NASA Contractor Report 178004

NASA-CR-178004

19860010618

•

Acoustic Measurements

Twin-Engined

Airplane

In - Flight

on a Light

Turboprop

J.F.Wilby, C.D.McDaniel and E.G.Wilby

BBN Laboratories Inc.

Canoga Park, CA 91303

Contract NAS1-16521

November 1985

....

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National Aeronautics and

Space Administration

Langley Research Center

Hampton Virqinia 23665

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NASA Contractor Report 178004

%

IN-FLIGHT ACOUSTIC MEASUREMENTS ON A LIGHT TWIN-ENGINED

TURBOPROP AIRPLANE

J. F. Wilby

C. D. Mc Daniel

E. G. Wilby

BBN Laboratories Incorporated

A Subsidiary of

Bolt Beranek and Newman Inc.

Canoga Park, California 91303

Contract NASI-16521

• November 1985
d
TABLE OF CONTENTS

• Section Page

1.0 INTRODUCTION .................... i

2.0 TEST DESCRIPTION .................. 3

2.1 Test Airplane ................. 3

2.2 Test Condition ................. 7

2.3 Instrumentation ................ 14

2.4 Interior Configuration ............. 21

3.0 EXTERIOR FLUCTUATING PRESSURE FIELD ......... 26

3.1 Narrowband Spectra ............... 26

3.2 Harmonic Data Variability ........... 33

3.3 Comparison of Port and Starboard Levels .... 43

3.4 Comparison with Simplified Predictions ..... 46

3.5 Relative Phase ................. 52

3.6 Turbulent Boundary Layer ............ 56

3.7 One-Third Octave Band Spectra ......... 57

4.0 SOUND LEVELS IN UNTREATED CABIN ........... 60

4.1 Narrowband Spectra ............... 60

4.2 Harmonic Data Variability ........... 62

4.3 One-Third Octave Band Spectra ......... 75

5.0 SOUND LEVELS IN TREATED CABIN ............ 77

6.0 DISCUSSION ..................... 82

6.1 Cabin Presurization............... 82

6.2 Sidewall Noise Reduction ............ 92

6.3 Insertion Loss ................. 102

7.0 CONCLUSIONS ..................... i14

7.1 Data Variability ................ 114

7.2 Exterior Sound Pressure Levels .......... 115

7.3 Interior Sound Pressure Levels ......... 116

7.4 General Comments ................ 117

REFERENCES ........................ 118

i
TABLE OF CONTENTS

Continued

Section Page

APPENDIX:

A. EXTERIOR FLUCTUATING PRESSURE LEVELS AT HARMONICS OF

PROPELLER BLADE PASSAGE FREQUENCY ........... 121

B. INTERIOR SOUND PRESSURE LEVELS AT HARMONICS OF PROPELLER

BLADE PASSAGE FREQUENCY: BARE INTERIOR ........ 129

C. INTERIOR SOUND PRESSURE LEVELS AT HARMONICS OF PROPELLER

BLADE PASSAGE FREQUENCY: TREATED INTERIOR ...... 149

D. ONE-THIRD OCTAVE BAND SPECTRA FOR EXTERIOR FLUCTUATING

PRESSURES ....................... 157

E. ONE-THIRD OCTAVE BAND SPECTRA FOR INTERIOR SOUND

PRESSURES: BARE INTERIOR .............. 167

F. ONE-THIRD OCTAVE BAND SPECTRA FOR INTERIOR SOUND

PRESSURES: TREATED INTERIOR ............. 181

G. EFFECTS OF CABIN PRESSURIZATION ON CABIN SOUND

PRESSURE LEVELS .................... 195

H. NOISE REDUCTION FOR UNTREATED CABIN .......... 199

I. NOISE REDUCTION FOR TREATED CABIN ........ 205

J. INSERTION LOSS PROVIDED BY TREATMENT: NO ADJUSTMENTS

FOR CHANGES IN EXTERIOR SOUND PRESSURE LEVELS ..... 211

K. INSERTION LOSS PROVIDED BY TREATMENT: ADJUSTED FOR

CHANGES IN EXTERIOR SOUND PRESSURE LEVEL ....... 219 m

ii
LIST OF FIGURES

Figure Page

i. Test Airplane ..................... 4

2. Three-View Diagram of Test Airplane .......... 5

3. Aircraft Station, Water Line, and Body Line Locations 6

4. Locations of Microphones Inside Cabin and On Exterior

of Fuselage ...................... 17

5. Interior of Bare Cabin Showing Installed

Instrumentation .................... 19

6. External Microphone and Pressure Sensors ....... 20

7. Samples of Sound-Absorbing Treatments ......... 23

8. Sound-Absorbing Material Installed in Cabin ...... 24

9. Narrowband Spectra of External Fluctuating Pressure

Field Measured on Port Side of Fuselage. (Propellers

Operating at Different RPM) .............. 27

i0. Narrowband Spectra of External Fluctuating Pressure

Field Measured on Starboard Side of Fuselage.

(Propellers Operating at Different RPM) ........ 29

ii. Narrowband Spectra of External Fluctuating Pressure

Field Measured on Port Side of Fuselage During

Single-Engine Operation ................ 31

12. Narrowband Spectra of External Fluctuating Pressure

Field Measured on Starboard Side of Fuselage During

Single-Engine Operation ................ 32

13. Variability of Harmonic Sound Levels on Exterior of

Fuselage. (Component From Nearest Propeller, Port

Side, Low RPM) .................... 35

14. Variability of Harmonic Sound Levels on Exterior of

Fuselage. (Component from Nearest Propeller, Port

Side, High RPM) .................... 37

15. Variability of Harmonic Sound Levels on Exterior of

Fuselage. (Component from Nearest Propeller,

Starboard Side, Low RPM) ............... 39

16. Variability of Harmonic Sound Levels on Exterior of

• Fuselage. (Component from Nearest Propeller,

Starboard Side, High RPM) ............... 41

17. Comparison of Range of Harmonic Sound Pressure

Levels Generated by Port and Starboard Propellers

(Flights 1-4) ..................... 44

18. Comparison of Measured and Predicted Propeller

Harmonic Sound Pressure Levels: 3,000 m Altitude . 48

iii
LIST OF FIGURES

Continued

Figure Page

19. Comparison of Measured and Predicted Propeller

Harmonic Sound Pressure Levels: 4,600 m Altitude,

Two-Engine Operation ................. 49

20. Comparison of Measured and Predicted Propeller

Harmonic Sound Pressure Levels: 4,600 m Altitude,

Single-Engine Operation ............... 50

21. Comparison of Measured and Predicted Propeller

Harmonic Sound Pressure Levels: 9,100 m Altitude . . . 51

22. Typical Propeller Pressure Time Histories Measured

on Exterior of Fuselage ............... 53

23. Coi_arison of Propeller Pressure Time Histories and

Cross Correlation Function for the Two Signals .... 54

24. Comparison of Measured Exterior One-Third Octave

Band Pressure Spectra and Predicted Turbulent

Boundary Layer Pressure Levels ............ 58

25. Typical Narrowband Sound Pressure Spectrum Measured

in Untreated Cabin ................ 61

26. Narrowband Spectra of Cabin Sound Pressure Levels at

Location 3; Port Propeller, Low RPM; Starboard

Propeller, High RPM ................. 63

27. Narrowband Spectra of Cabin Sound Pressure Levels at

Location 3; Port Propeller, High RPM; Starboard

Propeller, Low RPM .................. 64

28. Narrowband Spectra of Cabin Sound Pressure Levels at

Location 3; Single-Engine Operation ......... 65

29. Comparlson of Harmonic Sound Pressure Levels

Measured in Untreated Cabin Under Repeated Flight

Conditions; Propellers at Different RPM: Microphone

Location 3 ...................... 66

m

30. Comparlson of Harmonic Sound Pressure Levels

Measured in Untreated Cabin Under Repeated Flight

Conditions; Propellers at Different RPM; Microphone Location 6 ................... 67

31. Comparlson of Harmonic Sound Pressure Levels

Measured in Untreated Cabin Under Repeated Flight

Conditions; Propellers at Same RPM; Microphone

Location 3 ...................... 69

iv
LIST OF FIGURES

Continued

Figure Page

32. Comparison of Harmonic Sound Pressure Levels

Measured in Untreated Cabin Under Repeated Flight

Conditions; Propellers at Same RPM; Microphone

Location 6 ..................... 70

33. Range of Harmonic Sound Pressure Levels Measured

in Untreated Cabin for Flights 1 through 3.

Propellers at Same RPM; Data Averaged Over Four

Nominal Synchrophase Settings ............ 72

34. Time Histories of Harmonic Sound Pressure Levels in

Cabin; Two Engines Operating at Different RPM

(Condition 9) .................... 74

35. Time Histories of Harmonic Sound Pressure Levels in

Cabin; Two Engines Operating at Same RPM

(Condition 8) .................... 76

36. Effect of Fiberglass Treatment on Cabin Narrowband

Sound Pressure Level Spectra: Altitude 9,100 m .... 78

37. Effect of Fiberglass Treatment on Cabin Narrowband

Sound Pressure Level Spectra: Altitude 4,600 m .... 80

38. Narrowband Spectra of Cabin Sound Pressure Levels at

Location 3; Effect of Cabin Pressure Differential.

(Airplane Altitude 3,000 m) ............. 83

39. Change in Harmonic Sound Pressure Level in Cabin Due to

Cabin Pressure Differential. Microphone Location 3;

Port Propeller Component, High and Low RPM ...... 85

40. _%ange in Harmonic Sound Pressure Level in Cabin Due to

Cabin Pressure Differential. Microphone Location 3;

Starboard Propeller Component, High and Low RPM . . . 86

41. Change in Harmonic Sound Pressure Level in Cabin Due to

Cabin Pressure Differential. Microphone Location 6;

Port Propeller Component, High and Low RPM ...... 87

42. Change in Harmonic Sound Pressure Level in Cabin Due to

" Cabin Pressure Differential. Microphone Location 6;

Starboard Propeller Component, High and Low RPM . 88

43. Change in One-Third Octave Band Sound Pressure Level in

Cabin Due to Change in Cabin Pressure Differential;

Microphone Location 3 ................ 89

44. Change in One-Third Octave Band Sound Pressure Level in

Cabin Due to Change in Cabin Pressure Differential;

Microphone Location 6 ................ 90

v
LIST OF FIGURES

Continued

Figure Page

45. Harmonic Noise Reduction for Untreated Cabin:

Flight 3, Exterior Port Microphone, Interior

Microphone Location 6 ................ 93

46. Harmonic Noise Reduction for Untreated Cabin:

Flight 3, Exterior Starboard Microphone, Interior

Microphone Location 3 ................ 94

47. Harmonic Noise Reduction for Treated Cabin:

Flight 4, Exterior Port Microphone, Interior

Microphone Location 6 ................ 95

48. Harmonic Noise Reduction for Treated Cabin: Flight

4, Exterior Starboard Microphone, Interior

Microphone Location 3 ................ 96

49. One-Third Octave Band Noise Reduction for Untreated

Cabin: Flight 3, Exterior Port Microphone, Interior

Microphone Location 6 ................ 98

50. One-Third Octave Band Noise Reduction for Untreated

Cabin: Flight 3, Exterior Starboard Microphone,

Interior MicroPHone Location 3 ........... 99

51. One-Third Octave Band Noise Reduction for Treated

Cabin: Flight 4, Exterior Port Microphone, Interior

Microphone Location 6 ................ i00

52. One-Third Octave Band Noise Reduction for Treated

Cabin: Flight 4, Exterior Starboard Microphone,

Interior Microphone Location 3 ........... i01

53. Harmonic Insertion Loss Provided by Fiberglass

Treatment: Port Propeller Component, Interior

Microphone 3. (No Adjustment for Change in Exterior

Sound Pressure Level) ................ 104

54. Harmonic Insertion Loss Provided by Fiberglass

Treatment: Starboard Propeller Component, Interior

Microphone 3. (No Adjustment for Change in Exterior

Sound Pressure Level) ................ 105

55. Harmonic Insertion Loss Provided by Fiberglass

Treatment: Port Propeller Component, Interior

Microphone 6. (No Adjustment for Change in Exterior

Sound Pressure Level) ................ 106

56. Harmonic Insertion Loss Provided by Fiberglass

Treatment: Starboard Propeller Component, Interior

Microphone 6. (No Adjustment for Change in Exterior

Sound Pressure Level) ................ 107

vi
LIST OF FIGURES

Continued

. Figure

57. Harmonic Insertion Loss Provided by Fiberglass

Treatment: Starboard Propeller Component, Interior

Microphone 3. (Adjusted for Change In Exterior

Sound Pressure Level) ................ 108

58. Harmonic Insertion Loss Provided by Fiberglass

Treatment: Port Propeller Component, Interior

Microphone 6. (Adjusted for Change in Exterior

Sound Pressure Level) ................ 109

59. One-Third Octave Band Insertion Loss Provided by

Fiberglass Treatment: Interior Microphone Location

3. (No Adjustment for Change in Exterior Sound

Pressure Level) ................... iii

60. One-Third Octave Band Insertion Loss Provided by

Fiberglass Treatment: Interior Microphone Location 6.

(No Adjustment for Change in Exterior Sound Pressure

Level)

....................... 112

vii
LIST OF TABLES

Table Page

i. Nominal Flight Test Conditions ............ 8

2. Flight Test Conditions: Flight #i .......... 9

3. Flight Test Conditions: Flight #2 .......... i0

4. Flight Test Conditions: Flight #3 .......... ii

5. Flight Test Conditions: Flight #4 .......... 12

6. Fuselage Skin Temperature Measured During Flight #4. 15

7. Locations of Cabin Microphones ............ 18

8. Locations of Transducers on Fuselage Exterior .... 18

9. Measured and Predicted Exterior Overall Sound

Pressure Levels Associated with Propeller Discrete

Frequency Sound ................... 45

i0. Relative Phase Between Port and Starboard Propellers 56

ii. Assumed Acoustic Absorption Properties ........ 113

viii
ACKNOWLEDGMENT

The experimental investigation described in this report was

performed by BBN Laboratories Incorporated under Task 15 of NASA

Contract NASI-16521, with Dr. John S. Mixson as Technical Monitor.

However, the program received considerable support from the

Gulfstream Aerospace Company, who provided the test airplane and

flight crew free of charge. The authors wish to acknowledge this

contribution. In addition, the authors would like to thank

Gulfstream Aerospace staff members Mr. R. O'Neal, Manager of

Environmental Engineering, Mr. J. Morehead, Manager of Test

Engineering, and Mr. A. Hernandez, Test Pilot, for their significant contributions to the test program.

ix

1.0 INTRODUCTION

As part of a comprehensive NASA program to reduce sound levels in

general aviation aircraft, several analytical, laboratory, ground

run-up, and flight studies have been performed on light, twinengined, propeller-driven airplanes [i-19]. All the aircraft investigated were of the same basic configuration, but in the earlier studies an unpressurized, piston-engined airplane was used

while, later, a pressurized, turboprop model was considered.

Flight measurements were performed on the turboprop airplane in

1981 to evaluate an experimental sidewall treatment. The results

of these measurements [9, 19] showed a large variability in the

data so that it was difficult to evaluate the acoustic performance

of the treatment. In addition, the treatment did not provide the

desired noise reductions. Consequently, a second series of flight

tests was planned with the two main objectives of, first, establishing a test procedure to minimize the variability of the data

and, secondly, evaluating the noise reduction characteristics of a

sidewall treatment designed to provide high transmission loss.

The first phase of the flight test series was conducted in May

1984. Four flights were performed, three with an untreated cabin

and one with the cabin lined with 5-cm (2-inch) thick fiberglass

batts. Unfortunately, the test airplane was not available for the

second phase of the flight test series. Consequently, it was not

possible to evaluate the new sidewall treatment. This report presents data for the first phase only.

Data from the four flights are presented in a series of appendices

I included in this report. The main text of the report provides

descriptions of the test airplane, test procedures and instrumentations of the test airplane (Section 2) followed by discussion

-i-
of the results. Section 3 discusses the exterior sound field,

Section 4 the interior sound field in the untreated cabin, and

Section 5 the sound field in the cabin lined with fiberglass. A

general discussion of the results is provided in Section 6.

-2-
2.0 TEST DESCRIPTION

. 2.1 Test Airplane

The airplane used for the tests was a Gulfstream Aerospace

Commander 695A (Serial Number 96000, Registration N81502). This

airplane is a high-wing business aircraft with a maximum take-off

weight of 5079kg (11,200 ib). It has a pressurized cabin and

retractable landing gear. The particular aircraft used for the

measurement program was an airplane operated by Gulfstream

Aerospace Corporation in support of certification and engineering

test requirements. Thus, the fuselage interior did not contain

standard sidewall treatment or cabin furnishings.

The Commander 695A is powered by two AiResearch TPE331-10-501K

single-shaft, turboprop engines which have a nominal rating of 610

kW (820 SHP). The engines drive Dowty Rotol three-bladed propellers with super-critical airfoil sections. The propellers have a

diameter of 2.69m (106 inches) and the minimum clearance between

the fuselage and the propeller tip is 0.36m (14 inches) or 0.13D,

where D denotes the propeller diameter. The maximum rotational

speed of the TPE331-10-501K engine is 41,800 rpm. There is a twostage reduction gear box, with an overall gear ratio of 26.3:1

connecting the engine to the propeller. The maximum speed of the

propeller is 1591 rpm and the direction of rotation is counterclockwise when viewed from the rear. Engine exhausts are located

on the outboard side of each nacelle.

Photographs of the test airplane are shown in Figure i, and a

three-view diagram is given in Figure 2. The fuselage structure

of the Commander 695A is of conventional skin-longeron-frame

construction. The thickness of the fuselage sidewall skin panels

is typically 1.6mm (0.063 inch) and the longitudinal stiffeners

consist mainly of longerons at vertical stations (water line)

WL-10.00, WL-28.00 and WL-55.00, as shown in Figure 3. Locations

-3-
\

FIGURE I. TEST AIRPLANE

-4-
15o9 m (52.1 ft)

13.1 m (42.9 ft) _i

FIGURE 2. THREE-VIEW DIAGRAM OF TEST AIRPLANE

-5-
00 0 0 c c c c ccuian

'¥

'\.""l--..;----366.60

l-----\.----346.60

1----.....;.---326.00

1----~.---308.00

000

o Ie

g~

N~:'-'-\----386.B2

172.50- :

I

Prop 91.'6 -~-+-_

69.00 --:::=J:::~t~l=-:=:=,L-.......

253.32 ----I---t--1

272.00 - ---H-=-'1

28B.00 - 1-+--1

304.00 ----I-'---{

313.6B --_."-___

113.00 --::=1==J~-::;;::-r--~

0.00 -Tl.-'-"-T----t

2407 _.L_

::9.00 ----If--+---t---j

160.00 ----t--f----t..,..,.

178.66 ----t--t-.,

197.32 ----

216.00 ----t---j,-;

234.66 ----1--+--1

142.00 ----t--t---I

FIGURE 3. AIRCRAFT STATION, WATER LINE, AND BODY

LINE LOCATIONS

-6-
of the frames and cabin windows are also shown in Figure 3, where

station, body line and water line numbers are given in inches.

2.2 Test Conditions

Four flights were performed with the intention of repeating the

same test conditions on each flight. The nominal test conditions

are given in Table 1 and the actual conditions for each flight

(logged by the flight test engineer in the copilot's seat) are

listed in Tables 2 through 5. Unfortunately, the propeller

synchrophaser* system was not operating during the fourth flight

and several of the test conditions could not be achieved. The

first three flights were performed with the cabin untreated. No

changes were made to the cabin contents between these flights and

the transducers were not moved. Following the third flight, the

acoustic instrumentation was removed so that the fiberglass batts

could be installed. The instrumentation was reinstalled prior to

the fourth flight.

Flight #1 was conducted on the morning of 15 May 1984, originating

and ending at Wiley Post Airport, Bethany, OK; data were recorded

during the period 0935 hours to Ii00 hours, CDT. Flights #2 and

#3 were both conducted during the morning of 16 May 1984. Flight

#2 originated at Wiley Post Airport and terminated at Nashville

Airport, TN, data being recorded from 0725 hours to 0840 hours

CDT. Flight #3 was the return flight to Wiley Post Airport, with

the measurements being made between 1055 hours and 1210 hours.

Flight #4 was a round trip from Wiley Post Airport on the afternoon of 17 May 1984; data were recorded from 1445 hours to 1555

hours.

*The word "synchrophaser" is used by industry to describe equipment which keeps a preset phase relationship between the two propellers while also keeping the propellers at the same rotational

speed. The accuracy with which the relative phase is maintained

can vary considerably between different types of synchrophasers.

