheets-Sheet 1 Feb.'16, 1943. c. H. WIEGMAN INTERNAL COMBUSTION ENGINE FOR AIRCRAFT 4 Sheets-Sheet 2 Filed June 10, 1939 fi 9 A J i1} w 1 1| 7 p G j a w 9 o 3 w w J a@ 5 a; a. I /7 6 "m2 M M5 5 Feb. 16, 1943. v c, wlEGMAN 2,311,146

' INTERNAL COMBUSTION ENGINE FOR AIRCRAFT Filed June 10, 1959 4 Sheet s-Shet 3 v razzaeffl l'sgmalz/ fl ir Feb. 16, 1943. c. H. WIEGMAN 2,311,146

INTERNAL COMBUSTION ENGINE FOR AIRCRAFT '4 Sheets-Sheet 4 Filed June 10, 1939 (Zane Patented Feb. 16, 1943' UNlTED S ATES PA T oFFIcs A Clarence]!- willi'amsmlhaalgnor,

bymesne ta,toTheAvhtion assignmen ration, New York, N. Y, a corporation of Deta- Application June 10,1939, Serial at. 210,415

8 Claims. (Cl. 123-56) The present invention relates generally to internal combustion engines. More particularlytheinvention relates to that type 'of internal combustion engine which is d primarily for mounting in the front portion of the fuselage of an airplane, and has the cylinders thereof dis.-'

cylinder type in which the various parts thereof are arranged in a novel manner and are so designed and constructed that they maybe readily dismantled in connection with maintenance, inspection or repair;

A further object of the invention is to provide an internal combustion engine of the type and character under consideration which includes simple and extremely ,emcient lubricating means for the rocker arms in the rocker boxes and is designed to provide maximum visibility for the pilot or operator of the airplane in which the engine is installed.

A still further object of the invention is to prodetail the construction and deal!! of ders, the cylinder heads and the mechanism for operating the valves;

Figure 5 is a vertical longitudinal section takenonthelinei-Joffigureiiandshowing the arrangement and design of the crank shaft and cam shaft of'the engine; v

Figure 6 is a vertical transverse section taken on the line H of Figure 5 and illustrating in detail the gearing whereby the cam shaft is drivenfromthecrankshaftoftheengine;

Figure-l is an inner face view of the casing at the rear end of the engine crank case for enclosing the cam shaft gearing;

Figure 8 is a perspective of the two castings which serve to form the crankcase and cylinders of the engine; t

Figure 9 is a perspective of the sump casting atthebcttomofthecrankcase; 4

Figure 10 is a perspective of one of the cylinder heads; 4

Figure 11 is an enlarged end view showing one or the rocker boxes at the outer ends of the cylinder heads without its cover and illustrating in detail the arrangement and design of the valve actuating rocker arms;

vide an internal combustion engine of the hori- I rental opposed cylinder type which is extremely light in weight and occupies but a small amount of space.

Other obiects of the invention and the various advantages and c of the present internal combustion engine will be apparent from :1 consideration of the following detailed descrip- The invention consists in the several novel fea-- tures which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawings which accompany and form a part of this specification or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is a plan of an internal combustion engine embodying the invention:

Figure 1" is a vertical longitudinal section on the line l -l of Figure 1; v

Figure 2 is a front view ofthe engine;

Figure 3 is a fragmentary horizontal section;

Figure 4 is a vertical section taken transverse ontheline'Hotr'iguresandillustiatingin Figure 12 is an inner face view of one of the covers forthe rocker boxes; .-Flgure13isanenlargedsectioncfone ofthe tappets for actuating the push rods of the engine; and

Figure 14 is a vertical section on the line Il-il of l'lgilre 13.

The internal combustion engine which is shown in the drawings constitutes the preferred embodiment of the invention. It is designed primarily to fonnthe propulsion medium for an airplane and comprises as the'main or essential parts thereof a pair of complemental crank case and cylinder forming castings ii, a set of cyllnderheads ",a crank shaft il, a set of pistonsil, a. cam shaft It, and a sump casting 2|.

