effectsofwingnac00lang

8/4/2019 effectsofwingnac00lang

1/178

L-ll^l /ARE No. L5J05

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

WARTIME REPORTORIGINALLY ISSUEDDecemter 19^5 asAdvance Eestrlcted Eeport L5J05

EFFECTS OF WIKG AHD HACELLE MODIFICATIOHS ONDRAG AND V^AKE CHARACTERISTICS OF A

BOMBER-TYPE AIRPLANE MODEiLBy Eobert H. Neely, Bichard W. Falrljaiiks,

and D. 1111am Conner

Langley Memorial Aeronautical LaboratoryLangley Field, Ta.

NACAWASHINGTON

NACA WARTIME REPORTS are reprints of papers originally issued to provide rapid distribution ofadvance research results to an authorized group requiring them for the war effort. They were pre-viously held under a security status but are now unclassified. Some of these reports were not tech-nically edited. All have been reproduced without change in order to expedite general distribution.

DOCUMENTS DEPARTMENT


2/178

Digitized by the Internet Arcliivein 2011 witli funding from

University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation

http://www.archive.org/details/effectsofwingnacOOIang


3/178

^n-34^3^1^^^

NACA ARR No. L5J05 RESTRICTEDNATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

ADVANCE RESTRICTED REPORT

EFFECTS OF WING AND NACELLE MODIFICATIONS ONDRAG AND WAPS CflARACTERISTICS OF A

BOMBER-TYPE :,IRPLa]\IE MODELBy Robert H. Neely, Richard W. Fairbanksand D. Villliam Conner

S IT M M A R Y

An investigation of a model of a large four-enginebomber was conancted in the Langley 19-foot pressuretunnel to determine the effects of several wing andnacelle inodJ.f ications on drag characteristics and air-flow characteristics at the tail. Leading-edge gloves,trailing-edge extensions, and modified nacelle afterbodieswere tested Individually and In combination. The effectsof the various modifications were determined by forcetests, tuft observations, and turbulence surveys in theregion of the tail. Tests were made vi/ith fixed, andnatural transition on the v;ing and v/ith propellers oper-ating and nro-oellers off. Most of the tests were con-ducted at a Reynolds nuinber of approximately 2.6 x 10.

The results indicated that application of certainof the modifications provided worth-while improvementsin the characteristics of the model. The flow over thewing and flaps was improved, the drag was reduced, andthe turbulence in the region of the tail was reduced.

Trailing-edge extensions were the most effectiveIndividual modification in improving the flovv over thevJing with wing flaps neutral, cowl and Intercooler flapsclosed. Modified nacelle afterbodies were the mosteffective individual modification in reducing drag witheither fixed or natijral transition on the wing; ho'wever,trailing-edge extensions were slightly more effectivev;ith fixed transition. Combinations of either leadlng-or trailing-edge extensions and modified afterbodies weremore effective than either modification alone. With cowland intercooler flaps open, trailing-edge extensions withmodified afterbodies provided substantial improvement in

RESTRICTED


4/178

T.r; TfH

flov; and drag characteristics. V^'ith wing flaps deflected,enclosing the flap 'behind the inboard nacelle within anextended afterhody or cutting the flaps at the nacelleappeared to be the ir.ost promising methods of iiiiprovingthe flov/ over the flaps and the tail. Although theresults of hot-v'ire-anemorr.eter surveys were not conclusivein rer,rd to buffeting characteristics, the modificationsdid reo.i.ice the turbvilence at the tall with v;ring flapsboth nevLT:ral and deflected. The modifications, as a rule,were favorable to maxirnura lift. Appreciable reductionsin longitudinal stability of the ^aodel -.vere caused byaddition of leading-edge gloves and tr ailing-edgeextensions

INTRODUCTIONSeparation of flow over a wing increases the dragand has, in a number of instances, caused tail buffetingbecause of the irregular nature of the flow at the tail.Several wing and nacelle rncdifications, designed v;ith a

viev; to improving the flov; over tho vving, \;ere tested on amodel of a large four- -engine bomber to determine theeffects on drag characteristics and air-flo.v character-istics at the tail. Leadin,--edge gloves, wing trailing-edge extensions, and modified nacelle afterbodies v/eretested. The characteristics of the basic and m.odifiedmodel were determined by tuft observations, force meas-urements, and meas-jrements of turbulence and djTiaraicpressure in the vicinity of the tail. Turbulence v.-asmeasured by means of a hot-wire anemometer. The hot -wireanemometer equipment was furnished by the CaliforniaInstitute of Technology and was operated under the direc-tion of Dr. Kans VJ . Liepmann of its staff. The investiga-tion v/as conducted in the Langley 19-foot pressure tunnel.

S y M B L S

The coefficients and symbols used herein are definedas follovvs;C-j^ gross lift coefficient (L/qS)AC-r increment of m.aximura lift coefficient-miax


5/178

MCA ARR No. L5JO5 3Ct> drag coefficient corrected for jet-boundaryinterference (D/qS)Cj^ gross pitching-moment coefficient (M/qS'c)C-rj^ induced-drag coefficient [C^ /rrA]C-Q parasite-drag coefficient fCj\ - G-q.\AG-n increment of uarasite-drag coefficientPT(, thrust disk-loading coefficient for one

propeller ^Tg/pV^D^j

Vv root-mean-square value of the deviations, per-pendicular to v/ind axis, of instantaneouslocal velocity from its mean valueU mean value of instantaneous local velocity

along v;ind axisq. local dynairiic pressijre at tall

^ 1 ?\q free-stream dynamic pressure ( jpV ja angle of attack of wing corrected for jet-boundary interference5^ wing-flap deflection m.easured from neutral flappositionR Reynolds num'ber (pVc'/^,)whereL liftD dj:'ag; propeller diameterM pitching moment about center of gravityTq effective thrust of one propellerS wing area (22.219 sq ft)


6/178

i|. NACA ARR No. L5J05

c" mean aerodynamic chord (l.[p'4ii. ft)

A geometric aspect ratio ( = 12.8 )b wing span (16.875 f t ) 'V velocity in free streamp mass density of air^ coefficient of viscosity

MODELThe general arrangement of the model is shown infigures 1 and 2. The model was of wood and metal con-struction and was finished with lacqiier. Pertinentdimensions are given in table I.The v.'ing had Davis airfoil sections, 22.9 percentthick at the root and 9*3 percent thick at the tip. Themaximum camber was approximately 3 .k percent of the chordat the root section and l,k- percent at the tip. Thelocation of the maximum camber was constant across thespan at 3i'5 percent of the local chord. The geometricaspect ratio of the wing was 12.8 and the taper ratiowas 3.077;1.The horizontal tall had no movable elevator. Thevertical tall was off dijiring all the tests.The installation of the cowl flaps and intercoolerexit flaps is shown in figure 5 for their deflected posi-tions. The cov/1 flaps extended from the top of thecowling to a point slightly below the nacelle center line,The intercooler cooling-air exits were located on theupper surface of the wing.