-7-
TABI._1

NOMINALFLIGHTTEST _ITI_

CONDT RE_ARKS FLIGHT CABIN CABIN OUTSIDE PROPEI/2_ OPERATING CONDITION RELATIVE

IDh_T, PRESSURE ALTITUDE PRESSURE IAS AIR PORT STARBOARD PHASE

ALTITUDE DIFFER. THMP I SEq_ING

RPM TORQUE POWER RPM TORQUE POWER (2)

m/ft m/ft kNm-2/psi kts °F (I) kW/SHP (I) kW/SHP

1 Zero Pressure Diff. 3.0k/10k 3.0k/10k 0 Not Not 1591 80% Not 1527 80% Not

2 Zero Pressure Diff. 3.0k/lOk 3.0k/10k 0 Speci- Specified 1527 80% Speci- 1591 80% Specifie4

3 Cabin Pressurized 3.0k/10k Normal Normal fled 1527 80% fled 1591 80%

4 Cabin Pressurized 3.Ok/10k Normal NormaI 1591 80% 1527 80%

5 Normal Cruise 4.6k/15k 0.7k/2.3k 36/5.2 1527 80% 1527 80% 9 o'clock

I 6 Normal Cruise 4.6k/15k 0.7k/2,3k 36/5.2 1527 80% 1527 80% II o'clock

OO 7 Normal Cruise 4.6k/15k 0.7k/2.3k 36/5.2 1527 80% 1527 80% I o'clock

I 8 Normal Cruise 4.6k/15k 0.7k/2.3k 36/5.2 1527 80% 1527 80% 3 o'clock

9 Ehgines Diff.RFM 4.6k/15k O.7k/2.3k 36/5.2 1591 80% 1527 80%

I0 Engines Diff.RH_ 4.6k/15k O.7k/2.3k 36/5.2 1527 80% 1591 80%

II Starboard Engine 4.6k/15k 0.7k/2.3k 36/5.2 0 0 1527 80%

12 Port Engine 4.6k/15k 0.7k/2.3k 36/5.2 1527 80% 0 0

13 Normal Cruise 9.1k/30k 2.6k/8.6k 43/6.3 1527 52% 1527 52% 9 o'clock

14 Normal Cruise 9.1k/30k 2.6k/8.6k 43/6.3 1527 52% 1527 52% ii o'clock

15 Normal Cruise 9.1k/30k 2.6k/8.6k 43/6.3 1527 52% 1527 52% 1 o'clock

16 Normal Cruise 9.1k/30k 2.6k/8.6k 43/6.3 1527 52% 1527 52% 3 o'clock

17 Engines Diff.RPM 9.ik/30k 2.6k/8.6k 43/6.3 1591 52% 1527 52%

18 Engines Diff.RI_ 9.Ik/30k 2.6k/8.6k 43/6.3 1527 52% 1591 52%

(I)Torquemeasuredas percentageof nnximum

(2)Relativephasesettingmeasuredarbitrarilyin termsof positionof

coQkpitcontrolknob
TABLE 2

FLIGHT TEST (X]NDITIONS:PLIGHT #I

CCNDT Pd94ARKS FLIGHT CABIN CABIN Otr[_IDE PROPEI/2_ OPERATING CONDITION RELATIVE

IDLE. PRESSURE ALTITUDE PRESSURE IAS AIR PORT STARBOARD PHASE

ALTITUDE DIFFER. Th'4P POWER POWER SETFING

RgM TORQUE kW/S_{P RPM TORQUE kW/S34P (2)

m/ft m/ft kNm-2/psi kts °F (3) (I) (4) (3) (i) (4)

1 Zero Pressure Diff. 3.0k/10k 3.0k/10k 0/0 230 Not 1580 80 484/650 1525 80 468/627

2 Zero Pressure Diff. 3.0k/10k 3.0k/lOk 0/0 230 Recorded 1525 80 468/627 1570 80 481/646

3 Cabin Pressurized 3.Ok/10k 0.6k/2. Ik 24/3.5 230 1528 80 469/628 1573 80 482/647

4 CabinPressurized 3.Ok/lOk O.6k/2.Ik 24/3.5 230 1573 80 482/647 1518 80 465/624

5 NormalCruise 4.6k/15k 0.9k/3.0k 34/4.9 220 1533 80 470/630 1533 80 470/630 9 o'clock

6 NormalCruise 4.6k/15k 0.9k/3.Ok 34/4.9 220 1530 80 469/629 1530 80 469/629 ii o'clock

7 NormalCruise 4.6k/15k O.gk/3.ok 34/4.9 220 1530 80 469/629 1530 80 469/629 1 o'clock

koI 8 NormalCruise 4.6k/15k O.gk/3.0k 34/4.9 220 1530 80 469/629 1530 80 469/629 3 o'clock

I 9 EhginesDiff.RPM 4.6k/15k 0.gk/3.ok 34/4.9 220 1573 80 482/647 1520 80 466/625

i0 EhginesDiff.RPM 4.6k/15k O.gk/3.ok 34/4.9 220 1525 80 468/627 1573 80 482/647

Ii StarboardEngine 4.6k/15k O.9k/3.Ok 34/4.9 Not 0 0 0 1515 72 418/561

12 Port Engine 4.6k/15k O.gk/3.ok 34/4.9 Record- 1520 80 466/625 0 0 0

13 NormalCruise 8.5k/2_ 2.4k/7.gk 43/6.2 ed 1528 Not 1528 Not 9 o'clock

14 NormalCruise 8.5k/2_ 2.4k/7.gk 43/6.2 1528 Recorded 1528 Recorded II o'clock

15 NormalCruise 8.5k/28k 2.4k/7.gk 43/6.2 1528 1528 1 o'clock

16 NormalCruise 8.5k/2_ 2.4k/7.gk 43/6.2 1528 1528 3 o'clock

17 EnginesDiff.RPM 8.5k/28k 2.4k/7.9k 43/6.2 1573 1518

18 EnginesDiff.RPM 8.5k/2_ 2.4k/7.gk 43/6.2 1523 1575

(I)Torquemeasuredas percentageof maximum

(2)Relativephasesettingmeasuredarbitrarilyin termsof positionof

co(_kpitcontrolknob

(3)Basedon frequencyanalysisof acousticdata

(4)Computedfr(]nrpm and torque
TABLE3

FLIGHTTESTODNDITICt_S: FLIGHT#2

C(INDT _ FLIGHT CABIN CABIN OtrI_IDE PROPEl/HER OPERATING OONDITION RFA-ATIVE

IDk_T. PRESSURE ALTITUDE PRESSURE IAS AIR PORT b_ARBGARD _IASE

ALTI'_ODE DIFFER. Th_P POWER POWER SET?ING

RPM TOR(_JE kW/SHP RPM TOR(_UE kW/_m (2)

m/ft m/ft kNm-2/psj kts °F (3) (I) (4) (3) (I) (4)

1 Zero PressureDiff. 3.4k/llk 3.4k/llk 0/0 236 50 1573 82 494/663 1520 81 472/633

2 Zero PressureDiff. 3.4k/llk 3.4k/llk 0/0 235 49 1525 80 468/627 1570 81 487/654

3 CabinPressurized 3.4k/1Ik 0.6k/2.1k 27/3.9 232 49 1525 80 468/627 1570 80 481/646

4 CabinPressurized 3.4k/llk 0.6k/2.1k 27/3.9 234 49 1573 76 458/614 1520 86 501/672

5 NormalCruise 4.6k/15k 0.9k/2.Sk 34/5.0 222 35 1530 80 469/629 1530 80 469/629 9 o'clock

6 NormalCruise 4.6k/15k 0.gk/2.£k 34/5.0 226 35 1533 80 470/630 1533 80 470/630 IIo'clock

I 7 NormalCruise 4.6k/15k 0.9k/2._ 34/5.0 228 35 1530 80 469/629 1530 80 469/629 1 o'clock

8 NormalCruise 4.6k/15k O.gk/2._ 34/5.0 228 35 1530 80 469/629 1530 80 469/629 3 o'clock

o 9 EnginesDiff.R[_4 4.6k/15k 0.9k/2._ 34/5.0 227 34 1575 80 483/648 1520 76 466/625

| 10 EnginesDiff.RPM 4.6k/15k 0.9k/2.Sk 34/5.0 229 34 1525 86 503/674 1570 76 457/613

II StarboardEngine 4.6k/15k O.gk/2._ 34/5.0 170 30 0 0 0 1515 76 441/592

12 Port Engine 4.6k/15k O.gk/2.Sk 34/5.0 170 30 1520 80 466/625 0 0 0

13 NormalCruise 8._/29k 2.4k/7.gk 44/6.4 168 -23 1538 53 312/419 1538 53 312/419 9 o'clock

14 NormalCruise 8._/29k 2.4k/7.gk 44/6.4 168 -23 1538 54 318/427 1538 54 318/427 ii o'clock

15 NormalCruise 8._/29k 2.4k/7.gk 44/6.4 174 -23 1538 54 318/427 1538 54 318/427 1 o'clock

16 NormalCruise 8._/29k 2.4k/7.9k 44/6.4 175 -23 1540 54 318/427 1540 54 318/427 3 o'clock

17 EnginesDiff.P/M 8._/2gk 2.4k/7.gk 44/6.4 173 -23 1570 52 313/420 1518 52 303/406

18 EnginesDiff.RHM 8.Sk/2gk 2.4k/7.gk 44/6.4 174 -23 1523 49 286/384 1573 56 337/452

(I)Torquemeasuredas percentageof maximum

(2)Relativephasesettingmeasuredarbitrarilyin termsof positionof oockpitcontrolknob

(3) Basedon frequencyanalysisof acousticdata

(4)Oomputedfrom _ and torque
TABLE 4

FLIGHT T_ (DO_DITIONS:FLIGHT #3

CONIYP R/_4ARKS FLIGHT CABIN CABIN OUTSIDE PBOPEU2_ OPERATING CONDITION REiATIVE

IDt/_F. PRESSURE ALTITUDE P'RESS_tE IAS AIR PORT SFARBOARD _L%SE

ALTITUDE DI_%'ER. TH_P I_3WER POWER SEITING

RflM TORQUE kW/SHP RI_ TORQUE kW/SHP (2)

m/ft m/ft kNm-2/psJ kts °F (3) (I) (4) (3) (I) (4)

1 Zero PressureDiff. 3.0k/lOk 3.0k/lOk 0/0 233 53 1573 80 482/647 1520 80 466/625 --

2 Zero PressureDiff. 3.0k/lOk 3.0k/lOk 0/0 233 53 1525 80 468/627 1573 81 488/655 --

3 CabinPressurized 3.0k/10k 0.5k/l.7k 26/3.7 230 53 1525 78 456/611 1570 74 445/597 --

4 CabinPressurized 3.0k/lOk 0.Sk/l.7k 26/3.7 230 53 1573 80 482/647 1518 81 471/632 --

5 NormalCruise 4.3k/14k 0.6k/2.1k 34/5.0 220 38 1530 81 475/637 1530 82 481/645 9 o'clock

6 NormalCruise 4.3k/14k 0.6k/2.1k 34/5.0 227 38 1533 82 482/646 1533 83 488/654 IIo'clock

7 NormalCruise 4.3k/14k 0.6k/2.1k 34/5.0 230 38 1530 82 481/645 1530 83 487/653 1 o'clock

8 NormalCruise 4.3k/14k 0.6k/2.1k 34/5.0 230 38 1530 82 481/645 1530 83 487/653 3 o'clock

9 EnginesDiff.RPM 4.3k/14k 0.6k/2.1k 34/5.0 233 39 1573 80 482/647 1520 80 466/625 --

I0 EnginesDiff.Rl_4 4.3k/14k 0.6k/2.1k 34/5.0 230 39 1525 80 468/627 1573 80 482/647 --

II StarboardEngine 4.3k/14k 0.6k/2.1k 34/5.0 183 38 0 0 0 1515 77 447/600 --

12 Port Engine 4.3k/14k 0.6k/2.1k 34/5.0 173 38 1520 79 460/617 0 0 0 --

13 NormalCruise 8.5k/2_ 2.3k/7.4k 44/6.4 170 -19 1525 53 310/415 1525 53 310/415 9 o'clock

14 NormalCruise 8.5k/2_ 2.3k/7.4k 44/6.4 174 -19 1528 53 310/416 1528 53 310/416 II o'clock

15 NormalCruise 8.5k/28k 2.3k/7.4k 44/6.4 173 -19 1528 53 310/416 1528 53 310/416 1 o'clock

16 NormalCruise 8.5k/2_ 2.3k/7.4k 44/6.4 173 -19 1528 53 310/416 1528 53 310/416 3 o'clock

17 EnginesDiff.RFM 8.5k/2_ 2.3k/7.4k 44/6.4 175 -19 1570 53 319/428 1518 53 308/414 --

18 EnginesDiff.RPM 8.5k/2_ 2.3k/7.4k 44/6.4 174 -19 1520 51 297/398 1570 52 313/420 --

(i)Torquemeasuredas percentageof maxinun

(2)Relativephasesettingmeasuredarbitrarilyin termsof positionof oockpitcontrolknob

(3)Basedon frequencyanalysisof acousticdata

(4)Computedfrom rpmand torque
TABLE5

FLIGHT EST(]_NDITI(]NFLIS:(_T#4

CONDT RE_ARKS FLIGHT CABIN CABIN OUTSIDE PROPELLER OPERATING CONDITION RELATIVE

ID_4T. PRESSURE ALTITUDE PRESSURE IAS AIR FORT STARBOARD PHASE

ALTITUDE DIFFER. Th_P POWER POWER SETYING

RPM TORQUE kW/S_{P RPM TOROUE kW/SHP (2)

m/ft m/ft kNm-2/psi kts °F (3) (I) (4) (3) (I) (4)

1 Zero Pressure Diff. 3.4k/llk 3.4k/llk 0/0 228 46 1575 80 483/648 1520 80 466/625 --

2 Zero Pressure Diff. 3.4k/llk 3.4k/llk 0/0 234 46 1525 80 468/627 1570 81 487/654 --

3 Cabin Pressurized 3.4k/llk 0.6k/2. Ik 27/3.9 235 46 1528 80 468/628 1573 82 494/663 --

I 4 Cabin Pressurized 3.4k/llk 0.6k/2. Ik 27/3.9 236 46 1573 80 482/647 1518 81 471/632 --

___ 5 NormalCruise ................

_o 6 NormalCruise ................

I 7 NormalCruise .................

8 NormalCruise ...............

9 EnginesDiff.RPM 4.6k/15k O._/2.6k 35/5.1 221 32 1575 80 483/648 1530 80 469/629 --

i0 _gines Diff.P/M 4.6k/15k 0.8M/2.6k 35/5.1 230 32 1528 80 469/628 1573 82 494/663 --

Ii StarboardEngine 4.6k/15k O._/2.6k 35/5.1 188 32 0 0 0 1515 76 441/592 --

12 PortEngine 4.6k/15k 0._/2.6k 35/5.1 174 32 1520 78 454/609 0 0 0 --

13 NormalCruise 8.5k/2_ 2.3k/7.6k 43/6.3 166 -16 1520 54 315/422 1520 54 315/422 --

14 NormalCruise .............. 15 NormalCruise ----

16 Normal Cruise .............

17 EhginesDiff.RPM 8.5k/2_ 2.3k/7.6k 43/6.3 172 -16 1570 52 313/420 1518 52 303/406 --

18 _gines Diff.RPM 8.5k/2_ 2.3k/7.6k 43/6.3 170 -16 1523 53 309/415 1573 52 314/420 --

(i)Torquemeasuredas percentageof maxim_n

(2)PhasecontrolinoperativeduringFlight#4.

(3}Basedon frequencyanalysisof acousticdata

(4)Co.putedfrom rpm and torque
Three nominal flight altitudes were selected for the test

condition, 3,000 m (i0,000 ft), 4600 m (15,000 ft), and 9100 m

(30,000 ft). The 3,000 m altitude was chosen as a suitable altitude for tests at zero cabin pressure differential; the two higher

" altitudes were chosen to be similar to those of earlier test series [9, 19], with 9200 m being a typical cruise altitude. The

actual values of flight altitude for any given test depended upon

aircraft traffic control constraints at the time of the test.

Propeller torque settings were selected to be typical cruise

conditions--they were also similar to conditions selected in

earlier tests. Propeller rotational speeds were restricted to the

range (96% to 100%) permitted for the TPE331 engines. Actual

values for the torque were read from cockpit instruments; propeller rpm values were deduced from measured propeller blade passage

frequencies in the acoustic spectra.

The instruments in the cockpit of the test airplane did not permit

selection of specific relative phase angles between the two

propellers. Adjustment of the relative phase was provided simply

by means of a knob without a scale. Consequently, four arbitrary

settings were chosen whereby the knob position was identified as 9

o'clock, ii o'clock, 1 o'clock, and 3 o'clock. The full range of

adjustment for the knob was from 8 o'clock to 4 o'clock. Analysis

of the test data was used to provide an indication of the associated relative phase angles. (This analysis is discussed later in

the report). It is understood that the synchrophaser operates

with the starboard propeller as the slave of the port propeller.

In an attempt to overcome the uncertainty regarding the relative

phase setting, measurements were performed also when the two propellers were operated at different rotational speeds, but at the

-13-
same torque. The objective of the tests was to separate the

contributions from the two engines so that constructive or

destructive acoustic interference, which occurs in the cabin when

both propellers operate at the same speed, could be prevented.

The propeller speeds were selected to be the maximum (100%) and °

minimum (96%) values permited by the engine design. Propeller

torque was used as a controlling parameter rather than engine

power because only torque is indicated in the cockpit. As a consequence, the engines were at slightly different power settings,

as can be seen in Tables 2 through 5.

Outside air temperature was measured by means of cockpit

instrumentation. In addition, the cabin skin temperature was

measured on the fourth flight when the fiberglass batts were

installed. Values of the skin temperature are given in Table 6.

There are some small differences between the outside air and skin

temperatures, but these are probably calibration errors. In general, the results show that the skin temperature is approximately

equal to the outside air temperature, after allowing for a short

adjustment period.

All acoustic data were recorded during straight-and-level flight.

Flight through clouds was avoided and the flight conditions were

essentially "smooth" throughout the four flight tests. Four crew

members were present during each flight. They consisted of the

pilot, flight engineer (in copilot's seat) and two acoustic test

engineers seated in chairs close to microphone locations 2 and 3.

2.3 Instrumentation

During the flight test program measurements were made of the sound

pressure levels inside the cabin and the fluctuating pressures on

-14-
• TABLE 6

FUSELAGE SKIN TEMPERATURE MEASURED DURING FLIGHT #4

Condt. Time Flight Outside Skin

Ident. Altitude Air Temp Temperature

Hrs m/ft °F oF

Ground 1420 ..... 92

1 1448 3.4k/llk 46 52

3 1502 3.4k/llk 46 50

9 1511 4.6k/15k 32 35

i0 1518 4.6k/15k 32 36

12 1537 4.6k/15k 32 30

17 1544 8.5k/28k -16 -19

17 1547 8.5k/28k -16 -20

18 1550 8.5k/28k -16 -22

Ground 1620 --- 82 75

-15-
the exterior of the fuselage. Six fixed microphone locations were

selected inside the cabin. These locations are shown in Figure 4

and listed in Table 7. Photographs of some of the installed

microphones are shown in Figure 5. The locations were selected to

be similar to those used in earlier tests [9, 19]. Four of the

locations were on the starboard side of the cabin and two on the

port; all six microphones were positioned vertically at the

approximate ear level of a seated passenger. The microphones were

not moved until the end of flight #3 when they were removed to

allow for installation of the fiberglass treatment. The microphones were then reinstalled for the fourth flight.

Exterior fluctuating pressures were measured simultaneously on the

port and starboard sides of the fuselage using two condenser

microphones mounted without protective grids and with diaphragms

flush with the exterior surface of the skin panels, and two stickon pressure sensors. The locations are shown in Figure 4 and

listed in Table 8. Based on available drawings, it is estimated

that the flush-mounted microphones were about 5 cm (2 inches)

below the centers of the propeller spinners. Close-up views of

the installations are shown in Figure 6. Because of problems

encountered with data from the pressure sensors, only data from

the flush-mounted microphones are presented in this report.

The microphones used inside the cabin were Bruel and Kjaer Type

4155 0.5-inch prepolarized condenser microphones with windscreens.

The exterior flush-mounted microphones were B & K Type 4135 (port

side) or Type 4136 (starboard side), installed by means of B & K

Type UA 0122 Flexible Adaptors with flush mountings. The stick-on

pressure sensors were BBN Model 376 pressure sensors. All the

data were recorded simultaneously on a 14-track Honeywell Model

5600C tape recorder at a tape speed of 30 ips using FM record/

reproduce and IRIG Intermediate band (i0 kHz bandwidth).

-16-
- PROP PLANE

I

----_ ._____ ,,I J

I !11 I ,_,: _ _ ,'_

_CAL

Equipment ' LOCATION AT PASSENGER

I • EAR EXTERIOR LEVEL MICROPHONE

FIGURE 4. LOCATIONS OF MICROPHONES INSIDE CABIN AND ON EXTERIOR

OF FUSELAGE.

-]7-
TABLE 7

LOCATIONS OF CABIN MICROPHONES

Transducer Location* Station (Inches)

1 Copilot seat 60

2 Forward Passenger seat,

starboard 78

3 Propeller plane, starboard 117

4 Aft passenger seat, starboard 155

5 Aft passenger seat, port 155

6 Propeller plane, port 117

*All microphones at approximate ear height of a seated passenger.

Seats were present for the test program at locations i, 2, and 3

only. Location 6 was above the test instrumentation.

TABLE 8

LOCATIONS OF TRANSDUCERS ON FUSELAGE EXTERIOR

Transducer Location Station Waterline

(inches) (inches)

Flush Microphone

Port 7.5 cm (3 in.) forward of propeller

plane 114.5 -ii

Starboard 7.5 cm (3 in.) forward of propeller

plane 114.5 -ii "

Pressure Sensor

Port 1.3 cm (0.5 in.) aft

of propeller plane 117.5 -12

Starboard 2.8 cm (1.5 in.) aft

of propeller plane 118.5 -12

-18-
(a) Starboard Side of Cabin

(b) Port Side of Cabin

FIGURE 5. INTERIOR OF BARE CABIN SHOWING INSTALLED INSTRUMENTAION

-19-
O._..._ Flush-Mounted

_ Microphone

\

(a) Starboard Side of Fuselage

FIu sh-Mou nted__

Microphone _

(b) Port Side of Fuselage

FIGURE 6. EXTERNAL MICROPHONES AND PRESSURE SENSORS

-20-
Data reduction was performed in terms of narrowband spectra using

a Spectral Dynamics Model 360 Digital Signal Processor and in

terms of one-third octave band spectra using a GenRad Type 1921

one-third octave band analyzer. In order to provide adequate res-

• olution for the low-order harmonics of the blade passage frequency, the narrowband data reduction was performed first for the frequency range 0-500 Hz and then repeated for the range 0-i000 Hz.

Harmonic levels were obtained for the lower frequency range and

spectra plotted for the higher range. Where necessary, harmonic

levels were adjusted to remove the estimated broadband contribution at the harmonic frequencies.

2.4 Interior Confi@uration

The first three flight tests were conducted with a "bare" or

untreated interior. All acoustic and thermal treatments (fiberglass, interior trim, carpets, bulkhead covering, etc.) were

removed from the interior aft of Station 60.5, i.e. aft of the

pilot and copilot seats. Also, all dynamic absorbers, which are

installed in production aircraft [20] and tuned to the first

(fundamental) and second harmonics of the propeller blade passage

frequency, were removed. These absorbers were present in the previous flight test series [9, 19]. Four seats were installed in

the interior for all four flights. Three of the seats were close

to microphone locations, as is indicated in Figure 4.

Prior to the fourth flight, fiberglass batts were installed

throughout the cabin aft of Station 60.5. The batts were formed

" from Manville "Insul-Shield" Type 3 which has a density of 48

kg/cu.m (3 pcf). The material was unfaced and had a thickness of

5 cm (2 inches) on the sidewalls and 7.5 cm (3 inches) on the

cabin aft bulkhead. "Insul-Shield" consists of inorganic glass

fibers bonded with a thermosetting resin. It was selected for the

-21-
present test series because batts, cut to size, were immediately

available from a laboratory test rig at Gulfstream Aerospace Corp.

The objective was to add acoustic absorption to the interior

volume.

The narrow regions which surround cabin windows were not amenable

to treatment with Insul-Shield. In these cases, a treatment of AA

fiberglass with a thickness of 5 cm (2 inches) was used. There

was no sound-absorbing material on the cabin floor.

Sample batts of "Insul-Shield" material are shown in Figure 7(a),

and a sample fiberglass treatment to surround a window is shown in

Figure 7(b). Installed treatments are shown in Figure 8.

In addition, an acoustic barrier was installed between the cockpit

and the cabin. This barrier consisted of TNB-101 PSA Barrier and

a 2.5 cm (i inch) thick sheet of open-cell foam. The TNB-101

material was composed of a sheet of lead-impregnated vinyl which

was 0.25 cm (0.i inch) thick and a layer of foam which was 0.64 cm

(0.25 inch) thick. The outer face of the foam layer had an

adhesive surface which was used to attach the 2.5 cm sheet of

opencell foam. The surface density of the TNB-101 PSA Barrier was

4.94 kg/sq.m (i.01 psf), as measured by Gulfstream Aerospace.

The barrier was attached by cable ties to a horizontal crossbar

which was installed just aft of Station 69. The top edge of the

barrier was attached by ties to the fuselage frame at that

station. The fit between the barrier and fuselage structure was

not tight because of the presence of ducts, cables, etc., and

small gaps were observed during flight #4. However, time constraints did not permit improvements to the installation.

-22-
(a) InsuI-Shield Batts

(b) Window-Surround Treatment

FIGURE 7. SAMPLES OF SOUND-ABSORBING TREATMENTS

-23-
FIGURE 8. SOUND-ABSORBING MATERIAL INSTALLED IN CABIN

-24--
Furthermore, the acoustic leaks were probably insignificant since

the acoustic treatment in the cabin did not provide a high transmission loss through the fuselage sidewall. The barrier was cut

vertically at the mid-point to allow access to the cockpit; an

adequate overlap of material at this cut prevented an acoustic

leak. The barrier was installed such that the foam sheet was on

the cabin side of the bulkhead.

-25-
3.0 EXTERIOR FLUCTUATING PRESSURE FIELD

3.1 Narrowband Spectra

Typical narrowband spectra for the exterior fluctuating pressure

field are given in Figures 9 through 12. The data are associated

with flight #3 for conditions under which the two propellers were

operated at different rotational speeds, or under single-engine

operation. The spectra are presented for the frequency range

0-i000 Hz, but the plotted sound levels at frequencies above 800

Hz are attenuated by the anti-aliasing filters of the analyzer.

The spectra consist of a fairly uniform broadband level on which

is superimposed a series of discrete frequency components associated with harmonics of the propeller blade passage frequency. The

higher order harmonics are seen most strongly at the highest

flight altitude, which for this particular flight was 8,500 m or

28,000 ft (nominally 9,100 m or 30,000 ft). Since the propellers

were operating at different rotational speeds, their individual

contributions can be identified in the figures, except for the

fundamentals which merge together for this particular frequency

resolution. Relative magnitudes of the fundamental component can

be compared, however, in Figures ii and 12 which contain data for

single-engine operation. It is seen that, at a given location,

the sound levels generated by the adjacent propeller are 15 to 25

dB higher than the levels associated with the propeller on the

opposite side of the airplane. Harmonic sound pressure levels for

the port and starboard propeller are tabulated in Appendix A for

all four flights.

