.
“-
I
-1
NATIONALADVISORY COMMITTEEF(JR AERONAUTICS
.TECHNICAL NOTE
,.●
No. 1239
pJR21194’f-i
WIND-TUNNEL INVESTIGATION OF *E EFFECT OF POWER AND F@l?f
ON THE STATIC LONGITUDINAL STABILI~ CHARACTERISTICS
OF A SINGLE -ENGINE LOW-WING AIRJ?WUNE! MODEL
By Arthur R. Wallace, Petev F. Rossi,and Evalyn G. Wells
Langley Memorial Aeronautical LaboratoryLangley IHeld, Va. .
f
,
.
. . . ... .
Washington
April 1947
“i t .-
. . ..
- .*-.
f
. .
.
I!lrj!llll[lll!llll[llllilllllll● ..a ._.> ‘ 31176014333455___— — -—..
NATIONAL ADVISORY COMW2T?EE FOR AERONAUTICS
TECHNICAL NOTE NO. 1239
WIND-TUNNEL INVESTIGATION OF TEE EFI!ECTOF POWER AND FLAPS
ON THE STATIC LONGITUDINAL STKBILITY CHARACTERISTICS
OF A SINGLE-ENGINE LOW-WING ASRPLANE MODEL
By Arthur R.and
Wallace, Peter F. Rossi j
Evalyn G. Wells
As part of a comprehensive investigation of the effect ofpower, flaps, and wing position on static stability, tests were.made in the Langley 7- by 10-foot tunnel to determine the loi@i-tudinal sbbility characteristics with and without power of atypical low-wing, single-erigineairplane model with flaps neutral,with a full-span single slotted flap, and with a full-s~ dotible “slotted flap. The horizontal tail incorporated a leading-edgeslot for the flap-deflected conditions and was placed high toavoid the slipstream. Som data are presented for the isolatedhorizontal tail. With the double slottid flap deflected som,air-flow surveys were made in the region of the tail and thewing st&l.1was studied by means of tufts. .
With flaps deflected, lfft incremmts were increased by 0.16for the slngl.eslotted flap and 0.42 for the double slotted flapwhen power was applied. Power also increases the slope of theuntrimed lift curves (increase of O.osk for the double-slotted-flap condition).
Deflecting the flaps increased longitudinal stability slightly.The windmilling yropel.lershifted the neutral point forward from 1 to5 percent mean aerodynamic chord. The effect of power on longi-tudinal stability was small except for an erratic effect with thesingle slotted flap and at very high lift coefficients with thedouble slot~bd flap. The success in obtaining power-on stabilitywith the double slottid flap was attributed to the fact that thetail was out of the slipstream. The stabilizer nose slot impromdthe stability emd delayed the tail stall but reduced the elevatoreffectiveness. Sufficient control was provided by the tail astes~d. In order to avoid possible tail st&Ll, however, tie flapsshould le deflected S1OWQ. A larger tall volti would be deEirableto provide the necessary tail loads encountered at more forwardcenter-of-gravity locations.
*X= .—
. -i
,-. . ..
.
—
—
..__ .-
—
—
.
,*,.
lNTRODUCTI@
e NACA TN No. I-239
..
With the develcqyent of higher-powered airplane engines, theeffects of power on airplane stabili~ have beccme of’considerableimportance. The propeller itself has an appreciable effect-mairplane stability even when it is In the wirdmtlling conditionoWhen power is ayplied, the effect of the propeller is much greater.The effect of power cm airplane stability may be divided Into-twoparts: firstj the direct effects of the propeller - that 3s,thrust, torque, normal force, emd so forti -that act on the airplanethrough the propeller shaft; and second, the effecte of tie sMP -stream on the other parts of the airplane. Some of the effects ofpower are shown in references 1 end 2.
Another trend in aeronautical progress is the development ofbetter high-llft devicee to tiprove performance. Recent work haashown that.satisfactory lateral-control devices can be developedfor full--span.flaps, which meka the widespread use of’such flaysprobable. Flaps are known to increase the difficulty of [email protected] trim and stability for all flight ccmtitions and toticrease the adverse effects of’power in many cases. The Use ofhi@er-lift- flaps can be expected to increase tho foregoing diffl-cultias until they become very important.
The location of ~ho w% on the fuselage has p?mnounoedoffects on airplauo stabillty. El@ -w* airplanes tend to havemore longitudinal stability at medium and high lift coofficionts.The vertical location of the wing aleo influences the offeeti mdihedral @ vertical tail effectiveness appreciably (references 3and 4).
.
_“
.
The present paper is the first of-”aseries on an Investigationof the effects of powor, flap deflection, and vertical position ofthe wing on l~itudlnal and lateral stability and control. TIMresults presented herein fnclude only ,thelongitudinal stabilityend control of the model as a low-wing airplane,
COEFFICIENTS AND SYMBOIS
The results of the testw are presented.as etandard-NACA coeffi-cientt3of forces and rncamnts. Pitching-munent. coefficients are
.
given about the center-of-gravitylocation shoti In figure 1(26.7 percent M.A.c.). The data are referred to the stability axes, .which are a system of axes having their -ortginat the center of .
.
9
..
*
.
NACA TN No. 1239 3
gravity and in which Vge Z-axis 3.sin the plane 6f qmmetry andperpendicular to the relative wind, the X-axis is in the ylane ofshymnetry and PCrpcxiiicularto the Z-axis, and the Y-axis is perpen-dicular to the pkrm of symmetry. The po=itive directions of thestability axes, of angular displacements of th’eairplane and con-trol surfaces, and of hinge moments are shcvn In figure 2.
The coefficients and e~bols are
CL
%wcLw~
CL
%;
Cx
cm
cm.
c%
cInt
Che
~ct
Qc
v/nD
‘v
Vt
Lift =
lift coefficient (Lift/qS)
maximum llft coefficient
increment in lift cc%fficient
udcLslope of lift curveF
defined as follows:
due to flap deflection
horlzcmtel-tail lift coefficient (Lt/qtSt).
longitudinal-force coefficient (X/qS) “.-..
pitching-mqent coeffi:lent (M~@cr).... .. .*.
tail-off ~itching-moment coefficient . .
pitchhg-mcmmnt coefficient about the effective Ixill-off ““aerodynamic center ._ .__..A
pitching-manent coefficient proviacdby the tall(Cmtau on -~tail off)
--.—
elevator hinge-mcment coefficient (~/qbef~e2].-
effective thrust coefficient based on wing erea (Teff/qS)
torque coefficient (Q/#D3)
propeller advance-diameter re.tio
2ropulsi-reefficiency
horizontal-tail VOIUUR
-z
(TeffV~~Q)—
--coefficient (StzttJcl)
. .-
..
4
}xz
M
‘t
He
TefF
Q
w
Re
q
qt
s
St
c
cf
Ce
b
be
Zt
v
VT
v~
vSi
NACA TN No. 1239
forces along ws, pounds
mmont about Y-axis, pound.-feet
horizontal-tail lift, -positiveupwerd, pounds
elevator hinge mauent, pound-feet
Tropollor d’titive thrust, pounde
propol.lertorque, pound-feet
airplane wo@ht, pounds
effective Reynolds nmnber
()
~~2free-stresm dynamic pressure, pounds per square foot ~
effective dynsmic pressure at tail, pounds per square foot
wfng area ($)okk
horizonte&tail
airfoil secticm
sq ft on model)
area (1.92 sq ft on model)
chord, feet
wing mean aerodynamic chord (1.36 ft on model)
elevator root-mean-square chord back of hinge line (o.26~ fton model)
wfng span (7.458 ft onmodd) tiese otherwlso designated
eler’atm spem alq hinge line (2.546 ftcm model)
tail length measured frcm center oi?gravity to quarter-chordpoint of horizontal tail mean aerodymdo chord (3.29 fton model)
air velocity, feet per second
@dindicated airspeed, miles per hour ~~
rate of descent, feet pem second
Indicated rate of descent, feet per second
-,
.
.
NhCATN No. 3.239 !5
D
n
u
P
a
%
e
it
i5e
af~
%*
P
no
‘P
propeller dieneter (2.00 ft on model)
-propellerspeed.,rps
ratio of air density at altitude to air density at sea level
mass density of air, slugs per ctiic foot
angle of attack of fuselage center line, degrees
angle of attack ‘oftail chord line, degrees
eagle of downwash, degrees
angle of stabilizer with respect to fuselage center line,positive when trailing edge is down, degrees
elevator deflection, degrees—.--...
deflection of forward part of dotile slotted.flap withrespect to airfoil chord, degyees —
deflection of reerward par; of double slotted flap withrespect to forward part, degrees..- ,.-. .. —--..,..-..
Propeller blade angle at 0.75 radius (25° on model).-
tail-o~f aerodynamic-center location, percent wing meanaerodynamic chord —
neutral-point location, percent wing mean aerodynamic chord(center-of-gravity location for neutral stabtlity in&mmed fli&t) -
Sulscript:
b trirmwd conditions with
MODEL
center of gravity at the neutral point-.
AND APPARATUS
The tests were made in the Lsmgley 7- by 10-foot tunneldescribed h references ~ and 6. Ii; liuxling-gearwas us6tifor
..
the %ests. Figure 1 is a three-view drawing of the model. Thewing was fitted with a ~-percent-chord double slotted flap covering
—
93 Qercent of the span and was designed frcm the data of reference 7,For the flap-neutral tests the flap was r6tracted snd thb”~aps werd––. “ ~Yaired to the airfoil contour with mdeling clay. I?orthe s e-
%?slotted-flap tests, the rear part of the flap was deflected 30 ,.
6 IVACATN NO. I.-239 _-.>
and for tests with the double sloWm& flap both parts of the flapwere deflected.30° (see detail of flap In fig. 1). For the flap-doflected conditions, the gap between the inboard ends of the flap(dlrectl.ybelow the fuselage) was sealed with Scotch cellulose tape.
A moro detailed L-awing of tho tail assembly Is shown infigure ~. The horizontal tail had an inverted Clark Y sectionand was equipped with a fixed leadin&-@ige slot. Yhe slat had‘aconstant chord but was located to a~proximato.the best slot~hape given in reference 8. The reason fcr the unusually hightail location (figs, 1 and 3) is given in the mction entitled‘tDiscussion.”The lsolat~d tail was mount,ed.in.the tunnel as shownin f@ure k.