STAIIDARD COKFIGURATION

The standard nacelle afterbodies (afterbody 1) areshovm in figures 3 and I4. with wing flaps neutral. Nopart of the nacelle afterbody is on the upper surface of


7/178

MCA AER No. L5JO5 5the '.Ing near the trailing edge. The extreme end of thestandard afterhodies was attached to the lov\/er siirfaceof the wing flaps and deflected with the flaps, as shownin figure 5. The wing flaps were of the Fowler type andconsisted of inhoard and outboard sections. Ordinatesfor the inboard section are given in table II. At theinboard nacelle, the nose of the flap was 2.14. percentv/ing chord ahead of and 2.9 percent wing chord below thetrailing edge of the wing.

MODIFICATIONS

In an attempt to delay separation of air flov; onthe wing in the cruise condition, the original Y\ring chordwas extended in order to reduce the peak pressiares andadverse pressure gradients. Leading-edge gloves (figs. 6and 7) were built to NACA ok-series ordinates modified tofair into the original Davis airfoil section. The glovesextended the v/ing chord 10 percent between the fuselageand the inboard nacelle and tapered to the originalleading edge at the outboard nacelle. Because thesegloves were added to the original wing, a perfect contourcould not be formed where the gloves faired into the vifing.

The trailing-edge extension was a thin metal stripattached to the flaps and deflected down 11 from thelower surface of the flaps. The extensions were deflecteddown 1 to 2 from the wing chord lines. The Installationof the extensions is shown in figure 7 Extensions oftwo different spans and three different chords v/ere tested.Extensions attached only to the inboard flaps are desig-nated 0.5 span, aiid extensions attached to both inboardand outboard flaps are designated 0.6 span. The chordsv.'ere 1, 2y-, and 3 inches. Unless otherwise specified,

' 1the term "trailing-edge extensions" designates the 1-inch-chord extensions attached to both the inboard and outboardflaps

The installation of the various modified nacelleafterbodies with wing flaps neutral. is illustrated infigures 8 to 10. Drawings of the modified nacelle after-bodies are given in fig-ures 11 to IJ . Afterbodies 2and 5j shown in figure 8, wer'e attached to the inboardnacelles only and differed mainly from the standardafterbody in that they had a fairing on the upper surface


8/178

MCA ARR IIo. L5J05of the v;ing. Aftarbody 14- ( fi"S . 9 ^^^'^ 12} vvas a beaver-tail afterbody Vv'ith a sma].l fa:'rlng on the upper s-^jrfaceof the wing. Afterbody ^, shown in figures 10 and IJ,was faired on the upper siu:'face of the wing forward tothe intercooler air exit. The lowei^ part was extendedin order to obtain a better afterbody shape.

The installatior. of the deflected flaps v;ith inboardnacelle afterbodies k and 5 -S shown in figures 1I4.and 15, respectively. With afterbodies if, tests v/eremade with the flaps cut out below the afterbody as shownin figure llj. and also -.vith the flaps not cut and extendingbelow the afterbody. Inboard afterbodies 5 enveloped thecenter part of the deflected flaps, and the flap-nacellej''jncture was faired with plasticine as shown in figure 15The tips of the modified afterbodies did not deflect withthe flaps.

A double slotted, or vaned, flap (fig. 16) v;astested in an attempt to improve the air flow over theflap. The outside contour and the installation of theflap and vane combination were the same as for theoriginal Fowler flap. The ordinates for the doubleslotted flap are given in table II.

APPARATUS AMD TESTSTests of the model v;ere made for two basic conditions:

(1) Cruise condition - wing flaps neutral,cowl and intercooler flaps closed(2) Landing condition - wing flaps deflected i|C,landing gear down, cowl and intercoolerflaps closed

For the cruise condition, a fev^' tests were also made todeterm.ine characteristics v^ith cowl and intercooler flapsopen.For the cruise condition, tests were made v.'ith themodel in the standard configuration and with leading-edgegloves, traillng-edge e-:tensions, and modified nacelleafterbodies. For the landing condition, tests were madewith the model in the standard configuration and withmodified inboard afterbodies and modified inboard fla^s.


9/178

MCA ARR No. L5JO5The cov/l flaps in the open position v^ere deflected 10.

'A'hen the intercooler flaps v/ere opened, the exit gap wasincreased 7/1^ inch, which corresponds to the maxiraumdeflection of the intercooler flaps. The air flow throughthe nacelle was adjiisted, with the model at an angle ofattack of 5*^, to provide a pressiore drop of approxi-mately 0.750. throu^gh the cowling with cov;l flaps openand a pressure drop of approxlriately 0.671 through theintercooler ducts with exit flaps closed.For a flap deflection of 1^0, the raain landing gearwas down; however, no provision v\/as made for siraulating

open landing-gear doors. For flap deflections of 0and 10, the landing gear viras removed. Host of the testswere made with the horizontal tail off. The vertical

Power conditions were simulated by matching thethrust coefficients of the model and airplane at eachlift coefficient. The variation of thrust coefficientwith lift coefficient for sea-level power conditions ispresented in flgivre I7. The thrust coefficients for 0.1].normal rated power at sea level correspond closely tothose for cruising power (0.6 normal rated power) at25,000 feet. The propeller blade, angle at 0.75 radiuswas 30.

It was believed that transition from laminar to tur-bulent flow on the airplane v/ing would occur at approxi-mately the location of the front spar. In an attempt tomake the results of the model tests more representative offlight conditions, most of the tests were made v/ith thetransition fixed at a chordv^ise station corresponding tothe spar location. The transition vcas fixed by placinga strip of 60-grain carborundum on the upper and lowersurfaces at the 10-percent-chord station of the originalwing section. The width of the strip between the fuse-lage and the outboard nacelles viras ' approximately 3/8 inchand tapered to approxlmiately 1/lj. inch at the tips.

The character of the flow over the wing and thenacelle afterbodies was determined by observing thebehavior of tufts, v;hich were attached to both the upperand lower surfaces of the wing and nacelle afterbodies.No tufts were placed ahead of the 20-percent-chord sta-tion of the wing. These tests were generally made m'ithfixed transition and with propellers operating atO.Ij. normal rated power; however, a fev/ tests were madev/ith natioral transition and with propellers off.


10/178

8 NACA ARR No. L5J05

Force and moment charactsristlcs were measured by asix-component automatically recording "balance system.Lift and drag were measured for all configurations. Theeffects of leading-edge gloves and trailing-edge exten-sions on the longitudinal stability characteristics weredetermined with the horizontal tail on (elevator neutral)for several power conditions.

Measurements of the air-stream turbulence were madeat several spanwise stations along the elevator hingeline by means of a hot-wire anemometer. The basic prin-ciples of operation of this instrument are described inreference 1. The turbulence measurements v;ere supple-m.ented by measurem-ents of the local d;^Tiamlc pressures atthe tail obtained from surveys with a rake of six pitot-static tubes. All surveys were made with fixed transitionand with the propellers operating at C.Ij. normal ratedpower

All tests were made with the air in the tunnel com-pressed to an absolute pressia'^e of approximately 55 poundsper square inch (p z. O.OO558 slug/cu ft). Most of thetests were made at a Reynolds number of approxi-mately 2.6 X 10 and a Mach number of 0.12; however, .afew tests were made at a Reynolds number of 3 -9 ^ 10,and a I'ach number of O.18.