In some spectra, secondary peaks can be seen at harmonics of the

propeller shaft rotational frequency and at the fundamental rotational frequency of the engine turbine shaft. Propeller shaft

-26-
I

I ...

!

I

Predicted; Turbulent

Boundary Layer

I !

-j'

. - .--+---+-\ I . I • i .. ,:

.- 1-·

i

I...

! • j

,

I -i-

!

"'i

,

,. . -

,

i'

I I i

--f..---. ._.._-~- ._- . ! :

I

! ' .. ,

,

-- - 1

90

80

Starboard Propeller, 1570 rpm

70 I I I I i I :-..._......;.__......;.__......;.__~_.......;_"""-....:.. _ _J

120:

(a) Altitude 9,100 m (30,000 tt)

130 ~~~I:----,--:---:----r---rl--.----:'1:-.--------

Anti-Aliasing Port Propeller, 1520 rpm .- Filter

. r-;---t-+ ..._. 1_ _ _

! -r-·f---·,----- 110 .

It)

c..

I

o

b 100

E

o

N

Cll

:...

,

ai

>

Cll

...J

Cll

:..

•

400 600 800 1000

Frequency, Hz.

200

(b) Altitude 4,600 m (15,000 tt)

o

70

100

III

:D 130 ,..---:-----,----r---r----r-'--...,....--...,---..,---.,.--....... :... I j; : . I . I '

I ;

120 ~- -J----:-r:-- -------1' '-l~-j--T---.:·_-

'.--. ,-_' ._~--_. '-r-:--H::'--~---+~-I U . I.' 110 ' " U. :.;, Tu rb.one :. .. : - t,

, ! : I

~- - ~A I~ ~-11' --- ,~+-~ illhB~-: 90 ~__, .~.,._.

.:

i. w:i ~~;Ii"'\.. ,::,,:,,:, i '~"I~' v ' :"" -'- .=

i' I 'I i'

80 ;: . ,:. pred~t~d; :Turbulent Boundary Layer . ~ ---.

_:'-- -J-.- _~J~_ ! I '_~;;:.'f'

: ! in I I I

FIGURE 9. NARROWBAN 0 SPECTRA OF EXTERNAL FLUCTUAT ING PRESSU RE

FIELD MEASURED ON PORT SIDE OF FUSELAGE. (PROPELLERS

OPERATING AT DIFFERENT RPM)

-27-
(cl Altitude 3,000 m (10,000 ttl

.----.---- I i I

.... ;

I

, ; Predicted; Turbulent Boundary Layer

80 : I

I"--, 'fR-';' "1," 'R--- . tf' j ..... '1 -.-- ...... :,"

---~-j-i_- ; __J_ ! -- : I f

: I: i ' ! ! I I 7O....---:_-....;..-_..:-_-~..;...--:..__......_--_......._------.;.---

o 200 400 600 800 1000

Frequency, Hz.

110

100 ..-:

130 ,...---:-/~--:-~---:-~---r----:~-,..----:---..,....----:--~ ......

-,-- - --)-- --r-.. --l

i

,i I - ._~-.J--+---+--'--'-r~- ; I, "

I , .. i,. I :

: .! i , : I . ';' ... !.. \ 1 : \ l I,

T--' --I-- --r---l.-- , I ,

~'" i ... i . ',' Turbine j....

--:-- -+- - on:1JT.-r-+--1i---t-;--t--i-- I 'I '

: . !!!.... ..:. . -'-f"" -. -l ... I

" , l'v101''''\r\llt-.'V,...,.~ :_~ _.~ ~. __+__-+--;-l--+--

.-: --I-I

120

ttl·

0-

I

o

u

E

o

N

CU

co

"0

-ttl

:J

-

U

:J

u..

FIGURE 9. CONTINUEu

-28-
(a) Altitude 9, I00 m (30,000 ft)

130 } i :

Sta rboa rd A nti-Al ia sing

Filter

120 i

I _ i

,m •

i

110 Predicted; Turbulent ..

• _ Boundary Layer

O i

_" I00 ' . -..

90 ........... ._,__ . _.,_

_" \II! !

80 ..: Port Propeller i..................

..1 70

m (b) Altitude 4,600 m (15,000 ft)

130

_ t._!............ i. ___i__. ..... ' ..............

.... I---I I : i , _ !_ ;

2 11o ......... . .......... £ ......................................................

90 . _........... _ .m

! !" edicted'_ry La_,er' _._r_l_

70

• 0 200 400 600 800 I000

- Frequency, Hz.

FIGURE 10. NARROWBAND SPECTRA OF EXTERNAL FLUCTUATING PRESSURE

FIELD MEASURED ON STARBOARD SIDE OF FUSELAGE.

(PROPELLERS OPERATING AT DIFFERENT RPM)

-29-
D.

I

o

u (c) Altitude 3,000 m (10,000 ft) om

E 130 , :

_" 120

en

..: 110

>

aJ

L 100

OJ

0. 90

r"

om

80

U

LL

70

0 200 400 600 800 1000

Frequency, Hz.

FIGURE 10. CONTINUED

_ -30-
(a) Port Engine Operating Alone

I '

- 110 _.. ' .i

Predicted; Turbulent

• n

Boundary Layer

o -!

_- 100 --

E

_ J

u_ 90 t

L

I

-o 80 --t

I

>

-J 70

(b) Starboard Engine Operating Alone

130

• 1 1

U ' i

--_ 110 ] !

LI. I '

Predicted; Turbulent -----

_oo............. i!i_-...... i, ........ ......... ,_ounOa_ _o_

90 ___ _ _ _ _-_- ....

• '• ;

80 .........

70

0 200 400 600 800 I000

" Frequency, Hz.

FIGURE 11, NARROWBAND SPECTRA OF EXTERNAL FLUCTUATING i_RESSURE

FIELD MEASURED ON PORT SIDE OF FUSELAGE DURING SINGLEENGINE OPERATION

-31-
400 600 800 1000

Frequency, Hz.

200

(al Starboard Engine Operating Alone

o

90

80

70

90

80

130 r---~--~---:--:---'---:--""-~--r-~-r-~--- _

r-+"r: '. J-

'

--1-.1-,-1 ... -- --' -[.,- "".--. ,'.'- .j

I .. ~. \ .. ' 1 ..... j .. - .••• "'1 .•__ ..•_ •.••- .•.. ·_·jl··-' .~- .:.- :--1--··· '~"j'" I .: ."1

~lI,~- , .1=1i.-,-, ,- \-~-I--

I IT

-- ---,-' ,-

rt=~-+--+ ..f Ell F ..J.--....+....., _'-+-'.~+ill_.'+-~--l'~I'-";'_-:'+-"_-T+-l_"'1

...1:" Predicted; Turbulent,,~,I!.. __ ,._,,~,i, .•.• 1\ ... ! i Boundary Layer .] \

~--J--,...-!l "i -n-rr ' t\ t7 0 L.-_--!_..:...---!..~_~.....:.._:...__:__..:.._;....._:___.:.........:.........:._~_:....:...____

120

110

100

.

rc

a.

I

o

b 100

E

,

1)

>

Q)

-l

Q)

::::l

130 ~(b...:l:......,P...;:o_r_t_E_n..:g~i.:..:n.:.e_O:..p~er...:a...:t:.:..i n:.:..g::....:.A.:.I..:o.:.n..:e......._~__--:-_....... ......,

: I i

i ' r-r-r--

B-t-·

120 _, -.... : . ; · .. 1··.. : I .. j '1' ; ..

110:-\: I '1' II· i --~., '

: 1 .,. '-"li

1_

.-.. ·· ..i-I 1

!

:- 1-++ I! I

----; '" ,V""I-., ' ,I : '\ I I 1 ,... ',",-""".n.. i....... .• : I I

'j~~-I"n"" - I . -k '---r" . J i ' I I ; "1..1

! '\.; I I 1 : : 1\ .;. -1 Predicted; T u rbuJ ent ~ou7dary LaYi" T" .... i\

--:-+-+--+-i-l--'-+- 1,1 --+---.;'---+-+j----J-. "j 1 ;'-" I ill I." I\.. ,

FIGURE 12. NARROWBAND SPECTRA OF EXTERNAL FLUCTUATING PRF.SSURF.

FIELD MEASURED ON STARBOARD SIDE OF FUSELAGE DURING

SINGLE-ENGINE OPERATION

-32-
harmonics are more evident in data measured on the port side than

on the starboard side. The components may be associated with a

: slight difference between different blades of the propeller. On

the other hand, both the propeller shaft and engine turbine con-

" tributions may result from structureborne noise transmission via

the engine mounts.

The broadband levels in the spectra appear to vary with aircraft

speed. For example, when spectra measured at the starboard location at an altitude of 4,600 m are compared for two- and oneengine operation (Figures 10(b) and 12(a)) it is seen that the

broadband levels differ by 4 to 5 dB. The lower levels are associated with the lower aircraft speeds during single-engine

operation. These broadband levels can be attributed to the fluctuating pressure field of the turbulent boundary layer, as is

discussed later.

3.2 Harmonic Data Variability

One important objective of the flight test program was the

investigation of data variability for harmonic levels associated

with the propeller noise. For this reason, three similar flights

were performed for the untreated cabin configuration, then a

fourth flight was conducted with a partially treated interior.

Since there were no changes to the external configuration of the

airplane, data from all four flights could be considered together.

However, data from flight #4 will be considered separately, in

order to assist in evaluating the effect of the fiberglass treatment on the cabin sound levels.

For this analysis data measured by a given flush-mounted

microphone were investigated with regard to the sound levels generated by the propeller adjacent to that microphone. It has been

-33-
shown earlier that, when propellers are operating at different

rpm, the harmonic levels on one side of the fuselage are dominated

by the propeller on that side of the airplane. Thus, it can be

assumed that, when two propellers are operating at the same rpm,

the sound levels measured by a given flush-mounted microphone are

dominated by the adjacent propeller. Under this assumption, it is

possible to obtain five test points for low propeller rpm conditions at 4600 m (15000 ft) and five points at 9100 m (30,000 ft)

nominal altitudes (except for flight #4 when there was a malfunction of the synchrophaser). Flight test conditions for singleand twin-engine operation were sufficiently different that singleengine operation data for 4600 m altitude were excluded from the

data set. One test point for high rpm conditions was available

for 4600 m and 9100 m altitudes from each flight. For the 3000 m

(i0,000 ft) altitude operation two test points were available for

both low and high rpm operation.

The ranges of harmonic levels for each test condition and each

side of the fuselage are shown in Figures 13 through 16. The

figures show the upper and lower bounds for the harmonic levels,

irrespective of flight and test conditions for the first three

flights. Inspection of the data shows that the variability of

harmonic level for the starboard propeller is generally less than

that for the port propeller. When averaged over all harmonics and

all test conditions the harmonic level average variability or data

range was 3 dB (or + 1.5 dB) at the starboard measurement location

and 5 dB (or + 2.5 dB) at the port location. Data from flight #4

are superimposed on the data ranges for flights 1 through 3. It

is seen that, in general, data from flight #4 are within the range

for the preceding flights, although in some cases they lie at, or .

close to, the upper bound. This is true particularly of the port

propeller.

I

_ "i -34-
130

J! I Flights 1 - 3

120 !

I OA Flight 4

..

1 .

I I I 110

1I ltI

Cl.

I

0

100 u

E

0

N _ (a) Altitude 9, 100 m

aJ

co 90

""0 2 3 4 5 6 7 8 9 10

.

1j

>

rI aJ

...J 130

aJ 0

I ::J

til

til 0 aJ I a.

120 "0 r c: 0 ::J

I 0

Vl

110 I I I I 100

(b) Altitude 4,600 m

90

1 2 3 4 5 6 7 8 9 10

. Harmonic Order -

FIGURE 13. VARIABILITY OF HARMONIC SOUND LEVELS ON EXTERI0R OF

FUSELAGE. (COMPONENT FROM NEAREST PROPELLEF<, PORT

SIDE, LOW RPM)

-35-
140

o

O

O. 130 - O ---=---Flinhts1 - 3

O

.__u O O_ Flight 4

E

°

120 - 0

II1

_ _o

" I

110 • " O

_ 0

ffl

• 100 -

L 0

-_r" O (c) Altitude 3,000 m I

U3

90 I I I I J I I I I I

I 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 13. CONTINUED

-36-
130 -

120 - I" O Flight 4

t .L

s. I00

._

U m

E

(a) Altitude 9, I00 m

rn 90 I ! t I I I l I I I

"D I 2 3 4 5 6 7 8 9 10

> O O

v 130-I I O

._ 120 - T

ri

100 -

(b) Altitude 4,600 m

90 l t _ l t t , _ l l

I 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 14. VARIABILITY OF HARMONIC SOUND LEVELS ON EXTERIOR OF

FUSELAGE. (COMPONENT FROM NEAREST PROPELLER, PORT

SIDE, HIGH RPM)

-37-
140

0 0

ltl 130 ! t 0

I c. ! I Flights 1 - 3

0 0

u OA Flight 4

E

! 0 0 N

120 1 al 0

I co 0 "0

I , 0

Qj 110 I >

al 0

..J I al 0

r :J

1Il

1Il

al 100

C.

"0

c ( c) Altitude 3,000 m

:J

0

V)

90

1 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 14. CONTINUED

-38-
130

! I I Flight 1 - 3

" • 120 I OA Flight 4 .

J

110 1 I

ttl I I 0-

I

I 0

I- 100 u

E

0

N (a) Altitude 9,100 m

QJ

ICD 90

1J 2 3 4 5 6 7 8 9 10

,

Qj

>

QJ

...J 130 1 QJ

l- I :J

VI

VI

Cl)

l- I Q.

'0 120

c::

:J I

0

Vl

110 f

t

100 r

r (b) Altitude 4,600 m

.. T

90

.. 1 2 3 4 5 6 7 8 9 10 - Harmonic Order

FIGURE 15. VARIABILITY OF HARMONIC SOUND LEVELS ON EXTERIOR OF

FUSELAGE. (COMPONENT FROM NEAREST PROPELLER, STARBOARD

SlOE, LOW RPM)

-39-
140

130 mid

I "

Flights 1 - 3

I

"_ O& Flight 4

°120 - t

L

110 > ,,

Q)

L

• loo -

0.

"O¢-{c} Altitude 3,000 m

O

U3

90 I , I I t _I I I J I t

I 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 15. CONTINUED

-40-
130

! ! I Flights 1 - 3

!

120 :Q 0 Flight 4

0:

aa:

I

0

I no

&

III

c.

I !

0

100 u

E

0 (a) Altitude 9,100 m N

aJ

co 90

"0 1 2 3 4 5 6 7 8 9 10

Qj

>

aJ

-J 130

aJ

:J

til

til

aJ

C. t

"0 120

c:

:J ! 0

V)

110 !

i

0

I

100 ! 0

(b) Altitude 4,600 m 1:

90

1 2 3 4 5 6 7 8 9 10

. Harmonic Order .,

FIGURE 16. VARIABILITY OF HARMONIC SOUND LEVELS ON EXTERIOR OF

FUSELAGE. (COMPONENT FROM NEAREST PROPELLER, STARBOARD

SIDE, HIGH RPM)

-41-
140 "

_. 130 - T

_ .L Flights I - 3

o I

.--. 0 A Flight 4

E

°

120 - If

c>u 110 - 0 o 0

° II-°

.J

L

to 100 -

"o (c) Altitude 3,000 m

o

u_

90 - I I I ! J I I I J

I 2 3 4 5 6 7 8 9 10

Harmonic Order

o

FIGURE 16. CONTINUED

-42-
3.3 Comparison of Port and Starboard Levels

A comparison of the measured data ranges shown in Figures 13

through 16 indicates that the harmonic sound pressure levels on

. the port side of the fuselage are equal to, or greater than, those

on the starboard side. Such a comparison, taken from data in

Figures 13 and 15 for low propeller rpm conditions is shown in

Figure 17.

At a nominal altitude of 9,100 m (30,000 ft) the harmonic sound

pressure levels for the port and starboard propellers at low rpm

are similar in value, as shown in Figure 17(a). Overall sound

pressure levels, obtained by summing over the ten lowest-order

harmonics, range from 127.2 dB to 131.8 dB for the port propeller

and 128.8 to 131.2 dB for the starboard propeller. At a nominal

altitude of 4,600 m (15,000 ft) the test data show that the harmonic sound pressure levels are significantly higher for the port

propeller than for the starboard. This comparison is shown in

Figure 17(b); overall sound pressure levels now lie in the range

of 132.1 dB to 136.2 dB for the port propeller and 129.4 dB to

132.7 dB for the starboard. Similar trends can be found in the

data associated with the high rotational speed of the propeller.

Also, results for an altitude of 3,000 m are similar to those for

4,600 m. A comparison of overall sound pressure levels is given

in Table 9.

When the data are compared with previous results a similar trend

can be found. In the previous test, overall sound pressure levels

[ for port and starboard propellers (again computed by summing the

harmonic contributions) differed by about 1 dB at an altitude of

: 8,800 m and by 2.5 to 6.1 dB at 4,600 m, with the port propeller

being associated with the higher sound pressure levels.

-43-
130 -

-_L _ _-"r I starb°ard I q T 7-

120 - JL t Port

,,L

•J. T .-

_ T

' I

._ 100 -

E

e_ (a) Altitude 9, 100 m

¢J

cO 90 t I w I I I I I I I

"O

I 2 3 4 5 6 7 8 9 10

_J

>

.a_ 130 - _ il

_- T

• T

_- [ ' -o 120 - _- T

o ,

m i

I TI

110 - ! T

I

I

,,L 3" [ ,I

I

100 - T J" 1",

/

I

-[' (b) Altitude 4,600 m _-

T

90 i I I I I I I I i t -

1 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 17. COMPARISON OF RANGE OF HARMONIC SOUND PRESSURE LEVELS

GENERATED BY PORT AND STARBOARD PROPELLERS. (FLIGHTS I-4)

-44-
_& p 4

TABLE 9

MEASURED AND PREDICTEDEXTERIOR OVERALL SOUND PRESSURE

LEVELS ASSOCIATEDWITH PROPELLERDISCRETE FREQUENCY SOUND

Overall Sound Pressure Level** dB re 20 micro Pa

Airplane No. of Prop

Altitude Engines RPM Predicted* Measured

m (ft) [21] [22] Port Starboard

I 3,000 (lO,O00) 2 LOW 144.1 139.5 132.2-138.2 131.0-133.1

I 2 High 144.4 140.0 133.5-138.5 130.8-132.9

4,600 (15,000) 2 LOW 144.3 139.9 132.1-136.2 129.4-132.7

2 High 144.4 140.4 133.0-136.3 129.9-132.5

4,600 (15,000) 1 LOW 144.1/ 139.6/ 128.2-133.0 130.2-132.2

143.7 139.2

9,100 (30,000) 2 LOW 141.9 137.5 127.2-131.8 128.8-131.2

2 High 142.2 138.0 128.5-131.9 129.8-131.8

* Port/Starboard

** Computed as an energy sum of harmonic components for harmonic orders 1 through I0.
3.4 Comparison with Simplified Predictions

Two simplified prediction procedures [21, 22] are available for .i

estimating propeller-induced fluctuating pressure levels on the

fuselage exterior. Both procedures are essentially empirical in °

nature and rely on fairly rudimentary descriptions of the propeller performance. They require significantly less detailed information regarding the propeller than do the analytical models that

have been developed recently.

The two methods [21, 22] have been used previously to compare with

measured pressure levels on an early piston-engine Commander airplane operating under static and taxi conditions [15-18]. In that

study it was found that the SAE procedure [21] was the more accurate under static conditions, but the method described in Ref. 22

became the more reliable method when the airplane had forward

motion. Both procedures have been applied to the present test

airplane in an earlier investigation and are being applied again

to the present data.

First, the overall sound pressure levels can be compared. In the

case of the test data, these levels are obtained by an energy sum

of the harmonic components for harmonics 1 through i0. Prediction

of the overall levels requires a knowledge of propeller tip rotational and helical Mach numbers, propeller power, diameter and

number of blades, and the location of the observation point.

These input data values are available immediately with the exception of the propeller power. This was estimated using the simple

relationship between power, rpm and torque, and the assumption

that 100% torque was associated with 820 shp at maximum rpm.

A comparison of measured and predicted overall sound pressure

levels is given in Table 9 where it is seen that both prediction

i -46- !
procedures over-estimate the measured levels. The largest

discrepancies occur when the SAE procedure [21] is used. On an

average, the method over-estimates the overall sound pressure levels by about ii dB. The second procedure [22] overestimates the

measured levels by, on the average, 7 dB. These discrepancies are

similar to those of a previous test where average differences of 8

dB and 4 dB, respectively, were observed.

Because of the differences between measured and predicted overall

sound pressure levels, the comparison of harmonic levels can be

done most conveniently when the levels are expressed relative to

overall values. Differences in overall levels are then removed

from the discussion. Comparisons in this basis are given in

Figures 18 through 21.

Comparing first the measured data for the port and starboard

propeller, it is seen that the port propeller generally has the

higher normalized harmonic sound levels at an altitude of 3,000 m

and the lower levels at 9,100 m. At the intermediate altitude of

4,600 m the measured normalized sound levels are similar for the

port and starboard propellers.

The prediction procedures do not differentiate between clockwise

and counter-clockwise directions of rotation. Thus, a single

curve is given for both port and starboard propellers. When predicted and measured sound pressure levels are compared, it is seen

that the measured levels generally lie between the two predicted

curves, but they tend to be closer in value to the results using

- Ref. 22 than to the SAE method [21] at all harmonic orders. This

result is slightly different from that of a previous test program

where the measured normalized harmonic levels tended to follow the

predictions of Ref. 22.

-47-
: Measured :

0 " I Starboard

, Port

,J_

 eo, teo:

-I0- --o-- Ref. 21

---O--- Ref. 22

"_

-20 - ,_, .

"r

Nix _r I

O

(a) Low RPM "II +

m -40 i I I I I I I I I

-_ I 2 3 4 5 6 7 8 9 10

_i 0 -

°

+ \

I_\'_._.

=o

I/I

0 i-i i

-30 " 0

(b) High RPM T, J.

-40 i I I I I I I I t

I 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 18. COMPARISON OF MEASURED AND PREDICTED PROPELLER HARMONIC

SOUND PRESSURE LEVELS: 3,000 m ALTITUDE.

P

+ -48-
0 " Measured:

• _ Starboard

-10 - Predicted.

, _ "-- "Ref. 21

• .__--O-- Ref. 22

-2o- \ _[ •

\ ,

0 '

\l "

% i

!

-- -30 - O I "r

-- I

I1_ I

L

° [

• (a) Low RPM ;"

O

QJ

s. I I I I I I I I I I

m -40

"o I 2 3 4 5 6 7 8 9 10

cJ

._1 0 -

°m _

n. -10 -

o _e

m \i -

0 °

-20 - \ -

\ I T

\ '

oN _ r

!

\

, [ T -30 " ' r

t -

(b) High RPM I

I I I I I J I I I I

" -40

I 2 3 4 5 6 7 8 9 10

Harmonic Order

i

FIGURE 19. COMPARISON OF MEASURED AND PREDICTED PHOPELLER HARMONIC

SOUND PRESSURE LEVELS: 4,600 m ALTITUDE, TWO-ENGINE

OPERATION.

-49-
Measu red :

0 - "I" Starboard .

• !

"_ Port

> __ Predicted :Ref.

O -10 --

-- --- 21

_" ,___._ ----O---- Ref. 22

"13

-20 - "_ t --.._...___,

o \

' \g

L 0

-30 - %

€- _,

!

u_ -40 -- , ,

m --

-50 I I I I I I I I I I

I 2 3 4 5 6 7 8 9 10

Harmonic Urder

FIGURE 20. COMPARISON OF MEASURED AND PREDICTED PROPELLER HARMONIC "

SOUND PRESSURE LEVELS: 4,600 m ALTITUDE, SINGLE-ENGINE

OPERATION.
Measured ;

I Starboard

0 " T

Port

Predicted :

_. --"-- Ref. 21

- I 0 - _-_,.,_., -- - O-- - Ref. 22

,\ -I" _.