The castings I! are complemental and, as

' shown in the drawings, are positioned in o p s relation. The inner parts of the castings l5 deflnetheenglnecrankcaseandareshapedto form a pair of opposed horizontally dongated substantiallyeparallel outer side walls II, a pair of horizontally aligned abutting front walls 22, a pair of horizontally aligned intermediate walls 23, and a pair of horizontally aligned abutting rearwalls 2|. {through-bolts ii are fixed in the inner faces of the side, intermediate and rear walls of one of the castings and these bolts extend through aligned holes in the front, interthe cylinto form a pair of opposed semi-cylindrical're-- cesses 2'! and these are longitudinally aligned with the recesses 26 in the front walls 22 and together define an opening for an inboard central bearing for the crank shaft. The upper inner.

portions of the rear wells 24 of the inner parts of the castings I5 are shaped to form a pair of complemental opposed semi-cylindrical recesses 28 and these are longitudinally aligned with the

recesses

26 and 21 and form a bearing opening for the rear end of the crank shaft ll. .The cam shaft 19 of the engine is disposed beneath and in parallel relation with the crank shaft and is driven by the latter, as hereinafter described. The inner lower portions of the front walls 22 are shaped to form a pair of opposed complemental semi-cylindrical recesses 29 and these constitute or form a bearing opening for the front end of the cam shaft. The inner lower portions of the intermediate walls 23 are shaped to form a pair of opposed complemental semi-cylindrical recesses 30 and these are aligned with the recesses 29 and form an opening for a central inboard bearing for the cam shaft. The inner lower portions of the rear walls 24'of the inner parts of the castings it are shaped to form a pair of opposed complemental semi-cylindrical recesses 3| and these are longitudinally aligned with the

recesses

28 and 30 and together form a cylindrical bearing opening for the rear end of the cam shaft. In addition to the front, intermediate and

rear walls

22, 28 and, the inner crank case forming parts of the castings I5 embody or inelude horizontally extending webs 32. These webs extend between the lower portions of the front, intermediate and rear walls and are joined to the lower portions of the side walls 2|. They.

serve to cross-connect the various walls constituting the inner crank case forming parts of the two castings l5 and operate to strengthen and lend rigidity to the castings I! as a whole. The inner ends of the webs 32 of one casting are preferably spaced from the inner ends of the webs of the other casting. At the lower corners of the side walls-2| four laterally extending lugs 23 v are provided. These embody vertically extending bolt holes therethrough and are adapted for use in mounting the engine in place. The bottom of the crank case whichis defined by the side, front, intermediate and end walls is closed or sealed by means of the sump casting 2|. The latter is disposed beneath the inner parts of the complemental castings l5 and forms a, reser-- voir or'tank for a column of .oil or other lubricant for the operating parts of the engine. The upper' margin of the casting embodies an integral horizontally extending flange l4 and this flange fits, against and is secured by vertical bolts to a correspondingly shaped bottom flange 35. The latter is formed integrally with and as ly'shaped flange 21 on the inner parts of the castings i5 andisremovablysecuredtosaid flange II by vertical bolts 38. 36 and the sump casting 24 assist the throughbolts in securing together and holding against separation the castings ll. When it is desired to separate the castings in connection with maintenance, repair or inspectionof the operating parts of the engine, it is only necessary to remove the cover plate 24 and the sump casting 22 and then release the through-bolts 2! by re- Inspection of or access to the crank shaft II and moving the'nuts on the threaded ends thereof.

the cam shaft II is obtained by removing the bolts 38 and raising the cover plate 2'.

- The outer parts of the two complemental castings II are formed integrally with the inner parts and are shaped to form four horizontally extending cylinders 39' as shown in Figures 1 and 8. There are two cylinders at each side of the engine, the cylinders at one side of the engine being arranged in opposed relation with those at the other side. The cylinders 20 are longitudinally bored from one end thereofto the other and communicate with the interior of the crank case byway of circular openings in thevside walls 2|. They slidably support pistons l8 and are separated by spaces 40. Annular fins 4| surround and are formed integrally with the cylinders 39. These fins are spaced apart laterally and constitute heat exchange or transfer means for use in air cooling of the cylinders. They sur-' round the central and outer end portions of the cylinders and are of substantially uniform diami eter. The adjacent portions of the fins on the central inner portions of'the cylinders are formed integrally with one another, as shown in Figures 1 and 3, and as a-result the castings I! are materially strengthened without any substantial increase in weight. The fins 4! around the outer ends of the cylinders are not cross-connected or attached and hence such outer ends of the cylinders are free or independent of one another and permitted to expand or contract each independently of the others. i