RESULTS AND DISCUSSIONThe results of the investigation are discussed fromthe standpoint of (1) flow over the wing and flap,

(2) flow at the tall, (5) drag and lift, and (i^) longi-tudinal stability. The characteristics of the standardmodel and the effect of the various m.odifIcations areshovv'n for the cruise and landing conditions.

Jet-boundary corrections have been added to theangle of attack, drag coefficient, and the vertical posi-tion of the survey points with respect to the elevatorhinge line as follov/s:Aa = O.bSi^CL

acq = 0.01060^2A2 = -0.13c,


11/178

MCA /uRR Ho. L5J05whers Aa is in degrees, Az is in inches, and z isthe vertical position of the siJX'vey points v;ith respectto the elevator hinge line. No corrections have beenapplied to the data for the effects of model -support tareand interference or for air-stream misalinement

FLaV CHARACTERISTICS AT THE WING

The results of tuft observations that show the char-acter of the flo"/ over the vv'ing, flaps, and nacelles aregiven.

Cruise ConditionThe stall progressions of the model in the originaland modified configurations with vving flaps neutral aregiven in figures lo to 22 for cov/1 and inter cooler flapsclosed. The values of lift coefficient at vhlch separa-tion first occurred on the_ wing are given in table III.Diagrams shoving the flow over the wing at a lift coeffi-

cient of approximately O.S are presented in figure 23.Stall progressions for the model with cov/l and intercoolerflaps open are given in figure 2[l. The propellers v/ereoperating at O.Ii normal rated pov/er and the transitionYJ'as fixed at 10 percent wing chord except for tv/o testsof the standard modeic Diagrams are presented to showthe effect of power and the effect of removing the transi-tion strip en the -wing.

Standard configuration. - With co\?l and intercoolerflaps clobed, prop-.lici"3. operating at O.k normal ratedpower, and transition fixed, the initial stall on thewing occurred at a lift coefficient of about 0,63 v/iththe model in the standard ox" original conf igix;''ation(fig, 18(a)). The ir.ii-'xal separation occur?'ed on therear part of the v;ing to the left of each nacelle. Theflow over the wing directly behind each nacelle was roughbut not separated for most angles of attack, Withnatural transition (fig. l8(b)) the stall patterns wereabout the same as vjith fixed transition but the initialseparation occiorred at a lift coefficient of about O.9I.With propellers off and transition fixed, the initialseparation occurred at about the same lift coefficientas with the propellers operating, but at- higher liftcoefficients the area directly behind the inboard nacelleswas stalled (fig. l8(c)).


12/178

10 MCA ARR No.. L5J05Separated flow like that liiclicated In fig-ore l8produces an increase In drag and cculd cause buffeting.

The purpose of the modifications was to delay this sepa-ration and to cause a general improvement in ilow throughthe cruising range (Cj - 0.6 to O.9). A substantialimprovement in flow over the wing was obtained, as shownin figure 25(a), by deflecting the wing flaps 10. Thedrag, hov/ever, was increased.

Chord extensions.- Chord extensions delayed theinitial separation and improved the flow over the wingat higher lift coefficients.

Leading-edge gloves (fig. 19(a)) delayed the initialseparation to a lift coefficient 0.12 higher than for thestandard model. About the same improvement was realizedwith the l---inch-chord 0.3-span traillng-edge extensions.

. 2The O.D-span tralling-edge extensions were the mosteffective individual modification in improving the flowover the wing. The li-lnch-chord 0.6-span traillng-edge2extensions (fig. 19(c)) delayed the initial separationto a lift coefficient 0.21 higher than for the stanvdardmodel. More improvement resulted from the 2^inch-chord0.6-3pan extensions. Subsequent tests, however, weremade with the l^-inch-chord 0.6-span trailing-edge exten-sions because the greater improvement in flow with the2| inch extensions did not seem sufficient to v;arrantthe additional structural changes necessary to the air-plane. In evaluating the im.provement due to eitherleading-edge or trailing-edge extensions in terms of theincrease in lift coefficient at which separation firstoccurred on the wing, it should be noted that the gainin lift coefficient was partly due to added v;ing area.

Modified nacelle afterbodies.- Modified nacelleafterbodies caused only a slight delay in the initialseparation but im.proved the flow over the wing. Thisimprovement is shown for afterbodies 2 and 5 tiy comparingfigure 20 with figure l8(a) and for afterbodies hr and 5by com.paring figures 21(a), 21(b), 22(a), and 22(b) withfigures 19(a) and 19(c). Afterbodies I4. and 5 appear tobe most effective. No flow separation occurred on thelower surface of either the standard or modified nacelles,


13/178

MCA ARR No. L5oT05 11Com'b lnations of chord extensions and modified nacelle

afterbodies . - Chord extensions j, either leading edge ortrailing edge, in comhination with inodifled nacelleafterbodies were more effective in delaying separationand in improving the flow over the v/ing than were chordextensions or afterbodies alone. The combinations ofleading-edge gloves with afterbodies l\. and leading-edgegloves with afterbodies 5 (figs. 21(a) and 22(a)) delayedthe initial separation to a lift coefficient approxi-mately 0.16 higher than for the standard model. Wlthtr ailing-edge extensions in combination with eitherafterbodies 1; or 5 (figs. 21(b) and 22(b)), the Initialseparation occurred at a lift coefficient of about 0,91,which is approximately 0.2& higher than for the standardmodel. xiS shown in figure 21(c), a greater improvementin flow jas obtained with a combination of leading-edgegloves, traillng-edge extensions, and afterbodies l\..Separation on the inner v/lng sections was delayed to alift coefficient of over 1.0. A similar combination withafterbodies S vi/as only slls;htl^ more effective than thecombination of traillng-edge extensions with afterbodies 5-

Cow l and Intercooler flaps open .- With the model inthe standard configuration, opening the cov/1 and inter-cooler flaps caused separation of the flow over the wingdirectly behind them, at all lift coefficients (fig. 2l|(a)).The addition of trailing-edge extensions reduced theextent of the stalled area, as shown in figure 2J4_(b).vVith afterbodies I; and traillng-edge extensions on themodel (fig. 2l,|_(c)), the Initial separation behind the openintercooler flaps v/as delayed until a lift coefficient ofabout 0.55 had been reached. YHth Inboard afterbodies 5and trailing-edge extensions on the model, no separationoccurred behind the open intercooler flaps of the inboardnacelles (fig. 2i|(d) ) .

Landing ConditionStall characteristics of the standard and m.odifledmodel with wing flaps deflected are shown In figures 25to 27. For these configurations the propellers wereoperating at 0.i| normial rated power, the transition was

fixed, and the cowl and intercooler flaps v;ere closed.Standard configuration .- Vtfith the standard configu-ration and flaps deflected Ij.O (fig. 25(b)), the initialstall on the v/ing occurred ahead of the ailerons and was


14/178

12 NACA ARR No. L5J05

followed by separation bet^Tsen the nacelles. For allangles of attack and all flap deflections, separationoccurred on the part of the flaps blanketed by thenacelles. The flow over the lov^er surface of the nacelleand the part of the afterbody that deflected v/ith theflap was not separated. (See fig. 26(a).) Removing theafterbody tips from the standard model did not improvethe flow over the flaps. It Vi/as thought that separatedflow over the inboard flaps combined with Irregular flowcreated by the afterbody tips v;ould probably contributemost to any tail buffeting. Modifications for the landingcondition were therefore directed toward improving theair flow at the inboard nacelles.

