.NATIONAL ADVISORY COMMITtiE FOR AERONA ‘6%!? WARTIME Imwll” ORIGINALLY ISSUED September 1945 ae A&vanoe Confidential ReportL*28 BIBLIOGRAPHY AND REV?EWOF INFORMATION RELATING TO TBE HYDRODYNAMICS OF SEAPUWES By JamesM. Bensonand Jerold M. Bidwell Langley Mamorlal Aeronautical Laboratory Langley Field, Va. ,. ,, . . . -.. . . ,’ “NAC”A’ ‘“ WASHINGTON NACA WARTIME REPORTS are reprints of papers originally issued to provide rapid distribution of advance research results to an authorized group requiring them for the war effort. They were previously held under a security status but are now unclassified. Some of these reports were not technically edited. All have been reproduced without change in order to expedite general distribution. L-”0 ~3 L. 31176013542205 r :19ACAACR ~Oti “L5G28 ;.. , . . * . . —.--.. . . . . . . . 8’.” TABLE OF CONTENTS . ., . .. . .... . .. . .. .. . . . . .. . 99 . . ..<..”9.9’ m...’ . . . . Page m.l q ia’e.mam. ZIWl?ODIJO!PION .q ..m-.’ ... . ..”... . .. . a.... .* 1 . COIWEW!1ONAL R’W,LSAND FLOATS . . . . . . .. . . . .-., ,mm 2 . . . “ Over-All Proport4ons and Shape” . “1 of. Flying-goat Hulls ‘... . . .. . . . . . . .. . . 2 . .?. . Mdxlmum be~ .999 *.99 3 . Over-all lerigt~: : ::: : :.“1“: .,, . . . . . . 3 . .Ove.r-al.l lp~thbeam ratio ‘ . . . ;.. . . . 3 Height”and height-beam’bqt:o , . . . . . . . . . .Skape.. . .. . . . . . ...” . . . . . . . . . . t .RwllLoading and”Leri@h-13eam” Ratio . . . . . . . . 8 Effects of load with -hullproportions “ held constent ..,.. . . . . ...”..”.. 8, .Langth-be mmati o..... . . . .. . . . .“. . . . , 9 ,Dead. Risg .”.....”. . ..” . . . . . . . ...11 Forekody ... . ....- .-... . . . . . . . . . . . . 12 ~ * BOW .-...”.*.’..’.”.”.. . . . . ..9....12 of planlng bottom . . . 14 “ . Longitudinal cuneture Warping OJ?bottom surfaces of forebody . .“. . 14 . Chine”flare’.’.... . ;. . . . . . . . . . . . 15 . . External ~lifnestrips . . . ; . . . . ..... . . 15 . . .Lonmltudinal stem . . . . ~’. . . . . . . . . 17 Flu;ed bottoms ;.”... . . . . . . . . ...13 Wttomro~@mess .“, . . . . . . . . .“. . ..19 . Afterbody .......”. .. .. . . . . . . . . . . . . . .20 Afterbodyler@h ... . . . . . . . . . . . . . .20 Angle of afterbody keel . . . . . . . . . . . . 21 . Afterbodywurplng”. .“. . . ... . . . . . . . .21 Afterbody plat form... . . . . . . . . . ...22 .Afterbody ohlne.fl.are”.. . . . . . . . . . ; . 22 , Position of Center-of’Gravity and Looation . . of Main Step’..-..”. .. . . . . . . . . . . ..22 . .Prelim3narydesign ..... . . . . .. . . . . . 22 . “Effects“upon dynamic stability” .“. . . . ... . 23 .Reloaation of s%ep to improve stability of model or fill-size airplane . . . . . . , . . 2 JMpthand Fcmuof Ma inStep . . . . . . . . . . .2 Depth of step..... . . . . . .. .. . .. . . . 24 Ventilation of’the step . . . . . ... . .“. . . 25 Step failings ...,... . . . . . . . . ...2 Plan form of step... . . . . . . . . . . . . . 22 Side Steps and Skegs . . .. . . . . .. . . . . . . . . 26. Tail Extension . . . . . . . . % . . . . . . . . . 2’7 q q q q q . . — -. L5G28 . . . . .. ..- “.. . mmm 999 9m *em *89* Page FLOATS FOR SEAPLANES . . , Over-all proportions and shape . Dead rise..... . . . st61tic8.m . ....... S.i a.m.. •.0.o.~ Effeot of s~aoing between kloR~s r . . Air drag o: floats . .... . . .. Dynadc-stability of float seaplanes . .-. . . . -. , LATERAL STABILIZERS . . . . ,-.:. &pea of lateral.stabilizer . . ..... . . . E~drodynamlc.data conce~irig,winE-tlp floats Hydrodynamic characteristics of stub wings .. .Mrdrag .. ... . . . . .9”8 9 , . ‘.; Present status of design criterions Unconventional forms of stnbllizers . , . . Emergency devices . . .. . . . . . ~ q .m99*m 99ms*m D. 9 q m,. mm q .**mmm q .:..- q . q -a q .- - 9 AERODYNAhqC AND PRCPVLSIVE C!X4SIIX?RATIONS Wing . ..... . . .*.** ., . Flaps Tail 8U;f&;S9 Propellers.. . w. * .0 Jet propulsion . . . tJNCOmNTIONAL cONFIGuRATIONS ... . Tunnel bottoms. . . .,. . ... Asymmetri”~l fleets ... . . . . Planing tatl . . . .. . . .. . Planing flaps .. . . . .,. Float-wing designs . .. . . . .Hull.-les.s designs . . . . . .. HYDROPDILS. . . . . . . . . . . .“ . PILOTING AND I?ANDLING .’. . . , Glassy water . . . . . . , I S-billty . . .,. . . ,,,.. RX4gh=water. . . , . ~ . ‘8 Reversible propellers .“. — 9 Depth O“fwater . . . . . . q q w q e m w q q q 9. q 9. q q q 9 q . q q . #lmm m q q . q 9. q , 9 9 . q 9*,9* q q 8*9 90. q q 8 q q 9 q q w 8 q 9 q q q q 9.9* ¨ 9 m q q 9 q q q q q m q 9 . 9 9 q 9 “m * q .9 9 q q , q q q q q q q q m m q a q q q q q . q q q q q q 9 .m . ., . ,. w . , . ,... . . . q Si , . . . q . . . . . . :* . . . ..*. # NACA ACR HO. L5CE8 Page -. . .. BIBLIOGilAP13Y . .. . . . . . . .s.OOO, .Os 0,04
[email protected] Hul’ls.-. ; . . . . . ~--, . . ~.... . . . Planing Surfaces..... . .. O.. . ..#. Seaplane Floats . . . . . . . . . . . . ..S0 .6 Lateral Stablllzers. . . . . . . . . . . . . . . Aerodynaml. c and Propulsive Considerations . . . . Unconventional Configurations . . . . . . . . . . Hydrofoils . . . . . . . ..o . . . . . . . ...7’ Piloting and Handling.. . . . . . . . . ..s. Impact Loads Experimental P;o;e&e; : . . , . . . . . . , Q . q **899 q m*mmm 2! d 71 72 # Z7 1 .. TO THE RYDRODYMAM132S OF S+P~S . ~d.. . Data end oonclusIons obtalned from the referemnc. ..... .NACA ACR No.. Benson and Jer?ld M. . not been ravlewed. and “seaplanefloqts.. “ & James M.lon . -. L5@2~ NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS . tatlve.: ---. . . .. ‘ have been listed Separately irltlM b. hydrofoils. @ present report. . . plan$ng. the effects upon perfonmnce of changes Im design parameters such as dead rise. Other topics discussed Include”lateral
[email protected]~~ *O the hydrodynamics of seaplanes has indicated the need for a compilation of existing scattered data... and pllotlng and handling. .. which has been prepared In an attempt . BIBLIOGRAPHY ti REVIEW OF JITFORMATION RELATINQ.-.ibllogra~y. A.1. . of afterbody keel-. . “. References on flying-boat . A bibliogra~y and a review of “informationrelat~~” . .s~ ““” .concludllqse”ct. . . .. ADVANCE CONFIDENTIAL . procedures used t~ obtain the results’dtaobsbd in. angle . .tie text may be ~ound In the references in the .REPORT .”hcwever.“ . ... depth”of step.. to the hydrodynamics of seaplanes have been presented.surfaces.. unconventional “ conf’lgurations.. Refer. . . -.ubject ha. ” . -%. of the bibliography. . “. aerodynamic and propulsive considerations.fol?ma summary of the status of knowledge pertqintig to thehydrodynamics of seaplqs and to po$nt out the need for further reaea~ch. . hulls. . Information’on experimental. enoe ?qaterlal” ~rtaining to impact loads has been included in the bibliography although tha”s.“ INTROD~TION An Increasing demand for ln~ormation. Bldwell . .“A separate section has been devoted to special problems-relating to floats for seaplanes. Characteristics of conventional hulls and floats “aredfscussed to show .. ‘The arrangement of ths bibliography in general 1s similar to that oft the text. .es In the biblloqaphy have “been correlated to piesent “inquali. and air drag.statusof tke various phases of hydrodynamic research is indicated and t-neneed’-fbrfurther research 1s pointed out . The ——. and %nry B. Edo Aircraft . “ The material presented”hare”ln has been organized in a way that isolatas insofar as practical tha effects of design 5arAmatars such as daad risa. In some instances.ll . “Acknowladgmant ’is’ ma-deto Boeing Aircraft Cov.er~o~s the functlohs of fuselage. Suydam.”Parkinson.?.Cp~oration . CONV!3TTIC’l:AL HULti AI-DFLCATS Over-All P~o~ortions and Shape .althoughan extensive treatment of the subject has not been attempted. !@ following members of ihe staff of. Diyision gava TateriQl assistance in correlating ths large amount of”data: Joe T. is in the form”of a bibliography and a brief review of the . . John W.pany. — . . .. . The hull “ofa flying ~oat”p. depth of step. bo F.. .haadfng I’Floatsfor Seapl.snecial problems relatlng to flQats ara ta~n”up . In general. of Flying-Boat Hulls .din the bibliography although tl??subjact has not been discussed In the text.-. A list of references pertaining to impact loads has’been inolude. previously unpublished data and data fr~m sources not suitable for reference purposes have been Inoluded.Important conclusions may.tha ~Lar@ay Hydrodynamics. . Fehlner.-4. Olson.. Land. . are markad with an astarlsk in tha bibliography. ..anas.. L5G28 to fill this need. King.t. Cmsoltdated T’ulteeAircraft Corporation. Jr. .odesign practida.reasons. “NormanS. Complete data and the detailed development of the. . be found In the”repo”rts listed in tlM bibliography. Douglas A. John B. Dawson.ofsaeplanes and .. under th.greports pertaining to flight tests. .appllcatlonof tk rasults of rbd~l tests.ssuch as resistance. . Properties of both hulls and floats are discussed . however. Martin Company for furnishing copies ofrOnginOerin. ” Therever possible the presentf. . Ebart.— . either for seourity or proprietary. . John E.sub$eet. J%ll. stability.—— .-flotation gear. and landing gear..13M.ead’i!lg ‘fConvantlonal H’ulls”””ati Floats’!and.Roland E. . Reports $hat are not ganarally available for distribution.. and The Glenn L. .. 2 . .. and angle of aftarb@y keel in preference to wore general Subjaot.. . NACA”ACR NO.ugder the t. .ls. .ce. The over-all form is important . It is possible. It.of “the hull ~ requirqd for aooommodation and aerodynamic oonfiauration in order to provide sufficient spray clearanoe for the propellers ati aerodynamic surfaces.il Hetght and height-beam ratio.proportltins . somewhat b~ the buoyenoy. the forebody length-bear~.affeotcf such a variation on the aerodynario drag is Included with the hydrodynmnle effectd under ‘Hull Loading and .a flying-boat hull Is determi‘bed.rat~r.=all form.. .that.ls possible.. The beam loadin~ is properly regarded as a very important criterion ond mqst be selected to suit the intiehdedserti.ngint.. to vary the ratio for the same design and still maintain tti sam degree of seaworthiness by varying the beam loading.Length-~am Ratto. and the size of the tdl aurfaoes.over-”all .ratio. to use different heights for different beam loadings and still maintain the same degree of seaworthiness. “ ““ “ “ Over-all length.. In contemporary hulls.:prdporttons harmonious combination of tlm.for .length of tb forebody dation ahead of the cehter of gravity.-Theover-all lengthbeam ratio is fai91y well determined by the type and oonfiguratlon of the”airplane. . ! NACA ACR Not L5G28 3 and shape of.pultfrocma -.r~ and for adequatg se~wcrthiness underway plus tl’mpredetermined-distance from. The .o oofisiderqtlon its requirements -. the over-all. however..thaq by tqing “.length is usually greater than the sum of forebody a@ afterbody lengths.designed’by tald..~f .sekworthiness~ tail-lengths sto. A hull is””best .r”equired Wd In transport airolanes by the width required for accommodation of the pay load.qaqh $’umticm or .=. . Over-all length-beam ratio. Most present-day wultienglne flying boats are characterized by high beam loadings combined with high height-beam c - 1 — . however. spaoe for adoommodatio~.. The additional length is”the tail extension. ahd ‘Qhtip6”s bf tlm various components designed.The height.the center of gravity to the tail surfaces.—.hull . comblnatioq of f’umtions. ” required for aceo.a :hfil re. to fit the requirements Into a preoenoelved over.The maximum b-eam.The over-all length of the. M&ximum be~. . in Itself maln~y In connection with tls fuselage aqd flotation functions rather than with ~~e detally!i hydro” dynamic charaoterlstios during potion on the mater.. . is ap~e up of the.. . . . Tests .35 is at a . .ratio ofl. Hydrodynamic..the ovgryall proportions and.tbased on. u . Shape. .“: ... In geneyal.the flow “ . . .61OP o tw~nodels of flylpg-boat hu\ls.. . .chshow a similar trend (reference 7~).th although the drag actually ~ncreasea (reference ~3). .(a)as curves of drag coef~lcient based on frontal area plotted a~ainst height-beam ratio. 1s one example in which low beam loadin~ Is combined with low height-beam ratio of the”hull. however. . systematic variatio~in height-beam ratio cmrblned with a~propriate values of len@h=beam ratio are required to “ determine yhether there is.. . . .m mm -m-m .th~l huva been determined. .theLa~ley 8-foot high-speed tunnel whj.2 w~le t~ trend for the’streamline body is reversed. and Clark (reference 18). Below the chines the shape must have suitable hydrodynam~c characteristics . .same data presented in f~gure l(b) as c)urvesof drag coefficient based on the tyo-thirds power of the hull volume plotted against-height-beam ratio.wing being carried on a pylons yet ~s considered exoep$lonally seaworthy.on. .. . s -m m. . . . the. .. of:’waterqq a~~ and for ease of constructt. . . . . ~ . The.. L5G28 ratios.be re~sonahle to pxpeot that the mlnimm’drag fhr a given volume would occur near a heightbeaw..M6K!. 8. along with similar data from tests of a streamline body “in.4 NACA ACR NO. The PBY-5 (Catalina). . ..tests 0$ a related fsmily. “itwculd..inimumof ~qterfergnc~ t~. . .. .volume for . .in.O. .miniru~near a bsight-beam ratio. . .have concluded from . . .dinmnsions of. the drag becomes a function bf the detailed shape. .an cptlmum height-beam ratio for a giveanclass of airplane. howgver.. . -. .. . .ch tunn. these data tkqt hl@ values of height-beam ratio are p-heferable.. but”ot@rwiae” shbuld be srooth ~d fair in three “ dtme~~io~s f~~ tke ~. ..mod~l. .hav6 shown that the drag coefficient based on frontal area decreas~s with an lnorease in the height ~f the hull for a given beam and le~. . The data are shown in figure l. . . ‘.....8 . Coortibes. The drag coefficier. .. . .of poweredodynamic models having . . .tQ& Leqgley pzopbller-resea.. and some authorities conclude that this combination is preferable from all standpoints (reference 18). . . indicate a different conclusion. . .of 1.- . . . . .. ..06 q Model 84 streahllne body . .ktre%line . -. . “f’.i.024 ..:.. ... =-. . g: —. . Model M.. . .entBas”edon ... .. . ‘ “.. . ..gura lo. . r ..:. . . . . . . .6 “ . . Drag coeffioi. . . . 9 . -. .06 “ ..35 flyi&b~ht. A“ . . . . . ‘... @II .m m . . . .. : . . .. .. h . . . . . . .. .. ‘ ““. .. . .‘Vartationof drag ~oefflcient with heightbeam ratio f’orflylng-boat ”hullsandstreamllnebody. . \ . . . . . ..../“. . . ... -.. . : .. ox -. . -. .. . . . . . ... ..: .rlyi&’tiat hill ... — 5 -.( volme )2fi IY1. . g . .. .. . .. >. . .. 4’. . I 044 .. .—. .. . . . .8 ~ 1’. . - body . . .. sg coefficient based on frontal area... .. ... Height-beam ratio (b) . . . . :.. . .... . q .040 I Modelll-Af@ing=boat hull . . -. . ... k. s’ & “ .. ...—. . . ._ — + %’ “. ._—. .. .. ... . . ..“ iO&. I ..7. . . .@ACA ACR NO* L5G28 94 -. .. . . . .:. . .f’oundto be 0.etiondrag coefficient .ggear ts given In reference 7% In whiblithe mlnimti drdg coefficient of a streamline hull was shown from tests in the Langley &foot high-speed ttmnel to’be ab~tit20 percent greater than that. 23.from.. A similar comparison was made in”reference 18 which indicated that.. The mlnim~ frontalarea drag.. frontal area Is estimated to be a reduction In minimum drag nf 21. Warping a streamline body at the stern is shown in reference 79 to have no adverse effect on the minimum drag but increases ths angle of minimum drag as would be expected.coefficient. .tb minimum drag coefficient was 22 perc~nt greater”than that of the wanped streamline body from which it was”derived. the increment not chargeable to s~n friction was theref?re 42 percent of the total.whic~It was darived.. presumably at the same engle ot’attack.. As an ‘lndlcat~onof the relative “cle~ness’t of flying-boat hulls. warping the tail of the streamline body is said to increase tk drag 13 percent.. for the hull considered. m. however..of a.as measured in the LW+gley two-dimensional low-turbulence pressure tunnel (reference 70) was. In reference 43’the beneficialeffect of a rounded “deck for the same. In reference 18.056 at the saw..O?2as”compared. .(fig.rbntal-area@rag coefficient of. ..6 m. . NACA ACR NO. ..O. The best hull with a tall extension had a minimum f.. . . Hartman”(referencp 43) compared”their drag coefficients with the drag c~efficient pf an airship hull at the satie-Reynolds number. and 79 the general”pre’kdse is advanced that the best over-all shape for a hull is one for which the departure from a streamline body of revolution are kept at a minimum consistent with hydrodynamic requirements.l. and 26 percent.ofeither the straight’or the warped streamline body .. 2).. A closer estimate bf increment c@r@eable to the function of the”hull ’as a landln. “abut “L7 percent. of 0.-. L5G28 -.. “Increasing the height of a wellfaired bow has cnly a small adverse effect on the drag. .with the airship drag coefficient of 0. .052. .080 as compared with .very clean hull.eRe~olds number..$twould-be possible to reduce the drag of this hul.. ”henee. 70. . In references l&.a~skin+ri. Increasing the height of the stern by warping the basio foni but holding the afterbbdy position fixed has a larger adverse effect (reference 79). . if all practical considerations are neglected. .-. . *-+ . ...% . . . . .. . 1 . .. -.. . . . . .:. . . .... . . . r&328 . . .. . . .’ . . .. .ACRHO. ““:””. . .. . . .. :. . -:. . . . . .Conventional flyin~ boat for transport sertioe wl. . .. . . Feet . . . . . ‘. . . .. . .- — —. . .“ “- —. .. .7~ I . . . .-.. ... ’... . . . .. . #. / . .. .. .-.. . . . . . 2. nJ. . . .. % “. .... .%. . :.. . .— .... “ ... . .. .. .. . . . . . . .1 . . % . . . . . . . .. . . . . .. ... .-. .. .. . Fi&e. . . .. ... .“.” . . . .. th hull designed for low air drag (reference 70). .. . . .. “1 . ? ..”.... . . . . . . “~ l?ACA . . .. ‘. ..: 7 .. .. . . “:. .. . . . . .. . .: .....+-+ ‘ “t ‘ . . . . .. . . . . . . . . . . . . .— . . . . . ““”5!?. .. 120.). . . .... Effects af load with hull prouohtions-hsld @onstant.irrensiono Load coefficient provides a good scale for the load on hulls having comparable lengthbeam ratios and for any hull in the planing condition. .and @ngth-Beam Ratfo - 8 The loading of a flying-boat hull or a seaplane float is usually expressed-in terms of load coefficient CA. . whtch is based upon beam as the characteristic d. . respectlvely..for minimum drag or forms having excessive surfacemqrp~ will n~tz in general.r.. .’.most of its s+gniflcen. .. of about .. -.dlength is a depetient variable. It is necessary to consider both variables in discussion of the load-carrying capaoity.bow of the hull fs watt~d. ... however..oftheir ‘hydrodynamicadvantages (reference 70). -> . . . ~f the afterbody must bq%made approximately in proportion’t~ those of the forebody. (~g~ 2“show? ““a flying boat of conventional arrangement for transport service with a low-drag hull havjng suitable hydr. . The Increase fn drag attrtbute~ to the windshield 1s small.” . in whioh wettb. The length-anti beam of the forebody are considered the most important dimehsi”ma because tka di-mensions.~e in the comparison of hulls of different length-beam ratios.“ dynamic charact%ifWtics for a. .~.000 lb.. .*-. .in numerous lave been in~a~ed The effects of load ~ general tests of fl~ing-boat hulls an~ in overload tests o. be desirable fo. At ..ific~esigns..high-pe~forniance airplanes regardless.. The added drag of properly arranged chines and “stepsbecoues of the same order of maEmitude as that dup to roughness and unavoidable protuberance& on “theactual hull.1OW speeds. .. . . .fmost speo.~~ . Radical departures from the form. load coefficient Ioq&s..qources show . . for the’ ‘th”ree mollb”l 8 considered.gxoas weight.. Data from these. Beoause of the close rel~tionsb~p between load coefficient and length-beam rat!o.. The available data on tie effects of proportions and shape indicate that oareful design and attention to the shape of the hull are-essential in order to keep the parasite drag at a minimum.. Hull Loadln&. .or the performance of hulls at low speeds. when t. .0975 fpr hulls with excesstva spray. nondimensional. CA: =’k+: “. the upper and lower trim limits of stability (d) usually.. ~ln ~nal~~ls sl’owsthat the load capacity of a hull of conventional propo~tions varies with the i’lrst~ower of thq. . In references 17 =nd 18 it. . Increasing -. :. . 