The cylinder heads l4 correspond in number to, and are associated respectively with the outer ends of, the cylinders 29. They are in the form of metal castings and consist of upper inner end parts 42, lower outer end parts 44, and intermediate parts 44 between the upper end portions of the outer end parts and the lower portions 'of the inner end parts. The inner end parts 42 are bolted or otherwise removably secured in sealed relation against the outer ends of the cylinders 30 and are outwardly bulged or dome-shaped. They define combustion chambers 45 at the out er ends of the cylinders and have annular laterally spaced integrally formed fins 4! for cooling purposes. The central portions of the upper inner end parts 42 of the cylinder heads have outwardly and upwardly inclined internally threaded holes 41. These hole'scommunicate with the combustion chambers 45 and serve as seats for the inner ends of a set of spark plugs 44. By reason of the location and angularity of the holes -4'l the spark plugs 44 are located for the most part outwards of the cylinders and hence do' not interfere with the vision of the pilot or operator The cover plate controlledbymeansofmushroomtypeexhaust valvesll. Th'epsrtsliofthecylinderheedslihavecoolingiinsliandarecored- .areprovidedwithinletsleevesli.

Theexhaustesilarepositimedins'ide bysiderelationwiththeinletpassageslland communicatewithandleaddownwlrdlyfrom' theexhaust ports I. Thelowerendsofthe exhaust es I! are provided with exhaustsleeves Il. As showninl'igure 3the inletesilinth'ecylinderheadsforthe fore or front cylinders are located in the rear portions of the intermediate parts 4| and the inlet es in the cylinder heads for the aft or rear cylinders are located in the front portions of the intermediate parts of the cylinder heads. AsshowninI'igureZLtheexhaustpassages "in the cylinder heads for the fore cylinders are catedinthefrontportionsoitheintermediate parts and the exhaust passages II in the'cylinder heads for the aft or rear cylinders are locatedintherearportionsoftheintermediate parts of the cylinder heads. The lower outer end parts 43 of the cylinder heads are positioned outwardly of, and project below the sleeves IO and- They are formed'integrally wlththe intermediateparts N and define rocker boxes U0. The latter have open outer ends and these are normally closed by means of covers ll. The

covers are removably secured in place by bolts ll and when removed provide access to the interior of the rockerboxes II; The valves ii for controlling the intake ports have outwardly extending stems which extend through and slide within sleeves 6| which project into the upper ends of the rocker boxes it, as shown in Figure 4.

' Compression springs 02 extend arotmd the outer projecting-ends of the stems of the valves II and serve to urge .the valves into seated relation with the inlet ports Is. Said springs I extend between and abut against washers it at the outer ends of the stems of the valves Ii andshoulders around the outer ends of the, sleeves ii. The

valves 52 for controlling the exhaust ports Ilare located inside by side relation with the valves II and embody rearwardly and downwardly extending stems which fit slidably in sleeves l in the upper portions of the intermediate parts 44 of the cylinder heads l6 and project into the upper ends of the rocker boxes 5.. Compression springs 51* extend around the outer projecting ends of the stems of the valves 5! and serve to urge such valves into closed or seated relation with the exhaust ports II.

