—.— —

n

FORAERONAUTICS

TECHNICALNOTE2503

HYDRODYNAMIC INVESTIGATION OF A OF HULL MODELS

SUITABLE FOR SMALL FLYING BOATS AND AI@UD131ANS

By w.c.

Stevens

Hugli,Jr.,andW. C.Axt

InstituteofTechnology

Washington

November 1951

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TECHLIBRARYK.MB,NM

NATIONALADVISORYCOMMZPTEE

“

llllUllFORAERONA0171Cb 00b5505

TECHNICALNOTE2503

HYDRODYNAMIC~IWION OFA SERIESOFHULLMODEI+3

SU73X3LEFQRSMALLFLYINGEOA!l!SA?U)AMPHIBIANS

ByW. C.Hugli,Jr.,andW. C.Axt

SUMMARY

Thisreportpresentstheresultsofan investigationmadeattheExpertientalTowingTank,StevenshstituteofTechnology,to obtainhydrodynamicinformationona seriesofhullmodelssuitableforsmallflyingboatsoramphibiansoffrom2000to 5000poundsgrossweight.Theseriesofhullsconsistedofa basichullwithsimplelines,andofplusandmtiusvariationstothisdesigninwhichthebeam,stern-postangle,andafterbodylengbhwerealtered.Modificationswerealsoinvestigatedto determinetheadvantageofrefiningthehulllines.

.

Thehullsweretestedforhydrodynamicresistanceandmainspray.Onthebasisofthesecharacteristics,thebestbeamandsternpostanglewereselectedforeachofthethreeafterbodylengthsinvestigated.Theresultingthreehullswerefurthertestedforlandingandporpoisingcharacteristics.

Theresultsshowthatitispossibleto designa hull.withsimplelinesthatwillbe suitableforsmallflyingboatsoramphibians.Refiningthehulllineswillimprovethehydrodynamiccharacteristicsslightlybutwillalsoincreasetheconstructioncost.

INTRODUCTION

Inrecentyears,theextensivedevelopmentactivityinflyingboatahasbeendirectedtowardlargemilitarydesignsalmosttotheexclusionofworkondesignproblemspeculiarto smallflyingboatsinthepersonal-ownerclass.Thelastcomprehensiveworkonsmallflyingbeatswasthatundertakenby theNationalAdvisoryCommitteeforAeronauticsin1934onthemodel40 series(reference1). Thesignificantadvancesinhydrodynamicresearchsincethattimemadeitappearthely tomakea newaadmoredetailedinvestigationof a seriesofhullmodelssuitableforsmallfl@g boatsandamphibiansrangingfrom2000to 5000poundsingrossweight.Suchan investigationwascarriedoutattheExperhental

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2

TowingTank,StevensInstituteofTechnolo&y,withthefinancialassistanceoftheNationalAeronautics.

Thehulldesignproblemsof largeflying

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underthesponsorshi~andAdvisoryCommitteefor

boatsaredifferentfromthoseofsmallfly&gboats.Thelargerhulis,generallyhavinglowerpowerloadingsandlowertake-off-speedcoefficients,arelesssensitivetothehydrodynamicresistancecharacteristicsthanthesmallerhulls.Furthermore,whileit i-sfeasibleto incorporateintothelinesofthelargerhullssuchrefinementsas chineflareanddead-risewarping,thelinesofthesmallerhullsmustbe as simpleaspossibleinordertokeepconstructioncostswithinreasonablelimits.

Inan investigationsuchasthis, wherethegoalof satisfactoryhydrodynamiccharacteristicsmustbeattainedwitha simpleform,thehulldesignonwhichthestudyisbasedgreatlyinfluencestheultimatevalueofthework. To thisend,thebasichullusedinthisinvesti-gationwasdesignedwithsimplelinesonthebasisofpreviousmodeltestsandgeueralexperience.Theseriesofhullsconsistedofthebasichullandofvariationstothisdesigninwhichthehullwidth,afterbodyle?gth,andanglebetweenforebodyandafterbodywerealtered.Inorderto detemninethepossibleadvantagestobe gainedby refiningthehulllines,twoalterationstotheforebodyandonealterationtotheafterbodyofthebasichullweretested.

Theinvestigationwascarriedoutinfourphases.First,brieftestsweremade>0 determinea longitudinalpositionofthecenterofgravitywhichcouldbe usedforallofthehulls.Second,becaweoftheimportanceofresistanceandmainspraywithrespectto smallflyingboats,thesecharacteristicsweredeterminedforallhulls.Third,onthebasisofthesetests,thebestbeamandsternpostangleforeachafterbodylengthwereselected.Theresultingthreehulls,eachofdifferentafterbodylength,werethentestedforlandingandlongitudinalstability.Finally,forebodyandaf%erbodymodificationswereinvestigatedto determinetheiradvantages,ifany,overthesimplifiedhulllines.

DEFINITIONSANDSYMBOLS

Thetermsandsymbolsusedinthisreportaredefinedas follows:

‘A loadcoefficient(A/wb3)

speedcoefficient(v/@)

)

c.

—.——— .— —— . -—— . .

NACATN 2503

.

,.

CR

CD

CM

Cx

c~

CL

Lf/b

La/b

k/L.

/MqV+b4

A

w

b

v

13

R

D

A,

Pa

P~

resistancecoefficient(/ )R wbs

(l@$v=)air-dragcoefficient

tr~ing-momentcoefficient(/ )M wb4\ .

(/)longitudinal-spraycoefficientX b

([)vertical-spraycoefficientZ b

liftcoefficient

ratioof forebodylengthtobeam

ratioofafterbodylengthtobeam

pitching“~adius”constant

aerodynamicpitch-damping

loadonwater,pounds-

specificwei~t

maximumbeamof

speed,feetper

ofwater;

constant

62.3

hullat chine,

second

poundspercubicfoot

feet

accelerationdueto gravity;32.2feetpersecondpersecond

resistance,pounds

airdrag,pounds

maxinnmcross-sectional0.185squarefeetfor

areaofmodel,squarefeet;modelswith6-inchbeam

massdensityofair,pound-secondssquaredperfoot4

massdensityofwater,pound-secondssquaredperfoot4

-. .— . —— .—. —_________ ___ _—___ . _______ ______ __ _

4 MACATN 2503

M trimmingmoment,pounds

x . longitudinalpositionofmain-spraypointoftangency,measuredfore(positive)oraft(negative)ofthestep, Ifeet

z verticalpositionofmain-spraypointoftangency,meas-uredfromtangentto forebodykeelatmainstep,feet

k forebodylength,measuredfromintersectionof chineandkeelto stepalonga lineparalleltotangentto fore-bodykeelatmainstep,feet

La afterbodylength,measuredfromstepto sternpost,feet

L totallength,forebodyplusafterbody,feet

k pitchingradiusof gyration,feet

Mq aerodynamictail-dampingderivative(seesectionentitled“ApparatusandProcedure”forcompletedefinition?)

s fullscale,usedas a subscript

m model,usedasa subscript

h stepheightatmatistep,percentofmaximumbeam

a sternpostangle,anglebetweentangentto forebodykeelatmainstepandlinejoiningtipof stepandthestern-post,degees

Pf forebodydeadriseat keelandmainstep,degrees

T trti,anglebetweentangentto forebodykeelatmainstepandfree-watersurface

Momentdatasrereferredtothecenterof gravity,andwatert.rhmdngmomentswhichtendto raisethebowareconsideredpositive.Thecoordinatesofthecenterof gravityaremeasuredabovethetangenttotheforebodykeelatthemainstepandforwardofa planeperpendi-culartothekeelandpassingthroughthestep.

.

. ——— —.———-— .—-—..— —----- .—.-

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.

,

Thefollowingcombinationsofthecoefficientsdefinedaboveareused:

Coefficient Symbol Takenfromreference-

Planingrange.

Lift ~dcv 2

Resistance @% 3

Displacementrange

Speed C#@3 3

Resistance @@A2/3 3

Longitudinalspraydc cA113 k

Verticalspray/

c~ CL 4

Thenumericaldesignationofeachmodel(shownonthesumuarycharts)describesthep~incipalhullproportions.Thus,ifa modelhasthedesignation

.

itmeansthatthisnumerical

3.25- 1.04-20

~lb = 3.25,h/a= 1.04,and f3f= 20. Thebasisformodeldesignationisexplainedinreference5.

Thisinvestigationhullsforamphibiansofhydrodynamictestsover

DESCRIF’IIOIVOFMODELS

Over-AllDesign

wasundertakentoprovidedesigninformationonfrom2000to 5000poundsgxossweight.Bysufficientlywiderangesof get-awayspeed

makingand

..—.

6

loading,itwasfeasibleto formtheseriesaroundahavingan intermediategrossweightof3000pounds.

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singleprototypeThegeneralpro-

portionsfora hullofthissizewerebasedto someextentonpublisheddesigninformationgivenh reference6. HulldimensionsofvariouEsmallamphibians, scaledtoa grossweightof 3000pounds,aregivenintableI. Onthebasisofmoderntrends,a forebodylengthof156incheswaschoseninpreferencetotheaveragevaluegivenintableI. Thenormalbeamwasselectedas48 inches,withalternatevaluesof42and54 inches.

Afterbodiesofvaryinglengthwereincludedintheinvestigation.ThevaluesoftaillengthgivenintableI wereusedasa guideinselectingthelongestlengthofafterbodywhichwas216inches.Theshortestafterbodylengthof 108incheswasselectedas comparablewiththatusedinpreviousdesigns.Thenormalafterbodylengthfortheserieswastakenhalfwaybetweenthelongandshortafterbodylengths.Consequently,aswillbe notedinthetabulationofmaindtmensionsbelow,thebasichullofthefamilyhasanafterbodylengthsomewhatgreaterthantheaverageofafterbodylengthsobtainedfromtableI.

Thefollowingfull-sizeprototypemainhens ionswereincorporatedinthebasichull.TheaveragedesigndimensionsobtainedfromtableIarealsopresentedforcomparison.

Dimension kS iChull AverageE.T.T.model102LO1 givenintableI

Grossweight,pounds 3000 3000Forebodylength,inches 156.0 140.7Afterbodylen@h,inches 162.0 111.8Beam,maximum,inches 48.0 -----Beamat step,inches 47.72 47.2Deadriseat step,degrees 20.0 lg.8Stepheight,inches 4.0 3.2Afterbodyangle,degrees -----Sternpostangle,degrees ;:: 9.4Modelscale 8.0 -----

TableIIgivesadditionalparticularsofthebasichull.

.,

...—._ ———. —— . —— .—— .-

mcA TN 2503 7

Forebody.-Whereverpractical,thehulllineschosenweremadeupfromreadilycomputablecurves- a processwhichpermitsconvenientscalingofthelinesup or down. Inaddition,thisproceduxehascon-structionadvantagesbecauseitfacilitatestheaccuratejoiningofcomponentportions.

The“forebodyflat”- theregioninwhichthedeadriseincreaseslinearlywiththedistance.forwardofthestep- is34.6percentoftheforebodylength.It issufficientlylongto satisfytheneedofplaningareaat thehump,andyetshortenoughto obtaineasybuttocklines.Thevariationindead-riseanglewithforebodylengthisshowninfig-ure1. Thedeadriseat thebowofthesmphibianis45°. Itwasnotdeemednecessarytomakethebowdeadriseashighas iscustomaryonmilitaryflyingboatssincethewholeforwardportionofthebasicforebodywasliftedrelativelyhigherabovethebaseline.&caWe ofthehigher-placedbowsections,thebasicdesignshouldbe abletooperateinwavesof greaterheightthanpreviouslybuiltflyingboatsofthesizecontemplated.

Thekeelcurvature,startingattheforwardendoftheflat,isofessentiallyellipticalform,as showninfigure2.

Beam.- A maximumbeamof48 inches,occurring24 inchesforwsrdofthew~step, wasselectedforthebasichull. Placingthemaximumbeamforwardofthestepyieldsthemaxhnumwettedareafora givenwettedlength,a conditiondesiredathumpspeeds.AE thespeedincreasesandthewettedareadiminishes,thewettedlengthbecomesexcessivelyshortfora givenbeau;itisthereforeadvantageoustohavea smallerbesmat thestep.Thisexpedientprovidesbotha greaterareaforwardanda greaterspaceforthecockpit.Inaddition,itprovidesforfinerlinesaft,thusreducingafterbodyinterferencewithsprayfromtheforebodyathighspeeds,andalsoreducingtheskinareaofthehullwhichwouldtendto reducebothweightandcost.

Theplanoftheforebodychinelinefromthebowtothemaximumbeamat station132is,essentially,ofellipticalform.Fromsta-tion132to thesternpostoftheafterbody,theplanformisa modifiedparabola,as indicatedinfigure3.

Mainstep.-Thedepthof thestepinfluenceslandingstabilityandresistanceathighspeeds.A stepdepthof4 inches(8.3percentofmaximumbeam)wasselectedforthebasichull. The4-inchstepheightappearstobe adequatewhencomparedwiththeinformationontheinflu-enceofvariouEhullparametersuponskipping(seereference7). A

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8 wmim 2503

laterreport(reference8)notavailableatthetimethesehullsweredesignedgivesadditionaldesignin.fomnationonstepdepth.

Afterbo&y.- Thedead-riseangleoftheafterbodywasmaintatiedat 20°throughoutthelengthoftheafterbody.

Tailconeswerenotincluded.Afterbody-roachprofilemeasurementsfortheshortafterbodiesatprehumpspeedswereincludedinthetestprogramto aidthedesigner.

Spraystrips.-Shple spraystripsofthetypeshowninfigure4wereattachedtotheforebodesinorderto controlthespray.

Lines.-Thelinesthusderivedfortheparentmodelwithvariationsofafterbodylengthareshowninfigure~.

.

HullSeries

Theblockgrid,figure6,showsthebasicmodelandtheplusandminusvariationsinbesm,sternpostangle,andafterbodylengthofthebasicdesignmakingup thehullseries.

h derivtigthehullsofwiderornarrowerbeam,theforebody-helprofileandthedead-riseanglesofthebasichullwereunaltered.Thus,thechineheightsabovetheforehodyhel variedforhullsof differentbeam,butthelateralandlongitudinalanglesoftheplaningb@mmremainedconstant.Theforebodyplainformwasalteredwithchangeinbeam,becausethevalueofthebeam b enterstheforebody-plan-formeqmtiongiveninfigure3. Theafterbodyplanformwasalteredwithchangeinlengthandbeamby changingthevaluesoftheconstantsintheequationofafterbodyplanform.Thevalueoftheconstantp wasdeteminedby thebeamandafterbodylength.Theexponentwastakenaa 2.25forthelongafterbody,2.50forthemedium-len@hafterbody(parent),and2.75fortheshortafterbody.

Thechangeinsternpostanglebodyabouttheintersectionoftheofthemainstep.

Thelinesoftheothermodelsand8.

wasaccomplishedby rotatingtheafter-afterbodykeelwiththeverticalplane

in theseriesareshowninfigures7

—.. .—_ —. —— —_____

2

.*

,.

,.

NACATN 2503 9

HullModificationstoParent

Thehullserieswasdesignedwiththeobjectof obtainingsatis-factoryhydrodynamiccharacteristicswith“simplified”lines.Sinceoversimplificationcouldresultinhydrodynamicpenalties,tworefine-mentsoftheparentforebodyandoneoftheparentafterbodywereinvestigated.