Power for the 2-foot-diameter, three-blade, right-hand, metalpropoller was obtained frma a ~6-horsepowerwater-cooled ~nductionmotor mounted fi the fuselage. Motor epeed was measured by meansof an electric tachometer. The dimensional characteristics of thepropeller are given in figure 5,
Elevator hinge mcments were m.eesuredby means ofian electricstrain gage mxznted in the stabilizer. The &jmmnlc pressure enddcwmwash angles in the region of the tail wm’e measured.with abank OZ pitot-pttch tukes co&cted to a diract-readingmultiple-tubo manometm.
TESTS AI?D,RysuL’iEl
Test Conditions
The tests were made in the Langley 7- by 10-foot tunnel at Ieic Pr~ssweU of 12.% po~ds per sqw=e foot for the powor-ontostm with tho double dotted flap and of 16.37 pounds per ~quarefoot for all othGr tests, which correspond.to air-speeds of ahnut-70 and 80 miles per hour, respectively. The te~t Reynolds numberswero about 875,000 anil1,000,000 based.on the wing mean aerodynmnicchord of 1.36 feet. Becauee of the turbulence factor of 1.6 fur thetunnel, the effective Reymol@ nuuihers(for maximmlift coefficients)were about 1,~0,000 and 1,600,000. ~
Camections
All powor-on data’haye been corrected for tares caused by themodel support strut. No tam corrections wGre obtained for thepower-off tests because they have been found to be relatlvol.ysmalland erratic on simflar models wfth flaps defl~ctod; thus cmissbn
—●
-b.
lU.C!ATN NO. =39 7
of the power-off tare correcti~ is not believed.to change seriouslythe resulte. The test results for the isolated horizontal tail we~corrected for tares obtatied %y @sting the tail aesembl.ywith tie –horizontal tail removed. Jet-boundary correcticms have beefiappliedto the angles of attack, the l-i tudinal-force coefficients, th6tall-on pitching-manent coefficients, end t.h3d,ownwashangles measured.by surveys.
The corrections were ccxrputeda~ follows:
()%&m
mm= -57.3 —- ~ _S—vq q ~ c ait CL
Jet-boundary correction factor at wing (O.1125)
total jet-buunilarycorrection at tail (varies between=a o .210)
mcdel w!! area (9.44 sq ft)
tunnel.cross-sectional &a (69.59 sq ft)
??cmpit chanae in pitching-mcment coefficient _perin stabilizer setting as detemnined ti
qt/q ratio of effective dymamic pressure over theto free-stream dynemi.cpressure
0.200
degree chqngeteats
horizontal tail
-All corrections were added to the test data. The equations forthe pitching-nmm?nt and downwash corrections are explained in refer-ence 9. .
. . ._ —
.
.
.—
.—
8
Proceduzm
Propeller calibrations were made by measuring the longit-nlforce with the model at zero angle of attack, the fla~ neutral, andthe tail removeiifor a range of propeller speeds. The effectivethruBt coefficient was then computed fram the relation
Tel- ~(proyeller removed)= cX(pr~elle,r oPerating)
Motor torque was also measured smd propeller efficiency was ccm-puted. The propeller calibration is shown in figure 6.
Power-on tests were made with Tc~ varying with CL according
to figure 7. A straight-line variatiti of Tct with ~ was usedbecause this mrlation approximates the variation for airplanes withconstant-speedpropellers operating under conditions of constantpower. Preliminary tests were made %y setting the propeller speedto obtain a given value of Tog anctthen varying the angle ofattack a until the value of CL corresponding to the set Valueof Tct} indicated in figure 7, WEEIread on the scale. Subsequentpower-on tests wtth the same flap setting were made at the ssmspropeller speeds amd angles of attack as the preliminary tests.
The approximate amount of airplane engine horsepower repro-senteclIB given in figure 8 for various model sceles and wingloadings. The amount of powor represented was ltiited by themaximum output of the model motor and the.deeire to keep the tunnelair velocity as high as practical so that a reasonable value ofReynolds number could.be maintained. The amount of airplans powerrepresented will be found low for many cases.
The value of TC* for the tests with the propeller tind-mlllhgwas about -0.00~.
Presentation of Results
An outline of the figures presenting the test resultE 3s asfollows:
TigureStabilizer tests. . . . . . . . . . . . . . . . . . . . . 9-11Tuft studies (double slotted flap only) . . . . . . . . . 12Effect of removimg flap sections . . . . . . . . . . . . . 13Landing characteristics:Effect o~owerandflaps . . . . . . . . . . . . . . . 14Effect ofscaleandwing loading ...,.... . . . . 15
.
.
●
NACA ~ XO . 1.239
.
FigureI’ieutrsl points:Effect of flaps . . . . . . . . . . . . ... . .. . -.,. 16Effect of power . . . . . . . . . . . . . . . . . . . . . 17Increments due to power . . . . . . . . . . . . . . . . . 18
Stability parameters:Effect of flaps.... . . . . . . . . . . . . . . . . . 19Effect of power.... . . . . . . . . . . . . . . . . . 20Increments duetopo~r. . . . . . .-r...... . . . 21
Air flow at tail (&ouble slotted flap only):.-
Dynsmic-pressure contours . . . . . . . . . . . . . . . .22 - 23.
Downwash-oontours .Isolated-tail tests .Elevator tests . . .Illustrative solutionStabilizer tests .Chart for graphicalVector diagrams for
● ✎☛☛✎✌☛✌✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ● ☛✎✌ .24 - :~● .**... .s . . . . . . . . . .
. . . . . . . . . . . . ..0. .27 - 2g:f”.qt/q ena E: .● .8 “.. .*.. . . . . . . . . . . 30 “--method . . . . . . . . . . . . . . . 31neutral-point equation . . . . . . . 32
Lift
DISCU3SIQN
Characteristics
The following table shows the effect of flaps aniipower onlift characteristics (figs. 9 to 11):.—
~L
If%-- “-%‘--”
FlapOperating tail off tail off
1condition
(Ct= 0°] I (a = 0°) (a =aoo)
\NeutralSingle slottedDouble slottedI?outralSingle slottedDouble slotteaNeutralSingle slotted.Double slotteti
-1‘~Proyel.leroff .
-J
1
{
Propeller windmilling
>Yower ~
J
0.271,342.14.27
1.332.14,25
1.472,54
----
1.071.87----
1.061.87-----
1.222.29
0.072.086,074.074.085.074.087.og’7.108
—..
Maximum lift was not attafnod for all conditions; hence ccm-pari~on is not possible. Values of trim lift incremon{s not pre-sented In the preceding table will be lower than untrhmned liftincrements hece.useof the large down loads required of the tail-.
.
.
10 NACA TN NO. ~39
From the foregoing tible it can be seen that with flapsdeflected. the application of powm’ caused a mwked increase inMft-coefficient inorcmsnt (0.26 with the single slotted flqand O.k+with tinedouhJ.eslottid flap). I%wer also produced aconsiderable increase in the slope of the untrimed lift curves,especially for the double-slotted-flap condition. The noticeableeffeet of power with full-span single and double slotted flapsdeflected can he explained, in part, by tie increased dynamicpressure over the wing associated with tie high lift coefficlentsand by the improved flow over the rear flap as shown by the tuftstudies of “fi@ro 12. Witi power off, large parts of the rearflap we stalled throughout the angle-of-attack ran@@ although therear flap uns=lls when the main part of the wing begins tostall. The effects of the model scale me such that the fti-scaleairplane may not e.xperieme a stalled rear flap.
The tunnel-wall effect and the Reynolds nuuibermay be con-tributing facjxm b m.king ‘&e wtng tips stall firs+ Ccmputa-ttons indicate that the induced wpwaah at the wing caused by thetunnel walls itmreased the effective angle of attack of the tipabout O.3CL degrees thus giving the wing an effective washin.
Tests were made with the ~in~e slotted,’flap to determine theeffect of removing the section of flap beneath the fusela~(fig. 13). The sketches included in this figure show the [email protected] used. An appreciable loss in lift at a given angleof attack occurs with the gap of 8.1 inches. Although 12~ percent
of the wing area is included in the removed pert ofithe flap andof the wing i?modiately ahead of thie flap, the observed loss inflap lift incremmt is only about ~~ percent; thus apparently
over 50 yercent of the flap lift Incremmt is cszried across the*P “ For the 6ap of 0.6 inch no change .WUSobserved in lifti
Landing Charac*ristics
Landing characteristicswere computed for the mdel based onan effective Reynolds number cf 8,000,00Q (approxiutely full size).It was found that a wing loading of approximately 90 pounds persquare foot could.be attained without exceeding tho rocommmdedmsximum rate of descent of 25 feet per second (reference 10) withpower off amd either with flap neutral or single slotted Flapdeflected (fig. 14), With the double slotted flap deflected, awing loading of approximately 40 pounds per square foot may beattained without exceeding a rate of deecont of 25 feet per second,
--
.NAOA TN No. ~39 33
With the application of Tower corresponding to the horseptie%-” ‘- ““-in figure 8,with flap neut@, and with single slotte+ flap deflec~~the atrplane will tend to gain e+ltitudeover most of the lift range.
The power required to ~intaln aritiica.ted rate of descent of25 feet per second at 0.8- (reference 10) and at various wingloadings is shown in figure ~ for three different mo&l scales(l/k, 1/5, and 18 SCd.eS).
(This f@ure, derived.from the mcilel
data of figure 1 , also show the wing hadLngs that may be attainedwithout exceeding a msximum rate of descent of 25 feet per secondwith power off. With the application of flaps the power must beincreased to maintain an indicatedsecond at a given wing location.
‘Longitudinal
rate of descent of 25 feet per
.- -. —
Sti.ility
Method of analysis;- The static longitudinal stability cf thenmdel-i~~.icated By the plots of the variation of neutrel-pointlocation with CL (figs. 16 am17). The neutral points wereobtained by the methcds given in references 11 and 12 ‘fromdata-”shown in fi~s 9 to 11 and 27 to 29.
—
From the aforementioned references”it canbo seen that thehinge-zuomentcharacteristics of the tail are detenuining factors incalculating stick-free stability. Because hinge-?ncmentparameters
—
can vary widely for similar tail plan forms, details “ofthe stabilitycomputations will be concentrated cm the stick-fixed condition.
The quantities which affect the static longitudinal stability(stick fIxed.)hav~ been separated into the vaious caaponents of
. -—
the following Cquation:
The derivation of equaticm (1) Is given in the appendix. The termsof the equation, which have been found useful in analysis, are
...