N I --

-30 - -o

• (a) Low RPM

O

_- I I t I I I I I I I

m -40

"o I 2 3 4 5 6 7 8 9 10

GJ

0J --I 0 -

0J

D

_" -10 - _'_.

-k I _-_

=o k_ £

\ _w I

-20 - \ O _- I

\ T [ 1

NO -, i

I

- T

-30 -

(b) High RPM

• -40 I I I I I J I I i i

- I 2 3 4 5 6 7 8 9 10

Harmonic Order

o

FIGURE 21. COMPARISON OF MEASURED AND PREDICTED PROPELLER HARMONIC

SOUND PRESSURE LEVELS: 9,100 m ALTITUDE.

-5i-
3.5 Relative Phase

When the two propellers were operated under control of the

synchrophaser it was possible (except for flight #4) to adjust the

relative phase between the two propellers. This was accomplished

by adjustment of a knob on the pilot control panel, but there was

no indication of the actual phase setting. Consequently, an [

attempt was made to measure the relative phase using the pressure

signals recorded by the two flush mounted microphones.

Figure 22 compares simultaneous segments from pressure time

histories measured by the port and starboard flush-mounted microphones during condition 7 of flight #3. The time histories show

the repetitive pressure pulses associated with the passage of the

propeller blades, but superimposed on these patterns is random

noise. This noise complicates the measurement of time differences

between pulses of the two time histories. The random component

can be removed by time averaging of the pressure signals, as was

done by Piersol, et al [16] or by cross-correlation techniques.

The latter approach is possible because of the periodic

deterministic character of the pressure signatures generated by

the two propellers. Figure 23 shows how the irregularities in the

pressure time histories are smoothed out by the averaging involved

in the cross-correlation process.

The relative phase between the two propellers can now be determined from the time delay to the peak in the cross-correlation

function. For present purposes the peak used is that closest to

zero time delay. If T1 is the time delay to the correlation maximum closest to the origin, and Tm is the time delay between adjacent maxima (Tm = i/fb, where fb is the propeller blade

-52-
,. I • .. • t

(a) Port Propeller

c.

E

«

(1)

l-

:J

III

III

(1)

la.

--

-<1.'

"'

U

(J)

>- l-

"'

l-

-e (b) Starboard Propeller

«

I

U1

Cfl

I

t- 10 second~

Time

FIGURE 22. TYPICAL PROPELLER PRESSURE TIME HISTORIES MEASURED ON

EXTERIOR OF FUSELAGE.
I I I I I

I

I

!

Time History l

Port Propeller

8 .

t

.D

<

o

u

omo

L

o

u

C ross-Correlation

o Function

U

o !

o ! \

,, / /

_ / \

E

<

t

Time History

Starboard Propeller

I I I I I

- 5 -10 -5 0 5 10 5

Time, Seconds

FIGURE 23, COMPARISON OF PROPELLER PRESSURE TIME HISTORIES AND CROSS

CORRELATION FUNCTION FOR THE TWO SIGNALS,

-5_-
passage frequency), then the relative phase between the two

propellers is given by

= -- x 360 degrees T

m

Resulting values for the relative phase angle are given in Table

i0 for test conditions from the first three flights. Data for the

one test condition for which propellers were operated at the same

rpm during the fourth flight (identified as condition 13 in Table

5) showed that the synchrophaser was not engaged and the relative

phase between the two propellers was drifting out of control.

Inspection of the data in Table i0 for test conditions 5 through 8

(airplane nominal altitude of 4,600 m or 15,000 ft) shows that

there is reasonable consistency, with phase repeatability from

flight to flight of about _ i0 degrees. In contrast, the data for

test conditions 13 through 16 (altitude of 9,200 m) show inconsistencies among themselves and when compared to data for an altitude

of 4,600 m. For example, phase angles measured for conditions 13

and 14 of flight #2 differ from corresponding values for flights

#i and #3. Also, phase angles for similar nominal settings of the

pilot's control knob (e.g. test conditions 5 and 13) have different values at 4,600 m and 9,200 m altitudes*

*Subsequent discussions with the manufacturer of the synchrophaser

indicate that the phse angle data are not as inconsistent as first

thought. The synchrophaser on the test airplane had a stability

of about +12 ° and the phase difference for a given setting of the

selector knob would depend on propeller rpm and torque. Since

+ there are differences in rpm and torque between conditions 5-8 and

" 13-16, the relative phase would also show differences.

Furthermore, for conditions 13-16, propeller rpm had similar

° values for flights 1 and 2, but different values for flight 3;

this pattern appears in the relative phase values in Table i0.

-55-
TABLE l0

RELATIVE PHASE BETWEEN PORT AND STARBOARD PROPELLERS

Flight 1 2 3 Average .

Condt. Ident Relative Phase (degrees)* Phase (deg[

5 --- +12 -7 +3 _i0

6 --- +99 +iii +105 _6

7 -149 -148 -136 -144 _7

8 -25 -17 -24 -22 _4

13 -118 +152 -84

14 -i0 -133 +4

15 --- +17 +127

16 --- +i16 -114

*Relative phase expressed within range _+ 180 °• Positive sign

indicates that port propeller leads the starboard propeller,

negative sign indicates that port propeller lags.

3.6 Turbulent Boundary Layer

The turbulent boundary layer on the exterior of the fuselage will

generate random pressure fluctuations which will appear as broadband noise in the signals from the flush-mounted microphones.

Thus, it is of interest to compare the broadband components in the

exterior fluctuating pressure spectra with predicted contributions

from the boundary layer. The prediction method used is an empiri- °

cal procedure based on measurements made on a Boeing 737 airplane .

[23]. The method was found to give good agreement with test data

-56-
from large aircraft and from wind tunnel tests, where the

turbulent boundary layer is well established. In the present

case, it is possible that the external flow at the measurement

" location could be influenced by upstream disturbances associated

with flow around the windshield or by flow on the neighborhood of

the wing/fuselage junction. The prediction procedure assumes an

idealized condition of flow over a flat plate with zero pressure

gradient. It was found, however, that alternating regions of

adverse and favorable pressure gradients, such as occur, for example, along the fuselage of a Boeing 737 have a negligible influence on the fluctuating pressure field.

Predicted broadband spectrum levels associated with the turbulent

boundary layer are superimposed on measured data from flight #3 in

Figures 9 through 12. It is seen that the predicted and measured

levels are in close agreement, with the slope of the predicted

spectra being slightly less than that of the measurements. Where

differences exist between measurements and predictions, no general

trend can be found, the predictions sometimes being higher than

the measurements and sometimes lower. Thus, it seems reasonable

to conclude that the measured broadband pressure fluctuations are

due to the turbulent boundary layer on the exterior of the fuselage and that the data show a variability of + 1 dB to D+ 2 dB.

3.7 One-Third Octave Band Spectra

One-third octave band spectra for the exterior pressure field are

listed in Appendix D for Flights 3 and 4. The spectra are presented for the frequency range 25 to 5000 Hz. Typical spectra are

" shown in Figure 24; these spectra correspond to narrowband spectra

presented in Figures 9 and i0. Since the spectrum levels at frequencies below about 800 Hz are dominated by discrete frequency,

components associated with the propeller blade passage frequency,

-57-
-[Z

_ZStarboard (Condt. 17) _

Yl f/ I '

120 i _ _ ,

m j_ _, _J _ /z \',,. --. Port (Condt. 18) --4-- -

7 | d 'II I_'_ b

7"

I I' I q _'. / -- I 1 ! ' ---- _- J I d _,'./

U ! f I _-

•- • I i ? N_. ,

o 110 _ i,

!

I/ _ ,'-"

" ".... _-_,ZPredicted; Turbulent

> " l-Boundary Layer , I

° " I I

" '" t I

_- 90 (a) Altitude 9,100m; Low rpm .._

L

ro= 130 1 _" Port (Condt. 10) ]

n_\ //-- - I

II I IE\

"_ I" i l,,\\ l\. --

_"ro Lfl ,_ _,l l'_ ,\ / _\ . Starboard (Condt • 9)---

n_ 120 il i r, ,'-

I,J I J ..... -,_ ,

I l _---"-_ _ _

"O 110 ,

•- ]

(-' -" "I _- " N 1 ]

O 100 / Predicted; Turbulent I

+ --Boundary Layer

, _ I I !

--(b) Altitude 4,600m; Low rpm -

90 ---, , , l l , l , , ) l l , ,

_o 63 )oo _o _o 400 630 _oo _6oo z_oo _ooo _3oo

sL_ _o _o _z_ zoo 3)_ _oo ooo _z_ozooo 3_o _ooo eooo

One-Third Octave Band Center Frequency, Hz

FIGURE 24. COMPARISON OF MEASURED EXTERIOR ONE-THIRD OCTAVE BAND

PRESSURE SPECTRA AND PREDICTED TURBULENT BOUNDARY LAYER

PRESSURE LEVELS.

-58-
the one-third octave band spectra are probably of most interest at

higher frequencies.

Superimposed on the measured spectra are predicted one-third

octave band levels for turbulent boundary layer pressure

" fluctuations. The agreement between measured and predicted levels

• does not seem to be as good as it was for the narrowband spectra.

At low frequencies, the apparent discrepancy is due to the

dominance of propeller noise in determining one-third octave band

levels. At high frequencies, the discrepancy could be associated

with the effect of transducer size; the finite size of the

microphone diaphragm results in reduced response to high frequency

(high wavenumber) pressure components. A more-detailed analysis

would require allowance for transducer size, but such analysis is

outside the scope of this study.

-59-
4.0 SOUND LEVELS IN UNTREATED CABIN

4.1 Narrowband Spectra o

The main frequency characteristics of the sound field in the

untreated cabin can be seen in Figure 25 which is associated with

both propellers operating at the same speed. The spectrum is dominated by discrete frequency components at multiples of the propeller blade passage frequency. Secondary peaks occur at multiples of the shaft rotational frequency (which is one-third of the

blade passage frequency) and at the turbine shaft rotational

frequency. These secondary peaks are, perhaps, more in evidence

than is the case for the exterior pressure field. Sound pressure

levels at harmonics of the blade passage frequency are listed in

Appendix B for all test conditions and for the ten lowest order

harmonics (where present).

Inspection of the propeller harmonic components shows that the

associated sound levels vary irregularly with frequency or harmonic order. This is in contrast to the exterior pressure measurements (see, for example, Figures 9 through 12) where the sound

levels generally decrease monotonically as frequency increases.

As might be expected, the transfer function introduced by the

fuselage structure and cabin volume changes markedly with

frequency.

The effect of the transfer function can be seen also in the

broadband sound pressure levels. The relatively uniform broadband

levels seen in Figure 9 through 12 becomes a very irregular pat- o

tern in the cabin sound level spectra. This is due, at least in

part, to structural and acoustic resonances.
<

_" 120

_,O fb= Blade Passage Frequency U

-- 110 - fs = Propeller Shaft Rotational Frequency

o fb 2fb ft = Turbine Shaft Rotational Frequency

LLI

m_" 100 6fb

"o 4fb

ILl 3fb 5fb 7fb

> 90

w 8fb

w 10fb

80 ft9fb •

II)

,,, 1

r¢

a. 7o

z

o 60 I I I I I I

I/I

0 100 200 300 400 500 600 700 800

FREQUENCY, HZ

FIGURE 25. TYPICAL NARROWBAND SOUND PRESSURE SPECTRUM MEASURED IN

; UNTREATED CAB IN.

-61 -
Narrowband acoustic spectra associated with operation of the two

propellers at different rotational speeds are given in Figures 26

and 27 for two nominal flight altitudes. In one case (Figure 26)

the port propeller is at low rpm and the starboard propeller at

high rpm; in the other case (Figure 27) the converse is true. As

was the case for the exterior pressure field, the cabin acoustic

spectra show more harmonic content at the higher flight altitude.

Cabin acoustic spectra associated with single-engine operation are

shown in Figure 28. The spectra are shown for two conditions,

with a strong turbine component present in both cases.

4.2 Harmonic Data Varibility

An analysis of the variability of harmonic sound pressure levels

measured inside the cabin is more complicated than for the exterior pressure field. There are several possible reasons for the

complications, one of them being the constructive and destructive

interference between acoustic signals from the two propellers.

To illustrate the magnitude of the data variability, harmonic

sound pressure levels have been compared for several repeated

flight conditions. This is done first (Figures 29 and 30) for

flight conditions 9 and i0, where the propellers were operated at

different rotational speeds at an altitude of 4600 m (15000 ft)

and the cabin was untreated. Two cabin microphones (#3 and #6)

are considered, these microphones being approximately in the plane

of rotation of the propellers and about half-way along the cabin.

The figures present data for the port and starboard propellers at

both low and high rpm conditions. It is not the intent of these

figures to compare port and starboard propeller components,

although some large differences can be seen. Rather, the intent

is to show the data variability for either the port or starboard

propeller when considered separately.

-62-
(a) Altitude 9,100 m

110 ,... :::, '''' .:".. ,. : . : . ':.: : ;; :.:' ..:: . ., ;

(b) Altitude 4,600 m

110 ,..:.;.:.:...:.:;.:.,~., :.:.~~~~---:-:---:--~~-;-~~~-.. ~.~':--;I---'

I

. . ....

.. . , .. "" ,

... ..,.

jj :L:-~ ;jL

::;: :::;: "

: .:!; I'" :::: :;; . ,. ..:. :;.. ,. t' ..

4_ -:-:-:1+---+-:-:;-1:~;: -~ 8~ :~~ ~fH ~~_: . ... ::! t':; . " 11' , ..

'. I:., ',,:

.; il I, , iii, . '1!' .

.. , ,

" "'1 : I .,.. I""'"

" .. ,"'; ... e :-.:. ~:+ ~;-.:...; ~+ ~~:~ .~:. :.. ~~ -:- ;..:. " : : i." ::: !" . :. ::.: : :J' :,: :,: j .••• , r ., •• ,.'••••.

,i:

;~~ T'"'-4~~ •• ,

;, ,I

::; ...!.,

. i

'i

~.-

::; :.

,.

,,

., .. ::: ::,; .. "! ::l;

. :....:..;. .:..:.~~~;. ::.. ;~~. ••••• , I, •• ';" I' , ,.

;:1) ; :; ;:;: l::: ::;:

I.,. ___"'-4-'-H-l :.n

. :111

• 'f,

i

100 ~.

90 -, .

i

:

80 ,,

1 100-.... , . ..:..:.~~ ~" ...:..... : ~- ...- .. :. .....:.. .. ,...c: .:.; ...,.~ ~,~ .~.- .... :~ _. .....:~~ •. :I

I-:.··...:+-'~,.~."4'~.F'+''-:-:t'~."-r-+~'--.--+-r-t~·'·r":~::~,.~"'~:-'-1::;B--

90 .~~.J_..' ,:' ... ... ,.. .. .,,, ,>... . :

----t - -- '~'~F'~: ~::-.:.~:~~~.:..: ,...c~~.:.:-~:~~ '~-f-;--~t--!-.--:.. -:-._ .. , , . . .

co

"0

.

nJ

a.

I

o

l0-

U

E

o

N

Q)

loow

>

Q)

-J

Q)

lo-

:3

III

III

Q)

l0-

a.

"0

I:

:3

o

V)

200 400 600

Frequency, Hz.

800 1000

FIGURE 26. NARROWBAND SPECTRA OF CAB IN SOUN D PRESSURE LEVELS AT

LOCATION 3; PORT PROPELLER, LOW RPM; STARBOARD PROPELLER,

HIGH RPM.

-63-
(a) Altitude 9,100 m

11o :i.i:s!_:_..:• ......, :,. i :..... :"_....: ii __ i ' k.

I

':'i ........... , .......... 1, , ..: ..... I . .I. " ', '

...................... l.t,, ',.t., ,; ...... ' ....

: ..... ........... f ....... q

i 80 - ............. o

L

U ..... • ..

•_ i h_ 4 :'i_ _ _I_,_li_ii!ili_ ....

L

m 60_ ' :::: i-;: -

> 50

_1

_. (b) Altitude 4,600 m

110 -. I.!!: !!!!....i!! 'li:!! ...... !i:! ::! i:: : !! !!:i :i........ ' :!!: :::" !i!".......... !i!: !i! !i!i !!i: :!::I

"r-o I00 --!-_i.-.25 __T!T. =!- ::-T- ',.=7-i_?!5:.-IT:.=.:-., "

_°......... !!i!i._,=i ,,,:.......... iii,:_i _.i_:i:1.... !ii:1!...... _!!,::I__.... !iiiLi:!i:.... !i!i t1__!i!..

12 - l!iili ! i i

i ......

_u , . .

0 200 400 600 800 1000 -

Frequency, Hz, "

v

FIGURE 27, NARROWBAND SPECTRA OF CABIN SOUND PRESSURE LEVELS AT

LOCATION 31 PORT PROPELLER, HIGH RPM; STARBOARD PROPELLER,

LOW RPM,

-64-
(a) Port Propeller Alone

.; i T

11 0 ~~--:-.-,.-:"'"--:--..-,~-:-,;-;,-:--.-.:-.-.. """l'.-••----r-....,~-r---.,.-:-~~_.,.-r__-_t ., " t, "" I, . "

(b) Starboard Propeller Alone

::: ,._-....:.j~...:-.-._~.+-.-:-2-1.--.-_-~-;:.-.-;::.'=;~-:~-,:"'_- ..--:-.,-,~.--:---~-;-::~I-:-..-_~.-:;-_.":"' .•-•.-:::-";-.:-:'.-:.-.i~I-."" .. • !'" I . .. . . : .

" , ; ..

,. ,... :!;: .'0- --. ...._.._ ...... . ; •. ; ·1 .•

. , .. ~---:

'! . ,. . :-:.~~.

•• ".", t! ,. ,,'1

: l I, i : : : :

-:-:-. '~'7i-;+-'-

.. .. . .. , ""'" .... ,. " " . .. .,.,

:::; ;- :~~ ;:;: ~~ -.:-. ..:-:-.;; -~~~;~ ~;. ~~ -~; :~:: ~-;-:~ ~-:,.

;:.. ,·1" , .. :

90 . ,

,.

.,' . , .. ,t .,

80

70

60

100

,

>

OJ

..J

OJ

11l

11l

OJ

c..

"0

c:

o

Vl

cc

"0

.

ltl

c..

I

o

u

E

o

N

OJ

80 .~-:+.

70

60

SO

0

I~ .. . -- .. - --..-

200

...

.,

400 600

Frequency, Hz.

.. ... ..."..::: .--- -T--- .,.--...-- ~- -~--- -_.

, ::': I::: ::: ,.,,,

800 1000

FIGURE 28. NARROWBAND SPECTRA OF CABIN SOUND PRESSURE LEVELS AT

LOCATION 3; SINGLE-ENGINE OPERATION.

-65-
110 "

O Port Propeller

100 _ _ _ A Starboard Propeller O

A

90 " Z_

.

_ o

o

80 A O

A O _ O

_I- A

O

_. O

o 70 -

°-- 0

E

c_ (a) Low RPM

I'N

m 60 : I I I I I i I I I

"O

I 2 3 4 5 6 7 8 9 10

-_ 110 -

>

0J

-I

¢J

A

100 - A

s,.

tmo 90 - @ A

o

_ o o

_ o

tl o

o

o

o 0

70 = g "

(b) High RPM

60 , I I I I i i I I m I

I

I 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGUI',E 29. COMPARISON OF HARMONIC SUU;JD PRESSURE LEVELS MEASURE_)

IN UNTREATED CABIN UNDER REPEATED FLIGHT CONDITIONS;

PROPELLERS AT DIFFEREI'4T Hi.iv1: MICROPHONE LOCATION 3.

-66-
110 "

O Port Propeller

100 _ _ Z_ Starboard Propeller

$

90 "

• O

O

80 " _ o

O O

m 0 n O

t A O o

L

u 70 - 0 ,_

E

c= (a) Low RPM

(u

t_

c_ 60 I I I I I I t i t I

"O I 2 3 4 5 6 7 8 9 10

110 -

> O

t_

m 0 m 100 -

O

n O

-_ A

m

°

90 -

8

O

o 6

o Z_

80 - Z_ &

A A O

& A

It _, A

o

A

o o

. 70 - & O

(b) High RPM

t

60 . I t I I I I I = J

1 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 30, COMPARISON OF HARMONIC SOUND PRESSURE LEVELS MEASURED

IN UNTREATED CABIN UNDER REPEATED FLIGHT CONDITIONS;

PROPELLERS AT DIFFERENT RPM; MICROPHONE LOCATION 6.

-67-
The data in Figures 29 and 30 show that the range of sound

pressure levels can vary from less than 1 dB to almost 13 dB,

depending on harmonic order, microphone location and test

condition. However, when averaged over harmonic orders and microphone locations the data variability is almost independent of propeller or test condition, the average range of sound pressure

levels for an individual harmonic being 3.8 dB for the port propeller and 4.8 dB for the starboard. These values are similar to

the average values for the exterior pressure field (see Section

3.2) although in that case the port propeller showed a slightly

higher average variability than did the starboard. However, the

standard deviation for the variability is higher for the interior

sound pressure levels than for the exterior (typically 3.0 dB compared to 1.5 dB) indicating that the interior sound pressure

levels have a wider scatter.

Consider now interior sound pressure levels associated with test

conditions 5 through 8 and 13 through 16 for which both propellers

were operated at the same rpm, but the relative phase between the

propellers was set at four different nominal test conditions.

Data associated with cabin microphones 3 and 6 are shown in

Figures 31 and 32. The first observation is that the harmonic

sound levels, for a given microphone and flight altitude, follow

roughly the same general trend with harmonic order irrespective of

phase setting. However, the data variability for an individual

harmonic order is quite large, the average range of sound pressure

levels for an individual harmonic being about 9.5 dB when averaged

over all harmonics and both flight altitudes. The associated

standard deviation is about 3.5 dB.

Such an evaluation, which is made without regard to relative phase

setting, gives a general appreciation of the strong role played by

propeller phase, but it is not necessarily a good way to judge

-68-
110 - Test Condition

100 V 7

n 8

90

80

70 i

(a) Altitude 4,600 m

_ 60 i I I I I i I

I 2 3 4 6 8 9 10

•_ 110

Test Condition

0 13

100 g ! ! ,b, 14

a v is E] 16

7 v

80 D

: 70 --

(b) Altitude 9,100 m

60 * I I I i i I I l I

1 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 31..COMPARISON OF HARMONIC SOUND PRESSURE LEVELS MEASURED

IN UNTREATED CABIN UNDER RE.._EATED FLIGHT CONDITIONS;

PROPELLERS AT SAME RPM; MICROPHONE LOCATION 3

-69-
110 "

Test Condition

O 5

100 _ A 6

V _' 7

A _ I_ 8

_ _ .

m A v I

u 70 - A O

"_ o

(a) Altitude 4,600 m

L

60 I I I I I I I f I I

"D

I 2 3 4 5 6 7 8 9 10

110 -

.a Test Condition

_J

O 13 I/I

_ 100 - ! A 14

V 15

m I_ 16

"O

to

m 90 - _ Z_

70 -

A .

a, (b) Altitude 9,100 ,n

60 . I I I I I I I I I

I 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 32..COMPARISON OF HARMONIC SOUND PRESSURE LEVELS MEASURED

; IN UNTREATED CABIN UNDER REPEATED FLIGHT CONDITIONS;

i PROPELLERS AT SAME RPM; MICROPHONE LOCATION 6

1 -70-

!
data repeatability. This can be performed more appropriately when

(nominal) relative phase is maintained constant. Data for microphones 2, 3 and 6 have been analyzed in this manner; the data were

. averaged over three flights for each propeller relative phase setting and then the results were averaged over the four phase

settings. Average variability for each harmonic and each microphone is plotted in Figure 33, where it is seen that, with few

exceptions, the data variability is always less for test conditions 5 through 8 (test altitude of 4600 m) than for test conditions 13 through 16 (altitude of 9100m). When averaged over the

three microphones and ten harmonics for test conditions 5 through

8, the data variability for any individual harmonic and propeller

relative phase setting is 3.7 dB. The corresponding average variability for test conditions 13 through 16 is 5.5 dB. The standard

deviation is 3.1 dB in each case.