Concaveforebodybottom(modelno.1220-01).-Thechineandkeellinesoftheparenthull(modelno.1024-01)wereretainedbutthebottomwasmadkconcaveandno chinestripswereused(fig.9).

Increasedforebodydead-risewarping(modelno.1222-01).Thedeadriseoftheparent.forebodywaaincreasedforwardof station102 .tothebow. Theincreasewasobtainedby droppingtheparentkeellineandraisingthechinelineequalamountsateachstation(figs.1 and9).

Afterbodydead-risewarpingmodelno.1221-ol).- Theconstantafterbodydeadriseof20°wasalteredtohavea maxtiumdeadriseof 33°atstation237(figs.1 and9).

APPARATUSANDPROJEDURE

Thetestfacilitiesoftank3 oftheExperimentalTowingTankaredescribedinreference9. Theapparatusemplo~dinconductinggeneraltestsforresistance,main-spray,andporpoistigcharacteristicsofflying-boathullsisshowninfigure10.

Withbuttwoexceptions,alltestswereconductedinsmoothwaterata seriesof constantspeeds;bow-spraytestsweremadeinwaves,andlandingsweremadeasthetowingcarriagewasdecelerated.

Theparabolicunloadingcurvesgiveninfigure11showtheupperandlowerlimitsoftheloadingrangeusedintheresistance,spray,andporpoisingtests.

Theresistanceinvestigationwasmadewiththemodelsfreeto triminthedisplacementspeedrangeandat a seriesof fixedtrimanglesintheplaningspeedrangeovera widerangeof load.Inalloftheresist-ancetests,a 0.040-inch-diameterstrutwastowedaheadofthemodelto induceturbulenceinthemodelboundarylayer.Ithasbeenfoundfrompasttestingexperienceatthistankthata definiteimprovementintheuniformityandreliabilityofthedatacanbe obtainedwithinducedturbulence.Theresistanceincludestheairdragof themodel,butdoesnotincludetheairdragoftheapparatus.

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10

thethe

Themain-spraytestsweremademode1sfreetotrtiovera wide

inthedisplacementrangeof load.The

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speedrangewithdimensionsof

main-sprayblisterwereobtainedbymeansofthree-viewphotographs.Withtheaidofmirrors,a cameramountedabovethemodels~~t~eo~lYrecordedtop,front,andsideviewsofthesprayblister.Thisphoto-graphictechniqueisdescribedInreference10.

Generalporpoisingtestswererunata numberof ftiedspeeds,thechoiceofspeedsdependingontheload.At eachspeed,momentswereappliedto covera rangeoftrimssufficientto embracetheupperandlowerstabilitylimits.At eachspeedandappliedmomenta testwasmade

. withdampinginpitchobtainedbymeansofa calibrateddashpot=dpiston.Theaerodynamicpitch-damptigrate ‘q forthehorizontaltail

alonewasdetermtiedfromtheequationgivenh reference2:

()Mq = K!!‘t%% % t poundsfeetseconds/radian

wastakenas 1.00.Thevaluesoftailarea St andweretaken-fromtheaveragesgivenintable1. Thewascalculatedfromunpublishedcurtiesofwind-tunne1

testsf&nishedby oneoftheaircraftmanufacturers.Forthisinvesti-gation,a pitch-damptigratecorrespondingto ‘q = 7.53X 10-%m wasused.

.ThespecificporpoisingapparatusshowninfigureI-2anddescribed

inreference11wasusedinconductingthelandingtests.Thisapparatusisequippedwitha hydrofoilwhichiscalibratedtoprovidethescaleaerodynamicliftforcesandforcederivatives.An attemptwasmadetoduplicatethefull-sizelandingmaneuveras closelyaspossible.Whileintheair,themodelwasacceleratedtowelloverthelandingspeedwithenoughappliedmomenttoholditat somepredeterminedlandingtrti.Themodelwasthendeceleratedattherateof 2 feetpersecondpers~conduntilit landed.Fromtheinstantthatdecelerationbegananduntilafterthemodellandedthemodelheaveandtrimwererecorded.Thenumberofskipscanbe determinedfromsuchrecords.

Thelandingtestsweremadeat onegrossweightandtwowtigloadings.Thelandingtrimanglewaqdeterminedby thewingcharac-teristicsas a functionofwingloadingandspeed.Curvesof landingtrimagainstlandingspeedforthetwovaluesofwingloadinginvesti-gatedareshownb figure13.

-— —.. — ——. - -.

NACATN 2503 IL

Therewere27possiblehullcombinationsofvariationsinbeam,sternpostangle,andafterbodylength,as showninfigure6. Itwasthoughtbestto selecttheafterbodylengthastheindependentvariable,thusnarrowingtheproblemto theselectionoftheproperbeamandstern-postanglefora givenlengthofafterbody.At theoutsetofthepro-gram,itwasanticipatedthatthe8 extremecombinationsofbeam,stern-postangle,andafterbodylengthcouldbe omitted,therebyreducingthenumberof combinationsto 19. However,testresultson someofthe .othermodelsindicatedthat4 oftheextremecombinationsshouldbetestedbutthat2 ofthe19combinationscouldbe omitted,sothat21ofthepossible27combinationswereinvestigated(seefig.6).

Theinvestigationwascarriedoutb fourphases.Inphase1,preliminaryporpoisingtestswereundertakento selecta suitablevalueforthedesignpositionof’thecenterof gravitytobe usedinallofthetests.Bymakingbriefporpoisingtestsonthehullhavingthewidestbeamandlargeststernpostangle(shortestforebodywettedlength),withvariouslongitudinalpositionsofthecenterofgravity,itwaspossibleto selecta center-of-gravitylocationsufficientlyclosetothesteptopreventlower-limitporpoisingnearhmp speed.Bymakingbriefporpoisingtestsonthehullhavingthenarrowestbeamandloweststernpostangle(longestforebodywettedlength),withvariouElongi-tudinalpositionsofthecenterof gravity,itwaspossibleto selecta center-of-~avitylocationsufficientlyfarforwardofthesteptopreventupper-limitporpoising.Thus,a center-of-gravitylocationdeemedsatisfactoryinthesetwoexbemecaseswasselectedfortheentireseries.

Theresistanceandmain-spraycharacteristicsarethetwomostimportaut,,bydrodynamiccharacteristicsina studyofthistype. Inphase2,therefore,all21hullcombinationsweretestedforresistanceandmain-spraycharacteristics.

Onthebasisofthetestsinphase2,threehullcombinations- oneforeachafterbodylen@h- wereselectedforfurthertesttig.Twoofthesethreehullswereinvestigatedforlandingcharacteristics.Sticeitwasknownthatthedepthofstepinfluencesthelandingstability,oneofthesehullswastestedwithno-l anddecreaseddepthofstep.Porpoistigtestswerethenmadeoneachofthethreehullcombinationsat thebeststepdepth.Thisportionoftheworkwasdesignatedphase3.

—— . -- .—-—— — —— .——— ——— .—

12

Phase4 wasplannedinordertoofusingtesteddesignrefinements.investigatedwereas follows:

Refinement

Concaveforebodybottom

Increasedforebodydead-risewarping

Afterbodydead-risewarping

NACATM 2503

determinethepossibleadvantagesTherefinementsandcharacteristics

Characteristicsinvestigated

Low-speedresistanceandmainspray

Low-speedresistance,mainspray,bowspray,andlower-limitporpoising

Landingandhigh-speedresistance

RESULTS

Center-of-Gravity-LocationTestData

Theresultsofthepreliminaryporpoisingtestsmadeonthebulbwiththewidestbesmandlargeststernpostangle(shortestforebody

.

wettedlength)andwithnarrowestkam andloweststernpostangle(longestforebodywettedlength)to determinea longitudinallocationforthecenterofgravitywhichcouldbe usedforallofthehullsaregiveninfigure14. Althoughthechangesincenter-of-~avitylocationdonotaffectthetrimltiitsofstability,theydoaffectthefree-to-trtitrack.Thecenter-of-gravitylocationusedinallsubseq~enttests-1.50inchesforwardofthestepand6.50inchesabovetheforebodykeel-gavea free-to-trimtrackwhichwasabovethelowerandbelowtheuppertrimlimitsofstabilityforthetwoextrememodelsinvestigated.

GeneralTestData

Thedataobtainedfromthetestsofallhullsinvestigatedaregivenincollapsedformonsummarycharts(figs.15to 35). Thisformofpresentation,develo~dbyLocke(seereference5),enablestheresultsofresistance,spray,andporpoisingtestsforanyonemodeltobe pre-sentedona singlesummarychartwhichisdividedintothreepartsandshows:

(1) At thetop- iltiensionsofthesprayblisterenvelopesforfree- .to-trimtestsat displacementspeeds,inaccordancewiththemethodofpresentationdevelopedinreference4.

—.—.—c — — ——

.

13

.

NACATN 2503

(2)Intheat displacement

middle- resistanceandtrim&mgleforfree-to-trimtestsspeeds,inaccordancewiththemethodofpresentation.

developedinreference-3.A curveisshownforeach CA,-sincenobasis

hasbeenfoundforcollapsingthetrimtracksinthisspeedrange.

(3)At thebottom- resistanceandstabilitycharacteristicsatplaningspeeds,inaccordancewiththemethodsofpresentationdevelopedinreferences2 and3. Thecurvesrepresentthedataforallvaluesof CA andtrimcoveredby thetests.

Thesummrychartscanbe usedtomakeeitherspecificorgeneralcomparisonsusingthemethodoutlinedinreference12.

StaticProperties

Thetrtianglesandloadingswiththemodels

thedraftatthemainstepobtainedatvmiouEatrestir’thetankaregiveninfigures36

and37. Thecenter-of-gravitylocationusedinthesetestswasthesaneasthatusedthroughouttheentireinvestigation.Staticpropertiesofallhullcombinationswerenotobtained,butthosethathavebeenobtainedrepresentthemoreimportanthullcombinations.

eachhull

IandingTestData

Specificlandingtestsweretobemadeonthreehulls- oneforafterbodylength.Unfortunately,itwasimpossibletotestthewiththelongestafterbodylengthwithouta costlyrevisionofthe

apparatus.%e othermodelsweretestedatvariousdepthsof step,andtheresults,whichareintheformof chartsofnumberof skipsagainsttrimangleat contact,aregiveninfigures38and39. Thevariationoftrimanglewithspeedusedinthelandingtestsisgiveninfigure13.

Hull-ModificationTestData

Thevarioushullmodificationsweremadeto showtheimprovementsthatcouldbe gainedby refiningthehulllines.Sincethemodificationswouldnotchangeallthehydrodynamiccharacteristics,themodifiedhullsweretestedonlyforthosecharacteristicswherechangescouldbeanticipated.Thedataobtainedfromthetestsofthemodifiedhullsaregivenincollapsedformonsummarycharts,figures40 to43. Fig-urek-kshowstheinfluenceof stepdepthontheskippingcharacteristicsofthehullwiththewarpedafterbody.

-—. __.—._— _ .—— . .——-

14 NACATN 2503

.

Afterbody-RoachProfileMeasurements

Witha boom-supportedtailassemblyitis importantthatthetailclear&e afterbodyroachoccurringat speedsjustbelowthehunp.Afterbody-roachprofiles-fortheshort-d mediumafterbodylengthmegiveninfigures45,46, - ‘–and4(.

Ati-DragTests

modelswasdeterminedwiththemodelinair,watersfiface,andrunata numberofspeedsTWOmodelswitha 6.00-inchbeam- onewith

Theah dragofthesupportedjustabovetheandvarioustrtiangles.a shortafterbodyanda & sternpostangle,theotherwitha longafter-0bodyanda 10°sternpostangle- wereusedinthesetests.TheaveragedragcoefficientCD wasfoundtobe substantiallyindependentofmodel,speed,andtrimsngleandtohavea valueofofthiscoefficientcanbe explainedonlybyhadanopendeck.It isofsimilarordertobeentestedinthistank.

Ibw-SprayTests

about0.80.Thehighvaluethefactthatthemodelmanyothermodelsthathave

.

.

A fewrough-watertestsweremadeonthebasichull(modelno.1024-01)andtheh~l withincreasedforebodywarping(modelno.1222-01)atspeedsrangingfrom4 to‘1Ofeetpergecond(Cv= 1.0to 2.5)withaloadof5.45poundE(CA= 0.70)inwaves3 by 60 inches(2by 40 feetfullscale)and4.5by 90 inches(3by60 feetfullscale).Theresults,whichme basedonvisualobse~tio~j me givenbelow:

WavesizeModelno.

3 in.highby60 ti.long 4.5h. highbySQ in.long

Slightsprayoverbow Muchsprayoverbow1024-01 at 6 ft/sec; aboveand from8 to 10ft/sec

(basichull) belowthisspeedbowclear

1222-01 Slightsprayoverbow Muchsprayoverbow

(incryea:rebody at 6 ft/sec; aboveand at 7 ft/see,dimin-belowthiss~ed bow ishinguntilbowiSclear clearat 10ft/sec

Therewasa slightimprovementinthebowspraywithincreasedforebodywarping.

.

.- . — -—

.

.

NACATN 2503

ANALYSISANDDISCUSSION

15

ResistanceandMain-SprayTests

To selectthebestbeamandsternpostanglefora givenlengthofafterbodyonthebasisofresistanceandmain-spraycharacteristicsrequiresmeansformakingcomparisonsofthevarioushulls.A comparisonbetweendiffefenthulls,however,isnoteasytomake,sinceno nondimen-sionalformofpresentingtestdatahasyetbeendevised‘torepresentsatisfactorilythetransitionbetweenthedisplacementandplaningstages.Evenifthisproblemweresolved,a directcomparisonwouldbe possibleonlyifonecurvewereto lieaboveanotherthroughouttheentirespeedrange.

Itmightbe imaginedthata satisfactorycriterionforcomparisonwouldbe theresistancewhenthemodelcarriesa definiteloadat adefinitespeed.However,a difficultyarisesh thismethod.If,fora givenvariationof loadwithspeed,thebeamofthehullisalteredwhilethelengthisheldconstant,thewaterresistancealsochanges.l?hisisshowninfigures48 to54,wheretithespecificresistancecharacteristicsareworkedoutfora largenumberofcasesforonetake-offspeedandoneweight.Innearlyallofthecasesitwillbe seenthatasthebeamisdecreasedthehumpresistanceticreaseswhilethe ~resistanceathighspeeddecreases.Thisisinagreementwithpreviousinvestigations(see,e.g.jreferences13and14).

Noweventhesechartscannotbe useddirectlyto determinetheoptimumconfigurationbecauseoftheinterrelatedeffectsoftheavail-ablemarginofthrustatthemainhumpandatthesecondhmnpnearget-awayspeed.Thus,ingeneral,a largeexcessthrustanda hightake-offspeedfavora narrowhull. Therearel.tiitationsjhowever,onhownarrowa hullcanbemade,sinceoverloadinga hullcausesittothrowupa largesprayblisterat lowspeeds.Figure55illustratesthis,foritshowsthatthesprayheightsincreasewithdecreaseinbeam.