The valves BI and ll for controlling the inlet and exhaust ports 4! and Ill respectively are uncylindrical recesses 29 in the inner lower portions of the front walls 22 of the inner parts of the castings ii. The intermediate inboard bearing 12 Thelowerendsofthe-mletpak flt'swithintheopeningwhichisdeilnedb'ythe semi-cylindrical recesses and the rearbearingllilts andissecln'ed-withintheopening whichisdeiinedbythesemi-cylmdricalrecesses 5 II. The tappets II, the push-rods i1, and the rockerarmsilservetoaetuateorunseattheintake valves 40. The tappets II are slidably mounted in horizontally extending, transversely disposedtuhulartsll,andareposil9 tively moved or slid outwards during rotation of I thecamshaft libylobe's'lionsaidshaft. The cuts ll are formed integrally with, and constitute parts of, the horizontally extending l5 intheformofenlargedheadsand these, asshown in Figure 13 bear against the lobes 15. The

push-rods i! are disposed in and extend loosely through shroud tubes ll which extend horizontally between thecrank case and the lower inner portions of the lower outer end parts 43 of the cylinder heads I and are positioned beneath'the cylinders 30. The inner ends of the tubes II flt within holes in the lower portions of the side walls II of the inner parts of the castings II and communicate with the outer ends of the tubular enlargements ll. The outer ends of the tubes 18 are seated in holes in the lower portions of the outer lower end parts 43 of the cylinder heads and are in commlmication with 0 the lower portions of the rocker boxes 58. The push-rods 81 are longer than the shroud tubes I! and have the inner ends thereof arranged in abutment with the outer ends of the tappets 65.

' The outer ends of the push-rods 61 project into cup-shaped enlargements at their outer extremities. The rocker arms 89 extend substantially vertically and are disposed in the rocker boxes II. The central portions of the rocker arms 69 40 are Journaled on horizontally extending stub shafts I8 and these shafts, as shown in Figure 11, are mounted in bearings II in the side portions of the outer lower-parts ll of the cylinder heads II. The upper ends of the rocker arms bear against the outer ends of the stems of the intake valve II and the lower ends of the arms embody adjusting screws which bear against the cup-shaped enlargements at the outer ends of the push rods 81. when the lobes 15 on the cam shaft strike against the inner ends of the tappets BI they force the tappets together with I the push-rods 81 outwards in the direction of the rocker boxes 58. Such movement on the part of the tappets and-push-rods operates so to swing the rocker arms 89 as to unseat the intake valves 5]. The tappets 66, the push-rods 68, and the rocker arms 10 are located or disposed in side by side relation with the tappets 65, the push-rods 61 and the rocker arms 69 and operate In response to rotation of the cam shaft l9 to unseat the exhaust valves 52. The tappets 6B are slidably mounted in vhorizontally extending transversely disposed enlargements 8i and have at the inner end thereof enlarged hardened heads which abut against'lobes 82 on the cam shaft IS. The enlargements M are positioned in parallel relation with the enlargements 14 and are formed integrally with and as parts of the webs 32. The

push-rods 88 are positioned in parallel relation 70 with the push-rods $1 and extend through and fit loosely within shroud tubes 83'. The latter underlie the cylinders .39 and extend between the lower portions of the side walls 22 and the inner lower portions of the outer lower end parts 43 webs". Theinner'endsofthetappetsiiare of the cylinder heads ii. The inner ends of the 1 tappets and the outer ends of said push-rods project intothe rocker boxes, as shown in Figure 2. The rocker arms I0 extend substantially vertically and are disposed in the rocker boxes. The central portions of the rocker arms I0 are mounted on the stub shafts l0 and the lower ends of said rocker arms abut against the outer ends of the push-rods 00. The upper ends of the rocker arms abut against the outer endsof the stems of the exhaust val es I2 and operate to unseat such valves when the tappets 00 and the pushrods 00 are shifted outwards in response to the action of the lobes 02 during drive or rotation of the cam shaft I0. p

' The crank shaft I1 is connected to drive the cam shaft I0 by way of a pair of gears 04 and u andis .ournaled in a front bearing as.

