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NATIONAL-.ADVISORY ,.COMMITTEE FOR AERONAUTICS

WAlrmm IUIIBOIU’ORIGINALLY ISSUED

February 1945 asAdvance Restricted Report E5B05

IMPROVING ENGINE COOLING WITH SPECIAL BAFFLES

By Arnold E. Biermann, Harvey A. Cookand Louis F. Held

Aircraft Engine Research LaboratoryCleveland, Ohio

NACA WARTIME RF FORTS are reprints of papers originally issued to provide rapid distribution ofadvance research results to am authorized ~r~up requiring them for the war effort. They were pre-viously held under a. security status but are now unclassified. Some of these reports were not tech-nically c’dited. All have been reproduced withcwt change in crder to expedite general distribution.

E-42

NATIONAL AWISURY cOMmT!mE

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ADVANGE RESTRICXEEO

~ qp#ii’iiiiii~i—--————-—H’(3RAEMXMUTICS

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REPORT ‘-

IMPR- ENGIN3 COOIJIG WITK SPEGIAL BAFFLES

By Arnold E. Blermann, Harvey A. Cook~aud Louis R’.Held

.

Tests were made to determine the a“fect of special baffles onthe temperatures and the cooling-air requirements d theWrl@t 1820 G200 and R-2600-3 cylinders. Nine baffle ccmblnatlonswere tested on a !4rIght 1820 G200 cylinder and two baffle cc#nbina-tions, on a front-row cyltider frm a Wright R-2600-8 engine. Onespecial baffle was tested on a front-row cyl~nder of anR-2600-8 multIcyllnder engine operating on a tcrque stand.

Some of the specIal baffles teeted reeulted In substantialreductions In cyilnder-bexreland rear cylinder-head temperatures.The ducts provided for conducting cold air to the high-temperatureregions wero very effective In improving the cooling of Internalareas that have good thermal connection with the external-coolingmeans, such as the combustion-chamberwalls. Teets with theWright R-2SO0-8 cyllnder showed that changes in the baffles werenot very at’fectivein reducing the temperature of sux’facesthattend to be thermally isolated frcm the external-coolingmeans, suchas the exhaust-valve crown or the s-k-plug center electrodes.

INTRODUCTION

The tests hereinCleveland during 1943cool- exhaust-valve

described were made at the NACA laboratory inas a result of dflffioultlesexperienced inand reEu”epark-plug reglcw of air-cooled

aircraft cyllndere during high-output crulslng operations. A spe-clfio obJect at this investigationwas to detemnine whether animprovement In cooling could be made by changing the cyllnderbaffling without causing an appreciable increase In total coollng-air flow. The foil- methode & improving oooling by means c#baffles were tested:

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2 ?iACAARR NO. E5B05

1. Increasing the coollng-alr mass flow across overheated areas

2. Reducing the coollng-air maes flow through the engine and thebaffle wall to a minimum consistent with the coollng required

3. shortening the cooling-air flow paths through long fin pas-sages by dividing the flow into several shorter paths

4. Conducting COOTLair to him-temperature re@O-~

Befoz% special b=”fles can be used as atanderd equipment, con-siderable testilngmust be dcme over a wide range af operating condi-tions because the specified maximum external temperatures will nolonger be criterims of safe internal temperatures when the newbat’flesare used. Baffle mcdtilcations that lower the temperature& the rear spark-plug boss.pro~ortionatelymore th.n the criticalInternal temperatures, euch as the spark-plug electrodes and theexhaust-valve cruwn, may reqMre a low mexlmum allowable boss tem-perature. Because d? the happreciable effect d external coollngon the temperature cf the exhaust-valve cl’own,as shwn in refer-ences 1 and 2, it ns believed advisable in these &escs to determinethe ef~ect of bs2-floztidlf:cationson the ccml”ingof tie mchaust-valve crown. Conseqlleiltly,%mpewturea of this reglm were meas-ured In tests of the most ~romlsing baffle combination.

APP.4RA’IWAND PROCEIU3E

Descr2ptlon of btifles. - The special baffles described In this—.report were fitted to either e Wright 1.820G200 cylinder or aWright R-260CM front-rcw cyltnder mounted an shgle-cylinder engines;nne sreclal baff16 wae also tested on a Wright R-2600-8 multlcyllnderengine. Each baffle tested is dmcribed end @ven an Identificationnumber. (See table 1.) The beff’lenumber followed by the letter “S”indicates the manufacturer’s standard baffle.

Table 2 lists the combinations of baffles tested and the reasonfor testing each conihhatlon. The identtiicationnumber designates ,the baffles makfng up the canbination. “The baffles listed intable 2 are ehuwn in ftgures 1 to 10.

Test Installations. --Single-cylindertests were conducted ontwo different Coo~eratlve Universal engines. The setups of the1820 and the 2600 cylinders, shown in fflgures11 aiid12, respectively,were similar In every respect except fur the cooling-air s~stms.Pewer was absorbed with electric dynamometers and fuel was suppliedby lnJection Into the intake pipes during the induction stroke.

HACA ARR NO ● ~5805 3

Coollng air was supplkd *O the 1820 cylinder by a varlable-speed cmntrfiugal blmar through a pipe & 8-lnoh diameter con-nbctbd”to a cbwlimg box -a--the engine..-The coollng+.r flgw wasmeasured with an ortfice installed at the entrance of the duct tothe oentrtiugal blower. Coollng-alr temperature was cautrolledby regulating the air temperature in the englna rocun.

Coollng air for the 2600 oyllnder was furnished by a centralalr system throu@ a duct of 16-Inch diameter leadlng to the cowllngbox, as shown In figure 12. Deflecting vanes were installed at thefrcmt d’ the 2600 cyllnder to simulate the ooollng effect of airmovements found In multIcyli.nderengines in flight. The poslticaof these vanes was ad~usted to gtve a temperature dlstributiontypical af that obtained when using the standard baffles In fl:ght.The vanes were fIxed In this posltfcm throu~out the tests. A con-trol valve and a heat exchanger were placed In the duct between theorifice and the duct to the cowllng box. The cooling-air tempera-ture was controlled by the flow af cold water through the heatexchanger.

Special baffles 46-48-49 were tested and ccxnparedwith thestandard baffles on cyllnder 2 M the front row of a Vr.-Wrfght R-2600-6 e~ine equipped with a torque nose and operat~on a torque stand. These tests were made with a flight propeller.Cooling air was drawn over the engine by a blower connected to theexit cf the en,glnecowllng.

Temperature measurements. - On the single-cylinder engines,c~llnder temperatures mre measured by thermocouples located assham in fi~ 13. The exhaust-valve crown and the spsrk-plugelectrode thermocouples (22, 23, and 24) were used only In some ofthe teats of baffles 41S-42S-43S and 46-48-49 on the single-cyllnder setup of the Wright R-26C0-8 front-row cylinder. Onlythe rear spark-plug-gasketand the rear middle-barrel temperatureswere measured in the [email protected].