Inviewoftheaboveconsiderations,itwasapparentthattake-offcalculationsunderspecifieddesignconditionswouldaffordtheonesuremeansofassessingthemeritsofthevarioushulls.Calculationswerethereforeundertaken,withthefollowingfull-scalefactorstakenasbeingcommontoall:

Grossweight,pounds. . . . . . . . . . . . . . . . . . . . . . .3000Take-offspeed,milesperhour . . . . .,. . . . . . . . 60,68.7,77.4Wingloading,poun& persquarefootofwingarea. . .11.03,14.5,18.4Take-offliftcoefficient

()CL . . . . . . . . . . . . . . .. . . 1.2

Theobjectiveofthetake-offcalculationsisto enabletheselectionofthebestbeamandsternpostanglefora givenlen@hofafterbody.Forthiscomparisontobe effective,thespraycharacteristicsofall

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

16 NACATM 2503

hullswitha givenafterbodylengthshouldbe a~roximatelythesame.Thiscanbe accomplishedby selectingthedisplacementforeachofthemodelhullsona constantforebodyplan-formareabasis,as originallysuggestedinreference15. Thedisplacementsforcmstantforebodyplan-formareaandthecorrespondingscaleofmodelsaregivenintheaccompanyingtable:

(:.)5.25

6.00

6.75

Model

(5.) (?b)

19.50 4.80

19.50 5.86

19.50 6.99

Scale

m

8.55 3.74 13.89 52

8.00 4.00 13.00 52

7.54 4.24 1?.25 52

.

Severalsimplifyingassumptionsweremadetoreducethelabortivolvedinthecalculations.Themosttiportantwasthattheliftwasnota functionoftrfiangle,whichpermittedtheuseofa parabolicunloadingcurve.Theairdragoftheairplanewasnotincludedinthetotalresistance,and,inaneffortto compemateforthis)no correctionwasmadetothemodelfrictionalresistance.

Inthecalculations,thehullsweretrimmedtothezerc-momenttrimtrackupto justbeyondthehmp speed.Fromhumpspeedto get-away,thetrimtrackselectedwasa smoothtransitionfromthefree-to-trimtracktothetrimforminimumresistanceat ~ percentof get-awayspeed.

,Thethrustcurvesusedinobtainingthetake-offttiesarethe

ssmeasthoseusedanddiscussedlateron inthereport.Chartsofthevariationofresistancewithspeedforthemiddletake-offspeed(68.7mph)me givenh figures56to 58.

Theheightofsprayatthreelongitudinallocationsalongthehulls-6 feetforw~aofthestep,atthestep,and6 feetbehindthestep-forthemiddletake-offspeedisgiveninfigure59. ThisCOllS_hIl_bforebodyplan-formareacomparisonshowssomevariationsinsprayheightasthebeamischangedwithinanafterbodylengthgroup.Thevariationofsprayheightis,however,muchlessthanthatobtainedona constantloadbasis,as showninfigure55.

.

‘.

-—-——— -z_———.-

3

..

run m 2503

Thetake-offtimesgiveninfigure60. Ittimesareonlyrelative

17

(fullscale) obtainedfrcmthe-calculationsareshouldbeborneinmindthatthesetake-offbecauseoftheaforementionedshortcutstalqm

in makingthecalculations.Thetake-off-timecomparisonshowsthat,-:.forhullswiththeshortafterbody,theoptimwnbeammaybe somewhat. ‘greaterthanthewidestbeaminvestigated,andtheoptinnmsternpostangleappearstobe about& orpossiblya littlelower.Forhullswiththemediumafterbody,theopttiwnbeamis4.0feet,andtheopti-mumsternpostangleisabout80. Forhullswiththelongafterbody,theoptimunbeamagainis4.0feet,andatthisbeamthereis“verylittledifferenceintake-offtimewithchangeinsternpostangle,althoughthehighersternpostanglesshowa slightadvantageasthe“take-offspeedisincreased.

Themain-spraycomparisonforthetake-offspeedhour,figure’59,givesaboutthesameresultsas doescomparison.

of68.7milesperthetake-off-time

Onthebasisoftake-offtimesandsprayheights,thebestbeamandsternpostangleforeachlengthofafterbodywereselectedforfurthertesting.‘Thebeamselectedforallthreeafterbodylengthswasthemiddle,or4.O-foot,beam. Thesternpostanglesselectedwere6° fortheshortafterbody,8°forthemiddleafterbody,and10°forthelongafterbody.The10°sternpostangleforthelongafter-bodywasdeemedbest,sinceatthissternpostangleresistancesarenotonlyloweratbesttrimbutareattrhs abovebesttrim,asshowninfigure61.

LandingTests

thehigh-speedconsiderablylower

Afterthebestbesmandsternpostangleforeachofthethreeafterbodylengthswereselectedonthebasisofresistanceandspray,twoofthesethreemodelswerefurtherinvestigatedforlandingandporpoisingcharacteristics.Thek-inchfull-scaledepthof stepusedinthisseriesw selected,as discmsedearlierinthti-report,toavoidinstabilityonwaterlandings.The,resultsofthelandingtests(figs.38and39)giveno indicationofskippingatthedesignstepdepthof 4 inches(8.3percentofthebesm).Theparenthulldidencountersomeskippingon lanolinwhen@e stepdepthwasreducedto

72 inches(4.2percentofthebeam, as showninfi~e 39. me ~d~gtestsindicated,therefore,thatthedesignstepdepth.shouldnotbealteredwiththebasicafterbody.

,, ,.,.

,,’ .,.,, :-.. ,, ,..1,... .,,~,.rG..” .’-, }(,-:‘if

-.. ..—__ ___ _____ _____ ___ —. —-. . ..—

NACATN 2503,,

Full-ScaleResistancesandTdse-OffTimes.

Tomakethestudymorecomplete,andto illustratethemoredetailedapplicationofmodeldata,theresultsoftheresistancetestsforthethreehullshavebeenexpandedto fullscale.Thefollowingconditionswereassumedforadditionalcalculations:

Hull1 Hull2 Hull3

Grossweight,lb 3000 3000 3000

Take-offspeed,mph 60 68.7 77.4

Wingarea,sq ft 272 207 163

Wtigloading,lb/sqft . 11.03 14.5 18.4

Aspectratio 6 7.89 10

Horsepower 185 215 245

.

Thebestthreemodelhullspreviouslydeterminedwereusedh thisstudy.Again,thefree-to-trimtrackwasfollowedto justbeyondhumpspeed.Fromhumpspeedto get-away,thetrimtrackfolloweda fairedcurvefromthefree-to-trimtracktothetrimforminimumresistanceat 90percentofget-awayspeed.Modelairdragsweresubtractedfromthemodelresistancedatato givehydrodynamicdrag.

Itwill‘berememberedthatintheseresistancetestsan effortwasmadeto insuretheexistenceofturbulenceintheboundarylayerbymeansofa struttowedaheadofthemodel.Thisresultsinsomewhathighermodelresistancesbutmakesitpossibleto correctthefrictionalresistancewhenexpandingfrommodelto fullscale.

Sincethefrictionalresistanceisa smallpartofthetotalhydro-dynamicresistanceat speedslowerthanhumpspeed,no correctionofthefrictionalresistancewasmadeinthisspeedrange,andthemodelresistancewasexpandedto fullscaleby multiplyingthemodelresis-tanceby thecubeofthescaleratio(seereference16). At speedsbeyondhmp speed,wherethefrictionalresistanceisa largepartofthetotalresistance,themodelresistanceswereexpandedto fullsizeby a method(seeappendixA) similartothatusedinexpandingsurface-shipmodeldata.Thismethodofexpansionis importantonlyinthe

.,

.

—- —. ———————

NACATN2503

regionofthesecondaryofthrust)whichOCCWS

L 19

8

peakofresistance(ormirdmumavailablemarginatapproximately90percentofget-away,andwhich

isassociatedwiththephenomenonoftenreferredto as “sticking.”Atthisparticul-pointofthespeedrange,allofthecorrectionscanhel-d togetherandapproximatedby usingtheratioofm@el to full-scaleexpansionof A2”80 insteadof X3 whichwouldresultiftheReynolds

Theexpandedthedrag

The

numbereffectwereheglected.

calculatedairdragoftheairplaneandhullwasaddedtothewaterresistances.Theairdragattake-offwascomputedfromcomponentscorrectedforchangeinangleandgroundeffect.

dragcoefficientsusedforthecomponentpartsoftheairplanearegivenk tableIIIandthecurvesofpoweravailableandpowerrequiredaregiveninfigure62. Fromthisinfozmationjthepropellercharacteristicswereselected(givenintableIII)andthethrustcurvescomputedby themethodsoutlined@ reference17.

Thetake-offtimesofeachofthethreehullswerecomputedforeachofthethreetake-offspeeds.Thecurvesofwaterresistanceplusairdragtogetherwiththethrust,curvesgiveninfigures63to 65wereusedto computethetake-offtimes.

.Thetake-offtimesofthehullsunderthevariousconditionsare

approximatelythesame.Thisshouldnotbe surprisingbecausethebestbeamandsternpostanglewereselectedforeachlen~hofafterbtiy.

Porpoisi&Tests

TheupperandlowertrimUmitsofstabilityforthethreehulls-eachof Herent afterbodylength. underthevarioustake-offconditionsaregiven~ figures66to 68. A comparisonofthesechartsshowsthatthestabletrimrangeticreaseswiththelengthoftheafterbody.

HullModifications

Theeffectofthespraystripsusedonthemodelscanbe seeninfigure69,wherea comparisonofthemain-sprayheightsoftheparentmodelwithandwithoutspraystripsisgiven.Thischartshowsthatthespraystripsareextremelyeffectiveinreducingtheheightofthe -mainspray.

. 5e effectofthespraystripsonthe~ow-sp’eedresistanceandtrimcharacteristicsisgiveninfigure70,wheretheresistancesandtrhs

-. .— .-. -. —- .. . . . . . ....— — -—-—— -——-— — .C .—— — ——-.. —

20 mm TN 2503

oftheparentmodelwith.andwithoutspraystripsarecompared.Thespraystripsgenerallyincreasethetrima littleandreducetheresis-tancea littleatthehmnp.

Althoughtheuseof concaveforebodysectionsins%eadofstraightforebodysectionsiseffectiveinreducingthesprayheights,it isnotquitesoeffectiveastheuseofspraystrips(seefig.69). ‘l’heresis-tancesandtrimanglesoftheconcave-forebodymodelareslightlylowerthanthoseoftheparenthull,as showninfigure71.

Increasingtheforebodydead-risewarpinghasnegligibleeffectsonthemain-spraycharacteristics(seefig.69)andonthedisplacement-speed-rangeresistanceandtrimcharacteristics(seefig.71). Thelowertrtiltiitofstabilityofthehullwithincreasedforebodydead-risewarpingisonlyslightlylowerthanthatoftheparenthullat thelowerspeeds,andslightlyhigherat speedsneartake-off,as showninfigure72. Sincethemodelwiththeincreasedforebodydead-risewarpingwasidenticaltotheparentmodelfora beamlengthforwardofthestep(seefig.1),itisnotsurprisingthatthereareonlysmalldifferences ,.inthelowertrimlimitsof stabilityatthehigherspeeds.Increasingtheforebodydead-risewarping5mprovesthebowsprayslightly.

Warpingtheafterbodydeadrisedecreasesthehigh-speedresistancesappreciably,as showninfigure73,eventhoughthesternpostangleof

thewarpedafterbodyhullhadtbbe ~“ lowert- mat oftheparentmodel

inorderto obtainthesamehmp trtiastheparenthull. Warpingtheafterbodyenablesthestepdepthtoh reducedfrom8.3percentofbeam(4in.,fullsize)to at”least~.2 percentofbeam(2in.)withoutencoun-teringskipptigon landing(seefig.74). .

Ingeneral,themodificationsimprovethehydrodynamiccharacter-isticsofthe parenthull. Warpingthe-afterbodywouldpermita lowerdepthofstepandconcaveforebodysectionswouldpermita reductioninspray-stripsize.Theseimprovements,however,arenot~eat andwouldprobablynotbe justifiedsincethecomplicationofthehulllineswouldentailincreasedcosts.

PhysicalPictureofTwo-StepPlanti’g,.

Intheregion-ofthehumpspeed,a flying-boathullplanesonboththeforebodybottomandtheafterb-odybottom.It isbelieved@structiveto constructa physicalpictureofthisphenomenonandoftheforcesandmomentsinvolvedintheprocess.Forthispurpose,underwaterphoto- .graphsoftheparenthull-withoutspraystripsweretakento showthe.,.. ...

.

-—— .

NACATN 2503 a

forebodyandafterbodywettedareas.Onesuchphotographisshowninfigure75,togetherwiththeforcesresultingfromthesewettedareasas estimatedby themethodsgiveninreference18. A forcediagram,togetherwithcalculationsoftheforebodyandafterbodyhydrodynamicpitchingmoments,isgiveninfigure76.

An understandingofthephysicalpictureoftwo-stepplaningh thevicinityofthehmnpwasutilizedindesigningtheparenthulloftheseries.Priortotheactuallayoutofthehulllines,valuesofhumpspeed,hmnptrim,andwater-borneloadathmp speedwereassignedforthebasichullonthebasisofprevious’experience.Bymeansofthemethodsgiveninreference18,theforebodywettedlengthwasestimated;this,inturn,enabledan est~tion ofthecenterofpressureandofthepitchingmomentdueto theresultanthydrodynamicforceonthefore-bodytobemade.

Therequiredmomentgeneratedby theafterbodymustbalancethe’momentproducedby theforebody.To determinethemomentproducedbytheafterbody,thewaveprofileh thewakeoftheforebodywasplotted.A locationof-theafterbodywaschosenby trialanderrorresultingpositionofthecenterofpressure- determinedlengthoftheafterbody-’producedthemomentrequiredtoduetothehydrodynamicforceactingontheforebody.Inthesternpostanglewasdetermined.

so that thefromthewettedbalancethatthismanner,

Inordertousetheinformationgiveninreference18,itisneces-saryto knowthehup trimandthespeedatwhichitoccurs.Thepre-dictionofhmnptrtiisnoteasyandto titeisbasedonpreviousmodeltests.Inorderto calculatethehmp trti,a relationshipbetweenthesternpostangle,theratioofafterhodylengthtobeam,andtheloadcoefficienthastobe detemntied.Forthepresentseries,an empiricalrelationshipbetweentBesequantitiesisgivenby thefollowing-

T()

6 2CAathmp, calculated= -0.8+ 1.2a+ —&/b

A comparisonofthemeasuredhumptr~ andthecalculatedhmpisgiveninfigure77.

equation:

trims

Similsrly,thespeedatwhichthehumptrimoccurscanbe calculatedfromanempiricalrelationshipbetweentheratioofafterbodylengthtobeamandthesternpostangleas follows:

% athwp trim,calctited ()= 1.14+0.60 ~ -o.023(u- 7.5)2

#

22

A comparisonofthemeasuredcalculatedspeedcoefficient

rumTN2503.

speedcoefficientathmp trimandtheathumptrimisgiveninfigure78.

CONCLUSIONS

Thefollowingconclusionswerereachedfromthehydrodynamicinvesti-gationofa seriesofhullmodelssuitableforsmallflytigboatsand-phibians:

1. It ispossibleto desigua hullwithsimplifiedlinessuitableforsmallflyingboatsoram@ibians.

2.Refinementsinthehulllinessuchas concaveforebodysections,ticreasedforebodydead-risewarping,andafterbodydead-risewarpingimprovethehydrodynamiccharacteristics,butthegainsmaynotbeworththeadditionalconstructioncostinpersonal-owner-zypeflyingboats.

3.Thebeamandsternpost&gle selectedto givethebestsprayandresistancecharacteristicsfora particularlengthofhullalsogivesatisfactorylandingandporpoisingcharacteristics.