12 NAC!ATNl?o. 3-239..
referred to herein as static-longitudinal-stabilitypummeters. Thelo~itudinal stability pammeters were obtain@ frcm the tail-offand stabilizer tests and isolated tail tests presented herein. Asthe slope of the lift curve for the tail is nonlineav, a specialmethcd was used to ccaqmte qt/q ant c at the tail. (See apyendix.)The effect of flap deflection and power oh the paremeterflare pro- .Qented. in figure 19. l’hesme results have been replotte~fn fig-ure 2U to show the efifwotof yowsr at various flap deflections,Results of surveys of dynamic yressum and downwash WIes mde withthe double slotted flap are shownby points tn tha plots of fig-ures 19(c) and-20(c) for comparison. The surreys, however, wcromade in only two vertical planes 6 inches on either side of the mdeloenter line and thus do not represent averages across the span as dothe values obtained frcm sta.bil.izertests. In the subsequent discus-sion the effect ofiflap deflection and power on the neutrel.pointlocation will he explained by means of the parmeters.
@~~derattons inv~~~. 10C~tiOQS- prel~ esti-mates oblxdnod from the air-flow surveys of-figures 22 to 25 showedthat the nmdel with the double slotted flap would be very unstablewith power on at all.lift coefficients if tho tail were placed.Inthe conventional low position. The matn destabilizing influence ie8hown by the third term of’the right-hand side of equation (1) whichwould produce instability at all lift coefficients instiad o~%ml-yat high lift coefficients. The lar$e ne at$ve value of-c% com-
ayq*/q)bined with a normal positive valuo of —
de!.when the tall is in
●
the slipstream results in a large dest=abili~ingefi%ot. For thisreason the tail was placed as high as practical In an attempt to
@?@
?remove it frcm he slipstream end thus to reduco - to a low
A gt/q) MLvalue. (see in fig. 23.) As shown in figure 20(c),
@@ f!CL
dCLwas reduced to a low valuo and stahilit~ was maintained up —.
-.
i
to a fairly large valuo of lift coefficient. Lowor and more favor-abla values of AC/M- would also be encountered at the higher taillocation (fig. 27).
Effect of tail slo~.- The use of a slot on the nose of thohorizontal tail improved the stability as shown in figure U by thoincreased slope of the Cm curve over that for the hil with ~h~
slot filled. This stabi~zing effect is explained by the isolatcd-.
tiil data (fig, 26) whfch show a hlg.hervalue of dCLt/~ for the
slot-open condition. The neutral points presented for flap neutraland single slotted flap were obtatied with the tail slot fill~d but
.
the neutral points for the double slottezlflap were obtdned wtththe tail slot open.
IWCATN I’io. 3-239 13
Effect of flap deflection.- With power off, deflecting theflap ~h~fts the neutral point reerward so ‘%hak“Kh6-6~biUky isslightly increaeed. Onc cause of the rearward shift is shown infigures lg(a) SJNI is(b) to k the shift in ~ with flap deflec-“Lion. In the case of’the double slotted flap another i?actorwhichcontributes to the rearward shift of ~ is the fact that tke tailslct was open and the’dope of tl!!tail lift curve wms thusincreased. The lar
g.~;r ‘f~ is of little signific=c~ ‘“irith
~ower off because —— is anal?.. With lower m, the same% _.
stab11.iz @q trend Of flap deflection is shown except that apcculia~ nmzt~al-poi.ntvariation is shown for the single sldtodflap (fig. 16(c)). The neutral-point v~iation titi single slot%e~” - -flap was tracad to bhe v~”ia%ion of AC/dcL (fig. 19(c)) with CL.
—
Although the stabilizing influence of ~ became greater as theflaps were defh cted with power ~n, the increase in dCL/d r~d~ce~the rearward shift of neutral point caused by tho flaps to about thesame order of magnitvb a~ the shift with power off (fig. 19(c) andequation (1) ) . .— J---
~ffect of p~we??.- When the propeller is added and allowed towindmill, the nsutrfl point shifts forw~ letween 1 - 5 p~ficentmean aer@dynwnic chord-(fig. 17). About 1 percent Gfneutral yoint was traced to the forward shift of ~propeller was added. The remainder of this shift canfor by the slight increases in de/da and (dCL/da)b
windmilling (fig. 20). “
this ~hift in—
whsn thebe accountedwith propelleti
The atiplicationof power with flap neutral sh+<ts the neutralpoint no mora ths,n1 percent mean a.crodynemicchord owr the wind-milling condition (?igs. ST ma 18). The destabilizing influenceof the increa~eii de/da and d% /da a~parently s o:fset by the
d(@2 istabilizing influence of ~, !lt/% ad * (figs. 20(a)
ana !21) . With the single slotted flap the vari=tton of neutral—
point with power on, as previously aiscussea, makes the fici-ement ““due to power ve~ erratic. With the double slotted flap the effectof power is.very small up to a ~ of about 2.3 beyond which the
powsr-on neutral point moves rapidly forward (figs. 17(c) and 18\.AH is the case with flap neutral, there is a bal.snclngof thestabilizing and destabilizing effects. The tail-off center ofgravity ~ shifts rearward about 15 percent mean aer~tii~chord but this shift is offset primarily by the destabilizingeffects of the increase in d,c/d.cLand (~/da)% with power
14 NACATN No. 1239
(figs. 20(C) ana 21). At high values of ~ the rapid forward.movement of the neutral point seems to %e caused-by several ofthe parmneters. The value of no.. moves forward quite raphily;
..
W qt/’~)-.—.
dcLvalue of
the last
increases and, fn ccmbinatim with the Wge negatfve
c~, produces a }.areedestabilizeing effeet as shown by
term of equation (1).
Longitudinal Control and Trim
Gince the tail-off pitching-ncment coefficients are highlynegative oapecially with the full-span double slotted flap(fig. 11~, the tail load for trim is very large. PreltiinarYcalculations showed that with the conventimal tail size used,the tail would stall-when the value of ~ with flap down waareduced to a moderately low value. Zn order to prevent theearly tail stall a leadi~ -edge slot was installed in the tafl.According to available data, a slot is more effective on camberedsections. For this reason a cambered section (Clark Y) was wedfor the tail. Tests of the tail with and without the nose slotfilled showed that a large negative angk of attack end lift coef-ficient were obtainable with the slot opon (fig. 26). The ClarkYsection was moun’bd inverted since the tail load with flap deflectedis down. An airplane having a slotted tail woul~ probably alsorequire an adjustable stabilizer to obtain the advantage of theclot. In addition, the slot was assumed to be retractable so thatthe slot could be closed when the airplane was cruising with flapsneutral.
The angle of attack of the horizontal tail can be obtaindfrcm the fol.low~ equation:
at=a+it-~
For the dotile slotted flap with power on ati = -8°and C
Lb= 1.46, q is ccmputed by using figures 11 and 19(c).
Thus,
at = -8° - 1.30 - 8° = -17.3°
Reference to the Isolated-tailangle of attack of -17.30 iscase but not for the slot-openapparent in the Cm of figure
data of figure 26 EOKYWSthat a tatl. .
beyond the stall for the slot-filledcase. Altllou@ the tall stall11, tail stall is indicated by
is nctlthe
.
.
--
-.
.
NACA TN NO. 3.239 15
sharp rise of elevator hinge moments with the nose slot filled.Of course, at a value of “CL lower then the value tested, thetail with the nose slot open would alsc stall. ~1 wo~dBe_.indiodeti_to_the-pi,M3&t3y-a-sudden..mcc_*ollAbwendency ofthe airplane to divjL Even with the slot open, forward movement“ofthe center of gravity would be seriously limited with thedGuble slotted flap because of excessive tail loads required for _trim. A larger tail volume would @prave this situation.
Elevator effectiveness (figs. 27 to 29) is nomval emd aboutthe same for each flap deflection except the double slotted flapwith the tail slot open. The low elevator effectiveness with thedouble slcitte~flap is expla-inedby comparing the isole.ted,taildata with tail slot open ti filled, (See fig. 26.) The par~tersac~ /da. end ~/d8e sre smaller with slot open in the ~-
rangc through which the tail is operating. Elevator effectivenessincreases for the power-on conditions at the.higher val+es of CL
-r
where the tail enters the eiigeof thq slipstream. .—
In smumarizing the importance of the tail in regard to bothstabillty and control, it apyears that raising me tail to provideadequate stability removes it frcm,regfons of higher dynemlcpressm%s which are necessary for providing control in the caso ofthe tail tested. Control fs possible with the tail as tested,provided that the flaps are deflected gradxm.llyto avoid a possibletail stall.
CfjNCLIEIONS
The followlng conclusions were reached with regard.to thelongitudinal characteristics of a low-~ry$, sin@e-engine mcdelwith full-span flaps and an elevated horizontal tail:
1. With flaps deflected, the application of power c~a amarked increase in lift cmfficient incrment (0.16 for the singleslotted.flap and 0.42 for the double slotted.flap).
2. Power increased the slope of the untrimmed lift curves(O.034 increase for the double-slotted-flap case).
3. Deflecting either the single or tlouble slottea flapincreased the stability slightly with power off.
.
16
4. Addfng the windmil..lingpropeller shiftedforward betwmn 1 and 5 percent mean aerodynamicshifted tho neutral point no more them 1 percentchord with flaps neutral.
5-:With the H@@’ slotted flap, power was,dmstabillzing and the offoct varied greatly with
NACA TN ?70.1239
the noutra2 pointchord. Powormmn [email protected]
in gmeral,lift coefficient.
With the double slotted flap, power had cmly a very small effecton stabi.lftyup to a lift coefficient of about 2.3 when the neutralpoint moved rapidly forward, “Thosuccess In o%tahing power-onstability for most of the lAft coefficient rango was attributed tothe tail being out of the slipstream.
6. Elevator effectiveness was atiqute and normal wtth flapsneutral and with the single slotted flap. The stabilizer noseslot,which was open with the double slotted flap tiflectod, causeda low elevator effectfveneas.
.-
-.
7. Tho stabilizer nose slot delayed the tail stall with thedouble slotted flap. Forward center-of-gravity travel woulfi boseriously United, however, even tith tho stabilizer slot oponbecause of cxccssive tail loads reqtirod for trim.
8. A larger tail volume would prcmido ammo satisfactorycontrol for the particular airplane mod,el,especially at the forwa@center-of-gravitylocatfons where larger downloads will be rcquirodby the tail for trti.
●
ILmgl.ey Memorial Aeronautical Laboratory
National Advisory Ccramitteefor Aeronauti sLangJ.eyField, Va. , octot~r 29, 194&
.
.
..
.
-,
.