intermediate inboard bearing 01, and arear hearing 00. The front bearing 00 fits within the 3 opening which isdefined by the semi-cylindrical recesses in the upper inner portions of the front walls 22 of the inner parts of the castings l0 and the intermediate inboard bearing 01 nts within the opening which is defined by the semicylindrical recesses 21. The rear bearing 00 overlies the rear bearing II for the cam shaft I0 and fits within the opening which is defined by the semi-cylindrical recesses 20 in the rear walls 24., The central portion of the crank shaft embodies crank arms- 00 and these arms, as shown in Figure 3, are connected by connecting rods 00 to transversely extending wrist pins 0I' in the inner ends of the pistons I0. Successive explosions in the combustion chambers 40 at the outer ends of the cylinders operate as well understood in the art to move inwards the pistons andeffect rotation of the crank shaft. The front end of the crank shaft projects beyond the front bearing 00 and carries a hub 02 for a propeller (not shown). The gear 84 is mounted on the rear end of the crank shaft and, as shown in Figure 5, is disposed outwards or rearwardly of the rear walls 24 of the inner parts of the castings I5 and is in mesh with the gear 65. The latter is suitably mounted on, and fixed to, the rear end of the cam shaft I0 and is also disposed rearwards or outwardly of the rear walls 24. when the crank shaft is rotated as the result of reciprocation of the pistons, the gears 04 and 00 operate to rotate or drive the cam shaft I0. A plate-like casing 03 serves to cover the gears 04 and 00. This casing is bolted to the rear walls and serveswith the throughbolts 25, the cover plate 00, and the sump casting 20, releasably or removably to secure the castings It in opposed connected relation.

A magneto 04 for supplying current to the spark plugs 40 is mounted on the upper rear portion of the casing 03' by means of bolts or other connecting devices, and is arranged so that the armature shaft thereof is coaxially positioned with respect to the crank shaft II. The front end of the magneto armature shaft is provided with a tapered spindle "and this is keyed to the hub of the cam shaftdriving gear 04.

The engine is lubricated by means of an oil pump 00. This pump comprises a casing 01 and a pair of meshing gears -00 and 00 in the casing. The casing, as shown in Figure- 7., s

7 formed as an integral part of the platee casing 00 and is locatedat the lower portion of the latter. The gears 00 and 00 arerotatably mountedinthecasing 07. The gearjliskeyed to the rear extremity of the cam shaft Iland 5 operates during drive of such shaft to rotate the gear 00 and create suction in one side of the casing 01 and pressure in the other side of the casing. The suction side of the pump 00 is connected to receive oil from the bottom of the 0 sump casting 2.0 by way of a cored passage III. This passage is formed in the rear end wall of the sump casting and extends substantially vertically, as shown'in Figure 5. The outlet or pressure side of the pump 00 communicates with 5 a longitudinal passage III in the cam shaft I0 by way of a duct I02. when the pump is driven as the result of rotation of the cam shaft oil is drawn into the suction side of the pump casing 01 from the bottom of the sump casting 20 20 through or via the cored passage I00. After being placed under pressure the oil flows through the duct I02 into the'longitudinal passage III in the cam shaft. The cam shaft bearings II, I2 and I0 receive oil from the passage IN by means of cross-ports in the cam shaft. The

bearings 00, "and 00 for the crank shaft receive oil for lubricating purposes by way of upwardly extending oil passages I00 in the front, intermediate and rear walls of the complemental crank case and cylinder fonming'castings I5. These passages, as lead upwardly from the openings for the cam shaft bearings and receive oil from such bearings. In order to lubricate the tappets. pushrods and rocker arms constituting the valve actuating mechanism of the engine, the outer ends of the tubular enlargements I4 areprovided with upwardly facing holes I04 and the outer ends of the tubular enlargements 0| are 40 provided with downwardly facing holes I00, as

shown in Figure 14, when the engine is in operation oil in the crank case is splashed into the holes I04 and flows through the shroud tubes I0 into the lower portions of the rocker boxes 00. After lubricating the bearing forming portions of the rocker arms, the oil returns to the sump casting 20 by way of the shroud tubes 03 for the push-rods 00 and the downwardly facing largements 0 I.