4.Comparisonofhullsofthesamelength,butv~g beam)Onaco~tant-loadbasisshowsyingeneral)thatthe~OW h~~ havel-essresistance,beingbetterinthedisplacementandplaningspeedranges,thoughworseinthevicinityofhumpspeed.Thenarrowerhulls~ however,aremoredeeplyimmersedandconsequentlythrowmorespray.

5. ComparisonofthesehulM ona basisof constantforebodyplan-formareashows,ingeneral,littlevar~tion~ sPraYheightwithbe~~b thistypeofconq=tion,m rownessmustbe accompaniedby increasedlensrthifhullsofdifferentlength-beamratioareto”carrythesame10Z. Theincreasedofthe~W hull.

StevensInstituteofHoboken,N. J.,

lengthpart~ll.yoffsetstheadmtage h resistance

TechnologyDecember29,1949

-——.

mm TN2503

,-

23

APPENDIXA

EXPANSIONOFMODELRESISTANCEDATA

Ithasbeenlmownformanyyearsthatflying-boat-hullmodelresis-tanceissubjectto scaleeffect.Thescaleeffectistheresultofdifferencesinthemodelandfull-scalefrictionalresistancecoefficientscausedby thedifferentmodelandfull-scaleReynoldsnumberswhenmodelandprototypearerunatequalFroudenumbers.Theproblemhasbeencomplicatedby thelackofknowledgeof full-scaleroughnessresistance.Inthepast,ithasbeenthepractice,wheneverpracticable,to comparetheresistanceofmodelsof equalsize,therebycancelingscaleeffects.Forfull-sizepredictions,resistancewasexpandedby thecubeofthescaleratio,reliancebeingplacedon largemodelsto reducescaleeffect. Itwastacitlyassumedthattheincreasedroughnessdragofthefull-sizeflyingloatwould-compensateforthedecreasedfrictionalresistance.As thescaleratiobecmne~eaterbecauseoftheticreasedsizeof flyingboatsandbecauseoftheuseof smallermodels,itbecameapparentthatthisassumptionwastooconservative.Theneedforamodel-to-full-scaleresistanceexpansionshnilartothatusedinsurface-

. shipresistancetestingthusbecameapparent.No standardprocedureforexpansionofflying-boatmodelresistance,however,hasachievedwideacceptancebecauseofthelackofknowledgeconcerningfull-scalerough-nessresistanceandthemanyarithmeticaldifficultiesinthecomputation.

Theprocedureforexpansionofmodeltestdatato fullsize(refer-ence19),widelyusedinsurface-shipresistancetesting,utilizestheSchoenherrfrictionformulation.A stiilarmethodusedinC&manyinmodel-seaplaneresistancetestingisgiveninreference20. I!Qthoftheseprocedures,however,requirewetted-areameasurementswhicharenotoftenrecordedh seaplanetests.Themethodsuggestedinthisappendixissimplerthanthosegiveninreferences19or20 hasmuchaswetted-areameasurementsarenotneeded.

TheSchoenherrfrictionformula,whichisofanawkwardform,canbe approxhnatedby an exponentialformulaforanyparticulararrangementofReynoldsnumbersdesired.Inparticular,iftheReynoldsnumberdoesnote~ceedabout2 X 107,thewell-knownformulaofPrandtlandvonKarm& canbe used.Thisformulaforthecoefficientof frictionalresistanceCf is:

Cf= 0.074(Re)-0”2

fromreference21wheretheReynoldsnumberRe isequalto YG/v.

24 NACATN 2503T

Formodeltestssuchasthese,wheretheFroudenumbersofmodelandfull-scaleareequal,thefollowingrelationshipsexist:

linearscaleratio,fullscalemode1

@/2 speedscaleratio

At equalFroudenumbers,thetrimanglesofmo&l andfull-sizehullsareequal,thewaveformationofthemodelisidenticaltothatoftheprototype,andthedistributionofwettedareasisthesame.Thefric-tionalresistanceisthereforeproportionaltothefrictional-resistancecoefficient.Usi.ngtheexponentid formofexpressionforthefrictional-resistancecoefficientgivesthefollowingequationforthecorrectionfactor,wheresubscriptsm and s areusedto denotemodelandfullscale,respectively:

Theconversionofmodel frictionalresistanceto full-sizefrictionalresistanceisthen

= ‘fmL2”7Thehydrodynamicresistanceisconsideredtobe composedofthe

resistancecomponentoftheforcenormalto theplantigbottomandthefrictionalforcetangentialtotheplaningbottom.mis frictional forceincludesthatoftheafterbodyaswellasthatoftheforebody.Thellft

.

— ———— —

.

4 NACATN 2503 25

.-

.

forceoftheafterbody,ifanyexists,isneglected.Trimisheredefinedasthetruemeaninclinationoftheplaningareaandnotaea’nominalfigurereferredtoanarbitraryreferenceltie.Thus,incom-putingfull-scaleresistances,thefollowingstepsweretaken:

(1)

(2)

(3)

(4)

The

Totalmodelwaterresistance= Modeldynamicresistance+ modelfrictionalresistance(wheremodeldynamicresistance= & tanT)

ModeldynamicresiatanceX X3 = Full-scaledynamicresistance

2“7 = Full-scalefrictionalModelfrictionalresistanceX hresistance

Totalfull-scalewaterresistance= Item(2)+ item(3)

abovemethodofexpansionwasusedinthespeedrangefrom60percentof get-awayto get-away,wherethefrictionalresistanceisa largepartofthetotalresistance.Whentheseresistancesareplottedagainstspeed,theresultingcurveisstiilartoThelow-speedendofthiscurveisjoinedtothezerotohmp speed,labeledB infigure79,by a

curveA infigure79.resistancecurvefromsmoothcurvelabeledC.

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

26 NACATN 2503

APPENDIXB

COMPARISONOFNACA40BEDESIGNANDE.T.T.MODELNO.1057

INTRODUCTION

Theseriesofhullsdescribedinthebodyofthisreportwasdesignedonthebasisofpresent-dayhydrodynamicknowledgeandwastestedforlongitudinalstabilityandma3n-spraycharacteristicsaswellas forresistancecharacteristics.Thelastcomprehensiveworkon smallflyingboatswasthatundertakenby theNACAh 1934onthemodel40 seriesinwhichtheonlycharacteristicoftheabovethreeinvestigatedwastheresistance.Sticethepresentstudycanbe consideredtobe a continuationofthemodel40 seriesstudy,itwasthoughtdesirabletomakea compari-sonofthelongitudinalstability,spray,andresistancecharacteristicsofthetwohullseries.~ order.todoso,oneofthedesignsinthemodel40serieswasbuilttothesamebeamas themodelsintheE.T.T. series,andtestedinthesame~er.

Thisappendixpresentsa comparisonoftheresistace,matispray,andlongitudinalstabilitycharacteristicsbetweentwomodels- oneineachseries- thathaveapproximatelythesamehullproportions.

MODELS

ThedesignselectedfromtheNACAmodel40 serieswasmodel40EE.Thisdesign,builtto a 6-inchbeam,isdesignatedmodelno.1290-01.Modelno.1057-04(havinga sternpostangleof9°)wasselectedfromtheE.T.T.series.

Thesetwodesignshadpracticallythesameratiosof forebodyandafterbodylengthtobeam,andtheste~post~gle ofthemodelselectedfromtheE.T.T.serieswastakentobe thesameas thatofthe&OEEmodel.

Thecenter-of-gravitylocationsforthetwomodelswereslightlydifferent,as canbe seenfromthefollowingtable:

Modelno.

1057-04(E.T.T.)

12go-ol(NACA40BE)

Centerofgravityabove Centerof gravityforwardforebodyload, ofstep,

(in.) (in.)6.50 1.50

7.18 L 85“

.—.-.—. —

.

rumm 25a3 27

Modelno.1290-01wassetupwiththesamec~nter-of-gravitylocationashadbeenusedh theesrlierNACAtests,whilemodelno.1057-04hadthesamecenter-of-gravitylocationusedforallnodelsintheE.T.T.series.

ThepertinentparticularsofbothmodelsaregivenintableIV,andthehulllinesarepresentedin

ThedataobtainedfromthehOBEdesign- modelno.12~-01

figure80.

RESULTS

testsonthe6-inch-beammodelofthearepresentedincollapsedformona

summarychartin figure81. Thedataforthecorrespond-tigdesignintheE.T.T.series- modelno.1057-04”- wereobtainedby interpolationfromthedataobtainedonmodelsnos.1057-01and1057-03,whicharepresentedinsummary-chartforminfigures25and22,respectively.

Specificcomparisonsofthetwodesignswereobtainedfromsummarychartsby usingtheload-fall-offcurvegiveninfigure

ANALYSISANDDISCUSSION

Thetwodesignswerecomparedon thebasisofa full-scale

the82.

QCOBEweightof 3000poundsanda t&-off speedof 68.7milesperhour. Asinthebodyofthereport,themodelresistanceswereexpandedto fullscaleby themethod.outlinedh appendixA.

Thelongitudinalstabilitycharacteristicsofthe@l%!design(modelno.1290-01)arepresentedinfigure83,whichshowsthreetrimtrackslabeledA, B,andC. TrimtrackA isthatforbesttrtiandisbasedontheNACAdatareportedinreference1. TrimtrackB isthe

(free-to-trimtrackCM .

)0.0 asobtainedintheporpoisingtestsof

modelno.1290-01.TrtitrackC followsa fairedcurvefromthefree-to-trtitrackinthevicinityofthehunptowardthetrimforminimumresistanceat 90percentof get-awayspeedbutrisesatthehigh-speedendtoavoidthelowertrimlimitof stability.

A comparisonofthelongitudinalstabilitycharacteristicsofbothdesignsispresentedinfigure~. Thetrimtrackshownh thisfigureformodelno.12g0-01isthesameasthatlabeledC infigure83. Thetrtitrackformodelno.1057-04follows,fromhumpspeedto get-away,a fairedcurvefromthefree-to-trimtracktothetrimforminimumresistanceat 90percentof get-awayspeed.

—.. ..—---- .- .- ..__ —.—. — -.. ~—. — _____ —._

28

thanThelowertrimlimitofstabilitythatforthe40EEdesign,andthe

NACATN 2503

formodelno.1057-04isloweruppertrimlimitofstability

formodelno.1057-04ishi&er thanthat-forthe40BEdesign.The-spreadbetweentheupperandlowertrimlimitsof stabilityat50miles

10formode1 no.1057-04andisonly4° forperhourisapproximatley~

the40BEdesign.Thisincreaseintherangeofstabletrimscanbeaccountedforby thedifferencesinthedesignofthetwohulls.

Previousinvestigations,reportedin‘references11and22,haveindicatedthatwarpingoftheforebodybottomof flyingboatsloweredthelowertrtiltiitof stability.Thewarpingoftheforebodybottomwasaccomplishedbymaintatiingthesamekeelprofileandincreasingthedead-riseangles.Thismethodisapproximatelyequivalentto anupwardrotationoftheoriginalbottomwithrespecttothedesignrefer-enceltie.Consequently,anymodificationwhichisequivalenttoanupwardrotationoftheoriginalbottomwithrespecttothedesignrefer-encelineshouldlowerthelowertrimlimitwhenthetrhnanglesarereferredtotheoriginaldesignreferenceline.

Oneofthedifferencesbetweenmodelno.1057-04andthe40EEdesignisthehigherprofileofthel/4-beamwidthsformodelno.1057-04,asshowninfigure85. Thisdifferenceisapproxhnatelyequivalentto anupwardrotationofthe40BEdesignwithrespectto thedesignreferenceline.Sincethedesignreferencelineisthesameforbothhulls,thelowertrimlimitof stabilityshouldhe lowerfortheupward-rotatedforebody,namelythatofmodelno.1057-04.

Thehigheruppertrimlimitofstabilityofmodelno.1057-04is .primarilyduetotheincreaseddepthofstep;modelno.1057-04hasmorethantwicethestepdepthofmodelno.1290-01.

Theresistancesofthetwomodelsarecomparedinfigure86. Thetrimtracksuptohumpspeedarethezero-momenttrimtracks.Thedifferencesinthezero-momenttrimtracksareprimarilyduetothedifferenceincenter-of-gravitylocation.Fromhumpspeedto get-awayspeed,thetrimtracksarethoseshowninfigure84.

Modelno.1057-04hashigherresistancesthanmodelno.1290-01Mthevicinityofthehump,butlowerresistancesathigherspeeds.Thetake-offtimesfora 68.7-mile-per-hourtake-offspbedarethesameforbothmodels.Athighertake-offspeeds,modelno.1057-04hassomewhatlowertake-offitiesjwhileat”.lowertake-offspeeds,modelno.1290-01hassomewhatlowertake-offtimes.

NACA

can

TN 25.03 29

Thesprayheightsofthetwomodelsarecomparedh figure87. Itbe seenfromthiscomparisonthatmodelno.1290-01hasslightly

lowerspraythanmodelno.1057-04.Thisisprobablyduetothefactthatthespraystripsusedonmodelno.1.290-01increasethebeam,andhencetheloadperunitareaofwettedbottomissomewhatlessthanthatofmodeln:.1057-04.

CONCLUDIIJG~

TheE.T.T.design(modelno.1057-04) has

.

a greaterrangeofstabletrims,lowerhigh-speedresistances,andprobablybetterlandingstabilitythantheNACA@lE design(modelno.1290-01).TheNACA40BEdesignhaslowerlow-speedresistancesandsomewhatlowerspray.heights.

.

.

—.—. -— —— .——— —–.—— —–

30 NACATN 2503

REFEREWES

L Parkinson,JohnB.,andDawson,JolmR.: T- TestsOfN.A.C.&Model40SeriesofHullsforSmallFl@ng BoatsandAmphibians.NACARep.543,1936.

2.Locke,F. W. S.,Jr.: GeneralPorpoistigTestsofFlying-Boat-HullModels.NACAARR3117,1943.

3. Locke,F.W. S.,Jr.: GeneralResistanceTestson Ilying-BoatHullModels..NACAARR4B19,lW.

4.Locke,F.W. S.,Jr.: “General”Main-SprayTestsofFlying-BoatModelsintheDisplacementRange.NACAARR5A02,1945.

5. Locke,F.W. S.,Jr.: A CollectionoftheCollapsedResultsofGeneralTankTestsofMiscellaneousFlying-Eoat-HullModels.NACATN 1182,1947.

6. Lack, FredW. S.,Jr.: A CorrelationoftheDtiensions,Proportions,andLoadingsofExistingSeaplaneFloatsandFlying-BoatHulls.NACAARR,March1943.

7. Lock, F.W. S.,Jr.: AnAnalysisoftheSkippingCharacteristicsofSomeFull-SizeFlyingBoats.NACA~ 5J24,1946.

8. Olsen,RolandE.,andMd, No~ S.: EffectofAfterbo@~n@handKeelAngleonMinimunDepthofStepforLandingStabilityandonTake-OffStabilityofa FlyingBoat. NACA~ 1571,1948.

9. Fried,Walter:TheNo.3 TankforModelSeaplaneTests.Rep.No.289,Exp.TowingTank,StevensInst.Technolo~,Ott.1945.

10.Locke,F.W. S.,Jr.,andBott,HelenL.: A Methodfor~~gQuantitativeStudiesoftheMainSprayCharacteristicsofFlying-BoatHullModels.NACAARR3Kll,1943. .