Two comments can be made regarding the results obtained when

analyzing the data separately for each nominal relative phase setting of the propellers. First, the data variability is similar to

that observed when the propellers are operated at different rotational speeds. Secondly, the greater variability in the data for

the higher airplane altitude is consistent with the propeller

relative phase setting in Table i0, where it is seen that the

relative phase setting was less repeatable at the higher altitude

than at the lower altitude.

One factor which could affect the data variability is the resolution bandwidth used in the data reduction process. In early work

on an Aero Commander airplane with reciprocating engines, it was

" noted [15] that, since propeller blade passage tones are not perfect sine waves but in fact have finite bandwidths, it is desirable to use a resolution bandwidth that is at least as wide as the

tones being analyzed. For that particular test, a bandwidth of 2

-71-
(a) Location 2 A Altitude 9,100 m

O Altitude 4,600 m 10--

O

A A

A A O A

5-- 0

O O

A O

O O

O O

0- I I I I I I I I I I

"O

d

(b) Location 3

O

..J

o 10- A A L

I/)

A A A

o

_" A

_" O

f- s- o A o

"_ 0 0 0 A o

O A O

o O

o I I I I I I I I I I

to

c_

(c) Location 6 D_

to

o 10--

< O

O

5- A A 0 o A A

A A

O O O O O

0 I I I I I I I I I I

I 2 3 4 5 6 7 8 9 10

Harmonic Order

FIGURE 33. RANGE OF HARMONIC SOUND Pr_ESSURE LEVELS MEASURED IN

UNTREATED CABIN FOR FLIGHTS I THROUGH 3. PROPELLERS

AT SAME RPM; DATA AVERAGED OVER FOUR NOMINAL

SYNCHROPHASE SETTINGS.

:_ -72-

i

!
tO 4 Hz appeared to be a good compromise. A second item of

consideration is the speed stability of the propellers; if the

speed drifts by too large an amount, the harmonic frequency could

" drift from one spectral line (when FFT data reduction methods are

being used) to an adjoining spectral line resulting in a lower

effective spectral level following averaging over the recorded

data time sample.

In the present case, the bandwidth was dictated to some extent by

the need to distinguish between port and starboard propeller contributions when the propellers were operated at different rpm. As

a consequence, the frequency resolution was 0.5 Hz for harmonics

of order 1 through 5 (frequencies below 400 Hz) and 1.0 Hz for

harmonics 6 though i0 (frequencies between 400 and 800 Hz). The

associated half-power bandwidths for the effective filters are

approximately 0.9 and 1.7 Hz, respectively.

The possibility that filter bandwidth might be influencing the

data was explored by analyzing time histories of harmonic sound

pressure level signals obtained from the output of the SD 360

narrowband analyzer. The analysis was performed first for data

associated with test conditions where the two propellers were

operated at different rotational speeds. Data from such an analysis is shown in Figure 34 for seven harmonics. It is seen that

the sound levels for the lowest order harmonics are very stable as

a function of time, but as harmonic order increases the fluctuations in the data also increase in magnitude. However, in spite

of these fluctuations, there is no general upward or downward

trend in sound level which would be associated with a drift in

harmonic frequency into or out of the spectral band. The interpretation placed on the data in Figure 34 is that any measured

-73-
79 Hz 393 Hz

]__ _ __/_.- -_. .

I dB

_---10 secs.---_

U

C

_J

_J

_-_J 157 Hz 550 Hz

n_

.gl

t

m

_ 236 Hz 6117 Hz

.-1

o Time L/I

314 Hz

m

Ik.

Time

FIGURE 34. TIME HISTORIES OF HARMONIC SOUND PRESSURE LEVELS IN

CABIN; TWO ENGINES OPERATING AT DIFFERENT RPM (CONDITION 9)

-74-
fluctuations in sound pressure level are actual fluctuations at

the observation point and are not artifacts of the data reduction

. process and filter bandwidth.

The analysis was then repeated for data associated with test

conditions where the two propellers were operated at the same rpm.

Typical data for such conditions are shown in Figure 35. The time

histories show data irregularity patterns which are similar to

those in Figure 34, but now there are underlying trends of

increasing or decreasing sound level during the 30-second recording time. Since it has been determined, by arguments such as

those in the preceding paragraph, that the data reduction methods

are not introducing these general trends, the results in Figure 35

are interpreted as indicating the influence of slight drifts in

relative phase between the two propellers.

4.3 One-Third Octave Band Spectra

The narrowband spectra are of interest mainly because they

provide data on the harmonics of the blade passage frequency.

However, it is possible that the broadband components in the

spectra will be of interest also, for example when evaluating the

contributions from the turbulent boundary layer. Consequently,

interior sound pressure levels from flight #3 were reduced in

terms of one-third octave bands, as well as narrowband spectra.

The results of the one-third octave band analysis are given in

Appendix D for future reference; the data are not discussed in

detail in this report.

-75-
-

-~

306 Hz

383 Hl

-

-

-

-- - - -

-

-

1---1 0 secs~

77 Hz

153 Hz

-

-

:..

CD

"0

230 Hz 459 Hz

Time Time

FIGURE 35. TIME HISTORIES OF HARMONIC SOUND PRESSURE LEVELS IN

CABIN; TWO ENGINES OPERATING AT SAME RPM (CONDITION 8)

-76-
5.0 SOUND LEVELS IN TREATED CABIN

After flight #3, the interior surfaces of the cabin sidewall and

ceiling were covered with fiberglass batts, as described in

Section 2.4. There was no acoustic treatment on the cabin floor,

but a heavy, flexible bulkhead was installed between the cockpit

and the cabin. Sound pressure levels in the treated cabin were

then measured during flight #4. Unfortunately, a malfunction of

the propeller synchrophaser limited the number of test conditions

for that flight. Also, as there was only one flight in the

treated configuration, it was not possible to explore data variability for that configuration. Interior sound pressure levels

measured in the cabin during flight #4 are given in Appendices C

and F, with Appendix C containing harmonic sound pressure levels

and Appendix F one-third octave band spectra.

A general assessment of the noise reduction provided by the

fiberglass treatment can be obtained from a direct comparison of

narrowband sound pressure spectra measured in the cabin during

flights 3 (untreated) and 4 (treated). Comparisons of this type

are given in Figures 36 and 37. The difference in spectrum level

at a given frequency is a measure of the insertion loss provided

by the treatment (assuming the exterior sound field is constant).

The first observation regarding the spectra in Figures 36 and 37

is that the sound pressure levels at microphone location i, in the

cockpit, are essentially unaffected by the cabin treatment. It

should be remembered that, in the treatment interior the cockpit

- is isolated from the cabin by the flexible bulkhead. Furthermore,

comparing spectra in Figure 36, it is seen that the sound pressure

" levels in the untreated cabin are similar in value at locations 1

-77-
(a) Location I

110

-- Untreated (Flight #3)

100 .... Treated (Flight #4)

so 1

f 80

o

uJ_

E

_ 70

L

co 60 v

"O '' ',I "

"J '- V

• 50

S,. (b) Location 2

110 "

1/I

_J

•"o 100

0

1/1

90

80

70 t

I11

I|I

Il l!

60 \, ,,_,

50 I I ,.,I

0 200 400 600 800 1000

Frequency, Hz.

m

FIGURE 36, EFFECT OF FIBERGLASS TREATMENT ON CABIN NARROWBAND

SOUND PRESSURE LEVEL SPECTRA: ALTITUDE 9,100 m.

-78-
(c) Location 3

110

100 --- Untreated (Flight B)

- --- Treated (Flight #4)

50

( d) Location 4

110

100

90

.

l'O

D.

I

o

s..

u

E

c

N

CI)

s..

,

IV

>

CI)

...J

CI)

s..

CIl

CIl

CI)

s..

c..

"'0

C

o

l/l

90

80

70

60

,I

• \. I I I' !

\.. 'II II'

'I' I' h .,II' ~II ,rl'l 1_ I II

I , ", ',r i," n I ~'I '1) '10 ",>'.. IJ' II ~'~ II \,'..... !,./../1,;\, '\. ,~I Il_~ J~ Il I

• . • "."v'·':"'Il'" 'J" I!,.:' 11

1

1

",,""'.. J'. II

80

600 800 1000

Hz.

400

Frequency,

200

70

SO 1.-..:- 1..- 1..- --1__......;.;._--1.......;. ......

o

60

"

FIGURE 36. CONT li~UED

-79-
(a) Location 1

110.-1'-----------------------.......

100 Untreated (Flight #3)

Treated (FI ight #4)

co 60

"'0

50 ..... _ ___J

(b) Location 3

90

80

70

90

110,...----------------------------t

100

.

10

c..

I

o

.!::!

E

o

N

Q)

80

70

I

I

,

I I "

60 ,

I

I

SO

0 200 400

Frequency,

600

Hz.

800 1000

• FIGURE 37. EFFECT OF FIBERGLASS TREATMENT ON CABIN NARROWBAND

SOUND PRESSURE LEVEL SPECTRA: ALTITUDE LI,GOO m.

-80-
and 2, but in the treated cabin the sound levels are generally

higher at location 1 than at location 2. These observations suggest that the sound pressure levels in the cockpit are dominated

by airborne transmission through the cockpit windows and structure, or by structureborne transmission with subsequent radiation

into the cockpit. The sound pressure levels in the cockpit do not

appear to be dominated by airborne transmission via the cabin.

When acoustic spectra are compared for microphone locations in the

cabin it is found that the insertion loss provided by the fiberglass treatment increases with frequency. For a given frequency,

the insertion loss at location 2 appears to be lower than that at

either location 3 or 4. The reasons for the reduced effect at the

forward location are not readily apparent since the treatment was

applied uniformly over the cabin sidewall and roof. There are

structural differences, location 2 being close to the emergency

hatch. Also, location 2 is closest to the cockpit and thus could

be influenced by sound leaking around the flexible bulkhead. Both

of these factors could have more of an influence on the sound

levels at location 2 than at other locations in the cabin.

A more detailed evaluation of the insertion loss provided by the

treatment is presented in Section 6.3 in terms of harmonic components and one-third octave band spectra.

-81-
6.0 DISCUSSION

The main objective of this report is topresent data for possible

future analysis. To this end an attempt has been made to provide

as much detail as possible regarding the data acquisition and

reduction methods, as well as the narrowband and one-third octave

band acoustic data. However, some discussion can be provided

within the present scope of work. The discussion is directed

towards three of the more important aspects of the results--the

effect of cabin pressurization, the difference between exterior

and interior sound pressure levels, and the influence of the

fiberglass treatment on cabin sound pressure levels. It should be

emphasized that the discussion is based on only a small percentage

of the total amount of data acquired during the test program and

that, as a consequence, the conclusions should be regarded as only

tentative. It is hoped that the comments and interpretations of

the results will stimulate a more detailed analysis of the data

presented in the appendices of this report.

6.1 Cabin Pressurization

The influence of cabin pressurization on cabin sound pressure

levels was investigated during flight at a nominal altitude of

3,000 m (i0,000 ft). Measurements were made first with the cabin

unpressurized; the cabin was then pressurized to a differential of

about 26 kN/sq m (3.7 psf) and the measurements repeated.

The effect of cabin pressurization on interior sound levels can be

seen in Figure 38, the measurements being made at an airplane °

altitude of 3,000 m (i0,000 ft). While it is difficult to identify any particular trend in the sound levels at propeller harmon- °

ics, certain other characteristics can be seen in the spectra.

Some of these characteristics are identified by arrows in the

-82-
110

(a)hop =0 .,

90

100

.

ltl

0-

I

o

l..

U

E

<:)

N

(l,)

l..

co

"0

,

Qj

>

(l,)

...J

(l,)

l..

til

til

(l,)

l..

c..

"0

c::

o

(/)

(b) hop = 26 kN/ sq. m (3.7 psi)

11 0 _...::..-~--.:._--_......:._--~--~--:---:'-~-:----:----:-~..,

;' I I -1-- I -I L

1

, .. ·--rl_' -' ....1. .._-""T:-' .::: ,i.:: ::_.~ L· ': .:.. ... .. 'I~" i!

... i ..-:::: -. ': I .. ' .

1 ". -.. I,,, --",+., ,,,-'c-- ··1· .. ..... :. t·-

400 600 800 1000

Frequency, Hz.

200

. " I .•. 'I

80 .. ·:1· .. r"- .:....:._. "''1''--'- .. :.....1 .. -.~ :::. :~..:.- ..:: -~--j-

,~~.I.il. . ~-- _L '- i Li\-'TfrrJ ;~\~ : M' .:': T' .:~ I tlJ-IA. J\ I !Ir' __ IV~"" '.. I

70 '" :~·:-ilt-J:: VjV1. r+~ .. ~'-:-J"- '.. ~1'::-:·~,-:: ...b-·· ;... :::: J .'.:: .', .;.:. :'1" , :\,1 ~I~ i

I . . , 60 ~.~ .• -- .. :-- _~:~ ..--. ::-. "\ -- :.. :--j' :..

SO r.

l

.;....;. ~.':'=:=====:==:=:_-_--+..;..l-._·.~:~~~~:·_·_.:...11---:_..;....--:..--:·t..;....-...;,+ __·..;..;'_'_-1\;...--..;..11_'....... --

o

FIGURE 38. NARROWBAND SPECTRA OF CAB li-J SOUND PRESSURE LEVELS AT

LOCATION 3; EFFECT OF CABIN i-'RESSURE DIFFERENTIAL.

(AIRPLANE ALTITUDE 3,000 m)

-83-
figure. In the case of Figure 38(a) the arrow indicates a

frequency region in which the sound pressure levels decrease as

the pressure differential increases. Conversely, the arrows in

Figure 38(b) show frequency regimes where the sound pressure

levels increase with pressure differential.

There are at least two phenomena that are influencing the results.

First, increasing the pressure differential will introduce

in-plane stresses in the fuselage skin. These stresses will

increase the effective stiffness of the structure and shift some

of the resonances to higher frequencies. This could influence the

response of the structure to the exterior pressure field and the

acoustic radiation into the cabin. Secondly, for a given level of

vibration in the structure, the radiated acoustic pressures will

be proportional to the gas density in the receiving volume. In

the present case, assuming a negligible change in temperature in

the cabin, it is predicted that the sound pressure levels in the

cabin would increase by 3.3 dB when the cabin pressure is increased (and the vibration of the structure is assumed constant).

The effect of pressure differential can be studied in more detail

by considering the changes in harmonic sound pressure level or

one-third octave band level when the pressure differential is

increased. Ths is achieved by determining the difference between

the sound levels associated with conditions 1 and 4 or between

conditions 2 and 3. Data in this format are presented in Appendix

G for microphones at locations 3 and 6; the same data are plotted

in Figure 39 through 44. It should be noted that the results have

not been adjusted for changes in the measured exterior pressure

levels from condition to condition. The data in the figures refer

to flights 3 (untreated cabin) and 4 (treated cabin), the flights

being identified in the figures by the symbols F3 and F4

-84-
MIC#:3PORT . ENGINE COMPONENTS.

4O

F3 = Flight 3

F4 = Flight 4

" CI = Condition I

:30 C2 = Condition 2

• C3 = Condition 3

C4 = Condition 4

-2O

• -30 l i i J i J i t l I I

1 2 3 4 5 6 7 8 9 10

Harmonic Order

u F3,C3-C2 + F3,04-C1 o F4,C3-C2 z_ F4,C4-C1

FIGURE 39. CHANGE IN HARMONIC SOUND PRESSURE LEVEL IN CABIN DUE TO

CABIN PRESSURE DIFFERENTIAL. MICROPHONE LOCATION 3; PORT

PROPELLER COMPONENT, HIGH AND LOW RPM.

-85-
MIC#3.STARBOARD ENGINE COMPONENTS.

4O

F3 = Flight 3

F4 = Flight 4

30 CI = Condition I o

C2 = Condition 2

C3 = Condition 3

C4 = Condition 4

m

20

>

J

I0 ]J

£

3

0

r 0 lw

\

E

0 -10 £

O

-2O

-30 i i i u _ J l l l l

1 2 3 4 5 6 7 8 9 10

Harmonic Order

n F3,03-02 + F3,C4-Cl o F4,C3-C2 A F4,C4-C!

FIGURE 40. CHANGE IN HARMONIC SOUND PRESSURE LEVEL IN CABIN DUE TO

CABIN PRESSURE DIFFERENTIAL. MICROPHONE LOCATION 3;

STARBOARD PROPELLER COMPONENT, HIGH AND LOW RPM.

-86-
MIC#6.PORTENGINE COMPONENTS.

4O

F3 = Flight 3

. F4 = Flight 4

_0 CI = Condition I

C2 = Condition 2

C3 = Condition 3

C4 = Condition 4

m

20

>

j I

0_c 10 i

c 0 o_

E

.C0 -10

U

-2O

-30 i i i l n I I i i l

°

I 2 3 4 5 6 7 8 9 10

Harmonic Order

13 F3,C3-C2 + F3,C4-Cl _ F4,C3-C2 A F4,C4-C!

FIGURE 41, CHANGE IN HARMONIC SOUND PRESSURE LEVEL IN CABIN DUE TO

CABIN PRESSURE DIFFERENTIAL, MICROPIIONE LOCATION 6; PORT

PROPELLER COMPONENT, HIGH AND LOW RPM,

-87-
MIC#6.STARBOARD ENGINE COMPONENTS.

4O

F3 = Flight 3

F4 = Flight 4

30 C 1 = Condition 1 .

C2 = Condition 2

C3 = Condition 3

C4 = Condition 4

m

20

>

_J

10 ]]

[

3

0

c 0

'- \

c \

o -10 £

u

-2O

-50 i i i I i l I I I I I

1 2 3 4 5 6 7 8 9 10

Harmonic Order

n F3,03-02 + F3,C4-Cl o F4,C3-C2 A F4,04-01

FIGURE 42. CHANGE IN HARMONIC SOUND PRESSURE LEVEL IN CABIN DUE TO

CABIN PRESSURE DIFFERENTIAL, MICROPHONE LOCATION 6;

STARBOARD PROPELLER COMPONENT, HIGH AND LOW RPM.

-88-
CABINMIC#3.PRESSURIZATION EFFECT.

40 F3 = Flight 3

F4 = Flight 4

C; = Condition I

C2 = Condition 2

"- C3 = Condition 3

50 C4 = Condition 4

. -30 t i ! _ 1 i i i i i i i _ I J I I I I I I J t

52 65 125 250 500 1000 2000 4000

P

I/5 0ctoveBondCenterFrequency, Hz

u F5,C3-C2 + F5,C4-C1 o F4,05--02 A F4,04-Ct

FIGURE 43. CHANGE IN ONE-THIRD OCTAVE BAND SOUND PRESSURE LEVEL IN

CABIN DUE TO CHANGE IN CABIN PRESSURE DIFFERENTIAL;

MICROPHONE LOCATION 3.

-89-
CABINMIC#6. PRESSURIZATION EFFECT.

40

F3 = Flight 3

F4 = Flight 4

Cl = Condition 1

C2 = Condition 2

C3 = Condition 3

50 " C4 = Condition 4

--50 I I I I I I I I 1 I I I I i I 1 I 1 I I I i

32 63 125 250 500 1000 2000 4000

q

1,/30ctoveBendCenterFrequency, Hz

u F5,C5-C2 + F5,C4-C1 o F4,C5-C2 A F4,C4-C1

FIGURE 44, CHANGE IN ONE-THIRD OCTAVE BAND SOUND PRESSURE LEVEL IN

CABIN DUE TO CHANGE IN CABIN PRESSURE DIFFERENTIAL;

MICROPHONE LOCATION 6.

-90-
respectively. Conditions 1 through 4 are identified in the figure

legends by symbols C1 through C4.

" Considering first the data for the harmonics, Figures 39 through

42 show quite a large amount of data scatter. It should be remem-

" bered with respect to these figures that the data are plotted in

terms of harmonic order rather than frequency; a given harmonic

for test conditions 1 and 4 occurs at a different frequency than

is the case for conditions 2 and 3. Furthermore, the data in the

figures refer to both untreated and treated interiors. Finally,

the data represent only a small fraction of the total data recorded and listed in Appendices B and C. The intent here is to show

general trends rather than perform a detailed analysis. These

trends show that, as cabin pressure differential increases, the

cabin sound level for the first propeller harmonic increases by a

small amount (on the average, less than 5 dB). The sound levels

for the second and third harmonics decrease by a small amount, and

sound levels for the fourth harmonic increase slightly. The largest increases in sound level occur for the fifth and sixth harmonics, where changes as high as 29 dB are observed and the average

increase is 5 to 13 dB (where the averaging is performed over all

test conditions and both flights for a given propeller and

microphone).

Turning to the one-third octave band spectra shown in Figures 43

and 44, it is seen that there are alternating frequency ranges of

increasing and decreasing sound pressure level. However, in very

few frequency bands does the sound level increase exceed the 3.3

• dB value predicted on the basis of the change of air density in

the cabin. The exceptions are essentially the one-third octave

bands centered at 315, 400 and 500 Hz. These are the frequency

bands containing the fourth, fifth and sixth harmonics of the

propeller blade passage frequency. This means that, if the effect

-91-
of cabin air density is removed from the data, the increased

stresses in the structure due to cabin pressure differential have

the effect of reducing noise levels in the cabin at most

frequencies.

6.2 Sidewall Noise Reduction

By definition, the noise reduction provided by the fuselage

structure and cabin treatment is the difference between the exterior and interior sound pressure levels. This quantity can be

measured fairly readily when the exterior and interior sound pressure levels are spatially uniform. However, such a condition is

not satisfied in the present environment; the situation is further

complicated by the presence of only one exterior microphone on

each side of the fuselage. As a consequence, the term "noise

reduction" is used here in the loose sense of the difference

between sound pressure levels measured at a single exterior microphone and a single interior microphone. Furthermore, in the

present analysis the interior microphones are restricted to locations 3 and 6, and the data are restricted to flights 3 and 4.

Noise reductions measured in the untreated cabin at harmonics of

the propeller blade passage frequency are listed in Appendix H;

corresponding data for the treated cabin are given in Appendix I.

Selected data, representative of the different flight test conditions, are shown in Figures 45 through 48. The results for the

two microphone locations tend to be different in character. At

location 6 the noise reduction in the untreated cabin first

increases with harmonic order (or frequency) and then is essentially independent of harmonic order at higher orders. In the

treated cabin the noise reduction increases markedly as harmonic "

order increases. In contrast, at microphone location 3 the data

--O0_
FLIGHT#3:EXTPORTSPL- MIC6SPL

7O

. 60

5O

0]

-0

i.

E

o 40

o

3

U

3O

oo

z

2O

10

_" 0 J J _ J J i J J i J

1 2 5 4 5 6 7 8 9 10

Hermonic Order

u Condl + Cond4 o Cond9 A Cond17

FIGURE 45. HARMONIC NOISE REDUCTION FOR UNTREATED CABIN: FLIGHT 3,

EXTERIOR PORT MICROPHONE, INTERIOR MICROPHONE LOCATION 6.

-93-
FLIGHT #3:EXTSTBDSPL-MIC3SPL

70

60

50

rn

'O

E

o 40

:p

V

3

-0

n, 30

I/1

GO

Z

2O

10

0 I 1 I 1 I I 1 ,1 I I ,,

1 2 3 4 5 6 7 8 9 10

,if.

Harmonic Order

n Condl + Cond4 o Cond9 A Cond17

FIGURE 46. HARMONIC NOISE REDUCTION FOR UNTREATED CABIN: FLIGHT 3,

EXTERIOR STARBOARD MICROPHONE, INTERIOR MICROPHONE

LOCATION 3.

-94-
FLIGHT #4:EXTPORTSPL- MIC6SPL

70

. 60 '_

._m-o4., oc" 0 50. 4 /_

0

n, 3o

.__

0

Z

2O

10

Ol I l I I l I ! l l l

1 2 3 4 5 6 7 8 9 10

i,

Harmonic Order

n Condl + Cond4 o Cond9 A Cond17

FIGURE 47, HARMONIC NOISE REDUCTION FOR TREATEDCABIN: FLIGHT 4,

EXTERIOR PORT MICROPHONE, INTERIOR MICROPHONE LOCATION 6.