1 . .decreases thk rAnge of stable locations of the center of gravity (e ) increasee dlff’icultyof directional control at low speeds (Several. .forebody.dy.— .oases are known In which the load oi’a flylng boat has been litited by directional instability. ‘b is the beam... 2 . assumed that uniform seawort~ness:may.length of farebo. .th load coefficient .. increases the 1%1. .: (a) reduces load~resist’ante ~atlo speed (b) inorease”s . by.0525 for hulls with lightsprky to 0.eflying boat may be detelmlned by the folloting expression: ...+:ht and intensity of spray Ienpth-beam ratio.. . . . NACA ACR NO.r). . A/R A~R at. . .. and ~k Is . .-.was. . .ned.hump at speeds near get-away (o) raises bo~fi. .. be mainta~. .critetion. .r . .ad proportions. . . where Lf is t~ l&th o~. .A 6ritorion. The maximum gross-load coeffl.n~the grossload coefficient CAn af a fly:ng-boat hull to the lengthbeam-ratio of the forebody F. ranglrigfrdm 0.. . -.) (f’). .a.cientfor the hull of a multlengln. :-. .asbeen established by snalysis or ths snray characteristics of existing flying boats (reference 69)..beam qnd the second power of the. ‘ “ .relat~.varying loading so . L5G28 -- 9 -. . the effects of load on t@pmd’ormanceo of flying-boat hulls of oonyentional shaps.. 0. “ When the load of h hull is held constant and the length-beam ratio is varied by changing length or beam.. indicates that when CAO is proportional to (L~)2 .. of notes on observations ‘of spray. m variatlons”of this type. .e e~fe”ctsof lehgth-besn ratio 16.. . . ‘Fr6m data In these r... :: :. . . has also been supported”by Davidson &d’Locke (reference 20). . ‘ ~AoCC ~ ‘. “mese references indltie data on spray with: out power.at b. 20. C:AO proportional to L/b gives very conqenvati~ iQading. The approximate relatlonsh~p .5 to 10. on the trim llmits of’s~ability are included in refer= efice20. . the-effects of increasing length or beaui “are in the sme direction as those ofreducing Ibhd’without changing ditiensi”ons. . the effects of.. “ W.. 1 (reference 8) have shown that holding ..general tests. . and 143. .: ..11 I n 11111 1111 1= s I -m I s s 10 ‘“~NACA ACR NO.. . may”be abtainsd: ““ .data from systematic Investigations”of” length-beam ”ratio tireavailable in references 8. e . . in reference 49. Resist~ce. .. have been reported .tie hull .The effects of increasing the length of a powered dynamic model’.ports for otir-all lengthbesm ratios from 5...&nd ~3.: . . but no systematic-spray investi$afloqs nave been made with powered models of dlfferetit length-beam ratios. . . L5G28 that the draft “of We ‘malh“stepat rest remains a con.. 0 . Tests made in Langley”&nk no.on the basis of conclusions reached in. 17. . :. ~ CAOW () ~ &z . 20.length-beAm ratio are usually obscured by the effects of changing the size of the hull. 91. Andlysis”of”data from references 8.. . . “.“atant:proporti on”of the Iensth of the fo~body of.ir~values’of L/hi . the followlng expression . L2... “ . . . There Is some Indication ~. . .. of 20° to 30° probably repdesent the best . ...t.. . . . .amecharacteristics are not -tipaLred. .. Data on the effect of dead rise are available from tests of hulls and floats -(references11. . . “ L (b) increas~s resis. . .- _ { —. . . 11 “.. 1L6. . ~eqe data are In general agreement an mo”stM the ef$’~ctsof’ dead fiise... .. . Angles within the. about the same for a length-beam ratio of 9 as fop the”.rage .to thb fore= ““.I. . .. the angles 01’dead rise measured ad~acent.15°to 5@ . : basic .Q28 . . f . . -— .o . . .L”’. . . . that the ratio of ovwr-all length to beam beyond wliim ....~peed~. . over-all Performance. . .. ..’.ue of 6. the XPBB-1 airplane ZndZcabed. . Dead. ‘1 . Some recent Britl. . of. .Iengthkbeain.I NACA .. .: from thb ~roportlons “of.. .5 . trb at the.on”.~..—.~. . the’satie’ aqalysi~ -thqletig+~=be am ratio “. (a) ~has Ilttle effect. .. 18. T& be8$ ..s cm . . ACR. -. M’ ‘length: befi”ratlqs”are”“increasedfrom 5. ence 20). lb? for opti.res ls~!ancech~racteristica depetis upon the:” lines of the hulls considered. and 119 ).. the .. 43. (d) raise-s. .It has been ~hfi “that the”stable . .vd.L5.. .e at speeds.nhm . .Rise” . 22.. “ Foti’mop”t present’d”ayflying .. rmge from . . . ‘ . to 10.shdesi”gns. (refpr”-. . :-..tilt.’... body keel near the step lie between 20° and 25°. .. . stab~~ity. (e) reduces the impact loads ‘. .. 140.b”oats of fier”ic~ desl’~.lmlwer tr”& .. —. . (c ) iti”c&aa~ pQsAtve trimming moment “~at plklng.co”mprornise fofi .. The prlnclpal advantage of high length-beam ratio a~pears to be that of reducing lengthbeam product and thereby reducing . that the stable range of center-of-gravity locations “was“. .hu& resist~c? ‘in the-:. . .. Inorgaabd~ . no furthor gain is obtained in hydrodynamic characteristics Is between ~ and”10’(~“fedences 17 “and18). . . . . employ an angl~ of dsad rise of as much as 30° (reference 35). . the spray an~ resls. . .. the size of the hull. .h~p decreases as .the angle of dead rise . . “ Recent te$ts of a faintlyof models de...Is..tuo. 109. ““ .range of . 23.. ratio. and 254) and from tests of planlng surfaces (references 108. . .above hbp. : trimi” is reduced WIth Were aslng length-betsm ra~lo:. .r$ved ‘~ .. 26..5. Increasing.. .3. For a hull that is developed about a streamline body of revolution. ..@li&ved” that inc. fi general.Coinpromi9bsin the “shape of the bow are frequ~~ly-made to accommodate bombardiersl” windows ““” or armament in military designs and may be made to . . . air drag. . . 3.“ MACA AOR NO. btitreference 22 shows a “sltght lowering of the upped Itiit with an increase.. with a minlmwn of departuzze from the best aerodynamic form. 12 .dynamlcmnodels of a flylng boat (reference 23) indicate. that the landing stability is improved by increasing the an~le of dead rise from 20° tO 25~.eadrise on air drag is ltilted”and is not in agreement. Model tests of a flying-boat hull with:slightly arched cross sections {negati* angle of dead rise) sho~d “ excellent spray characteristics and low resistance (reference 3). “Increasingthe angle”of”dead rise within the range of 15° to 30° generally reduces the spray but tests with planing surfaces (reference 119) indicated ~ increase in spray with increasing angle of dead rise. certain principles should be followed in order to provide seaworthiness and resistance characteristics consistent with operational requirements. favor seav~orthiness. L5G28 . . “ .“.. the air drag will be at a minimum if the chines are located in .of angle of d. and 30° (reference 140) show increasing air drag with increasliig apgle of dead rise while a British compilation of data (reference 1S) indicates that air drag deci”eases with increasing angle of dead rise.ise. as indicated in references 23 and 108.. ‘ from”20° to ~Oo In ahgle Of dead r. ~Forebody Bow. however. It ls. . or simplicity of construction. Z5°. ..) . Tests ”tif pbwered. . The av~lable information on the effect..1’eaqing t&e an”gle”of dead rise ~ raises the upper trim limlt of stability. . Langley wind-tunnel tests of three seaplane floats having angles of dead rise of 20°. (See fig. planes passtng through the-axis of the basic body of revolution (reference 79). .. . . . .. . .. “ofre~olutlon . . . . . .. . ...- “. 1. .... . . . ....-. . . .“ .. .Full developed about a streamlinebody of revolution. .. .. . . . .. .“ . . . .. . ..‘ . .-. . . . .. . Figure 3. . . ~~ 8 Of warpqd streamlinebody} I . RI 03 . (mom refere~e 79. . . ..... Axis of’: st~e”drlln :. . .- . ..— . .. . . ... . . . .} 1 . .. . . .. t .body .:. “. . 4- (2) Mcreasing the lifinenesst~’ of the bow below the chine reduces bow spray (references 55 and 79)... ..the hull (references 68. . .—. . (4) Rounding the‘chines (In cross’: section) at tie bow will severely increase the bow spray and will reduce I the air drag at large or low angles of’.5 beams forward of the step in or$er to obtain satisfactory spray. . . . - _ ----- . . have no longitti~nal curvature for some distance forward of the main step. The more significant eff’ectsof longitudinal curvature of the planing bottom near tie step are: (1) Convex curvature of tQe buttiock~causes negative pressures at planlng s“pe6dsthat may significantly reduce dyrmmic lift and tipair the efficiency of. (3) ~creastig the heIght of the bow increases the air drag (references ’79 and 139). 13G28 ..Systematic Warping investigations of warped planlng b Ottoms hating straight buttocks have been reported in references 22 and 55. . 90. . resistance... c ~“ “ (3) Concavtty that is.. “ .— I NACA ACR HO. At angles near those ror “theminimum drag of a“suitably designed hvll. I .speeds (reference 79). .attack (reference 79). . rounding $he chines has no significant effect on the air drag (references 58 and 79). . (1) lhsuf’ficlent buoyancy forward results in low trim and exoesslve bow spray at low.Ioqallzed near the step in a length of the”order of one-half the beam or less may cause extremely severe lnstabillty~(references 12 and 61).. mm . .1 mm mI s UII - mmm- mm= mm= .fchanges in the shape of the bow are summarized as follows: . of’bottom s~faces of forebody. . (2) Long~’tqdinall$ concave buttocks Lava little effect on hmp resistance but reduce the resistance and volume of”. Ef’ fects o.. and-stability characteristics (reference 70). --.. . and 91). . . A rough rule often quoted 1s that the buttocks should be straight and parallel for about 1. ..thesnray~at high ‘speeds (references 67 and 119). level but has little ef~ect on the spray where the chtie of’the model is below the water level~ Chine flare has little effect on resistance at the hump and at speeds near get-away.lt 8 percent of the beam and ending with a horizontal”or slightly downward dlrectlon at the chine.. but it 1s also shown in references 55 and 79 that by oonflnlng the warping to the forward portions satisfactory bow spray oharacterlstlos may be obtained without compromising the planing characteristlos.resls$imce at me. Chine flare reduces the height of the forward part of the spray where the spray leaves the model above the water. 98.. The bow spray Is fi~roved somewhat by increased warping. lowpr t@m ltmlt of stabi~~t’y=but-” “ the ohange at speede just” hybrid @ hump ”ls””relatl”tily smaL1.lqrerllmi~. ~re as$ng the. 40..lbwe~lng f t4p trllntrhck.. which may result in a6h&ngeln the s!able”range “of center-of. 43.“ gratity poaitlons. I&28 -. ~e.NACA ACR NO. however. External chine strips. as shown in figure 4.i.ofa hull if the chined are located approximately along the natural lines of air flow (reference 79). however.Chine strips may take ths form of relatively in projections extending outwa@d or downward from the chines (references 23. wprping’ticfieasesthe. Strips are sometimes incorporated instead of qhlne flare to improve the spray characteristics without tivolvlng complicated construct on.hump and at high speeds. but the addition of ohlne flare.. is fo&bc&y%~ij&o~ (de&”:@se~ &&easimhg”” toward Iihe”bow) low6ra””the..“ -Thislowering of’t@~. Wide variations in the width. causes a slight reduction in restst~ce at speeds just beyond the hump.overloaded hulls or hulls with insuffiolent chine flare. external ohlne strips of either type are added to Improve the hydrod~amlo performance of. oause relatively small .lower tblm llmit lb “ -:a:ccomp@led by”a. radius. . and 256 ) or of sponsons. that Increase the beam and have a depth approximately equal to the width (references 49 md 60). .slwered slightly but not as.have shown that good spray characteristics may be obtaine~ with flare on the planlng bottam confined to a width of aboi. China flaz% has llttle effect on the air drag .rnuchas:. W~ing”&: Chine flare.differencesin the spray or resistance characteristics.Teats of a large number of variations of chine lare ~referencd 9). m most cases. by reducing t~q height of the chines above the keel. or final downward angle ot the flare. . 76. the’ .upper trlrnllmit. 5) have shown that “verticalspray str$ps -pro@ting. .. ... .“ .:! . that such strips incrb’asethe air drag:: of hulls ‘by’8‘to120percent (refe”tiendes ~. .the bow. ...’ . 45. . .use only when it 18 neoessarj to .heavily loaded hulls (references k9 and 60).loads.... . lLO.” .. . . Spon80ns on.” & “+--l .. . + J . . . . . .(fig”.. aotebi”qtios ‘$nd clausesome reduction in. . . .reslstanoe (ref’eiwnces. . . . .. . .Sponsons extending outward and downward. .. . .. .the bow spray:at hea~. .Recent tests (refemence ~4. q . mnd-t~”nel tests hg~e” shown~ however.. .... 16 . “: .-car~i”ng capacity of an existing hull. .. . .” .” Flgure”~. . . O&b “.. Like the thinneh chine. .tkk .from $he . .p... . “Model.....:”. ‘“”””” . 98.“.... 1. tests h~ve indicated. . .“. ..~ tiowfiard”an@lesof 1“0°to h50 improve . o++” . . . .. . . a~d 256). forwafid. .1chine. .eroent. . .“ . . . . . . overload capac!. and 256) . .“ .. .-size .aid tke .spray. . ... . . “ .a%out.aid full. bem.3 percent of the beam dowm+ard... ... -. .. . Figure 5. . ths””sponsons si~lficantly incrsase... .that sponsons greatly increase the. L5~8 . .’”5)” are about as effective as spon~ons ih .increase the lbad. .“.. 3 . portion of t& forebdly have been used to control thb spray of. 1. .-.tyof flying boats by reducing. “. ’:.“ . . . ... . ..strips. . .S@ay strips extendin~ vertically downward from chine. r+ . . Strips having s width of about 3. . ... ..ohar~..the air drag”and afi suggested”fcr””. .l?ACAAGR No. . .. .. . .. “~se strakes had ne~ligible effeot on-the resistance at the hump but caused some reduotion in resistance at higher speeds.Arran ement of longitudinal steps for NACA model 20f .tlon regar@. ~gure . —- — . 6.)..ng the air drag of vertloal strips Is not available and th valub’”of-” retracting this type of spray strip is questionable. 1 percent of beam. Longitudinal steps. Inform@. One model has been Investigated to determine the effect of reversed lap strakes. . inoreases the resistance at low speeds and decreases the resistance at speeds near getaway (referenoe L. This type of bottom. The spray from the model with lap strakes was more finely broken up than that from the parent model but had about the same volume and height. Depth:of longitudinal steps.Im@tudlnal steps oombined...NACA ACR NO. in contrast with a conventional V-bottom. . 15G28 . . Re~istance tests were made of the model complete with a conventional afterbody. The effect on dynamic stability has not been investigated. Apparently no data. “with flat surfaces having little or no dead rise were used on the forebodies of a number of flying bats som years ago. similar to the cllnkerbuilt arrangement of’ship planking (fig. added to a planing bottom of’the fnrebod of conventional fom and proportions (unpublished dataY . 17 controlling spray..are available regarding the effect of an arrangement of this type on dynatic stability. 6). .... . L5G28 ..configuration the strips had a cross-sectional area equivalent to an increase in depth of step of less than 1 peroent. ~ was required for adequate landing staMlity without the longitudinal steps. .ofthe step. . — — —— . .of the beam so that the combined crosssectional ~rea of step and strips was less than half . Figure 7.-— I 18 NACA ACR NO. With this. ..’ Another variation of longitudinal steps has been tested on a powered dynamic model (reference 61). I 4 . . . .-.’ . .fl&ure 7. !t!hls modifi”oatlonoonsl-stedof a-triangular strip on either side of the planing bottom ‘forward. . It was also found that longitudinal steps of the same type but of larger SIze provided adequate landing stability with a depth of step of as little as 2 percent of the beam. . . . ....5 percent of th6 beam .. . as shown In. .Triangular strip added to planing bottom. Longitudinal steps of the dtmenslons shown provided adequate landing staMlity when used In conjunction with a depth of step af 5 parcent “ofthe beam... A depth of step of. I .. . 1.11.. I T g . during t.. at the hum~. The use of round-haad rivets inoreasas the total atr-plus-water re~istance of a singlefloat sgaplane less than ~ percent at hump speed but as much as 25 percent at hi@ speed. it Is found to be 2 percent higher at hump speed and 8 percent higher at planing speeds than that calculated by taking Into acoount the.-.-. -.. Bottom rOU he9S. f ITACAACR NO.. If the total resistance Is calculated.Model tests (references 25 and 264) have ~ndlcated that the substitution of a fluted bottdm (fig.— .——- --— —- . q Fluted bottoms. of fluted bottoms.. 7. and round (reference 101). brazier. 8) for a conventional V-bottom causes some reduation In spray and a reduction In resistance at high speeds but causes little change in reslstanoe at low speeds and Chin ‘< I Ohin I I -r Kee1 \ r----! I 1 ‘Keel Figure 8. The order of rerit of commonly used rivet heads in relatton to low water resistance is: flush countersun~ ovsl countersunk. full-size seaplane model. .lation.. The effects of flutes on dwuzmic stabillt~ have not b~e. L5G28 19 . — .e with rivet heads Is directly proportional to t-nehei@t of the rivet head above the surface.!. Considerable difficulty has been experienced by service .Exaples . ‘ “.. by Froudeis law.ake-offsand Iandlngs. the increase in ~th a ~ 3*5 total water re”slstanceoaused by round-head rivets varied from 5 to 20 peroent at hump speed and from 15 to 40 percent at high speed.effeot of scale on frictional resistance (referenoe 136). The principal advantage of flutes appears to be that of Improving the structural efficiency.The Increase in friction ooeffioie~= +p a~~~d—surfao.ninvestigated but no advers& effect has been observed on full-size application.. the area normallyrequired for sufficientyent$.~-----.. . . —— .--- —--- NACA ACR NO. 15G28 organizations In maintaining watertightness with flush rivets of the type currently in use. Afterbody A primary function of the afterbody Is to provide buoysnoy and planing area aft’of the center of gravity so that trims at rest and at low speeds are acceptable for practloal operation. At speeds just before the hump and at hump speeds, the dynamic lift developed by the afterbody planing surface is one of tlm principal foroes that controls the trim and, therefore, the water resistance. At planing speeds, the spray that strikes the afterbody increases the water resistance ati ohanges the trimming moments. Take-off end landing Instabilities that ocour at high speeds and trims are associated with the positlpn afi form of the afterbody. n general, changes in the afterbody that increase the afterbcxly clearance increase the static trim, increase the hump trim and resistance, decrease the high-speed resistance, shift the peak of the lower trim lim.ltto lower speeds and higher trims, ~d also raise the upper trim limlts. The trim tracks (variation of trim with speed) are shifted In the same direction that the trim limits are ohanged. In tests at tb Langley tanks, no combination of conventional forebody and af’terbody planing surfaces has been found that eliminates either t~ lower or the upper trim limits of stability or that suppresses the upper trim limit at high speeds. Afterbody length.- An increase in afterbody length lower trfi limits of stability at hump speed lowsrs and lowers the upper trim limits (references 21, 22, 23, ~8, 61, and 100). For a given depth of step and angle of afterbody keel, landings are more stable with a short afterbody than with a long afterbody (referenoes 148and 6~ The depth of step required for the landing atabil!ty of a model with an angle of afterbody keel of 6.2° was approximately 8 peroent beam for an afterbody lengthbeam ratio of 1.7 and approximately 13 percent beam for ‘an afterbody length-beam ratio of’3.2 (unpublished. data). An inorease in afterbody length without any change in forebodv length decreases the hump trim and reslstame (references 21 and 22) and may sometimes increase the spray in the “propellers. Experience has shown that . ...- _ -.. ..... .-— I VACA ACR NO. 15G28 21 . deoreaslng the