11.Davidson,KennethS.M.,andLocke,F.W. S.,Jr.: SomeSystemticModelExperimentsonthePorpoistigCharacteristicsofFlying-BoatHulls. NACAARR3F12,1943.

12. Locke,F.W.S.,Jr.: A GraphicalMethodforInterpolarionofHydrodynamicCharacteristicsofSpecificFlyingBoatsfromCollapsedResultsofGeneralTestsofFlytig-Wat-HullModels.NACATN lZ?59,I1948.

..

.—

NACATN 2503 3i

.

.

13.

14.

15,

16.

17.

18.

19.

20.

21.

22.

23.

24.

25.

Clark,K.W., andCoombes,L.P.: TankTestsofa FamilyofFourHullsofVaryingLengthtoBeamRatio.Rep.No.BA 1350,BritishR.A.E.(Farnborough),Nov.1936.

Shoemaker,JamesM., andParkinson,JohnB.: TankTestsofFl@ng-BoatHulls.NACATN 491,1934.

Bell,JoeW.,Garrison,CharlieC., andZeck,Howard:Effectoflk@h-EeamRatioonResistanceandSprayofThreeModelsofFlying-BoatHulls.NACAARR3J23,1943.

Gruson,M. F.: EkbnilitudeinHydrodynamicTestsInvolvingPlaning.NACATM 795,~936.

Diehl,WalterS.: EngineeringAerodynamics.TheRonaldPressCo.(NewYork),1928.

lbrvin-~oukovsky,EorisV.,Savitsky,Daniel,andLehman,WilliamF.:WettedAreaandCenterofPressureofPlaningSurfaces.Rep.No.360,E@. TowtigTank,StevensInst.Technolo~,Aug.1949.PaperNo.244,ShermanM. FafichildPub.Fund,Inst.Aero.Sci.,Aug.1949.

Anon.: UniformProcedurefortheCalculationofFrictionalResis-tanceandtheExpansionofModelTestDatatoN1 Size.Bull.1-2,TheSoc.NavalArchitectsandM@ne Eng.,Aug.1948.

Sottorf,W.: NewMethodofExtrapolateionoftheResistanceofaModelPlaningB6attoFullSize. NACATM 1007,1942.

Rouse,Hunter:ElementaryMechanicsofFluids.JohnWiby & SonB,Inc., lg46.

Carter,ArthurW., andWeinstein,Irving:EffectofForebodyWarpontheHydrodynamicQualitiesofa HypotheticalFlyingBoatHavinga HullIength-I?eamRatioof 15. NACATN N328,1949.

Abbott,_ H.,VonDoenhoff,AlbertE.,andStivers,tiuisS.,Jr.:s~ ofAirfoilData. NACARep.824,1945. (FomerlyACRL~O~.)

Wood,K.D.: TechnicalAerodynamics.Seconded.,McGraw-HillBookco., Inc.,1947.

Hartman,EdwinP.,andBiermamn,David:TheAerodynamicCharac-teristicsofN1-Scale PropellersHaving2, 3,and4 BladesofClarkY andR.A.F. 6 AirfoilSections.NACARep.640,1938.

_-— — -----— ——

I

1

1’

I

I

ForebcdyAfterbodyBeemat step step 8ter7rgmt Tail Tail Tail TailHaua Lb8igmti0n I.mgth length step heightdDfUil?iBO en+ Imgth Bw

(a) (Q) (in, ) (in, ) (deg) (lied (rt) (ft) (Brf:) ;:Yot

Amphibian P-iZI-B 11.2.‘1 lW.4 x.7 2.4 7.0 32.8 17.55 9.8 3k.8 2.~

Bendix 71 140,3 144,4 @6 4.1 25.0 8.1 15.@ 8.9 36,4 2.18

Curtb+rigbt CA-1 129.O llklT w.k 3.7 19.0 8.7 12,~ 12.s ~.o >,OU

DO!l@aO Mlw 144,1 113,5 41.3 4.0 20.0 11.4 18. la IL2.7 40.0 4.03

Flee’w@ Bmabhd 1k6. 9 117.0 46.3 --- 19,3 ---- 16.10 1o.,130.0 3.41

Fokkar r-xl 174.8 D.8 3s.6 3.0 24.0 0.3 19.40 12.7 49.0 3.30

Goodymr OA-2 137.4 179,7 44.3 2.2 20.0 9.3 14.85 Il.1 31.4 3.93

&lmmeJl G21A IX.6 Krf.9 k3.3 2,4 25.0 8.5 1.2.~ 11.4 38.0 3.42

Grm Q-44A 139.0 55.6 44.5 2.9 20.0 8.7 14.E 11.9 34.6 4.10

Ke@xme Cmuter 151.2 34.0 4-4.4 --- 22.0 --– ----- IL 7 43.0 2.85

Fapublic 9eebaeR-3 130.8 U%.8 50:2 3.2 20.0 8.6 14.10 u..5 37.1 3.E16

sibx’e4 8-39 130.9 109.1 49.1 --- 22,s --- 15.63 14.7 40,0 5.26

Spencer-bnmnm-la 185.0 B.6 49.9 --- 15,0 — --— 13.9 33.8 5.72

A~ 140.7 I.u..8 47.2 3,2 19.8 .9.4 15.63 U_.8 36.9 3.77

186.0 159. -/ H 6 4.1 25.0 K2.8 19.* 14.5 L9.o 5.8)

u. 7 Ll+.o 41.T 2.2 7.0 8.1 12.p 8,9 27.0 2.18

(Aro

t

‘5

.

NACATN2503

TABLEII

PARTICULARSOFPARENTMODELNO.102~01

Item Fullscale ModelI

Bcale 1 1/8

DIMENSIONS

&am,rmxdmum,h.Beamatmainstep,in.Forehodylength,In.Afterbodylength,ti.~erbo~ angle,degStepheight,h.Bternpostangle,degLength-beamratioCenter-of-gravitylocationForwardofEtep,in.Aboveforebodykeel,in.

GroBsweight,~, lbSrof3~ loadcoefficient,c~ (fnsshwater)l?itchtigmomentOfWrtia, lbEq fi..wingBpan,ftWingincidencewithforebodykeel,d.egHorizontaltailarea,sqftraillength(c.g.to35-percentM.A.C.oftail),.f%

48.0047072156.00162.006.64.008.0.7.63

$::3000

“ 0.7531.245X10740.4

32:;

15.63

AERODYNAMICCHARACTERISTICS

6.005.9619.5020.256.60.508.07.63

1.506.505.860.7533e05.055.00.577

1.954

CLatT = @ (take-d’ftrim)

~L/dT (w@3),p-=@~~/dT (tail),perdegdM/d.q,lbft8ec~raddM/de,lbft/deg

1.2.0..0730.05030.7veo.0343V*2

L 20.0730.@o

7.53x 10-3Pm6.71X 10_5Pm:

Item

Speed

Length ‘AreavolumeMoment

MomentofInertia

Rat io of W-male dinensiolltomodeldmension

.

‘-.’. .. —-.. . . ..

33

_——. _____ ______ .._ . —— -- .—...——_. —— ___ .-._— _ _

TABLElm

DRAGCommcmt?m Am mm m PROPELLERoEAMmmmTIcs

PORBACH OF ITiE’EIREEWIl13AFlEMUSPDPORCCMPUC.U7G

FULLWALE FLI@T PEY9~E

Uing Nacelle Hull HullT.#m-off wing Tip CDO

!Me.1

area swed TailfI.oati %0 %0 Hull ‘% Aqx3ct

sq ft) (mph) c~o No bae~ baeed frontal bed ratio,

%be-ma

on wing, on wing on hull(y%)

on Vtig n

(1)am5a area frcaltil area

area (2)

2’+2 0;o12 00C@-9 0,Oolzl 0,W206 o.Ocg-12& .%;

22,0.034’0

0.I-2 O.of?m.0L2

6.00. Om.2 . C13326 , O= 22.0 .12

v. 4 .012 .W4a .-.03401

.00127.@

, o16m 22.0 .I.2 .03908 10.00

Engine R6pelhr ~3)W’i.ng

‘ area SwdBlade Power

(Eqft) (mph) Ikrdacturer number Power speed. Diameter angle(bhP) (J@

at uaxhum(ft) at 0.75R

(dog)@eil(thp)

272 135 Continantii 2-185-5 m 2300m

7.5 18149

lbgPranklin QIM1.$m 21.5 7.5 18

163 16$In

Frankl.in 245 * 8.0 22 207

%ng eection W en lW!A 2415 rod ad an ItACAk@ tip (.eereference23). =@=

%tal.~-TotalC~+~where ~ L91.Mtcoefflclerrtandn w effective

=Peti ~tti (reference17). 2ymb01 n in taken here ma equl to mpect ratio, spn2/vbg area,

he reference.24 and 23.

t

NACATN 2503 35

.TABLEIV

PARTICULARSCIFMODELNO.1~-okA19DMm NO.1290-01

Moti-lno.1057-04Modelno.12~01Item E.T.T.design NACA40BEdesign

1/8scab ‘ 1/8’Bcab

DIMENSIONS

Beamatmainstep,in. :.:; 6.tiEeam,m., In.Beam,max.overspraystrips,in. 6:0 .2:$Forebodylength,in. 19.50 19.38AfterEo@length,h 27.00 26.77Afterbodyangle,deg 8.0 8.5SternPostangle,deg 9.0 .9.0Stepheight,in. 0.50 0.23Length-beamratio 7.75, 7.69Center-of-gravitylocationForwardOfStep,in. 1.50 -Aboveforebodykeel,in. 6.50 ;:!?!

Groa8weight,~, lb 5.86GroOsloadcoefficient,C~ (freshwater) 0.753Pitchingmamentofinertia,lbin.2 3&)WlrlgSpan,ft 5.05Wingincidencewithforebodykeel,deg 5.0Horizontaltailarea,sqf-t 0.577Taillength(c.g.to350percentM.A.C.oftail),f-t 1.9%

Aerodynamiccharactertitics

CLatT = 60 (take-ofl trim) 1.2~~dT (wing), p3rdeg .073~~dT (tail),perdeg .050 ‘dM/dq,lbf%sec/r&d 7.53x lo+ ,“dM/de,lbft/deg 6.~ X l@v~2

Item Hatioofflill-Elcaledimemhltomo*l*nsion

Speed ~1/2 = 2.81Length ?.; 8.00Area X2= 6.40X 1~Volume X3=5.U2X102 , -Moment X4= 4.096x 103 “

MomentofInertia “ ,~5=3.277xlo4— — .

NACATN 250336

80I I I I I I I I I I I

60

40

20

0

60

40

20

o’

FOREBODYDEADRISEDISTRIBUTION

‘\\.

:\

a ‘\\ MODEL NO.. \ 4$?22-01

8 \

E\ %.

2w ‘\\n \ .\+

MODELNO.102401~(PARENT)

o 50 100BOW PERCENTOF FOREBODYLENGTH STEP

I I I I IAFTERBODYDEADRISEDISTRIBUTION

,.

gMODELNO.

w“ -- --- .- -1221-01-e-” “u) -.E ---

●- -++.

2 04- -

u / -\a

MODELNO. 1024-01- ~(PARENT)

,.=s=

.:

0 -. 50 ‘. . 100

STEP ‘ :. PERCENTOF AFTERBDDYLENGTH STERNPOST .

Fi~e 1.-’%riationofdeadrisewithforebodyandafterbodylength.

.

Y

I

I

156”

~“ m‘“2” .CHINE, KEEL INTERSECTION

b D 34”

Xf /

./POINT “OF TANGEIWV ~

EQUATION OF KEEL CURVE:

W“+ (+)’”7’ ‘-’~ -

H’”+(a’””=‘ “m ‘c?.-Full-scale

I BA9Ekl NE

o

forebodykeel curveequation.

240” w

186” ~132” -

Lf~156” — — : La , 216” *

tY

a

(*Y”’+“(*Y”n=‘( SHORT AFTERBOOY) ( MEDIUM

WHERE PI s

I

P3 ‘

A%tWCOY) (LOW AHERDODYi

bMm/2(LO + 24”)2”76

x(La +24 )&”so

&$&ts

.,

Figure 3.- Dhensions and full-scaleplan-fonu curveequations.

.

I

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LJo”

SEUTION A-AhiODEL SUE

\

.-

. ,06” ‘A “ BARE HULLCHINE

*A 4.10”

.,

0 L25W MO”

.

Ax)” 7M” 10.00” 1s!.75”

I

iI

NOTES :DIMENSIO+tSARE IN mowzd FOR MOOEL.

DRAWING oNE-mLF mOOEL SIZE,

Figure4.-E.T.T. series. Spraystripusedl/32inch thickset flushwith

on furebodies;sideof hull.

2t--3“ .13”’

—

‘&m”-=s= ‘9’80”

spraystrip

1.

A5F

.

.

00”

woo”21.60”19,SO” AaF

I 1056-01

.44.00”

Fraoo”

.00”“

M.00*19.60”AaF

0s7-01

FUSFWXS.-E.T.T.seriesmodel hm MIIeS ~th ~

beam of 6.OO inches.

49.60”

us” &so” am” 7.s0” moo” m75”16.00” 19.s0” 2*00” 22.00” 5a.ds4.00= 59.76”

\— -

J01M7

\ “- , - \~ _ ST2RHPOET

~ .

f’ “

~ —

.

1086-01 1024-01 1057-01

,

M NACATN 2503

,

//

,ld+, \

41

//

14J?-01

)I

105s-41

%

I1044-04

I

14s7-42 I

\

A1SU,-MI

I I (1U4-U ) I /r’--A . d

oOthermmdelatented.

•1Nottested. .

Figure6.- E.T.T.series.

—..- . ... —.—. ——. ..— ——— .—— .—

iK

fomBm7 SPRAYSTRIP

,Be.oo”

,8P A8F

1054-01

“

.

‘ 1055-01

w%”&JJ& o.c&7JJ0”lo.oo= IR.7U” 15.00” 19.00” n.oo” two” Ba.o@Moo” 8a76” 4.5.809

\Jam

~ MERWPOS7\

~ -— . .

/ ~— —

.

lo64*l 045-01 1053-01

Figure 7.-E.T.T.seriesmodelhulllinestithmaximumbeamof5.25inches.

.

I

I

I

FOFEBODYSWY.16: BTRIP ,39.00”

.RN\ I, i.51”.\ 1 /, B>Yo”

m

“

.

.

‘AFhF

“

00”50”80”

‘ 1056-01

AMF

I 1059-()[

Em”280”Boo”mommoo” 1278” 15,00” mm” W.po=

-%

5TERNP05T

1068-01 1044-01 1059-01

-8.- E.T.T. -5es modelhull lineswith mdmum beam of 6.7.5 inches.

.

o.ea” ~

1220 ‘

1221

39.00”

i!iii!

34,00”29.00”

Z4.00”19.00”A

I

1221COMAVE FOFfSODY WARPED A~tXIY INOREASEDFU?EECOY WAIWING

0.63”1.25”

I 9,50” $?4.00” ?.8.00” i%oo” 30.00”79.75” CT 2.50”6.00” 7.30”10.00” 12.78” 15.mY 19.LIO’

=’ ‘k ‘ : ? L“”1 1 1 1 t 1

~

WARFED AF7EREODY INCRBSED KIREMJDV WARPINQ

Figure9.- E.T.T.serieshullalterations.~beam, 6.OOInches. !a

,

Figure10.-Appsxatusused in testsfor charaoteriBticsof spray, .residance, longitudinalstabU3.tyjand staticproperties.