APPmmx
METHOD OF 0BTA3NIKG DYNAMIC PRES3RE 4NDDOWNW.. AT T.KE’I!AIL
WEEN TEE TAIL L33?TCURVE IS NONL~EAR ARD IIERI’VAT3XZ?
C!l?NETFIRAL-20~T EQTMTXCW
Tabular procedure for determining qt.q snd ~ .- A simple
and commonly used method for obtain3mg-the &Y ective _ic -preesureratio q~/q, especially when isolated-horizontal-talldata are
lacking, is .asfollows
,
~’here( 5’) is the maxianm value cbtatned by use of propeU.er-
\ ait)mx
off’stabilizer curves (propeller-windmillingstabilizer curves maybe used b the absence of propeller-off data). The value
—
of ()d~’may be estimated.frcm the slope of the tail ltit curve --
irt>-
obtatied from tests of the isolated tail or estimated frcm theaspect ratio of the.tail. The effective downwash angle c, in theabsence of Isol.atid-horizontal-taildata, may be obtained from thefo~mning equatjms:
.-
(A2)
(A3)
When this method was applied to the present model, the agrcmmantbetwmn q~/q and c obtained by survwys made with pitot-pitchtutiesand cmwpvte~ values of qt/q and c was found to bo vwry poor.This discrepancy was trace~ to the fact tiat.the elope of tha taillift curve wes not linear, especially with tho tail slot open(fj~. 26), as was assumed with the fore~olng method of coupuhtlon.In orhr to deal witlhthis situatim a method of computation wasdeveloyed for which good agreement-was obtained.with the a~uw>ys(fig. 39). Tn add3,tion.to test dab obtained with tall off end WJth@o stabilizer se.ttin~s, test data are ?wquireciof the tall lifbcoeffj.cimt against tail an~le”of at+=ck. .
At eny one angle of attack the pitching-mcmmt coeffic bnt Cmt’
from which
Likewise, at any one angle of att&ckJ a char@e b= .st@ilizerIncidence will..resultin a change in [email protected] Uf t“cosffj.c-ien~&~Jt
correspondtig
from which
change in pitching-guxnentcoafftil.mI?i_ACm, or
/Lcm= c%
- Cml
. .... . . —..,—----
f3t. - ACm/Vt—=-— (A5) .q ACL
k
NACA TN No. 1239
where
19
When tlieisolated horizontal tail possesses acurve slone, the effective dynsmic-pressme ratio
Constsllt llft--..qt/q may be
determined directly hy divi.tingboth sides of equaticmk5) by .A}t
and trSnSTOB@; thus
where d~/dit is determined fran etabillzelstests and %t/@t. is determined frcm isolated-tail tests. Equation (A6) is an
improvement ovei equatim (Al.)but is based on the assumptfxm thatth= slope ot the lift curve is linear throughout the tail-angle-. .of-attack renge. Tm cases where the horizon-l tail does not -possess linear lif’t-clrvech~actaristics the solution is not so.
●direct. In attompthg to use equations (A4) and (A5), the tailvolume Vt may be ohtatned from Mmensicms of the model,-d thevalues of’ ACm end Cmt may be determined frcm the wind-tunnel
data at any one angle of attack; however, three quantlties remainrmknowm, nanely, the related values cLt> %t~ ~~ q#q . Since
there are cnly two equations, a direct “solutionis not feasible.The followjng successive approximatfcam are therefore made:
.—
.
(1) If Vt, ~t, SIId ACm have been obtained for sane me
angle of attack, a first approfi”matianof qt/q 5.sobtained from
equatinn (A6) by using an average value of dcLt/da~ frcm isolated- ●–
tail data.
(2) upon Su%stitum’lg qJq into equation (A!), solvingfor CLtl, end refer~~ingto the isolated-tail lift c-e (fig. 26) ‘
.to dete~ne the corresponding tail an~e of “atb~k ~,
.-=O -tiil
sngle of attack at i. ~ ~ be obtained from the relationship.
(A?)
20
..
HACA‘ZIJNo. 1.239.-
(3) BY refem@3 to tie isolated-tail lflt curve, the valueof ~ that corresponds to is determined; the evaluatkm of_.
t~ a%.-
C.
A% ~=%%-cL~
is thsn made poesible.
(4) Upon substituting the value or- A~t Into equation (A5),
the VSLU9 of qt/q is obtaingd. If this value of qt-q ie
numerically equal to tho value obtained in step 1, the df~ctivevalue of qt/q hae b~en found.
Sty)e 2 through k ● A more rapid convwxyace i~ sometimos found tooccur if the average ofie lemt two values of ~i,/!lare Ned forthe next approximation.
(6) Steps 2 through .5 are repeatx”di.mtfl two successivevalues of q~.q aro in agreenent wlthfn the accuracy of the data.
The ef’fectivodynamic-pressureratio has then hem deter~lned.
(7) ~en the eff~?ctivedynamic-pressure-ratio has beendoterfined end +he value of at csn :hefibe obtiiiiedfrm
1
fi+gure26(c) the downwash angle is obtained fra the rdation
(A8)
Table 111 presents a solution for qt/9 ~d ~ for ~~sngle of attack of the model (fig. l) witi double slotted.flapBtown and power on. The pertinemt aerodynamic dsta axe pregenLed inf~gures ~-and 26. The procedure for obtalntig additicmal datanemdeflto determine qt/q and c ia Kiluktidted in figvre S. !J!h
initial approxitnatfonof qt/q was obtaxd by ~fig equati~ (~)”
Graphical ~rocedure for debminfng qt/q and ~.- ~c use of
e. tabular -procedurosuch as exemplified by the Illustratjve solutlcnof @ble 111 will be found rather tedious when a rmge of angle ofattack emd flight conditiom is being investigated. In order tor~duce appreciably the time and to simplify the solutlcm to mane
.
--
IWCA~ No. 3239
extent, a chart has beenof @K! and.tail an@e
21
prepared.for ddxmmining the valuesof attack graphically. This chart, -. —. —
shown as two separate parts by figures 31(a) end 31(b), has beenfound to be very effective when placed side by side with thefsnilies of curves laid out to about twice the scale of f i,gure 31.
The fa??ilyof curves ti the upper yert d’ figure 31(a) is thegraphical representation of equation (Ak); the Icme curve in tielower part of figure 31(a) is a specific isolated-tail lift curvefor the model in question. The fsmily of curves in figure 31(b) isthe graphical representation of equation (A5).
In order to use tio chart it till be found desirable to set upa tible such as table IV in which ,tiefirst seven colums are the-me as those of ‘able 111” =&-@-~~~ Of at@k , horizm~
%%reference Ilnes corresponding to ‘thevalues of —
v+ v~
given @ +abl~ TV should firsthe drawn as shown in figures 31(a)end 31(b). These two lines “forn””therGf6retic”elines for thesuccessive approximations for the ~cdel angle of attack concerned.
By use of the model data considered in illustrating thetabular apyroach of table IV,
Ee titersectim of the first ap~oxi-
mation of qt/q [1.494) with < (O.985) should now be located41
in figw?e 31(a)j th first approxfmatim of ~t is thus determined.
By projecting t.$isintersectkm down to the isolated tail lift curveand using a specially devised cardboard or celluloid scale (shownin fig. 31)having sidgs at right angles to each other-and graduatedto conform to the ortites ti abscissa of the lift curve, theval~ ~ ACLt (0.403,)resulting fran @t (8.3°) (see fig. 30) is
readtly deterntiad (fig. 31(a)).
At the interaecticm of this flr~t approxiumtion of ~CLt (O.403)
wifi ~ (> .496) tn figu~-e 31(b), the secctudapproximation of qt/qVt
may be read f rm tie ?mttm s{ .=o. Sipce this mcmd approximation.. of 9+1 is ~~t ~ ~ ~.,>nt #&-& ~a fti~t approx~timl, the -.
entire procedure is remamd as many times as is necemmry” to obtain:--?
. a@aement betwe= two consecutive values w? qt/q. Xasn theprocedure is contlm~ed, the lest vssue of,-qt/q oltiined.should be
used for the next successive ayprurlnatim.. Althmgh fig’L~B 3~(a).
and 31(b) merely show by means of the dashed lines ‘tkework for .-
obtaining the second Wqproximathl of qt/q; table IV gives the
enccossive values of qt:’q ~d A%iv obtained m well as the
fWal anawer fOr q+~q and c. “The value of c is obtained.
fyo.n at., wh,i.chshould,be read from the Ml liYt curve
(fiq. 31(a)) during the final a~proxiqat.ia.
r~flultingfrom the uae of the approximate method formerly used toObtxdm qt/q by assuming n linesr WuLl lift curve. The preeent
rcfined method gives a velu.eof q~/q = 1.115 (COIWUO (19), @ble ~),
whereaa the approximti mathod.gives a.value of’ q~/q = 1.494(column (7), table IV) cm akmt .38-percenterror.
Comparison of the tabular and graphical procedures fordetermininfl q%/q ma e ● - The graphical eolutt= as prnsente&
provides a vary good degrvG of ‘accuracy. Comparlscms between thetabular approach, such as table 111, and the graphical approaohto the solutlan of Gt,jq snd C at the tafl for various models hasshown consistent agrmmcnt through the second decimel plaoe. Theuse of tha gra~ical approach pormlts a bot.terthan @ -porcent sav~ngin timo whwn compared to a tabular soluti.m v=fng a sllde rule, andshout a 40-nercent saving in ttie when comp.red to a lxdmflarsolutionusing a calculp.tingmachine, particularly whEJnthe tail Uf t-curv~)is ncmlinear.
Nautial -mint equetion.- A neutral point fs defined es e center-of-~avitiy locathn for ~ch the curve of ~ against ~ has zero
Rlopa at the trim lift coefficient%
. The measurement d tho
slope ~/cL ~it,h~fl off C~{, gives Khe tail-off aerodynamic
c~nter no; wi+h tail cm, Cw gives the neutral point ~ ● (ss0
fig. 32(a).)
—
. .
.
.
--
%
NACA TN No= 3.239 23
The tam C~ represents the pitohing moment of the wfng
fuselage about the tall-off neutral point no at trti. (This termmay be evaluated from the tail-off pttohing-&mentfigure 32(b).)
Differentiattig equation (@) wtth respect to
data obtained fromi
..
The derivatives are to be evaluated with the trim variation of Tc f
With CL. Solving equation (A9] for v ~%t
and substituting in
equation (AIO) yields
~-ylo.
solving for
L_.