-95-
FLIGH#4:TEXTSTBDSPL- MIC3SPL

70

t

60

50

m

O

ro_o 40

4J

U

3

30

o_

0

Z

2O

I0

0 I I I I I I I I I I

1 2 3 4 5 6 7 8 9 10

ill

Harmonic Order

u Condl + Cond4 o Cond9 A Cond17

FIGURE 48, HARMONIC NOISE REDUCTION FOR TREATED CABIN: FLIGHT 4,

EXTERIOR STARBOARD MICROPHONE, INTERIOR MICROPHONE

LOCATION 3.

-90-
show more scatter and appear to be independent of harmonic order

in the untreated cabin. Even when the cabin is treated with

fiberglass there is only a weak increase of noise reduction as

: harmonic order increases.

Associated one-third octave band noise reduction spectra are given

in Appendices H and I, and Figures 49 through 52. Interpretation

of these spectra has to be performed with caution since the noise

reduction is a function of the transmission loss provided by the

sidewall, the absorption in the cabin, the dominant excitation at

a particular frequency and the dominant transmission path. As an

example consider the low frequency range below i00 Hz. The onethird octave band noise reduction spectra show low noise reduction

in the 25 Hz band, high noise reduction in the 40 Hz (and sometimes the 50 Hz) band and relatively low noise reductions in the

50 to 80 Hz bands. Inspection of the corresponding narrowband

spectra for the exterior and interior sound pressures shows that

the interior sound field contains a strong discrete component at

the blade passage frequency of about 77 Hz and fairly strong components at the propeller shaft rotational frequency of about 26 Hz

(and sometimes at its second harmonic of about 52 Hz). In contrast the exterior pressure field contains only the 77 Hz component at the blade passge frequency. It is possible that the propeller shaft component is structureborne and, thus, in this type

of analysis the "noise reduction" will be artificially low. At

frequencies between the discrete components the exterior pressure

field is probably dominated by the turbulent boundary layer on the

fuselage. Typically, at low frequencies this excitation is not

very efficient at exciting the structure; the corresponding noise

" reduction will thus be high--as is shown in the 40 Hz band.

Finally, the propeller blade passage component lies in the 80 Hz

band and the dominant transmission path may well be airborne

-97-
FLIGHT#5.EXTPORT- MIC#6

7O

60

a

0

52 65 125 250 500 1000 2000 4000

1/50c[ave BandCenLerFrequencyHz,

E] Cond! + Cond4 o Cond9 A Cond17

FIGURE 49. ONE-THIRD OCTAVE BAND NOISE REDUCTION FOR UNTREATED

CABIN: FLIGHT 3, EXTERIOR PORT MICROPHONE, INTERIOR

MICROPHONE LOCATION 6.
FLIGHT#3.EXTSTARBOARD - MIC#3

7O

6O

10

0 I I I I I 1 1 I I I I I I I I I I I I I 1 I

32 63 125 250 500 1000 2000 4000

It,

1/50c[ave BandCenf.erFrequency, Hz

n Cond! + Cond4 o Cond9 A Cond17

FIGURE 50, ONE-THIRD OCTAVE BAND NOISE REDUCTION FOR UNTREATED

CABIN: FLIGHT 3, EXTERIOR STARBOARD MICROPHONE,

INTERIOR MICROPHONE LOCATION 3,

-99-
FLIGHT#4. EXTPORT-MIC#6

70

60

10 /

/

0 I 1 I I I I I I I I I I I I 1 I I 1 1 I I I -

,32 6,3 125 250 500 1000 2000 4000

ii

1,/3OctaveBondCenterFrequency, Hz

u Cond! + Cond4 o Cond9 A Cond17

FIGURE 51. ONE-THIRD OCTAVE BAND NOISE REDUCTION FOR TREATED

CABIN: FLIGHT 4, EXTERIOR PORT MICROPIIONE, INTERIOR

MICROPHONE LOCATION 6.

-100-
FLIGHT#4.EXTSTARBOARD - MIC#5

70

6O

J

10 ,:

/

I/

0 1/I I I I I t I I I I I I I I 1 I I I ! I I I

32 6:5 125 250 500 1000 2000 4000

Ii

1/3 OctaveBQndCenterFrequency, Hz

n Cond1 + Cond4 <> Cond9 A Cond!7

FIGURE 52. ONE-THIRD OCTAVE BAND NOISE REDUCTION FOR TREATED

CABIN: FLIGHT 4, EXTERIOR STARBOARD MICROPHONE,

INTERIOR MICROPHONE LOCATION 3.

-i01-
through the sidewall. Thus, the usual noise reduction interpretation is valid in this frequency band, with the understanding that

the actual value measured will be dependent on the particular

choice of location for the exterior microphone.

At frequencies above about 630 Hz for the untreated cabin the main

noise source is the exterior turbulent boundary layer, and the

noise reduction increases in value as frequency increases, at a

rate somewhat greater than 6 dB for a doubling of frequency. _en

the fiberglass treatment is introduced this high frequency regime

begins at a much lower frequency--about 160 Hz. This is to be

expected because the fiberglass increases both the transmission

loss through the sidewall and the absorption in the cabin, particularly at higher frequencies.

The data in Figures 49 through 52, and in Appendices H and I show

that for the untreated cabin the noise reduction lies in the range

20 to 30 dB for much of the frequency range of interest. When the

fiberglass treatment is installed the noise reduction is greater

than 30 dB for most frequencies shown.

6.3 Insertion Loss

The insertion loss provided by the fiberglass treatment is

represented by the change in sound pressure levels measured in the

treated and untreated cabin. Values of the insertion loss can be

obtained, for example, by comparing sound pressure levels measured

in the cabin before (flight 3) and after (flight 4) installation

of the treatment. Simple spectral comparisons of this type are

made in Figures 36 and 37, and discussed in Section 5. The discussion will now be taken a step further by considering first the

changes in harmonic sound pressure level and then the changes in

one-third octave band sound pressure level.

-102-
Insertion losses measured at harmonics of the blade passage

frequency are listed in Appendix J for microphone locations 3 and

• 6, and plotted in Figures 53 through 56.• The insertion losses

were obtained simply by calculating the difference in cabin sound

" pressure level between flights 3 (untreated cabin) and flight 4

(treated cabin). Consequently, no account was taken of any possible change in exterior sound pressure level.

The data in Figures 53 through 56 show some general trends of

increasing insertion loss with increasing frequency. There is,

however, quite a large amount of scatter in the data. This is not

surprising since the insertion loss represents the difference

between two measured sound pressure levels which themselves have

significant data variability, as has been discussed in earlier

sections of this report. The data presented in the four figures

represent examples from four nominal flight conditions--zero

pressure differential (condition i) and full pressure differential

(condition 4) at an altitude of 3,000 m, and full pressure differential at altitudes of 4,600 m (condition 9) and 9,100 m

(condition 17). However, it is difficult to determine any particular influence of flight condition on the measured insertion loss

values shown in Figures 53 through 56.

It was thought possible that part of the scatter in the data could

be attributed to variations in the exterior sound pressure levels

from flight 3 to flight 4. Thus, the measured insertion loss was

recalculated by taking the differences between the measured noise

reductions for flights 3 and 4. In this manner, any changes in

• exterior sound pressure level were taken into account. Resulting

insertion loss values are tabulated in Appendix K and plotted in

Figures 57 and 58.

-103-
FLT#3-#4:MIC3,PORTENGINE COMP.

40

30 -.

2O

rn

0

0

F

0

_ 0 JA/ a

I

L

-10 ._

-20

-30 l l l i I x i l l l

I 2 3 4 5 6 7 8 9 10 p

Hermonic Order

n Condl + Cond4 o Cond9 A Cond17

FIGURE 53, HARMONIC INSERTION LOSS PROVIDED BY FIBERGLASS TREATMENT:

PORT PROPELLER COMPONENT, INTERIOR MICROPHONE 3. (NO

ADJUSTMENT FOR CHANGE IN EXTERIOR SOUND PRESSURE LEVEL)

-104-
I

FLT#3-#4:MIC3,STBDENGINE COMP.

40

o

o 30

2O

in

0

10

0

.J

E

0

:_ 0

L

E

-10

-2O

. -30 l t n l i l i l i l

I 2 3 4 5 6 7 8 9 10

Hermonic Order

n Condl + Cond4 o Cond9 A Cond17

FIGURE 54. HARMONIC INSERTION LOSS PROVIDED BY FIBERGLASS TREATMENT:

STARBOARD PROPELLER COMPONENT, INTERIOR MICROPHONE 3.

(NO ADJUSTMENT FOR CHANGE IN EXTERIOR SOUND PRESSURE LEVEL)

-I05-
FLT#5-#4:MIC6,PORTENGINE COMP.

4O

.30

20

m

U

10

0

J

E

0

-10

-20

-30 l l I l l I I I I l I

1 2 ,.3 4 5 6 7 8 9 10

Hermonic Order

[] Condl + Cond4 _ Cond9 A Cond17

FIGURE 55. HARMONIC INSERTION LOSS PROVIDED BY FIBERGLASS TREATMENT:

PORT PROPELLER COMPONENT, INTERIOR MICROPHONE 6, (NO

ADJUSTMENT FOR CHANGE IN EXTERIOR SOUND PRESSURE LEVEL)

-I06-
FLT#3-#4:MIC6,STBDENGINE COMP. 4O

• 30

2O

rn

.g

10

0

J

E

0

0

L

c \

-10

-2O

.i -30 l l i i i 1 l i J I

1 2 3 4 5 6 7 8 9 10

HQrmonicOrder

n Condl + Cond4 o Cond9 A Cond17

FIGURE 56. HARMONIC INSERTION LOSS PROVIDED BY FIBERGLASS TREATMENT:

STARBOARD PROPELLER COMPONENT, INTERIOR MICROPHONE 6.

(NO ADJUSTMENT FOR CHANGE IN EXTERIOR SOUND PRESSURE LEVEL}

-107-
FLT#3-#4:MIC3,STBDENGINE COMP. 4O

30

O

m 10

Jo

E

o

L

@

r

-10

-2O

-30 i J J j I J l I J i

1 2 3 4 5 6 7 8 9 10

Harmonic Order

rl Condl + Cond4 o Cond9 _ Cond17

FIGURE 57. HARMONIC INSERTION LOSS PROVIDED BY FIBERGLASS TREATMENT:

STARBOARD PROPELLER COMPONENT, INTERIOR MICROPHONE 3.

(ADJUSTED FOR CHANGE IN EXTERIOR SOUND PRESSURE LEVEL)

-I08-
FLT#5-#4:MIC6,PORTENGINE COMP.

40

• 3O

20

m

0

10

0

J

E

0

0

y gl

-10

-2O

" -30 l I J J l i I i l l

• I 2 3 4 5 6 7 8 9 10

HarmonicOrder

n Condl + Cond4 o Cond9 z_ Cond17

FIGURE 58, HARMONIC INSERTION LOSS PROVIDED BY FIBERGLASS TREATMENT:

PORT PROPELLER COMPONENT, INTERIOR MICROPHONE 6.

(ADJUSTED FOR CHANGE IN EXTERIOR SOUND PRESSURE LEVEL)

-109-
Comparison of Figures 54 and 57 or Figures 55 and 58 shows that

the inclusion of changes in exterior sound pressure levels has

only a negligible effect on the variabiiity of the measured insertion loss. Thus the variability must be caused by other, as yet

unidentified, factors. A more extensive analysis of all the test

data might provide a better understanding of the insertion loss

and the reasons for the data variability.

Examples of insertion loss spectra measured in one-third octave

frequency bands are given in Figures 59 and 60. A more complete

tabular presentation is given in Appendix J. The spectra for the

two microphone locations show some similarities at high frequencies and some differences at low frequencies.

At low frequencies, the spectra for location 3 exhibit a fairly

smooth increase in insertion loss as frequency increases. In contrast the corresponding data for microphone location 6 show relatively high insertion losses at some frequencies and low insertion

losses at other frequencies. The results are quite repeatable for

the wide range of test conditions considered. The high insertion

losses measured at location 6 occur at frequencies close to the

propeller shaft rotational frequency and the propeller blade

passage frequency.

At frequencies above about 250 Hz, the measured insertion losses

are similar for the two locations and have maximum values of 15 to

20 dB in the frequency range 630-1600 Hz. At higher frequencies,

the measured insertion loss appears to decrease as frequency

increases. However, it is believed that this phenomenon was

caused by the limited dynamic range of the tape recorder. This v

m

limitation affected the recording of high frequency sound pressure

levels in the treated cabin.

-ll0-
.

.

FLIGHT #3 - FLIGHT #4. MIC #3

40 -r------------------------,

30 -+-------------------------1

20

rn

1J

.

Ul

Ul 10

0

.J

[

0

.-

+J 0

L

(1)

Ul

[

-10

-20 Insertion Loss Estimated on the Basis of Increased Absorption Only

- - - - ()(. =0.1 assumed for bare structure

----- =0.05 assumed for bare structure

32 63 125 250 500 1000 2000 4000

o Cond 1

1/3 Octave Band Center Frequency, Hz

+ Cond 4 <) Cond 9 11 Cond 17

FIGURE 59_ ONE-THIRD OCTAVE BAND INSERTION LOSS PROVIDED BY FIBERGLASS

TREATMENT: INTERIOR MICROPHONE LOCATION 3.(NO ADJUSTMENT

rOR CHANGE IN EXTERIOR SOUND PRESSURE LEVEL)

-111-
FLIGHT#,3- FLIGHT#4. MIC#6

40

30

2O

Insertion Loss Estimated on the Basis of Increased Absorption Only -20

= 0. I assumed for bare structure

..... _ = 0,05 assumed for bare structure

-30 I l t [ l i i _ i _ [ L i I i i _ i i I i t

32 63 125 250 500 1000 2000 4000

I/3 OctaveBandCenterFrequency,Hz

Cond! + Cond4 _ Cond9 A C0nd17

FIGURE 60. ONE-THIRD OCTAVE BAND INSERTION LOSS PROVIDED BY FIBERGLASS

TREATMENT: INTERIOR MICROPHONE LOCATION 6. (NO ADJUSTMENT

FOR CHANGE IN EXTERIOR SOUND PRESSURE LEVEL)

-112-
The one-third octave band spectra in Figures 59 and 60 show

negative insertion losses in some low frequency bands. This means

that the measured sound pressure levels were higher in the treated

cabin than in the untreated cabin. Similar results were observed

for the harmonic sound pressure levels. Data from earlier tests

[9] show similar trends, but the occurrence of negative insertion

losses in one-third octave band spectra was essentially eliminated

when discrete frequency harmonic components were artificially

removed from the computation.

The insertion loss provided by the fiberglass treatment is

influenced by transmission loss and absorption characteristics.

An estimate of the effect of acoustic absorption can be obtained

using available manufacturers data and approximations. The data

used in the analysis are shown in Table ii. In addition, values

of 0.05 and 0.i were assumed for the absorption coefficient of the

bare structure (skin and windows). Estimated insertion losses,

associated with only the changes in acoustic absorption in the

cabin, are shown in Figures 59 and 60. The predictions are

generally consistent with the measured data.

TABLE II

ASSUMED ACOUSTIC ABSORPTION PROPERTIES

Frequency (Hz) 125 250 500 i000 2000 400(

Absorption Coefficients

Sidewall Treatment 0.19 0.70 0.99 1.0 1.0 1.0

: Cockpit Curtain 0.20 0.50 0.70 0.90 1.0 1.0

Absorption for Seat with Occupant

Sabins (m 2) 0.31 0.33 0.41 0.45 0.42 0.41

(ft 2) 3.3 3.6 4.4 4.8 4.5 4.4

-113-
7.0 CONCLUSIONS

The flight test measurements provided information on exterior and

interior sound pressure levels which will be of value to future

in-flight evaluations of cabin acoustic treatments for propellerdriven aircraft. The results are summarized in these

conclusions.

7.1 Data Variability

One of the important results of this flight test program is that,

for the first time, it is possible to establish the repeatability

of measured propeller sound pressure levels at harmonics of the

blade passage frequency. The extent to which the data are repeatable is a critical factor in the in-flight evaluation of noise

control treatments installed in an airplane cabin. It was found

in the present test program that there was some variability in the

measurements; a general estimate of this variability was obtained

by taking the range of sound pressure levels (i.e., the difference, in decibels, between maximum and minimum measured values)

for each harmonic under each test condition. The data ranges were

then averaged over all harmonics and over all three flight altitudes for each of the two propeller nominal rotational speeds.

In the case of the exterior sound pressure levels, the average

range of sound pressure levels for an identical harmonic was 3 to

5 dB, depending on propeller rpm, with the greatest observed variation being about 8 dB at higher order harmonics. The standard

deviation for the range of harmonic sound pressure levels relative

to the mean was about 1.5 dB. Somewhat greater variability was

observed in the interior sound pressure levels. If the propellers

were operated at different rotational speeds, or at the same

-114-
rotational speed and the same nominal relative phase angle, the

average range of sound pressure levels for an individual harmonic

was 4 to 6 dB. The associated standard deviation for the range of

harmonic sound pressure levels about the mean was 3 to 4 dB. When

• relative phase angle was not controlled the average range of harmonic sound pressure levels in the cabin was about i0 dB. It

should be noted, however, that the new generation of synchrophasers provide much closer control of relative phase between the two

propellers than was achieved on the test airplane; the associated

variability in harmonic sound pressure levels should then be

reduced.

Implicit in this evaluation of data repeatability is the choice of

effective filter bandwidth used in the data reduction process.

The bandwidth should be narrow enough to exclude unwanted signals,

but wide enough to accept all the acoustic energy associated with

the harmonic. The data from the present tests indicated that the

propeller rpm was very stable during the data record sample, so

that filter bandwidths of 0.5 to 1.0 Hz could be used.

7.2 Exterior Sound Pressure Levels

Measurements of the sound field on the exterior of the fuselage

showed that the harmonic sound pressure levels for the propeller

adjacent to the microphone were 15 to 20 dB higher than the corresponding values generated by the propeller on the opposite side

of the fuselage. Sound pressure levels generated by the port propeller and measured on the port side of the fuselage were typically 2 to 3 dB higher than those on the starboard side generated by

the starboard propeller. Viewed from the rear, the propellers

rotate in a counter-clockwise direction and the microphones were

about 5 cm (2 inches) below the center of the propeller shaft.

Thus, it might be said that the port propeller was approaching the

port microphone and the starboard propeller leaving the starboard

-115-
microphone. However, the difference between port and starboard

sides appear to be extremely small.

The measured propeller overall sound presure levels were 7 to i0

dB lower than values predicted using two simple empirical models.

Harmonic levels, expressed relative to the associated overall

sound pressure levels, lie between the values predictd by the two

simple models.

Broadband sound pressure levels measured on the exterior of the

fuselage can be predicted, approximately, using an empirical model

for the pressure fluctuations beneath an attached turbulent boundary layer in a zero pressure gradient.

7.3 Interior Sound Pressure Levels

Cabin sound pressure levels were found to increase at some

frequencies and decrease at others when cabin pressure differential was increased. However, only in very few frequency bands did

the increase exceed the value predicted on the basis of the air

density change in the cabin. Thus, it is concluded that increased

pressure differential generally would reduce the acoustic radiation from the structure, if the air density in the cabin remained

constant.

Noise reductions provided by the untreated cabin were in the range

of 20 to 40 dB when the exterior and interior sound pressure

levels were measured at locations which were close to the plane of

rotation of the propeller. Introduction of an acoustic treatment "

consisting of 5 cm (2 inches) of fiberglass on the walls and ceiling of the cabin plus a foam and leaded-vinyl barrier between the

cabin and the cockpit increased the noise reduction in the cabin

at frequencies above about 200 Hz, but there was an apparent

decrease in the noise reduction in some lower frequency bands;

-116-
similar effects have been observed in previous test results. Part

of the increase in high frequency noise reduction can be attribu-

: ted to an increase in the acoustic absorption in the cabin. There

was no observable change in the sound pressure levels in the

" cockpit.

7.4 General Comments

Flanking paths play an important role in the experimental

evaluation of noise control treatments. On the basis of the

present study, it is concluded that an acoustic barrier should be

provided between the cockpit and the cabin to eliminate that

flanking path. Other tests are necessary to determine the roles

played by windows, floor, structureborne noise and other factors.

It is probable that these factors will be critical when evaluating

noise control treatments which provide high noise reductions.

-117-
REFERENCES

i. Vaicaitis, R., Mixson, J.S., "Theoretical Design of Acoustic

Treatment for Cabin Noise Control of a Light Aircraft", AIAA

Paper 84-2328, October 1984.

2. Vaicaitis, R., Slazak, M., "Design of Sidewall Treatment for

Cabin Noise Control of a Twin Engine Turboprop Aircraft", NASA

Contractor Report 172245, December 1983.

3. Vaicaitis, R., "Study of Noise Transmission Through Double

Wall Aircraft Windows", NASA Contractor Report 172182, October

1983.

4. Vaicaitis, R., Slazak, N., "Cabin Noise Control for Twin

Engine General Aviation Aircraft", NASA Contractor Report

165833, February 1982.

5. Vaicaitis, R., Chang, M.T., Slazak, M., "Noise Transmission

and Attenuation for Business Aircraft", SAE Paper 810561,

April 1981.

6. Vaicaitis, R., "Noise Transmission into a Light Aircraft", J.

Aircraft, 17, 2, 81-86, February 1981.

7. Vaicaitis, R., Slazak, M., "Noise Transmission through Stiffened Panels", J. Sound and Vibration, 70, 3, 413-426,

1980.

8. Grosveld, F.W., Mixson, J.S., "Noise Transmission through an

Acoustically-Stiffened Aircraft Sidewall", AIAA Paper 84-2329,

October 1984.

9. Mixson, J.S., O'Neal, R.L., Grosveld, F.W., "Investigation of

Fuselage Acoustic Treatment for a Twin-Engine Turboprop Aircraft in Flight and Laboratory Tests", NASA Technical Memorandum 85722, January 1984.

i0. Grosveld, F.W., "Noise Transmission through Sidewall Treatments Applicable to Twin-Engine Turboprop Aircraft", AIAA

Paper 83-0695, April 1983.

ii. Vaicaitis, R., Bofilios, D.A., Eisler, R., "Experimental Study

of Noise Transmission into a General Aviation Aircraft", NASA

Contractor Report 172357, June 1984.

12. Barton, C.K., Mixson, J.S., "Noise Transmission and Control

for a Light Twin-Engine Aircraft", J.Aircraft, 18, 7,

570-575, July 1981.

-i18-
REFERENCES

13. MIxson, J.S., Barton, C.K., Vaicaitis, R., "Investigation of

Interior Noise in a Twin-Engine Light Aircraft", J.Aircraft,

15, 4, 227-233, April 1978.

• 14. Roussos, L.A., Mixson, J.S., "Acceleration Response of

Fuselage Sidewall Panels on a Twin-Engine, Light Aircraft",

Proceedings, Noise-Con 81, 291-294, 1981.

15. Piersol, A.G., Wilby, E.G., Wilby, J.F., "Evaluation of Aero

Commander Propeller Acoustics Data: Static Operations", NASA

Contractor Report 158919, May 1978.

16. Piersol, A.G., Wilby, E.G., Wilby, J.F., "Evaluation of Aero

Commander Propeller Acoustic Data: Taxi Operations", NASA

Contractor Report 159124, July 1979.

17. Piersol, A.G., Wilby, E.G., Wilby, J.F., "Evaluation of Aero

Commander Sidewall Vibration and Interior Acoustic Data:

Static Operations", NASA Contractor Report 159290, October

1980.

18. Barton, C.K., Mixson, J.S., "Characteristics of Propeller

Noise on an Aircraft Fuselage", J.Aircraft, 18, 3,

200-205, March 1981.

19. Wilby, J.F., O'Neal, R.L., Mixson, J.S., "Flight Investigation

of Cabin Noise Control Treatment for a Light Turboprop

Aircraft", SAE Paper 850876, 1985 SAE General Aviation

Aircraft Meeting and Exposition, Wichita, KA, April 1985.

20. Olcott, J.W., Larson, G.C., Aarons, R.N., "B/CA Analysis:

Gulfstream i000", (see photograph, p. 50) Business and

Commercial Aviation, 49, 2, pp. 49-52, August 1981.

21. Anon., "Prediction Procedure for Near-Field and Far-Field

Propeller Noise", SAE Aerospace Information Report AIR-1407,

May 1977.

