COMPUTER PROGRAM USER'S MANUAL FOR ... - CAFE Foundation

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&AF - activity factor adjustment factor to torque (ref. 2, fig. 11) AC - integrated design lift coefficient adjustment factor to torque for Q:E2 J s 1.0 (ref. 2, fig. 12) PCR - percentage of integrated design lift coefficient adjustment factor to be used (ref. 2, fig. 13) QC *QC cT T~~ TC ATC - torque coefficient for J r 1.0 - integrated design lift coefficient adjustment factor to torque E2 for J 2 1.0 (ref. 2, fig. 15) - thrust coefficient for J s 1.0 - activity factor adjustment factor to thrust (ref. 2 , fig. 17) - integrated design lift coefficient adjustment factor to thrust E2 for J s 1.0 (ref. 2, fig. 18) - thrust coefficient for J 5 1.0 - integrated design lift coefficient adjustment factor to thrust ~2 for J > 1.0 (ref. 2, fig. 18) This performance generalization format is shown for 3-bladed propellers referenced to 100 activity factor and 0.4 integrated design lift coefficient on figures 3 and 4 for the effective torque coefficients and effective thrust coefficients, respectively. The complete generalization together with detailed instructions for computing the reverse angle for a given throttle setting and the reverse thrust over the landing distance run with the propeller fixed at the reverse angle are presented in reference 2. Propeller Noise Generalization For assessing propeller noise, the far field perceived noise level (PNL) was selected as the noise rating scale because: 1) It is a good measurement of the relative annoyance of the various aircraft designs considered in general aviation aircraft, 2) It can be estimated by use of a relatively simple calculation procedure, and 3) It is a reasonable indication of the subjective reaction to aircraft noise. An empirical method €or predicting far-field perceived noise levels, PNdB de- veloped at Hamilton Standard has been included in the computer program. It presents a means of calculating noise for a broad range of propeller design and operating para- meter s. 11
The required inputs to the propeller noise estimating method are: 1. Propeller diameter 2. Number of blades per propeller 3. Propeller RPM or tipspeed 4. Shaft horsepower per propeller 5 Ambient temperature 6. Aircraft forward speed 7. Number of propellers installed 8. Distance from the propeller center of the desired field point at which the noise is to be measured. The computational procedure consists of a basic noise level (dB) curve (fig. 5) for a 4-bladed, 10.5 foot diameter propeller defined at 500 feet from the propeller center. The base curve is a function of shaft horsepower and rotational tipspeed. There are adjustments for variations in diameter, number of blades, and distance from the propeller center. Then, there is an adjustment to obtain the corresponding perceived noise level. The directivity pattern of the noise emanating from the propeller is ignored, and the perceived noise level is computed for the azimuth angle for which the noise is a maximum. Recent test data on highly loaded low tipspeed propellers have indicated that the reduction in noise with tipspeed is a function of propeller stall characteristics. It appears that noise reductions can be achieved with decreasing tip speed at a given power only to the point where the propeller stall is limited to approximately the inner 50% of the blades. The 50% stall region is defined on the base Cp and CT curves (fig. 1 and 2). It is recommended that propellers be selected to operate to the left of the indicated 50% stall line. The detailed procedure is explained in APPENDIX B of reference 1. Since this generalization is for propellers only, it is emphasized that the low noise levels which may be achieved through selected design and operating conditions will not be representative of those from the complete aircraft unless a parallel effort is made to reduce the noise from other sources (particularly from the engine) as these will become predominant and set the perceived noise level of the aircraft. 12
Page 1 and 2: k .” c - 1. -a “ ”- NASA *o *
Page 4 and 5: CONTENTS SUMMARY 1 INTRODUCTION SYM
Page 6: SUMMARY A major outcome of the stud
Page 10 and 11: AF b B C LD C Li cP C Q cT D h J M
Page 12 and 13: TECHNOLOGY IDENTIFICATION ' General
Page 14 and 15: cT T~~ - thrust coefficient - activ
Page 18 and 19: Propeller Weight Generalization A w
Page 20 and 21: Propeller 1. Diameter range 2. Numb
Page 22 and 23: PARAMETRIC STUDY OPTIONS Having dev
Page 24 and 25: 1. 2. 3. 4. 5. 6. 7. a. 9. 10. Card
Page 26 and 27: 6. RPM for zero velocity, full thro
Page 28 and 29: For the option where tipspeed for 5
Page 30 and 31: CONCLUDING REMARKS 1. Generalizatio
Page 32 and 33: j Aircraft Class Seats I. Single En
Page 34 and 35: Y (I) 4 w EFFECTIVE POWER COEFFICIE
Page 36 and 37: I 3 BLADES/IOO AF/O.~ cLi BLADE ANG
Page 38 and 39: PROPELLER INPUT HORSEPOWER FIGURE 5
Page 40 and 41: ~ ja, m ~ MINIMUM CRUISE 370# THRUS
Page 42 and 43: I CATEGORY V I LANDING SPEEDS, KNOT
Page 44 and 45: w W JOB NO.: ACCT. NO: W.O. NO.: !
Page 46 and 47: HAMILTON STANQARD CflMPUTER DECK Nf
Page 48: 2FClPR7CATIVG F'IGI'JF 650. 547. 21
Page 51 and 52: DETERMINE TIPSPEED AT WHICH BLADE W
Page 53 and 54: . FORTRAN .CY G LEVEL 2011 HA1 N DA
Page 55 and 56: FORTRAN .I.V G LEVEL 2011 . . MA I
Page 57 and 58: FORTRAN I V G LEVEL 20.1 MA IN OATE
Page 59 and 60: FClQTR41 IV G LEVEL 70.1 INPUT DATE
Page 61 and 62: 0017 00 19 00 19 0020 0021 0022 56
Page 63 and 64: FORTRAN I V G LEVEL 20.1 PERFM DATE
Page 65 and 66: FORTRAN IV G LEVEL 20.1 PERFM DATE
Page 67 and 68:
. " . -. . . . IDRTRAN .IV..G LEVEL
Page 69 and 70:
FOPTRAU 1V C, LFVFL 23.1 ZNO I SF D
Page 71 and 72:
FORTRAN I V G LEVEL.. 20.1 . . " .
Page 73 and 74:
0035 0006 0007 001 0 FIGURE 3A. FOR
Page 75 and 76:
. .. F3RTpAN 1V.G LFVEL 20,l 0063 0
Page 77 and 78:
FI?RTP.AY IV G LEVEL 20.1 R IOUAD D
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