%e+-_ .-
1‘1 -1
CL a.(qt/q)kt/q
ac4L l%
Derivation of (d~/ti)b ● -rThe mm (d~/d~)b is derived as
(AM!)
fell~vs (see fig. 32(c))!
..
24 NACA !L!?iNO. 3$?39
.-
c%“
Ih order to use the preced.in~equation, the neutr~ yotit must belalown●
.
.
.
.
.-
-.
NACATN 110.1239 25
INFERENCES“
1 ● Mill&m, Clark B .: The Influence of Running Propellers onAirplane Characteristics. Jour. Aero. Sci., vol. 7, no. 3,Jan. 1940, Pp. 85-103. (Discussion,pp ● 103-106.)
2. Recant, Isidoro G., end Swanson, Robert S.: Determination ofthe Stability and Ccmtrol Characteristics of Airplanes frcmTests of Powered Modeb. RACA ARR, .July1942.~
3. Sherman, Albert: Interference of Tail Surfaces end Wtng endFuselage from Tests of 17 Combinations in the N.A .C .A.~ariable-llensity Tunnd. NACARep. No. 678, 1939s
—
4. Wallace, Arthur R., and Turner, Thanas R.: Wfnd-TunnelInvestigation of Effect of Yaw gn Lateral-StabilityCharacteristics. V --Symmetrically Tapered Wing with aCircular F@elage Having a Horizontal and a Vertical Tail.NACA ARR NO. 31’23,1943.
5. Harris, Thomas A.: The 7 by 10 Foot Wind Tunnel of theNatimal Advisory Committee for Aeronautics. NACA Rep.No. 412, 1931. —
6, Wenzinger, Carl J., end Harris, Them A.: Wind-TunnelInvestigation of en N .A.C.A. 23012 Airfoil with VariousArrangements of SlotteklFlaps. NACA Rep. No. 664, 1939.
7. Harris, ThomaG A., and Recemt, Isidore G.: Wind,-TunnelInvestigation Of EACA 23012, 23021, and 23030 AirfoilsEquipped with 40-Percent-Chord Double Slotted Flaps.
.—
NACA Rep. No. 723, 1941.
8. Weiclc, Fred E., and. Wenzinger, Carl J.: The Cheractirlsticsof a C&k Y Wing Model Equiyped with Several Forms ofLow-Drag Fixed Slots. NACARep. No. 407, 1932.
9. Swanson, Robert S., end Schuldenfrei, MSY’V~ J ●: Jet-Bow@-z’YCorrections to the DownWash behind l?oweredModels &Rectangular Wind Tunnels with Numerical Values for7- by 10-Foot Closed Wtid Tunnels. NRA ARR, Aug. 1942.
.
.
26 NAcilm NO* 1-239J’
M. CWstafson,F. 3., and O ‘Su$limn, William J., Jr.: The Effectof’High Wing Loading an Landing Technique and DistEuM@SWiWExporlmental Data for the B-26 Airplane. NACA ARR No. &K07,1947●
11. schuldenfrei, Marvin: Some Notes on the Determinaf,im of theStick Fiw3d.Neutral Point fram Wind -Tmnel Data. NACA RBNo. 3120, 19430 .
12. Schuldetirei, Marvfi: Scme Notes an the Determinatia of thoStick-Free Neutral Point from Wind-Tunnel Data. NACA RB
. No. 4B21, 1944.
.,:1I
~ACA TN No. 1239 27
.
T.ABIxz
MOQEL WING AND THL-SUREACE DATA
.
wingHorizontal Vertical -
tail tafl
Area, sq ft 9.440 ‘ 1.920 1.250Syan, ft 7.458 2.542 1.505Aepect ratio 3.91 3.36 1.81Taper ratio 0.445 0.438
%ihedmL, deg-----
5.8 0 -----Sweepbaclc, quarter
chord line, deg 1.9 ----- -----Root section ~W 2215 Clark Y (5.nmrt@&) NACA0009Tip section
bAngle of lncNACA2209 Clark Y (Imetied) I?ACA0004.5
tdenceat root, deg 1.00 -1.3 or 7 -1.50
bAngle of Incldenoeat tip, deg 1.00 -1.3 or 7 -1*5Q
Mean aerodynamic center, ft 1.36 --.-- -----Root chord, ft lJ?Q 1.141 1.272Theoretical tip chord, ft 0.80 O.m ---.-
%hedral measured with respect to ohord plane.bAngle of incidence measured with mepect to fuselage oenter line.
AIRP14WE
TABIE II
CONTROL-SURFACE
Percent spanArea behind hinge line, sq ftBalance area, sq ftRoot-~-square chord behind hinge line, ftDistance to hinge line from normalcenter of gravity,ft
1
DM!A
I
t
IH.Ovators Rudder
99.5 99.10.621 0.5060.131 MhllmUm0.264 0.353
3.721I
3.611
Flaps
93.0------------
----
XATIOIUL ADVISORYCOWITTEE ~R AERONAUTICS
—
lJAC~ TN ?S0. 1239
(1) (2) (3) (!+) (5) (6) m m (9) (lo)
a ‘=3 % % 2 > (?), %1 % %
itl- .l.p ~ .7.0” T.11&f V ~-% --”1 (9)+(1*-q
o -0.317 -0.* -0.W 4 .b% O.* 1.4* -0.659 .9.80 .1.53
{N (M?) (13) (W) (ly) (m (17) (lq
% f%). ~, %, ‘% %2 ~ (%J*–
ma MlCuria ‘u -‘o -i!% -i% -4’1 ‘s) + “+ - “J --?’ “n - ‘1’)
-w@ o.ko3 1.$W .0.&o -lZ.* AA 4.363 0MO
— —
(19) (m) (m) (m) (23) (!Ak) (=5)
(%)3 % ~ “ \ ~fi)x (-a : ‘:
-% -% --”’ (’Q +(: - ‘d -ma tall (s3)- (m) -~ .& h_wl
l.la -mm -U.99 -!J.@ -o.&p 0.442 l.in 0.373 -lb.@
(!23) (!29) (w (3U (32) (;) (*) (35)
% % @J, H:3 %1 % “% %
(30 (37) ,,(33) (39) (40) ($1) (k?) (hs
f+%l. (%). %. ~ ‘% % (~). [%7,, ..,- ,L, ,,
(39 - (3a I -% l’+%l-=w I (“’+(’%-it$)I -=11 (’~-+%0.445 I 1.U3 I -o.ea3 I -14.07 I -5.77 I .0.438 I O.uy I 1.US
%Effeotiw ; . 1.U5, driw ql . -WI
‘-”+%-%- 0 - 1.3- (-lk.11
- 12.@
IL4TIahLADvmmcatummm~
.
.
NACA TN No. 1239
-i
29
.
.
TABIEIV
TABIE FORUSEWE THE G~CAZ SOLUTIONOF ~
AEDEIXECTIVEDWNWASHMfGIEAT TE3H~TAIL
r
DYHAKCC—PRESURE RATIO
OF AH~PSX.SZ
IConflguratfon: Double ##lottedflap defleateiland power on.
(1) (2) (3) (4) (s) (6) (7) (8) (9) (lo)
C&n C%la %1 c%? c% ~ – (2), (?@l (:)2 P42‘t
o -0.317 -0.581 -0.841 4.496 0.985 1.494 0.&3 1.231 0.440
(1.1) (u) (13) (14) (15) (16) (17) (18) (19)
(:)3 p+, ($, (!4, (%)5 (!%!)5 (:)6 (%, (:)7
1.X27 0.442 1*122 0.444 1.117 0.445 1.115 0“% l.11~
Effectfve + - 1.117, since atl .- -14.1
G=a+lyql
- 0 - 1.3 - (-14.1)o
w x2.8
—
.- —
HATIONAL~coM!Iln!mFORAERoKMmrcs
-In.11111‘ 7i“Iq’
I
2.4 diem.
Wing area, +2 ft. . . . , . , 9.44
In4c, if....... . . . . ..i.36
cg,(/r@lf~.) . . . . . . . 26.70
‘h%?’? .. .. . .ffACA22157jp . .. ... ... NdC/I2?LV
Wiq incidence] dtg.. . , . . .1.”
iSi~kWl%kiitlffp &b,& s/oMf@Flap neulml
ROOT &c fiw -
6/.08 70& eiek?ituhinqe ~
. . . . . .
i%rusf
i- .
Figure l.- Three-view drawing of model as a low-wing airplane. All dim~dsions are in inches.
\
. . ; 1>
i i
. .
Figure 4.- Isolat4 tailassembly mountedtunnel,
h Langley 7- by 10 %oot
!I’i,1!
.
2..I&
NACA TN No. 1239 Fig. 5
4
.
.
.
./0 .50
.06 .40
,06 .30.
.02 ./0
00
Bhde ungle—(3et 25° Qt 0.75X9
h ~●
.
\\
#b<
\NATIONAL ADVISORY
COMMITTEEFORAERONAUTICS
40
‘G
o
.-
Figure 5.- plan-form ~~ bla-de-form c~ves for the model propeller.D, diameter; R, radius to @; r, station radius; b, section chord;h, section thickness. RAF 6 airfoil section.
.
Fig. 6 NACA TN No. 1239
.7
kf)“.3.4 .5.6 .7.8 s/0 /j~z
%ope//er adv~,ce -~j~~eti~ W+~O) ~n~
Figure 6.- Effective thrust coefficient, torque coefficient, and
o
.
—
.
●
efficiencyas functions of propeller advamce -diameter ratio for the ,
model of the low-wing airplane tested. D = 2.0 feet; f3= 25°.
.5
.4
.3
.2
.1
0
t 1
IFigure 7.- Variationof effectivethrustcoefficientwith liftcoefficientfor constant-power tests.
o .+ .(3 /.2 1.6 2.0 2.+ 2.0 3,2
Llff coefficient, CL
I
#.4
l..
Fig 8 NACA TN No. 1239
!$ ii t I I I I 1I /
u I I / scule /..8/ v
/ ‘I /1 A.
/
/
/ 448/ ‘
< 1111111 I I 1/1 1/1 / / / ~
G 111111[1 1/11/’Ml ‘ 3T3, /
0 I//A I
Figure 8.-Stamng
/60
/40
/20
o
—
I
.
20 304’05060BE?05U /t@Wing loudin9, 16/5?ff .
V&riation of approxQnate horsepower represented and .
speeds with airplane wing load@g.
NACA TN No. 1239 “ Fig. 9a —
-b
.
.
8-8
0
-4 0 .8 [6L;ff c$efficlen t, C~2
(a) Propeller off.