Iron-mnstsntan thermocouples were used on the head and thebarrel. The thermocouples on the head were peened into holesdrilled to within approxlmatel.y1/8 inch aF the ccmbustim chamber.Thermocouples on the barrel were epot-welded to the outside sur-face of the barrel between fins. The thermocouple In the edmustrocker-am bolt was Installed on the center line of the bolt at theoonter UP the exhaust rcckor-arm bearing. A standard Army typerear spark-plug-gasketthermocouplewas used at the rear spark plug.

The method of installing a thermocouple In the exhaust-valvecrown was “stiilar to that reported In reference 1. A thermocouple “was fanned by welding a constantan tire at the end of a stal.hless-steel tube of 5/32-inch diameter that was inserted through a hole “

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drilled in the tip of the valve etti. The thermocouple was Insertedinto a hcle tillled to wlthln 1/16 inch of the outside surface ofthe crown and the valve was sealed with the original amount of sodium.

Chromel-alumel thermocouples were Installed In C34S sp=k” plugeIn holes drilled in the center electrode to wlthln 1/16 Inch of thecazbustlm.n-chamberend.

Tests. - Each baffle was tested at constant engine power, vszy~tig——the pressure drop across the cyllnder. The following engine ccndi-tions were ma-intainedmnst.ant during the tests:

1820 single- 2600 single- R-2600-8cylinder. cylinder multi-engine engine cylinder

1 a2 engine

Indicated horsepower . . . . . . .Englnespeed, rw . . . . . . . .Msnlfold pressure, ~nches

& mercury absolute . . . . . .Fuel-air ratio . . . . . . . . . .Inlet-air temperature, %’ . . . .Spark advance, both sparkplugs, degrees E.T.C. . . . . .

Ccznpresslonratio . . . . . . . .Cooltng-alr temperature, OF . . .Oil-in temperature, % . . . . . .AN-F-28 fuel, performancenumber . . . . . . . . . . . . .

662000

310.083250

206.76100180

130

782100

310.075160

206.9100180

130

1032100

380.10150

206.990180

130

bg75

2100

310..)75100

206.995145

130

%sts in which the temperature of the valve crown and the spsrk-plug center electrGde were measured in additlau to those of theokher areas.

%ultlcyllnder output in brake horsepower.

Ln both single-cylinder-enginesetups (figs. 11 and 12) thestatic press-we In the cowllng box ahead of the cylinder was deter-mined by a water mancmeter. The difference between this staticpressure in the cowling box and the engine-room pressure was usedas the Mffle cooling-air pressure drop Ap. 2ressure-drop measure-ments were corrected to stendard air density for the air in frontcf the cylinder by multiplying the measured Ap b~ a, the ratioof the density of the air ahw=d of the cylinder to the standardair density of 0.0765 pound per cubic foot. The pressure dropacross the multicyltider engine was measured by impact tubes infront of the cylinders end static tubes in the curl of the bd’flesat the rear of the cylinders.

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NACA

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ARR No. E5B05

Considerable osre&&flee to Insure.- *O deterllltie

5

was exerolsed In euocessive setups of thetistallatlon in the same looatiau. Teststhe.effect of small differences In baffle

Posltl&. “Ll&wlse, oare wus taken to i~ure that all the ooolingair flowed through %e paasages provided by the baffles and the -fins.

The performance cf eaoh baffle tested is presented In a plotshowing the varlaticm of cyllnder temperature minus cooling-alrtmnperature AT wfth baffle c!oollng-airpressure drop oAp. Acanp=lson & the performance of eaoh special baffle with respeotto the standard bdfle is made by plottlng the followlng rel.atlansagainst qAp:

Cylinder temperature- oooling-air tdmpef’ature(apeoIal baffle)Cyltider temperature-coollng-alr tamperatura (standard baf’fle)

X*OO

Coolq -air flow (specIal baffle)Coolhg-air flow (standsxd bdf le~ x 100

In the figures the foregoing relations are included under the ccmmonlegend

Performanoe ratio, special baffle x 100standard baffle

RESULTS AND DISCUSSION

Teets with the 1820 Cylinder

The baffle caubinatlons tested on the 1820 cyllnder are illus-trated In figure 14 and a ccxuparlson& ooollng-air flows for thesebafflea Is shown in f@ure 15.

EPfect of baffle mountl~. - The exaot looatlon and mountingof baffles on cyllnders is known to have an appreciable effect uponcyllnder cooling. h suns cases It la easll.ypossible to fit thebaffles in a number of different positions on the cyllnder, thuscausing a variation & the results obtained. In order to determinethe mounting etror involved m tests aE’this nature, the standardbaffles lS-2S-3S were ~amoved, reinstalled, and tested three tlmss.The scatter of the-data.m these three triale Is shown In fIgure 16.The lines falred through the points fm these three tests were usedin this investl~tion as representing the relation between cyllnder ,tempe~tures and cooling-air press- drop for the standard bafflesfor the 1820 oylinder.

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6 NACA ARR l!la. E5B05

The effect & incorrectly lccatlng the standard bed?fleson the1820 cylinder Is shown In figures 15, 17, and 16. The side baffles2S and .3Swere tivertaatl.y mounted too low on the cyllnder eel,which caused an increase in air-passage area below the lowest fheon the head. An improvement In cooling M more than 14 percentresulted frcm the change in baffle position. A part of this reduc-t~on in temperature can be attributed to a decreaee in the tempera-ture rise of the cooling air as the cooling-air flow is increased.

“ The 14-percent decrease in cylinder temperatures was acccqanledby an Increase In cooling-alr flow of frcun18 to 22 percent. Althoughan eng+.necowling can generally be redesigned @o as to mlnimlze theeffects of an Increase in fluw through the baffle wall on the powerrequired and the pressure dtiferance ava+.lable,it 2s evident that,for constant cowl-slot or cowl-flap outlet area, an incr6ase in theflow area under the baffl.eewill decrease the available pressure dif-ference across the t.e:fles. For this reason, the excellence of abaffle must be Jud&d not only in terms of the temperat~-e reductionsobtained for the pressure difference used but also in terms of thequantity d cooling air reqwlred.

Effects of raiGi~ baffles over uestrlcted fin passaRea. - The—.— .—resulGGf test~ cm bdfliZ-_yS are prer=;ted in fiawrss 19 and20. Btifle 10 was si.nlsr to the standard head baf-fle&cept thatit was fitted closer to the fin tins and the area over the exhaust-port fins was raised to ma~ntati constant flow area. The resultsshow slight pe.rcontegeticrecses and decreases In c~ltndsr te~era-tures. The alr-flov qusnt~t~ waa reducsd about 4 Fercent. meexhaust rocker-em bolt e~erienced the greatest reduction in A!17

(fig. 20) especially at lri cooling-air flows. From these resulisIt is a~pxrent Lhat the fins over the ex?muat-valvs sort are qui%eeffective in cocdlng the side of’the exhaust rocker box but haveonly a sl_lghtaffect on the temperature of the exhaust-valve guide,Test, results d baffles of this description are also presented inreference 3.