46 NACATN 2503

.

.

Zo ‘ -

6.0

5.0

\ \

4.0

\

3.0 \

2.0

\

1.0 \

\-=s=

o0 10 20 30 40 50

SPEED, FT./SEC.

FigureI.J___E.T.T.seriesloadandspeedrangeformodeltests.

.

-.— —-— — ——______ .----- —..-

>

Figure12.-Appsxatusused in test for skLppingoharaotmzktics.

,.I

I

II

I

‘2FFF-‘“w--t--t

J \

\ \WING L0ADlN6 14.5 LB. SO. FT.

8 -j

z

6 -F

az

z WING LOADINGa

11 LB./SO. FT.

4 -J

2 \ I

=@=

n

50 60 70 60

Figure 13.- Landingtrim amd speedfor grossload of 3000 pounds(zeroglide-pathangle).

7,.

NACATN2503 kg

.

I MODEL NO.”1043 NARROWI%TBEAM AND “LOWESTSTERNPkT ANGLEI LONGESTWETTED LENWN I I

#

!043-0[ I~0.376 IN. FWD. OF STEP UPPERLIMIT [0

“ 6.75 IN. ABOVEKEEL>: S.— --- - ‘..

& ~

1043-03 C.G.=1.50IN.FWO.OFSTEP6.75IN.ABOVEKEEL lJ-

-10z

— 6

LOWER LIMIT- a

1043-02 : 4Y

. OURVESOF ZERO TRIMMING~MENT FOR P~lUJLAR C.&

2

0.20 0.15 _ , 0.10 0.05 o“dGA/cv

I 1 I IMODEL NO. 1044 WIDESTBEAMAND HIGHESTSTWWOST ANGLE

w RTESTwETTED LEM3TN .h \

1044-0 I0.375 IN. FWO. OF STEP

c.G@&75 IN. ABQvE =L\~..-. —-- -— —---— - UPPERLIMIT

_--— --—.—w %‘\ W

\\N.

&\ x .

--% ~-

LOWERLIMIT-~G .1.S0 IN. FWD. OF STEP—~—t

. 6,75 IN. ASOVEKEEL ~

- CURVESOF ZEROTRIMMINGMOMENT~ . PARTICULARC,G.

=&$=

0.20 0.’5@/cvalo 0.05

. . . .

- 16

- 14

- 12

- 10

- 0

- 6

- 4

- 2“

“o

Figureu.- Curvqsfordeterminingg longitudinalcenter-of–gravitylocation.

—..—-—- .- ——- .—— — —.——- -.— .—

50 NACATN 2503

DESIGNATION:3.71-0.95-20MOOELNQ !043-06 0.29bFMl OFSTEP

CG= Lt4 b~~ ~Cti=~;:3(WW TESTEDATSJ.TN0,3TW

tbxL BEAM5.25” =, DATE: 2-19-48

).091 I I I I I I IFREE-bTRIM RESISTANCEANDTRIM

).00 DISPLACEMENTRANGE

n TRIM107 I I I I4-

/“q = I.o’d i2-

/.’0.85 d

&lo-4

Ml-4 v /“ ‘ Yg+3-

— 4L03 d-

- ~102/

LolG;/G’:

2-

16 I

14 T.

.

.

Figure15.

.

_— -——

51

NAc ‘-’”

%+=2%?4AT10N:371‘U.93-zuGAO=1.123(NO~’wOFsTEP—

\oAJ=— I I ! I 1

.0.07 --

R~Slm GE.0.0 6-$

(s

-M 3’

4.02

. I

1

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I

,-

IL12 all

=s= –

ao5I

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_— —––-—————”—_. —- —------

—.. —.————-——. -.— ... ——-. . . .

52 mm m 2503

DESIGNATION:3.71-1.19-20MODELNQ J054-01

GG=~ : ~:=~pC&X~i~j4(WlWlJ T~UD ATS.I.T Nom3TAN

Moon Bw~ 5.25’ - ma DATE: 6- 24-4B

HULLLINES

----

ao9 - IFREE-TO-TRIMRESISTANCEANDTRIM

Doe DISPLACEMENTRANGE

no7

%0

).02P

).01

1234 $ f? 7 e ? 10 1,1 I? 13 Is l? Ip IT Ip Is

14

12

10

t

.—-— —. .-— —— ——

NACATN 2503 53

I

Figure18.

DESIGNATION:3.71-1.19-20MOOELNcL1043-05 ~G=023 b FwuOf Cao=1.123.(NOWW TESTEDATS.I.T N~3 TNKhbDELBEAM 5.25” 1.24bABWEKEEL kA=o.203 DATEI 2-5-48

ao9 I I I I I I IFREE-TO-TRIMRESISTANCEANDTRIM

ao8 ,DISPLACEMENTRANGE

ao7-

OQ6~ 12“Oa

ao5-u> .10~K

.ao4-(Y :$-8-

a03- &-z

0.02a4-

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2-

1 $? 3+ ? 6 r ? ? 10 1,1 12 13 14 I~ 16 1,7 (i3 19

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2-8-3

~ I–g-~ I I ---1-.

RESISTANCEANDSTABILITYCHARACTERISTICSPLANINGRANGE

s–4 gMq/V;b4= .s

–f!~5 K/c”

03s 030 (X?O 0.15 0.10 0.05 ,,

— —. -. -. . —______________ __ — ---—-.——. —..———. —.

,

54 NACATN 2SOS

DESIGNAmON:3.71-1.58-20MODELNa 1043-04 0.29 b FWD.OFSTEP

G@ 1.24b~“~ ~C,m=1.123(~lNIW TESTEDATS.I.T.No.3 TANI

WDEL BmI 5.25” k/L=0.203 DATE: 11-19-48

Q09. I I I I ! I IFREE-TO-lkIMRESISTANCEANDTRIM

maDISPLACEMENTRANGE

Q07. 14’

- S4RES16TANcE— — — — — n UM 12

\ 0ao9--~ ~ ‘- I

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QQI / “2-3 - %;/6’;

1 8 3 4 $ 9 r 9 v 10 1,11? 13 14 I51 P 17 1P 1?I-16

-14 y.

Figure19.

— -.. .— —

NACATN2503 55

.

DESIGNATION:3.71-1.58-20MODELNo. 1055-02 ~G=0.29b ~ OF Cbo=1.123(N~l~U TESTEDAT S.I.T.No.3 TANMODELBEAM!5.25” 1.24bABOVEKEEL k/L”o.173 ~TEx 12-2’7-48

2s ! .3- HULLLINESLOCATIONSOFTANGENUESOFFoREBOOySpRAYBLISTERENVELOPES

FREE-TO-TRIM,DISPLACEMENTRANGE?.4 -e-

m

>

~ s= ‘1,6-oa W< ,o-

1.2 !: -/ ‘

0.s J.2-

DASTATION9W31Nf3GWENAS

-3-cv*/c#~ DISTANCEFROM

I * 3 4 5 6789 Q II Ig 5 1+ STEP,IN UNITSOFBEAM

0.09 ! I I I I I IFREE-TO-IRIMRESISTANCEANDTRIM

008pISPL,ACEMENTRANGE

0.07

0.06-c 1:“8

OK)5=J— — RE51STANGE\

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RESISTANCEANDSTABIUm CFb3RAcTERiaCS 0.05 K/h “ ao4I

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-4Mq/@b4 =

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0.35 030 a25 -020 0,15 0.10 0.05

.

Figm?e20.

— .——--.- —-.. ~.— —.——. —.. — -...—.—— .— .—— .—.-. — -

56 NACATN 2503

DESIGNATION’3.25-0.83-20MODELNQ 1024-0S ~#: : ~m~-~ C&s().733 (NWl~) TESTEDAT S.1.7. No,3 TANK

MODELB* 6.00” “ k/L=ow3 OATE: 4-27-48

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DESIGNATION’3.25-1.04-20MODELNQ 1056-01 an. O.25bFWUOF C6.=0.753 (WIW TESTEDAT S.1.7. No.3 TwK

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Figure23.

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NACATN 2303 59

DESIGNATION:3.25-1.04-20VIODELNQ 1024-01 0.25bFWLiOFSTEP

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60 NACATN 2503

DESIGNAmON:3.25-1.04-20MODELNet 1057-01 ~.,0.QSb ~ OF (2,.=0.733(~- TESTEOATS.1~ No.3 TANKMODELBEAM6.00” 1.08bAWiEKEEL k/L=o.l 73 i)ATE: I1-19-48

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NACATN 2>03 61

DESIGNATION:3.25-1.38-20MoDELNQi056-02 (@~ : ~K~ Cb.=0.753 (WINAL) T-AT S.I.T No.3 TANHMODELB- 6.00” “ k/L=o.244 DATEI 8-23-49

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DESIGNATION:3.25- L38-20AODELNC 1024-02 a25 bFWD.OFSTEP“

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DESIGNATION:3.25-1.38-20MODELNQ 1057-02 0,25bFWllOFSTEP

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DESIGNATION:2.89-0.74-20

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66 NACATN 2503

DESIGNATION:2.89-0.93-20MODUNa 1058-01 ~G=Q!?2b~ OF C~.=0.529 (~~ TESTEDAT Sol.t Na3 TANIMOML BEAMI6.75” Q96b ABOVEKEEL kAQ.M4 DATE: 1-7-49

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68 NACATN 2503

DESIGNATION:2.89 1.23’20MODELNQ 1058-02 ~@u!2 bFWD.OF Ca.‘~~ (~1~) TESTEDATS.1.1No.3 T~NIt#XEL8EbMI6.75” 0.66 bABUvEKEEL kAa244 mTE: 10-31-49

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DESIGNATION:2.89-1.23-20

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70 NACATN 2503

DESIGNATION:2.89-1.23-20MODELN121059-02 ~&.22 b~ OF C&KL529 (NOMIW T~EO ATS.I.T No.3 TANKMODELBw 6.75” Q96bABOVEKEEL kA”oo173 DATE: 12-21-48

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g-

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Figure36.-Staticpropertiesat CM= O withconstantbeamaridvaryfngstewpostangleandafterbodylength..

.— —-- -- ——.--— .__-— –—.. —..—— —-——— . .-. .—— . . —-. ——. —-— —-.--—

72 NACATN 2503

I I I

~6 +

SHORT AFTERBOW. MOOELNO. 1054-01 6

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Figure37.-StaticpropertiesatCM= O withconstantsternpostangle

andvaryingbeamandafterbodylength.

.—. .—— —. —.. ——— —— .-

10,

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NACATN 2303 73

L02

‘m

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ISHORT AFTERBODY

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z

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Figure38.- Numberofskipsencounteredon landingofshort-andmedium-afterbodyhulls.Grossweight,3000poix@;wingloading,11poundspersquatefoot. .~.

.———____ ..__ ._ –——-— . —.— ._—.—

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SHORT AFTERBODY( MODELNO. 1056-02)

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Figure39.- kmber ofskipsencounteredonlandingofshort-andmedium-after%odyhulls.Grossweight,3000pmnds;wingloading,14.5poundspersquarefoot.

.,

.

NACATN 2303 75

,

DESIGNATION:3.25-1.04-20

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Figure~.

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76 NACATN 2503

DESIGNATION:3.25-1.04-20MODELNQ 1220-01 CG=0.25bFM’UOF C,.=0,753 (WWALI TESTEDATS.I.T.No.3 TMHMODELBEAM6.00” 1.08bASOVEKEEL kA90203 DATE: 6-30-49

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Figure42.

DESIGNATION:3.25-1.04-20

0.09 ! I I I I I IFREE-TO-lRIMRESISTANCEANDTRIM

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Figure43.

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4

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STEP DEPTH 8.3’9’0 BEAM( MODELNO. 1221-01 )

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1

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FigureM.- Effectof stepdepthonnumberofskipsencounteredonlanding.Warped-afterbody-hulls;grossweight,3000pounds;wingloading,14.~poundspersquarefoot.

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

Ftgure4s.-EnvBIopeof .@.erbody-roachproffle. Constantiltico-on of free-t~trimtestsat zerotrimmhg nmmentjforBhort-sftarbo@-mdel no. 10~I!IJJland medium—al%rbodyIilodel.no. 1o43.

t

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s’

FigureLT.-Envelop of afterbody-roachprofile. Conetaut-loadoompwison of free-to-trimtestsat zserotxdmningmomentforshort-afterbodymodeluo. 10j8-01andmedi~afterbo@-modelno. 104.4.

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2.4

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Figure 48.- VariationofresistanceandtrimwithspeedformodelsKLtia shortafterbodyandsternpostangleof 60. Constant-1oadcomparison;initialload,5.86pounds;take-offspeed,35.6feetpersecond.

NACATN 250384

2.4

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Figure49.=Variationofresistanceandtrimwithspeedformodelswitha shortafterbodyandstempostangleof8°. Constant-loadcomparison;initialload,S.86pounds;take-offspeed,35.6feetpersecond.

. . — —..—— . —.

2.4

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Figure.50.-Variationofresistanceandtrimwithspeedformodelsvi.tha mediumafterbodyandsternpostangleof60. ConStan&loadcomparison;initialload,S.86pounds;take-offspeed,3S.6feetpersecond.

.—— —— . ———

86 NACATN2503

2.4

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FigureS1.-Variationofresistanceandtrimwithspeedformodelwitha mediumafterbodyandsternpostangleof80. Constant-loadcomparison;initialload,5.86pounds;take-offspeed,3S.6feetpersecond.

NACATN2303 87

2.4

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52.- Variationofresistanceandtrimwithspeedformodels-a mediumafterbodyandsternpostangleof10°.comparison;initial.load,~.86pounds;take-offsecond.

I

withEonstanbloadspeed,3S.6feetper

---- —.— .—-— .. —.– — ——

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6

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Figures3.- Variationofresistanceandtrhnwithspeedformodelswitha longafterbodyandsternpostangleof6°. Constant-loadcomparison;initialload,J.86pounds;take-offspeed,3S.6feetpersecond.

,, ‘.

.

.—

12 NACATN2503 89

2.4

2.0

1.6

1.2

0.8

0.4

0

6

\ 5

. —DISPLACEMENT dJ

-2 - 4

w“1=z

-zw

— fi. 3e

\\u) o

G WIDE BEAM- 3$ — & 2

MIDDLE BEW aNARROWBEAM-

/ I

o 20 40° “

16

14

12

10

8

6

4

2

0

SPEED,FT./ SEC.

—

I I I I I I I P=@=0 40

SPEED,20~./SEC.

Figure~4.-Variationofresistanceandtrtiwithspeedformodelswitha longafterbodyandsternpostangleof10°0 ConstantiloadComparison;initialload,S.86pounds;take-offspeed,3S.6feetpersecond.

—.—.——— ~— — -—___ .. . ——

90 NACATN 2503

SHORTAFTERBODY10 I I I

I9.0 INCHES FWO. I

..-— AT STEP I

..2

II I

! ““l ~I BEAM, IN. II BEAM,IN. I5 6 75 6 7

0

MEDIUMAFTERBODY10 ~ I I I I

I I AT STEP I I

5 60 ?

1 I BEAM.IN. I I

‘7 6- 7

10LONG AFTERBODY

I I I I9.0 INCHES FWD.

OF STEPAT STEP

82.