formed by abutting webs which are formed integrally with the lower portions of the rocker box cover 00 and the lower outer end parts 40 of the cylinder heads I0. As shown in Figures 4 and 11, the dams I00 extend upwardly from the bottom of the rocker boxes and terminate at their upper ends adjacent to the rocker arm supporting shafts I0. As a result of the provision of the dams I00 the lubricant which is introduced into the rocker boxes flows around the lower ends of the rocker arms 60 and then over the dams and around the lower ends of the rocker arms I0 .and thence back to the sump casting 20 via the shroud tubes 00 and the holes I00. The upper endsof the rocker-arms are lubricated by oil vapor. The rocker boxes are air tight except for the passages aiforded by the shroud tubes. The shroud tubes 00 and the downwardly facing holes I05 constitute vents for the rocker boxes whereby pressure and ex- ;cess oil in the rocker boxes are vented into the sump casting 20. As the result of elimination of 7;; pressure in the rocker boxes by theaforemenshown in Figure M mm m I M the 3 2 we? p mani em m. I a

of the sim ie sunc'zl, es

m; an emerged ii [in the'uppet'pi Conduit, I, and hoflrbntai i meeaine the header 1.9m messhm ii zm'mr csen ne m W 8 the 8168M c a k eamec mmisie [wally are P d with sl v m-sm We a a s 9;

P u lliunderlie w M -P m frbmihe sump Mi 25 io ed fi af nvswi h; v a ends of the'fllbes are em e-b fl ibl flfltively rs ia d I' mwm j m tubes fi i t m 1 the f"? wi -v s r nku-ca ei ..da-. lioriz n ai,t muzhof th pipes Ill x e d-upw l k nk -bolts m 3 5 T l m wa s nd orizont throushe ts couplings em sle s. P Th tubes z udi -t r sh .iheeeermeus-mmmovabiy 111 the m 1 8 8nd fl P P a securinss e t o tosethei; assepar te y all the same i l mmas of this. rermedis p roz .lubrie nmdisposed beneathand me w ,m ltm i m 99 case" and ;having;-atop..;flange in'iabutmentiwith m! WY? 'qhe distme a the bottom marginal 901110118105 theidnnerziparts' the which travels tot e r combiwtim o! the two' castinmiwandgnonnected memovably em t n h ehe i efifix o t 'ji si ey thereto by vertical. holtm'is .:=sepai'-ate]y;;-formed. t u Y Q Q im w 4 cover plate forclosing theropenztopvomhezcrank mm disposed F- #QPfiWB 3" #38 93 4 case provided with'a marginalflangeein 'abutment M1 w im $91 3 9 i 9 .1 e with-theupper marginal JDOIHOHSQOQ said inner Ming Prim? P 5 8 6 i t i 909M 93 parts 10f the castings-ivandiconnectedcremovably cmmbersm de h q I thereto ,byimeans"o!yerticalgbolts,.ascrankflshait 'rnepreuuets of e'embu t bnemanatiiis twin extendinithrough'ithefimg iea'se mip r ll l the exhaust sleeves while fliejexhaus hiv lation; withthesidei-walisurand havingaitsefmnt are ope are dischar ed o dl means -endsjourna1ed2 ?in" .aa: eflfpni'sixbearingjbetween; the

or short substantially stxa isht exhaust 9 18 5 "F front-svaiis and itspreai's end dournalediima rear 'nese pipesai'esuita bly pQnnectedia-t ,their u per jbearinz betweemtheirean'walls;andzpistonsslid ends mine exhaust Sleeves; CB1 h vi sfih ablywmounted inihemylinderszand.connected 011- D 9 ULPOS -d -b athii e1cy nd rs n do. erativelytorthe cranksiiotathewcranh shaft; the exhaust pipes U6 dismissed inla dep n i internal-combustion engine'iinclud g manner from the intermediate parts 44 of the .pair of' complementalsshorizdnt'aily 'zextending cylin m v n i he se of pipes b uc castings disposed in side by side abuttme relae vision f pflq b heeim a el nwmc tionlnd havingiheiinneiv parts ;therebshaped h 81 6 j QR G ygh fihe 'fi F lg to'formanbpen'top andfopembcttoxnrciank case pper ends '0! the exhau t pipes dispos d-adj .andi 'comprisinz iateraiiy spacdfside wails and cent to he p r te e ds 0 the fuelv supply pairs-0f alimed and abutting fronbg intermediate 1 11 t 'sas uafu'e'l n ri 1 M and 'rearwallsg and having-the outenparts tliereof passages I! is subjected to heat 'fiom the *e'iz- 1 mg ra w am-gm e s gg g fi a l mbi s m 6o tiveiy' and"shaped;tc forim-oppositely exteiiding Tl e herein described engine because of-theateynnders with"then-31 1911ifendgvdommiinicating rangement and design 'of' thevarious parts there- -with:th k'1 interiori 11; z'poihtsibe'twe n or may be readily dismantled'andis extremelyeigfiidefront', mt tz -;w n mn.