:2
-.1
0
NATIONAL ADVISORY
CONNITTES FtiAERONAUTS
Figure 9.- Effect of stabilizer setting on the aerodynamic character-istics of the model as a low-w~g airplane with flap neutral,6 = 00; tail slot filled.
mm ---
NATIONAL ADVISORY
COMMITTEE FM AERONAUTICS
(a) Concluded.
Figure 9.- Continued.
8 1
.
.NACA TN No. 1239 Fig. 9b
.
-.4 .8 /.2 L6~/”%Gbzfp/G/ L?flf, CL
NATIONAL ADVISORY
COMMlllES FM AEROMAIJTICS (b) Propeller windmilling.
Figure 9.- Continued.
——
—
Fig. 9b cone. NACA TN No. 1239.-
#-
-
ol4
-.
,
.
.
.
.
NACA TN No. 1239 .
~
.kl
8“$’b& /6b
ff
(c) Power on.
7/
o
.. /
Fig. 9C
,
.=.
.
.
Figure 9.- Continued.
Fig. 9C cone. NACA TN No. 1239
/-
. . .W
—
.
.
..
.
NACA TN No. 1239 ~ Fig. 10a
.
.
.2
o’
‘8
o
[ue- ln3- 0(7
: - /.3 N.tile ‘#A Opnm Off
I I
I
II I I I
I I
I , , ,
.4 2.0 2.+~?f f dk2f f ic j;;~, CL
“’TFFFHW
...
.’
...
-..
—&lL)
(a) Propeller off.
Figure 10. - Effect of stabilizer setting on the aerodynamic character-istics of the model as a low-wing airplane with a full-span singleslotted flap. ae = 0°.
Fig. 10a cone.
.
-. .-
NACA TN No. 1239
J-
.
NACA TN No. 1239 Fig. 10b
.2
-s+
‘..+ .6 1.2 16 2.0 ?,
Lift coeffic~en ~ CL
4
.
(b) Propeller windmilling.
Figure 10. - Continued.
Fig. 10bconc. NACA TN No. 1239
C3
Q(1
Cj
-. —
1
. .
.
.
NACA TN No. 1239 Fig. 10C
.
.
.i
0
71
72
:3
-.4
.+ .8 1.2 1,6 2,0 24 2.0
~/’ff coeff/~/ent, C&
(c) Power on. .
Figure 10. - ConWued.
Fig. 10cconc. NACA TN No. 1239 ‘
r
--—
.—.
.
NACA TN No.
C!E
+s
0
-.4
.-Q
‘.6
88u.
1239 Fig. Ila
\B-
~Tull off
t
/ NATIONAL ADVISORYCOMMITTEE FDl AESONAVTICS
.-
I 1 I I I f 1 1 1 1 , r , I
1.2 2,0 2.+ 2.8 3.2 3.6Li;; coefficient , CL
(a) Propeller off.
Figure 11.-istics of
Effect of stabilizer seWng on the aerodynamic character-the model as a low-wing airplane with full-span double
slotted flap. ~e = 0°.
--
—
.
. QI
G.20
.16
,12
.08
,04
0
, *I
, II
COyMlllEE FORAERONAUTICS
.0 /.2
-.
1.6 20 2.4 2.8
Lift coefficient, CL
(a) Ccmcluded.
Figure 11. - Continued.
I ti!
—.
3m12 3.6
I-JI-J
Pc)
iip
NACA TN No. 1239
.
g
u,-U.--
.
.
.
.%
)
.8 1.2 28 32 3.6Lif$6 coe%kien~+, CL
. .
(b) Propeller windmilling.
Figure 11. - Continued.
w.8 /2 /,6 2.0 2.4 2.8 35’ 3,6
(b) Concluded.
Figure 11.- Continued.
NACA TN No. 1239.
8
+-
5u.-
ii
.
Q-0
*
.
11-13%111.L
I -/.3 L .TW‘fFFFEEi
n
I
z-8
NAT!ONAL ADVISORYo
,8 102 2.4 2.8 3.2 3.6Lift !coef~gient , CL
.
(c) Power on.
Figure 11. - Continued.
.
.16
-/.3
./2
:08
7a
,04
0
COPllIIITTE~FM AfRONAUTICS
*8 192 1.6 2,0 2,4 2.8 3.2 3 b.Lift coefficient, CL
(c) Concluded.
Figure 11.- Concluded.
, ,,
. . . ..
* , I 1*
L-J B Unsteady
TT period;,
NATIOUAE. ADVISORY
COWTTEE FW KWAlmcs
(a) Propeller windmill@,
F@ie 12.- TuR studiesof the model as a low-wing airplanewith til-span double slottedflaps.
8fi ~ == 5f @; q . 12.53pounds per square foot
I
) u Sfal/,s and qnstalls,ranld n+ 4, ..+
gye>P$/een t t hQ
-, ...= .,, ,=~
cb=~.23-1
,56 u m stQ//~d CL= 2.+8:C=
CC= 6.+0 ~ Uf?s’teolfy T:= ’38 Tu.-fJg”
.
.
CL= /.56
T;= 26
NATIONAL AOVISORY
Comln-m w AERONAUTICS
(b) Power on.
~igure 12.- Concluded.
,.
1 I 1-1: ,il..”1
1
. y
. . I
NACA TN No. 1239 Fig. 13.
b
.
.
--
A
/d ‘d
/4 /6
0.6 “
-.
~ift cOQffik/&f, CLNATIONAL ADVISORY
COMMITTEE F~ AERONAUTICS
Figure 13. - Effect of removing flap sections beneath fuselage on theaerodynamic characteristics of the model as a low-wing airplane.5f ~ = 30°; 5e = OO; it = -1. 3°; propeller windmilling; tail slot
filled.
.—
16
15
).4
1.3
1.2
fl
1,0,3
‘,8
Q ;7
@ ,6
(7 .8’ 1.6 ?40 .81.62432,
CL at Cm =0
1+
a 1.6 24 32 40 M y
i :&.e ~Jo- Effectofpower smd flapdeflectionon the Emd@ characteristicsof the model as a low-wingsingle-engine airplane.
,,. .
‘“. , ,’ I
r.,11ii i “, 1
r_ !I,’. l’l , I .,,. -1 ‘--- —. —
● r
Flap neutral———— Single slotted flap
—-—- Double slo~~ed flap
Scale scale Sale
“o 1 2 3 of 2 3 40) j 234 5 6 7 8 9x@
77yu5t horsepower NATKUU-~
mnlmm~
Figure 15.- Effectof scale and wing loadhg on the power required to ?naMsJn an indicatedrate of descentof 25 feetper second at0.85CL for the model as a low-wing shgle-en@e airplane. kl
max @
,, .,-
Fig. 16a NACA TN No. 1239
.
d-c
.:
. —-— . -\ \
1 .
\
.
+ .-
—-..
—.-
—. ..—. -
\\ — —
- -_ _ - . I“.,
Y .
---
I — —..,—NAT IONAL ADVISORY
CONMITTEE FOR AERONAUTICS
0+ .8 L? - 16 2.0 /?.4 2.8 3/?
LI’ft coeff~clenz!, CL
(a) Propeller off.
Figure 16. - Effect of flap deflection on the neutral-pointmodel as a low-wing airplane.
- ._
.—
.
-.
location of the -
NACA TN No. 1239 Fig. 16b
Jo
40
30
1’ I 11
f/Q~ Tal/ s)ot– ––– Af’@u7%Q/ Filled— — W7gle s/otleo’ Filled
Double sbtt~d Open
.
NATIONAL ADVISORY
COMMITTEE RX AERONAUTK$
0 .4 /.2 /.6 2.0 24 2.0 3.2
Lift coeffici en~ CL
(b) Propeller
Figure 16.-
windrnilling.
Continued.
—
Fig. 16c NACA TN No. 1239
60
/0
50-
/0
o
\\
\
\ \ ,
\-. ___ __
// \ . \
\/
/
/ \.
\
u f@ 7i7i/ dot I I--—— Meui%il Filled—— J/h /e slotted
fFllteit
Doti /e sloM Open
\>
. _ .?
\
\ , \
\l
1
~
NATIONAl ADVISORY
COMMITTEE FOR AERONAUTS
(c) Power on.
Figure 16. - Concluded.
I
i
*
-—
NACA TN No. 1239 Fig. 17a
c:
50
40
so
50
40
30
t+-
———— —Prope/le K off
‘— Prop e/ler windmiliing‘Power on
<
~ _ \\
<\
NATIONAL ADVISORY
J I I IOMMTTEE FORAERONAUTICS
o .4 .0 MTrim /ift co efficien ~,, C~h
(a) Flap neutral.
Figure 17. - Effect of power on neutral-point location of the rn~clel
.
as a low-wing airplane.
Fig. 17b NACA TN No. 1239
40
.
.-, __
--b.
H+——---PrOpe Iler oti
——Prope//er windmilling I
LPhwer on-— -- ._ -. -. ---
- %
\
NATIONAL ADVISORYCOMMITTEEFORAERONAUTICS
.4 .8 L2 /!6 2.0 2.4Trim lift c 0 effic ien t, C~h
(b) Single
Figure 17. -
slotted flap.
Continued.
-.
.
NACA TN No. 1239
.
Fig. 17c
.
.
20
50
“d I
‘------ P~opellep off .— ‘— Pi-opel/er wi’ndmihg
OWG!F on
I
—.- _ ——. ._
, NATIONAL ADVISORY
II t COMMITTEEFORAERONAUTICS t \ ! I..
/2 L6 2.0 2.4Trim lift co e ffic ieht ,
(c) Double slotted flap.
Figure 17. - Concluded.
2.$cL&
20
/0
o
-/0
-Zo
o
-
!
\
,
.— ---/
,8
flap——— .
MLdru/
—— &ngle slatted—
D&le 9/o&c7’
\--
/ ‘
\
1
NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS I
/2, 16,
Lift Coefficient
Figure ld. - Increments in neutral-point location due to power of
20I
, CL
the model
24● 28●
as a low-wing airplane.
1-m
I
6 v1
,, I. . -. . ..- . . . . .
NACA TN No. 1239.
‘a
. Fig. 19a
*
30— —
___ \-. __
l’YTFtt— l“”I .
I I I I I I I I i/0
Flap– –– –- heu.tral— — Single slotted— Double slotted
NATIONAL ADVISORYCOMMITTEE FM AEllONAUTKS
—. .—— . ——.— - —.- _
0 ,4 .8 /2 /6 a 24 28 “ -
Wn IIF+ coefficien~ CL~
(a) Propeller off.