Modifications .- ?\/ith double slotted inboard flapsdeflected 4OO (fig. 26(b)), the flow over the right flapwas not separated but the left flap was stalled, as wasthe standard flap. Prom tests made v;ith the afterbodytips removed and vfith power off, the separation over thedouble slotted Inboard flaps at 0.[|. normal rated powerappeared to be caused by the afterbody tip,v;hichdeflected with the flap, and the dissymmetry appeared tobe associated with the rotation of the slipstream. Whenthe standard flaps were continuous and were deflectedthrough afterbodies l\. (fig. 26(c)), the lower part ofthe afterbody and the surface of the flap belov; theafterbody were stalled at all angles of attack. Withthe flaps cut out at inboard afterbodies ij., as shov/n infigure li]., no stall occiirred on the flap or nacelle(fig. 26(d)). The same flow existed with trailing-edgeextensions on the flaps. Vi ith the standard flaps 1-deflected vrithin afterbodies 5 (fig. 26(e)), the flowover the flaps and afterbodies '.vas not separated at anyangle of attack. Adding trailing-edge extensions hadlittle effect on the flow if the extensions vifere cut outbelow the nacelles (fig. 26(f)).

The most promising methods of those investigatedfor improving the flow over the flap were enclosing theflap rear of the inboard nacelle -within afterbody 5 o^cutting the flap at the nacelle. Trailing-edge exten-sions and modified afterbodies, to a lesser extent,delayed separation on the inner wing panels and thusaggravated the tendency toward early tip stalling indi-cated by stall studies of the standard model. Thiseffect could be minimized by reducing the wing-flapdeflection.


15/178

MCA ARR No. L5J05 13PL0;J CHARACTERISTICS AT THE TAIL

The results of ttirbulence surveys at the tall arepresented in figures 28 to Jl for the standard model andfor several modifications . Diagrams showing the flowcharacteristics over the v/ing for conditions at whichsurveys were made are given in figure 32. The turbulencedata are presented as the variation of root-mean-squarevalue of the vertical velocity deviations with verticaldistance for several spanwise stations. Axial velocitydeviations v/ere of the same order of magnitude asvertical velocity deviations. Ivlajcimim. values of thevelocltv deviation are several times the root-mean-souarevalues. The vertical velocity deviations may be inter-preted as angle-of-attack changes; for example, a valueof V v'^/u of O.O4 is equivalent to a root-mean-squareangle deviation of slightly over 2^.

Buffeting tendencies are difficult to evaluatequantitatively because the root-mean-square deviationIndicates neither the large fluctuations that may occurnor the frequency. Both of these factors play an impor-tant role in determining buffeting characteristics. Themain value of the data presented is the indication ofthe effects of the modifications on the turbulent wake.The curves Indicate the normal wake of the wing andnacelles by an Increase of turbulence. Beyond this mainturbulent wake, there are small peaks that define theedge of the slipstream.

The variations of local dynamic pressure with ver-tical distance for the standard m.odel are Indicated infigures 55 to 35* The curves show increases in djmamicpressure due to the slipstream and depressions due towing or nacelle wake. The point at which the maximujndepression occurs has been assumed to be the center ofthe v;ake . The variations of wake-center position withlift coefficient are given in figures 56 and 37 ^o^ thestandard and modified models. Except for displacem_entthe modifications changed the profile of the dynamicpressure wake very littleThe vertical position of the peak values of tiu?bu-lence agree closely with the position of the dynamic-pressure wake centers. The vertical extent of the mainturbulent ?ifake is roughly the same as that for the


16/178

ll^ MCA ARR No. L5JO5dynainic -pressure wal^e . A comparison of the turbulenceand clynamic-pressi:re-su.rvey data indicates that only aslight amount of turbulence is produced by the slipstream;the greater part of the turbulence is prodiiced by thewake of the wins and nacelles.&

Cruise ConditionStandard conf igxaration .- ?or the standard model withcowl and intercooler flaps closed (fig. 28), the largestturbulent wake and the maximum turbulence occurred at

stations 15 inches rigbit and 27 inches left of the fuse-lage center line, which are behind stalled parts of thewing (fig. 52). The maximum value of '


17/178

MCA ARR Nc, L5J05 15turbulence whereas afterbodies 5 caused, little change.The downward displacement of the wake due to modifica-tions would be greater than shown in figure 28 if thedata were compared at the same lift coefficient. (Seefig. 56.)

Cowl and intercooler flaps open . - C ompar i s on offig-'jres 28 and 30 shows that opening the cowl and inter-cooler flaps caused large increases in the turbulence atthe tail both with the standard model and vvith after-bodies 5 ^T-^cl trailing-edge extensions. The magnitudeand extent of the velocity fluctuations were, however,much lower for the model with afterbodies 5 ^'^^ trailing-edge extensions.

Landing ConditionThe results of surveys for the landing condition aregiven in figure Jl for a spanwise station behind theinboard nacelle. V/ith both the standard and modified

models, the maxirn'oin value of \^ v Al occurred below theelevator hinge line.

With the flaps deflected within afterbodies 5j theturbulence was less than for the standard model, v/ithflaps continuous and deflected through afterbodies l\.,slightly greater turbulence was obtained than for thestandard m.odel. The increased turbulence was evidentlydue to the stall that occurred on the flap and lowerpart of the afterbody (fig. 26(c)). With the flaps cutout below the nacelle as shown in figure llj., the turbu-lence woi:!.ld probably be less than for the standard model.

DRAG Aim LIFT CHARACTERISTICS

The variations of the parasite-drag coefficient v>fithlift coefficient for the standard and m.odified model areshown in figui-'es 58 to i4-5 The lift, drag, and pltching-rrioment characteristics for the cruise and landing condi-tions are given in figures I4.6 to 52. Table III gives thenumerical values of the drag changes due to modificationsat several lift coefficients and the incremxents ofmaximum lift coefficients due to the m.odlfications


18/178

l6 NACA ARR No. L5J05

obtained, in the cruising condition. The data have notbeen corrected for support tares or air-stream irilsaline-ment and. therefore should not be considered, as absolutevalues nor should the shape of the curves be consideredcorrect. It is believed, hov/ever, that the changes In

g and lift due to modifications would not be materiallyected by the application of such corrections.draaff

Cruise ConditionInasmuch as flifht Reynolds numbers are much greaterthan that at -which the tests were conducted, the inter-pretation of the drag reductions due to the modifications

is difficult, particularly in the range where separationoccurs. The va.lue of drag reductions obtained at a givenlift coefficient of the model may not be in agreementv;ith reductions that would be obtained from tests of thefull-scale airplane. The results of the model tests,hoY^rever, are believed to be indicative of the resultsthat would be obtained from installation of the m.odifi-cations on the airplane.