ncient for its weight.- It occupies ibut a "comthrougii bdlts ex tendin'g lonitudinaliy parati'vely small 'space and provides-.imaximum ethmugh'said pairs izof waflgre pctivelyafida rv vision for the pilot 0t the airplane in whichthe ing removabiy wsecu're the-two eastin'gsjtdg'ether, engine ismounted; In addition to-;the foregoing a separatelyi'oimedsump' fof'iubricanfi disposd the present; engine ischaracteriz'ed byithe iact beneath and serving'tocldse the-bpen bottd" that the rocker arms areefliciently andeflectively the crank case and hav'ing fl'an'g at lubricated without venting the rockerboxesfto 7o the'upper part" there6tconn Bl atmospherethecylindei headsare so'dethe-botwm marginal' portionsdf signed that they areinterchahgeable By iiavot he two eestinesbyv r i in: the-cylindr -and 'ci-anizcase-forming parts formed-'cover plate tdr closing th oi 't'heengine'in th'e 'ioi'm of'twd' complemental the positioned" abiltn eestmge'tn'e"eneme'emboaie 'bu a mail nuu ber '6 n 'm m x .neciingrodstoihecnnksoftheerankshaft.

,3.Aninternaloomhlsflon cngineincluding a pair of cunplemental "horizontally extending castings disposed in side to amend abuttingrelafion and having the inner parts thereof shaped to form an open top and an open bottom crank oaseand laterally spaced side walls and pairs of aligned and abutting front and rear walls,- and having the outer parts thereof formed integrally with said inner parts respectively and shaped to form oppositely extending cylinders with their innerends in communication with the crankcase interior, horizontal through-bolts ex- 1 tending longitudinally through the front walls and horizontal through-bolts extending longitudina'lly through the rear walls for removably securing the two castings together,. a separately formed sump for lubricant disposed beneath and serving to close the open bottom of the crank case and removably secured by vertical bolts to the bottom portions of the inner parts of the two castings, a separately formed cover-plate for closing the open top of the crank case positioned in abutment with the upper portions of the inner parts of the castings and secured removably thereto by vertical bolts, vertically spaced crank and cam shafts extending horizontally through the crank case in parallel relation with the side walls and iournaled in bearings between the front w lls and bearings between the rear walls of the two castings, pistons slidably mounted in the cylinders and connected operatively to the cranks of the crank shaft, gearing for driving the cam shaft from the crank shaft disposed exteriorly of thejcrank case and positioned adjacent onepair of abutting walls, a casing for the gearing positioned in abutment with the last mentioned pair of walls, and bolts extending through the casing and'said lastmentioned walls and serving with said casing to assist the through-bolts, sump.

and cover plate in removably securing the castingstogether.

4. An internal combustion engine including a pair of complemental horizontally extending castings disposed in side by side and abutting relation and having the inner parts thereof shaped to form an open'top and open bottom crank case and comprising laterally spaced side walls, pairs of aligned and abutting front and rear walls and opposed horizontal webs projecting inwardly from the lower portions of the side walls and extending between and joined to the front and rear walls and having the outer parts thereof formed integrally with said inner parts respectively and shaped to form opposed cylinders with the inner ends thereof communicating with the crank case interior at points above said webs, horizontal through-bolts extending longitudinally through the front walls and horizontal through-bolts extending longitudinally through the rear walls for removably securing the two castings together, a separately formed sump for lubricant disposed beneath and servingtoclose the open bottom of the crank case and secured removably to the bottom portions of the inner comprising horizontally extending shaft actuated tappets slidablyimounted in the webs.

