1、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA Technical Memorandum 78650 Wind-Tunnel Results for an Improved 21-Percent-Thick Low-Speed Airfoil Section Robert J. McGhee and William D. Bea.sIey Langlq, Rewrcb Center Hanrptoori, Virginia Nationa
2、l Aeronautics and Space Administration satenmcandTl homver, at a lift aceffioiant of 1.0 (fig. 5(b) a deoFease of about 0.100 is sbom. Based on these thsoretioal wsults the desired deem in separation would be egpeated for the modified airfoil. The maximum Uft coeffioients for the airfoils aould not
3、be detarmined from the theary because the present methods cannot properly treat the flow field the orifices were located 8 tube diam- eters from the tip of the tube in the measurement plane of the total-pressure tubes. Each static-pressure tube had 4 Provided by IHSNot for ResaleNo reproduction or n
4、etworking permitted without license from IHS-,-,-The static pressures on the airfoil surfaces and the wake rake presaurea YBW maswed by 811 automatic pmssure-sc3anning system using variable-capacitanu8 pmcisian transducers. quartz manometers. shaft encoder operated by a pinion gear and rack attached
5、 to the circular model attachment plates. urn recoMed on magnetic tape. kic tunnel pre8sures yere maaswed vitb preoision Angle of attack was meas these corrections have not bsen applied to the data. PMSENTATIObl OF RESULTS The asults of this investigation have been reduced to coefficlant form and ar
6、e presented in the following figures: FU Effect of Reynolds number on seoticm characteristics for Effect of free-stream Haah tnrmber an seation characteristics for Comparison of section charactaristios for LS(11-0421 and Effect of Reynolds number on Aordwise pressure distribu ions far ComparFson of
7、chordvise pressure dhtributiom far I5(1)-0421 and LS(1)-0421 modified airfoil . 8 IS(1)-0421 dified airfoil . 9 LS(1)-0421 mwlified airfoilR . 10 Lds(1)-0421 modified airfoil . 11 Ls(I)-w21 modified airfoil8 . 12 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license
8、from IHS-,-,-Figura Variation of laaximum 1lft coefficient with Reynolds number for Variation of lift-drag ratio vith lift coefficient for IS(l)-0421 and LS(1)4+21 Mified airfoils . . . . . . . . . . . . 13 LS(1)-+21 and LS(1)-0421 this increase decambers the airfoil. (R = 9.0 x 106) for separation
9、of about 0.0 u for the LS 11-0421 airfoil as the ReynoZds number is are indicated by the comparison of figure 12(a) The seation data for the as the Reynolds number is decreased from 9.0 x 106 to 4.0 x 106, a = 00 A comparison of figures 12(b) (R = 4.0 x lo6) and 12(f) (1 = 40 shows a decrease In upp
10、er-surface trailing-edge hareasad fmm 4.0 x 10 2 to 9.0 x 10 b . Seotion Charaoteristics The seation charaateristics f r both airfoils are compared in figure 10 for Reynolds numbers from 2.0 x 10 8 to 9.0 x lo6. For the test Reynolds number 6 Provided by IHSNot for ResaleNo reproduction or networkin
11、g permitted without license from IHS-,-,-range, the modlfled airfoil displays a higtrer lift-ourve slope, a more linear lift owe, and an Improvement Fn maximum lift-drag ratio (fig. 14). This result is attributed to reduced upper-surface separation for the modified air- foil. Far a Reynolds number o
12、f 4.0 x IO6 (fig. 14) (i/d)- is PFam do to 85 far the modified airfoil. Thls value of (i/d)- far the modified airfoil coprpares favorably with the value for the ll-psrcant-tduak hee, Robart J.; and Beasley, Uilliam D.: Effects of Thickness on the Aerodynamic Characteristics of an Initial LowSpeed Fa
13、mily of Airfoils for General Aviation Applicatians. NASA M X-72843, 1976. 2. Smetana, Frederick, 0.; Sumey, Delbert C.; Smith, Neil1 S.; and Carden, Ronald K.: Ligfit Alrcraft Lift, Drag, and Moment Prediction - A Review ad BnalySiS. NASA CR-2523, 1975. 3. Bauer, Frances; Garabedlan, Paul; Korn, Dav
14、id; and Jameson, Antony: Supercritical Ying Sections 11. and kthematical Systems, Springer-Verlag, 1975. Volume 108 of Lecture Notes in Economics 4. Von Doenhoff, Albert E.; and Abbott, Frmk T., Jr.: The Langley Two- DtmAnsicmal Law-Turbulanoe Pressure Tunnel. NACA 1283, 1947. 5. Braslow, Albert L;
15、and box, Eugene C.: Simplified Hethod for Determination of Critical Height of Distributed Roughness Particles for Boundary-Layer Transition at Mach Wers From 0 to 5. NACA TN 4363, 1958. 6. Pankhurst, R. C.; and Holder, D. W.: Uind-Tunnel Twhnique. Sir Isaao Pitman and Sons, Ltd. (London), 1965. 7. P
16、ope, Alan; and Harper, John J.: Law-Speed Wind Tunnel Testing. John Uiley L Sons, ho., c. 1966. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABU I.- LS(1)-0421 AIRFOIL COORDlJZBTES x/c 0 .ooooo .00200 .00500 .O 1250 .02500 .03750 .05000 07500 .lo
17、o00 .12500 .15000 .17500 .20000 .22500 .25000 .27500 .30000 -32500 ,35000 ,37500 .40000 .42500 .45000 .47500 ,50000 .52500 .55000 .57500 ,60000 .62500 .65000 ,67500 ,70000 ,72500 ,75000 77500 .8OOOC .a2500 .a5000 ,87500 ,30000 .92500 ,95000 .97500 1.00000 0,00000 .01560 ,02380 .03600 ,04910 .05850 .