Figure 58 presents the data obtained from runs madenear the beginning, middle, and end of the investigationwith fixed and natural transition. The displacement ofthe test points gives an indication of how closely testconditions (primarily model siorface condition) could beduplicated. Pa.xlng the transition at 10 percent vifingchord increased the drag ooefflcie?at at all values oflift coefficient and also decreased the lift coefficientat which the rapid increase in drag occurs.The effect of Reynolds n'omber on drag characteris-tics vifith transition fixed is shown in figure 39- J-'hedrag for each model configuration was lower at all lifts

at a Reynolds number of 3.9 x 10 than at a Reynoldsnumber of 2 . 6 x IQ ^ and the knee In the drag curvesoccurred at higher lifts wi':h the higher Reynolds nuinber

Chord extensions.- The effect of span and chord ofthe traillng-edge extensions in reducing drag is shown


19/178

IIACA ARR No. L5J05 17in figure l\.0. At a lift coefficient of O.7, reductionswith -O.J-span and 0.6-span extensions were approximatelyIn the ratio of 3'h-' The. 2f.- inch-chord extensions^ 1reduced the drag somewhat more than the 1-inch cxtensions. No further reduction was realized by increasing,the chord to 3 inches. Subsequent tests were made withthe 0.6-span 1- inch-chord trailing-edge. extensions

Changes in drag caused by trailing-edge extensionsand " leading-edge gloves were dependent upon the type oftransition. The 1--- inch -chord 0.6-span. tr ailing-edgeextensions reduced the drag coefficient of the modelby 0,0038 with tra.nsition fi::ed at a Ijft ccsfficLentof 0.7 (fig. I^lfa)). Yfith natural transition (fig. [|.l'(b)),the trailing-edge extensions increased the d'rag O0OOO3 ata lift coefficient of 0.7 but at lift coefficientsabove 0,8 appreciable reductions were obtained. Leading-edge gloves reduced the drag coefficient b;y 0,0028 at alift coefficient of 0.7 with fixed transition andby 0.0012 with natural transition (fig. I|-l ) . Because ofthe imperfect contour formed where the gloves faired intothe wing, the resuJ.ts obtained with the wing modified Inthis manner are probably not so good as v/ould be obtainedif the v;ing were built to the revised dimensions.^o

Modified nacelle afterbodies.- All modified inboardnacelle afterbodit :', reunced ihe drag of the model atcruising lifts (fig. I|-2 ) but had little effect at lowlifts. The order of increasing effectiveness was after-bodies 2, 3, Ij., and ^. Modified afterbodies on all fournacelles reduced the drag at all lift coefficients. Pourafterbodies ii reduced the drag coefficient of the modelby COOjIj. V'/ith fixed transition and O.OOI7 with naturaltransition at a lift coefficient of 0.7 (fig. 1+3). Fourafterbodies 5 (fig. kh) were somewhat less effective inredticlng the drag than four afterbodies I4.. Modifiednacelle afterbodies were the most effective individualmodifications in reducing drag when considering bothfixed and natural transition on the wing; however,trailing-edge extensions were slightly more effectivev\rith fixed transition.

Propellers-off stall studies of the standard model(fig. 18(g)) show that at a lift coefficient of about O.7


20/178

18 MCA ARR No. L5J05the flow behind the inboard nacelles was separated butthe flow behind the outboard nacelles was smooth. Thesestudies and a consideration of the shape of the dragcurves Indicate that the modified inboard afterbodiesreduce the drag by delaying separation on the wing,whereas the modified outboard afterbodies reduce the dragby Improving the afterbody form. This explanationprobably accounts for the differences between the effec-tiveness of the inboard and outboard afterbodymodifications

C onb inations of chord extensions and modified nacelleafterbodies .- The combination of chord extensions andmodified nacelle afterbodies generally was more effectivein reducing drag than either modification alone. Some ofthe more effective combinations with the drag-coefficientreductions at Or = 0,7 2.re as follows;

Modification Fixedtransition NaturaltransitionPour afterbodies h. and trai ling-edge extensions 0.00.^5 0.0015Pour afterbodies 5 ^-^'^ tralling-edge extensions 0.0053 0.0005Four afterbodies 5 ^^'^ leading-edge gloves O.OOI16 O.COI5Pour afterbodies 5* leading-edge

gloves, and trailing-edgeextensions O.OOiiS 0.0017

There appears to be no advantage in combining leading-edge gloves with afterbodies [j. for reducing drag.All modifications increased the maximum lift coeffi-cient of the model with either fixed or natural transi-tion, and most of the modifications Increased the slopeof the lift curve.Covifl and intercooler flaps open .- Y^'ith the model in

the standard configuration, opening the cov;l and


21/178

T'ACA ARR No. L5J05 19

Intercooler flaps caused a large increase in drag. (Com-pare figs, [i.5 azid 58.) The. resulting high drag coeffi-cient vras decreased O.OO72 at a lift coefficient of O.7by the addition of inhoard afterbodies 5 3-^d. trailing-edge extensions or four afterbodies Ij. and trailing-edgeextensions ffig. l-i-5 ) It should be noted that theseriodif ications reduced the drag coefficient approxi-mately C.OOl.i.O with cowl and intercooler flaps closed.

Landing ConditionThe lift characteristics for the standard and modi-fied models with wing flaps deflected h..0 are presentedin figure ^2. Vi'ith transition fixed and propellers off,the same maxim-um lift coefficient was obtained withdouble slotted inboard flaps or with standard flapsdeflected within afterbodies 5 ^-s was obtained v/ith themodel in the standard configuration.In order to eliminate flovi? separation that occurredon the flaps and the I'ear part of afterbodies li, part of

the inboard flaps \were cut away. This change resultedin a reduction of about 0.1 in the ma::imium lift coeffi-cient. An additional reduction would result if the out-board flaps were cut. With flaps deflected througheither afterbodies I4. or 5 ^^^ addition of trailing-edgeextensions increased the maximura lift coefficient byabout 0.2; the resulting lift coefficient was greater inboth cases than for the standard ro.odel.

LONCITiroiWAL STABILITY CHARACTERISTICSPitchlng-moment curves for the standard and modifiedmodel with propellers removed and horizontal tail off arepresented in figures l\.6 to '^'1, Power-on pitching-m.omentcurves with horizontal tail on and off are presented infigures 5? to 55' ^^ corrections have been applied tothe pitching moments but the results presented indicatethe effect of the various modifications. With tail on,the large differences in trimi and the fact that largeparts of the curves are considerably out of trim make anaccurate evaluation of stability changes difficult.Moment ciorves for several elevator or stabilizer settingswould be required.


22/178

20 NACA ARR IIo. L5JO5

As indicated by changes in the slopes of the pitching-norrent curves, leading-edge gloves and trailing-edgeextensions caused appreciable reductions in longitudinalstability.