[email protected],duces spray -in.theregion of-the . flaps “(reference23). The tests .desortbedin reference 23 Indloated that an increase In the length of the afterbody decreased but did not remove the directional instabi~ity at low speeds. ~le of afterbody keel.- An increase in the angle of afterbody keel raises he lower trim llml.tsat low speeds and raises the upper trim limits (references 21, 22, 4~, 93, and 100). For a given depth of step end length of afterbody, landfngs are more stable with a low mgle of afterbody keel than with a high angle of afterbody keel (reference 48). The depth of step required for landlng stability of a model with an afterbody lengthbeam ratio of 2.7 was approximately 9 percent beam for an angle of afterbody keel of &.80 and approximately 14 percent beam for an angle of afterbody keel of 9.3° (unpublished data). For some comparisons involving changes in both depth of step and angle of qfterbody keel, the angle between the forebody keel and a line joining the step ~ sternpost, called the sternpost angle, is a useful parameter (reference 22). In tests of’three series of models (references 1, 11, and 79) an increase in angle of afterbody keel fYom’4° to 9° increased the free-to-trim hump resistance approximately 25 percent and the best-trim hump resistance approximately 15 percent. Low angles of afterbody keel decrease the static trim, increase the tendency for spra to come over the buw at very low speeds (reference 55 T, and decrease the hmnp resistance at low speeds (reference 11). Aerodynamic drag measurements (reference 43) hdicate that differences in drag are practically negligible for angles of afterbody keel of 6° or less. At larger angles the aerodynamic drag Increases appreciably. Afterbody warpln~.- Effects of systematic ohanges ti warptig have not been extensively investigated. Frcm the more or less isolated lnvest~gatlons that have been made the following results are of interest: (1) Warping in a manner that decreased the angle dead rise at the sternpost reduced the hump trim and resistance (reference 79). of . . - (2) Warping in a manher that Increased the angle of dead rise at the sternpost from 0° to 30°, with straight .— .. .—- .. ._ . ., . . 22 NACA ACR HO. L5G28 buttock lines, ratsed the lower trim limtt at hump speeds and raised the upper trim limits (references 21 and 22). ~creasing the angle of dead rise at the sternpost of a dynamlo model from 20° to 30° ral$ed the lower trim llmit at low speeds, did not affect the upper trim llmlts except at loiispeeds, and sltghtly reduoed the yawfng Instability at speeds below the hump (unpublished data from Langley tank no. 1). (3) mere-m the angle of dead rise to a maxhum near the midlength of the afterbody has not signlfioantly affbcted the landtig stability of models (references 23 and 61). It should be noted that tests of a full-size flying boat (PEM-3) with an afterbody having this type of warping showed satisfactory landing otabllity with a depth of step of 5 percent of’the beam and a load coefficient of 0.8 (reference 34.). {’ihether the warping contributes to the satisfactory characteristics is not yet established. Afterbody plan form.-.The plan form of the afterbody appears to be of secondsry slgnlflcance In resistance and-por~oising charactertstlcscomfiared with the length of afterbody, angle of afterbody keel, and angle of dead rise. Changti.gfrom a pointed plan form to one with a transverse second step had no significant effect on the hmnp resistance (reference 9), reduced directional instability at speeds below the hump (references 23 and 73), and increased the air drag (reference 18). Xodifying a pointed afterbody to form a cusped plan fozm reduced the unstable yawing moments at speeds below the hump (reference 10). Afterbody mine flare.- Afterbod~ chine flare increases the dynamic llm of ti afterbody and reduces both the hump trim and hump resistance (references 21, 22, and 79). If the spray does not break clear at the after- . body chines, suction foroes may develop that Increase both the hump and high-speed resistance (reference 70). Under these circumstances, the use of ohine flare Is advantageous and will reduce the Sandin& instabilities (unpublished data). Position of Center of Gravity and Location’ of Main Step ence Preltiinary desipn.- It has been suggested (referthat he center of gravity be located on a line NACA ACR NO. L5(328 23 passing through @ step and Inallned between l~” and 25° forward of a line normal to ~~e forebody keel. Tests “of powered models of current design indioate that a range from 10° to 20° may bd preferable. If the plan form of the step is other than transverse, the centrold of this plan form may be used”as an equivalent looation (referenoe 100). Referenoe 70 suggests that with the airplam approximately in a stallsd attitude the oenter of gravity should be directly above the step. For airplanes with abnormally high angles of stall, the maximum trim expeoted In landing may be more applicable than the trim at stall. Effects upon dynamic stability.- Variation in the position of he center of gravity has negligible effect upon the trim limits of stabillty (references 100 and 106) but has a large “effectupon the trim tracks and consequently upon the probability that porpoislng will be encountered. A forward movement of the oenter of avlty lowers the trim track, and lower-limit porpoislng low angles) may be expected at speeds just above the r hwp . An after movement of the center of gravity raises the trim tracks, and upper-limit porpoising (high angles) may be expeoted near get-away, Instablllties while on tk water may therefore limit the range of positions of the oenter of gravity that can be used for take-off. The rest forward posltton of the center of gravity at which a flying boat can operate is generally limited by aerodynamic c requirements for control and hydrodyn&ulo requirements for stability. The main step Is best located so that the hydrodynamic requirements for stability are met at the most forward position of tk center of gravity at which the flying boat will operate. The main step must be located so that, with the center of gravity of the flylng boat at its most forward position, lowerllmlt porpolslng can be avoided ?iuringtake-off. In the event that porpoising does occur, positive trlwmlng moment (up elevators) should be available for increasing the trim to angles above the lower trim limit. Tkds prooedure has been used for locating the position of the step during tests in the Langley tanks (references 10, h7, 60, 61, 63, and 100). to impro~e stability of model or model or I@t tests indioate ard position of the center of gravity wh~ohlses%:le for take-off does not coinoide with the position required from aerodynamlo considerations, the Relocation of ste The factor 1. 71. and 4. 78.3 is tlm ratio of the gross load of the afrplane to the approximate load on tb water at speeds and trims at whioh lower-limit porpolslng 000WS. .lirit at low speeds.— .l!t by relteving these suotlon foroes (references 47.— I 24 lWIOAACR NO. . it Is desirable to favor a forward position of the step if further modifications are anticipated. 22.. 93. If relocation of the wing Is lmpraotl. An Increase in depth of step increases the landlng stabi.. Inorease in depth of ~tep Inoreases t~ hump trim and resistance and deoreaeee high-speed resistance (references 7.. a fprward movement of the step results In a reduction in the depth of step that may impair the landing stability. 21. An after rovement of the step results in an increase in the depth of step whioh may oause a slight increase in the hump trim and reslstanoe but which also tends to increase the landing stability. A slmllar Increase in depth of step of the full-size alrphng was accomplished by an after movement of the step. 100.3 times the distame the position of the oenter of gravity for tab-off must be shifted. 62. In preliminary design. Hl@ negative pressures occur on the afterbody just aft cf a shallow step during landlng and high-angle porpolsing (reference 78). the step should be moved approximately 1. {9. 71. Beoause of tb angls between the forebody and the afterbody. The aerodynamic drag of the hull is increased 10 to 15 percent by the presence of the step (references 18. A vertical displacement of either the forebody or the afterbody planing surfaoe is then required in order to maintain adequate depth of step. and 10~). and 100).An Increase in depth of step raises the lower triv. w28 looation of’the step or of the wing may have to be ohanged. A forward movement of t??estep therefore is likely to be more oostly and dif’flcultthan an after movement of ths step. oal.3)and the drag . 23. Depth and Form of Main Step Depth of ste~. snd satisfactory latilng oharacteristios were obtained for both airplanes (reference 71). and 22). and reduces the violence of upper-litit p~rpolsing (references 21. Lmding instabilities of models of two airplanes were investigated in the Lang19y tanks and in both instances inoreases In depth of step resulted In aatisfaotory landlng oharacterlstics. raises the upper trim limits. . 1 (reference 14) lndlcated that when a falri. buted to the presence of a step. ~G28 . Exceptionally stable landlngs of a model have been obtained with the depth of step reduced to zero (reference 13).7. and 2. )+9. When a shallow step is used. extending back five times the depth of step.llty(referenca 10). ~ 100. Ventilation apparently has no effect on directional stabi. 25 of’a transverse step Is approximately proportional to the ar9a”of the rise of the step (re~erence-43-)-.43)and on full-size airplanes t (reference 21 Ventilation does not affect the lower trim limit of s~ability but raises the upper trim limits slightly (references 47. saved only one-sixth of the step drag. Step falrings. ~. ventilation is also effective in reducing a resistance pea?{that occurs just before hump speed (reference 27).l’?ACA ACR NO. 78.M the absence of adequate depth of step for landing stability. 78.. Fairings leaving half the depth of step were less eft’ectlvs while concave falrings.. The h rod~smic stability In talmoff and lanz Ing Is in gener2 affected adversely by the addition of a fairlng to a conventional hull although the characteristics of the Sunderland In this respect appear to be satisfactory (references 4. fairings have been used aft of the step. and 35).lh an effort to reduce the aerodynamic drag attri.near the keel as ossible has been successful on models (references 4. the use of ventilation ducts just aft of the step and as. and 100). 71. Ventilation of the step. Tests of a powered model In Langley tank no. The most notable”use of step fai.sablein order to obtain satisfactory stability.ng1s added to a conventional transverse step the use of ventilation is advl. . Tests reported In references 57 and 58 showed slmllar reductions in air drag by use of step fairings. More recent tests (unpublished) of a model with a fafred V-shape step indicated that satlstactory stability may be obtained without ventilation and that further investigation of the effects of plan fom of the step and camber of the f’nirlng would be desirable. which has a step that is V-shape in lan form.rings Has been on the Short Sunderland flying boat. The addition of a step falrlng to one of the Short Brothers flying boats (reference 260) increased the top speed by approximately 5 miles per hem. 18. Results of tests in reference 18 indicated that the step drag was practically eliminated by a falrlng extending back six times the depth of the step. . - Plan form= of step (0. several presentday flying boats a~e directlonal~y unstab16 at low taxying speeds. The lower trim lirlt is not reatly affected by changes In plan form of the step ?reference 100) but in all probability the upper limits will be shtfted in the dire~tion expe~ted fr6rnthe ahange in tk depth of step. The directional control available by throttling engines on one side lowers the reserve thrust and Inoreases the time of operating in the yawing region.reference 77 indicate that. Unstable yawing moments are Increased by the flow of water over the sides of the afterbody afi ttil extension. Tests described in. 15@8 . Other plan forms of step. The effeot of # L l-L / Forebody \ q-7 + ‘1” i“ v . change in the plan form of tlhestep on the l~lng ‘ 8tablllty cannot be Isolated beoause the landing atabtlity is so closely ass=iated with the depth of step.A transverse step is the simplest been used on most flying boats and seaplanes. however. the landing stability of a model with a transverse step and with a 30° V-step are comparable. have been used on full-stze airplanes or tested on models.26 NACA ACR No. Some of these forms are shown In figure 9. or swallow tail). with the same depth of step at the keel.. Side Steps ati Skegs When operating at overloads. I . -4 I L’ e 1 L I Swallow tail Notohed angle of V Figure 9. steps. One means of reduolng the dlreotion. NACA ACR NO. As the speed increased. The flow of water over the tail extension may Increase the violence of upper-limit uorpo?. L5G28 27 . flying The addition of a planing surfaoe or spray strips on the tail e~tension may be necessary to prevent exoesslve wetting of t% horizontal tail surface or tail turret (references 7/+ and 79).velyby multiple side steps than by a single side step (unpublished data).al Instability by “ breaking the undesirable flow is by use of vertioal steps on the sides of the afterbody. the effectiveness of ths ske s deoreased as they oame out of the water (referenod 71). Seve ra1 E arrangements of skegs on the full-size airplane were tried. TW . a negative-dihedral hydrofoil on the tail extension. the additional problems introduced by the flow of water over the tail extension ati the neoessity for spray clearance oompllcate the design. Although the flow of water over the tail extension may oontrlbut~ to th directional instability at low speed. Such steps reduoed unstable yawing moments on a model and were suooessfully used on the full-size aimlane (reference 82). and . the removal of the tail extension does not ellm. It should be emphasized that skegs. and the results”obtained were similar to those observed for the model. The addition of skegs to the afterbody and tail extension reduced uiistableyawing moments. Tail Extension Although the function of the tall extension of a bat iS similar to that of the tail extension of a comparable landplane... and ray contribute to directional insta-bllity. &i inorease in vertical clearanoe of the tail extension. may introduce landing instability at high trlrs. directional Instability of a model was reduced more effeotl.lnate hydrodyzmnio directional instability (references 23 and 56).sing.. and spoilers may substantially reduoe the unstable hydrodynamic moments but may not be completely effeotive in:stabilizlng an airplane In which rotation of the slipstream contributes an additional yawing moment.. may inorease the hump trim ti resistance. The planing action of the tall extension may decrease the hump trim and resistance bg developing dynamLc 11ft (references 39 and 79). —. —. The average length-beam ratio ourrently used for twin floats appears to be scmewhat greater than that for single floats. .=.27 for hulls (from tabulations in reference 57). 139.Adhersnce to the requirements for longitudl nal stat Yo stability usually results in length-beam r8tlos for floats that are larger than those customarily used for flylng-boat hulls averaging about 7. lhzchof the pmoedlng ~scussion relative to hulls 1s also applicable to seaplane floats. Over-all proportions and shape. A planing surface on the tail extension of a model oaused nQ reduotlon in unstable yawing moments and inoreased the range of speeds over which they occurred (referenoe 74).The effects of changes in dead rise are gener~y~same for both hulls and floats. and 30°..28 NAOA ACR HO. Lines of representatlvp floats are included in references 123. 25°. The shape of the bow of a float should be generally similar to that of the hull. . the planing areas of hulls and floats are generally similar. In the design of. and the absence of a tail extension.. 40.-MM. —mm . . - - . tie relatively greater dlstanoe from the center of gravity to the keel. In American praotloe the average dead rise for floats appears to be higher than the dead rise for hulls (referenoe 57). In particular.35 for float seaplanes as ooxnpared with 5. together with data regardin~ the aerodynamic and hydrodynamic characteristics of a wide range cf changes in shape of th bow.... Dead rise..—-.- u ‘..@ for floats h~vin~ an~les of dead rise of 20°. . . The discussions of the geometrio parameters of hulls relating primarily to stable planing motions will therefore not be repeated in the sections on floats. L5G28 an inverted-V cross section cm the tall extension were tested on a model and found to be only partially effeotive In oounteraotlng yawing tendencies (unpublished data).floats special:considerations arise from the lower reserve buoyancy. Aerodynamic and hydrodynamic data are presented in referenoe I. and 1Q3.. For twin-float designs an additional consideration Is that the dlstanoe between the floats must be ohosen to insure transverse static stability. but the low height-beam ratio restricts t~ possibls variations in the shape of the bow of a float. . 5 (reference 256) that it was found qeeessary t~ qa~ one flcat larger than the otkr for aatisfaetory qpr~ obaraoteristios..the seaplane in cubic -feet.th> total d. L5G28 . ..\ —- . a const&t normally.’ langth. Single-float seaplanes have .1. ..: .It has been tbm practlqe In float design -.n-float seaplanes specify that the longitudtnq~ metaoentrlo height . . for sta$ig longltudlnal stabil~ty indioats that.: . fG9t . -.40 Thk Canadian requirements (referenoem12C) fop imd..fio~ o$:qgw to be used. where n B. r.. ..- IVAOAACR No. “onaor two) . The high engine torque inherent -$m-qaetng seaplanes created such an eccentricity of loadlng’in.-.Aooordlng to referenoe 154.. I . “ .thq ~enQh~beem ratios of twin-float arrangements will be larger than those of pi~lo-f’l~t arrangements..requi~rnents. . ~ GM = ~ A “’.1 “beamfif’ aach float. to-fi~olumg.. . shall not bo last than 6* : . K2 2.rof flo~ts (that. . . .khe ‘ease. po&ds . .D Ip. .“.s determined from otbr conside~atlons. . .. As the “reserv... .. the .i.ll ‘ . .. A . “ . . . . .ofthe s.“:.. &e length of float: m~st”b~ suf~lclent to assure statio longitudinal stability. . f~et “ .q. nuTbe.lsplaoamentof.’ .1s”.q buoyanoy. . .. .10 . gross wsi~ht -of seaplane.. of the floats so that the buoyanoy is -—-’--some Predetezmfned percentage of the gross’ ‘lo”ad’~ va&ying —*etween 180 and 200 neroent (references 120 and 121)0 In any ease there sh~uld be enmgh exoess buoyanoy to prevent. . L. “ .. .~e. with an average value of 2. . A largq”e%c~so buoyanoy allows a lower ad more stresmline ... “ over-.giveh “w”ith sufficient accuraoy by the empirical equatton : “ . .’. . the longitudinalm~~aosntric height GM for either single or twin fluat~ is.K2nBfi “ . 29 Statlos.b~-fram submerging at low-taxying speeds.90 &d ..varying ‘between1.. where .. . Tests of four f.. fref:rence 57). .s..out.mlnimyn dr~ a-o.loadhg of 5.. twoidifference.twtn-f’l (refarence 256) show Inoreasea in resi8.yll-sizefloats in the Langley propeller=researoh tunnel (re~erenoe 127) indicated that a radical chqnge in. The. .arenoteworthy in oomparing ~hs actabilitybh~bacteristica: the pitohlng . showed small differences in reslstanoe t. :... . The seaplane had.Z!pounds per square foot.”