22. Ungar, E.E., et al., "A Guide for Estimation of Aeroacoustic

Loads on Flight Vehicle Surfaces", AFFDL-TR-76-91, Vol. I,

• February 1977.

23. Bhat, W.V., "Flight Test Measurement of Exterior Turbulent

• Boundary Layer Pressure Fluctuations on Boeing Model 737

Airplane", J.Sound and Vibration, 14, 4, 433-457, 1971.

-119-
-120-
APPENDIX A

Exterior Fluctuating Pressure Levels at Harmonics of Propeller

Blade Passage Frequency: Flights 1 through 4.

Notes (i) Sound pressure levels measured on the port side refer

to the port propeller, and on the starboard side to the

starboard propeller.

(2) Adjustments for broadband contributions were made on an

energy basis, with the broadband pressure level

estimated from the measured levels on either side of

the harmonic peak.

-121-
TAB LE A. 1

EXTERIORFLUSH-MOUNTEMICROPHONE D : PORT51DE

Test :Flight: RPM : BPF _ HarmoniLcevel,dBre20microPa

Conditio:nNumber: : Hz : I 2 3 4 5 6 7 B 9 10 :

I : I 15B0.079.0

2 1572.578.6 132.8 132.2 129.5 124.9 121.2 118.0 113.8 111.2 107.9 103.3*

3 1572.57B.& 130.0 129.4 127.0 122.5 118.1 I15.1 I11.0 I07.0 102.7* 98.6*

4 1575.078.8 134.3 133.5 131.1 127.1 122.B 119.2 115.5 113.0 108.6 105.5

IAverage 132.7 132.0 129.5 125.2 121.1 117.7 113.8 111.0 107.1 103.3

2 i I 1525.076.3

; 2 1525.076.3 132.2 131.1 127.8 123.B 119.0 115.3 111.6 108.4 104.0* 97.5*

3 1525.07&.3 130.0 128.5 125.2 121.0 115.9 112.1 IOB.2 104.2* 99.4* 96.1*

4 1525.076.3 134.6 133.2 130.1 125.5 120.0 117.7 114.1 I09.B 105.5* 100.0*

:Average 132.7 131.3 12B.I 123.8 118.6 115.6 111.9 I08.0 103.6 98.2

3 : l 1527.576.4

2 1525.076.3 131.7 130.0 127.0 122.2 117.0 114.0 110.5 107.3 102.4* 96.6*

3 1525.076.3 129.0 127.0 123.6 119.2 113.9 110.0 106.3 103.5 98.I * 93.0*

4 1527.5 76.4 132.9 131.9 128.4 123.5 11B.I 115.3 112.0 IOB.I 103.4* 98.7*

:Average 131.5 130.1 126.B 122.0 116.7 113.6 110.2 lO&.7 I01.B 96.7

4 I 1572.5 7B.6

2 1572.5 7B.6 131.0 130.3 127.4 122.7 119.0 115.9 111.3 108.1 103.6,101.1*

3 1572.5 78.6 129.3 129.0 125.6 120.7 117.1 113.B 110.0 107.0 101.2* 99.3*

4 IJL.5 78.6 132.9 132.2 129.5 124.3 120.6 117.6 113.9 110.8 107.0 103.4*

Average 131.3 130.7 127.8 122.B 119.1 116.0 111.7 108.9 104.6 101.6

5 I 1532.5 76.6

2 1530.0 76.5 131.0 129.5 125.3 122.7 118.7 116.0 112.5 109.9 105.0 I00.0*

3 1530.0 76.5 12B.9 127.B 123.1 119.4 115.2 111.6 IOB.7 105.2 101.7 95.7*

4

:Average 130.1 128.7 124.3 121.4 117.3 114.3 111.0 I08.2 103.7 98.4

6 : I 1530.0 76.5

2 1532.5 76.6 130.3 131.2 127.5 122.6 119.8 114.3 112.3 108.9 I04.B 99.9*

3 1532.576.6 128.2 129.1 124.7 120.1 116.7 111.7 110.0 105.4 100.8* 96.5*

4

:Average 129.4 130.3 126.3 121.5 118.5 113.2 111.3 107.5 103.2 9B.5

7 I I 1530.0129.0 129.0 128.1 124.3 121.3 115.2 112.7 109.6 107.4 101.6* 98.0* t

2 1530.0 76.5 131.1 129.9 127.5 123.3 119.3 115.5 114.0 110.2 105.9 101.2* •

3 1530.076.5 128.B 127.3 123.8 120.5 115.9 112.1 109.2 I06.B 101.5, 97.6,

i 4

:Average 129.B 12B.6 125.5 121.9 117.2 113.7 111.5 IOB.4 103.5 99.3

• adjusted_orBroadbandContributions NA NotAvailable

-122-
TABLE A.I (CONTINUED)

EXTERIORFLUSH-MOUNTED MICROPHONE: PORTSIDE

Test : FlightI RPM I BPF I HarmonicLevel,dBre20microPa

Condition: Number: l Hz I I 2 3 4 5 6 7 8 g I0

B : I 1530.0 76.5 129.0 12B.B 124.0 120.B llb.5 113.3 109.7 107.0 101.5* 97.5*

2 1532.5 76.6 131.2 131.0 126.9 122.6 118.8 115.0 112.1 109.0 104.5 99,I *

I 3 1530.076.5 12B.9 128.5 123.9 120.2 115.0 112.2 108.3 105.9 100.5* 96.B*

4

IAverage 129.8 129.6 125.2 121,3 117.1 113.7 110.3 107.5 102.5 97.9

9 I I 1572.678.6 128.9 128.6 125.9 122,0 116.7 114.0 110.0 106.0 102.3* 102.0*

2 1575.078.8 131.5 130.9 128.5 124.8 120.5 117.3 115.1 112.1 108.3 106.2

i 3 1572.578.& 128.7 128.0 125.7 121,2 117.1 114.4 III.0 108.0 104.9 I01.8

I 4 1575.07B.B 132.1 131.2 129.0 125,2 121.3 117.1 I14.B 112.1 IOB.5 106.1

IAverage 130.6 129.9 127.5 123.6 119.4 116.0 113.3 110.3 106.7 104.5

10 I 1525.076.3 130.2 128.1 125.3 121,1 115.8 113.1 110.2 106.3 101.3* 97.2*

2 1525.0 76.3 132.0 130.5 127.6 123.3 119.1 115.2 113.1 II0.I 105.2 101.4*

3 1525.0 76.3 128.6 127.0 123.7 119,6 115.1 II0.8 IOB.B 105.5 101.2 95.6*

4 1527.576,4 132.2 131,4 12B.4 123.B 119.6 117,2 113,6 109,7 106.2 101.2*

Average 131.0 129.6 126.6 122.3 117.8 114.7 111.9 108.4 104.0 99.5

II I 1515.0 75.8

2 1515.0 75.8 110.6 109.1 101.3 92.9*

3 1515.0 75.8 10B.3 107.1 99.3 BB.O*

4 1515.0 75.8 III.0 II0.6 104.1 94.1*

:Average II0.I 109.2 102.0 92.3 NA NA NA NA NA NA

:

12 i I 1520.076.0 128.0 126.2 122.0 117.B 113.0 107.0 102.0 gAB J 93.0* 92.1*

I 2 1520.076.0 129.3 127.1 122.3 I18.0 112.9 107.4 103.1 95.6* 89.5* 90.9*

: 3 1520.076.0 127.1 124.8 120.1 115.7 110.3 104.9 I00I. 93.9. BB.O* 87.5*

I 4 1520.076.0 130.1 128.0 123.2 119.1 113.8 IOB.3 103.7 9&.6* 92.7* 90.B*

:Average 128.8 126.7 122.0 117.8 112.7 107.1 102.4 96.2 91.3 90.6

13 I I 1527.5 76.4 125.5 124.3 120.6 115.2 114.6 111.0 107.2 105.6 102.6 100.0

2 1537.5 76.9 125.5 126.1 123.1 119.6 116.3 113.3 111.0 109.0 106.2 103.8

3 1525.0 76.3 125.0 123.0 120.1 114.7 111.0 107.7 I05.0 102.2 99.7 97.3

l 4 1520.0 76.0 126.9 125.8 123.1 118.3 115.1 111.0 I08.0 105.2 102.1 99.9

IAverage 125.8 125.0 121.9 117.4 114,6 111.2 I08.3 106.2 103.3 100.9

:

14 I I 1527.576.4 123.5 123.2 121.3 117.9 115.1 111.1 109.0 107.0 103.9 102.0

: : 2 1537.576.9 128.0 126.3 123.2 119.9 117.2 114.2 III.I 108.2 106.3 104.1

: 3 1527.576.4 123.4 121.2 119.9 I15.B 113.6 109.5 106.5 104.7 101.3 100.2

• I 4

lAverage 125.5 124.1 121.7 118.2 115.6 112.1 109.3 106.9 104.3 102._

I ..................................................................................................................

• adjustedforBroadbandContributions NA NotAvailable

-123-
TABLE A. 1 (CONTINUED)

EXTERIOFRLUSH-MOUNTMICROP ED HO:NEPORTSIDE

Test ;Flight_ APM iBPF : HarmonicLevel,dOre20microPa

Condition:Number: : Hz : I 2 3 4 5 6 7 B 9 I0 Z

15 _ I 1527.5 76.4

2 1537.576.9 126.9 125.0 124.0 120.2 117.1 113.7 110.2 I08.3 I06.B 104.9

3 1527.576.4 122._ 123.4 120.0 116.8 113.1 110.3 107.4 105.2 102.0 99.9

4

_Average 125.2 124.3 122.4 I18.8 115.5 112.3 I09.0 I07.0 105.0 103.1

16 : I 1527.576.4

2 1540.077.0 125.B 127.4 124.3 122.2 117.3 115.8 113.0 111.2 108.2 105.7

3 1527.576.4 125.0 123.1 120.1 115.0 113.0 110.0 107.0 104.5 101.7 98.7

4

:Average 125.4 125.8 122.7 119.9 115.7 113.8 111.0 I09.0 106.1 103.5

17 I 1572.5 78.6

2 1570.07B.5 126.0 126.5 125.2 122.0 118.1 116.2 114.0 111.1 109.4 106.3

3 1570.078.5 123.4 123.4 121.5 11B.I 114.5 111.7 109.1 106.3 104.6 101.5

4 1570.078.5 126.2 127.1 125.2 121.6 IIB.I 115.0 112.6 110.1 108.1 105.0

Average 125.4 125.9 124.3 120.9 117.2 114.7 112.3 109.6 107.8 104.7

18 I 1522.5 76.1

2 1522.576.1 126.5 126.0 123.7 119.0 116.1 113.6 111.0 I08.? I05.B 103.1

3 1520.076.0 123.9 122.3 120.0 115.8 112.5 109.0 106.4 103.5 100.2 98.0

4 1517.575.9 126.9 125.B 123.0 119.0 116.6 113.2 110.1 107.2 103.9 101.7

:Average 126.0 125.0 122.5 118.2 115.4 112.4 109.6 107.1 103.9 101.4

* ad3ustedforBroadbandContributions NA NotAvailable

-124-
TAB LE A. 2

EXTERIOFRLUSH-MOUNMITECDROPHONE: STARBOARDSIDE

---%1i....!-iiiii-,T--iii--',T'iii........................ --- .........................

. Condition, Nulber: I Hz I 1 2 3 4 " 5 t 7 B 9 10

1 I 1 1525.076.3 131.0 127.5 122.5 116.0 110.8 104.8,99.5,

: 2 1520.076.0 129.4 126.4 120.6 114.2 109.4 I04.6, 103.5* 103.4, 102.6, 102.4*

3 1520.076.0 129.5 126.5 120.7 114.5 109.4 104.6, 103.2, 102.4, 102.1i 101.3,

: 4 1520.076.0 130.1 127.2 121.0 116.0 111.4 106.I, 102.3* 102.3, 101.9, lO0.B,

:Average 130.0 126.9 121.3 115.3 110.3 105.1 102.4 102.7 102.2 101.6

2 I 1570.07B.5 130.2 128.0 122.4 116.5 109.8* I07.B*lOB.l * 109.4* 108.6* 107.6*

2 1570.078.5 128.0 126.1 120.3 113.0 106.2* 108.2 108.7 I09.0 108.5 106.8

3 1572.578.6 128.5 126.2 120.9 113.0 106.7* 106.1* IOB.5 109.2 IOB.7 106.6*

4 1570.0 78.5 129.0 126.B 120.6 113.9 107.4* 108.4* I09.B* 110.5 110.1 I08.6*

Average 129.0 126.8 121.1 114.4 107.8 107.7 108.8 109.6 I09.0 107.5

3 I 1570.0 78.5 129.B 128.3 123.0 119.0 115.0 110.6 106.0 100.1, 96.0*

2 1570.0 7B.5 127.7 126.6 120.9 117.8 113.0 110.0 103.2* 99.6, 96.9,

3 1570.0 78.5 127.6 126.3 120.5 117.0 112.1 109.0 102.7* 100.3* 92.6*

4 1572.578.6 128.5 127.! 122.3 IIB.3 114.2 109.4 104.6* 101.2* 97.5*

:Average 128.5 127.1 121.8 118.1 113.7 109.8 104.3 100.3 96.1 NA

4 : I 1517.575.9 130.0 127.1 121.2 117.5 113.2 IOB.5 102.6* 98.3*

2 1520.076.0 128.5 126.0 120.3 116.4 112.9 107.4 101.2* 97.8*

: 3 1520.076.0 128.5 125.9 120.! 115.3 112.4 106.8 100.9t 97.1*

4 1517.575.9 129.0 126.2 120.7 116.3 112.7 107.2 I01.0* 99.4*

:Average 129.0 126.3 120.6 116.4 112.B 107.5 101.5 98.2 NA NA

5 { I 1532.5 76.6

: 2 1530.0 76.5 125.5 126.0 119.4 117.6 113.0 109.1 104.0 99.5i 93.3*

: 3 1530.0 76.5 126.1 126.2 120.0 117.4 113.0 108.5 103.7 97.7* 91.4*

4

;Average 125.B 126.1 119.7 117.5 113.0 IOB.B 103.9 98.7 92.5 NA

:

6 : l 1530.076.5 12B.I 126.6 122.0 119.1 I15.B 111.1 106.0 99.9, 98.0,

2 1532.576.6 125.8 IL_ 4=._ 120.9 116.6 114.0 lOB.B 105.0 I00.I * 94.B*

3 1532.576.6 127.0 125.2 121.0 118.0 115.2 109.0 105.7 100.7* 94.5*

4

IAverage 127.1 125.5 121.3 118.0 115.1 109.8 105.6 100.2 96.1 NA

7 : I 1530.0 76.5 130.I 127.6 121.6 11B.3 114.5 111.1 106.0 102.0* 9B.6*

- : 2 1530.076.5 128.0 126.0 121.0 116.8 113.5 I08.5 104.9 99.7* 98.0*

3 1530.0 76.5 12B.B 126.B 120.6 117.3 113.3 109.0 103.9 99.6* 94.0*

: 4

9

;Average 129.1 126.8 121.1 117.5 113.8 109.7 105.0 100.6 97.3 NA

.................................................................................

• adjustedfor BroadbanCdontributions NA NotAvailable

-125-
TABLE A.2 (CONTINUED)

EXTERIOFLRUSH-MOUNTMEICROP D HONE: STARBOARDSIDE

' lest IFlightI RPM :BPF : HarmonicLevel,dBre20microPa

Condition: NumberI l Hz l 1 2 3 4 5 6 7 8 9 10 -

8 I I 1530.0 76.5 127.9 127.7 121.6 119.3 114.3 110.5 105.0 100.7* 95.5*

I 2 1532.5 76.6 125.8 125.5 120.3 117.1 112.9 I08.3 103.4 97.6* 93.5*

I 3 1530.0 76.5 127.1 126.4 120.8 IIB.O 113.9 109.0 104.3 97.4* 94.2*

1 4

IAverage 127.0 126.6 120.9 118.2 113.7 109.4 104.3 98.8 94.5 NA

I

9 I I 1520.0 76.0 129.5 127.3 122.0 118.5 I14.9 110.2 104.4 101.2* 96.5*

2 1520.0 76.0 127.0 124.9 120.4 116.6 113.1 IOB.4 103.0 99.6* 94.8*

3 1520.0 76.0 128.0 125.9 120.8 117.5 113.6 108.4 103.0 98.6* 95.0*

4 1530.0 76.5 127.5 126.2 120.8 117.7 113.3 109.9 104.2 100.8* 95.5*

IAverage 128.1 126.2 121.0 117.6 113.B 109.3 103.7 100.2 95.5 NA

I

10 I I 1572.5 78.6 129.0 127.9 123.5 119.7 116.3 112.0 107.4 102.7* 99.7* %.3 *

2 1570.0 78.5 126.3 125.2 120.8 117.6 114.0 110.7 I06.0 102.4 9B.2* 95.6*

3 1572.5 78.6 127.8 126.7 122.0 118.3 115.2 110.6 106.5 101.9* 99.5* 95.6*

4 1572.578.6 128.1 126.4 122.B 118.5 115.9 112.1 106.5 104.0 99.2* 9B.3*

IAverage 127.9 126.7 122.4 118.6 115.4 111.4 106.6 102.8 99.2 96.6

11 I 1515.075.8 130.0 126.1 122.0 117.7 113.2 107.0 102.5 97.1 94.8* 92.2,

2 1515.0 75.8 127.8 124.6 120.0 116.1 111.5 106.4 100.0 96.4 94.2* 92.9*

3 1515.075.B 128.5 125.2 121.2 116.7 111.1 106.0 101.4 99.4 95.7* 93.7*

4 1515.075.8 128.6 125.5 121.4 117.0 111.7 106.1 101.8 100.3 96.5* 92.3*

:Average 128.8 125.4 121.2 116.9 112.0 106.4 101.5 98.6 95.4 92.B

12 : I 1520.076.0 112.5 102.8* 93.2*

: 2 1520.0 76.0 109.6 100.0* 91.3*

I 3 1520.076.0 110.2 101.4* 93.6*

A_-'..u7@.0

:Average 111.0 101.5 92.B NA NA NA NA NA NA NA

13 : I 1527.576.4 127.3 126.0 123.0 119.5 117.6 114.0 109.7 I08.2 104.9 101.3

I 2 1537.576.9 124.8 123.8 120.5 118.2 116.2 113.2 110.3 107.7 105.0 100.7

3 1525.076.3 126.0 123.9 121.2 118.8 115.1 112.1 IOB.8 106.2 103.1 99.5

I 4 1520.0 76.0 125.9 124.8 121.5 119.1 114.6 110.7 107.7 106.0 102.9 99.0

IAverage 126.1 124.7 121.6 118.9 116.0 112.7 109.2 107.1 104.1 100.2

14 I I 1527.5 76.4 125.B 126.6 122.9 120.2 117.7 113.7 111.0 IOB.I 104.8 102.2

I 2 1537.5 76.9 125.9 124.9 121.4 118.5 116.0 112.9 110.1 107.9 104.9 101.0

3 1527.576.4 124.4 125.0 121.6 118.5 115.9 112.3 109.3 107.0 102.6 100.2

IAverage 125.4 125.6 122.0 119.1 116.6 113.0 110.2 107.7 104.2 101.2

I

..................................................................................................................

• adjustedforBroadbandContributlons NA NotAvailable

-126-
TABLE A.2 (CONTINUED)

EXTERIOFRLUSH-MOUNT HICREDOPHON: STEARBOARDSIDE

- .... ........................ ii;iil;i-i;;;[;'ii-;;-ii-i;iii-i......................... ;

ConditionI NumbeIr I Hz _ 1 2 3 4 5 6 7 B 9 10

15 { I 1527.576.4 127.1 126.0 122.8 119.3 117.5 114.1 109.8 108.2 104.7 101.2

I 2 1537.576.9 124.5 125.1 121.2 119.0 116.0 113.5 110.3 107.8 104.7 I01.b

3 1527.576.4 125.0 124.1 121.2 118.0 116.1 112.4 109.2 107.2 103.0 100.4

4

{Average 125.7 125.1 121.8 118.8 I16.6 113.4 109.8 107.8 104.2 101.1

16 _ I 1527.576.4 126.7 126.0 122.7 120.2 117,5 114.0 111.1 I08.I 105.0 102.2

2 1540.077.0 124.9 124.0 121.4 119.5 117.2 114.0 111.0 108.1 105.6 102.6

3 1527.576.4 126.0 124.B 121.3 118.1 116.I 113.0 109.0 106.7 103.9 99.8

4

{Average 125.9 125.0 121.8 119.4 117.0 113.7 110.5 107.7 104.9 101.7

17 I I 1517.575.9 126.7 125.8 122.2 119.1 116.2 113.4 110.0 107.2 103.6 101.0

I 2 1517.5 75.9 124.6 123.7 120.2 117.8 115.5 112.4 I07.0 106.0 102.6 100.3

; 3 1517.575.9 125.3 123.4 120.4 117.3 115.0 111.5 101.5 105.9 102.2 98.2

4 1517.5 75.9 125.3 124.1 120.7 117.2 114.1 111.1 108.0 105.7 102.0 99.0

;Average 125.5 124.4 121.0 117.9 115.3 112.2 108.9 106.2 102.6 99.8

18 _ I 1575.078.B 127.1 12b.4 124.0 121.5 119.0 116.0 114.0 111.1 108.1 105.1

I 2 1572.578.b 124.3 124.8 121.9 119.5 118.3 115.0 113.2 110.2 107.8 105.3

3 1570.078.5 125.3 125.& 122.2 120.4 118.1 114.B 112.8 109.2 107.5 103.6

4 1572.578.6 125.4 125.0 122.5 119.8 117.4 115.0 111.B 109.3 107.1 103.2

{Average 125.6 125.5 122.7 120.4 118.2 115.2 113.0 110.0 107._ 104.4

..................................... . ............................................................................

* adjustedforBroadbandContributions NA NotAvailable
-128-
APPENDIX B

Interior Sound Pressure Levels at Harmonics of Propeller Blade

Passage Frequency: Flights 1 through 3, Bare Interior.

-129-
TABLE B. 1

CABINMICROPHONNUMBER E I : PORTENGINECOMPONENTS

.... ........................:::::::::::::::::::::::::::::......................... ::::

Condition_ Number: : Hz : I 2 3 4 5 6 7 B 9 I0

I 1 I 1580.0 79.0 112.2 97.7 86.7 69.4 65.0* 67.0* 54.2*

i 2 1572.5 78.6 112.2 95.7 92.8 77.4 76.2 79.2 73.1 61.5*

1 3 1572.5 78.6 111.5 93.5 89.2 70.3 * 67.5 * 65.7* 63.0 *

:Average 112.0 96.0 90.3 75.2 72.7 79.2 70.B 63.6 65.4 54.2

2 : I 1525.0 76.3 110.1 94.7 92.0 77.7 67.8 64.2* 63.0* 59.9* 61.8*

2 1525.076.3 109.9 92.0 83.8 75.B 70.3 61.9* 59.3*

: 3 1525.0 76.3 109.6 92.6 86.0 67.2. 61.5. 67.2. 64.2!