Cruise ConditionViith v/ing flaps neutra" and the horizontal tail on

(fig, 53), the pitchir_g-?nonent curves shovi that the modelwith chox'd extensions and modified afteroodies was lessstable than the standard model for all pov/er conditions.Up to a lift coefficient of 0.6, the combination oftrailing-edge extensions and inboard afterbodies 5 changedthe noxnent- curve slope dCj-p/dCr, approximately 0,0l|.to 0.06 from the standard conflgura.tion. The com.binationof leading-edge glo'/es, trailing-edge extensions, __ andafterbodies 5 changed the slope approximately O.O8 to 0.10from the standard configuration. Above a lift coefficientof 0.6, the modifications were micre destabilising,probably because the delayed separation on the inner wingpanel resiilts in increased do'.vnv.'ash. A satisfactorycomDromise between the adverse stability changes and flowand drag Improvements due to trailing-edge extensionscould probably be obtained with an extension having asmaller chord thar. those tested.

Landing ConditionVJith wing flaps deflected, horizontal tail on, andpropellers operating at 0.1]. norm.al rated power (fig. 5VCb))jthe slops of the pitching-inoment curve was approxi-mately O.0I4. less negative (model less stable) with thecombination of trailing-edge extensions and afterbodies 5on the nodel. With leading-edge gloves, trailing-edgeextensions, and afterbodies 5 o'- the model, the slope ofthe moment curve Y;as O.O7 1-ss negative than with themodel i:.i the standard configuration. V/ith propellersoperatiiig at zero thrust (figo 5^(a)), only a slightchange in the slope of the moment curve was caused byeither modification. The adverse effects on stabilitycould be minimized by reducing the flap deflection.


23/178

NACA ARR llo. L5JO5 21

CONCLUSIONSProm an investigation of a model of a four-enginebomber -type airplane that was made to determine effects

of wing and nacelle modifications on drag and air flow atthe tail, the follov;ing results were shown;1. Vv'orth-while improvements in the characteristics

of the model were obtained v/lth certain modifications oThe im.provements vvere indicated on the basis of improvedflow over the wing and deflected flaps, reduced turbulencein the region of the tall, and reduced drag.

2. Tralling-edge extensions were the most effectiveindividual m.odificatlon in improving the flow over thewing with v/ing flaps neutral, cowl and intercooler flapsclosed. Modified nacelle afterbodies were the most effec-tive individual modification in reducing drag with eitherfixed or natural transition on the wing; however, tralling-edge extensions were slightly more effective with fixedtransition. Four afterbodies Ij. (a beaver-tail type) alonewere superior to four afterbodies 5 (^i^ extended conven-tional afterbody) alone in reducing drag. Combinationsof either leading- or tralling-edge extensions and modi-fied afterbodies were m.ore effective in delaying separa-tion and reducing the drag than either modification alone,

5. \iVith the model in the standard configuration,opening the cowl and Intercooler exit flaps caused sepa-ration on the vjlng behind the Intercooler air exit.Increased the drag considerably, and increased the tur-bulence at the tail. These conditions were greatlyimproved by adding modified nacelle afterbodies andtralling-edge extensions.

h.. lilth. wing flaps deflected, enclosing the flapbehind the inboard nacelle within nacelle afterbody 5 o^cutting the flaps at the nacelle appear to be the mostpromising methods of improving the flow over the flapsand reducing the tiorbulence at the tail.5. Although the results of turbulence surveys made

v\rlth a hot-wire anemometer do not indicate definitelythat buffeting v\/ould occur v;lth the standard model orthat the modifications would eliminate buffeting, themodifications did reduce the turbulence at the tail withwing flaps either neutral or deflected.


24/178

22 NACA ARR No. L5JO5

6. Appreciable reductions in the longitixdlnal sta-bility of the model were caused by leading-edge glovesand trailing-edge extensions. In the landing condition,chord extensions also aggravated the tendency towardearly tip stalling obtained with the standard model.7. All rriodificatlcns increased the ma:^linuin lift with

vving flaps neutral and gave a maJciKuxi lift equal to orgreater than that for the standard model with wing flapsdeflected except when the inboard flaps were cut outbelow afterbodies Ij..

Langley Memorial Aeronautical LaboratoryNational Advisory Committee for Aeronaiiti;Langley Field, Va.

REFERENCE1. Dryden, E. L., and Kuethe, A. LI.: The Measurementof Fluctuations of Air Soeed by the Hot -WireAnemometer. NACA Rep. No. 52 0, 92^.


25/178

MCA ARR No. L5J05 23TABLE I

GENERAL SPECIFICATIONS OF MODEL

Wing:Airfoil section DavisRoot-section thickness, percent . . 22.9Chord, ft 2,0Tip- section thickness, percent 9.5Chord, ft 0.650Taper ratio 5.077:1Span, ft 16.875Area, sq ft 22.219Aspect ratio 12.8Mean aerodynanic chord, ft 1 Jj)|)iCsnter-of-gravity location, percent M.A.C. . . 2iToAbove root chord, ft O.183Eehind leading edge of root chord, ft ... O.525Incidence (with respect to fuselagecenter line), deg 3.OGeometric tv;ist, deg . .p'uselage

Over-all length, ft 10. 386Taximum diameter, ft 1 . I87 Ma:cimiara frontal area, sq ft I.I07

NacellesT^rontal area (each), sq ft O.I1.5OIncidence (with respect to wing chord), deg . . -3.0

Horizontal tail:Area, sq ft 5.201Span, ft 5.375Incidence (v/ith respect to fuselagecenter line), deg -1.0Elevator hinge-line location (fuselagehorizontal)Horizontal distance rear of leading edge ofroot chord, ft "' 5.866Vertical distance below leading edge ofroot chord, ft O.05I

PropellersNuiiiher I4.Diameter, ft 2.082Blades , 1|.Blade design Curtiss Viiright 10l6-lb

NATIONAL ADVISORY COMIITTEE FOR AERONAUTICS


26/178

2ij. NACA ARR No. L5J05TARIE II

ORDIMTES FOR ?0Y;LER AI^ DOUBLE SLOTTED FLAPSl^tations and ordinates given in Inches and are meas-oredfrom leading edge and reference line of Fowler flap]

Foviler flap

Station

.078.is6

.512M9

.62s

.^571.2501.S752.5005.125.7504-.?755.0005.625b,25

Upper I Lcversurface ! sur-face0.196

M-

I

.652.688

.769.8IQ

. 8i(ii.821

.522

.366.220

.0i;0

0.196.078.062.01+3".oLk.o!i6. 03I1-.026.01I+.006

n

L.E. radius- O.125

NATIONAL -ADVISORYc o:,'n,:iTTEL for aeronautics

-1!

