1、RESEARCH MEMORANDUM INVESTIGATION OF THE NORMAL FORCE ACCOMPANYING THRUST- AXIS INCLINATION OF THE NACA 1.167(0)(03)-058 AND THE NACA 1.167.(0)(05)-058 THREE-BIXDE PROPELLERS AT FORWARD MACH NUMBERS TO 0.90 By Fred A. Demele and William R. Otey Ames Aeronautical Laboratory Moffett Field, Calif. NATI
2、ONAL ADVISORY COMMITTEE FOR AERONAUTICS f I 3 WASHINGTON June 23,1954 I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-u NACA RM A54D2!2 * NATIONAL ADVISORY COMMITTEE FOR RESEARCHMEZ4ORARDUM AERONAUTICS INVESTIGATION OF TRE NORMAL FORCE ACCOMPANYING
3、 THRUST- AXIS INCLINATION OF TEZE NACA 1.167-(0)(03)-058 AND THE NACA 1.167-(0)(05)-058 TECEUZE-BLADE PROPELLERS AT FORWARD MACH NME3ERS To 0.90 By Fred A. Demeleand William R. Otey SUMMARY An investigation has been conducted to determine experimentally the normal force of the NACA S.l67-(0)(03)-058
4、 and the RACA 1.167-(o)(o)-058 three-blade propellers and to ascertain the agreement of the measured normal force with a theoreticsl method developed herein. The propeller thrust and normal force were measured with the thinner propeller for a range of blade angles and angles of attack at forward Mac
5、h numbers from 0.60 to 0.90. For the thicker propeller, similar measurements were made at forward Mach numbers of 0.0 pWsb Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA RM A.54E22 3 CfQ % D b 6 fn fQ h h 6 J r r PO II free-stream velocity loca
6、l forward veloc-fty axial interference velocity resultant interference velocity rotational interference velocity rearward displacement velocity of helical vortex surface at infinity ratio of displacement velocity to component of local forward velocity parallel to thrust axis blade-section helical ve
7、locity considering induced effects blade-section helical velocity neglecting induced effects fraction of tip radius, G ratio of spinner radius to tip radius, 2 angle- of attack of the thrust axis tith respect to the free-atream direction blade-section angle of attack propeller induced angle of inflo
8、w blade angle at 0.7 radius blade angle tan-= Cd 0 cz absolute viscosity free-stream density propeller solidity, whereas normal force is resolved from the measured lift and longitudinal force in a direction normalto the thrust axis. The forces were measured by the six-camponent balance system. Seal-
9、Pressure Correction The pressures acting on either side of the concentric seal were measured, and the forces resulting from the measured pressures were adjusted for computational purposes to correspond to a reference pres- sure equal to the free-stream static pressure. The appropriate component of t
10、his pressure force was applied to the measured thrust for tests with the propeller operating and also with the propeller removed. Choice of free-stream static pressure for a reference pressure deterrntned the net tare force but had no effect on either the propeller thrust or normal force as deftied
11、herein. Tunnel-Wall Correction The data have been corrected for the effect of tunnel-wall constraint on the velocity in the region of the propeller plane by the method of reference 3. The magnitude of the maximum correction applied to the data was 0.7 percent. The constriction effects, due to operat
12、ing the propeller, were evaluated by the method of references 4 and 5 and were found to be negligible. Accuracy of Results Analysis of the sources of error and correlation of test data for duplicate conditFons indicated the maximum probable errors in the data were as follows: Provided by IHSNot for
13、ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA FMA54D22 THEORETICAL CONSIDF pbcz (Vt COB A + Vi cos (P) Ial cp (1 + tan y cot cp) (6) which may be written in coefficient form as CfQ = 2 cos2 At sin cp + Vi COB cp 2 (I+ tan y cot q (7) V COB A The aerodynamic excitati
14、on of the propeller blades, due to the angle of upflow At, is essentially sinusoidal in character and peaks at Sr = go0 and n = 270. If it is assumed that the propeller blade is operating far below resonance in first-mode bending, the oscillating thrust and torque force due to At are also sinusoidal
15、 and in phase with the aerodynamic disturbance. It then follows that the amplitude of the once-per-revolution torque-producing force is given by 1 fQ1Xp =z ( fQa=so - %62=270 The relationship between the normal force and the torque-producing force is fn = fQ sti n from which the average section norm
16、al force per blade per revolution can be expressed as fn If = E = f Qw= the second method relies on an application of Theodorsents circulation function and fs more general in that an arbi- trary blade loading can be considered. In the application of Goldsteins theory, equation (7) is modified by the