(77percent excess buoyanoy).. kdbl to’keel.analyzed. “ 30 NACA ACR No.9 pounds per horsepower arida wing loadlng”of 27. The flow of-air over the floats was shown to be so turbulent that mincfirefinements such as flush rivets and recessed fittings would not appreciably i reduoe the drag. A1r drig of floats.Porpoising fid sktppin~ have appeared to be of much less practical signiflc~o.:anEl.s.with a blunt s~e”rnreduced “the drag 8 percbnt..ity bg-float”se”aplanes. Unpublished data from”LanE19y tests for”spacings ra~ing from 2 to 5 beam len&hs. . Effeot of spacing between floats. apparently caused-by heavy sp”ra”y wetting the tall plane and other parts of the structure.Rbsults’of wind-tunnel teats of seaplane”floats sh~” that ths fcrm”of the bow strongly affects the zrin!mm drag and the variatlbn of”“dragwith angle of pitch...a float. . .sdaplanes have len@h-be~ ratios varying from 7 *O ~ .. measurernent~‘ “ .‘L5Q?8 length-beam ratios varfi”ngfrom 5“to ~ titiietwin-float . Tests of R ~11-sizq flea} seaplane In the Langley full-scale”tunnel-(reference lu5) Indioated that the maximum speed would oe. “. .I . Adding a faired tail ex~ension’to.. Dynamic sta”b~i.increpeed from 307 tn 336 tiles per hour by removing the rnalfi float. within .eapltissth~.e in ‘pperatingflpat.h~twere almost the aqcuraoy of .Tests of a model . Although differences have not been cardhlly . . . 16 percent. -between the types .e of sfterbody keel affects the angle of minimum drag””andIs of praotical significance in the ohoioe of a conflg-~atlcm for which the mlnlmum drag till ooour within the desired range of flying speeds (referenoe 159).. in opbrattig flying boa~s. Reducing the depth of step td iero”decreased the .a ppwer.a&c~e%t ~loat apaclng up to 20 per“oent.the design of the floats “was required to obt~n” significant reductions in tti alr drag. The data have been obtained from tests in towing tanks in the speed range at which wing-tip floats are necessary. LATSRAL STABILIZERS . . Hydrodynamic data ~n -ti usual consideratemiY_i_th9 choice of‘~.been determined for a number of typioal designs of wing-tip floats. t~eir maximlm restoring moment is developed mt sn~ll &n#les of heel. es of lateral stabilizer. The evidence seems to be in favor af winG-tip floats for l.!! NACA AcR NO. in recent designs.hg. Inboard floats usually have a shallow draft at rest whereas wing-tip fleets are ~cnerally looated to clear the water at hink speed erfi. however. Inboard floats are located inbrard of about one-third the semlspan of the wing and therefore rust be larger than wing-tip floats in order to develop the same righting moment. and reoent praotioe has been to provide relatively deeper steps on floats than on hulls. only one wifig-t!pfloat contacts the water at rest.becnuse nf their location. The contour of the bottom of a tip float Is generally made to resemble that o~ a V-bottom hull am the required volume Is then disposed In a manner either to obtain minimum aerodynamic drag or to comply with other requirements (for example.. . L5G28 - 31 s ---. and they are not Influenced by t.. retraction) of the speciflo installation.gsof low aspect ratio.a%p fleet has been that any lines suitable for a main float are adapta. Some of these data are . Neither Inboard floats norstub wings have been used.Three types of lateral stabike beenusedtn the past: inboard floats. and wing-tip floats.t’low of water produced by other parts of the seaplane. Another consideration Is that for military @ a number of tkm”dlffqrent types of float se~plane have had considerably lower power loadings than the patrol and cargo types of flying boat.lter~lstnbllizers because they are relatively small. Stub wings (referen~e 156) extend outward from the chine near the main step in the fom of’aerodynamic wir.olefor a tip float (reference lk7). stub wings. radius ii gyration of’a float-saaplan9 is generally c larger than that of a comparable flying boat. The perfommnoe eharaoteristics during o~ratlon at low speed have. Tests of a liriited.ut a step (reference 164). 153. and 164. Wingtip floats have been “milt with steps to incorporate a satisfactory planing surface on a form that will have low air drag in flight.32 FTACAACR NO. . it may heel sufficiently to submerge a wing tip. C. fl~”.nificantly affecting the magnitude of the hump resistance. reduce markedly the region of speeds and trims in which low-a:n~le porpoising occurs. Captain F. for a ciistance of about 200 miles in the Atlantic Ocean (reference 211) led to the conclusion that satisfactory seaworthl.e chines to avoid losing lift at large drafts and thereby to prevent “digging in” of the float.ng of emphasis upon the iv. Later tests.portance c~fdesigning the lines above tb.. Hydrodynamic characteristics of stub wings. L5G28 reported in references 7)4. Uncle subject to the influence of tk how wave that leaves it free of “solid” water through a small range of speeds.152. His experience in l!~ailing boat. the stub wing is the hull is lightly loaded. reduce the trim at zero applied moment (reference 146). and adversely affect the upper trim limit of stability (reference 163) . hence.Airdra. 16o.ng landing. At rest. the righting moment may be insufficient when rwa-y.ness requires the tip float to be free of any tendency to ‘[digin” when making sternway. Specific test data are not available for tip floats moving astern but it has aopeared that a float with a step is advantageous because the “afterbodytr may be sloped upward to develop lift. . Data regarding the effects of variations in the position of stub wings are given in references l~L6. number of configurations indicate that stub wings redfi~ce the hump speed without si~. have shown that low air drag and satisfactory performance at low speed can also be realized withc. Richardson has emphasized in letters to the NACA that the behavior of a tip float in drifting astern is of special importance in the event of a fcjrced “ a disabled. A significant result of the tests has been the placj. and 151. the dynanic stab!lity. stub wings develop their maximum righting moment at very large angles of heel.g. and the trailsverse static stability of the flying boat.. l~?.Interference between the water flow around the hull and the stubs affects the resistance tine trimming moment. the NC-3.ats that have wing-tip floats cl~rrently considered . however. If the flying boat with stub wings is not accelerated rapidly through this speed range.The air drag of tip floats amounts to 3: to 8 percent of the total drag for a nuhber of flying b. Present status of design criterions.. T& air drag of partially retracted tip floats may be estimated from data concerning protuberances on the lower surface of the wing (references 157 and 158). 118 3=Q---’12 ~-’” of air drag of hull and Figure 10. taken as 100 (from reference 18).) Results of tests ‘~-. basic hull. L5G28 33 well streamlined.1 [. The spec~ficatioris present formulas for computin~ the size of conventional lateral stabilizers for obtaining an arbitrary minimum lateral stability at rest. Current American practice conforms in eneral to the specifications given in references 6 and 1f 7.s Numbers :~i.a~ram. 59.ve drag relation to lateral stabilizers.. 10. (See fig.Several different specifications and criterions have been used in the past-for lateral stabilizers (references 51. \/ .Comparative dl.NACA ACR NO. Reference 18 contains a comparison of the air drag of six configurations of flying-boat hulls differing only in the arrangement of the lateral stabilizers. the aiu flow In cruising flight to avoid excessive air drag.. -132 5. Reference 1$0 presents data showing the air drag of wing-tip floats to be of the same order of magnitude as the air drag of well-faired unretracted landing gear on comparable landplanes. of four different types of conventional wing-tip float (reference 153 ) led to the sigylificant conclusion that the chines of an unretracted wins-tip float should be alined with. and 251). Current practice is to provide the righting moments needed to . gerat high speed..n row~h water. Raaid retracttcm and e~tenslon would pezmlt the wing-tip fl~ats to be Iocatad out of d~~. . lll~conventlonal forms of st~bilizqrs.uat~on cann”~tbe designed with assurance that the hig~. unsymretrioal slipstream.~tha h~raf~i. A comparison of tha drag of the straamllne sFape with that . and wave slope are lfsted in c-utlininga procad. For the larger sizes of’flying boat the reserve bu~yanoy is very much larger than ejther of the other two allowances (reference 162) and a more detailed exaninatlon of the desib.A larGe reduction ~n~rag ol?a ixe~fia~r-e realtzed by using a streamline sp?.34 NACA ACR No.1 instead of a conventicmal sh~ne.>nf. Unpublisl-ed oate that. tlfis shape would give rise to ver~ large dyna~lc lift that would necessitate a type of oleo ~trut far operation I.GEnd test results ars presented in rofereilces159 and 161.is by usa of the dynamic and buoyant .anheretofore employed 1s considered necessary If the structural and aerodynamic efflcleno~ are not to be unduly Inpalred by ths tip floats. Yntll..tsmay be adequate.requirements tl. shallow floats haviw th9 form of a somewhat distorted s. if the tip floats can be dssfgned to have sultablo d~amic reaction when . the numerous upsetting moments inoluding propeller torque.-spsadctxmsoteristics will be satis~”aotory.’fa conventional wing-tip float is rade in re:erer.adsquata data are available for ~redictinz the h~dr~d~nan!c lift and drag cf hydrofoils.qharicalse~ment hava been suggested data frm tank tests lndl(reference 150). A very flnterestir~possibility for ootalnln& lateral stablltzation.ca14.p.~ne~ut test results do not appear to be nvailabl. L5Q28 omnteraot the upsettln~ moments due to gravity and oross wjnd and to provide an additional reserve buoyancy determi~ed on the basis of past experience. although retraction would ~~efacilitated.waller tip flaats than these currently wed ml large fiyirg boe.wbmerged.ndlefitted ~..5. A streamline float of rectangular cross sectinn witl. t?IIstype’-ofc. Th9r9 ?s sore Indioatlon that.q. Stabilizers at tkls klnt are shown in reference lc. Broad.a hydrofoil was used on the ND-1 float snanl.urefor defining !n detail the necessary buoyamt and dynamic characteristics or tip flo6ts. In reference 155. especially for htgh=pgrformance singleen:lne seaplanes. sistance b critioal. #AERODYNAMIC AND FR3PUi&VE CONSIDERATIONS The aerodynaml~ and propulsive arrangements for flying boats are prlmcmily determined by their flight perforranoe specifications.Current practioe shows that If the propellers have adequate clearanoe WQ. TIE angle of incidence of the wind is of significance in relat!sn to the hump trim and tke trim of the hull In flight.S and flaps are adequatel~clear. “ . .The araa of the wing is deteminsd by the service conditions for which the flying beet Is desi~ned.hoasgsct rotio (refersnce 167).putationsshow that take-off performance is improved by inor~asing t.o oonslderetlons that may modify these confi~uratlons sre d$scussed in this section.’1 . Vinq. canvas bags filled wlth”wator and kung in t. 35 properties df the tiihg’”lockted 1% *e-iOw=wing pOiltionD as described in the sec~ton entitled ~Unoonventional Configurations. (See section entitled ‘lPropellers._ ?’ NACA ACR NO.. The main effect of hj~h wtng loadings on tie take-off performance of 9 flytn~ boat appears In the higher getaway speeds.-emergency stabilizing devices can be provided in the form of sea anchors (trltumf~ buckets. When the high-speed rc. Although flap deflection increases the .the resistance at h’. As the pet-away spesd becomes hi~~her. Hydrodynad. L5G28 . Cow. . ---- -— — —.When Zt is necessary for a seaplane to remain at rest under abnomually severe conditions. Emer. —.. .-.u) . as shown In reference 32) or #Inflatable devloes.. “ tlm setting that gives best take-o”ffcharaaterlstics may be taken as approximately that which gives minimum total reaistanoe at 65 nercent of the stalling speed (referemes w and 167).% water fror an outboard position on the wing. The general practice in airpl&ne design is to mount the engine naoellas on the wing with ths thrast line approximating the chord of the wln&.zenoydevloes._.l%m effect & flaps on the take-off Is pronounced on airqlanes h~ving high wing and power loadlngs.ghs~eeds becomes ~-ores@if’icant. which are beyond the scope of this report. . in fact. At low speeds. At Mgher speeds. . the spray is higher Et the tips of the tail than at the roct so tkat the use of considerable dihedral angle may be advantageous. Tail eurfaoes. . thts dihedral angle may be oarried to the extreme nf employing a V-tail (referenoe 169). . tha effact of increasing tail area . . The lift on the wing~ Qt a flying boat moored on the water may be reduoed b~ j?lap-t~pespoilers mounted on the upper surface of the wing between 5 ati 20 peroent of the chord with no san between them and the wi~ surface (reference 1~1).. The aerod~amic stabilit~ ~erlvatlves have some effect on hydrodynamic stabllit (references 46 and 106).. ~1. At a given high sneed. . . Ths bow-dawn moment requires up-elevator defleotlons to counteract it end shifts the stable range of cente~~f-gravity pos?.. .= The horizontal tall is usually mouted rather htgh to clear tk spray.g them part way for takeoff (reference 170)? Dsf’ledtlngthe flaps reduoes the load on the water an’1causes a bow-down moment (referenoe 47). 15G28 total resistawes lb genaprnllyimproves the take-off performance by loweting the stalling speed. By raduotlon of tln load on the water the trim limits are generally lowered slightly.— . . .. The optimum take-off oan be made by taxying to high speed with the flaps up and def’laotln.:6that for th oases considered ther~in It was quite Impossible to neglect ‘the aerodynamic faotors although the hydrodynamic effects appeared to be ruch mare important than tk aerodynamic factors.36 NACA ACR No. It is pointed out in reference T . particularly at high speeds.ttonsaft (reference 166). .s device should be useful if an airplane having a law wing loading is to be moored In a b.ighwind. .. the roaoh may wet the tail heavily. The control system presents a complicated design problem. . Variations from the usual sfze of the horizontal tail have a small effect on the lower trim limit of stability Reference 22 shows that increasing the damping in pitoh due to the horizontal tai1 ~ decreases the lower limit of stability. Approximately the same total area is required but there is a possibility of reduoing the air drag by eliminating one intersection with the fuselage.. The decrease is small at low speeds and 1s appreciable at high speeds. CJnsome heavll~ lnaded flyin~ heats.ng propellers (reference 72) . Pro ellers. The effeot of the slipstream and thrust is to ohan&e the load on water and the trinmlng moment and to Influenoe . SoU@ spray profiles for unpowered models are given in ~feronces 20 and 25)~.. both the lntgnsit~ of the spray end ihe width of the speed range when the ~Pre. During take-off.glble effect on the upper branoh of the upper trim llmlt of atabllity..rj. Propellers tlnnlng inboard at the top provide slightly better rudder control than those turning outboard. Unpublished data fndlo~te that a model of a flying boat with a gross-load ooeffielent of 1. The ri~ht-hand rotation of nropellsrs tends to make the flylng boat yaw to the left. L5G28 57 . the hull is directionally unstable just below the hump.6 requlnd a yawing-moment coefficient Cn of 0.NACA ACR No.. The yawing moment coefficient whore w is speciflo weight cf water and b Is the beam. No data have been published on the amount of yawing moment required of the vertioal tall (or of water rudders) to maintain oontrol throughout the taxi and take-off run.not veq. A heavily loaded flylng boat with right-hati propellers often makes uncontrollable tuzms to tke left at this speed..12 to maintain a straight omrse. With opposite rotation of the propellers.05 at a speed ooefflolent of 2.sl~lf~~nn-$at the normal values of tail damping. the yawing oharacteristlos are symmet. These trends ark””al%oIYidioatedln-referenoes 53 ati 106. !l’lne inflow of sl. For any ~ti verlconvent~rnal flytng boat.rto powered propellers picks up spray that wauld ~lothit ttiewindmllll.y18 in the Pr~Pelle~’~~ncrea~e with ~ncreaslllg ~??oss laad (referen>e 61). spray+!%37 e farebody enters the propellers during a short range of speeds just prior to hump sveed. The tall dmupt~ has a negli.cal about zero yaw. . becomes less marke~ M m ta~l damping Inoreases ad Is. . Reference 7~ shows that the effect of power on trim llmits and center-of-gravity limits of a model Is large. An advantage of this type of jet Is Iihatit may be turned on and off as desired. . UNCWVE?TTONAL COYFIGCPATIOllS Tunnel bottors.. the center of gravity of the airplane so that wken the thrust ceases no great change in the balance of ths airplane will result. The jet engines for use on high-speed airplanes wauld probalily have sufficient thrust for take-~ff. I 38 NACA ACR No. Jet engines designed to produce a given thrust at flight sneeds may be at a disadvantage during take-off when compared with normal propellers because of differences in the ra?!nerin which thrust vazies with speed. The assisting jets are either of the powder type. ~G28 the water flow around the. provided a suitable location for the air Inlet can be found. to take off In a shorter distance. Jet propulsion. The location of th assisting jets Is not particularly critical.—-. They should be so arranged that the line of thrust passes througlh. There is no Information as to the extent that the inflaw of air wI1l pick up spray or to the extmt that spray will damage the inteti-orof the jet motors if It is allowed to enter with the air.on. “ One liquid-type jet has operated successfully under water (reference 165) but no information is available as to the behav!or of the powder-type jet wlwn submerged.hull. or of the type in which liqtids are forced Into a combustion chamber. Decreaalng the power loading of a flying boat Increases the acceleration during take-off but reference 50 shows that there is a relatively small change in the stable center-of-gravity range with change in acceler~ti. The liquid-type :et generally onerates for lower periods of tin% but requires that more equipment be carried In the airplane throughout the flight. which may be dropped after take-off. Jst engines could be mounted claser to the water than engin6-driven prop~llers. or to talk off with loads greater than those possible with normal engine power.or slightly below..Jet assistance has enabled flying boats to take off more quickly in rough water.FTullforms with a tunnel bottom (an inverted V ) ‘navebeen nroposed occasionally because ——. the afterbody may be wet excessively unless large clearanoe la provided.and 177).oriy~~ with conventional floats with regard to porpoislng. If the spray Is oonflned to the tunnel. It was found that these floats were olean running and compared satlsfact.The spray between tha floats of a *float sTF~ngins seaplane resulting from the meeting of the tw~ how blisters sometimes enters the propell~r In excessive amounts.. however. Flpme 11.g.Asymmetrlcal float ior twin-float seaplane.A form of hull that Inherently has e c araoteri. water resistance.oalfloats. 17’2. 11]. atri. L5G28 39 the arrountof spray thrown out laterally is exoeptlonally small (referencafi 3. This unusual form had very good spray oharaoterlstics and would presumably have acceptable resistance and stability oharaoteristlcs. some ... A Fair of floats was desi~gmd (reference 12k) hating the plsn~ng bottoms arra~ad on the outer cidss ~f the fl~ats (fl. Wind-tunnel tests and structural studies showed.sties is being developed by %%3s%! . and directional atabillty. Kodifioat?. A model with a forebody hating &UIinverted-v Gross 600tiOn at t~ bow with a transition to normal V-bottom about halfway along th f~rebody was tested at the Short Brothers Tank (referenoe 260). seotion at step. that the air drag and the weight would be excessive.NACA ACR NO. Conf@ratlons of the types that have been tested present a diffioult problem In avoiding excessive air drag.ons intended to reduoe the air drag of the asymmetrical floats introduced t!ircctional instability. Preliminary tests (reference 176) and flmthar tests of modiflcatims . Tests of a dynamtc .q 40 NACA ACR NO.no.. Figure 12 shows a typical configuration with a very dsep stop that Is - FJgura 12. 