Double slotted flapVane

Station, i'^; 6.28.111.55. 1^1.031.26

Lov.rersiu?face0.06.12.30.1:6

.62Nose of flap

Station1.031.111.191.3-'i1.501.661.972.282.50

Uppersiu'^face0.20.38'H.56.78.82.82

Lovjersurface0.20.05.03


27/178

NACA ARR No. L5J05 25

OMHMgo -^^o om o o6 NOHe nKM T1g BoM I-)-< AM )H * iHH d H

rH 4 4s

% C Bg % g ^ * H H H t e^ a B at a a a n +> a 4J^ f> fl A u u c a C C C > > >

*> 4) ^ ^ cH t-i iH K K K I-i r-{ rH %1 Vi 4J nB a (Dd ^ 4J 'dft-H O> rH a> pa t. t,V O (DOB VhH a BJh e a H>d

a) t3 in43 > o cdB o ^ o43 tO(0 CB *>-H^ . B rHVh t, O BH O X! 4a

1-5 li. SCOBP o t3


28/178


29/178

NACA ARR No. L5J05 26

IMDEX TO FIGURESa. Illustrativ* Figures

Figure Material presented123k56I910

1112IS151617

Three-view drawing of modelModel mov:ated In test seeticmPhotograph, standard nacelle afterbodies, 6f = 0Drawing, standaM nacelle afterbodiesPhotograph, standard nacelle afterbodies, 6f - i+ODrawing, L.. glovesPhotograph, L.E. gloves and T.S. extensionsPhotograph, nacelle afterbodies 2 ail 3Photograph, nacelle afterbodies I4., Of = 0^Photograph, nacelle afterbodies 3, 6^=0^Drawing, nacelle afterbodies "pDrawing, nacelle afterbodies I4.Drawing, nacelle afterbodies 3Photograph, nacelle afterbodies I4., 6f = k.(fiPhotograph, nacelle afterbodies 5, 6f = I4.OOPhotograph, double slotted flapCalculated thrust coefficients for B-32 airplane

b. Stalling Characteristics; 0,14. JTormal Rated Powerj Transition Fixed

Figure Configuration 6f(deg) Cowl and Inter-cooler flaps18(a)

18(b)^l8(e)192021Z2232425(a)25(b)2627

Standard modelao-do-Chord extensionsModified Inboard afterbodiesBiboard afterbodies i|. and chordextensionsInboard afterbodies 3 ^^^ chordextensiona

Comparison of stall patterns at CjStandard and modified modelStandard model0.8

-do-Standard and modified model (flow overinboard afterbodies and flaps)Modified model (flow over wing)

n

10

Lo1^0

ClosedDo.Do.Do.Do.Do.Do.Do.OpenClosedDo.Do.Do.

^Natural transition,^Propellers off.

NATIONAL ADVISORYCOMMITTEE FOR AERONAUTICS


30/178


31/178

NACA ARR No. L5J05 27IHTEX to PIOTOES - concluded

o. Tall-Surve7 Dat*} 0.1^ Normal Rated Power; Transition FixedFigure Material presented Form of data (d?fii

Co*l and Inter-oooler flaps2829505152U.553637

standard and modified model, a = 7.6and 8.70Effect of angle of attaokStandard and modified model, a = 7.5Standard and modified model, a er do-- do- FixedT.E. extensions do -do Do.la Standard afterbodies with chord Fixed andextensions do do naturalI42 Effect of various nacelleafterbodies -do -do Fixed1^3 Afterbodies k with chord Fixed andextensions -do do- naturalkk Afterbodies 3 with chordextensions . .do do Do.k5 Effect of modifications withcowl and Intercooler flapsopen do (^n Fixedki Effect of transition Co. a, C

against Cj, Closed Fixed andnaturaln T.E. extensions do - . -...^.do- FixedStandard afterbodies with chord Fixed andextensions do do- naturalk9 Afterbodies k with chordextensions .^0 -do Do.50 Afterbodies 5 with chordextensions -do .do Do.51 Effect of modifications withcowl id intercooler flapsopen -do Open Fixed52 Effect of modifications on lift Cj^ against a Uo Closed DO.

e. Longitudinal Stability Characteristics; Transition Fixed

Figure Configuration 6f(deg) Cowl and inter-cooler flaps TallClosed Ctodo - -do-do -do-ko do Onko -do- -do-do Off1+0 -do -do-

Power53()53(1')55(c)54()514- (b)55(a)55 (t)

Standard and modified model-do--do-Standard and modified model

Standard and modified model

Tg =0.I4. normal rated powerNormal rated powerTq 0.I4. normal rated power0.4 normal rated power0.I4. normal rated power

NATIONAL ADVISORYCOUtlTTES FCfi ASRONAUTICS


32/178


33/178

NACA ARR No. L5J05 Fig. 1

NATIONAL ADVISORYCOMMITTEE FOD AEDONAUTICS

Figure I ~ Three-v/ew draw/ng of model.


34/178


35/178


cc


36/178


37/178


Figure 3.- Standard nacelles. Sf = O'


38/178


39/178

NACA ARR No. L5J05 Fig. 4a

f

I

I


40/178


41/178

NACA ARR No. L5J05 Fig. 4b

f^ V ^


42/178


43/178


Figure 5,- Standard nacelles. h^ = 40


44/178


45/178


S3 c

o oMS

5

oh o H os-ow t-oj voo\ojint-eoO5i t-'O'O'Oinin-'fto'o w*H * *

i! in r-i o^tfi ^^ cy * o o^ o\ cu OSay ow oj H c^co^-ô*no^r^ Rra CO< ssssssêssaas ~ a

1d

iil o\cy b-m'0'*3oo\ino w tog

11 O 'JrJ34Â^t^tZ^ Jft

. bs11

^ -* CJin H tQ Q (O -|- Op iftH nOOJ*Oj'lO-*Ot^COOHOJ* lOto'Hr-^r^Hr^

o tfMnoootoF-ojinOin5 o iHc\jvnt-OinOmOinHrJ CUCU(0(0

i

i

t


46/178


47/178


Figure 7.- Leading-edge gloves and trailing-edge extensions.


48/178


49/178

NACA ARR No. L5J05 Fig. 8ab

(a) Afterbody 2.

(b) Afterbody 3.Figure 8.- Inboard nacelle afterbodies 2 and 3.


50/178


51/178


NACALMAL S8I87

Figure 9.- Nacelle afterbody 4. Sf = O'


52/178


53/178


Figure 10.- Nacelle afterbody 5. = .


54/178


55/178



56/178


57/178



58/178


59/178


"o-."*-(V). ^oo- i^r\ - -^

^


60/178


61/178


o


62/178


63/178


^


64/178


65/178


Figure 14.- Inboard nacelle afterbody 4. Sj- = 40.


66/178


67/178


igure 15.- Inboard nacelle afterbody 5. Sf = 40 .Figu


68/178


69/178


^1^ QBBHBi^^__ - '^^^^B^m "*?,* , i- * *i(i*-T- XjMrii^ ^ ^9 "'^^H

mk 1L ' ^- 1^F N^C.A" LMAL 37 877Figure 16.- Double slotted inboard flap.


70/178


71/178


>

\

NATIONAL

ADVISORY

COMMITTEE

FOR

AERONAUTICS

111

1

i\

0.4

normal

rated

power

(800

hp)

11

1

1\

^ \

al

ra

00hp

Norm (20 V^X s. X\\, \\ \ .\\,\\\\

^M-

^- ^

G^f\j

QD

^

'O ^^ ^ S ^ c:^

COCo

Co

>0)

Ia

cHboC0)

0)Couo


72/178


73/178

NACA ARR No. L5J05 Fig. 18a-c

^Cb

Q . Cl

aXc: (0O t-,4-> ,-HCO t.