A more direct comparison of the value of increasing the bafflefin-tip clearence over restricted fin areas can bo obtained bystudying the test r~sults obtained wi’tbbaffles lS-6-7-8 and 1.S-6-7-9,which are shown In figures 15, 21, 22, 23, and 24. Baffle 8 wasfitted close to the fln tips on the side wall d the exhaust pmt.Thie f:nmd wall is inte~al with the valve-guide boss; tho vaive-guide temperature should therefore respond to any substantialimprovement in cooling of this srea. Baffle 9 was s:milsr to ljti-

fle 8 exceFt that the baffle was ralsud Gver the fins to obtainconstant flow area. Fur a cyllnder pressure drcp of 8 inches,

NACA ARR NO. E5805 7

baffle 9 lowered the exhaust-valve-guideixqerature 7° I’. Otheroylinder-head tempe~tures were less affected. The raised baffleoauaed only a alight Inoreaae in ooollng-alr flow.

Bafflea for intrcdncing cold air to hl~-temp erature areu. -Bafflea 6 and 7, which were designed to bring cold air frcxnthefront of the cyllnder and cause it to flow wer the hot area aroundthe rear spark plug, were tested in camblnation with baffles 9 end10, aa Illustrated In figure 5. The test results are * In flg-urea 15, 25, and 26 for bd’flea 10-6-7.9.‘ ThIa ocmblnatlau C&bafflea resulted In conalderably better coollng, eapeciall.yat therear & the cyllnder, than waa obtained with the standard [email protected] improvement was obtained at the expense of frcxu5- to 8-percentincreaae In alr fluw. “

The effect of aubatltutlng the standard head baffle ls forbaffle 10 in the foregohg combination Is shown by ccunparlngfig-ures 24 and 26. The alight decrease In flow with bafflea lS-6-7-9,which la somewhat contradictory to what was prevloualy found hccauparlngbtiflea ls and 10 In ccmblnathna 10-2S-3S and lS-2S-3S(fig. 20), ~ have been caused by a difference or a change InInterference of the air flows at the reex of the cylinder head.

Bsfflea lS-4-5-11-12were constructed to obtain better coolingof the cylinder barrel by dividing the flcrwon each aIde of the bar-rel in two pathe and by adding cold air at the aldee of the barrel,as shown In figure 6. The reaulta obtained =e ehown In flgurea 15,27, and 28. At a value of uAp at’6 Inches of water, the flow wasreduced about 14 percent and the barrel temperature were reducedfrm 5 to 1.0percent. Some Improvement In cylinder-head cooling waaeffected at the lower preaaure drops; otherwise the front tempera-tures increased, as might be expected from the decreaeed approachvelocitlea resulting fran the decreased weight flow & cooling air.

Another method of aohlevlng dlvlded flow around the barrel laillustrated In figure 7 (bafflea lS-4-5-13). In this dealgn, pertof the flow la brought to the rear of the barrel end then forward ashort distance tbrou@ the fins where It is discharged. The reaultaobtained with this baffle (fi@. 15, 29, and 30) Indicate a somewhatleaa favorable over-all performance than was obtained with bafflea1S-4-5-11-12; however, the middle and the top & the cylinder barrelat the rear experienced a reduction in temperature of about 30 per-cent as capered with 10 percent for bafflea lS-4-5-11-12. Furthermd3flcatians to baffle~ 11, 12, and 13 may provide additionalImprovementa h performenoe.

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withTests with S~~ cd-metal baffles. - Experiments WBre conducted=y~ti==f lea formed by spr@ng metal direct~y on the fin

tips, & Illuatnted In figure 8 (baffles 14-15). The sprayed baf-fles were tested in omblnatim with an air scoop over the head.Tfleread ts from this baffle ccunbinationare shown in figures 15,31, and 32. A 32-percent reduction in air flow was achiemd at a@p & 6 inches of water. Regions on the cylinder head, such asthe exhaust-vaive guide, the frent spark-plug bushing, the exhaustrocker-m bolt, and.the head between the valves whtch are mate-rially affected by baffle leakage and approach VS1OCitlea wereincreased In temperature. The barrel temperatures indicate thatbaffl~s spreyed on the barrel were Just as effective as the stand-ard baffles notwithstanding the lower coollng-air flow. The ductleading to the reer spark plug was very effective In reducing thetemperature at that point.

Tests with a Front-Row 2600 Cylinder

A number of beffles were tested & the 26C0 cylinder that havenot baen included in this report. The performance Of one of thebest baffle canbinations tested 46-48-49 ccn be ccauperedin fig-ures 33 to 36 with the standard baffles 4lS-42S-43S for this cylinder.The Increase in flow through this baffle ccanbinat~an was somsvhatexcessive, amounting to about 18 percent at a value of aAp of8 inches of water. Very substantial improvements were obtained, how-ever, In cooling the spark-Flug bushing and the rear cylinder barrel.Little change occurred in the temperature of the exhaust-valve guide.

Effect of special bef’fl~son exkmst-valve-crown and epark-plug-electrode temperatures. - A&dltional tests were conducted todetermine the effect of baffles 41S-42S-43S end 46-48-49 cm the tem-peratures of critical ueas, such as the exhaust-valve crown and thaspark-plug center electrode, which tend to be thermally Isolated frcmthe external cooling surface. These tests were conducted at higherpower than the previous tests. The results, which are presented infigures 37, 38, and 39, show very appreciable percentage reductionsin rsar spark-plug-bushing temperatures. The percentage reductionin the temperatures d the exhaust-valve crown and the spark-plugelectrodes, however, is relatively small. The relatim of UAp andcooling-air flow shown tn figure 35 ~ be applied to the foregoingdata inasmuch as power has little effect on this relatlcm.

Tests with the R-2600-8 Multicylinder Engine

Tests were made to ccqare the standard baffles and the specialbaffles 46-48-49 to determine whether the improvements observed insingle-cylinder tests could be realized with a multicylinder engine.

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After the performance of the standard bd’fles was determined, bti-., flea.46-49-49 were mounted cm cylinder 2 and the performanoe teata

were repeated. For ccmparlam, the petiomance of -the,-et.apdardbaffles and the special baffles on cylinder 2 are shown in fig-ure 40. The test results show Wprovemkent In coollng of the rearspark-plug gasket and the rear middle barrel.

That less Improvemmt In coollng Is shown In the multlcylindertests than In the single-oylindertests may be attributed Lxrgslyto the effects & air leaks that exiet In the multloyllnder-engjnebaffle wall and the fact that the speoial baffles were fitted toonly one oyllnder.

CONCLSJD~G REMARES

Internal cyllnder surfaces that have good thermal omnecticmwith the external-coolingmeans resnond to changes in external cool-ing. These Internal oyllader surfaces exe generally associated witha temperature level only slightly above the external temperatures.Such surfaces, which Include the combustion-chamberwalls and thevalv~ seats, are directly affect6d by baff18 modlficatlons.

hterrd cyliader surfaces that ten~ to be thermal~v isolat~dfrom the external-cooling means are predominately cooled by theincmdng charge. These surfaces, which Include the exhaust-valvecrown and the spark-plug electrodes, are idantlfied by their hl&operating temperatures. Such surfaces respond poorly to changesIn external coollng as caused by baffle modlfIcatIons.

Of the several methods tested for improving the cooling throu@special baffles, that of cnnduotlng cool air to the hi@-temperatureregions proves most effectlve. When the quantity of oooling airrequired Is considered, Improvements in cooling obtained by lnoreas-Ing the mass coollng-air flow me effeotive but relatively oostly Inair requirements.

