1、NASA TECHNICAL NOTEP_IZZNASA TN 0-5971COPyLONGITUDINAL AERODYNAMICCHARACTERISTICS OF A TWIN-TURBOFANSUBSONIC TRANSPORT WITH NACELLESMOUNTED UNDER THE WINGSby Francis J. CaponeLangley Research CenterHampton, Va. 23365NATIONALAERONAUTICSAND SPACEADMINISTRATION WASHINGTON,D. C. OCTOBER1970Provided by I
2、HSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1, Report No, 2, Government Accession No. 3, Recipients Catalog No.NASA TN D-59714, Title and SubtitleLONGITUDINAL AE
3、RODYNAMIC CHARACTERISTICS OF ATWIN-TURBOFAN SUBSONIC TRANSPORT WITH NACELLESMOUNTED UNDER THE WINGS7. Author(s)Francis J. Capone9. Performing Organization Name and AddressNASA Langley Research CenterHampton, Va. 2336512. Sponsoring Agency Name and AddressNational Aeronautics and Space Administration
4、Washington, D.C. 205465. Report DateOctober 19706. Performing Organization Code8. Performing Organization Report No.L-714110. Work Unit No.737-01-10-0311. Contract or Grant No13, Type of Report and Period CoveredTechnical Note14. Sponsoring Agency Code15. Supplementary Notes16. AbstractAn investigat
5、ion has been conducted in the Langley 16-foot transonic tunnel to deter-mine the longitudinal aerodynamic characteristics of a 0.062-scale, twin-turbofan subsonictransport at Mach numbers from 0.55 to 0.85 and angles of attack from about -2 to 6 .The Reynolds number based on wing mean aerodynamic ch
6、ord varied from 2.25 106 to2.70 106. The effects of model-component buildup, horizontal-tail effectiveness, boundary-layer transition, and wing and nacelle modifications were measured. The model was mountedby using a sting-strut arrangement with the strut entering the model through the underside oft
7、he fuselage approximately 65 percent of the fuselage length rearward of the model nose.Strut-interference effects were measured and applied as a correction to the data.t7. Key Words (Suggested by Author(s)Subsonic _erodynamicsSubsonic transportStrut interference18. Distribution StatementUnclassified
8、 - Unlimited19. Security Classif. (of this report) 20. Security Classif. (of this pagelUnclassified Unclassified21. No. of Pages93“For sale by the Clearinghouse for Federal Scientific and Technical InformationSpringfield, Virginia 2215122. Price“$3.00Provided by IHSNot for ResaleNo reproduction or n
9、etworking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-LONGITUDINAL AERODYNAMIC CHARACTERISTICS OFA TWIN-TURBOFAN SUBSONIC TRANSPORT WITHNACELLES MOUNTED UNDER THE WINGSBy Francis J. CaponeLangley Research Ce
10、nterSUMMARYAn investigation has been conducted in the Langley 16-foot transonic tunnel to deter-mine the longitudinal aerodynamic characteristics of a 0.062-scale, twin-turbofan sub-sonic transport at Mach numbers from 0.55 to 0.85 and angles of attack from about -2 to 6 . The engine nacelles were m
11、ounted under the wings. The Reynolds number basedon wing mean aerodynamic chord varied from 2.25 x 106 to 2.70 x 106 . The effects ofmodel-component buildup, horizontal-tail effectiveness, boundary-layer transition, andwing and nacelle modifications were measured. The model was mounted by using a st
12、ing-strut arrangement with the strut entering the model through the underside of the fuselageapproximately 65 percent of the fuselage length rearward of the model nose. Strut-interference effects were measured and applied as a correction to the data.For the small range of tail deflection (-0.5 to 0.
