NASA NACA-TN-3961-1957 Effect of fuselage nose length and a canopy on the static longitudinal and lateral stability characteristics of 45 degrees sweptback airplane models having f.pdf

1、 .- .- .- _ a71 a15 a150 NATIONAL ADVISORY COMMITTEEFOR AERONAUTICSTECHNICAL NOTE 3961EFFECTS OF FUSELAGE NOSE LENGTH AND A CANOPY ON TEE STATICLONGITUDINAL AND LATERAL STABILITY CHARACTERISTICS OFWITH SQUARE CROSS SECTIONSBy Byron M. Jaquet and H. S. FletcherLangley Aeronautical LaboratoryLangley F

2、ield, Va.m-rmE-=-f- WasbingtonApril 1957Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSTECHNICALNO!D!3961IQ.9 EFFECTS OF FUSELAGE NOSE IXIThowever, at large sideslip sngles the canopyproduced some effect. W

3、ith approximately the ssme emount of directionalstability at sm angle of attack of 0 (obtainedby increasing the vertical-tail size in proportion to the fuselage size), an increase in the noselength caused large decreases, at moderate snd high angles of attack, inthe directional stahili of the comple

4、temodel however, positive incrementswereobtained only atthe angles of attack beyond the stall and at these anglesthe variation of with was much largerwith the wing on than a71with the wing off. At the lower angles of attack with the wing on, thevalues of thedata of figure 14.At mcderate and highangl

5、es of attack sn increaae in the fuselagenose length (fig. 14) resulted in large chsmges in the directional sta-bility of the campletemodel with the canopy on or off. The completemcxlelwith the shortest fuselages (fineness ratios of 7.41 and 8.34) andwithout the csnopy had directional stability throu

6、ghout the ae-of-attack range investigated. With the campy, however, there was somedegree.of directional testability in the high angle-of-attackrange forall mcdels. The completemodel with the longest fuselage became direc-tionally unstable esrlier than the other models (canopy on or off). Anincrease

7、in the directional instability of the wing-tielage combinationwith an increase in fuselage nose length for almost the entire angle-of-attack range (fig. 15), togeliherwith the rapid decrease with increasingangle of attack in the vertical-tail contribution to directional stability(fig. 16), accounts

8、for the rapid decreaae in directional stability of thecompletemodel with increasing angle of attack (fig. 14). At low lesof attack the instabil.i of the wing-fuselage ccnnbinationvaried linearlywith fuselage nose length. At high singlesof attack the longest wing-fuselage conibinationbecsme very unst

9、able (fig. 15), and, since there waslittle change in the tail contribution in this region (fig. 16), thisinstability accounts for the large smount.of instability for the ccxnpletemodel with the longest nose (fig. 14). b the low angle-of-attack rangethere is, of course, an increase in the vertical-ta

10、il contribution inas-much as the tail size was varied in proportion to the fuselage nose length;but, as mentioned previously, each tail contribution decreaaed withincreasing sngle of attack (fig. 16). Only the tail contribution for thelongest fuselage, however, decreased to zero and this occurred ab

11、ove thestall. When normalized with respect to the value of %B (for eachnose length) at CL= 0, little systematic effect of nose length is notedalthough the tail contribution for the longest nose length decreases morerapidly than the others at mciierateangles of attack. (See fig. 16.) Ifthe vertical t

12、ail spsn were held constant when the nose length was changed,instesd of being varied as WELSdone herefi a greater effect of nose lgthon the directional stabilitymight have been obtained owing to the relativelocation of the fuselage vortices with respect to the vertical tail.” Forthe present investig

13、ation,with the vertical-tail span being changed inproportion to the fuselqge nose length, the fuselage vortices would beexpected to rmain in essentially the ssme relative position with respectto the vertical ttil for all nose lengths. Jn figure 17 the tail contri-bution for each configuration csm be

14、 seen with respect to the wing-fuselagecmnbination and the completemodel. It should be noted that the data forthe wing-fuselage combinationwere obtained with the csnopy off only.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10 NACA TN 3961At sngles

15、 of attack beyond the stall the trends become erratic, prob-ably because of nonlinearities k the curves of the coefficientsplottedagainst angle of sideslip (see figs. 6(d) to 6(f), for exsmple); there-fore, caution should be exercised in the use of the stabilityderivativesin the high angle-of-attack

16、rge.The variation of-”Cn with 13 (fig. 6(f) was essentially linearfor angles of attack below the stall (about “) for the completemodelwith the shortest fuselage. At higher angles oflattack the curve of- Cnagainst P is nonlinear and at an mgle of attack of 32.70 directionalinstability as well sa the

17、nonlinearity occurred asmall angles of side-slip. An increase in the fuselage nose length (for.the completemcdel)resulted in a greater variation of Cn with , em increase in directionalinstability, and an earlier deperture of the curves.from LLnesrity.Effect of ceno .- For a given fuselage nose lWith

18、 the wing on the tailcontrib-uted positive directional stability for the entire aagle-of-attackrange,whereas with the wing off the tail contributionbecame zero at an angleof attack below-thestall. The favorable sidewash due to the addition.of the wing is in agreementwith theinvestigationof reference

19、 10 wherein,for a fuselsge with square cross sections, the addition of swept or unsweptwings in the low or high positions contributed favorable sidewash at thetail, the greatest amount of favorable sid-”Jaquet,Byron M., end Cowsn, Jo-W.: Effect-of Fuse-lage and Tail.Surfaces on Iaw-SpeedYawing Chara

20、cteristicsof aSwept-WingModel As Determined in Curved-FlowTest Section of LangleyStability Tunnel. NACA TN 2483, 1951. (SupersedesNACARML8G13. )._u.6. Silverstein,Abe, end White, Jsmes A.: Wind-Tunnel InterferenceWithParticularReference to Off-Center Positions of the Wing sxulto theDownwash at the T

21、ail. NACA Rep. 547, 1936.7. GilliE!,Clarence L., Polhsmus, lMwardCharts for Determining Jet-Boundaryin 7- by 10-Foot Closed Rectangular1945. (FormerlyNACAARRL5G31. )8. Queijo, M. J., snd Riley, Donald R:and Resulting Stability Derivativesc and Gfisy,Joseph L., Jr.:”C%.l .252.0% .0.0976171.5Z5.409.26

22、2r2.79a.428.368.7%.59.818.767.:;0.665A, and vlth45 .weptbackwingmodelwith squarecrom fiec-antloff: B = OO,a wing-fuselagecodination having a fuselagewith squarecrossBectionsand.a low - ofaapectratio 3. Canopyoff; = OO.Lfm;-, and with a forProvided by IHSNot for ResaleNo reproduction or networking pe

23、rmitted without license from IHS-,-,-(a) vhtion d CLFigure6.- Effect of canopy and fuselage nose lengthwith angle of sideslipfor a complete,. , -m40%5-m 45-lo-50510 IS 20 25(e)Variationof C with f).Figure6.- conthmed., InJma71Provided by IHSNot for ResaleNo reproduction or networking permitted witho

24、ut license from IHS-,-,-,.c1(f)AE,d csmopy on andOffj = OO.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, , #(a)ti-p,w- - .-Variationof aud with 13.%(b)Variationof C; and with $.Figure8.- Aeronsmic characteristics in sideslip of a complete 45 sweptbackwingmxlel hambgabhmt nose, a finenessratioof 8.71.,and a ratio of fuselage nose length to maximum depthof 5.C9. Campy on and off. %Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-