Alrcreft Euglne Research Laboratory,Hatlonal Advisory Condttee for Aeronautics,

Clevelaud, Ohio.

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10 llACAARR NO. E5B05

1. Sanders, J. C., Wilsted, H. D., end Mnlcpihy,B. A.: OpsratlngTemperatures of a Sodium-Cooled Exhsust T“alveas Measured bya Thermocouple. NACA ARR NO. 3L06, 1945.

2. Cook, Hervey A.> Vendsman, Jack E., and Brown, Kenneth D.:EYfect of Several Methods of Increasing Knock-Li.nitsdPoweron Cylinder Temperatures. NACAARR No. E4115, 1944.

3. Scheyj Oscar W., Rollin, Vern G., and Buckner, lZowardA., Jr.:Comparative Coollng of Cyllnders of Nonunlfo?.mFln Width withTQjht-Flttlng Bd?flee and with Ba?Yles that Provide ConstantFlow-Path Areas. NACAARR No. E4D21, 1944.

NACA ARR HO. E5B05TAME 1. - IDENTIFICATIONOF SAFFLEST-ED

De8crlptlonor baf’1’le

Wright11-1820~200cyllncler

1s” Top of head ‘1;3;4-,6,72s

!ltandapdheadbarrleInletaideor head 1,2 Standard81debarrleendbarr.1

3s Exhau8taideor head 1,2 Standardsidebarrleandbarrel

4 Inletaideor head 6,7 Standardeldebarrlevlthbarrel

5portioncutOrr

Exhaustsideor head Slmllar to barfle 46 Inlet aide or head ;::,5 Passageconcentricwl%hbarrel

and barrel collects air for coolfng area

7under rear sparkplug

Exhauat aide or 3*4,5 Similar to barrle 6barrel

e Exhaunt aide or head 3 Contoured ror complete contact.with exhauet-port rfna

9 Exhaust side or head 4*5 Serrle over exhaust-port rfnsrained rrom the rin tfps to give

10constant air-passage area

Top orhead 2,5 In ccswplete contact with headrlns except over exhaust-valvearea, where constant afr-paasage

11area Is provided

Inlet side or barrel 6 Cooling air takenfn at rrontisrejected.atnfdesand.new cool-ing alr Is taken In through sidescoops ror rear portion ,Or bar-rel. Fin passages are blockedofr’at air-exchange point.

12 Exhauat side of 6 Similar to bal’rle 11barrel

13 Rear hair or barrel 7 A rectangular duct, concentricwith the barrel and in contactwith the rln tips, directs airrrom both sides or the barrel tothe rlns at the rear. The airentering the rins at the Bidesand at the rear meet and exitthrough tubas across the duct.

14 ToP or head, exhaust o The air la conrined In the rfnside or head, and passages by a layer of sprayedboth eldes or barrel metel bonded to the rln tips.

Aluminum was sprayed on the headrlns and eteel sprayed on thebarrel fins.

15 Area haedlately 8 An air scoop and duct takes airunder reap spark from the rront or the cyllnderplug over the head barrle and to the

fhned area or the head underthe rear spark plug.

Vri@t R-2600-8 rront-row cylinder

41s TOP or head 9 Standard head barrle42S Inlet side or head 9 Standard side bafrle

and barrel43s ~au~u=s;de or head 9 Standardsl~ebarrle

46. Top or head 10 headbarrlewithenlnrge~scoopror directing air into rfns

48above rearsparkplug

Exhaust side or head 10 Air duct around barrel for●nd barrel directing air to area under rear

spark plug49 Inlet ●ide oi’head 10 Ah duct mound barrel to direct

and barrel airto areaadjacentto rearsper~@ug

NATIONAL AOVISORYCOWITTEE FOR AERONAUTICS

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mcA ARR MO. 3KB05 12

TABLE 2. - ~lEATIOll OF BM’FLJJCOMBINATIONS TESZED

Bdflb mu-- Fl& lllue- Ob~ect of tssttng -bhatlau tratlng baffle

ccablnation .

Wright R-1820 G200 cylinder——ls-2s-3s 1 To make reference teats of standard

baffles for comparison with tests& speoial btifles

1.s-2s-3s 1 To show the effect aF incorrectlymounting the standard baffles 2Sand 3S

10-2S-3S 2 To study the effect of a cloee-fIttIng head baffle except for thearea over the exhaust-valve portwhere the baffle was raised abovethe fin tips to provide constantalr-paesage area

I-S-6-7-8 3 To determine the effect of a cloee-fItting baffle over restricted-flow=eas for cnmparlson with 19-6-7-9

1S-6-7-9 4 To show the effect of using a raisedbaffle over restricted-flow areae

10-6-7-9 5 To teet baffle 10 In combination withspecial coollng ducts around thebarrel

19-4-5-11-12 6 To test the effect cd’dividing theair flow around the barrel Into fourpaths

1.S-4-5-13 7 To cool the barrel at the reer withair frcm ecoops on both sides d theberrel

14-15 8 To deterralnewhether a sprayed metalbaffle is practical and whether thebcmd with the fins would Improve thecylinder cooling and reduce the qlrflow

“ Wrl@t R-2600-8 frent-row cyllnder

41S-42S-43S 9 ITo makd reference %ests of etandardbaffles for cwparlson with tests ofspecial befflee

46-48-49 10 To test best ccaubhation of specialbafflee, as deter=lned In frcmt-row

stngle -cy-llnderand tit Icylhdertests

National Advleory Camltteefm Aeronautics

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NACA ARR HO. E5B05

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Fig. la

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Figure 1. - 1820

“ , ,,, , ,. —..-—.,—, -. , , m, , ,

G200

(o) Front uiew.

cylinder, stondard boffles 1S-2$-3S.

,..,. ,.,. ., ... .. .-.— ——. . . . ... . ... ‘.. —-----

NACA ARR No. E5B05

c- f494

(b) f)eor uieu.

Ffgure 1. - Concluded. 1820 G200 cylinder, stondardbaffles 1s-2S-3S.

‘1

)’41

NACA ARR No. E5B05Fig. 2a

(a) Front Uf&W.

Figure 2. - 1820 G200 cylinder, bofftes 10-2S-3S.

...,.

NACA ARR NO. E5B05 Fig.’2b

3s

F{gure’”2. -

\

\

‘\,

NACA .C- 1601

(b) Rear ulew.

Concluded. 1820 G200 cylinder, baffles 10-2S-3S.

,

NACA ARR No. E5B05 Fig. 3a

,.., .

Figure

6

39 - 1820

(a) Front

G200 cylinder,

view.

baffies 1S-6-7-8.

8

7

NACAC- 1679

Iii‘\\“

–%..,,

I

NACA ARR HO. E5B05 Fig. 3b

7

NACAC- 1687

(b) Reor uieu.

figure 3. - Concluded. 1820 G200 cyiinder, baffles 1S-6-7-8.

j

!l’. — —

—-. — ---- ....-———— -—I

HACA ARR

Figure

HO. E5B05 Fig. ~a

4. - 1820 G200

(o) Front ulew.

cylinder, baffles 1S-6-7-9.

NACA ARR Ho. E5B05

.,, . . .

6

(b) Rear view.