5; Aninternal combustion engine comprising anopenbottomcrankcasewithlatenllyspaced side walls, opposed'horinontally disposed cylinders connected to and extending outwardly from the side walls and having the inner ends thereof in communication with the crank case interior, individual cylinder heads connected to the outer ends of the cylinders respectively and embodying upper inner end parts forming combustion chambers for the cylinders, lower outer end parts forming rocker boxes, and intermediate parts extending between the inner and outer end parts and having side by side intake and exhaust pas-.

sages leading to the combustion chambers and extending through their bottom portions, a crank shaft extending through the crank case, pistons slidably mounted in the cylinders and operatively connected to thecranks of the crank shaft. a separately formed sump for lubricant disposed beneath and serving to close the open bottom of the crank case, secured removably in place, and having in the central portion thereof a an upstanding manifold with the lower end thereof leading through the sump bottom, a carburetor mounted beneath the sump bottom and having the fuel outlet thereof communicating with the lower end of the manifold, pipes for supplying gaseous fuel from the carburetor to the combustion chambers disposed beneath, and separate from, the cylinders and having the distion engine comprising a crank case with laterally spaced side walls and means forming an oil sump, opposed cylinders connected to and extending outwardly from the side walls and having the inner ends thereof in communication with the crank case interior, cylinder heads connected to the outer ends of the cylinders and shaped to form combustion chambers for the cylinders, intake and exhaust passages for said chambers and rocker boxes, a cam shaft Journaled in the crank case, valves for controlling the intake and exhaust passages, and cam shaft actuated mechanism for operating the valves including horizontal push rods between the crank case and rocker boxes and pivotally mounted rocker arms in said boxes, of horizontal shroud tubes extending loosely around the pushrods and extending between and communicating with the crank caseand the rocker boxes, and means whereby oil is permitted to flow by gravity from the crank case through certain of the shroud tubesinto the rocker boxes and from the 8. The combination with an internal combusrocker boxes back to the crank case via other shroud tubes.

7, The combination with an internal combustion engine comprising a crank case with laterally spaced side walls and means forming an oil sump at the bottom thereof, opposed cylinders connected to and extending outwardly from the side walls and having the inner ends thereof in communication with the crank case interior, cylinder heads connected to the outer ends of the cylinders and shaped to form combustion chambers for the cylinders, intake and exhaust passages for said chambers and rocker boxes, a cam shaft journaled in the crank case, valves in the cylinder heads for controlling the intake and exhaust passages, and cam shaft actuated mechanism for operating the valves including horizontal push-rods between the crank case and rocket boxes and substantially vertically extending centrally pivoted rocker arms in said boxes, of horizontal shroud-tubes extending loosely around the push rods and extending between and communicating with the lower portions of the crank case and therocker boxes, dams in the rocker boxes positioned between the rocker arms and extending from the bottom of the boxes to a point adjacent to the central portions of the rocker arm, and means whereby oil is permitted to flow from the crank case through certain of the shroud tubes into the rocker boxes for flow over the dams and from the rocker boxes back to the crank case via other shroud tubes.

tion engine comprising a pair or crank case forming castings secured together in abutting relation and embodying a pair or laterally spaced side walls and inaddition opposed horizontal webs extending inwardly irom the lower portions of the side walls and provided with tubular enlargements, opposed cylinders connected to and extending outwardly from the side walls, cylinder heads connected to the outer ends of the cylinders and'shaped to form combustion chambers for the cylinders, intake and exhaust passages for said chambers and rocker boxes, a cam shaft joumaled in the crank case, valves in the cylinder heads for controlling theintake and exhaust passages, and cam shaft actuated mechanism for operating the valves including tappets slidably mounted in said tubular enlargements, horizontal tappet actuated push-rods between the crank case and the rocker boxes, and pivotally mounted rocker arms in said boxes, of horizontal shroud tubes extending loosely around the push rods and extending between and communicating with the tubular enlargements and the rocker boxes, and means associated with said tubular enlargements forming upwardly and downwardly facing openings whereby oil in'the crank case is permitted to flow through certain of the shroud tubes into the rocker boxes and from the rocker boxes back to the crank case via other shroud tubes.

summon r'r. WIEGMAN.