17、 basic assumption (ref. 6) that tan ay = *=it vi =- 4K sfn q3 W From the geometry of the velocity diagram, the following expression may be stated: (cot Since, by definition u cp + tan c co2 q (l + tan 7 cot q) (13) wherein the dimensionless parameter F is related to Theodorsents circulation function
18、 (ref. 9). For the present calculations 7 was evaluated with the use of reference 10, wherein this parameter is PreBented as a function of blade loading and advance ratio. In determining 7, values of advance ratio for the propeller uninclined were used. This assumption implies that the Interference
19、velocity is dependent on the element blade loading for the condition of propeller unfnclined, but does not preclude use of instantaneous blade position for the determination of blade-section angle of attack. In determination of the blade-section angles of attack, the blade twist due to the combined
20、effects of centrifugal force and steady loading was accounted for. A more rigorous solution should include the blade twist due to the oscillating afr loads, and also any effect of blade vibration on either the instantaneous blade angle or on the phase lag between the Ixp excitation and the resulting
21、 blade forces for conditions in which WF resonance is approached. Reference ll was the source of the two-dImensional data for NACA 16-series airfoils used in performing the calculations. Reference 12 was used for obtaining the radial distribution of upflow angle, and the radial distribution of veloc
22、ity was calculated by the following cubic equation: F = 1.0 + 0.08 $ S (-El RESULTS The results of this investigation are presented in figures 4 through 10. In figures 4 and 5 the thrust character.istics of the propellers are shown. The normal-force characteristics are presented in ffgures 6 and 7 a
23、s a function of thrust coefficient and in figures 8 and 9 as a function of upflow angle at the 0.7 propeller radius. A comparison of the normal-force coefficient as determined from theory and experiment is shown in figures 8(b), 9 and 10. wy1) Provided by IHSNot for ResaleNo reproduction or networki
24、ng permitted without license from IHS-,-,-I2 DISCUSSION Variation with Thrust NACA RM A54D2!2 The basic normal-force data as presented in figure 6 indicate that for the thin propeller, the normal-force coefficient generally increased slightly with fncreasing thrust coefficient at Mach numbers below
25、0.70 and remained essentially constant at higher Mach numbers. The low-speed data for the thicker propeller (fig. 7) indicate that the normal-force coefficient generally increased with increasing thrust coefficient, the effect becoming more pronounced with increasing angle of attack. Effect of Incli
26、nation Propeller normal-force coefficient is shown as a function of upflow angle at the 0.7 propeller radius in figure 8 for the thin pro- peller, and in figure 9 for the tucker propeller. The angle of upflow at the propeller disk differs from the angle of attack of the thrust axis by the upwash ind
27、uced by the spinner and nacelle. The relationship between the measured upflow angle and the angle of attack of the thrust axis has been determined from the data of reference 12 and is as follows: M it I “:% to 1.185 -70 1.174 .80 1.144 083 1.130 .86 1.120 090 1.100 For the thin propeller, the increa
28、se in normal-force coefficient with upflow angle was essentially linear (fig. 8). It is also seen from this figure that the slope of the normal-force curves is slightly reduced with increasing Mach number and slightly increased with increasing blade angle. The trend of normal-force coefficient tith
29、upflow angle for the thicker propeller was essentially linear, the greatest deviation from linearity occurring at a thrust coefficient of 0.6 for a blade angle of 210 (fig. 9). In addition, as previously noted for the thin propeller, the effect of increasing blade angle was an increase in the normal
30、- force coefficient. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA FM A54D22 13 Comparison with Theory It has been stated earlier in the report that the calculation of normal force for a high-speed condition (thin propeller) was performed by t
31、he method in which the induction effects are accounted for by Goldstein theory. The excellent aseement afforded by this method is shown in figure 8(b) for a blade angle of 51 and a Mach number of 0.70. This agreement might have been anticipated because the condition is one for which the loading was
32、light and the lift distribution nearly optimum and, therefore, the loading did not violate the restriction of the Goldstein theory. For conditiaos of low blade angle and low forward speed (thick pweeed, the normal force was calculated by use of the method which accounts for induction effects by Theo