Figure 4. - Concluded. 1820 G200 cylinder, baffles 1$-6-7-9.

NACA ARR MOO E5B05 Fig. 5a

7

NACAc- 1407

,

Figure 5. - 1820 G200

(o) Front uf”ew.

cylinder, baffles 10-6-7-9.

NACA ARR No. E5B05 Fig. 5b

Figure 5. -

(b)

Concluded.

--- ..—..- aNACA

C-1488

Rear view.

1820 G200 cylinder, baffles 1o-6-7-9.

I

NACA ARR Mot E5B05

5

Fig. 6a

/s

‘~ C-2399

(a) Front uiew.

Figure 6. - 1820 G200 cylinder, baffles 1S-4-5-11-12.

— —

NACA ARR MOO E5B05

—

Fig. 6b

(b) Rear ulew.

Figure 6. - Continued. 1820 G200 cylinder,baffles 1S-4-5-11-12.

:,

\II ,

HACA ARR Not E5B05

__- —_.. l II

Fig. 6C

front

T

Air f/ou /

I : Iv

IJ .1II

‘k’NATIONAL AOVISORY

COMMITTEE FOR AERONAUTICS

(c) f?arrel cooling-air flou paths, front uieu.

Figure 6. - Continued. 1820 G200 cylinder,botfles 1S-4-5-11-12

—.—.-——

Fig. 6d

Front

NATIONAL ADVISORYCOMMITTEE FOR AERONAUTICS

(d) Barrel c;olingq?lr flow paths, top ufew.

Figure 6. - Concluded. 1820 G200 cylinder,baffles 1S-4-5-11-12.

NACA ARR NO. E5B05

Is

5

. ....

Fig. 7a

NACAc-2397

(o] Front vleu.

Figure 7. - 1820 G2.00 cylinder, baffles IS-4-5-13.

.

- HACA ARR No. E5B05 . ‘“ Fig.

.

/s

,.

4

. .

Figure 7.boffies

NACAC-2398

.0 I 1 I I I6

(b) Reor uleu.

- Continued. 1820 G200 cylinder,1s-4-5-13.

NACA ARR No. E5B05 Fig. 7C

NATIONAL ADVISORYCOWtlTTEE FOR AERONAWICS

(c) Barrel cooling-air flow poths, front view.

Figure 7. - Continued. 1820 G200 cyl inder, ba f fies 1S-4-5-13.

NACA ARR No. E5B05

d h

....-——

Fig. 7d

Frmt

NATIONAL AOVISORYCOMMITTEE FOR AERONAUTICS

(d) Barrel cool ing-air, f low paths, top uiekl.

Figure 7. - Concluded. 1820 G200 cyl inder, baffles 1S-4-5-13.A

!!i .

.-.

NACA ARR NO, E5B05 Fig. 8a

,,

11, /5

(a) Front view.

Figure 8. - 1820 G200 cylinder, baffles 14-15.

.

,

1.-

NACA No. E5B05 Fig. 8b

(b) Rear view.

Figure 8. - Concluded. 1820 G200 cylinder, baffles 14-15.

NACA ARR

.: .:

Fig. 9a

Figure

Ho.

. .

E5B05

4/s

.

9. - 2600-8

b A A A ,.. A A ....

(o) Front view.

cyl inder, front row, boffles 41 S-42S-43S.

.— —

., . ,. ,. .- .. . . . ......... ... ....—---- .-. —.. . . ..—-- .--.-—.—-.......-.--..—.....- -- ..--- -.-— - .---—--———~“

NACA ARR No. E5B05

AI e

Fig. 9b

.

42 S

Figure 9.baffles

CNM$I

(b) Reor vie~.

- Concluded. 2600-8 cylinder, front rou,41 S-42S-43S-

I&l

NACA ARR No. E5B05

49

Fig. 10a

46

Figure 10. - 2600-8

(o) Front u~ew.

cylinder, front row, buffles 46-48-49.

I.

NACA ARR No. E5B05 Fig. 10b

(b) “ Rear uleti.

Figure 10. - Concluded. 2600-8 cylinder, front row,boffles 46-48-49.

. . ..

NACA ARR No. E5B05 Fig. II

.ce”’r’’”’o’b’O”erUC

.i._ :;;bus t /0/7I 10 Orifice

idkRegulot inguoluemotor

Ill I surge tonk—

*

‘1;l\ i1’ :\,,,.F~~

Thermocouple—> Fuei–+ pump

Manometer —

inject ion

Honoae te r

CUEcronkcose

Orifice

Exhomuff

r4 \ A

I !lonometers

Dynamometer

NATIONAL ADVISORYCOWITTEE FOR AERONAUTICS

Figure 11. - 1820 G200 single-cyl !nder-test engine setup.

NACA ARR No. E5B05 Fig. 12Cooling air

Thermocouple

Or/f ic8

I I Honom7ters

II j~”””’exchong”rCold–uoter supply

Droin

Cool lng-oir control uolue

#‘..

:\ # ●7<’ I: -----------------

1“---------E

/0”” nE-----------------1 m 1

--- --~ L,—-- m k

II I

MATIONAL ADVISORYCWMITTEE FOR AERONAUTICS

Figure 12. - 2600-8

Manometer I I II I

singie-cyl inder-test cooiing-oir system.

NACA ARR NO. E5B05 Fig. 13 “

r1 Nmd b#tw#8# values

24 Rear sjorb. plu~ rrant sporb-pl”~●lectrode r2J ●lectrwe—.

s

10

12

14

16

18

20

r.21 [rho”Stroe be?-nrn

bol t, C8Rt#r

-f%+-’“’’’”’’-”0~>22 [.::;;;../”.. ?...,

front spork -filuf bushl.lt

Heed, ●rhoust●nd tone

\

::::; 11 #orrel ?Ll#, ●zhous t

:\

\

: \

: \*lorr.1: tob, f roll t

#Orref ●ld~l., ,.~~

~~

\ 15 8orrel ●ftfdle, ,rhm, t

l’,\

\\ 13 Barrel ●fadt., fromr

lorrel fl. y”g,, l“1, ? \

\

\19 Borre: fionf., ●znm, t

\

#Orr*l 1lan~., -2!+.Lr’”3” ‘“11lorrel ?Ionte, front

f2M3f i~., 20 NATIONAL A9VISORYCOMMITTEE FOR AERONAUTICS

Figure ]> .- Locot ion of the thermocouples on cyllnders.

7,L..,.. ,.-.,,--...---—————- —

,

I(ACA ARR No. E5B05 Fig. IU

\

1S-2S-3S

/S-6-7-8

9

6

/s-4-5-1/-/2

figure 14. - Baffle

i“ /1S-2S-3S

Incorrectly mounted

6

IS-6- 7-9

Is

5

1s-4-5-13

comblnotions tested

10-2s-3s

6

10-6-7-9

/4 -15

NATIONAL ADVISORYCOhWITTEE FOR AERONAUTICS

.

on o Iirlght 1820 G200 -

/“” ;ylinder in single-,cyltnder tests.

~IIw

,.