Figure 19.- Effect of flap on various longitudinal-stability parameters. of the model as a low-wing airplane.
Fig. 19a cont. NACA TN No. 1239
’08
F/a——— — i?Neu ml—— Single slotted ●
Double slotted ..
— ._ _
~
\
,NATIONAL ADVISORY \
@M~lTTEE ~OS AERfUIAUTt$S
-.
.
.
.
*
*
NACA TN No. 1239 . Fig. 19a cone.
,8
o
(a) Concluded..
Figure 19.- Continued.
Fig. 19b NACA TN NO. 1239
.F)a
P–––– tVeurat— — Single s/otted
Double slotted
,
NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS
.
●
. —.
-.(b) Propeller windmilling.
Figure 19. - Continued. .
...
NACA TN No. 1239.
Fig. 19b cont.
Flap● – –– – – Neutral
——Sin /e slottedDouLe Slotted
.
.
.
.-
.
—
(b) Continued.
Figure 19. - Continued.
.—
cone. NACA TN NO. 1239
.8
,4
0
.4
0
-4
/ f— -— ——. —— ——
I I I I I I 1
Flap– – –– Neutral—— Single shtted
Double s/otted
’12
.8
\\% / /
—————————_—\ / ~/-
tNATIONAL ADVISORY
COMMITTSS FM AERONAUTICS
—
—.
●
.
(b) ConclucML
Figure 19. - Continued.
.
NACA TN No. 1239.
.
.
.
●
F/ap– – – – Neutral— — J/n /e s/offed
zDou /e sb~ted .—
W
s.~~%Q.
?. NATIONAL ADVISORY
su
COMHITTSE ~ AERONAUTICS.
.12~
i--
,08E 0 .4 .8 L2 l.0 2.0 2.4 /2%
Trim lift coefficient, CL ~
(c) Power on.
Figure 19.- Continued.
,Fig. 19c cont. NACA TN No. 1239
0
.
-. 7
-.3
Flap-——— Neutral—— Jhgle ~htt e d
OouD/e sJot tt?d
\
\
\
7_rI)n lift coeffjcjent, Cib
-.
-
.
—
I
.
.
(c) Continued.
Figure 19. - Continued.
.
.
.
TN No. 1239 Fig. 19cconc.
.
O & .8 /.2 /.6 2.0 2.4 2.8
Trim lift coefficient, CLb
(c) Concluded.
Fimme 19. - Concluded.
.- —
——“
NACA TN NO. 1239
.—.
u
i‘= A
.—— —-——
Propeller offWin ctmillingPower on
.12
-.08 f
.04
30
20
JO
o .4 /.2 . /.6
Trh] /ift coefficient, CLb
(a) Flap neutral; ~fl = 5f2 =
NATIONAL ADVISORYC.WH1?-TEEFc4 uRowJrKs.
OO.
,.
.-.
—
,
.
Figure 20. - Effect of power on various longitudinal-stabilityparameters of the model as a low-wing airplane.
.
.
●
✎
Fig. 20b NACA TN No. 1239
.3
— . . _ . — ——— ——
—. __x
8
NATIONAL ADVISORYCOMMITTEE FOR AERDNAUTKS
o & .8 I.z 1.6 2.0 2.4
Trim lift coefficient, CL b
(b) slotted flap; 6f2 = 30°.
Figure 20. - Continued.
.
.
.—
.—
.
.
.“
.
NACA TN No. 1239.
.
.8
o –––– P[opelk[ off— — Wmdmt}lmg
Power on
H
. I I—.———.—-—
I1 NATl~NAL ADVISORY
COMMITTEE FOR AERONAUTICS
o 4 .8 /.2 1.8
7Hm /ifl caefficienf, CLb
(a) Concluded.
Figure 20. - Continued.
/2
8
4
0
Fig. 20a cone.
h
.II
.
..
.
NACA TN No. 1239 Fig. 20b cone.
.
,
1.2
.8
.
.
0
B
o .4 .8 /.2 /.6 2.0 2A
77im lift coefficient, cLb
(b) Concluded.
Figure 20. - Continued.
Fig. 20C NACA TN NO. 1239
# \ >. I\ \. \
—————PYopeJler off— — Whdmillinq
[ [
+
I\
- h.-- =~
r
— —.——~ -N
1 1NATIONAL ADVISORY
CO~MITIEE RX AERONAUTS
●
L2 1.6 2,0 2.4 2.8 3.2 3,6
Trim lift coefficient, CLb
(c) Double slotted flap; ~fl = %2 = 20°.
.
“
.—.
—
-.
.
Figure 20. - Continued.
NACA TN No. 1239
.
.
.8
,4
-.
.
..
3
/
-.—— ——. -—- .—— .
-
r
—— -- — #?fopeller off— — pi;:rill:f
~ From surveys RI+
I
I ! I 1 I 1 1 , ,
I
I II I I I I1NATl&NAL ~DVISO&Y
COHMITTEE FIX AERONWTKS
Fig. 2(Ic cone.
/.2 1.6 2.0 2.4 2.8 3.2 3.6
Trim /i+?
(c)
I?iguxe
coefficient, cL~
Concluded.
20. - Concluded.
#
NACA TN NO 1239
.2
— ~\
\
—-. —- .— _ .— - .—
——_ __——
20. -
\10 If
~-—. ——-——-—-- ——
0
NATIONAI.ADVISORYCO!IMITTSS ~ AERONAUTICS
/0
-. _
i ‘
/
o # .8 /.2 j.6 2.~ 2.4 28
Trim lift coefficient, C~b
Figure 21.- Increments in longitudinal -stabfity parameters due topower of the model as a low-wing airplme.
.
..-.
—
.-
,
.- ----- —. -.
.
●
-.
-
No. 1239 Fig 21 COIIC.
.4
/ /
0$/“&%
-.4Flap Tail slot–––––Neural Fine d— — Single slo~ted FU)ed
Double slotted Open F#l
o f? .8 }.2 f.6 2,0 2.4 Z.8”
Trim lift coefficien~, CLb
—
.
Figure 21. - Concluded.
—
.—-- -.
k----’
\
‘~040-12162024
~cale, Inches
\ M,- . .,. ,
“’-%’>“Q;+I!6
(a) a = -8.9°; CL = 1.56; 6 inches rightof center line;Tc’ = 0.26.
~ Figure 22.- Contours ofdynamic-presswe ratios behind model as a 1OW-WQ airpbe with full-span
double slotted flap.bfl = 6f2 = 33°; tailoff;power on.
II
k. ●
11’ i,. : 1
.
. ●
b ,
$y7tWind
/-----L----- =:$-.”/
040121620”24Scale, Inches* LI
(b) a = -8.9°; CL = 1.56; 6 inches left of center line; Tc’ = 0.26.
Figure 22.- Contbkl.
%/w
- -G-- * ~Fuselage
&&g- -—&—— ..—-. ——.Thrust
24
“E>>~~Jg
“dLl_LLU04012162024
16-
Scale, inches
(c) a = -1.6°;CL = 2.30; G ~ches rightof center ~% Tc’ = o“~”
Figure 22.- Continued.
1,t
# ,
,!,1’’” :l,’ t iI I
------
#:I
Wind. u
L
1,9
ii~~Ill04812162024
5cule,lnches7- bL
UumlummP-’m~~
(d) a = -1.6°; CL = 2,36; 6 inches leftof center Hne; Tc’ = 0.36.
F@ure 22.- Conttiued.
1,
f
I
(yqt,
-. -.
/./
\
●
,~:1
.,, ,I
ki i
111[1 1 I I I04812162024
Scale, inchu
(e)
.
,,.
,.,I
a = 4.3°; CL 3:01; 6 inches right of center line; Tc’ = 0.49.
Figuqe 22. - Continued.
. 1 i:
%/?
Wind\ 1.1
‘—— --~_@ 5e/age a .
11111 I IE-
1 I ~u ,0481216~24
Sco Ie, inches
.MN’faw Amlmw
~m—
(f) a = 4.3°; CL = 3,01; 6 inches left of center line; Tc’ = 0.49.
Figuxe 22.- Concl~ed,
,, I
Wind
IIIIJ I I048121620Z4
.5cd/e, inches!LITUUU ~-
WIlm m ~=
.
(a) a = 1.35°;CL = 2.69; 6 inches rightof center Une; Tc’ = 0.44.
/
*qt *(J
Figure 23.- Contours of — behind model as a low-wing airplane with Ml-span double slottedq L flap. Bfl = 5f2 . 32°; tail off; power on.
.-
* ‘*
1
t
‘t
WindACL
\) ./
-3–.r .-
–:6
- --45
~ Fus elqe-——. —— .—. _Thrust ~C.Cj
—— —.— . -~
V!?2b>’>
——-= —
78
-4
1111 I I04812/62024
Scale, inches
,(I)) a = 1,35°; CL = 2.69; 6 Inches left of center tie; Tc’ = 0.44.
i,~’,, Figure 23.- Concluded,
,1
i’ ‘1
,1
,.
.-
(d:g)
Wind
/0“/2
,,. 04812162024Sccale, Inches (3
mTwul -.“ avnmmmmwlu
., ,,,
(a) a = -8.9°; CL = 1.56; 6 inches riglit of center line; Tc’ = 0.26,
Figure 24. - Contours of downwash angles behind model as a low-w@ airplane with full-spin dotile
slotted flap. 6f1 = 6f2 = 33°; tail o~ power on.
.
4 “.I
I :.
2!zp
,
e
kkg)Wind
Fuxlagg= - ~=-
04812162024Scale, Inches 676 *
NATW4M ADVISORY
CMm-rEE Fm mauuncS
(b) a= -8.9°; CL = 1.56; 6 inches left 01 center line;Tc’ = 0.26.
Figure 24.- Conthmed.
L
.-
.
.. ..—
,
Wind
.
— . —-. —---Q-?-hrut Q)+Cg. \
~
04812162024
12
Scale, inches 16
\
20 20 10
NATM U41&MY
-mIMlwulKs
(c) a = -1.6°; CL = 2.36; 6inches right ofcenterl.ine; Tc’ = 0.38.
Figure 24, - Continued.
,,1, .’ II ‘1 I I -- --f ‘, # *
#
Wind
,I
1
16
—.— -— . .—. —.— - /4
11111 t I I I
0481216.2024Scale, inchex
N4TIWIAL MwsOaYCuMm m KMwrKs
(d) a = -1.6°; CL = 2.36; 6 inches left of center line; Tc’ = 0.38.