2. pointed in plan form combined w~th a long afterbody.Planing-tail conf’l&uratlon.5 compared with # = 5). L5G28 tests of models In Langley tank.sImllarto those in f!g~me 12 showed that the hump rasistancs was lawer than that of a conventional hull (: = 6. Figure 13. the $~erodynmric anEle of =fterbody keel.Planing flaps. r!dio&t”e”d’ that “s afiafaotody stability““oharaoterons istlos may be expeoted (unpublished data). At plsnlng speeds the flaqs would be retracted to prevent high-angle porpolsing from gcourring in the usual range of trim. IiLxitatl on the usable spaoe aft of the osnter of gratity may be undesirable for some t3pes of servloe.NACA ACR NO. effect of a big> The stwctural welpht. .. L227b4-J forebody k~el (b) Conventional af’terbody. L5G28 41 model “i.Retractable planing flaps have been for use on the afterbbdy in a manner that would ~%%wsa~ unusually high angle of afterbody keel (fig. Tank tests were made at Stevens Institute of Technology to determine several configuretims that would have suitable hydrodynarlo characteristics (reference 178).possibilities of this type of flap. 13(a)) The flap would perform the nbrmal function of the afterbody at speeds through the hump speed. and t. Reference 178 inoludes results obt~ined from tests of a hull w!th a conventional afterbad~ to which Pas added a nlanlng flap near the sternpost (fiE.h~necessity for adjusting the flap during take-off p~esent problams that introduoe some doubt as to the practic~l. Planing flaps. The results of the tests showing that (a) Fiighafterbody. 13(b)).. Float-win desi-ns. L> pro’n. — .. Hydrod~”arlc c~aracterlstics of the full-size glider we% reported to be satlsfaotory L.- .W...rt:% trail..1 42 NACA ACR ITo. . ded th flaps were not deflected while in cantact with the water.. it appears that a high-performance seaglarlewith garaslte drag practically equal to that of an equivalent landplane could be developed. A preli~icary desjgn of a float-wing seaplena that would ernloy a pusher pro-leller in a transverse p?-anenes.ade. If a SUJtek. 1.. ..gle porpolsing was suppressed were not confimed in tests (unpublished data) of a’similar configuration on a powered model In Langley tank no.Tests have 139t311 made of’models and of a full-size glider having (refei%%ces –-&=+75! a conventional hull combined with a wing placed sufficiently lcw to pr~vifiesuitable transverse s*abllity on the water (fig.inged. 14)..—. { + ‘—- Lav.g9of the wing is kmowr!to Lave been r... . — —..L.—.lestructure were provided inr the power unit and for those pwtions of’ the wing and flaps subjected to water loads.L5G28 Mgh-a. . — .. —-. Prellmiinary results of tank tests and of structural studies are C5ted to support tkm belief that largo seaplanes can be built in one of tlteprop~sed forms with considerable reduotion in weight end in paraslte drag compared with oonventlonel flying boats ad landplenes. Althau~ hydrofoils have been successfully employed on n. 189.. ---- --._ Hydrofoils having cambered sections selected to delay. oes on wing-tip floats has long been m interesting possibility with rsference to the reduction of air draq ati the simplification of structural problems.-. . Two cf the proposed configurations are shown In”figure 15.-- .meroussea lanes with a relativel$ Imf stalling speed (refemnoe 18 6).ation regarctlngthe influen~a of cavitaticm.. -. ng hulls offer some possibility of reducing the structural wei~t and t% haztirdsasso~lated with ‘!mpactsin rough vatsr. . an evaluation of’their potential use on sea~lanes that rust. and 201) (3) Cavitation caused vibration that became more severe with increased speed —-— .. 1 at depths up to ~ chord lengths and at speeds up to 60 wiles per hour. 43 “ H-Ul~=l&SE’’&e”S3 #ris. lncluding n flying wing.operete on the water at speeds above 60 miles per %nur IS hi~dered by ~r.adequate~nfo~. NAC~ ACR NO. .._. It has appeered that hydrofofl 1s when compared with plan~.cavitation as much as appeared practic~ble were towed--in l%~ley=tunk no. L5G28 .“In“re-fe-rence 173 several designs are proposed.- . A8 the speed was increased from h to 60 wiles per hour. in ~’!ch the hydrodynamlo and flotation requirements would be tncorporated as primary components of the wing. HYDROFC1L9 The application of hyd~ofoils to serve as a type of landing gear on seaplanes or as auxiliary ltftlng devl. the results showed that: (1) The angle of zero lift inoreased about 3° (2) The maximum lift-drag ratio decreased steadily from about 16 at 40 miles per hour to 8 at ~ wiles per hour (references 161. . — m“”” A/ NACA ACR No.Hull-less design from reference 173. .—-—+1. 15G28 F+ -- Floats for longitudinal static stability are relawoted to fom wing tips Fi~re 15. .onfor a seaplsr:e may be oarrled out .of planoconvex circular-qro sectlons In which extensive oavltqtion -~as obtained (referenoe 200 )..ng near ‘&e water surface kI’.ig flow Wf11 have more favorable llftdrag rat~os--ifthe lower surface IS flat rather then oonvex.testsd at low speeds by T1.~ale cavitation is represented are ticms in WY:?CI1 ? required.plane oonfip. The theo‘iwtib-alresults In reference 183 are in partial agreement with the tr~nds given ‘butthere Is still considerable doubt as to the magnitude of ths Influenoe or .eto avoid much of the danger associated with porpoislng. before-a-practiotil”deslgn of a mono. . with full assuranae that stuuility and efficient lift1.- . .V . ~d 192). Monoplane fi]drofoilsare likely to suffer abrupt and largo oha~os in lift and dreg when clnse to the frse water surface {refensnces 180. Tha raqulred technique for operation in smooth water oan be si. . L5G28 ..wate~~el.. 184.esame tlm. ~“ La~~erltke arrangements of hydrofoils with dihedral of about 20° that have been used on seaplanes and on surfaoe ~cats apparently offer sati. 131.gation !. Furt%r ~nvsstfl.sfaotory stability. and skipping.. yawing. but tho associated struts and Interference effeots are si~~ifioant saurcas of drag and spray (references 180. but for operation in rough water the importance Of pO~OiSi~# yawtn~. 185.. and lqo). The ssveritv of this typ~ of ~nstabllitT is 193s for Hlw klch~r an~les of dihedral because of the mar-]gradual rs~flng action as the hydrofoil passss into or cut of the water. PIL@TII?GAND HAJ:DLING A few clearly established principles oan be outlined that wI1l assist the pilot of e seaplane of convmtional design to take off in the least ttme and distance possible and at t~. hcwover.oavltatlong There is some indication that a I@rofoll-”in %kfizt-~t.’m besn pr~~osed a~d.~icultyClf:Iperatl.mdercondi‘ ‘lull-s. 45 I \ s~~~a&” t~g”fid~’ wer”zm-obtained ln . NACA ACR HO.matl. ..~plystated. Tast~ in a w~ter tunnel (reference 19~) indicated that slots in a h~drofail were ineffective in preventing oavltatlon. 1’ drag ratios wi11 be achieved (ref’elwnce1~$).et:evs(refererlos 1~~) and by Grunberg (references lij5and 1 1).. ad skipping as oompared with the Importance of the waves to be encountered .tests . S:~sterrs of rmnnnlarws designed to ove--cme thin dif. . The usual instructions to apply up elevators whenever porpolsing occurs (references 205. L5Q28 in any particular instance must be evaluated on the basis of the personal observation and experience of the pilot. No satisfactory technique or instrumentation appears to be available that will enable the pilot to judge with confidence the point of contacting t~ water surfaoe. and 211) are applicable only to the low-angle type. A disastrous type of yawing may occur at speeds near get-away if th hull is allowed to trim too low (referenoe 40)..Instructions to pilots regarding porpoising shoul~ clearly distinguish between the lowangle type and the high-angle type. Take-offs from glassy water have frequently been renorted to be more dlfflcult than those from choppy water. Differences of oplnton regarding these observations are sufficientl~ great to justify a brief series of tank tests or flight tests in which the influence of wind (which generally accompanies rough water) and the influence of trim may be isolated from the effects of small waves on the resistance during take-off. Uncontrollable yawing of some flying boats may occur The yawing at speeds In either of two speed ra~es. 206. Recovery from the high-angle type of porpoising calls for down elevators. Possibly absolute altimeters will com into sufficiently wide use to justify their development to a stage at which they can be used for glassy-water landings. Terrain olearmce indicators tight be of considerable value if they could be made to indicate accurately at very low altitudes. Stabilitr. approaching the hump is associated with an unstable type of flow over the bottom arxisides of the afterbody and may be aggravated by unsymmetrical slipstream over ths tall. The principles for oaeration in smooth water have been sufficiently well established by tests of models and full-size aircraft to justify a revision of some of the practices that appear to be currently accepted. y of accurately observing height out t%%%%%”‘eferences 205’206’ ‘dthe 211 ?“’nt above the surface of the water as a seaplane approaches a landing on glassy water.~6 NAOA ACR No. Definite data regarding these observations are not sufficient to justify very definite conclusions. especially if there is a lowhanging mist. Coast Guard to investigate ~. -/. In several Instances the use of jets at dangerous momnts was believed to have saved the airplane from severe damage.g down tlm slope of a w~vu were nfitsubstUnt5. For winds of less than 20 knots the most favorable direction was found to be parallel to the crests of the swells.water” and to evaluate ‘thehazards that are Znvolved T reference 203. If the wind is greaier than 20 knots. .)b It Is understood that wave heights ranged f’rum8 or 10 inches up to about 15 feet during the course of the tests.-7 ----..e merits of different piloting teohnlques in ro . but the results provide a noteworthy basis for setting up general principles for piloting tn rouglhwater. .. Jets of the sollc%fuel type were used in of the take-offs and found to be a very uaeAfuladjunot In roughwater operation. Two of the four propellers are therefore continuously in reverse and the maneuvering In any desired direction is accomplished by manipulation of the throttles. Drift in a cro~s-wind landing was found to be of little practical consequence..e%c&een greatly facilitated by the use of rewrstble propellers that permit braking and maneuvering in close quarters. Yiitha complicated sea. the recommended direction for the run is into the wind. . .~if —. Reference 209 describes the maneuverability of a PB2Y-3 with reverslblepltch propeller and states that those propellers reverse In from 10 to 15 seconds. S. Rou@ water.ated.A PElil-3C flylng boat has recently been %ested by he U..Maneumring to a buoy or other rnoorlng. Down-swell.landlngs were considered feasible but more severe than along-swgll landings. . . so~Le Reversible ro ellers. which Is considered slower than desirable. -. 15c128 47 . Previously held fears of danger ~rom drag~lng a wing-tip float in a swell on the beam or ~roinSldealippti. .—— NAOA ACR No. the pilot should choose a Cirection for landing or take-off that will avoid heading directly into any wave system and w1ll at the same time kfiepthe wind as nearly ahead as possible. Results of’the tests indicated that before making a landing in the open sea the pilot should fly at different altitudes to obserm the different wave systems that may be prssent and Zn general tc select the direction of run and the area that will result in the least number of severe wave impacts. The tests were llmited to the one airplane and to the sea conditions prevailing off the coast of southern California.. --— . Langley Memorial Aeronautical Laboratory National Adviscry Committee for Aeronautics Langley Field. . Va.. @ NACA ACR NO.. L5G28 Depth of water.. -.Tests of’models have indicated that ““ the water resistance is praotlcally unaffected by variations in depth for depths greater than about 1 beam length. At lesser depths the hwnp resistance may be considerably more than that for deep water (references 210 and ~). 1936. Alllscn.” Specification for the S.truotural Design of ~ “ 6.L: ~ body Keel on th~ Water Perf’ormsnce of a FlyingBoat Hull Model.: Tank !l%stsof a Model of One Hull of the Savota s-55-x Flying Boat . .. NAVAER SS-17A (superseding . NACA TN No.1936.A.A. Allison. Floats. resistance. ~.XVT. 1939. 541.A.C. ld.SS-. FIight.A.C. 1935. Model 52. Bur. and Ward.. Anon. “m 2.igenoe of the National AcIvisQry (lomnittee for Aeronautiaa. 576.N. -NACA TN No.: . 3. NACA TN No. Kenneth E. are rnarkec?i wi:than asterlsk~ In speolal uases requssts for -se repor$~ may be granted.. NACA TN No. John M. .: Tank Tesfs of Models of I’lyingBoat Hulls Having Longitudinal Steps.: .NACA ACR NO. . spray strips. B I B LI”:O.17). end Float External Bracing. John M. Resistance. resistance. 535. F’LYINGkAT IiULU . . 40 Allison. . John M. .N..: The Biggest Short. XX.N. 574. Allison.Model 46. either for security.. 1938.4. Discussion with numerous illustrations of the structural design and ‘arra~ement of the Short ‘Golden Hind. groprietary~ or other reasons.Angle of titer1. vol. 7. NACA TN No. .A.. Anon... “ -.The Effect of t. . Model 11-C.194. Angle of afterbody keel.should. be.A. Depth of step. Any such requests.no.. . . longitudinal steps. . Aero.: Hulls. “@8 . John.: The ‘Effectof Depth of Step on the Water Performance of a Flying-Boat Hull Model . “ 49 .: Tank”Tests of a Model of the Hull Of the Navy PB-1 Flylng Boat .. 635.C.159~ July 20. .Jan. Resistance. % Reports that are not generally available for distribution.direoted”to the”C)f’tloe of Aeronautical Intell. testing procedure. Joe W. 1935. Resistance. Bell. h”RA P-H”’Y .angle of dead rise. “ Longitudinal stability (trim limlta). @J+o Landings. Howard~ Effect of Length-Beam Ratio on Resistance and Spray of Thrge Models of Flying-Boat Hulls.. Joe W.and Willis. Angle of dead rise. %0.-ven “ 11. spray. longitudl.Antm: Landing Char= acteristics -of-aModel of’s Flying Boat with. location . fIlation.ty (landings). . Feb. Planlng Bottom near the Step. 3J23. resistance.naI stability (center-of-gravity limits)..A.... angle of dead rise. 12. Bensonr. -- I 50 . mid Goldenbaum. Robert F. June 14.%all Downward Projection (Hook) on the “. Charlie C. resistance.James M.A.. depth of step. J&nes M. of step. Garrison.the ‘ Depth-of Step Reduced to Zero by Means of a Retractable Planing Flap. L$. . Aero. 1939. Step fairings. resistance. spray. spray.XACA”Model 147. 1943. --- -..: . 19k5. Benson. . hook on forebody. Bell.. Tests of a l/10-Size Dynamically Similar Model o~:the Consolidated XPB3Y-1 Flying Boat In NACA Tank No.: Hydrodynamic-Stability Tests of a. Model of a Flying Boat and of a Planing Surface Having a . NACA RB. lq43.Tank Tests of a Flying-Boat Model Equipped with Several Types of I?ai’ring Designed to Reduce the Air Drag of the -“” Main Ztep.. resistance.. NACA ARR No.: Tank Tests to Determine the Effects of tb Chino Flare of a Flying-Boat Hull .. Jr. landings. 4Bc8. 725. Joe W. Longitudinal stability. yawin stability. and zeck..: The Ef”fects of Angle of Dead Rise and Angle of Afterhody Keel on the Resistance of a Model of a Flying-Boat Hull. 1 .-.m 1-1= . .C. NACA ~CR No: L5”w8 FLYING-BOAT HUIXLS 8. planinp flaps.” Length-beam ratio. Joe W.. . John M. Chine flare. Bel&tiJ~eMW. Bur. 1943. . angle of afterbody keel. NACA TN No. . Jan. depth of step. and Havens. NACA ARR No. ... Benson. Olson. . . 1943. Roland E.longitudinal stabil~. 9. Jmes M.. . and I?reinofner. “ 13. HACA MR. NACA ARR. and Olson. BS1l. angle of afterbody keel. Roland E. NACA RB No. L5C09b. BS1l.. Model Series 62 and 69.N. Davidson. . NACA Tank No. . ‘ “I@&8 ‘ . . . 2 of Three l/&Full-Size Models of . .:“ArthurW. o . &15. Ii: :E:: ‘:Sumnqry of Dynimlc! Tank T6st8 Of the l/& Sca2e-XBLY-1 titn Spray Strips.. 1. .. P. design parameters. .Experiwnt . yawing.:“. .-2iH-~-pl~. NACA m AC. Xhc. and Suarez. . .NACA ARR No. . Aug. Davidscm.. .-..A.: Some Analyses of Systematic Experiments on the Resistance and Porpolslvg Charaoteri. W.. ..”NO”. form: of aten.3. depth of step. .” and .. “. Rep.:P. General Tank Tests on tk Hydrodynamic o Charac-. effect of’be~.re~i stance . Length-besm ratio. . . .. Kenneth S. PP. z .. form. .atlow speeds. len@hbemn ratlo. IX. form. 3106. Longitudinal stability. Flylng:Boat Hulls at Low Speeds . and Locke.drfftlngasterp. take-off...: Tank Tests of a Ysmtly b~.British R..A.. 1943. 106. .1~~~~ Handling on. with Locke...E. . 194A Length-beam ratio. .-— . Anthony: Porpolsing -“A Comparison of Theory with. 21. . K.NACA . Tes.: The Air Drag of Hulls. 18. . . ~ “. depth”of hull. flwe. nsl stability.. . res~sttice. and “ Clark.315 -321.“W. Carter. trim “.. No.. . S.: 20. . arigleof dead rlse.-. . . seaworkhlnesg. Kenneth S: M.L.‘ No. . 1943.. air drag.Stub wings.. Kenneth S.— - . . F. NACAMR. 19. ... olhlne . 3ACA ARR No.. 1936.$sin Lan@ley tank no. Rep. . and Locke. J9 3. Clark.. q .: No v.t% whter. no. . teriatits.1937. ~.O . S.Je. F.(trim llmtts)... resistance.Vulteb“ Airoraf% Corp. Jr. Aircraft Engineering.2~m Air drag. 3G07. K. . . Davidson. vol. Jr. NACA ARR Nn. step falrings. method of plotting. 51.Cooml@s~L.Models 116E~3& 120R. and 1~.sties of Flying-Boat Hulls. . Longitude. ventilation. . S..Four Hulls of Varying Length to Beam Rati0. re~lstance. . . W.F~ W. . . (MPeral Fre6 to Tr’imTests in 16.9ngthBeam’Ratin. Jr. Coombes.. 1350. tip floats. longitudinal stability....n19..3.. M.cConsolidated. M.. .: W. effecfs of warping. ““m’ooiie.— . . spray.. .. FL~G-BOAT Hiliis “ %5.af Four Flying-Boat Hull Models of DMYering L. . B. “ . .1935. I. NACA .4CATN NOc 522. . yawing.S. angle of dead rise.A. . tail damping rate. . .“ .” “. . gro”ssload.Series.j Jr:: Some Syste@atlc Model Experlments on the Porpolsing ..: A General Tank Test of N. Rep No.w. few. Joh R. . .fYectof Ventilating tlm Step. .TN No. No. 538. 24. . resistance. form of step. Plan form of step.. ?hdel 11-C Flying-Boat Hull. Dawson. . . ti&le of dead rise’.Fluted bottom..: Analysis of Results . . . Johh R.D-5558.Conne~. Diehl?.. . tunnel bottom. chine flare... .ACARep.-.US3 of General Test DEia. Pointed step. ”angle of dead rise. 28. . warping.Pointed-StepType with i)iffere~tAhg~es -of Dead Rise ~ N. . 453.:”-~ Capacity of Seaplanes and Flying mats. F. ~ooke. limit). Boetng Air. DawaonX John R. forebody . C. .ted with the Design Of-Hulls of Flying Boats “and !jhe .A.. Model 35 . “W. . *23.: -TankTests of Two ~lodelsof FlyingBoat Hulis to Determine the E. Resis~an6b~ ds::i~nGaramgters. Tests in Langley ta~ no.. resist~oe. Walter S. “ “ -. 15G28 FLYING-BOAT HULLS “. . resistance. Davlss B!.. resistance. 26. sternpost angle~ depth of step.Walter. 4 27D Dawson.A. . Kenneth S. . and”.Venti’latlon. ! . .1 “ Characteristics of Flyi~=Boat “Hulls. 3936. N... 3F12m 19~3.WIth”a “Flvte.Boat Hull. 594? 1937. ~ Disuusslofiof Certain Problems . # me~hmis cd’plottings range “of test pr:j@~.S. hydrofoils.: . . 625. . l. Longitudinal stability. FIFing-Boat Hulls ox the . Including the Effect “of Changing the PlaiiForm of the Step. “~: .lengt-h-~eam ratio.: Tank Testk of Thrge Models of . m No..”Datidson-. v. Estiratlon of ‘“Maximum Load 29: Diehl.near . . step fairi~g. spray and wake measurements. DawsQn.Longitudinal stability (trim . 1935. ‘NAC~: TN No. .. NACA Rep. . 1932. NACA TN No. . . .Re.lationbetween gross load and time for take-off of seaplanes. 193~.Hydrodynami”d ‘Rese~rch Projact. .. “ 22.Co. 1944. .l. ”depth of step. craft . 23.d Bottom.C. .... Sept. . A.25.52 NACA ACR No.: Tank Tests of a Model of a ‘F1ylng. . . resistance tests. sternpost.. . 551. John R. NACA ARR NO. .&alter S. Sept. no.. Bur. chfne fl=reo .