NACA ARR HO. E5B05- Fig. 15


/

MO /

160

150

140

lyo

2 E~.-l

1202“:&G:~cz~v

60A lS-4-C~ll-12

63- 186=

500 4 6 8

B%fle aoollns-air pressure *OP, ~APS in. HTigure 15.-tests. Indicatedhorsepower, 66; engine speed, 2000 ~; manifola pressure, J1 inohes ormeroury abeolute; fuel-air ratio. 0.M3; Oooli%?.-drtemPOrat~e, 1000 F.

A

4

. ....—.—.. . .-..—.—.— .. .... .——.—..-.—. ————-..—— —...—...-..—

NACA ARR NO. E5B05 Fig. 16

I NATIONAL ADVISORY 1~42tJ~~{COlIWTTEE FOR ‘UitONAUTICS I

? “TmiI

,

1S-2S-3S

Correctly mounted

1 1 I 1 I 1 1 1 1 1 i I I

~. I I I 10 Exhsumt-,alve guide+ Head. between walres1 r

I I I ~ Ueadj exhmuxt end zone❑ Rem spmrkplug bushing

111Rem #park-plug gasket

1A r-r,.. .mm_.-plUg bushimg1

ter-mrm bolt1- “---

. . . .. . .r --

V Exhiust roabD B.rral ❑iddl=, .S-.

V Barrel top, rearv Barrel top. ●verage

Bmtfl@ oeellng+ir we&ure dr~, (Ap ‘~n. E~i~ 16. - ?utorun

~“” Am; =nifol*~*.w..31c. of steaderdbaffles fS-2S-3 oo ● Vri t 1820 G2m oylinder in siB#la-

Oyliador taats.Iodloatcd Msepewer, 66; ●gine apted,lnohes of mtr~ ●bsolute: fuel-air ratio, O.OEJ; oooling-alr tmperatura, ~ ?.

4

L-------- . .. . ..

HACA ARR )(0. E5B05 Fig. 17

I NATIONAL ADVISORY I iCOMMITTEE FOR AERONAUTICS I

/

/S-2S-3SIncorrectly mounted

.

NACA ARR HO. E5B05

—

Fia. 1~

rxmm

L-_--”1S-2S-3S

Correcfjy mounfed

84

-----Oooli~alr flow—Cylinder temperature-

air temperature,M.gG#ling-

+ Head, between valvesHead, exhaust end zone

~ Rear s~rk-plug WshiagO Rear spark-plug gasketA Front spark-plugbushingv Exhaust reeker-arm boltD Barrel middle, rear4 Barrel middle, averageV Barrel top, rearV Barrel top, average

1

0 P 4 6Baffle cooling-airpreezure drOD.=}AP. lII~2H4

-=---

-1

63-192 1

Figure 1S. - m~isa-of sttiti bafflei-~:2s-3s liOOlWeCt4 ~td with t?lSS-bafrleficorreotly moumIndkmated hmrsapoue., E emgys speed, 2000 mm: mamAfoM *r*.sure. 31 imbea of .erouw

on a Wright 1S20G21M oyllnder in slmgla-oyllnderts@s.

absolute;fuel-air ratio, 0. ?~; o-6011*alr te~eratura, 1500 r. “

.. . . . . ..I

. . . . . . .—- .-...—.-- ——-—. - ..—

NACA ARR HO. E5B05 Fig. 19

I I. I NATIONAL AOVISORY* COWITTEE FOR AERONAUTICS

I

1

/0-2S-3S

.!’

Iii

MACA “ARR No. E5B05NATIONAL AOVISORY

CO~lTTEE FOR AERONAUTICS

92

r

Baffle ooolln&alr pre;mre drop. 6Ap, in. H;. - Cmpar180n of spoeial baffles 10-2S-3S

‘i~g;0U120 WOO oylinder in single-o~l~ln;~;t~mead. 2000 rDw: aanlfold Dresnure. 3

Fig. 20

.—.

/0-2S-3S i

/s-2s-3s

-Coollng-alr flow–Oylinder temperature - ooling-

alr temperature, AT, &Exheua+valve guideHead, between valvesHead, exhaust end zoneRear spark-plug bushingRear spark-plug gaeketTront spark-plug buahlngExhauat rocker+rm boltBarrel middle, rearBarrel middle, ●verageBarrel top, rearBarrel top, average

463-19n

a

)rlthztandard barflee 19-2S->S on a

. Indloated horsepower 66; ●ngineIercuryabsolute: fuel-air ratio, 0.0S3:

cooll&alr t;m~erature, l-~o F. - -

HACA ARR No. E5B05 Fig. 21

0-

:,.

HACA ARR NO. E5B05 Fig. 22

IS-6-7-8


1o13

-- --

104

0s 100K

:

.

2* 68:uv

2h: ---40011ng-alr flow

elo a—~llnfler temperature- coollng-alr temperature.AT. W

o+x

76

vD

o 2Baffle ooollog-alr presmwe drop, &Ap, in. B@

‘l#& xgm woo oylinder in single-=. Iin&er tests. Indloated horsepower, 66; enuine● 22. - C~parlson of epechl bafflas 1S-6-7-6 with standaml bamlee N-i?S-3S on a

speed, 2000 rpm; manifold ~eeeure, 3~ inehee of maroury ab*olute; fuel-air ratio,0.0S3;oooliag=air temperature, 100o F.

/

1S-2S-3S

Exhaust-v-dve guide -Head, between valveaHead, exhaust end zoneRear spark-plug bushingRear spark-plug gasketFront spark-plug bushingExhaust rocker-arm boltBarrel middle, rearBarrel middle, averageBarrel top, rearBarrel top, average

63-128


f

‘Baffle-cooling-airpreiauredrop ~~ ,--. RTigure25.- [email protected]. of s ●oial bafffec ?S-&7-9%1 a Wri ht lg20 WOO oylinder in siruIo_

oy~inaer teate. h.ioated fhsepow.r, 66; engine med. 2A ~; wifold ~I#s~. 31inohes or serairy absolute; fud-air ratio. O.OgJ: cooling-air tmporatwe,

I

NACA ARR No, E5B05 ‘Fia. 24

IS-6-7-9

NATIONAL ADVISORY l,,,,i,,,,f.,,,l,rm,i,,., 18*,B8,0,,1,,,T]T,$


log

lob

100

96

+ -/ “ - ‘

92 :w&

/

// “

8.s -

84. 4 /

- .

/ sk

go * -----–Cooling-alr flow–---4Wllnder temD=ature -

\ L

Y \o

76.+x

;Avb

: Qv: v

o 2

/S-2S-3S

alr temperature, AT,Exhaust-valve guideHead, between val~es

coollng-%

Head, exhaust end zoneRear spark-plug bushingRear spark-plug gasketFront spark-plug bushingExhaust rocker-am boltBarrel middle, rearBarrel middle, averageBarrel top, rearBarrel top, average

63A93

2affle coolleair pressure drop. CAP, in. HzOFigure 2U. - Compsr~scm o; special b&fles lS-&7-g-with stamdard baffles 12-2s-3S on amight lg20 G200 oylmder in si%?lec llnder tests. Indicated horsepower ~; ea@ne

coollWJ-alr temperawe, l~p-e’ 3f ‘n&sped, _ W; manifold es of mercury absolute; fuel-a{r ratto, 0.~3;

/7Ii

ARR NO. E5B05 Fig. 25

.