Figure 24.- Continued.
i’#
.I
,,
.,,,,
NATIONAL ADVISORY
COMMITTEE FOR AERONAUTICS
II,
(e) cf=4.3°; CL = 3.01; tlinche srightofcentirfie; Tc’ =0.49.
Figure 24.- Continued.
I
1: II I
, ,
t ,9
—- . .- .————-----
,
“ &––.
k
ldM_iui0481216202+ 20’
Scale, inchesNATIONAL ADWSCflY
mwlTIE m AInmLmS
(f) a = 4.3°; CL = 3.01; 6 inches left of center line; TC1 = 0.49.
Figure 24,- Concluded.#
#
l“:
,.
IIi i ,’,,
1,,. )’
,
1
WindAu
\
,--
(’=.5-/
~ Fuse/ag~. .+___;=.=_- -— — - — -—. —- —~ <
t“ .
~
04-812162024~cale, inches
WmmA1. A%mmY
CcoMm m -Ic6
(a) a = 1.35°; CL = 2,69; 6 inches rightof center line; Tc’ = 0.44.
Figure 25. - Co?+tourS Of A ~/Aa
. ,
$: ~li--
behind model as a low-wing @lane with full-span double slottal flap. .
%1 = 8f~ = ~“; ~ off; Power on.
r‘!1
I !1
ot: I
WindAcx
Fu.sdaqe- -4~{w---=Q+-+ —— —it —-—–
11111 I04812162024
Scale, Inches
(b) a = 1.35°; CL = 2,69; 6 inches leftof center line;
F@ure 25.- Conclwkd.
.
Tc’ = 0.44.
I
Fig. 26a NACA TN NO. 1239
“’ FmtHtnt
“2-4*-4 7?,- FFF#
-Lo
-L 2 I
-24 -20 -/6 -/2 -e -4 0 4 8 iz
?Wl i?~@e of ot~ock, dt ) dt?g
(a) Slot filled.
Figure 26. - Aerodynamic characteristics of the isolated horizonk.1tail.
.
.
.-
--
.
.
.
NACA TN No. 1239 Fig. 26b
-.
.
.2
-/?8 -z+ -20 ?7iiI Jjk 3 c7&$&,& de$ 8 /z.
(b) Slot open.
Figure 26.- Continued.
.
Fig. 26c NACA TN No. 1239
t t t-l
-i2
-/4
CO~MITT~E Fq AERO~AUTICS
-24 -20 -/6’ -/2 -d -4 0 4 d /2 /g
(C) Comparison of the lift curves,
Figure 26. - Concluded.
.
.
. .
NACA TN No. 1239.
Fig. 27a
.
i’
.
.
.5
4
.3
:2
.1
0
/6
8
0
-8
El
f% y \6
W;)>4 - <5\
%Ul_n . \. . \. .
k
: y:)
A ‘500
NAT;ONAL ADVISORY
$.OW~EE FDS AERDSAUTKS
-.2
-./
o
(a) Propeller off.
Figure 27. - Effect of elevator deflection on the aerodynamic character-istics of the model as a low-wing airplane with flap neutral.it = -I. 3°; tail slot filled.
Fig. 27a cone. NACA TN NO. 1239
-hc11
.20
,/6
,12
.08
,04
.
NATIONAL ADVISORYCQMMITTEEFm AERONAUTICS.
Lift coefficient, CL
(a) Concluded.
Figure 27. - Continued.
. .
.
—
NACA TN No. 1239 Fig: 27b
m——-.1 1 1 1
I I I I
1
NATIONU ADVISORY
COMMITTEE FOA AERONAUTICSI I I 1 1 [ I I I I 1 I
< -,4 8 /2 A6L /’?f &&b/k~f , C&
(b) Propeller windmilling.
Figure 27.- Continued.
Fig. 27b cone. NACA TN No. 1239.
.
-.,20
,16
./2
,08
.04
0
74 0 .4 .8 /,2 /.6
Lift Coeffl’cient ~CL
(b) Concluded.
Figure 27. - Continued.
.
_—.
. .
I
NACA TN No. 1239 Fig. 27c
.-
.
.
.4
,3
.2
./
0
16
8
0
-8
o L.%co e8fficiet
Fig. 27c cone. NACA TN NO. 1239
m
?’4
QJm
c7
F
7
7
*0.
.
1.
&i
“.
n
i
..
.
●
NACA TN No. 1239 Fig. 28a
.
.3
.2
,1
0
-J
1 I I I I I I I 1
1-tTFr’d::-1
*#K
x=== e ~P
A
+ “ NATIONAL ADvISORYc@!NllTfE FM &ROllA~k=
o .+ .0 /.2 1.6 2.0 Et4
Liff coefficient, CL -.
(a) Propeller off.
Figure 28. - Effect of elevator deflection on the aerodynamic character-istics of the m~del as a low-wing airplane’ with a full-span slottedflap. 5f2 = 33 ; it = -1, 3°; tail slot filled.
Fig. 28aconc. NACA TN No. 1239
. .
—
1
. .
. I1
i
II
.
.
NACA TN No. 1239
o .4’ .8 1.6 2.0 2.+
Lift coefficient, CL.
(b) Propeller
Figuxe 28. -
windrnilling.
Continued.
7+
:3
-02
-.1
0
.4 .(.3 /.2 }s6 20 2.4
o-3
-6-9-20
(b) Concluded. NATIONAL ADVISORY
C(MUITTEE F(M AERONAUTICS.
Figure 28. - Continuedm
4
. . . . . . .-
NACA TN ,No. 1239 Fig. 28c
s-s=Ql--
-~
$!c)
2
.1
0
-al
I . , , , , A
tI
aA
/6
6
0
-8
cl
‘pNATIONAL ADVISORY
CDHMITTES FOR AERONAUTICS
.4 .8 i.2 ).6 2.0 2.4
L if f cue f ~ic ien G CL
0
J
2.8
%’cl
(c) Power on.
Figure 28. - Continued.
Fig. 28c cone. NACA TN NO. 1239.
a
o
1
“
NACA TN No. 1239 Fig. 29a
.1
0
63
00
Q ‘6
6/
NATIONAL AOVISORY
Conlwm? Rq AEnallfurlc$
08 1.2 2.8 3.2 3.6
Li f !6 coe%tc lcnz?, CL
(a) Propeller off.
Figure 29. - Effect of elevator deflection on the aerodynamic characteristics of the model as a low-wing airplane with full-span doublslotted flap. afl = 6f2 = W“; it = -1.3°; tail slot open.
.e
Fig. 29aconc. NACA TN No. 1239
9
I In-l
‘1 7 I I II
I
i I
a)
.
0:ni -a
1.
t%
0
23x
—
..
.
. , , ,flx # I-
8
.
.
c
No. 1239 Fig. 29b
—
1.2 20 2.4 28 3.2 3.6Lif}6coeff icieht, CL
(b) Propeller
Figure 29. -
windmilling.
Continued.
.
.20
,/6
./(?
,00
.04
0
Ibe
. (cieg)
-9 \ “-vL \
-b \
\
wo -e-- ~ ~
%+s
3
NATIONAL ADVISORYCOMMITTEEFORAERONAUTICS
>
/.6 2.0 2.4 2,8
Lift coefficient ~ CL
(b)
Fimre
Concludti.
29. - Continued.
3.2
,, .1
1 ●
. .
NACA TN No. 1239 Fig. 29cs
t’
6.—LJ.—
L
I
0 ‘6J
,6 1,2 L6 20 2,4 223 3,2 3.6Lift coefficient , CL
(c) Power on.
Figure 29. - Continued..
Fig. 29c cone. NACA TN No. 1239
..-
NACA TN ‘No. 1239 Fig. S
.
II I I I I
E#
r-t--l--r-l
I I I I I I I I 1 I T I 1 1 I
1.2 1.6 2.0 2.4 2.8 3.2 3.6 40
Lif + coefflc~ent, CL
Figure Xl. - Effect of stabilizer setting on the aerodynamic charac-teristics of the model as a low-wing airplane with full-span double
●
slotted flap. 6f1 = 30°; 6fz = ao; ae = OO; power on.
P (Illustrative pro&edure for obtaining data for determining qt/qand c .)
.—. -—
Fig. 32 NACA TN No. 1239
su-w-, ‘L,
[a)
cm
t
Tc=J- ,
Z/iiI
[b)
off
c’ ICLb
(t/.$)/ai
(d NATIONAL ADVISORYGOMMITTEE FORAERONAUTICS
Figure 32. - Vector diagrams used in deriving neutral-point equation.
r+
.*
Wind-TunnelInvestigationof the Effect ofPower and Flaps on the Static LongitudinalStabilityCharacteristicsof 8ingle-EngineIow-WingAirplane?fodel.ArthurR.Wallace, Peter FIRossi, and ““Evelyn G.Wells. April 1947
NACA TN “No. 1239 Fig. 33
.
#
?
Figure W.-
/.2 L6 2.0 2.4 Z8 3.2 3.6 40
Lif+ coefflcienf, CL
Effect of stabilizer setting on the aerodynamic charac -teristics of the model as a low-wir& airplane with full-span doubleslotted flap. afl = 30°; 6fz = W; 6 = OO; power on. “e
(Illustrative pro&dure for obtaining data for determining q#qand c .)
—.
Fig. 31a NACA TN No. 1239
I
a
_.. —3—
T
.#
.—-/4 -/. -I!o :8 ?6 -4 :2 0 .2 .4 .6 .8 [0 [2
c[~NATIONAL ADVISORY
COMMITTEE F~ ASSONAUTICS
(a) AcLt and CLt S
< *
Figure 31. - Chart for graphically determining the effective dymamic-pressure ratio and effective tail angle of attack from model tail-on, 3
tail-off, and isolated-tail data. The broken lines represent thefinal approximation for the sample solution of Table IV.
NACA
*AC~Vfi2
.9
.8
.7
.6
.5-
.4
.3
TN No. 1239 Fig. 31b
.
.6
%/~NATIONAL ADvISORY
CONMITTU! PW ARONAUltCS
(b) q@.
Figure 31.- Concluded.
,*. I
1.0 1.2 14 1.6 1.8 2.0 2.2 2.4
Fig. 32 NACA TN No. 1239
LVf=—+ ‘Lt
(d
c’ It c~b(kaij .fl
Tail off
(c) NATIONAL ADVISORYGOHMITTEE FOR AERONAUTICS
Figure 32. - Vector diagrams used in deriving neutral-point equation.
.—
I.—