[email protected]+2k . vol. .. . 27~... press~re measurements on hulls. full-soale reslstame. ‘DofiierD6:X. Nov.. 194.X~: . .S.— ..-British R.Lessdns of the”Do. vol.on Somd Tank Tests on the Sunderland III for Take=Off at Extreme Overload. “19739’ Pp: 757-7820 Design. 36. .” .E.. . 33ti: Dornier... .: . .. . 25. . 2.. m Impaot. hull and tip floats.s and Garrlsom. its construction and operation. G. .“ q “. 19.’ ~ . 52. .” c. no.”XXXVII. General aerodynamic design features.th’ the NAGA Events Reco~r.measurements. s .NACA IMP. 19S. yawing.. Charlie C. . .-.. . . . “.. Ott. 2. . step falrlng. 53 -FL~GyBOAT Hums .Fletcher. T. “Diehl~. step fairing.no. no. Sept. VO1. Soale effect. . Compilation of aerodynamic .. no. pp. of’.’”. no. “ ati”Llewdiyn-Davie s. 1935. A.30P.. 193 .: S?aplqne ResearpL Jour. Floats and Hulls. I.. .. pp. . . Q30-863.: “‘T6st4 on Alrpl~m l?uielages.. . Ott 1934. ... .: “Mrnier. “Seaplane..: Note. 1926. . Tests of a Navy PBM-3 Flying Boat V1. Walter”: S:. longitudinal stability.000-pound PP~ 339-3@~ flying boat. . Aug.S. . . pP. wln~ flllet~.= Tunnel. M. Aero. . NACA TN HO”.Jour. . -: :. 5L-56. — . Garner.: Basio Design Featyres of the Sikorsky S-@. seaworthiness. \643.. . R. . 2. . i .“. . ’38.. vol. .3. .voh 1. z . .3. l?qllmer. h:” 256. .R. spray. 2730 Sept.”D. . #ero-1~87.. end vol. ~?~6. .. ‘. 1934.. Franchimdnt. Rep.. Jr. 50. 32.: 3~.!J.:Claudius: The-” Alrm%ll’
[email protected] F.. .”25..:. XXXVIZ. Eydr.odynamlc. H. Dee. pp.. Aero Digest.A. P. ~trlnsn~ng “buckets. F lylng=Eoat Take-Off. 24. . . .”H. 31. ~ Jr.tes~data. 3. . M34. Discussion of tM 100. . No.: Tests of a“l/hO-Scale Wing-Hull Model snd a l/10-Soale Float-Strut Model of the Hughes-Kaiser Cargo Airplane in the Two-Dimensional Low-Turbulence P~essu. .. 37.A. Air drag. . .A. . Takb-oofrcalculations. . 1929. . 10.A Sttid~” . L. Ebert} -JohnW. NACA ~. “ NACA MR.. stub wings.D@hl. . ir.Flying-Bdats and TMei. Land.Bdeing XP~&l Ylyina No. PP-.c ontrol. testing technique (reprod~ing models).’cohtmp of c!le~k.NACA BbblJ. Piers~n. ..59.ls”as Me”asuredin t@e:NACA 20-Foot . Edwin P“o-:The Ae rod~ami. .. 1 . .. ... .: Additlonal #.A~roraft o En@nee. . tudinal stability. 5b . ... no. . 1776. 296..Gott.-1935. 1937. ventilation. Oct.. . . 1934.V~rloua Modifications to a Powered Moti. Kleg~n~l. . .of a l/8-Full-Size ~amio Model of the Consolidated XP4Y-1 Airplane . R. .. ”Dec.A. Newton A. ‘ Seaplanp.apl~e . flaps.: ~.C. .aplane:Wke-bTf ~el’ghts.~ng..am.”FQ~..Air drag.ats~ hydmostatims. .. .. . Aero. ... ‘ Theory of. vol.. 43. . .. . Tip .’..theWate”r-.takevof’f.’No. L3.horma’fi S.paraine!ers affecting . “. Bur.~o~~ on tie Dlreloti . pp. windshields... .NACAAGR Ho.“ . Jour. . Aviation. . Predlotlqn. . . effect .P~ng~..: . %7.‘ .xyder.No~”525. “DavidM.hlt.am ratlcj.: Effects cn . . 159-163.. Depth of step.pp..o? design.. .:.: Douglas A. . Wind Tunnel -“I? NACA TN. .@. 6.S..5y1~318... . ~. .: Se. . ’vol.:30’P.: aria’ ~nd “Linds~~ J. ‘J~” 19..”l“ength-be...1. .in Flying Boat Iigdro&*a*los. . p~npoising. spray strips. . tall extension. . .. on~ ‘Stablllt~of )+0. planing fins.. 691-717.L6wSneed Spray Characte.8.Bur.. Aero.wol.: flo. .aftlie. E. NACA MR. . . cross-wind lSnding.StabiiltyTests. r. ..l3artmsn. . . .: ~3pr~. . no.iscuskipn of the . 46. .. depth of step. L5Q28 . “. May 23. FLY’’JWG-BOAT “ HULLS “ Reslst&ame Tests of Two”Models Of Hulls for:a Large Flylng Boat (NACA Models ~-l . . John D. Scl.C~ksslcal . . XXXIX.R..qon’. . ‘NACA i~()~ stmlps.form.Porpolsimg.. ment tm.. ventilation.o”f’” power.%9...: h~.. AU::d:?35. . . .briffeyj ~~ J::..ristims of.l~”.. . .70.~~Drag of FlyingBdat ~ull”Morle. .Possibla :VOI. .Goldenba&”.“.R. . . . VI”.1 ~aworing the . 45. Maroh 3.and~~K-A). 10. . -General” d.. and Mas. 330-~2. 19~14. Develop41: Go~-e* A.no+. ~apray Boat. hetght bf Iiull. . ‘an@e of hfterbody keel. T. An Introduction tQ Se. Aero. Jour. lower-11.:. 1944.. 19~3. . ). . -. longl. Jones. Directio~al. NACA Ml?. .’. %CM.iL5F07~ 194~ ~1 . British A. and Storer.. pp.~.‘.I . F. tanks. Locke. acceleration. longitudinal stability ftrim limits). fmm of step. . tip floats and lateral stability. Angle of Afterbody Keel.-.. . 1941. Land. and Lina.: Tank Tests of a ~/8-~11-Si. and Woodward.: Investigation of Bottom Pressures and of the Effect of Step Ventilation on a Seaplarm Hull. Lindsay J. 1944. and a Pointed Step on Landing and Planing Stability. T3ur. NACA MRP %r. scale effect. A. s.-. Ventilation. (London).nethe Effeot of’Length of’Afterbody. -. w. resistance. S.(MAO.. moment of inertia. W.___ 4..Rep. . .. gross load. 1 to Detezmd.ze ~amto Model of the Consolidated Vultee PE2Y-3 Airplane with a Lengthened Forebody and Afterbody and Various Modiflcatlons of the Stap.: Tests of a 1/8-FuI1-size Dynamic Model of the XP4Y-1 Airplane ~0. 20.55 NACA ACR NO L5Q28 ----. . Land. F.I?. 14. aerodyn-io damping In pltoh.8.eamratio. March k..: Tests of a Dynamic Model in NACA Tank No. Aero. 3117. 53. ventilation. lo~gitudlaal stability.mmW-BOJW W8 . Norman S. 19h4. Dec.. ~. Jr. Marcus: Seaplane Float end Hull Design. ard Woodward. W.. Rep. mass moving vertically. Bur. J&. with Spray Strips . resistance. ..: An Analysis of the Main Spray Characteristics of Some Full Size Flying Boats. Locke.. length of afterbody.. Stevens Inst.. -.. Lengtht.NACA Model 143E.D.Aero. Ltd. form of step. Looke. Norman S. length-beam ratio. Langley.. Gross Load. depth of step. Norman S.. q 19. design. 1943. longitudinal stability (center-of-gravity limits). F. David R. Landing.. Teoh. 51. NACA ARR March 1943. *52. 1935. 173. Longitudinal stability. angle of afterbody keel. s~ray..Spray. 4ero. Sir Isaac Pitcnan& Sons. David R.. Essign principles and criterions. 191!L3. Land. Spray. pressure measurements.: General Porpoislng Teets of F’lying-iloat R’ullModels. Jr. Nov. S.. Oct. M-29.A)S. NAOA KR. NACA ARR No. No. longitudinal stability (center-of. Depth of step.: Take-Off and Landing Stability ati Spray Characteristics of Modifications of a l/12-Size Model of tlm JRM-1 Flying Boat NACA Model lm. . Aero. snd Land. 1933. spray $trtp. moment of Inertia.: First Additional Wind Tunnel Tests on a 0. 1941. NACA ARR.ravlty limlts and trim limits). Jr. 27. IioV.. Yawing. 57. Jr. Sir Isaac 59. S. Marvin 1. angle of dead rise. 19~3. $ept. Sept.. mass moving vert ftally. W.ne flare (rounded). Jan..Methods Used for the Investigation of Longitudinal1942. .. Munro. 56. NACA AFR. *61. (London). John A. NACA MR. warping afterbcdy. Roland E.068 Scale Model of a Revised Version of the Boeing Model XPBB-1 Flying Boat without and with Running Propellers. 307. Mp. Norman S. I . gross load. Pltman & Sons.: A Correlation of the Dimensions.: Some Yawing Tests of a l\30-Scale Model of the Hull of the XPB2M-1 Flying dat. 2h. Locke. plan form of bow. tip floats. Fllliam: Marine Aircraft Design. depth of step.chi. NACA MI?. Alr drag. engle of af’terbodykeel. longitudinal steps.: The Longitudinal Stability of Flying Boats as Detemlned b~ Tests of Models in the NACA Tank. ..Tfi%ctsof’power. *5& h?illlkan. and Loadings of Existing S. Locke. S.: Investigation of the Effect of Spray Strips on the Low-Speed Spray Characteristics of a l/8-Size Model of the Consolidated FB2Y-3 Flying Boat . 8. 1944.rch19~3. Spray.: Some Systematic Model Experiments of the Bow-Spray Characteristics of FlylngBoat Hulls Operating at Low Speeds in Woves. . Bur. 62. 60. Len@h of planing bottom. L5G28 55. F.56 FLYING-BOAT HULLS N~C~ ACR No. Stability Characteristics. Olson. Roland E.saplaneFloat@ and Flying-Boat Hulls. 19G3. NACA AFR NO. 3ZGh. Fred W. Proportions. S. Haar. Ltd.NACA Model 116E-3. hydrofoil under afterbody. step falring. NACA ARR No. Locke. Olson. F. Roland E. Jr. No. W. Olson.Clark B. Direnslons and loadings of existir~ design. 1943. GALCIT Rep. and Bradford. form. 3G06. length-beam ratio. 1935. H~: “ Longitudinal Stability Calculations of Sea lenes on Wate”r. Outman. TO. oenter-of-gravity llmlts. 1933. 27.: hslgn Criterions for the ~o~~~sions of the Foreboclyof a Long-Range Flying NACA ARR No. 10f( vol. NACA TN No. Chine flare. - 65. 19M. depth of step. 5f 5. proportion.. landings). XXYIs *o” 13114. John B. Commeroe. Olson. 3K08. “‘-”1~16-Full=Si.ty(trim limits.: The besign of the Optimum Hhll for a Lar et. vol.Take-t)ffand Landtng Stability. h70. spray.C. ~G28 57 FLYING-BOAT HULLS .. Position of oenter of gravity.. to Flight vol.: Tank Tests of’a ?bdel of a FlylngBoat Hull Hating a Imn ltudinally Concave Planing Bottom. Aero Digest. Take-off. 531. B. Parldnson. 60. lengthbeam ratio. J. 700 Parkinson. 6. Parkinson. I. no. 1943.: Tank Tests of ?t~del11-G FlyingBoat Hull. J 112. IX. -— . Mathematical analysis of the longitudinal stability of a hull at rest In tb water. 11-A.Long-Range Flying Boat. 1934s P~a ky.Dept. Longitudinal stab$li. Model No.A. ~. May 19. 67. 68. John B. 59. longitudinal ourvatureo 69. B. ~). 66. NACA TN No. no.” NACA ARR No. shape. spray. The Alroraft Engineer. J. Spray.. Resistance. longitudinal curvature. no. Naval architectural treatment. -. June 19389 ppi 53.N. Roland E. Parkinson. 1955. ITACAACFi NO. Resistance. Form . 32. NACA TN No. NACA IUR.A. .. Vernon: A Method of Calculating Seaplane Take-Off. Design. Parktnson.: A Camplete Tank Test of a Model of a Flying-Boat Hull . a method of’ calculating. 1944. spray.Sept.~ and Zeok$“Howard: Tank Tests of a . Parkinson. and Spray Gharaoterlstlos of a Powered Dynamic Model NACA Model 158. supp. 5L.~e Model ‘of the HK=l Car~o”Flying Boat.longitudinal concave planing bott~m. resistance. *63. John B. Spray.. 27s 1934s PPa &g. . — . . . depth of step.longitudinal ooncave planing bottom.C. Aero Digest. - . lengthbeam ratio. B. Roland E.haracterlstios of a Powered ~amic Model WACA Model 15(3. . J.: The Design of th~ Optimum Hull for a Lar e“”Uq-Range Flylng Boat.Take-Off and Landing Stability.: Tank Tests of a Model of a FlyingBoat Hull Having a Lo Itudinally Concave Planing BottOm. Vernon: A Method of Caloulatlng Seaplane Take-Off. May 19.neer.~sign. . Chine flare.-— -. landings). olson..on. Dept. 3K08. ... 531. 1943. —. . Sept. Longitudinal starelity (trim li. -. 1933. spray. John B. l?ACAMR.Longitudinal Stability Calculations of Sea lanes on %ate”r... Parkinson.. .: A Complete Tank Test of a Model of a Flying-Boat Hull . . me Take-off... Commerce. . longitudinal our~ature. IX.oenter-of-gravity limits...—. Parkinson. NACA ACE ~0. proporti.A. Form ..- . 10f( vol. Resistance. 70. . no. 1935. spray.A. 191JJ+. _-.. Parkinson. 6. supp.. 640 Outman. 11-A. — --- -. Howard: Tank Tests of a l/16-~11-Size Model of the HK-1 Cargo Flying Boat.: Design Criterions for the “ Dimensions of the Forebody of a Long-Range Flying Boat. Hi: . NACA TN MO. Naval aroblteotural traatment. F~CA TN Ho.: Tank I%sts of Model 11-G FlyingBoat Bhll. . resistance. d 112. Y 5 5.. md Zeak. Park5nson. vol... --.. 9). NACA ARR No. 66. J. 13h4.N. Resistance.mlts.. a method of’ PPa 539 5L 59# ~“ calculating. . . no. 32. XXWI. no. 15Q28 57 FLYING-BOAT HULL9 *63.-. . Mathematloal analysis of the longitudinal stablltty of a hull at rest in tlm water. parkinson. — . B. 69. 67. . John B..” NACA ARR No... 1935. 470.. 19389 q 65. Model No.“. John B. to Flight VOI. . . . 68. longitudinal mrvature. and Spray . 19k4.shape. The Alroraft Rngi. Position of center of gravity. NACA TN No. no. 70t Parkinson... spray. tip floats. 1934.:::. - . . NACA TN NO. Parldmson. Jsmes M. NACA ARR. spray. Depth of step. .. . porpolslng. Joe W. 58 NACA ACR No.. NACA Rep. ..-. . Bur. John B. I?ynami c Model of’Consolidated PB2Y-3 l?l@ng NACA Model 116 E-2. spray.< - . Bell.. and Benson.-& --.John R. .. 13... hydrofoils (used as stub wings)..NACA Model 117.C.. *74. 4Blh. plan fomn of step. Aerod~amics. and r)awson.. NACA MR. . .4 . .: Z. Resistance.. _.-—— . .- ~- . Parkinson. md Land. Norman S.. skegs and fins on tail extension (for directional stability)..NACA hdsl 116. 490.. Parkinson..: Tank Tests of’a 1/8 N1-Size _io ?60delof the Consolidated PB2Y-3 Flylng Boat .: Tank Tests of Auxiliary Vanes as a Substitute for Planlng Area. -— “ ... —u-. NAcA RB No. 1940.A. Aero. .. .. . Model 11O-M..x-r” . Consolidated Airoraft Corp.. .. .2. John B. 77.. -.s. .-.- . depth of step. . Parkinson. John B. .. Bur.A.-. take-off. -. No. 194.. Skipping. —.. 1943.N. Lo@ tudinal stability (l=di~). . . 1940. *75. . . Parkinson. 15G28 FIXING-BOAT HULLS 71.. Roland E... . 3127. 1936. DSU. HACA RB No.: The Landing Stability of a Powered Dynamic Model of a Flylng Boat with a 30° V-Step and with Two De ths of Transverse Step. NACA MR..: Tank Tests of a 1/5 Full-Size Dynamically Similar Model of the Army OA-9 Amphibian with Motor-Driven Propellers .. fo~ of step.C. . Effect of power.A.. ventilation. Aero. spray strips. John B.. Parklzzson. Jhly 12.: Additional Tank Tests of 1/8-Fu11S::.: . lmgltudinal stability.’. 76.John B. ....A. and Olson. 72. ohlnes on tail extension..::: ..:” Tank Tests of the 1/8 Full-Size Dynamic Model of tti Consolidated Model 31 Flying Boat with a Second Step .. 78. Parkinson. spoilers on forebody.. John B. Model without power facilities. . . May 15.--: . . Rolaad E.“ -. Dee.: Notes on the Skipping of Seaplanes. . Effeot of second step. NACA MR. ~3..-—. oenterof-gravity Writs and trim llmlts of the oonventtonal type. -“. John B. . . 1941. . -&. . Parkinsonj John B. Etc.. .: .. 543.. . Resistance.—. Model 40 Series of Hulls for Small Flylng Boats and Amphibians.: Tank Tests of N. and Olson. 19h .. .*+. A. . Model LO Series of Hulls for Small Flying Boats and Amphibians.: Tank Tests of a 1/8 Full-Size l)ynemicModel of the Consolidated PB2Y-3 Flying Boat ..C. 13. Parkinson. . May 15.: Tank Tests of N. IVACARB No.N. Joe W. Lon@ tudinal staMllty (landing). Skipping. James M.. Bur. tip floats.1940. John B. No.. 1943. Parkinscm. Model 11O-M.19~. — . 78. .: Tank Tests of a 1/5 Full-Size Dynamically Similar Model of the Army OA-9 Amphibian with Motor-Driven Propellers . John B.NACA Model 117.: Tank Tests of the 1/8 Full-Size Dynamic Model of tlm Consolidated Model 31 Flying Boat with a Second Step . 1940. *74. Parkinson. form of step.. NACA MR.. Effect of power.A. 543. Depth of step. spray. Aerodynamics.: The Landing Stability of a Powered Dynmic Model of a Flying Boat with a 30° V-Step and with TWO De ths of Transverse Step..NACA ?t?del116. John B. Parkinson..A. Aero. ~ 1934. John B.. chines on tail extension. John B. 76. ventilation. MC.. spray. spray strips. John B. Parkinson. Bur. Resistance.- .1. DSC. NACA MR. NACA ARR. -.. NACA RB No. Consolidated Aircraft Corp. *75.. plan fom of step. John B. 194. . Norman S... L5G28 FIXING-BOAT HULLS 71.: Addltlonal Tank Tests of 1/8-Fu11~~~ Dynamic Model of Consolidated PB2Y-3 Flytng NACA Model 116 E-2.. hydrofoils (used as stub wings). John B. and Olson. and Land. depth of step. 3127. take-off. ~3.C.A. and Olson. Roland E.—— —- . Roland E. 1942. 4B14. Effect of second step.-. spoilers on forebody. 490. 72. Etc..: Tank Tests of Auxiliary Vanes as a Substitute for Planlng Area. 1936.: Notes on the Skipping of Seaplanes. . . md Dawson. . Aero. JUly 1. Bell.2. skegs and fins on tail extension (for directional stability). NACA Rep. Parkinson.. longitudinal stability. and Benson. Resistance. NACA MR. 77. NACA TN No. John R. Parkinson. centerof-gravity llrlts and trim limits of the conventional type. Model without power facilities.. Parkinson..50 NACA ACR No.. porpolsing. Perrlng. chine strips. 3115. Aero. G. (Moscow). aerodynamic forces. 3. C. Alr drag of hulls. W. 82. 86..vedfrom a Streamline BOdY Series. P. 59 FLYING-BOAT HULLS 79: Parldns”m.: Full Soale and Model Porpoislng Tests of the Sin apore 110. Englneerlng. Trans. no. 85.S.. Trans. 2. waves. stability. Olsdn. R. yawing. no. Twin-hull flylng boat. np. 1931. A. No.S. no.M. spray. design considerations. depth of step.E. Aero. angle of dead rise (speoial). 127-137.: Design and lkvelopment of Seaplanes for Transatlantlo Service. pp. 193~. 4.. vol. air drag. lateral stabilizers.. Aerodynamlo and H@mxlynamio and Luoma. John D. 3. Eugene c.ght”ofbow.E. 4.. . resistance. rounding of ohlnes at bow..nel Tests with Airplane Fuselages and Flying-Boat Hulls. Sci. 81. Rowtdantzeva. A.-MC. E.’Roland-E. Boat Hulls during Taxil v~l.. A. Oct. pp.. E. Method of extrapolating resistance. Rohrbach. 1712. 80.. Rep. jet-assisted take-offs8 trim control. 190. angle of afterbody keel. Aero. MACA TM NO.M. ohlne flare.I.: Flyi~ Boat Design. and Hutohinson.c. 1935. Engineering. Trans. 1930. 285-2G8.R.. 1343.. vol. Sohrdder. British A. Perelmuter.H. NO. & M. Yawing. 169-195. .: On the Determination of the !Take-Off Chmaoteristlcs of 8 Seaplane. $$’ !UCA ACR NO. “Rumpler. Soale effect. 84.-moo 1931. NACA TM MOO f19. -Draley. July 19u . NACA ARR No. J.A. Adolf K. 83..Arvo A. L. A.: Wind-Tur.: Tests of a Family of Models of’Fl~fi-~BOlR&EI Derl. ~sign practice. Pierson. height of stem. longitudinal stablllty. .: Deteminatlon of Resistance and Trlmmin Moment of Planing Water Craft. oct.: Directional Stability of Flying Jour. . porpoising period. 11. Resistanoei hel.. .. . skegs. 863* 1938. side steps on afterbody. Jdhn--B.. L5G28 . H. ~G28 FL-BOAT HULLS 87. testing teohnlque.$ vol. Rep. take-off. 11. Sokolov. NACA). no.. R.: Experimental Determination of Hull Displacement. . 1932. ventilation. 1933.. vol. Shoemaker. 94. An extensive bibliography is included. 1931. .4.I. Length-beam ratio. James M. 58. C. pp. and Parkinson. pp. Sikorsky.que(RAE.: The Effeot of Trim Angle on the Take-Off Performance of a Flying Boat. and wlli Joe W. Trans. and Parkinson. Seaworthineas. effect of trim on resistance. Shoemaker.A. H7 Res/173. Shoemaker.A. trim indicator.: Hydrodynamic Properties of Planing Surfaces and Flying Boats. Rep. NACA TN No.C. testing teohrd. 1934.4. NACA TN No. A.: A Complete Tank Test of a Model of a Flyln -Boat Hull N. John B. 60 “ NACA ACR No.: The Development and Characteristics of a Lang-Range Flying Eqat (The S-k). Stout. I .: Tank Tests of a Family of Flylng-Boat Hulls.E.H. radius of gyration.—. Aero. 3. and WMte. 19~4. pilot technique. Smiths A. april 1935. Frederick P. Schuettel.: Complete Tank Tests of Two Flying-Boat Hulls with Pointed Steps N. 92.. flaps. 504. depth of step. beaching methods. 139-48. 95. G. 43. PP.S. oct*-Dec. 121-125.. MAEE. flooding tests and calculations.: SOEW Aspects of the Seaplane. vol. pointed step.A. general. 149.. 89. N. spray. 292. Jour. full scale. 93. April 194. resistance.A. Igor I. Resistance. 91. power. Discussion of practical design and operation of this fl@ng boat.. xxxIx. (MOSCOW). G. 486. 29. Feb. 4. A. James M. 1934. No. step fairings.A. ~!l.C. Longitudinal stability. James M.S.. Shoemaker.A. no. 263-281. NACA TN EOO ~ %~. 90. Trans. British Marine Aircraft Exp&rimental Establishment. John R. James M. NACA TN No. John B. 1934. no.% Resistance. Static tests of modsls. and Dawson.: A Review ~f Porpoisi Instability of Seaplanes. Ernest G. Resistance. Aviation.M. Engineering. Models 22-A ati 35. Yodel No. No.. 74-A. Nov. Ward. Parkinson. R. Part I.96. gross load. NACA TN No. E. . Longitudinal stability (trim litrlts). 103. J. ventilation (chlne)~ spr~yn 100. take-off comparisons. 648.A.A. Ebert. ~9. air drag. 19L .Effect of Variations in Form of Hull on Longitudinal Stability. 590. Aug.“43. plan form of step. NACA ARR. %7. Rep. Truscott.— . 102. Trusoott. spray. 1942. B. Towing Basin. RI vet heads. MACA TN NO. . ..A.:” The Inorease in Frictional Resistance Caused by Various Types of Rivet Heads as Detemnlned by Tests of’Planing Surfaces. Eme.. NACA RB.C. Tank of a Model of the Hull of the Short C~cutta Flying Boat. . 101.: Investigation of the Effect of Ventilation on the Flow of Water over a Rounded Chine. September-Ootober 194. Roland E. Starr. No. Avi8tionj “voi. posltlon of’step. Models 74. . spray strips. Thornburg. Floyd: Egdrodynami o and Aero- dynamic Tests of Models of Flylng-Boat Hulls Designed for Low Aerodynamic Drag . NACA TN No.A. 1938. angle of dead rise.2. and Parkinson.N.. length of afterbody. ventilation. angle of afterbody keel. 8. pp.: Report on Summary of Dynamio Tank Tests of a l/10-Full Scale Model of the XPB3Y-1 Airplane at the N. spray.no. Starr. center-of-gravity positions. 1934. depth of step. B.: Hydrodynsmlo Tests In the N. 1943. 150-153. 61 FLYING-BOAT HULLS .NACA ACR NO. Feb. 668. John W. Truscott. —. Charles J. Starr.C. NOVO 1942. . 