13、5o), there was little or no effect ofhorizontal-tail deflection on lift-curve slope, model stability, drag coefficient, or maxi-mum lift-drag ratio. The model with free boundary-layer transition had more lift at highangles of attack and less stability; and for tail deflections of 0 and 0.5 , the lif
14、t coeffi-cient at which pitchup instabilities occurred was higher than that for the model with fixedtransition. The configuration with a modified wing (reduced wing thickness ratio) andlonger nacelles had greater lift at the same angle of attack and a higher lift coefficient atwhich pitchup instabil
15、ities occurred than did the basic configuration. The drag-rise Machnumber for the modified configuration was increased by 0.02, and the modified config-uration had much less drag due to lift at the higher Mach numbers than that of the basicconfiguration.INTRODUCTIONThe National Aeronautics and Space
16、 Administration has conducted a wind-tunnelinvestigation to obtain data for a correlation between wind-tunnel and flight-test resultsfor a twin-turbofan, short-haul, subsonic transport with engines mounted under the wings.This airplane is capable of carrying about 100 passengers. This report present
17、s onlythe results of the wind-tunnel investigation.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The wind-tunnel investigation was conductedwith a 0.062-scale model in the Langley16-foot transonic tunnel at Machnumbersfrom 0.55to 0.85and anglesof a
18、ttack from -2oto about6. The Reynoldsnumber basedon wing meanaerodynamicchord varied from2.25 106to 2.70x 106. The effects of model-componentbuildup, horizontal-tail effec-tiveness, boundary-layer transition, andwing andnacelle modifications were measured.Subsonictransports are frequently designedwi
19、th fuselageaftersections that arenonsymmetrical with a large amountof upsweeponthe bottom of the afterbody. Thepressure drag onthis section of the fuselagecanbe a large part of the total fuselagedrag.A recent investigation as reported in reference 1 was concernedwith evaluatingthe sting-support inte
20、rference effects of a conventionalstraight sting that enteredthrough the rearof three subsonictransport models. However,the straight sting required a rather largecutoUtonthe afterbody of the fuselage.The model of the present investigation was mountedin the windtunnel by using asting-strut support ar
21、rangementwith the strut entering the modelthrough the undersideof the fuselageapproximately 65percent of the fuselage,length rearward of the modelnosewhich minimized alterations to the fuselage. Strut-support interference effectswere determined andapplied as a correction to the measuredaerodynamicch
22、aracteristics.SYMBOLSModel forces and momentsare referred to a stability axis system with the modelmomentreference center located 82.80centimeters rearward of the model nose corre-spondingto 22.4percent of the wing meanaerodynamicchord which is approximately atthe nominal center-of-gravity position
23、of the airplane. Dimensions are given in theInternational Systemof Units (SI).A aspectratiolocal wing chordwing or tail mean aerodynamicchord (Wing_ = 21.17 centimeters)CA,iCDCD,pnacelle internal axial-force coefficientdrag coefficient, DragqScomputed profile drag coefficientCD,min2minimum drag coef
24、ficientProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-CD,trim trim drag coefficientCL lift coefficient, LiftqSCL,M lift coefficient at CD,minCL,trim trim lift coefficient (lift coefficient at Cm = 0)CL_ lift-curve slope per degreeC m pitching-moment
25、 coefficient, Pitching momentqS_0CmCmc L static-longitudinal-stability parameter, OCLCm, o pitching-moment coefficient at zero liftZ_CD,HVaverage drag-coefficient increment due to strut interference,(CD)with strut- (CD)without strutdrag-coefficient increment due to adding horizontal and vertical tai
26、lsACm,avdrag-coefficient increment due to adding nacelle 1 and pylonaverage lift-coefficient increment due to strut interference,(CL)with strut-(CL)without strutaverage pitching-moment-coefficient increment due to strut interference,(Cm)with strut-(Cm)withoat strutdC Dk M drag-due-to-lift factor,d(C
27、L- CL,M) 2L/D lift-drag ratio(L/D)max maximum lift-drag ratio(L/D)tri m lift-drag ratio at trim conditionsM free-stream Much numberProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-q free-stream dynamicpressureR Reynoldsnumber per meterwing reference a
28、rea (3674.30centimeters2)TtX,ZOt w6hSubscripts:stagnation temperaturewing coordinateswing angle of attack (1 with respect to body center line)incidence angle of horizontal tail, positive when trailing edge is downl loweru upperAbbreviations:LER leading-edge radiusWL water lineModel- component design
29、ations:B fuselage plus wing-root-flap actuator fairingH horizontal tailN1N2Tbasic nacelle and pylonbasic nacelle and pylon with rear-end extensionwing trailing-edge-flap actuator fairings (two each located outboard on wing)V vertical tail4Provided by IHSNot for ResaleNo reproduction or networking pe
30、rmitted without license from IHS-,-,-W1W2W3basic wingbasic wing plus leading- andtrailing-edge chord extensionsbasic wing plus trailing-edge chord extensionAPPARATUSModelThe complete 0.062-scale basic model is shown in the sketch and photographs offigures 1 and 2, respectively. The model represented
31、 a twin-turbofan, short-haul, sub-sonic transport weighing about 45 000 kilograms that was capable of carrying about100 passengers at a cruise Mach number between 0.78 and 0.80. The design lift coeffi-cient is 0.30. Details of the various model components are presented in figure 3.Fuselage.- Fuselag
