1、ilo NATIONAL ADVISORY COMMITTEEFOR AERONAUTICSTECHNICAL NOTE 3547NOV ! 4 jg_AERODYNAMIC CHARACTERISTICS OF A SMALL-SCALE SHROUDEDPROPELLER AT ANGLES OF ATTACK FROM 0 TO 90By Lysle P. ParlettLangley Aeronautical LaboratoryLangley Field, Va.ItW as hingt onNovember 1955Provided by IHSNot for ResaleNo r
2、eproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSTECHNICAL NOTE 354AERODYNAMIC CHARACTERISTICS OF A SMALL-SCALE SHROUDEDPROPELLER AT ANGLES OF
3、ATTACK FROM 0 TO 90By Lysle P. ParlettSUMMARYAn investigation has been made to determine the effects of airspeedand angle of attack on the lift, drag, and pitching moment of a shrouded-propeller model, having a shroud length of about two-thirds the pro-peller diameter, over an angle-of-attack range
4、from 0 to 90. Testswere made of the complete model with the propeller operating and alsoof the shroud and motor combination with the propeller removed. Theeffect of inlet-lip cross-sectional radius on the static-thrust charac-teristics was also studied. These tests were made in connection withthe de
5、sign of a vertical-take-off free-flight model and the results arepresented herein without analysis as it is felt that they may be usefulin the design or analysis of other aircraft.INTRODUCTIONConsiderable interest has been shown recently in two types of ver-tically rising aircraft which utilize a sh
6、rouded propeller. The firstof these types is termed the coleopter (refs. i and 2). The second isa small, simple, one-man vertically rising aircraft which is littlemore than an engine-driven shrouded propeller. This aircraft is oper-ated by a man standing on a platform above the propeller. Flight-tes
7、tresults for research vehicles tested in the development of this generaltype of aircraft are presented in references 3 to 6. Additional infor-mation on shrouded propellers is needed for use in evaluating proposalsfor the coleopter and stand-on aircraft.The Langley Free-Flight Tunnel Section has in r
8、ecent flight testsgathered a limited amount of flight data on stability and control of ascale model of a shrouded-propeller stand-on vertically rising aircraftas reported in reference 5. It was felt, however, that, before thisresearch was extended to full-scale aircraft, force-test data were neededf
9、or a more detailed study of longitudinal stability and trim. Conse-quently, a series of force tests were performed to determine the effectsof airspeed and angle of attack on the lift, drag, and pitching-momentProvided by IHSNot for ResaleNo reproduction or networking permitted without license from I
10、HS-,-,-2 NACA TN 3547characteristics of a shrouded-propeller model over an angle-of-attackrange from 0 to 90o . The effect of inlet-lip cross-sectional radiuson the static-thrust characteristics was also studied. It was feltthat the results of these tests would be of assistance in the design oranaly
11、sis of other aircraft with shrouded propellers or ring wings. Thispaper presents these data without analysis.SYMBOLSCdSVPqLDMo/4CLCDCmc/4CTCpchord (axial length of shroud without inlet lip), ftshroud internal diameter, ftprojected side area of shroud, cd, sq ftangle of attack, degairspeed, ft/secair
12、 density, slugs/cu ftdynamic pressure, DV2/2, ib/sq ftlift, ibdrag, ibpitching moment referred to quarter-chord line, ft-lblift coefficient, L/qSdrag coefficient, D/qSpitching-moment coefficient referred to quarter-chord line, Mc/4/qScc 3/2static-thrust efficiency, wl/2Cpthrust coefficient, T/pn2Dp
13、4power coefficient, P/pnSDp 5Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN 354# 3TPQnDpstatic thrust, ibpower, 2_Qn, ft-lb/sectorque, ft-lbpropeller rotational speed, rpspropeller diameter, ftAPPARATUS AND TESTSA sketch of the model is shown
14、 in figure i. The basic model had ashroud 18 inches in internal diameter and 12.25 inches long which wasmade of glass fiber and plastic. A two-blade propeller, turned by a 5-horsepower variable-frequency electric motor, was located midway alongthe shroud. The clearance between the propeller tip and