1937.. Resistance.: The Longitudinal Stability of Flying Boats as Determined by Tests of Models in the NACA Tank. Trusoott. 1938. Resistame. Truscott.A. F. ~eslstanoe. P. spray. and 75.Jh. Kenneth E. Stout.Take-off. No. 98. 503.st G 9: Takeoff Analysis for Fly@g Boats and Sea lmmes. II . L5G28 . Starr: The Effect of Spray Strips on the Take-Off Performance. ZH-34-004.A. Rounding of chines. and Daniels.C.---- . J. and Valentine. 13. L. and Olson. and Maloney. Consolidated Airoraft Corp. frictional resistance. NACA Rep. Starr..of a Model of a Flying-Boat Hull. ventilation. 749. Ma 16. photography of flow. 2h3. Wolfe. L@. See also references 138. flow of water at the step. M.. . C. 1940. %05.: A New Method of Studying the Flow of the Water along thg Bottom of a Model of a Flylng-Boat Hull. Rep. 139. resistance. Longitudinal stability (lower trim limitT . depth of step. L5G28 FLYING-BOAT HULLS 10)+. Kenneth E. Boeing Aircraft Co. effect of shape ~f wetted area.62 NACA ACR No. NACA TN No. No.: Longitudinal Stability of the Seaplane Model YYBB-1 in we Planing Condition. D-h020.Ward. ActIon of step.1942. and 264. 254~ 256s . 26o. 589-603. Cambrld e Phil. May 19420 Planing surfaces. NACA ARR NO. “. Plsning theory.--. pp. -:~~.: The Effeot of Dead RIse upon the Ht@-Angle Porpoising Characteristics of Two Planing Surfaoes in Tandem. Benson. L5G28 . . 67-85. and Part II~ VO1. 1943. E. Proo.oa of a Planing Surface Representing the Forebodg of a Flying-Boat Eull.. Jan.. I. . James M. . and F“nihofher.— — . Meoh. complex transverse sections.--. . 110. Fifth Int. Oot. ~y 1936. James M. and Lina. 47k-477. 3L08.. --- --- --—. NACA ARR. 1938). 63 106. . pp. stability derivatives.. 2. q 108. Soo. John Wiley & Sons.— . Benson.PLAN.t The Porpoising Characteristi.. tall area. and Klein. Cambridge Phil. pp. Bollay. Anton: Methods and Charts for”Computing StaM lity Derivatives at aV-Bottom Planlng Surfaoe. pp. ITACAACR NO. Green. 1 39. theory of porpoising. Planing surface.—— . wing. Milton M. . NACA ARR. James M. 107. “E.ING SURRACES--~ . looation of oenter of gravity. Ino. f Cambridge. longitudinal stability (trim limits). Lindsay J. 109. “ Green. “ vol. . Proo. A. pt.. Mass.. XXXII. James M. A. moment of inertia. 19~3 Angle of dead rise. Planing theory. 1942. angle of dead rise. William: A Contribution to the Theory of Planin Surfaces.. XXXII.: The Effect of DSad F!ls e upon the Low-Angle Type of Porpoising.. NACA AFR No.. 1936....: Note on the Gliding of a Plate on the S-urfaoeof a Stream.. Appl.— -u=. angle of dead rise. longltudinal stabtlity (trim limits).. VO1. depth of step. Cong... Plming surfaces. 3F30. pl~ing sUrfa0e8 (theory? . XXXI. 111.“ . Oct. longitudinal stability (trim llmita). Soo. radius of gyration. 1935. pt. ~ 5-252. : The Gilding of a Plate on a Stream of Finite Depth. Proo. 112. Benson. Benson.. Planing Planhg of dead James M.: Planing-Surface Tests at Large Froude Numbers . R. resistance. NACA TM No. Shoemaker. 661. skin friction. planing surface.A.. Perelmuter. —— . Resistance. 11. 19~.H. 116. 1934.anlpgProcess on the Surface of Waterg NACA TM No. surfaoes. .Airfoil Comparison. angle of dead rise. --.and Johnston.. w.-.—. 848. scale effect. reslstsmce.: Tank Tests of Flat and V-Bottom Surfaces.: Expe&. (MOSCOW).. W. resistance. - 117.. 1935. spray. G. A. W. resistance. W.: Hydrodynamic Forces and Moments on a Simple Plsning Surfaoe and on a Flying Boat Hull. L.- ———. Perrlng. NACA TM No. A. boundary layer.-— . Pianing surface. TN No.-— —. Sottorf.I. 48. 509. & M. chine flare. . 1934.. pressure dlstribution~ See also reference 12. spray. 16~~. Sottorf...: On the Profile of the Disturbed Water Surface of a Planing Plate. 1935. Sambraus. 115. Planing surface. L5G28 PLANING SURFACES 113.. NACA TN No. C.R. WACA T?dNO. Planing surfaoes.—.: Analysis of Experimental Investigations of the P1. 118. pressure dlstributlon. No. angle rise. British A. testing technique. 1061.!+. scale effect.. 119. 1938. A. longitudinal curvature. .: Experiments with Planing Surfaces. 1932. Planing surfaces. scale effect.ments with Planing Surfaces. —. 64 NACA ACR No. 739.. Sottorf. design data for planing.—— .C. pp. 1937. 1. No. Effect of trl. &59~ Edo Aircraft Corp.: Twin-Float Seaplanes.E. 12~. 123.S.. D. 1941. Feb. V. Billett. . 1943./. Bur. Jhlian D. rivet heads. D.: Study of Change in Water l?esistanoe due to Change of Trim.: T~k Tests of Two Floats for HighSpeed Seaplanes. Commeroe. Rep. vol. H. 1. NACA ARR No. . 122. Air drag (float seaplanes).S. H. .21.t Alrplme Al”rworthlness. surface roughness. Dept. seaplane floats. %26. Pt.. 04 of Clvll Aero. Analysis of tank tests. Robert N. floats (full-soale). . Bladen. Aero 1719. m on resistance. L. ~ti 1933. Dec. 1930.Anon. 473. Rep. British I?.- 65 120. 831. asymmetrical forms. 49.: Alrplans Alrwortbhesso Pt. M-56. Edo Airoraft Corp. . twin floats (test of one). B9n. Dec.: WindTunnel Tests of Four Phil-Scale Seaplane Floats. A. Nov. Converting landplsne into seaplane.Cowley. No. 1941. 1941. Resistmce. PP.‘ ‘. spray. yawing. Aircraft Engineering. Dept. Alr Commerce. U. 1933.. 3G15. ~Z5. Joe W. 6..: Method of Computing Corresponding Speeds. Manual. o step f’airings..Loads and Feststances of Plardng Bodies. resistance. Nov.. * of’Clvll Air Regulations.alr drag. 20..: Tunnel Tests on High-Speed Seaplanes. and Maynard. Aircraft Engineering.: Tank Tests on Speolal Clesn-Running Floats for a Twin Float Seaplane. 1. . no. Twin floats. 1941. 247-2~@.. W. Anon. No. 12T. resistance. No.NACA i4R ..+..28. II. Conway. H. CAA. vol. seaplane floats. Commerce. Bladen. ~G28 . NACA TN NO. no. Oct. . U. Air drag. 1. 9EAPLANE ~OATS ----. Anon. Rep. 23. J. L. 1927.Collected Renorts on British HIRIISfieed Atrcraft (Introductionby W. Cowley. WL36.. 12-~. length-beam ratio. Rep. NACA TM NO. Feb. pp. 130.—.3. 23. 132. 6. 1300. W. 131. H. tsnks (HSVA). IL: Seaplane Floats and Hulls. 1933. 719. L. 1927. to Flight. form. Part I. spray.. 4. Hermmm. 19]’h. Luftwlssen. 131L. Meyer. Antonio: I?ydrodynamlcTests of Models of Seaplane Floats. Design of seaplsnes. The Aircraft Engineer.S =d Ribnitz. step. XO1-122~. Miller. 1933. Lockheed Aircraft Corp. Aug.. H. L5Q28 SEAPL’J. TbiS report contains the results of tank tests carried out at free-to-trim ”condltionson 17 hulls and flcats of various types.: Der Luftwiderstati von Schwimmern und F’lugbooten. No. Twin floats.ers: 1927 Schneider Conteat . H. G. and Klcess.1928. H. Eula.C. No. mneuverabillty. General discussim of early seaplanes. Herrmann. (Available as British Air Ministry Translation No. British A. B. NACA TM KO. ~. 770. Twin floats. 1935.: Report on VSO seaplane Studies. Gothert. resistance. track (distance between floats). Twin floats. XXV. Parklns~. lg. w. NACA TM No. Herrmsnn. March 1939.: Seaplane Floats and Hulls.—- 1 66 NACA ACR HO. supp.: Notes on the Desi~ of Twin Seaplane Floats. W. NACA TM NO. Part II. pp. Kempf. no. 10@. L. &M. “ R... angle of dead rise. h27. spray$ 135. and Otb. track (distance between floats). 137. vol. design considerate ens. One specific conclusion is that the best models have a maximum relative resistance not exceeding 20 percent of tb total weight. Cowley). 133. ) Air drag.R. 101-107. 1931.: Tank Tests of’Twin Seaplane Floats. IfAcATM No. scale -effect. 1261. discussion of tip floats and their failures.86. L26. Discussion of structural design and performance. . : Dimensions of Twin Seaplam Floats. ~:r..Ni WOATS Trophy 129. spray. resistance. Roland E.‘fairlng). resistance. spray. NACA TN NO.” See also references 57. MACA Ml No.! . liACARep.- .. Resistance. step (pointed and transverse forms. of Rivet Heads on the Water Performance of a Seaplane Float.stabllity. IW’2hACR NO. NO. F. B. The Fknmid Press Co.Parkinson. L. . and House. Models 57-A..A. Design of floats.: The Design of Floats. 139.:. NACA TN NO.. L5A31a.-.: Hydrodynamlo and Aeznd~amic Tests of Models of Floats for Shgle-Float Seaplanes. design of floats. 1938. and Lipson.. and House. Jr. O. 142. o. Par@insom. spray. w. Holden C. Aero.A. lf+O.5. 1929. action of step. %4. reslstanoe. Bur. resistance. Models l-D. Richardson. NACA TN NO.. Rivets and surface roughness. NACA 2348.. 65i .: Aircraft Float hsign. Parkinson.Thompson. 61-A..C. 716. 1931. John B. form. @-E.: Hydzzodynamio and Aerodynamlo Tests of a Family of Models of Seaplane Floats with Varying Angles of Dead Rise. 1928.. spray strips. 73.Tasta to Show the. 1945. 57-b.A.s Water Pressure Distribution on a Twin-Float Seaplane. Sottorf. R. and 73-A. 1938. Jolm. spray. ~~AcATM NoO 639.Effeot . 860. 328. angle of dead rise. and 256 “ .. 1938. 43. Angle of dead rise. Olson.C. L5G28 67 SEAPLANE FLOATS Tank . . 154. boundary layer. Seewald. 1~39. Air drag of main float and tlp floats. air drag.longitudinal steps. lo. 1.A. N. Stanley: Clean-Up Tests of the SC-1 Airplane in the Langley Full-Scale Tunnel .. J. frictional resistance. and 57-C.B. 657. Length-beam ratio. take-off. Herbert A. General. Rufus. NACA TM No. . air drag.TED KO. lmpact.138.!+)+. N. Wilson. Friedrich: @n Floats and Float Tests. James M.: Transverse Stability of Seaplanes.A. 153. displacement. NACA ~. Air drag.: Specification for Transverse Stability of Seaplanes . 51-B.1936. Tank h!~del70). R. 151. Tip floats.A.: T~k Tests of the Martin No. spray.. Feb. 156 Flyin&-Baat Model (N. Benson. Aero. tip floats. vertical locatlon of t~p floats.C. z5G28 %)46. John M.: Hydrodynamic and Aerodynamic Tests of Four Models of Outboard Floats (N. W.A.: The Value of Retracting Wing-Tip Floats on Flying Boats Compared with That of Retracting the Landing Gear on Landplanes. 51-C. “ 48.70Anon. April 23. hydrofoi1s. and B~ttle.R. NACA TN Na..C. technique of recording direction of flow along bottcm.Edwin P. effects of variations in position of ~tub wings. TiP floats. 7. A~. & M. Ccombes. 1755.C. md Benson. hydrod~namic lift. 19~B. Anon. air drag. Joe W. Aero... 1941. twin flnat. L. resistante. Arthm L. dynamic lift. 57. static transverse stablllty. hrov. Bell. . 19h.: Tank Tests of Codifications of a Model of the PBY-Type Outboard Float .A. and Hartman. and Drumwrlg>t. 1936. .C. VC1O V= no.NACA Model 104 Series.. NAVAER SR-59C (superseding Submerged SR-59B).Displacement and Location of AuxtlimyFl oats.. NACA MR. 20. Tank Model 72).A. Fi. Aircraft Engineering. D.: Notes on Stubs for S3a~lenes. Jsmes K. records of direction of flow along the bottom. %52. Aero.ar.Sept.. z76. 1933 p~a 271-273. No. I h50.A. John R. Models l-A. Dawson. Bur. and 51-D). 1936. 194h. Tank tests of modal with stub wings. June 5. Allison. .. British A. Dawson. Track (distance between floatsJ. NACA MI?. P. John R.68 LATERAL STABILIZERS N1=CAACR”No. yawing. Bur. 16. 1~. NACA MR. General tests of model with stub wings. methods of retraction. * 1~9.: Tank Tests of a Model of the Hull of the Bnelng 314 Flying Boat (N. : Some Design Criterions for Wing-Tip Floats. Tlp floats (streamline body with hydrofoil).A.: Prelhlnary Tsnk Tests of an Outboard Float Having the Form of a Streamline Body of Revolution Fitted with a Hydrofoil. Afrcraft Englneerln .: Tank Tests on a Streamlined Wing Tip Float with a Hydrofoil Attached. 1945. stub wings. I?ACAACR NO.1*. Llewelyn-Davies. Bur.C. March 5.Brttish A. Feb. 19L3. q . A. 19~. Fehlner. hydrofoils. No.: The Design of Seaplanes..E. S. W. L5H02. 1 38 Revised). resistance. I.Lero. 202-20E Tip floats. W. 1560 Gouge. 161.NACA ACR NO. T. 1570 JacC)bf3. Tlp floats. C. *159. A.: Effect of Protruding Gas Tanks upon the Characteristics cf an Airfoil. NACA MR. King. F.A.. lift. Aug. 1926. structural def’lectlon due to loads-on tlp float. NACA ~ No.. Jones. Douglas A. Eastman N. lateral stability. . 1924. Dee. Lnalysis of destgn orlterlons.A. Rep. NLCA m-lHo. 23012 with Various Protuberates. !Pwlnfloats. (NAcA paper to be considered for publication as RBJ . Bur. hydrofoils.: Experiments In tie Compressed Air Tunnel on the Aerofoil N..: Static Stabillty of Seaplane Floats and Hulls. Brown. . 249.C. 4 155. *160. 4D06.4. design of float structure. 5661 (Ae. *162.. D. 16. Douglas A. Diehl.R. British R. . pp. resistance. Aero 1910. end Miles. Leo F. 158. twin float. Up floats. mng.: Tank Tests of a Model of the PBY-Type Outboard Float with ~dmfolls. Of Interest in the retraction of tip floats. 16. . alr drag (tip floats). no. 19z2. Annie Mary: Comparison of Current Speoifioattons with Actual Static Transverse Stability of 15 Flying Boats. vol. P. 194. lift. II. 1930. Useful for estimating air drag of partially retracted tip floats. Aero.. NACA TN No.. Matthews. 183. L5G28 . 69 LATELiL STABILIZERS .. J. R. and olson. 51. . ~~..40..%63. . . —-.A. Howard: Hydrodynamic Lift Characteristics d ‘Threel/10-Size Models of Outboard Floats for the E(K-1Cargo Flying Boat. 19~. Boeing Aircraft Co. L5G28 1#.— -—.. . Commerce. 18. . See also references 6.. ..-— . 59. ... 19. Roland E. hydrodynamic lift. . Aug. 32. . . NAOA ACR No.. 74. Dept.70 .. liACAMR. May 16.- . Tlp floats. Zeck. 19.. Kenneth E. .A.~ STABILIZERS . Ward. .4Flying Boat N..c. : DgnamirJ T6sts of a Model of the Boeing 31. Stabillty-tgsta with and without stub wings. NACA MR. ati 251. 244. Model 108. Shaw. aspect ratio. zA-29-027. full soale.-. G. pilot teohnlque. R. L7. mooring std. R’.@3 Bowen... Rep. Carl. E.. AssistealTakeOffs WIth Jet Pmpulsi on. 1940 flaps. Norman s. . 7051..J~. and 254. John D. .. 167. Part I.. 64. 106. See also references 20.—. H/Res/143. Model PB2Y-3 Airplane No. 53.-. liACARB No. NACA ACR No. 166. aerodynamics. .. W. N~. . .ng Bnats. spray. 3E13.. Consolidated Vultee Airoraft Corp. John P. Of Interest regarding spray clearanoe. resistance. 1945.. No. Take-off (calculated). 176. Hofeller. 170. 1944. I?ACARep. . B.. -.: Summary Flight Repofi . E . 46.: The Calculated Effect of Various Hydrodynamic and Aerodynamic Factors on the Take-Off of a Large Flylng Boat. Parkinson. . A. Wenzinger. Rep.. wing setting (incidmce).. 78s 97s —_ — _J.: Effect of’Powezwd Propellers on the Aerodynamic Ctiraoterlstlcs and the Porpolsing Stability of a Dynamio ltodelof a LongRangeFlying Boat. end Bell. J. . . Tests on the Saro 37. %65. R.: q?estsof Round and Flat Spoilers on a Tapered Wing In the NACA 19-Foot Pressure V?lndTbnnel. 169. . . q 168.Lsnd. Olson. M. 801. NACA TN No. Paul E. Jet-assisted take-offs...: The Calculated Effect of Trailing-E5ge Flaps on the Take-Off of Fly~. 702. end Campbell. British Marine Alroraft Experimental Establishment.. 1934. . yawing. ~. take-off.. . Purser. March 8.... No. operation and design of jet motors.. .: Experimental Verification of a Simplified Vee-Tall Theory and Analysis of Available Data on Complete Models with Vee Tails. NACA TN No. powered propellers. Aerodynsmtas. J... . Lmgitudlnal stablltty (oenter-of-gravity limlts). 510. Jilly19L1. Effect of flaps on take-off. 171. Flaps. L5A03. 1941.: The Effect of Flaps on the Take-Off of Flying Boats. J. and Allison.. 1943. Planing flaps. P.. Charles J. unconventional forr.NACA Yodel 133..Kenneth L.: Tank Tests on the Resistance and Porpoising Characteristics of Three Flying-Boat Full Models Ecpipped with Planlng Flaps. . and Co. Locke. Bur. Bur. Daniels.NACA Model 1. Aero. June 26. . March 31. NACA AIW?No. The Aeronlane.NACA Models 16 B and 165c. W.. longitudinal stability. %77. vol.ombes.. Charles J. and Barklie. 19411. Cox. Daws?n. Lsad.: Speclfio Tests in NACA Tank No. Roxbee.: Tank Tests of l/10-Full-Size Model of Nevy XLRQ-1 12-Plsce Eloat-Wing Seaplane Glider .. The Aeronautical Board.Planing surfaces. and Woodward.. porpclsing. NACA KR. 3F15. %. spray. Aem. 1943. Carter. I~crmanS.nal ?-4 stabtlity (trim and center-of-gravity limits arxl landings). no. 1. H. flaps. Aero.: The Hull-less Flying-Boat. . Spray9 yawing.”July 7. Spray. stability.75. ~r. 2 of Two Models of the Kaiser-Gar Wood Flylng-Boat Hull . John R.NACA MR. and ?!adlin.: Tank Tests of l/10-Full-Size Modsl of Allied Aviation Corporetlonfs 12-Plaoe Float-l!5ngGlider . Daniel S. spray. Jean A. L5G28 UNCONVENTIONAL CONFIGURATIONS %72. resistance.arched bottoms.. flaps. 1937. March 27. resistance.NACA Models 157A and 157B. 19. Jr. F. pp. 173.: Spray and Stability Characteristics of a ~amic XOdel of the PB2Y-~ Airplane with Transversely Arched Bottms .L. LITI. David I?. NACA MR.— . Dec. ~0.. Arthur W. * 174. resistance.. 178. NAGA MI?. 1384. 72 NACA ACR HO. skipping. 1942. “176. Tunnel bottom. Iongitudi.: Preliminary Tank Tests with Flaning-Tail Seaplane Hulls.. 19t!L3. S. . See”also references 3 and 260. fiACAARR No.!40. Float wing. 6~~-380. 19~2. Analysls of the efficiency of a ‘ planlng surface fitted with a hydrofoil. shape).cavitation. 217. . Ships. 1931. .: An tivestigatlon of Hydrafa31s ~n the NACA Tank. Sonderdruck der Vexihandlungen des III Ihternationalen Congresses W techni. 185. T. Adceret. L. no. 1937. Norman S. ~nson. J1937. Hydrofoil systems. Benson. *182. I . *180. NACA ACR. 4181. 1942.. E.: Tank Tests of S?alp-Propeller sections. NACA TM yo. 3K02. to L~A&ronautique.Effeot of Dihedral and Depth of Submersion. Hydrofoils (dihedral. stability (hydrofoils). NACA MR..NACA ACR .A. v. interference effects at jurmtures. cavitation.stiesof Various Hydrofoil Systems for Seaplanes and “Surf ace Boats. Coombes. 1942. A. NO. B. cavitation. Rep. 61-69.: Prellminsry . cavitation. NACA RB No. supp.British R.—.stable~ L~A~rotedhnique. 174.”P. 1943. depth of su-bmerslon. 179. 14. J. Nov. Tests to Determine the Dynamio Stability Charaoteri. James M.: Experimental and lheoretioal Investigations of Cawltation In Water.. Gruqberg.: Note on the Possibility of Fitting Hydrofoils to a Flying Boat Hull..: Einfluss der Cavitation auf die Leistung von Schiffsschrauben. No. 1A.. Bur. Douglas A. 1 ..E. mtz. Strut Robert F.. 1078.: La sustentatlon hydrodynamique par ailettes immerg~es. . Land. “ no. and Land. and ~.40. James M. ??orcemeasurements. Essals d~un syst~me osustentateur auto. James M. PP. “ IW28 HYDROEQILS 73 .sche Mechanik (Stockholm). Hydrofoil systems.. and Daties. Benson. April 16. and Havms. 1945. Norman S.A. 183. J. Sept. Hydrofoils. 16e annee. ti~~~fO~gA-M~cA BU. Land. R. Norman S. Norman S. 1. 194.Plfteen Years of Naval no.and Havens.2 ~droNat... June 10. Res. Avlatlon. Aero. 192.: Tank Tests of a Guidoni Typ SVA Sea lane Float with Models %7.. L~d. Force measurements without cavitation. Section oharacterlsttos.A. 6. %89. Aero.. 19i 0. . Jour. NACA MR. June 1:.: Tank Tests”of a Grunberg Type High-Speed Boat with a Lifting Hydrcfoil and Planing Surface Stablllzers.. NACA CB No. CIT.1 Offl~e Scl.. Land. 19~. Hydrofoils (on PB2Y-3). July 22. Guldonl.Bur.S. design principles. and Dally. NACA Models 10 -A and 103-B. James W.3. and Suvorov~ L..: Tank Tests of Two Ogival-Section Hydrofoils. Hydrofoil systems. Land Norman S. hydrofoils. Norman s. see.. Aug.2. Def. Eur. 188. q90. no. cavitation. vol. Robert F. spray. VO1. and Dev. Jan.s-209 section. 67B. NACA Ml?. Experimental and analytical treatment. “ * 191. 67A.: Seaplanes .: Charaoterlstics of an NACA 6~.s-209 Section Hydrofoil at Several Depths. force measurement. Khapp. April 16.div..: Preliminary Tests to Investigate Low-Speed Spray of a l/6-~11-Size Dynamic Model of the PB2Y-3 with a Hydrofoil . 1928. Sept. 1942.~~~ltation Character stios of’the NACA ~1.4.: On the Destmctive Action of cavitation. pp. A.NACA Model 131-X.. Ships. 25-64. * *193. 25. Hydrofoils . lqh. 1943.. 205. L5G28 HYDROFOILS “ 186. XXX II.74 NACA ACR NO. h95-506. Phys. Jour. Norman S. photographlo studies’of cavitation. NACA MR. Corn. Robert T. Land.: Force and . Aero. Experience with fullsize seaplanes having hydrofoils. 15. 3E27. 6. Kornfeld.!J. Appl. 6. pp. Lina. %87. Bur. M. Hydrofoils (Guldoni type).characteristics Or NACA 66. Res. Lindsay J. .5 -21@ti. April 1. . ‘. & Sons. . .P. . .~~elimi~ry Tests in the NACA Tank to Investigate the ‘. “Hydzwfolls. “’”GiP.f TM ~~. ?-. . 20.. ““..“ “ .. 200. pp.. . 1941. . ~ 1~...le ‘Mess.a racing seaplane with hydrofoils. . cawltation.>.““‘‘. .“1940.-. “106. . .. . .(Washin@m).T.Heft 7.ReederelI . . hy~dfiofal~s.@@rg.. B. Giovan~: . —-— . w~m . Hafen~. .. . ~ 198.: Prellmltiary @nk.. ~. .. . . 1~. 1944.O... 691. ~adlin.~ $@.. I.: Das Tragflachenboot.) Cavitatlong. . Oot.* .: . HTdmfoil ‘boat.. (From Werft. .. resistante.:ca’~ tation. . 87-90. .d~ng . Translation No.pp. H. 1932.— .. {Cambridge. .