32、e geometry and cross sections are shown in figures 3(a) and 3(b),respectively. The fuselage was 171.19 centimeters long and had a fineness ratio of 6.9based on the maximum body depth. The wing root fairing was located between fuse-lage stations 54.33 and 109.76. A fairing on the fuselage used to hou
33、se a wing trailing-edge flap track and actuator mechanism extended from station 85.04 to 105.03. (Seefig. 3(b).) The wing trailing-edge flaps were not simulated during this investigation.Basic wing.- The planform geometry of the basic wing (Wl) is shown in figure 3(c).The basic wing had an aspect ra
34、tio of 8.41, a span of 175.59 centimeters, an incidenceangle of 1 , and a dihedral angle of 6 . Both the leading and trailing edges had discon-tinuous sweep. Airfoil ordinates for the basic wing are presented in table I(a). Themodel with the basic wing is shown in the photographs of figure 2.Two mod
35、ifications were made to the basic wing as shown in figure 3(d). The modi-fication for wing 2 (W2_ consisted of a 1-percent-chord leading-edge extension and a15-percent-chord trailing-edge extension, both outboard of span station 32.19 which wasthe spanwise location of the break in the leading and tr
36、ailing edges of the basic wing. Thetrailing edge also extended inboard to the nacelle pylon. Photographs of the model withthis wing are presented in figure 4. The modification for wing 3 (W3) involved only atrailing-edge extension from 15 percent chord at span station 32.19 to 0 percent chord atspan
37、 station 65.67. The model with this wing is shown in the photographs of figure 5.Airfoil ordinates for wings 2 and 3 are presented in table I(b). These ordinates were non-dimensionalized with respect to the local chords of wing 1. Therefore, these modifica-tions reduce the wing thickness ratio when
38、based on the chord of the modified wing. Forexample, at span station 32.19, the maximum wing thickness ratio for wing 1 (based on thechord of wing 1) is 0.108, and for wing 3 the maximum thickness ratio is 0.095 (based onProvided by IHSNot for ResaleNo reproduction or networking permitted without li
39、cense from IHS-,-,-the chord of wing 3). It shouldbenotedthat wings 2 and3 were tested with a differentnacelle from that onwing 1 andwithout the flap-track fairings onthe wings. The flap-track fairing at the wing root, however,was present.Only the complete modelusing wing 1 includedfairings onthe wi
40、ng for the wingflap tracks andactuators. A sketch of the fairings is presentedin figure 3(e). Thesefairings were located at spanstations 40.64and 56.82 and are shown in the photographsof figure 2.Nacelles.- Sketches of the two nacelles tested are presented in figure 3(f).Nacelle 1 (N1) was 34.54 cen
41、timeters long and was tested only with wing 1. Nacelle 2(N2) was similar to nacelle 1 except that the rear portion was extended 7.08 centimetersresulting in a total length of 41.62 centimeters. This nacelle was tested only with wings 2and 3. Both nacelle inlets had the same geometry and were located
42、 at the same bodystation.Horizontal and vertical tails.- Figures 3(g) and 3(h) show the planform geometryof the horizontal and vertical tails, respectively. Airfoil ordinates are presented intables H and III. The horizontal tail was all-movable with the hinge axis located at fuse-lage station 160.93
43、.Model Support SystemThe present investigation utilized a sting-strut mount in order to minimize thealterations made to the fuselage for a support system. A sketch showing the varioussupport systems is presented in figure 6. For determining the aerodynamic characteris-tics of the model, the model wa
44、s supported with the strut entering through the undersideof the fuselage at a location approximately 65 percent of the fuselage length to the rearof the nose as shown by the sting-strut arrangement of figure 6(a). This mounting sys-tem is also shown in the photographs of figures 2, 4, and 5. This ty
45、pe of strut allowedfor the minimum amount of cutout to the model (as compared with the large amount ofcutout to the models of ref. 1) since the strut chord length at the body juncture was about25.4 centimeters with a maximum thickness of about 2.54 centimeters.In order to assess the magnitude of the
46、 strut interference, two additional supportsystems were used as shown in figures 6(b), 6(c), and the photographs of figure 7. Fig-ures 6(b) and 7(a) show the model with the strut entering through the top of the model.A dummy sting strut was attached to the live sting strut through a blade downstream
47、 ofthe model base. The dummy strut entered through the bottom of the model (at the samelocation as the live strut). A positioning pin that was part of the dummy strut fit looselyinto the balance support block and was the only point of contact inside the model. Theloose fit of the pin allowed model d
48、eflection with the same aeroelastic support stiffnessas existed with only the live strut present. The support system of figures 6(c) and 7(b)Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-showsthe model with only the live strut entering through the top of the model (dummysting strut removed). The gapsbetweenthe struts andmodel were sealedwith syntheticspongerubber. Pressure inside the model was continuouslymonitored in order to detectandwarn of possible leakagethrough the seal if it occurred. Calibrations of normalforce, axial