15、the shroudwas 0.06 inch. Interchangeable inlet lips with cross-sectional diametersof 0.50, 1.00, 1.50, 2.00, and 3.00 inches were provided for the shroud.The tests were performed in the Langley free-flight tunnel whichhas a 12-foot octagonal test section. Inasmuch as the model was verysmall in propo
16、rtion to the size of the tunnel, no blockage or jet bound-ary corrections have been applied to the data. Tests simulating theforward-flight condition were made with the propeller set at a bladeangle of 8 at the three-quarters-radius station and rotating 6,000 rev-olutions per minute. The 0.50-inch-d
17、iameter lip was used in all the testsexcept those for static thrust. The angle of attack was varied from 0(thrust axis parallel to the airstream) to 90o in i0 increments. Tunnelairspeed was varied from 0 to 56 feet per second in increments of about7 feet per second. One test was performed over the s
18、ame angle-of-attackrange with the propeller removed at a constant tunnel speed of 56 feetper second.Static-thrust tests, using each of the several inlet lips, were con-ducted over a range of model propeller speeds from 6,000 to 10,500 rev-olutions per minute in increments of 1,500 revolutions per mi
19、nute. Thesestatic-thrust tests were made with the model thrust axis parallel to thetunnel axis in order to avoid the scatter in data caused by recirculationof the propeller slipstream when tests are run with the model crosswisein the tunnel.Provided by IHSNot for ResaleNo reproduction or networking
20、permitted without license from IHS-,-,-4 NACATN 3547RESULTSThe results of the forward-flight tests are presented in figures 2to 6. Since the propeller-off tests are intended to give someinfor-mation on the coleopter configuration without a propeller, the data arepresented in figure 2 as conventional
21、 coefficients based on forward speedin order that they maybe used for comparisons with other wings. Theresults of the tests for the propeller-on configuration are plotted asfunctions of both _ and V and are referred to both wind and bodyaxes in figures 3 to 6. These results are in dimensional terms
22、becausethe conventional coefficients becomeinadequate when the free-streamvelocity is zero, and there is no apparent advantage to using unfamil-iar coefficients.The results of the static-thrust tests presented in figure 7 indi-cate that efficiency increases with i_creasing lip cross-sectional diam-e
23、ter. As data for these tests were characterized by considerable scatter,the plots are the results of averaging data from several runs at eachtest point. The scatter was due primarily to the difficulty encounteredin measuring accurately the small momentsrepresenting motor torque andto the fluctuation
24、s in torque caused by the randomrecirculation of airin the tunnel test section.CONCLUDINGREMARKSAn investigation has been made to determine the effects of airspeedand angle of attack on the lift, drag, and pitching moment of a shrouded-propeller model over an angle-of-attack range from 0 to 90 . Tes
25、tswere made of the complete model with the propeller operating and alsoof the shroud and motor combination with the propeller removed. Theresults of static-thrust tests indicate that efficiency increases withincreasing lip cross-sectional diameter. Inasmuch as these tests weremade in connection with
26、 the design of a vertical-take-off free-fllghtmodel, the results are presented without analysis as it is felt thatthey may be useful in the design of other aircraft.Langley Aeronautical Laboratory,National Advisory Committee for Aeronautics,Langley Field, Va., August 30, 1955.Provided by IHSNot for
27、ResaleNo reproduction or networking permitted without license from IHS-,-,-NACATN 3547 5REFERENCES1. Von Zborowski, Helmut: The Coleopter. A Formula for Economy.Interavla, vol. X, no. i, 1955, PP. 29-55.2. Oestnich, Hermann: S.N.E.C.M.A. and the Coleopter. Interavia,vol. X, no. l, 1955, PP. 35-58.3.