18、06610 .07770 .08660 .09390 .09990 .lo510 .lo940 .11320 . 1 1620 .11860 .12070 .12240 ,12340 .12410 .12440 ,12420 ,12360 .12270 .I2110 .I1910 .11660 . 1 1340 .lo970 .lo530 .lo030 .09470 ,08860 .08220 .07530 .OS810 .06070 ,05320 ,04550 03770 .03000 .02230 .01480 .00730 .00020 0.30000 -. 01070 -.01770
19、-. 02650 -. 03520 -, 041 40 -. 04650 -.05460 -.06100 -. 06610 -.07040 -. 07390 -. 07690 -. 07940 -.08130 -. 08260 -. 08380 -. 08440 -. Oe480 - .08470 -. 08450 - .OS380 -. 08290 -.08150 -. 07970 - -07730 - .07450 -. 07100 -. 06700 - 06250 -e 05750 -. 05230 -. 04680 -. 04120 -. 03550 -. 03000 -.02460
20、-.01950 -. 0 1500 -.01110 -.00810 -, 00600 -. 00520 -. 00590 -, 00890 ORIGINAL PAGE IS OF PooR QUALITY 9 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE E.- fS(1)-0421 HOD AIRFOIL CoORDIUTgs x/c 0,00000 .00200 ,00500 .01250 .02500 ,03750 ,05000
21、 .07500 .10000 .12500 ,15000 .17500 .20000 .22500 ,25000 .27500 .30000 .32500 .35000 .37500 ,40000 .42500 .45000 .47500 .50000 .52500 .55000 ,57500 ,60000 .62500 ,65000 .67500 .70000 ,72500 .75000 .77500 .00000 .82500 ,85000 .87500 .90000 ,92500 ,95000 97500 1 .ooooo ( zc upper 0.00000 ,01560 .02430
22、 .05400 .06510 .08650 .bo0 .lo340 .lo930 .11410 .11790 .I2080 .12290 .12430 .12500 .12500 ,12443 .12330 .12170 ,11960 ,11700 . 1 1400 ,10680 .lo270 ,09830 .09360 ,08860 .08330 ,07780 .07210 .Ob620 ,06010 .04760 .04120 .03480 .02840 .02200 .01Eb0 .009lO .00250 -. W420 .03830 .07360 .I i 060 05390 0.0
23、0000 -. 01 070 -. 01770 - -02650 -. 03520 -. 041 60 -. 04680 - -05500 -.Ob140 -.Ob650 -. 07070 -.07410 -. 07700 - -07940 -.08130 - -08280 -. 08390 -. 08460 -. 08490 - .08490 -.08460 - .0839O -. 08280 - -08130 -. 07940 - -07700 -. 07400 - .07050 -.06660 - -06230 -. 05760 - -05250 -. 04720 - 04180 -.0
24、3640 -. 03100 -. 02560 - .02060 -.01590 -. 00860 - ,00700 -4 00690 -, 00880 -. 01 320 -.oil80 10 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I I! d I Yo! i 1 +? i 11 Provided by IHSNot for ResaleNo reproduction or networking permitted without lic
25、ense from IHS-,-,-x/c Figure 2.- Comparison of mzan thickness distributions and camber lines for LS(1)-0421 and LS(1)-0421 modified airfoils. 12 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.64 .a .32 . I6 d2 dl - 0 -. 16 -. 32 -.a I I I I I 1- 0
26、.2 .4 .6 XlC .a I. 0 Figure 3.- Chordwise distribution of slopes. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-0 1 0- o Experiment - Theory (ref. 2) - Theory (ref. 3) 0 1 1 1 1 1 1 0 0 0 Figure 4.- Comparison of experimental and theoretical sectio
27、n data for LS(1)-0421 airfoil. M = 0.15; R = 4.0 x 106; roughness on. 14 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I 0 I Ai rfoi I r 1 I I 1 0 .2 .4 .6 .8 1.0 XI c (a) cl = 0.40. Figure 5.- Theoretical chordwise pressure distributions for R = 4
28、.0 x 10 6 . 15 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 -I 0 I I 1 1 1 I 0 e2 .4 e6 .8 1.0 Xl c (b) C, = 1.0. Figure 5.- Concluded. 16 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TmI side
29、 walls /- Diam.= I .67c - d Airflow “7 L oc End view ,section A-A Figure 6.- Typical airfoil model mounted in wind tunnel. c = 61 cm (24 In. ), 17 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Stohc-ptasuP6 I 1 Airflow I_) TU- - - - -i 4-7 -+ 1 -3
30、.042c 1. - - Figure 7.- Yake survey rake. c = 61 om (24 In.). 18 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-0 W 0 X 0 cu II P; n a - v Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-0 - I 8 8 W
31、- 5 s CD :- 0 II . m K 20 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-21 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-22 Provided by IHSNot for ResaleNo reproduction or networking permitted wit
32、hout license from IHS-,-,-L 0 e, 23 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-s i . ,_._-*_. -*- 0 N (D . N 0 W s X 0 (u n 5 v n 1.- 24 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-E 0 8 U o
33、0 F X 0 3 II p: n P U I 0 c Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a P, -0 a 20 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-o 0 X 0 Q, u P; F U 0 U 3 4 0 C 0 u I 0 c 0 U m a- 27 Provided
34、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-28 cd -.o 2 3 -0120 .Y16 -012q .a55 .01w 1.239 .0198 1.361 -0290 =In - - 06q 1 - -0751 - -079f - -07LAC - -07qZ Figure 11.- Effect of Reynolds namber on chordwise pressure distribution3 for Ls()-0421 modified airfoil. H = 0.15; roughness on. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