360

340

O* 320

e-4

; yx)I.1<h; 280

.:h.2, 260~

::0 240Ic1h3(3 220:

22& 200

4G

z

~ 120

160

140

120

2affle Oooliag-airWOsoure drop,6-A , 18. I@?igure 25. - hrromanoo of s !

oyllndor t.sto. Indha,od ~ro.pousr, 66; ●rigin.●po.d, 2000 m; untfold ~ro~. 31oiol baffles O-6-7-9 on a Wright 1820 WOO oylinder in s%ngle

laohoo of noroury abaoluto; fuel-air ratio, O.*3; oooling-alr temperature, .

)’>

4—---------. .,,,..,,,,..,,,.,-, ,,.,,,,.., . . .... . ..-.—.

MACA

—

\

,.’

ARR NO. E5B05~, COMMIT ‘EE FOR AERONAUTICS

● ,.

112

100-- .-

--- -. --

104 -

~ loo

& ‘ -< – — – – > *

/

~ –

Fig.

6

“~10-6-7-9

-----oooliwair rxow—Qlindort8mperature - oooliag-

.: •i~ temperature M, WO ~U8t-VdVO midg+x

v

v

o s

/s-2s-5s

63-x$6

;

NACA ARR MO. ESB05 Fig. 27

H“a

Fr

lS -4-5-11-12

‘0, ‘$ /;Front

khaust-v~lvo guide.Head, botwaorn ~81VC8lb-d, ●xhmust ●nd SOnORoar spmrk-plugbushimgRoar ~p6rk-plug g~mkotFront spark-plug .bushiagkhaust rookor-srn bolt

Bsrrol ●iddlo, roarBarrel middla, ●voragoBurol top. roarBmrral.top. ●varaga

d


...L

)S-4-5-11-12

osK

NATIONAL ADVISORYCOWAITTEE FOR AERONAUTICS

/10s

104

100

96

92

88

84

----(?oollng-alr flow—L&llnder temperature - 6;ollng-

air temperature. AT.o+x

v

4

0 2Baffle ooolhg-alr preseure drop, fbp, in. I@

Figure 2g. - Comparleon of @peoial baffle* lS-k5-11-12with standard baf f lee lS-2S-3S on aWright lg20 13200 eylindcr in single-o linder tests. Indloatecl horcpower, 66; engine

epe-$ - ‘~; “ai’o’d &&i’;: e, 31 inohes of mercuryabsolute; fuel-air ratio, 0.063;ooollng-air temperature, 1

“.-

1S-2S-3S

Exheuat+valve guide -Head, between valveeHead, exhaust end zoneRear epark-plug buehingRear spark-plug gaeketFrOnt 6~rk-phg bueh.lngExhaust rocker-arm boltBarrel ml~dle, rear”Barral middle, averageBarrel top, rearBarrel top, averaga

‘1

MACA ARR NO. E5B05 Fig. 28

u


/108

104

100

96

92

WS

84

- ---Ooollng-alr flow—Oylinder temperature - ~ooll

a.lr temperate, AT, Fo Exhauet-valve guide+ Head, between valveax Head, exhauet end zone0 Rear spark-plug bushingO Rear spark-plug gaeketA Front 6~rk-plUg bushingV Exhaust rocker-arm boltD Barrel middle, rear4 Barrel middle, averagev Barrel top, rearU Barrel top, average

o ?Baffle o~ollag-alr preee&e drop; cAp ,–~n. H$

L ..:

1S-4-5-/1-12

1S-2S-3S

m-

d

..

Figure 2g. - Comparison of speoialbaffle= 1S-4-5-11-12with standardbarrlec lS-2S-3Son aWright 1820 WOO oyllndcr 18 single-e linder te6te. Indloatad horcpower,66; engine

“e@’ - ‘; ‘m’’O1d l%i?sfw’ 3{ In.hee of meroury absolute; fuel-air ratio, 0.02J;

oooligalr temperature. 1

NACA

“.4UY

y30

360

90

!-.+~ 260

.5-i000 240

L 200

160

140

120

100

ARR No. E5B05 Fig. 29

r 1~NATIONAL ADVISORY


o 2

Is i

m1s-4-5-13

A

\Frmi

.--1A••+ñ•Ø‹X

0 Exhaust-valve guide+ Head, between valves“ Head, exhaust end zone0 Rear spark-plug bushingO Rear spark-plug gasketA Front ppark-plug bushingv Exhaust rocker-arm bolt

D Barrel middle, reard Barrel middle, averageVBarrel top, rearw Barrel top, average 1

$3-6.. .

Baffl; coollng-alr pr~ssure &op, fA~” in. H~~Figure 29. - Performance of special baffles lS-~5-13 on a Wright 1S20 WOO cylinder in single-

cylinder tests. Indicated horsepower, 66; engine speed, 2000 rpm; ma”nlfold preaeure, 31inches of mercury 8b60hIt8; fuel-air ratio, O.OS~; cooling-air temperature, 10@ F.

NACA ARR Moo E5B05 Fig. 30

Is

~

1s-4-5-/3

NATIONAL ADVISORY. .,.f -,,1.~,,1..~

COMMITTEE FOR AERONAUTICS.

104-

5

96Y ‘

92-

&6:

?44-

g --––Cooling-air flow—Cylinder temperature - coollng-

alr temperature, AT, oFO Exhauat-valve guide+ Head, between valves

7 x Head. exhaust end znn-

7I I I lb

I I I ID

v

6d\

i

60 2 4 6 8

1S-2S-3S

—H-H-HO...—-----

0 Rear-spark-plug buahlng

Rear spark-plug gasket .Front Epark-plug bu6hlngExhaust rocker-arm boltBarrel middle, rearBarrel middle averageBarrel top, rearBarrel *OP. average

BUfle oooling-alrpraasure drop, fbp, in. H@

“wre 2°”- Comparlcon of epeoial baffles 1S-4-5-13 with standard baffles 1S-2S-3S on ●

Wrlgh 1S20 11200oylinilerin single-o linder tests. Indicated horsepower 66; engineqpead, 2000 rpB; manifold Prsssure, 3~ inches of utermury absolute; fuel-afr ratio, 0.0g3;oooling-air temperature, 100 F.

J— -.

NACA ARR NO. E5B05

L0

&-a

t.!..4(d

*

:000

Fig. 31

- Barrle-oooliqt-ah w~sare&OP. fbP, in. Wri.gure31.- ?erfomauoe of s eoial barfl

F4oylhder test6. Indioated oreepwer,-1 on a Wright lg20 G200 OY1indar in eingle-

~~;l’&?n. speed, 2000 ~; asnifold ~r~, J1inohes of moroury absolute; fuel-air ratlo, 0.W3; cooling-alr temperature, .

/~

.—

,,

H.ACA ARR No. E5B05 Fig. 32

/4- 15

\

1S-2S-3S

“%% kOO cylinder in shL@e-o Modcr tests. ‘Indloatad hor’mmwm 66; ●ngine s cad,e 2. - Oasparieon o; apeclal ~~lee i4-15wlih ctandardbaffles 1S-2s-3s 00 ● wright

1 indm. of meroury absolute; fuel-alr rat%o, O.OJJ; ooolins-2000 rpm; manifold ~e;eure. 3●lr temperature,100 .

q,

d-,., , , ,..–.......–--.—.. .... . —,...-..--—....-— ..--..——.