[email protected] Reederei ... . PP. pe~a. Nutmmhi . :’.~roduotlop. R.. : .” “‘ ..deielopmentof.... ... 20. Inc.i .0. . Reprinted from Smithsonian Report for 1919.~-h. Heft ~. .~i .$dhrg. 1937. O. .O.“Bras d~Or Lakes. .. “.’ NACA ‘ACR. ‘Hydiofol IS.am ~asl@~: ..pp. . Cong. . App.orieq on th . .Experitients ‘ 1.. i. .. . 614~~16. ~:... planihg-t”hi 1 princfple. F. . . -damentdl Charac~etistics qf Hy$rdfpils... .ng-~all Sa@lane Hull. . .wlth F@markEble PossibiIities m.~ . “ISACA ... . . . . . ‘1939. . q Some Ideas on Raoing Seaplanes. 295-299.TMN~.- . Proc.# ~o=~:le~ . Nutting.: Cavitation Study by the . . .. “.. 106-109. . . 1944. .. .. with a . Cavitation “(thetiry). 195. Peters. Fifth Int. . Tietjens.. ‘%2010Ward. EM tish Mitiatry of.:. .velbp”ed.ure~nt9 . ~cav~tati on. .“” ‘~d La~ . . . . .1. ”Gr~am Bell!s I@borat.. . . 1 -—. ~’ ‘.Hydrofol~ on a Planl. . Walohni”r. and Rightmlre.. .... hydrofdi1s. “Tests Of models. .ALrcrqft .Hafen.. Dr. 1921.. .:NACA . ~o~. G. 1937.“Mass. ” . at . 197. 75 HYDROFOILS “$brcek ‘on Slotted Blade 194. Un&sqal fozhns. .” NACA’ ‘RB NO. . 18 . .. John Wlle$ .. S#~t. ... *399.uf” Profiles under Cavitation. . .~ c28. c Experlr’entalend ttioretical investigations of hydrofoils for use on surface boats ~d airplanes. ApriI 10. hydrofoils. K~~riet~ ‘~.” Pp. “ Ni@k” ACR ‘No: LIjG28 : . .-.VlbratoryMethod... .Wi Ili. .: I .: ‘M~~s~ement.Meoh.. ..:. . k6nneth L. “ pr@l. . .. 1938)..Publipat@~ 2~95c. . llft-drag ratio. . : se..”195. . Hutchlnso. No.205. Locke. .Sea.trim . BrZmm.aplane8 . Yor. .- . reslst~ce. . Idsnly. .: . ‘.NACAACR NO.“. 1942. . 76 . 1~. Aero. pp. ... .t “ “’ Aoron~titics Council.—— . m. at mooring. Preliminary Resistance Tests 210. . .~mt. Natfonal .fic~-(Newo OP6 . . 211. U. H . Jr. q . ~. .. H/Re s/178.. L5ci28 -. . . Maintaintig. Commerce. . 32. 208.. .— I ..: . . Bbali..ter No. ~FTIXYPINGAND:HAiiDL~G . 23. . 3.”:. . . 19~. n. 288-291. .Shallti Water of a l@3-Scale Model of the . . . . U. .Maneuvering>.. ‘Commerce. Aylation “Cir@ar’l@t. General.k).’. W.. BritlSh Marina Aircraft ExperimelitalEstablishment. Tech... ... mpt. ~pti Of . . .. . . tie Use of the ~rim-~gl~ Ihdi207. Dept.. Gri&6~””l?.. . HolderiC. 066. Richardson. 923. indicator. . . . 19400 Geperal.Part Four 206.. .. Piti+ I%blishtig Corp. Cram”. . .1944:. :. . water. Wellwood E. . pilot” . Jour. ‘. Handling of seaplanes . Tech. D. F. .” ”.” 194+!. “ . . . ~pildt technique. Rep. .. depth of water.. cater . A. Anonn: “‘. . Rescue 2“03 . 1937. D~ie 1.Jo L. . Operating. q See also references 40 and ~. . May 1937.S.: in.. Open ‘Sea Seaplane . CM.W. . 1945s . t “.: Note on the Valuq of.. .Kelvin N. No. . F.. .fo”r Seaplane Take-Off. .:Hull of the XPB2K-1 Flying Boat. . - 209.“. “ : .S. pilot ~ technique. Development “ Note No. and. ‘ “ . .Emargency Take-Offs in the q Na~ Dept.Jack R.Opirationa. .:9-$ Down-s”welllandtngs and take-~ffs. Pitch Propellers on Seti@nes. ..GQi@. .:”-The Establishment of a “Restricted Area for Seaplane ‘Operation.tech@~ue. Jr. Stevens rest:.No.Reversible Rep.~. Bu1l. Jqly 17. M~ual. 4. Alr Sea Re?cue Agsjney . VO1... .. . 7... No.. Jsna +?U* Length-of take-off. . NACA TN Ndy. Feb. . S.‘“J.-Seaplane F~ylng. “ (Washington).Charles.n. ~ACA).. . . Sci. Daniel J.. . Civtl pilot ‘Tra~n@ C. . 2Q!+-penson... operation of seaplanbs. . . “.. Wagner. .ofFlying Boats ~lth Special Reference to Porpolsing”and Skipping..”. no.: Flying Boats. xmdc”
[email protected] M: : Filotin~ . .. “.~ “ Advisory Memo.. CAA. Sept. . ..” . 212. A. No. Impact normal accelerations. . Data on imgacts. Determination of upper MmIts to factors required on seaplan”e structures. and Aoo:leratlon Measurements on an XPBS-1 Flying Bureau Project . Bur. Darevsky. S. Batt9??EIOI’I -24. 28. S The EACA Impact Basin and Water Landing Tests of a Float Model at Various Veloolti-esand ‘We. -— IMPACT. Taylor Bodies. 3160.lghts.: Determination qf the Stresses Producsd by the Landing Impact in the Bulkheads of a Seaplane Bottom.. No. -tish A. NACA TM Noc 1055. Navy. M.D.LOADS 213. 1941. Conversion of results of mcdel tests to full scale..— . The David W. Measurement of’normal accelerations and change in attitude during Imlpaot.E. 77 . %15. NACA MR. 8CMO NO. Trsns]..: A Theoretical Anslysis of the Impact of’an Elastic Body on Water. 216. 19!+4. G. F/Res/lG7. Rep.. Jones..-. JEUI. E. 35o6. L4H15. M.clplesof similitude.: Measurements of’Aooelerations at Different Parts &f a Boat Seaplane during TskeOff and Landing. W. British Matins Aircraft w~perimental Establishment. Abel. V. Hathsway. Take-offs and landings in choppy water..26. #. fllght-path angle. 1829.. and Blundell.II(3y A. British R. ~18.: Force and Pressure Measurements on V-Shapes on Impact with Water Compared with Theory and Seaplam Alighting Results.ug. .R. Model Basin. R. T.: Typloal Pressure. .C@S 1938. Stress. ~?OVa 1943. . design loads. v.A. Fagg. 219. Jdly 1941c Preliminary calculations on the Impact of an idealized elastio hull on water. ?J. 1938. Rep.”Aero. R. C. Rolf: Experimental D9termdnation of the Hydrodynamic Ircrease in Mass in Oscillating ation 118. p sld. 217. Prir.NACA ACR No. E. 1944.No.. Brahmig. S. Comparison of data with tb. E. 580. Douglas. Rep. 1638. Mathematical treatment of jmpacts considered as functions of the accelerated whter mass end hull elasticity for seaplanes taking off and landing in rough water. Comparison of teat results m-d computed results. Wilbur L. E. 1894. Maude A. No. 611. W. . Engr. NACA TM NO. 222 Kreps. of Impact theory. K. 1046. 1943. Ruth Lee: Acceleration Measurements.: The Impact on Floats or Hulls during Landing as Affected by Eo~tiGmWidth. *227.R. & M. British A.1951.5s An extensive- .: Experimental Inveatigatlon of Impact in Landing on Water. L..eoratical results. and Cushing. and Irwin. bibliography is included... Brief summary of Impact theory. Determination of limiting hull width as a function of impact forces. investigation of +he physical nature of impact on water. NACA TY NO. Description and results of extensive tests on flat and V-bottoms. E. 225. NACA TN Nc). 1936. R.1 ACR No. T.: Anal sia and blodifi~ation of &eory for I:mocct oT Seaplanes on Water. G. L5G28 IMPJiCT LOADS 220. perfection of experluental procedures. R. No. C. 1807. and Davies. H.. 624... 22f+. Martin Co. 19~14. Review and analysis Mewes. Paine. British A.R.. 221. one gross weight. Pabst.: Measurement of Water Pressure on the Hull of a Boat Seaplane. MWO ‘223. 1935. T. wilhg~m: Theory of the Landing Impact of Seeplar. 1930. 19~g.es. Jones. id!. .: Measurements of Acceleration and Water Pressure on a Seaplane When Dropped Into Water. Stafford. Jan.C. Suggestions for future rec9arc”n. R. wilheh: NACA IIMNO.I 78 NAC. R & M. Water pressure on tb~ hull was”measured during landings and take-offs at dltferent gross weights ati at abnormsl landings “at . Joseph P. ~anding Impact of Seaplsnes~ Pabst.Co. The Glenn L.. NACA TM NO. E. 226. No. 1937. Jones. Murphy.. (Moscow]. l(!h. g. 1928. A.. C. -. Teclmtka Vosdushnogo I?lota (Moscow).—--— . no. 10. 1929. No. 643. X. Ruth L.: her den Landestoss von Flugzeugschw’lmmern. 233. 3!+6. No.: On the Impaot of a Solid Body on the Surface of an Incompressible I&quid. L. Jshrb. . the ?iotlonof a F.. I 329 . April 19~3. John. [Av~la~~l ~ British Air Ministry Translation No. .._ ----. . Rep.-—. . with Vortex Separation. 236. ---—.: Water Pressure Distribution on a Flying Boat Hull.: Outline of the Theory of’Impact In the Landing of a Seaplane.: On the Theory of IfhsteadyPlaning and 232.-Amhlv.A.1930. R. pp. 1785. 229. Abel. Rep.. 1-13.-. Engr. May 1943. 1939. pp. C. Measurements of the magnitude and distribution of aooelerati. and Irwin. Ing.onsand stresses on the PB&3 airplane under boti normal and critical conditions. 290. ?fartlnCo. Sydow~ J. The Glenn L. Sedov. Smith.. . L. 1938 der deutsohen Luftfshrtforschung. . . Feb. 235. Taub.. .I 336.. --..NfLCA*LCRNO %23. pp. l?. No. 321. G. H/Res/161. Fate*Pressure Distribution on a Seaplane Float. 120-1~.: Model PM-3 .. Thompson.Measurement of Load Factors during Fllght and Water Maneuvers.. Sedovg L.L. . No. 234. oldenbourg (?tiich). and Morris. 230.I..-. . 1934. --. von K&&. . Thompson. 23 ~. Maude A. Rep. 2310 Sedov. Murphy. NO. 1931. 19 T 0. .: b Hull Launohing Tank (msorlptlve ). Schmleden. Josef: had Assumptions for th Landing Impact of Seaplanes. l&7. l?AOATM NO. Trans. ----.. . liACATM No.:The Impact on Seaplane Floats during Landing. q ~ G28 79 IMPACT LOADS Parks.: ~ber den Einfluss von Federung umi ~elung auf den Landestoss. B& Heft 1. 9k2. NACA TN No... 1933. F.-. NAOA Rep.: 238.. W.H. ‘lheoretioal treatment. British Marine Aircraft Experimental Establishment. L. G. NACA Rep. F. . .. Aug. . pp. —. . ..Flfissigkeiten . — . . . 2@. Papers of DIst.. Phys.. -. —---- ---- - IMPACT LOADS 239. . . M. . . . .Vee-Tgpe Seaplane on Water with Reference to Elasticity.. Weinig. .und Gleitvc@nge an der Oberfltichevon. . . vol.. . . 2@. Wagner.. . 12. S.: . ...“ . 1930. 1936.=.:.’ .. &: .--2.-.“ -. 226.. . . .-~ E& 12. no. Watenabe. ~. .Z. . . . .-’L -..?4.. a-. . .“ . Heft ~.. Herbert: her Stoss. . 1931. .— - .. and Chem Res. . -— .. Herbert: Landing of Seaplanes. (TolcYo). ”. 622.a. NACA T!4No. ~ “ .“ .. The theory is extended to include elastic floats by introducing the oonoept of equlyalent rigid bottom to substitute for the actual elastio bottom. _u_.: Impaot of a.=”--- . . . i . . NACA TM No. Feb 20. . Soi.7 ------——-------. . . . 2~1.::. . Wagner.-: ?.: Resistance of Smpaot on Water Surfaoe. . .’. 193-215. .f. --. 810.. . . 1932. .--4- —-. Testing technique.. W. Coombes. Inc. John Wiley & Sons. Brittsh R. G. Ebert. . Cong. Mech! (Csmbridgs. R. 250. . L. A. 246.. June 1912 .. -- 81 ~*243. G. 1718. P. mly 1944.. E.and Johnston. pp. 63-66.C.. Brooke.. . L. 61. 513-519. and Perring. R. Feb. porpoising. 297. TN No.: Re$earoh in the R.---- q L5G28 EXPERIMENTAL PROCEDURES . Starr: A ~lneral Tank Test of a Model of the Hull of the British Sin spore IIC Flylng Boat. P. 1939. 4. 1936. interference effect (twin floats). .: The Use of Dynamically Similar Models for Determining the Porpoising Characteristics of Seaplanes. 1935. NACA RB. pp. Seaplane Tank.-. Kass. Scale effect. 247.E. H. 193E Testing technique.stub wings. no.: The Farn‘DorcughSeaplane Tanlk. No. Scale effect. App. Dpo 807-825.. No. and Truscott.S. k M.A.Ig! - NACA {iCRNO . March 1934. Testing technique. ventilation.E. Coonibes. XXXIX.mltsof ‘IWOF1 ing Boats and Their Tank Models. W. ZH-2 -011. L. Proo.~ Jr. skin frlctim.: A Comparison of the Porpolsing Id. Perring. Coombes.Correlatlon of Towing Basin and Full Scale Effeot of Step Ventilation on Landing Stabillty. John R. L. P. .. . 1938).:. vol. Dawson. John W. depth of water.. Aero 1472. Scale effect.. testing teohnique (RAE tank). 248. G.. ITACATN No. Boundary layer.. VI. Jour.A. q *2h9.. British A. Tank. Aircraft Engineering.E. Sept. L. 580. Fletoher. Coombes.: Some Preliminary Measurements of the Boundary Layer Conditions on Models in the R. PB2Y-3 . vol.. P:: Scale Zffect in Tank Tests of Sesplane Models.. landing stability.. buoyancy. resistance (results from two tanks compared). Fifth Inf. Consolidated Aircraft Corp. no.. P. 19t 3. 245. skin friction. Rep.R.A. Scale effect. longitudinal stability.A. L. Tanks (FME). pressure distribution. Scale effect. 255. Aircraft Engineering. Locke. L5G28 EXPERIHENTLL PROCEDURES H. Method or condensing resistance data. porpolsing.. P. and Bott. 3Kll. Garner. testing technique. VO1. angle of dead rise. Aug. bo~dary layer. Rudolph. NACA TM No. NACA ARR No. II. Comparison of Results of Tests of the Singapore lIc Model Hull in Five Tanks. resistance . Testing technique. 269. Jr.. 1930.scale effect.: The Hydrodynsmlos of Marine Aircraft. H. L. twin floats. pp. 826. and Coombes. Frlctlonal resistance. 1937. Sept. 676. R. 252. pp. W. 1785. Helen L. no. Mttchell. P. 1932. 253.. Paul: The Take-Off of Seaplanes. stub wings.. 110 no.— . . F. J. 1930. 1 . 1930. vol. 18.: Tank Tests with Seaplane”Models. F. Lower.S. British A.C. stub-wing stabilizers. no. Spray. No.. spray strips. vol. 4B19. R. NACA TM No.Float Systems. S. 257. W . racing floats. MY 1933. 1937. 25& Schrb”der. methods of obtaining full-scale resistance. PP~ ~23-b3b~ Tanks (Vickers). 82 251.. testing technique. Schr6der. Jour. 20. 1943. Testing technique. Schmidt. tip floats. J. 1931. Jr. S.t Seaplane Hulls and Floats. W. mtt. Oct. 19.: Towing Tests of Models as an Aid In the ~esign of Seaplams. 19. R.: A mthod for Making Quantitative Studies of the Main Spray”Characteristics of Flying-Boat Hull Models. 193-196. & M. Jo P. 259. 255-259. 256. take-off.—— —. scale effect. NACAACR No. The Scale Effect In Towfng Tests titi Airplane .: General Resistance Tests on F1 lng-Boat Hull Models. Locke.R. h q 254. NACA Method of condensing ~ No. pp. 223-225. XXUPTII.no. Based on a New ~drodynamlo Reduction Theory. planing surfaces. NACA ARR KO. testing technique (DVL). resistance data. 621. II.and vol.(results from five tanks oompared). Aircraft Engineering. tab-off time. Method of calculating take-off.A. .Illllllllllillimli!llfllf 1 3 1176013542205 ~ . 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