33、dorsens circulation functions. In figure 9 the calculated values have been plotted at the values of upflow angle for which the calculations were made, and to the first order may be linearly extrapolated to zero upflow angle. It is apparent that the effect of thrust-axis inclination on normal-force c
34、oefficient was consistently underestimated by the theoretical method. A more comprehensive comparison 1s made in figure 10, wherein normal-force coefficient is given as a function of blade angle and also as a function of thrust coefficient. It is evident that the vsrfation of normal-force coefficien
35、t with blade angle and thrust coefficfent was predicted with fair accuracy, but that the absolute magnitude of the normal force was underestimated. The discrepancy between the magnitudes of the calculated and experimental values may be due to several possfble sources of error. The first is the uncer
36、tainty of the two-dimensional airfoil data used in calculating the magnitude of the torque-producing force. The second is the assumed radial velocity gradient used in the absence of experimental data. Finally, the upflow angles, which were measured in the absence of the propeller, could conceivably
37、have been larger with the propeller operating. CONCLTJDING REMARKS Results of an investigation of the normal-force characteristics of the NACA 1.167-(0)(03)-058 and the NACA 1.167-(0)(05)-058 three-blade propellers showed that: 1. In general, the normal-force coefficient increased with increasing th
38、rust coefficient at Mach numbers below 0.70 and remafned essentially constant at the higher Mach numbers. 2. The increase in normal-force coefficient with upflow angle was essentially linear. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-14 NACA RM
39、 A522 3. Increasing propeller blade angle increased the normal-force coefficient for a given value of thrust coefficient and angle of attack. 4. Comparison between the calculated normal force and that measured experimentally at a forward Mach nmber of 0.7 indicated excel- lent agreement. 5. At-low f
40、orwardspeeds the theoretical method predicted the variation with thrust coefficient and blade angle of propeller normal force with fair accuracy, but consietently underestimated the effect of thrust-axis inclination. - Ames Aeronautical Laboratory National Advisory Committee for Aeronautic8 Moffett
41、Field, Calif., Apr. 22, 1954 REFERENCES 1. Ribner, Herbert S.: Propellers in Yaw. NACA Rep. 820, 1945. 2. Demele, Fred A., and Otey, William R.: Investigation of the NACA 1.167-(0)(03)-058 and NACA 1.167-(0)(05)-058 Three-Blade Propellers at Forward Mach Numbers to 0.92 Including Effects of Thrust-A
42、xis Inclination. NACA RM A53F16, 1953. 3. Herr-rot, John G.: Blockage Corrections for Three-Dimensional-Flow Closed-Throat Wind Tunnels, With Consideration of the Effect of Compressibility. NACA Rep. 995, 1950. (Formerly NACA RM A7Et28) 4. Glauert, H.: The Elements of Aerofoil and Airscrew Theory. C
43、ambridge, Eng. The Univ. Press3 New York, Macmillan, 1943, pp. 222-226. 5. Young, A. D.: Note on the Application of the Linear Perturbation Theory to Determine the Effect of Compressibility on the Wind Tunnel Constraint on a Propeller. R.67 Provided by IHSNot for ResaleNo reproduction or networking
44、permitted without license from IHS-,-,-,- Seal detail c Motor-support faking Motor support Figure 2.- Nacelle assembly. Oil and water lines, electrical leads h?- Support-strut fairing - Tunnel floor , r OJ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-
45、,-,-NACA RM A54D22 Developed plan form Leading edge 20- . I I I I I I I t I I I I1 1 .I8 - 1 I I t. I .- I Ii h/b. IO and b,D .08 t I I III I.1 I I I I i 1.167-(0X0 02 0 76 72 68 64 56 B 52 36 0 .I .2 .3 .4 .5 .6 .7 -8 .9 1.0 , % t -is7 Figure 3.- Blade-form curves for the NACA Ll67-(0)(03)-058 and
46、the NACA 1.167(0)(05)-058 three-blade propellers, Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Tc .OZ .o I 0 -.Ol 22 2.4 26 28 30 3.2 3.4 IS 2.0 2.2 2.4 2.6 2.8 J 26 28 3D 3.2 34 .03 I .02 Tc .Ol 0 F -.o I $ 26 28 30 3.2 3.4 28 28 30 32 34 2.8 30
47、32 3.4 -!z J Figure 4.- !Chrmt characteristice of the NACA 1.167-(O)(Oj)-0% propeller; R = 1,600,ooO. 8 . . . , I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.6 3 .2 .I 0 I I I I IT t-1 1-t I-4 I T I r I -.I I I I I I I I I I I I .4 .6 .8 ID ID I
48、D ID ID II) _ 8.26 R = 1,600,000. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-08 I 1 .04 CM 0 -04 l- I I I I I I I I I -.Ol 0 .Ol .02 .03 .04 Tc Q. W A 588 0 392 0 0 -3L /bSS” I MlO.83 L- . . . . . . . . . . . . . . - - I I I I 1 I I I M = 0.90 nl c I I -XII 0 .Ol .02 .03 Tc E (c) M = 0.80, 0.83, 0.86, 0.90 Figure 6.- Concluded. . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, , S e b “T A 7.04