28、 Zimmerman, C. H., Hill, Paul R., and Kennedy, T. L.: PreliminaryExperimental Investigation of the Flight of a Person Supported bya Jet Thrust Device Attached to His Feet. NACA RM L52DIO, 1953.4. Hill, Paul R., and Kennedy, T.L.: Flight Tests of a Man Standing ona Platform Supported by a Teetering R
29、otor. NACARM L54B12a, 1954.5. McKinney, Marion 0., and Parlett, Lysle P.: Flight Tests of a0.4-Scale Model of a Stand-On Type of Vertically Rising Aircraft.NACA RM L54B16b, 1954.6. Anon.: Hiller Shows Off Flying Platform. Aviation Week, vol. 62,no. 16, Apr. 18, 1955, P. 15.Provided by IHSNot for Res
30、aleNo reproduction or networking permitted without license from IHS-,-,-6 NACATN 3547_- Inlet- hp d_metert 18.0625 aurolumm strut-.5oo 4 _-Sec_on A- A 0 6InchesFigure i.- Sketch of model. All dimensions a_c in inches.Provided by IHSNot for ResaleNo reproduction or networking permitted without licens
31、e from IHS-,-,-NACA _ 5547 74Cmc_ 04_41612CD .8.4C/01.61.2.8.4/fY/_ -.-40 I0 20 30 40 50 60 70 80 90a, degFigure 2.- Variation of lift, drag, and pitching-moment coefficients withangle of attack. Propeller off inlet-lip diameter, 0.50 inch.Provided by IHSNot for ResaleNo reproduction or networking p
32、ermitted without license from IHS-,-,-8 NACA T_ 3547.8XD_4EO0Ec-ooC16128x_4c0-4-81612_8J40-47(_5 ft/sec -./il0 I0 20t 15Ot-:2 r- 1- -z%-,-i-: _Z_J 4 _-_1 f q- _._ ! EJ- I _,.A_:-$ -h“_, , i_T_,r,o140 50 60 70 80 90e,degFi inlet-lipdiameter, 0.50 inch; ptching moment referred to quarter chord.Provide
33、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA TN 5547 9.8_Qr-EoOEc_-4,I-el._-84jO_o_ -4c“-“0_-8c-3-122O16o 12E0-4- f -_- 28.20! I: h_ _ 35.25+ - - + i , 42.50- . _- - 4955_ - ,_ :zk_ -._ _ .-_L_. _ _._ =-_/ ,J_./jk,. ;-0 I0 20 50 40 50.a,deg()60 70 8
34、0 90Figure 4.- Variation of longitudinal force, normal force, and pitchingmoment with angle of attack. Propeller speed, 6,000 revolutions perminute) inlet-lip diameter, 0.50 inch; pitching moment referred toquarter chord.Provided by IHSNot for ResaleNo reproduction or networking permitted without li
35、cense from IHS-,-,-i0 NACA TN 3547A,rspeed, ft/secFigure 5.- Variation of lift, dra_, and pitchLng moment with airspeed.Propeller speed, _,000 revolutions per minute; inlet-lip diameter,0.50 inch; pitching moment referred to quarter chord.Provided by IHSNot for ResaleNo reproduction or networking pe
36、rmitted without license from IHS-,-,-NACA TN 3547 ii_Q+_,-I-C-G)EoE(:Dc-On-_QJo_-t=.840-.4-.840-4-8-122O - _,degCl . 0o-I0-20“(2-,_, “14_y_ - v_-t_ 43b, _L - _ c N-0 -, _ A16n6 12OOZ40-4 0 I0,_ U_ _:2!.0“1 _:I/jl“,1“3J.I )/o20 30 40 50 60Airspeed, fl/secFigure 6.- Variation of longitudinal force, no
37、rmal force, and pitchingmoment with airspeed. Propeller speed, 6,000 revolutions per minutelinlet-lip diameter_ 0.50 inch; pitching moment referred to quarterchord.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-12 NACATN 3547ID.8/o /r/,i.6.4.20 L l0 .8 1.6 2.4 3.2Lip dlarneter, _n.Figure 7.- Variation of“ static-thrust efficic:ncy with lip diameter.NACA - Langley Field, Va.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