O oj

t-.E-"

(d?< oPJ ono ooo

(D

Osom(Dr*X)

to-p

I

CO

(D

OoT)^H nHi dfl .01 -o+^ (DCO ffiO

IDP,a>

(D.-IOOOUO

Ph


74/178


75/178

NACA ARR No. L5J05 Fig. 19a-d

^ s ^D C * ^h O

/././

s"^cx ^ "*

d (0 t\j (>M ^ ~vi

i) ^^O (O Og QO > Qiicvj "^ *-;

Dl^

~c :* (*\ N^^ * "^^-QO N

T)u CDhOfl 0IDa bOaC -^l^g

aaj0}I

auooao

09o01c:

:

(0CD^ /~i rHo C\2m

^~ Ii-"i>^\ ^ d TdW > ^- e J3 o^-^F3e i +3 CD1

H5 O*y s CD


78/178


79/178


"'i's ^^^O (0 t\i "O > Cit\i -"^ -^

D //./ ?t""v

''^^Q HCQ a

.-0) 5?^ \ t a itH mFi "^^ cd(D Cd fl +5\ "^ ^ -> o tH' 1 5)- ^.^ lH (Dt| u o CO r;

- S H oS ,-1oo <


80/178


81/178


L iS "=->^O to Rj a.^o-''"v "=^^

-O (O t\, P Mr a>bO

0)a> U)60 -aO (D?* 4>

a ^cd cd


82/178


83/178


^^^^^N

STALLED UNSTAaED

INTERMIT- DIRECTIONTENT5TALL OF FLOW \

Tfa/lfng-a:^ ex^ns/ons

fXough

cc = 1.5'G =Q ^

Kough- 6.5

Afferbod/ss4;Jead/ng'-\edge gloi^es;i7tri//ng-

a =0 80:;' i\ ~~'":i ^^ ejdens/ons cc -6.5Cl =0.7S C. -0--Afferbod/es5; lead/ng-edge g/oi^ss -Mydz/ig-~^~^edge &dens/o/7S

NATIONAL ADVISORYCOMMITTEE FOR AEDONAUTICS

Figure 23. -Comparison of ^fa// patterns with standard and modifiedmodzl at a //ft ooeff/c/e/7f of approx/mcde/y OS. (Sf>=0 ; ca^/ andintercoo/er f/aps c/o.sec/j 0^4 norma/ rated power; tror7s/t/on f/xedR^Z,6O0,O00.


84/178


85/178


=S^i k_- r*. x.T!^. *t ""--t^o '^'^Ci (o c\j\j -^ -< * > o

yA/

N r^'

O Ql\i -< --^

^ -^//y, 6 505 Y,,>,,,\ o>

a QN

o to t\j Qt\i -~< -^^ ^

:5iEQ lo (DT-l PO T) fitJ W)(J c on1

03r; tJ O*H o ad on m -H o^ tn rn

a) 4-5 a .-1 .>o o r~i^ H 4-> oKH cd n1 a) (rtn-J U f


86/178


87/178

NACA ARR No. L5J05 Fig. 25a,

//.A

ooot3 ^a o o &r / ' ,-1 OJ'" J*=


88/178


89/178

NACA ARR No. L5J05 Fig. 26a-f

'O

Di|5

^

on) '-I

* Ci

*-, o< o

ooQ

aoE .oa 'Ou aj ^3nj IJCO d

1 4J ^^ OC P (D oo +J oH 4-> C! .hO) 3 rH oCh o

0) c .1 i(T3OJ3 o Ku

OJ60 II o*-l a .^ (D- < 40 +JOEOVi -rHtng i . c!< a= CO a)o -J


90/178


91/178


^s,"=3;

O to c\j Ct)rr; C\i Og ^

// 1^

L'^a. 5;~.Ci ^ c\j >^^i:(0 ^ ^ ^ ^ ^C\i INj C\i ~;

^.S/oyy

flap continuous.a = 12.7; C^ = 2.51.

Distance left of fuselage center line^1^ D

(In.17 )

I&& 2023

k^ h(c) Inboard afterbodies 5.a = 12.7'^} Cl = 2.55.

(d) Leading-edge gloves.Inboard afterbodies 5>and tralllng-edgeextensions, a = 12.9 JCl = 2.95.

o 02 .04- O .02 .aa\/7/u NATIONAL ADVISORYCOMMITTEE FOR AERONAUTICSFigure 51.- Vertical velocity deviations in region of horizontal

tall for standard and modified models. 5|< = i;0; cowl andintercDoler flaps closed; transition fixed; O.i; normal ratedpower; R a; 2,600,000.


102/178


103/178

NACA ARR No. L5J05 Fig. 32a,

STALLED UNSTAUED

INTERMIT-TENT 5TALL

DIRECTIONOF FlDW

Cl = 0.43 'y-^'^

Rough

Rough

RoughCoiv/ flap: open 10Iniercoo/er //a/s cpen

Rough

Cl = 0.Q9 CRough

Con/ flaps


104/178


105/178

NACA ARR No. L5J05 Fig. 32c,

STALLED UN5TALLED

^^X^:;^ INTERMIT---^ssi^v TENT STALL0. V\


106/178


107/178


00^4.3"

%I

05 ooh ^v(

f

.3 1.0 l.Z

oc=/0. 7

I-^

h.w13 In. from fuielage center line

LeftRl^t1Q-

n^Ox.f ^p

^

^ ^ 1's

^^}

rQ"'^'

20 In. frcB fuselage center line

1 ^rr pc. R(^ V

\Ti BS9A?,^

c

\ %\, . %}

{

( )

.^

27 In. from fueelage center line.8 1.0 12 U.6 1.0 1.2 14

^*/9

oc=l2. 7 "

-^z_

i[^\k1P ^i ^ 0- jj

n\ ^h

< )ck'

.8 AO i.a laNATIONAL ADVISORY

COMMITTEE FM AERONAUTICS

Figure iJ.- Dynamic -pre 8 sure variation in the region of the horizontal tail.Standard configuration; 6^. = 0; cowl and interoooler flaps closed; transltiafixed; 0.1). normal rated power; R K 2,600,000.


108/178


109/178


30PO^

I

^*^ .6

(ji cc-4.3u


126/178


127/178


(/>u> t-ifLAD

OftA{

I

< "^Z UJ1 1- t- _______^~- ^^___ ' i z

GP~-^ /^ < Z X8.^ / / ^t]ia o 1o H JP nn C *JOS D 4J lla ,^ KhO M(7)11 U60O inID f>

m oC D. Co oH T3 -h+j CD +Jcd -^^ -Ho cd COH tJ C

ti-i td.H rH IjO EE S-i -o Vjo o

co

O O -HCD td(^ +J +Jtn IdW rHbo cdI C *J. -H Cm -p oin (d N


174/178


175/178


o ^ 00 (O

st

^.


176/178


177/178


178/178

UNIVERSITY OF FLORIDA

3 1262 07762 833 6 ^rUNIVERSITY OF FLORIDADOCUMENTS DEPARTMENT120 MARSTON SCIENCE UBRARYP.O. BOX 117011GAINESVILLE. FL 32611-7011 USA

^

effectsofwingnac00lang

Documents