6:

9g. \

\ \4 6°

%\

~ - I& U= 6:l&

u)2

BEAM, IN. BEAM, IN.s 6- 75 6-

0 T

I I I9,0 IMJIES AFT.

OF STEP

\

g.\ &lc

BEAM, [N.

?6

I I I9.0 INCHES AFT.

OF STEP

g.

\ 10°

1 e“-

6°

BEAM,IN.5 9

I I 1

9.0INCHES AFTOF 6TEP

—u.

%10°.

6°

BEAM,IN.s 6 7

Figure~~.-Variationofmodelsprayheightwithbeamatthreelongi-tudinallocationsalonghull.forfree-to-trimtestsat zerotrimmingmoment.Constantiloadcomparison;initialload,S.86pounds;take-offspeed,35.63feetpersecond.

—.— —. . .

NACATN2’j03 91,

1000 SHORT AFTERBODY

MODEL NQ DESIGNATION STERNPOSTANGLE800 -m

-1

600 - lli-2

400 -g?5

200 -~

[0 “ 20 30 40 50 60 70 80

1000 MEDIUM AFTERBODY

DESIGNATK)N STERNPOSTANGLE800 -“

5

600 - ll.i- / <

2400 -g

200 -a/4 SPEED, M.P.H.

/’00 10 20 30 40 50 60 70 80

I000 LONG AFTERBODYI I I I I I I I

MODELNO. DESIGNATION 6TERNPOSTANGLE800 -j 1065-02 3.71-1.58-20 6°

g. 100= 1055-03 3.71-0.95--20600 - g“ 1. I I

h-~-%-. . I

\*--~.. &

400 -gu s k% ‘\ \.

E/ . - —. . —. \

\ \200 -a \\.

SPEED, WI?H.\1

[0 20 30 40 50 60 70 80

Figure56.- Variationofresistancewith.speedfornarrow-beamhulls.Comparisonwithconstantforebodyplan-formarea;grossweight,3000pounds;take-offspeed,68.7milesperhour.

v

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

92 , NACATN 2503

Q

1000 SHORT AFTER80DYI 1 I I I I I I

MODEL NO DESIGNATION STERNPOSTANGLE

800 –“ 1056-Oe 3.25-1.38-20 6°5 (7s8% * 1056-01 3.25-1.04-20

600 – w-0°

\

~ 0“/ ~c6 02- -’?% J

400 –~ ,/ .5 — ~

200 - E /I

/ SPEED> M.1?H..*M00 10 20 30 40 50 60 70 80

[000 MEDIUMAFTERBODYI I I I I I I I

MODELNO. DESIGNATION STERNPOSTANGLE800 –~ 1 3.25-1.38-20

d6°a s 100%

3.25-1.04-20 8°600 – g“ 3.25 0.83-20 10°

z

400 –~ ---- .--

4\

200 –\\.

I ISPEED, M.P.H.

oo~ I

10 20 30 40 50 60 70 80

LONG AITERBODY -1000 I [ I I I

MODELNO. DESIGNATION STERNPOSTAN(3LE800 -j 1057-02 3.25-1.38-20 6°

1057-01 3.26 1.04-20 8°600 – g t- 1 1057-03 3.25-0.83-20 10°

z

400 -g / , .z / o s 6°/ -- - -_ \—- .

F‘ -q \

200 –$ i\I I

SPEED, Ml? H./’

00I

10 20 30, 40 50”60 70 80

Figure57.-Variationofresistancewithspeedformiddle-beamhulls.Comparisonwithconstantforebodyplan-formarea;grossweight,3000pounds;take-offspeed,68.7milesperhour.

.

.

NACATN 2503 93

.

1000 SHORTAFTERBODYI I I I I I I I

MODELNO. DESIGNATION STERNPOg ANGLE800 -m -1058-01 2.89 -CL93-20

J Oae<0°

600 - g“ / ~ \ . tz

400 -E

200 .$\

SPEED,M.P.H.I

‘o 10 20 30 40 50 60 70 80

1000 MEDIUM AFTERBOI)YI I I I I I I I

MODELNO. DESIGNATK)N STERNPOSTANGLE800 -~

-1 g s 100 _ -1044-05 2.89-1.23-20 6°\ \ 1044-03 2.89-0.74-20

600 - g-10°

/ /’ ,\z ?-’.

4~ -$ — - — — — . _--- .—-. —.%’\

~ +

SPEED, M.P.H.I t

30 40 50 60 70 80

LONG AFTERBODY v1000, I I I I I I I I I I

I MODELNO. DESIGNATION STERNPOSTANGLE800 cj I -1059-022.89-1.23-20 “ 6°

g s 100? IOS9-03 2.69-0.74-20 . 10°

/~ 6-’ .//’

\.\. \

A+\- +- -%

600 -g- –z

400 -g- –z Q . “6”A /- >--- - k

200 -~ /%

/ \/ ‘ SPEED, M.P.H. \\

00~ 1 [10 20 30 40 50 60 70 80

Figure58.-VariationofresistancewithspeedComparisonwithconstantforebodyplan-form3000pounds;take-offspeed,68.7milesper

forwide-beamhulls.area;grossweight,hour.

. . —. —.-._________ _. _._. ____ —— .-

94 NACATN 2503

.

.SHORT AFTERBODY

6 I I I I6.0 FEET FWD.

OF STEPAT STEP

4 t

Ii

3:- ~ Qs–8°

B2> ~ a.-

a 0°Kco

I

BEAM.FT. BEAM,FT.i5 I 4.0 I 453.5

0 I 4b I 4.5

MEDIUM A.FTERBODY.—

u.

3.s 4.0

I 50 I%ET AFT.OF STEP I

!

BEAM,FT.3.5 4.0 4.s

-(7.100.

e“-

— — - 6°—

] BEAM.FT. I

LONG AFTERBODY6 I I I 1 I I I

6.0 FEET FwD. AT STEP 6.0 FEET AFT.OF STEP OF STEP =:

4 I lo—F .la.

g. g.

3:- 6°– 4 6:10°-g I0°w 6°s

2sK% =S=I

BEAM,FT. BEAM, FL BEAM, FT.3# 4q 4.5 3.s

o4.0 4P 55 4,0 4

5

5

Figure~9.- Variationoflocationsalonghull.areaforfree-to-trim3000pounds;take-off

sprayheightwithbeamatthreelongitudinalCo~arisonwithconstantforebody~lan-formtestsat zero trimming moment;grossweight,speed,68.7milesperhour.

,

NACATN 2P03

SHORT60 I 1 1

I TAKE-oFFSPEEOI 60M.RH.

60\

H40 mw“

\z

30i=

ko

$20i!s

10. BEAM.FT.

3.5 4.00

g,— eO-

6°

1=

4.3 :

50MEDIUM

f I I I

I TAKE-OFF SPEED60 M.RH. ~ = I

40 t6

, I0°w ●UJ.

30 g1= 8°

k6°

200IL~

10BEAM,FT.

RBODY .

==7t

6°

BEAM,FT.4.0 4.3

ERSODYI 1 I

TAKE- OFF SPEED68.7 M.P.H. ~,

R’

10°

0:0

+&--t-i3;5 4.0 4.6 is

o4.0 I 4.6

‘0r-i=$_rr%KF-l

3:5 4.0 4.3 3.5 I 4.0 I 4.50

95

,

●

6°-

BEAM,FT.3.9 4.0 4.6

I ITAKE-OFF SPEEO

77.4 M.P.H.

o%-

BEAM,FT.3.5 4.0 I 4/3

t 1 ITAKE-&F SPEED

77.4 M.I?H.

gay “ I0°60

‘=5=I

BEAM,FL3.5 4.0 4.5

Figure60.- Variationoftake~ffthe withbeamforthreetake-offv speeds.Comparisonwithconstantforebodyplan-formarea;grossweight,3000pounds.

. ...— — —— .—. —-— —. —. ..—

96 NACATN 2503

‘.

..

Figure61.-Variationofresistancecoefficientwithtrimangleat90percentoftake-offspeedof68.7milesperhour.Long-afterbodymodelno.10s7;~ = 7.99;CA = 0.I-43.

#

[

I

1

I

I

I

1,

II

I

I

185 H.P. ENGINE

I70

THRUST ttORSEPOWERREQUlm

160

E )—

t

150 !

k— = 135 M.l?H.—

140

I 30

AIR SPEI?D, V , M.P.H.

130 140 159

215 H.P. ENGINE

190 t

THRUST HORSEPOWERREQUIRED

1s0

170 gTHRUST

H&3~m~R

–i

1

130t (

1s0

AIR SPEED, V, hl,P.H.

140 I 50 I 60 lea 160 170

Figure62.- Curvesof poweravadlableand powerre@ed.u

98 NACATN 2’jOj

.“

1200

1000

800

600

400

200

I TAdE-OF# SPEtD=66.0 M.t?H. 12<TRIM TAKE-OFFTIME =27.9 SEC.

. 108

9, \ o e

u-)/ ‘-= -

I RESiSTANI

1“ -1

uI I

1-

00 10 20 30 50 60 70 80”

SPEED~M.RH,

I 200

,1000

800

600

400

200

00

1200

1000

8(X)

600

400

200

0

I I I I I I [2—TRIM TAKE-OFFSPEED~6S.7 M&H.

TAKE-OFFTIME = 27.7 SEG. 10

— _\ / F THRUST E

-IIJ / 0 8

9-w- 12

i g 6

ea

— — —= 4

/— —- . 2

n10 20 30 50

SPEEO:OM.P.H.60 70 80-

I 1 I I 1 r 12—TRIM TAKE-OFFSPEED877.4 M.P.H.

TAKE-OFFTIME =29.5 SEC.. 10

E ~-1 w-U“ / — - -1

8‘= g 6

.@ \ ~ a/ 1. \ _ ~ 4

RESISCQNCE,R- ‘“ --- __ b2

AIR DRAG,D-\

o0 10 20 30 50

SPEED:OM.RH.60 70 80-

Figure63.- Curves fordeterminingtake-offtimesof short-afterbo~hull.Modelno.10~6-02;grossweight,3000pounds.

“

-—

NACATN 2503 . 99

1200

1000

800

600

400

200

0

I200

I000

800

600

400

200

0

limo

1000

800

600

400

200

0

I 1 1 1 12—TRw TAKE-OFF 9F&0 ==0 M.P.H.

XME-OFF TIME ~3U SEC.10

● -

\ 81 0 8

J“ 3------~ ,. : 6\ -R-“P

{ . . ~ 4RE91ST~ R- >

\E

/ 2

\(3

0 10 20 30 40 60 60 70 6D-

I I 1 1 1 1 , IQTAKE-OFF SPEED= 6S.7 M.RH.—

\ TAKE-OFFTIM~I I I I 10

—. _ THmJsT/ “> - 8“

. . k 3~ 6

-R*D“* \ —

{ . SE 4---

RESISTANOE,R+ ~“ E---/

+---2

\n

o 10 30 ’40 50SPEED M.I?H.

60 70

TAkE-OF# SPEkD87~.4 M.’I?H. “-

9“.

‘!$.R

~

10 20 30 ‘. ““40 50 60 70 60-SPEED M,l?H.

Figure64.- @nnres fordetemdni.ng-take-offtimesofmedium-afterbodyhull.Modelno.102@l; grossweight,3000pounds.

. . ..-— —-- -———.-—— ——

100

I200

1000

800

600

400

200

0

— I t I

—TRIM TAKE-OFF SPEEOx60.0 M.RH.TAfE-WF TIME * S0.1 SEC.

f

t

*

> Id 1.

g

\

RESISTANCE,R~ ~ E

AIR DRAG,O+ - .~ ~ ‘ --- -%I I

12

10

8

6

4

i?

o0 10 20 30 50 60

SPEED*M.PH.70 80-

4

I200 — I I I I 8 I 12TAKE-OFF SPEEOx60.7 M.P.H.

1000lAuE-OFF TIMc = 30.6 SEC.

1 10H

800 -~ n 8d Ill

600 “-

Ii!

-1g 6

\ a400 _ /~ %

L ~ 4RESISTA?+C&R“ “ ‘-N \ E

200---

i I -- .~ ~ -

“ 2AIR 0RA6, 0> -.

“\1 I “o

o 10 20 30 50SPEEDWMJ?H.

60 70 80-

1200

I000

800

600

400

200

0

T— I 1 I 12TAKE-OFF SPEEO977.4 M.P.H.TAKE-OFF TIME -31.4 SEU.

f 1

/ -THRUST g ‘0

~ — — \ F 83 w

g/ -. \ $ 6

_aI& / / ‘% s 4

~ . _ . _ E

2

\n

10 20 30 mSPEED40M.EH.

60 70 80-.

Figure65.-Curvesfordeterdningtake-offtimesoflong-afterbodyhull. Modelno.10~743;grossweight,3000pounds.

NACATN 2303 101.

[2

10

8

6

4

2

n

I—. -UPPER I!IMIT-—

$j. .

LOWERLIMIT- :, ‘-’ CM=. -0.2

u“ \ -o. I4 \ \

2\ \

\ Ia \ \ 0.0

-EE 31- TAKE-OFF SPEEDu60.0 MJ?H. +%

t +0. 1

I I+0.2

SPEED, MJ?H. I-o 10 20 30 40 50 60 70 . 80

12 I I IUPPER LIMITA. I I

. I -o.2~

I I -+.. I I I I=. I

4 -~E TAKE-OFF SPEED=68.7 M.P.H.

2

r)“o 10 20 30 40 50 60 70 80

.

12

10

8

6

4

2

00

I 1

-- UPPERLIMIT v---\. 4

LOWERLIMIT- \ --- -.8 \ GM=-a , \\ \

-0.2i, --- __y“ \ ‘. -0.1

-g ‘\.\ .\ ‘\

a \.sz1- TAKE-OFF SPEED= 77.4 M.RH.

Figure

10 20

66.-Longitudinalhull. Modelno.

30 40 50 60 70 60

stabili’@characteristicsofshort-afterbody10~6+2;grossweight,3000pounds.

102 NACA‘I!N2503

12 I I --- I--LOWER LIMIT- \ -. __ -- -UPPERLIMiT

--- --10 . \ I

-0.2 = CM8 ‘1 -o. I

8 ‘n-\%\\

Lli” \ =-\ 8.5 .\

6 .: 0.0

a

4 -~a1- TAUE-OFF SPEED=60.0 M.i?H.

2

00 10 20 30 40 50 60 70 80

12 I I

10 -.--

\ -.8 -.

8 -n--.

\36 -ga \

4 -~E lZME-OFF SPEED=68 .7 M.P.H.

2

f)’-o 10 20 30 40 50 60 70 80

12.

I I --:-- -==- :--_: - ‘- :.

10 . . -- --- -L .

g ‘\-

8 ----

.\lJ- \ --

-- ~6 -g J= 0.0

\a \’

4 -zE1- TAKJ5-OFF“SPEED=7Z4 M.P.H.

2

00 10 20 30 40 50 60 70 80

Figure67.-Longitudinalstabilitycharacteristicsofmedimafterbodyhull.Modelno.10U41; grossweight,3000pounds.

‘.

—. . ——— —.-.- -..

