NASA NACA-RB-3L02-1943 Proposal for a propeller side-force factor《对螺旋桨偏航分力的建议》.pdf
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1、.RB No. WX)2(If, - , .,.(,“-).4 *“-NATIONAL ADVISORY cOMMlmE FOR AERONAUTICwilmm IuwolrrORKWALLY ISSWDDecenber 1943 asRestricted Bulletin 3L02 .PROPOSAL FOR A PROPELLER SIDE-FCIRCEFACIWRBy Herbert S. R$tmerLangley Memorial Aeronautical LaboratoryLangley Field, Va. .WASHINGTONNACA WARTDLIEREPORTS are
2、reprintsofpapersoriginallyissuedtaproviderapiddistributionofadvanceresesmhresultstoanauthorizedgrouprequiringthemforthewareffort.Theywerepre-viouslyheldunderasecuritystatusbutarenowunckssified.Someofthesereportswerenottech-nicallyedited.Allhavebeenreproducedwithoutchangeinordertoexpeditegeneraldistr
3、ibution.,IL- 336Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.3 1176013542692 !NATIONAL ADVISORY COMif15!KEEFORR3LSTRICT31D BULLETINAERONAUTICSPROPOSA% l?OR A PROPELLER SIDE-FORCE FACTORBy Herbert S. RihnerSUMMARYfKnowledge of the side force on a
4、proeller in yaw -the fin effect - is ueful in the design of tail sur-faces , in the testing of pawerecl.aircraft models, and iiq iornal. stability and control analyses. A side-forcefactr coinputed from the plan form and pitch distribution in shown to Oe a good index of the relative effec-tiveness, N
5、er blade, of yaved propeller in developingside force. By the general use of sideforce factors,existing charts of prpeller side force may be simplyextrajolated to”give Me side force on any specifiedpropeller in any specified operating condition. Thesugestion is made that propeller manufacturers andde
6、signers present the stale-force factor with the activ-ity factor as a fundamental parameter for all bladedesigns and that reports of testsof powered models invrind tunnels include the sioo sind (): (1)0.2side-force factorblade sectiou chord at any radius rpzoyeller diameterblade angle at radius r(.0
7、when 13= 2a at.:. 4. :/0175R and p/Dtan=)m :,radius to tipeometric pitch at radius rThis side-force factor expresses the relative effective-ness, per blade, of a propeller in developing side forcein yaw or “noraal for ce in qitch and nay be used in comparing these characteristics of propellers. It i
8、s seento-3e similar to the activity factor I. .*Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3A.F. = 10;OO .;” + ($)3 ).i+liidhis intended to express the relative effectiveness,per blade, of a propeller in a%sorling power. .References 1 and 2 show
9、 that the side force on apropeller in yaw is approximately proportional to theprojected side area. There is a small correction foraspect ratio. Examination of equation (1) will showthat the proposed sideforce factor is directly proportioaal to the projected side area of one blade;l thecontant of pro
10、portinality is chosen to give a valueof the order .of the activity factor (6O to 140) as aconvenient magnitude. The sideforce factor is there-fore a suitable criterion for comparing propellers havi-ng the same number of blades.USE ,OF SIII this information has been used to prepare thecharts presente
11、d herein as figures 1 and 2. Figure 1gives the ratio of stale-force derivativesoyj/ for desired propellerCys$ for Hamilton Standard propeller 3155-6as a function of the side-force factor for the desiredpropeller; figure s22gives the ratio of side-force deriva-tivesCy$ for desired propeller1CY% for N
12、ACA propeller 1-3062045. .,. .,.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-5,./as a function of the side-force factor for the desiredpropeller. In both figures 1 and 2, the approximaterelation of equation (2) is plotted foq comparison.For a four
13、-%lade single-rotating propeller , for example,figure 1 may be applied as follows: The ratioEY$ for desired fourblade propellerCf SW for fourblade Hamilton Standard propeller 3155-6is thb ordinate on the fourllade curve corresponding tothe abscissa S.F.I?. for desired propeller.khb + curve for a spe
14、cified propeller may apply tothe angle to the zerolift chord; whereas P g-enerallyapplies to the angle to the reference chord. Hence, the.,label i3= 25 Pat 0.75R on.a given curve does notm/11necessarily mean that the formula tan P = n:wouldgive the same value of at 0.75R. Zither definitionwill resul
15、t in approximately the same sise-force factorprovidod that, by ths same definition, = 25 at0.75R. A suitable procedure is to select any availabloPcurve and to computes curve ofn P against r/R from “JJthe relation p/Dtan=Ffail to pass through 25 atcurve is obtained by addingvalues of the incrementr/R
16、 = 0.75.This curve will generallyr/R = 0.75. The desiredor subtracting from all thethat will make = 25 atThe fact that the Hamilton Standard propeller 51556has Clark Y blade sections and the NACA propellerZCX3062-045 hae” NACA 16serias blade sections is of somesignificance. The charts of Hamilton St
17、andal*d propeller3155-6 should be used as the basis of extrapolation forpropellers having Clark Y or EM? 6 blade sections, andthe charts of NACA propeller 10-306045 should be usedas the basis of extrapolation for propellers having NACA16-series sections. This restriction eliminates errorsof the orde
18、r of 5 percent.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. . . -. .-:. -6.The significance of the blade section lies in thedifference in angle “between the reference chord and thezerolift chord for the several sections. This differ-ence is of t
19、he order of 3 to 7for the Clark Y and1 to 20 for the NACA 16-seriesRAF 6 sections and l%sections. The zerolift chord is fundamental in theevaluation of side force but blad-setting designationsgenerally refer to the geometric reference chord. .Thisconvention was retained in the side-force charts of r
20、ef-ermce 2. The curve for Hamilton Standard propeller3155-6 designated P = 25 at 0.753 thus nay also ?)edesignated PO = 28.2 at 0.75R, where 130 is theblade angle tb the zerolift- chord; the correspondingcurvo for iiACA propeller 10-3062-045 may be designated,PC)= 26.8 zt 0.75R. For accuracy, theref
21、ore, comparisonshould be made of propellers for which the average dif-ferpnco “etweon and 130 is nearly tho same; that is,propollers with more orless similar llede sectionsshbuld be compared.- ILLUSl?RA.TIV3 EULiPLEiZs an:. illustrative check, the side-force factorwill be used to obtain a value of t
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