NACA ARR NO. E5B05

4).s

Fig. 33

41S- 42S- 43S

8sffle coolin&air pressure drop, &Ap, in. H20Figure 33, - Performance of standard baffles 41S-42S-43S on a Wright R-2600-8 front-row

cylinder in single-cylinder tests at an indicated horsepower of 78. Engine speed, 2100rpm; manifold pressure, 31 inches of mercury absolute; fuel-air ratio, 0.075; cooling-air temperature. 100” F.

/14

NACA ARR MOO E5B05 Fig. 3*

: 4+++1-1NATIONAL AOVISORYCCUMITTEE FOR AERONAUTICS I

46-46-49

2+ 16

u- 1 I 1 I I 1 1 1 1 I 1

0 Exhaust-valve guide 11

I“ Head; exhaunt end zo~e❑ Remr spark-plug bushingO Rear spark-plug gasket

1 i

I 1 I I + Elead.between valves u

-1 , ,

I I I I I o B~rrel ~~ddl~, •,~r.ge

v Barrel ton. rear1

m

10

--r.

I I Iq Barrel top, ●versge

I I 1

:at663

1 I I I I I I I.

Baffle cooling-air pressure drop, 6AP, in. H20

Figure 34. - Performance of special baffles. 46-48-49 on a Nrigbt R-2600-8 front-row cylinderin sinfile-cylinder tests at an indicated horsepower of 78. En@ine speed, 2100 rpm; mani-fold pressure. 31 inches of mercury absolute; fuel-air ratio, 0.075: cooling-sir tempera-ture, 100” F.

.

MACA ARR NO. E5B05 Fig. 35

cl2>d

>-

2u

5dI

~

.-l

~v

Baffle cooling-air pressure drop, uAp,in. H20Figure 35. - Cooling-air flow for the baffles on a Wright R-2800-8 front-row cylinder in

single-cylinder tests at an indicated horsepower of 78. Engine speed, 2100 rpm; mani-fold pressure, 31 inches of mercury absolute; fuel-air ratio, 0.075; cooling-air tem-perature, 100° F.

ltACA ARR MO. E5B05 Fia. 36

120

112

n

I

48

46-48-49

4/.s

1I

L ‘bK!-Lm! , 1 ..C

V

4/ S-42 S-43S

air temperature, M,Exhaust-valve guideHead, between valvesHead. exhaust end zone

76 +x

:.- A

E!

v>4

Lvv

\

ited horiepow er, 78 .

Rear-spark-plug buehlngRear spark-plug gasketFront epark-phg buahlngExhauat rocker.arm boltBarrel middle, rearBarrel middle, averageBarrel top, rearBarrel top, average

1“64-43

Baffle cboling-air preaaure drop, GAP, in. H20

Figbe 36. - Comparison of apeoial bafflea 46-48-49 with standard baffles 41S-42S-43S onWright R-2600-8 front-row oylinder in single-oylinder teats at an indicated horsepowerof 78. Engine speed, 2100 rpm; manifold pressure, 31 inches of mercury absolute; fuelair ratio, 0.075; cooling-air temperature, 100° F.

Ad

a

—.

IIACA ARR No. E5B05 Fig. 37

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1 II I 1.1 I I 1 I

I

1

d

4/s

41S- 42S-43S

42 S

1 1* _~

T

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HATIONAL ADVISORYCOWITTEE FOR AERONAUTICS

3

32

20

L ~ . . . . .hA

A

x

+

1\

4

1

hffle molin~-air pressure drop. tiAP, in. HzO

I

Exhaust-valve orownExhaust-valve guideFront spark-plug electrodeFront s~ark-plug bushingRear spark-plug electrodeRear spark-plug bushingRear spark-plug gasketIiesd, exhsust end zoneHead, between valvesExhaust rocker-arm boltBarrel top. remBarrel top, averageBarrel middle, rearBarrel middle, average H

gure 37. - Performance of standard bafflea 41S~42S-43S on a Wright R-P.600-8 front-rowcylinder in single-cylinder tests at an indicated horsepower of 103. Engine speed, 2100rpm; manifold pressure. 3S inches of mercury absolute; fuel-air ratio. O. 10; cooling-airtemperature, 90” F.

NACA ARR No. E5B05 Fig. 38..

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I NATIONAL AOVISORYCOMMITTEE FOR AERONAUTICS I I I I I

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520

4s0 \ok

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I IRIIII III II

46

46-48-49

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$z 360 +000

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Cl

~ 320

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240

. Exhaust-valve crown0 Exhaust-valve guide

200 k Front spark-plug electrodeQ Front spark-plug bushing4 Rear sptrk-plug electrode

\

~ ~~a~ svrk-pluj! gasket, exhaust end zone

+ Head, between valves

V Exhaust rocker-arm boltF Barrel top, rear

D Barrel middle, rear

120Q Barrel middle. average

%

u Wr18d Jlcica Bwma a & . . . — — . — —

60

Baffle cooling-air pressure drop, O-Ap.-ln. H20

Figure 38. - pCrfOrE~IICC of Suecial baffles 46-48-49 on “a !lrieht R-2600-8 front-row cylinderin single-cylinder tests at”an indicated horsepower of 103.- Engine speed, 2100 rpm-: mani-fold pressure. 38 inches of mercury absolute; fuel-air ratio,90” F.

0.10; cooling-air temperature,

.


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96

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46-48-49

al c

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+r, 103 v

4/S-42S-43S

Cylinder temperatur~;cooling-airtemperature, AT,

Exhaust-valve crown iExhaust-valve guideFront spark-plug electrodeFront spark-plug bushinERear spark-plug electrodeRear .vpark-plug bushingRear spark-plug gasketHead, exhaust end zoneHead, between valvesExhaust rocker-arm boltBarrel top, rearBarrel top, averageBarrel middle, rearBarrel middle, average 54-’73

\ vw

o a 16 * 32Baffle oooling-air pressure drop, <Ap. in. H20

Figure 39. - Comparison of speaial baffles 46-46-49 with standard baffles 41S-42S-43S on al?g~ght R-2600-8 front-row cylinder in single-cylinder tests at an indicated horsepower of

. Engine speed, 2100 rpm; manifold pressure, 38 inches of mercury abmolute; fuel-airratio, O. 10; cooling-air temperature’, 90” F.

—.

●

NACA ARR moo E5B05 Fig. UO.

>

.,

46-48-49

.

4/S-42S-43S

—Standard baffles 41S-42S-43S--–--Special baffles 46-48-49

~ ~a;;efpark-plug gasket, middle rear

,36-:

.“ Bafrle-ooollng~alrPriimure drop, ~Ap, in. %?O

Figuro bO. - Comperieonof special baffles 46-48-49endatandsd baffles h3-k28-439 oncylhd- 2 of the front rcw of a wright ~zmg engina In multieyllqder ●nglne teata.Brake horsepower, 925; engine speed, 2100 W; manifold pressure, 31 Inohas of ●orouryabsolute; fuel-air ratio, 0.075.

d.-..’-------- –-.

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