NACATN2~03 103

14

12

10

8

6

4

2

CM=--——---..=-- — . .LOWER LIMIT= “--- ‘--- -.%

r -- ~o.26

-0. Iw

L. -. 3 - uPPER UMIT—n \ ‘.-

---lAi- ‘- 0.0-1 \w \,zaz \E \1-

TAKE-OFF SPEEO=60.O ?AP.H.

o-o 10 20 30 40 50 60 70 80

14 IUPPER LIMIT- CJ =

12 --- --- -.~-~- I

LOWER LIMIT= ‘-- ‘-- --- ~------- =_- -0.2

-0.110 -g t I

n \ +- -\ =--\\\ --- Q

8 - k.---- . 0.0\

0 \ \ 9.6°6 -5 \. R\.

E.\\

\

4 -gTAKE-OFF SPEEO=68.7 M.P.H.

2

00 10 20 30 40 50 60 70 80

14

12

[0

8

6

4

2

n

f IUPPER .LIMIT- \ & sd—--- ---- I:--

LOWERLIMITs ‘- ‘-- “-+- .-—.___ __- -_ __ -0.2d1 -- -0.1

.$ -..,n --- -- _ --- -__

“kj-\ N

%0.0

\0 ‘\ 9.4°

-5z \\. - ~E

‘l- .%

..

TAKE-oFF SPSEOs 77.4 M.RH._- ~+o.l–

“o

Figure

10 20 30 40 50 60 70 80

68.-Longitudinalstabilitycharacteristicsoflong-afterbodyhull. Modelno.10s7-03;grossweight,3000Po~dS.

. . ... .-. .— —.— .-. ..———..—. .. —.. — _. —___ —_________

EFFEOT W INOIW3SED FOR-Y WIRPIND ANDCONGAVE FO~ SEOTIONS ON MAIN - SWAY HEW

mm-m -TRIMTEs-rsAT 7XR0 TR.IAH3 mMENT

CONSTANTLOAO OF 6.45LB.

,—,

I I I 111111116 It s’ EoO

L0NG4~DlNAL hCKllON ,; , IN,s Ie 16

16 1!2.6 oLONGkAL LOOATION,: , IN.

e Ii? 16 20 “

Figure69.- Effectof variousfactorson mdn-spray height.

14 105

-1.4 -- -—— -

-1.2- .~. I7

-1.0--Uj HMOD~ NO. 1024-01 w

-o.8- “g“z

-().6- .$ ,MODELNO. 102+05

-ck4--E I tWE NT H~LL wW,T SPpY STRIPSjY

-0.2 c I SPEED FT./ SEC.

?’ 10 [5

-[2

L _ _ _ _ ----—”-.—-- -----

-10 ) /MODELNO.1024-01

( PAqENT) /1

-a .

_ J!!( PARENTHUU

u--6- .9

<— ~

s-4

,.

/ ‘-2

-. -I SPEED FT /SEC.9 10 ..1 . . . [p .

,,Figure70.-Effect”of spray‘st~pqonr&is&nce qndtr& h +kplacement

speedr“ange.Free-to-trihtestsat zero trimming:qomentofmodelno.1024tith a CO~t~t 10ad Of 5’.45POW*.

.

———.—— -. —.. —— ---- .——— —.-..A— . ..—

106 NACATN 2s03

t d- ‘ NooEL NO. 1!222-01‘++( INCREASEOFCRESOOYW3RPINO). , .

-1.0-“9 WIkL NU. IUW?-U)

(PARENT)

-0.8--u” /2

?

-0.6-‘=

nMOOELNO. 122041

-0.4- K(CONCAVE FOREBOOYWITNCUTSPRAYSTRIPS)

r //

-o.2- \/0” I SPEED lW/ SEC.

? Ip 16

-12

-10

(CONGAVEFORESODY

i-6- ‘: /

‘/ .“’

— z/ < H

~ ‘/

E /–4

h100ELNO. 1222-01( INCREASEOFOFfEBOOYWARPING)

/ /.,/’% --- --- ---

-

I SPEED 1% I SEC. ‘5 Ip 15

Figure71.-sectiomtestsat

Effectofincreasedforebodywarpingandconcaveforebodyonresistanceandtrimin displacemmtrange.Free-to-trimzerotrimmingmomentwitha constantloadofs.4Spounds.

— .——. ————— —— .—.-.

I

{

I

I

I

i

12

GM a 0.0 : \

10 I‘\

MODEL NO, 10~4-01It \

8MODEL NO. 1$2!2!2-01

G - \\I.Ll

MODEL NO. 10$?4-01

n\

/ ( PARENT)\

w“ I

6 $

\

LOWER LIMITS $ fMODEL NO. IEZ12-01

== {INCREASED

E FOREEODY WARPUW )

4 % 1

2

2bEED ~. 1 SEG. T

o0 10 20 30 40

Figure72.- Effectof increasedforebmiywarpingon lowsrtnlm IimLtofstability.Initialload,5’.86pounds.

I

108 NACATN 2503

,

-1.6\

1.4 \ / “\

[.2\

\ \m“ \ MODEL NO. 1024-01d \

.1.o- *( PARENT’)\

\ K /~w \ //”

---a8

----- .- 26 FT. / SEG._- “j _MOOEL NO.12$?1-01 A = 4.0 LB.

(WARPEDAFTERBODY)~6- GJ

a0.4

0.2 TRIti ANGLE, DEG2 4 t; 10 I2 14 I6

I.2 2{+\ MODEL NO.1024-01-

\rL8– g-

30 FT. / SEC.\

z 13 = 2.0 LB. —\

0.6-.fj \65 =-. — - ‘MOD EL NO. 1221-01

0.4--*

0.2 TRIM ANGLE, DEG.2

12

JMODELNO. 102401 —

0.8-. g35 FT / SEC._

\ /z. \ / ~ = ~e~ LB.g > /

o.6- ~?5 / ‘MODEL NO. IX21-01

o.4--1#

-0.2-- 1 I I TRIM APK3LE, DEG I I

2 4 6 8 10 1? 14 16

Figure73.- Effectofatterbodydeadvrisewarpingonhigh-speedresistance-characteristics.Fixed-t& test;modelno.10z+l~ st&npostangle,8.OO;modelno.1221-01,sternpostangle,7.sO. .

“

.——. — ———- —

NACATN 2503 109

.

4

o

12

10

4

2

ST’EP DEPTH ‘4.2 % BfiMSTERNPOSTANGLE So

( MODELNO. 1024-04) -

WARPINGAFTERBODY( MODEL NO. 1221-01 )

o 2 4 6 8 10 12 14CONTACTTRIM, DEG.

I I I ILANDINGTRIM‘AND‘ SPEED

I

\ FORWINGLOADING14.5 LB. / SQ FT.

\ ANDtGROSSLOAD OF 3000 LB.

I I I I I I I I I I I I I 160 70 80

LANDINGSPEED,M.RH..

Figure74.- Effectofafterbodydead-risewarpingonnmber ofskips,encounteredon landing.Grossweight,3000pounds;wingloading,14.5poundEpersquarefoot. ..

—.—~. .-—._ .._.

110 NACATN 2503

‘.

.

UNDERWATERPHOTOGRAPHQFFOR~ODYAND~ERBODYWETTED~EA

Figure75.-Forcesona fl@ng-boatha modelintwo-steppi-g.Modelno.102~4~(parentwithforebodyspr~ stfipsremoved).Aotualtestconditions:load,5.33po~~; wee% 12feetpersecond;andtrim,1-1.9. ‘

NACATN 2503llL” -

~ DIREO’flONOFMOTION.—---

( lr~

/

/ LOO*

LNR

.4

M+;:

11.5° / y“

/ /

~R%OY ~EE1

I1.5 II&

k-

O.sf$il

-1

1.@ 1,3.74.

FORCEDIAGRAMFORFOREBODY

Forebody:

L -&.7hlb.(reference18)

N - L#&9=4.8Llb.(approx.)

Df= 0.16 lb.(refer@we18)

~DIRECTION OF MOTION

AFTERBODYLENQTH~20.S5n )

M- .IllLI

5.8°

N. ‘“74 +c~;Mus~nOr =4.87 (actual)●

[1 . .STERNFOST

I L, VERTIOALTOI STILL WATER ‘

FORCEDIAGRAMFORAFTERBODY

Afterbxiy:

L = 0.56 lb.(reference18)

Ll%L

0.56~.— = 0$6 lb.(approx.)C085.8°

Becaueean~esconcernedareamml,momentarm=20.25 + l.!io - k.8=16.95in.

Homntduetoforqbodyforms● 4.87x2.2h- 0.16x5.95=9q96’in.lb.Momentduetoafterbodyforces--0.S6X16.95=-9.49in.lb.

Liftopforebody=4.74U.Liftonafterbody- .% lb.

Total=‘SJOlb.=ss

modelh two-stepFigure76.- Forcesandmomentsona flying-boathullplq. Modelno.10@3~ (parentiwithforebodyremoved).Actualtestconditions:Load,5.33pounds;speed,12persecond;trim,ll.~”.

sprays@ips

. .

.

feet- \

_———___.. ... .- .—. — —. —.— —.-——— ._.—

t“

~-. I 1111./’ ‘\

1000 U?(3SS WE16HT XXX) LB,/

t{

‘rAKE-cfF SFEED 68.7 MPtL ‘0

II I I I 11’f

1’-800 1

I \ 8

( \ /

/1 TRIM

\ .1057 -04 a“I u—

41290-01

.600

-.1

. ./! ‘ ;6

/:-

‘\\\

..---

EREsmlrWIE

-400 4-

\‘\

\ ,“

‘h

i

I

4 ~ -3

.-.

-zoo-+.

%

‘ ‘v”/

f

/

SFEED, MJ?H.10 eo 30 40 60 60 ?p

Figme 86.-Comparisonof trim and resistanceohai?acteristicsofNACA LOBEdesign(modelno. lp$IO+l)and E.T.T.design(IIDdelno. 1057-04).

E

I

.

15 NACATN 2503 113’

16

14

12

10

8

6

4

2

00

wo

w-dsazE1-az3s

Haza%

CALCULATEDHUMPTRIMANGLE, DEG.=2

()‘0.81- l.2~+ ~ Ca ,

a -

2 4 6 8 10 12 ‘ 14 16

Figure770-Comparisonofmeasuredandcalculatedhuq trimangle.

---——- --——— --—– -——-— —.. —- . . . _ _____ _

Ilk NACATN2503

.

5

4

3

2

I

o//

-.

$ CALCULATEDSPEEDCOEFFICIENTATHUMPTRIMz

c“ = ()1.14+0.60 ~ -0.023 (fl-7.5J2t

0’1

Figure78.-Comparisonof

2 3 4 5

measuredandcalculatedspeedcoefficientathuq trtiangle.

.

— —————-— ——. —.. — —

NACATN2503 115

,.

2.2I I I I I I I I IMODEL FRICTIONALAND DYNAMICRESISTANCE‘

2.0

1.6

1.2

0.8

0.4

n

,.“,”

60% GtiAWAY.,

MODEL FRIC~lONALRESISTANCE

‘O 4 8 12 16 20 24 28 32 36 40MODEL SPEED, FT./SEC.

cJRREc!ED iND lJNcOiRECT~D FJLL-&CALi RES’IsTAN~E.800

m.-1

.w2

-600 ~m

~rm 60% GETAWAY

\

\

\ UNCORRECTED\

-200 ‘~A -“ “ \“ ~\ “

\., CORRECIED~ N

v “ ‘i’

10 20 30FULL-SCALE

Figure79.-Modeland,

40 .“- 50 ‘. 60SPEED, M.I?H”.

full-scale resistance.

..——.... --— .—.—. ..._ —_—_ ___ ._ ——— ——

E.T.T. MOOEL1057-04

NACA MODEL 40-BE

II

10s7 -04 0 ,,MyQ ~ 7.50 ,W l~m I9.50

11111116,50

II

11.e3-19—

24W$29.00

I

1290-01

~ 6.0” -+

34.00I

39ioo

I

4e.50

I _L———————————

—._III

I I1220-01 ~Q am

o 1.2411:63

S.w?

M.guM W.- Comparison

ad E.T,T.deS&II

es.al19.aa 3e:92

3t02

of hull lineeof N40/L(modelno. IJX7-OL).

IJACATN 2503 117

.

I DESIGNATION:3.23-0.43-20 I

/ .- 1 \, L /

-a8- /~ — . 1

‘ HEIUHTMow! KEEL . m !.InE T/

-0.4,~c. , SA710NSWING GWENM

Gva/CJF3- wrAJwE FRw

I z 3 4567891~ Il. h? B 1$ STEP,IN UNITSOF BEAM

0.09. I I I I I ! IFREE-TO:lkIM ‘RESISTANCEANDTRIM

0.08. — — — — — — — — — — — — . DISPLACEMENTRANGE—16-

0.07, — — — — — — — — — — — — — — — — — — –14-

oJ36-.~ CA= ~lM“a m ~12-

Q

— glo- -/ <= -m

< ~5 - 2!

.&”eR

/ - z 8-RESISTAN0s F

,Q03 CA.a 6–L%

.0.02+9 ‘

(2571 ‘ 4-

/.0.01

ov@’~? Y 9 $ @ [ 9 9 Ip 1,1 Ig13141 pl $ 1,7 Ip Ip

-14

6 .kv 0s1 0.08 m7 aos ~-12 .

i

Q&UPPE LMT

-1o- 1$

--/

–8-S I/

EQ \

–6- \REsm4N OE ANoSTABILITYcHARAoTERlsl > ,

-4 PLANINGRANGEMq/V~b4=0.127 0.09 Qoa c107 \\\

\.

K/%oAs 0.$% OkO 0.15 ato

Figure81.

—— ——.=—._

,

118 NACATN 2503

3000

2000

1000

,,

—

\

m_-1

1= \-E

zw

2-(n5

\

\

I #SPEED, M.FIH. T \

.

0 10 20 30 40 50 60 70

Figure82.- Loadfall-offcurveforcomparisonofIWA l@E design(modelno.1290+1)andE.T.T.design(modelno.10s7-04).

\.

——— .

1

I

,1

II

““U4-J

-10

C (TRIM TRACK)

LOWER LIMIT-e

.-8

\ UPFER LIMIT\I \

IoI I p“%+?%;:)‘,,1 I ‘~\ I I I ., ‘w-

111e I 1

=&=

SPEED, M.I?H,o 10 eo 30 40 50 60 70

Figure 83.- Longitudinalstabili~ characteristio,gof NACA LOBE design(E.T.T.mwlelno. 1290-01).

\

1

i

II

TRIM TRACK FOR i087 ’04 -’ .,UPFER LIMITS

.10I

TRIM TRAOK FOR 1!290 -01

-e

—: -

-e- ;

3

–t

-4

-2

0 10 20 ap

Figure84.- C_on of longituctlnalstabilitycharacteristicsofU @BE design(mdel no. 1290-01)andE.T.’l!.design(modelno. 1057-04).

I

I

~6

i z>—

ii!12osm.6?. -N

g0’

0 [0 20 30 40 50 60 70 80 “90 100PERCENT OF ~EBOOY LENGTH

me 8.5.- CWarieOn of forehdy-bottm hej.ghtsof ~~ hO~ ales@(modelno. 1290-01) and E.T.T.design(modelno. 1057-Oh) atlh beamtidth.

.

.1

EN

“

d

+..~

12 10 8 6 4 2 0 2 4 6 8 10 If? 14 16

K)NGMQiNAL LOCATION,X ,FT.z

Figure87.- Conrparisonof sprayheightsof NACALOREdesign(nmdelno. 12g0-01)andE.T.T.design(mcdel”no.1057-04). Grossweight,3000 pounds;take-offspeed,68.7 ties pr hour.