:Average 109.9 93.3 BB.7 75.3 &7.8 66.0 63.6 61.0 NA 60.7

=

3 : I 1527.576.4 110.6 88.B 75.5 85.3 81.1 80.1 73.7 67.2* 58.6*

2 1525.076.3 111.0 86.4 75.B 88.9 74.4 80.2 77.7 66.8, 65.2,

'. 3 1525.076.3 110.2 82.1 78.3 86.8 65.9* 77.1* 74.6* 69.5*

:Average 110.6 86.6 76.7 87.3 77.3 79.4 75.7 68.0 NA 63.0

4 = I 1572.578.6 113.5 88.I 8t.3 89.5 88.3 70.0, 67.2, 63.3, 61.7,

2 1572.57B.6 113.0 83.2 84.8 90.6 81.0 64.9* 64.1*

3 1572.5 78.6 113.7 80.5 83.7 91.5 81.5 78.5, 68.5,

:Average 113.4 85.1 83.5 90.6 85.0 76.1 67.1 63.3 64.1 61.7

9 : I 1572.5 78.6 113.7 86.4 79.0 89.6 75.9 80.7 78.7 62.9, 75.8

2 1575.0 78.8 113.2 92.6 85.2 90.6 68.9 75.7* 82.1 72.9* 72.8*

3 1572.5 78.6 113.6 92.9 83.7 87.7 70.0, 77.8* 81.5 69.8* 66.6,

:Average 113.5 91.5 83.3 89.5 72.8 78.6 81.0 70.1 73.1 NA

i

10 _ I 1525.0 76.3 110.3 93.4 75.B 85.0 71.7 80.7 78.2 70.1* 62.0*

2 1525.0 76.3 III.0 93.9 87.8 85.4 79.3 82.0 72.9. 65.8*

', 3 1525.0 76.3 I10.1 92.7 86.9 84.8 78.8 82.9 76.2 65.2 * 62.2 *

:Average 110.5 93.4 85.8 85.1 77.7 82.0 76.3 67.6 NA 62.1

Z

12 : I 1520.0 76.0 109.0 88.5 72.1 86.1 6B.0 78.0 70.2 58.6* 68.3 51.5,

2 1520.0 76.0 109.3 87.1 80.1 79.7 73.6 78.0 71.2 58.2* 59.1* 54.9*

3 1520.0 76.0 109.3 81.1 82.5 81.7 72.6 77.0 72.4 56.8* 57.7* 60.5*

:Average 109.2 86.5 79.9 83.3 72.0 77.7 71.4 57.9 64.3 57.2

17 : I 1572.578.6 107.0 83.8 88.0 79.5 78.5 82.3 75.7 74.3 78.3 60.1*

: 2 1570.078.5 106.7 90.7 88.9 76.3 76.2 81.7 73.9 76.4 76.4 67.1

: 3 1570.078.5 105.9 84.7 89.9 73.9 74.9 86.2 75.0 72.3 70.5 58.0* -

;Average 106.6 87.6 89.0 77.2 76.8 83.9 74.9 74.7 76.1 63.5

18 : I 1522.576.1 102.2 89.7 90.3 74.6 77.9 75.2 74.3 69.8 78.0 60.7*

: 2 1522.5 76.1 103.4 91.6 92.0 76.5 81.5 65.5. 74.1 69.5 79.2 54.0,

3 1520.0 76.0 102.6 90.4 92.9 76.0 76.1 76.1 69.3 55.8*

:Average 102.8 90.6 91.9 75.8 79.1 72.6 74.9 69.5 78.6 57.8

• adjustefor d BroadbandContributions NA NotAvailable

-130-
TABLE B. 2

CABINMICRDPHDNE NUMBERI : STARB0ARDENBINECOMPONENTS

--%1i....TIiiii-T-iIi--TiII--T........................ iITIII I-I- 7 iTii-T- -i-o-,-ii ......................... lI-i;

ConditionI NumbeIr I Hz I 1 2 3 4 5 6 7 8 9 10

...................................................................................................................... 1,

" l I 1 1525.0 76,3 103.4 96.7 94.3 83.5 68.2 63.1 * 64.0 * 55.2 *

I 2 1520.0 76.0 103,6 96.7 95.1 84.2 71.5 72.0

I 3 1520.0 76.0 103.1 95.1 96.3 84.0 72.4 68.I * 68.0*

IAverage 103.4 96.2 95.3 B3.9 71.0 66.3 69.2 55.2 NA NA

I

2 I 1 1570.0 78.5 105.4 95.2 91.6 84.9 77.9 66.1 * 56.0 * 59.1 ! 56.6*

l 2 1570.0 78.5 104.6 96.2 98.5 B0.4 73.2 67.3 * 58.2 *

3 1572.5 7B.6 104.1 92.3 90.5 80.5 76.2 67.5 *

IAverage 104.7 94.9 95.1 82.5 76.2 66.9 64.6 58.7 56.6 HA

3 l 1 1570.0 78.5 106.9 99.4 87.5 86.7 79.7 62.5 * 67.0 *

I 2 1570.078.5 107.2 98.5 90.2 87.9 80.5 64.B* 69.7* 61.2*

i 3 1570.0 78.5 105.2 95.B Bg.B BB.4 76.4 72.1* 65.2* 66.9* 63.1*

IAverage 106.5 98.I 89.3 87.7 79.2 69.5 65.0 68.I 62.3 NA

4 I I 1517.575.9 104.8 99.6 86.6 82.1 75.7 68.2* 61.1* 64.5, 60.0*

', 2 1520.0 76.0 I04.B 99.0 BB.7 82.3 79.3 67.8 * 70.5* 63.0*

I 3 1520,0 76,0 I03,B 96.6 B9,5 83.3 70.Be 6B,0*

lAverage I(14.5 98.6 88.4 82.6 76.5 68.0 68.0 63.8 NA 60.0

9 I I 1520.076.0 102.0 95.6 87.0 86.2 77.7 76.3, 71.2, 68.9* 57.3,

2 1520.076.0 102.3 92.4 89.4 89.2 78.3 72.5* 64.3* 66.4*

3 1520.076.0 102.5 91.1 89.5 85.7 69.5* 78.4*

IAverage 102.3 93.5 B8.B 87.3 76.5 76.4 69.0 67.8 NA 57.3

10 I I 1572.578.6 105.4 98.3 B4.B BB.6 86.6 79.4 72.3* 67.6* 68.3*

I 2 1570.078.5 105.3 95.8 87.5 88.9 81.8 Bl.l 6B.2* 70.3, 63.7* 57.9*

I 3 1572.5 78.6 !06.7 94.7 89.0 89.7 81.2 78.2 * 72.7* 67.(,*

:Average 105.8 96.5 87.4 89.1 63.9 79.7 71.5 68.5 66.6 57.9

11 I I 1515.075.8 101.2 85.3 B3.B 82.0 76.1 80.9 70.5 57.7, 59.7* 60.9,

I 2 1515.075.8 102.0 86.4 85.0 84.7 73.3 77.7 64.1* 63.4* 50.2*

3 1515.075.8 100.9 83.1 88.2 79.9 65.1* 82.9 72.2 66.0* 62.5* 63.7,

IAverage 101.4 85.1 86.1 82.6 73.4 81.0 70.1 63.6 62.1 60.9

I

17 I I 1517.575.9 94.3 BB.3 87.2 B3.B 77.4 81.B 78.0 73.0 71.0 58.5*

2 1517.575.9 96.4 87.7 90.3 83.5 75.1 78.9 60.1* 71.0* 63.5* 60.6*

I 3 1517.575.9 94.4 89.5 B9.3 72.3 73.0 82.4 76.1 70.0 66.0*

• IAverage 95.1 BB.6 89.1 82.0 75.5 81.3 75.4 71.5 68.0 59.7

18 I 1575.07B.B 99.0 94.6 87.2 91.4 83.6 89.3 78.I 72.3 69.5 67.6

2 1572.5 78.6 98.5 95.8 89.7 89.2 86.3 89.0 81.2 72.1 71.1 68.9

3 1570.078.5 99.6 94.8 89.0 83.0 83.7 BI.B 75.1 69.7 62.0* 67.1

Average 99.1 95.1 88.8 89.1 84.7 87.8 7B.B 71.5 68.9 67.9

.................................................................................

• adjustedforBroadbandContributions NA NotAvailable

-131-
TABLE B. 3

CABINMICROPHONE NUMBERI : PORT& STARBOARDENGINECOMPONENTS

' Test ;Flight : RPM ; BPF : HarmoniLcev. ;], dBre-'_O-i;;ro-P......................... a

Condition_ Number_ _ Hz _ I 2 3 4 5 6 7 B 9 10

5 : I 1532.5 76.6 111.3 93.3 87.3 92.3 81.1 79.3 69.4* 66.8* 66.6.

; 2 1530.0 76.5 110.8 83.2 84.2 90.3 82.6 84.2 70.3* 67.2* 72.8 60.8*

; 3 1530.0 76.5 111.7 91.4 85.4 81.4 73.4 86.B 75.2 71.4, 66.4,

=Average 111.3 90.9 85.8 89.9 80.4 84.4 72.4 69.0 70.7 64.4

6 I 1530.076.5 107.8 100.5 B2.B 90.5 82.1 87.2 81.3 65.4* 72.8 60.3

2 1532.576.6 107.6 99.5 91.5 87.9 81.1 79.9 78.0 72.6* 70.4* 62.0*

3 1532.5 76.6 107.6 98.8 91.4 90.3 80.8 85.6 79.0 64.4t 66.1* 67.8*

Average 107.7 99.7 90.0 89.7 81.4 85.2 79.7 69.1 70.6 64.6

7 I 1530.076.5 113.6 97.3 87.4 87.8 76.9 86.2 79.B 70.3* 65.8*

2 1530.076.5 113.6 92.0 92.1 92.2 74.9 81.5 77.2 64.8* 71.2* 58.3*

3 1530.076.5 114.0 92.7 93.0 90.3 BO.O 86.0 74.4* 67.0* 66.0* 68.8*

;Average 113.7 94.7 91.4 90.5 77.8 85.0 77.7 68.0 68.4 66.2

8 '. I 1530o0 76.5 112.5 93.0 87.7 81.9 78.2 86.1 79.3 74.8 68.2* 66.7*

; 2 1532.5 76.6 113.1 93.9 90.3 87.9 79.1 85.1 76.0 69.0* 70.0* 58.I *

3 1530.0 76.5 113.0 96.7 93.0 83.3 82.0 84.0 76.1 67.2*

;Average 112.9 94.9 90.9 85.2 80.I 85.2 77.4 71.6 69.2 64.3

13 : I 1527.5 76.4 105.2 97.2 88.5 84.4 80.9 83.6 78.0 75.4 74.6 65.1

2 1537.5 76.9 102.0 95.1 89.3 86.3 79.0 90.4 81.9 75.1 76.1 66.2

3 1525.0 76.3 104.7 99.0 86.3 83.1 80.4 79.0 83.1 70.0 63.4* 58.7*

IAverage 104.2 97.4 88.2 84.8 80.2 86.7 81.5 74.1 73.8 64.3

14 : I 1527.576.4 103.1 BB.I 90.5 84.9 80.3 83.9 84.1 75.3 72.6 69.0

I 2 1537.576.9 106.6 97.0 93.2 85.9 84.0 91.2 81.4 77.1 73.7 65.3

3 1527.5 76.4 103.3 83.7 91.7 83.1 74.0 79.1 81.0 72.0 67.2, 60.5.

lAverage 104.6 92.9 91.9 B4.B 81.1 87.4 82.4 75.3 71.9 66.2

I

15 _ I 1527.5 76.4 102.9 85.7 90.6 81.9 83.8 82.1 82.2 71.2 76.0 63.0*

; 2 1537.5 76.9 104.2 84.7 89.4 88.I 77.8 92.5 82.9 75.3 76.0 66.1

3 1527.5 76.4 99.2 95.1 90.6 83.1 76.7 81.1 81.0 68.0, 64.6* 60.6*

:Average 102.6 91.1 90.2 85.2 80.6 88.4 82.1 72.5 74.4 63.8

:

16 : I 1527.576.4 105.9 95.8 90.7 86.6 79.9 83.0 82.0 77.1 72.0 68.7

2 1540.0 77.0 101.4 97.5 93.5 85.9 83.7 92.3 82.5 73.9 75.1 68.3

3 1527.5 76.4 105.2 97.9 91.6 78.5 81.9 82.2 80.0 71.5 67.5. 60.9.

IAverage 104.6 97.2 92.1 84.9 82.1 BB.4 81.6 74.B 72.5 67.1 :

.......................................................................................................

• adjustefdorBroadbanCdontributions NA NotAvailable *

-132-
TABLE B.4

CABINMICROPHONE NUMBER2 : PORTENGINECOMPONENTS

.... ........................ .........................

ConditionI NumberI l Hz l 1 2 3 4 5 6 7 8 9 I0

I I I 1580.0 79.0 112.2 93.8 90.7 76.2* 74.6* 73.9* 69.7*

2 1572.5 7H.6 111.7 93.2 H7.6 86.H 77.8 78.9 63.1* 71.2* 63.3. 61.1*

I 3 1572.5 78,6 111.6 91.5 89.4 87.4 75.7 76.2 64.6* 70.0* 64.5*

IAverage 111.8 92.9 89.4 85.5 76,2 76.8 66.8 70.6 63.9 61.1

2 I I 1525.0 76.3 110.6 89.2 85,4 78.3* 65.4* 74.6* 64.3* 68.8*

2 1525.0 76,3 109.9 86.9 83,7 85,5 72.2* 71,8* 72.4*

3 1525.0 76,3 110.2 82.5 85.7 83,0 70.7* 70.8* 70.2*

IAverage 110.2 87.0 85,0 83.2 70.3 72,7 64.3 70.7 NA NA

3 ] I 1527.5 76,4 II0.9 96,5 95.2 85.9 83,5 77.7* 70,6* 68,4*

I 2 1525.076,3 110.9 97.0 93.6 88,I 84,4 71.7,

3 1525.076.3 110.9 94,8 91.4 89.6 81.7 70.0,

IAverage 110.9 96.2 93.7 88.1 83.3 74.5 70.6 NA NA 68.4

I

4 i I 1572.5 78.6 112o.. 95.1 0.4.5 94.6 87.5 82.1 69.4* 68.0*

2 1572.5 78.6 112.5 94.6 92.4 95.1 83.1 84.7 72.6* 69.4a 69.8*

I 3 1572.5 78.6 113.7 92.9 93.0 96.2 86.2 82.3 77.0 70.7, 72.0,

lAverage 113.1 94.3 93.4 95.4 86.0 83,2 74.1 70.1 70.2 HA

I

Q ; I IJ,_._ =_ = 78,6 112.8 96.7 94.4 92.7 85,0 84,3 73.6, 69.6,

I 2 1575.0 78,8 112,3 96.9 92,8 91.7 87,2 90.0 75.8 69.5, 74.2 70,9.

3 1572.5 78.6 113.2 99.4 92,8 90,8 86,8 8B.0 75,6* 66,8* 75.3 64,8*

IAverage 112.8 97.8 93.4 91.8 86.4 88.0 75.1 68.4 73.6 68.8

I

10 : I I_.0 _ 76.3 110.3 99.1 95.6 83.7 76.4 79.1* 71.9' 67.1*

2 1525.0 76,3 110,4 98.7 93.6 71,4* 84.7 85.0 73,7* 71.9* 71,2*

l 3 1525.076.3 110.2 98.8 92,4 78.6 82.4 84,2 71,5* 72,7* 67.6*

IAverage 110,3 98,9 94.1 80.3 82,3 83,4 72.5 72.3 NA 69,0

I

12 I I 1520.076,0 109.1 97.2 93,3 84.9 72,0 71.0, 67,0, 62,1* 62.5,

l 2 1520.0 76.0 109.0 96.8 89.1 83.0 77.7 78.3 71.2 62.5,

I 3 1520.0 76.0 109.6 96.5 89.8 84,3 74,6 79.8 70.9 66.3, 59.1* 63,5*

IAverage 109.2 96.8 91,1 84.1 75.4 77.7 70.1 64.8 60,9 63.0

,,

17 _ I 1572.5 78.6 105.7 92.3 87.6 81,6 86.6 8%0 84,6 74,9 73.3 75.0

l 2 1570.0 78.5 105.1 90.3 84.2 83,8 84.4 89,1 82.8 71,9 72.5 77.1

Q 3 1570.0 78,5 104,9 91,6 88.3 83.9 81.7 89.6 82.7 70.0 73,3 74.2

" lAverage 105.2 91.5 87.0 83.2 84.7 89.2 83.5 72.7 73.0 75.6

f

. 18 I I 1522.5 76.1 I01.9 93.9 83,0 87.2 82.1 86,0 73,9 68.5* 65.5*

: 2 4aa,.._ =_9 = 76.1 102.9 94.5 82.8 87.1 79.4 85.0 73._ 70.8 _ _

I 3 1520.0 76.0 102.3 94,1 70,3 84.B 83,3 82.4 70,5 69,8* 62,9,

_Average 102.1 94.2 81.3 86.5 81.9 84.7 73.0 69.8 HA 64,1

• adjustedforBroadbandContributions NA NotAvailable

-133-
TABLE B. 5

CABINMICROPHONNUEMBER2 : STARBOAERDNGINECOMPONENTS

.... ........................ .........................

Conlition_ Number_ I I,, _ I 2 3 4 5 6 7 8 9 10

I _ I 1525.0 76.1 102.7 90.1 81.5 82.7 78.2

2 1520.0 76.0 102.2 91.1 80.6 79.3 80.2

3 1520.0 76.0 102.4 89.4 78.6 82.9 79.7

_Average 102.4 90.3 10.4 81.9 79.4 NA NA NA NA NA

2 i I 1570.0 78.5 104.3 91.8 84.9 88.0 78.8 69.7*

2 1570.0 78.5 103.3 92.4 85.9 80.3 81.2 70.1* 65.0*

3 1572.5 78.6 103.2 93.4 85.0 79.9 76.5 65.2,

€Average 103.6 92.6 85.3 84.4 79.2 69.7 68.3 65.0 NA NA

3 I 1570.0 7B.5 105.9 92.6 74.2 86.8 83.4 70.2* 72.5* 67.3*

2 1570.0 78.5 105.5 93.7 80.7 87.5 74.6* 79.9* 65.3*

3 1570.0 78.5 104.1 94.0 70.3 16.7 82.0 75.9* 64.1*

Average 105.2 93.5 77.1 87.0 81.3 76.9 70.2 67.3 64.1 NA

4 I 1517.5 78.9 103.6 95.7 86.6 85.2 80.5 65.5* 68.5*

2 1520.0 76.0 102.9 94.9 86.4 86.7 87.9

3 1517.5 75.9 102.0 93.6 84.5 85.5 Bl.O 66.7*

_Average 102.9 94.8 85.9 85.8 84.5 NA 66.1 68.5 NA NA

i

9 i 1 1520.0 76.0 98.7 92.7 89.1 89.5 84.8 79.7* 64.9* 68.2*

2 1520.0 76.0 99.1 88.7 86.8 89.7 83.0 75.8, 69.0,

3 1520.0 76.0 99.7 gl.£ 88.2 88.8 77.9 82.1 69.4*

_Average 99.2 91.4 88.1 89.4 82.7 79.9 64.9 68.9 NA NA

Z

I0 _ I 1572.5 78.6 102.5 93.5 83.0 89.7 90.1 81.7

2 1570.0 78.5 102.7 92.7 85.9 87.8 87.6 82.6 67.9*

3 1572.5 78.6 104.6 96.8 83.8 88.5 86.4 80.0 73.3* 65.2*

_Average 103.4 94.7 84.4 88.7 88.3 81.6 71.4 NA 65.2 NA

II _ I 1515.0 75.8 99.5 90.2 81.5 83.8 84.6 80.9 66.2* 63.4* 67.9.

i 2 1517.5 75.9 99.6 88.2 82.3 84.3 84.7 81.3 61.5* 62.7* 61.6, 61.5,

; 3 1515.0 75.8 98.3 87.9 85.1 82.0 79.3 82.1 59.0, 59.5, 64.4, 60.6,

IAverage 99.2 88.9 83.3 83.5 83.5 81.5 63.3 62.2 63.2 64.6

17 I 1517.5 75.9 87.1 84.5 90.3 18.8 82.7 92.1 85.0 80.0 64.5*

2 1517.5 75.9 89.8 89.8 90.3 86.8 82.0 90.6 83.1 76.4 65.8* 61.5*

3 1517.5 75.9 89.6 89.1 85.9 84.2 69.2 87.2 80.0 77.0 56.5*

Average 89.0 88.3 89.3 87.0 80.7 90.4 83.2 78.I 65.2 59.7 :

18 I 1575.0 78.8 95.3 87.0 87.0 91.7 84.1 90.4 82.7 80.0 69.6* 64.2, ,

2 1572.5 78.6 94.4 89.8 82.7 88.I 87.5 90.0 81.3 8n.2 66.0* 70.8

3 1570.0 78.5 96.5 89.0 83.2 87.3 86.3 88.3 72.8 75.0 73.1 68.9

IAverage g5.5 88.8 84.8 89.5 86.2 89.7 80.5 79.0 70.5 68.7

I

..................................................................................................................

• adjustedforBroadbandContributions NA NotAvailable

-134-
TABLE B.6

CABINMICROPH0t NU_MBER2 : PORT_ STARBOARD ENGINCOE RPDNENTS

.... .... ........................ ....................... :

Condition: Numbe:r : Hz : 1 2 3 4 5 6 7 B 9 10

5 : 1 1532.5 76.6 110.8 96.9 67.5 8%0 80.1 95.0 71.9! 69.9! 66.5e 66.5e

" : 2 1530.0 76.5 110.6 97.4 BB.4 87.7 81.4 83.2 75.0 70.2 _ 70.0,

I 3 1530.0 76.5 111.8 99.9 BB.B 90.3 85.6 80.9 73.9e 73.7t 67.4 ,

IAverage 111.1 98.3 88.3 89.1 83.0 83.3 73.8 71.6 66.5 68.2

I

6 I I 1530.0 7b.5 108.8 101.3 95.1 09.8 97.6 86.0 78.1 75.6, 65.9* 65.2t

I 2 1532.5 7b.6 109.2 98.7 93.9 87.4 76.2 87.7 76.1 67.5e

I 3 1532.5 76.6 108.9 102.1 92.1 85.6 86.9 _.0 78.3 74.3* 68.4*

:Average 108.6 100.9 93.9 87.9 85.6 87.3 77.6 73.6 65.9 67.1

I

7 I 1 1530.0 76.5 112.8 92.1 93.8 BB.i 02.4 02.7 72.9o 76.2t 69.5,

l 2 1530.0 76.5 112.5 96.4 96.5 87.7 88.7 87.5 74.0 t 76.0 * 71.1*

I 3 1530,0 76.5 113,4 95,7 95,1 84,6 61.9 88,6 73.0 e 78.7 67.9*

:Average 112.9 95.1 95.3 87.1 85.5 86.9 73.3 77.1 NA 69.7

I

8 : 1 1530,0 76.5 112.3 101.1 93.6 85.9 88.7 78.7o 71.1 t 71.7 t 67.7* 67.3t

: 2 1530.0 76.5 112.0 100.3 93.4 88.5 89.3 85.7 73.3* 73.2t 66.8* 69.4*

[ 3 1530.0 76.5 112.7 103.4 95.6 89.1 85.4 88.1 69.9 z. 73.0* 65.8*

IAverage 112.3 101.8 94.3 88.0 88.1 65.6 71.6 72.7 67.3 67.8

I

13 : 1 1527.5 76.4 103.5 94.3 87.6 91.3 87.2 92.7 B5.i 77.5 73.1 69.4*

I 2 1537.5 7b.9 100.9 86.4 87.3 07.5 85.4 88.9 03.4 75.1 71.2 65.4*

I 3 1525.0 76._ 103.1 97.7 88.3 89.9 82.9 89.3 91.5 71.0 67.7 62.0*

:Average 102.6 94.8 67.8 89.8 85.5 90.7 83.6 75.3 71.2 66.6

I

14 : I 1527.5 76.4 103.4 94.3 87.0 92.8 83.2 92.1 83.0 80.0 68.7 60.8 *

: 2 1537.5 76.9 104.1 96.2 86.7 84.1 77.4 85.8 81.2 7B.B 73.0 59.0*

3 1527.5 76.4 103.4 91.4 04.4 92.0 84.3 83.9 79.6 78.5 68.1 63.9 *

:Average 103.6 94.4 86.2 91.0 82.5 BB.7 81.5 79.1 70.5 61.7

15 _ 1 1527.5 76.4 100.9 93.2 91.3 89.2 84.7 91.5 03.1 75.5 70.5 67.9

I 2 1537.5 76.9 103.6 95.0 93.2 93.4 75.4 85.0 64.1 75.9 72.9 63.2 *

: 3 1527.5 76.4 99.8 91.5 84.0 88.3 B4.6 84.3 78.0 75.7 68.1 58.6 z.

IAverage iOi.7 93.5 87.8 90.9 83.1 88.2 82.4 75.7 70.9 64.8

I

i6 I 1 1527.5 76.4 i04.3 92.9 90.3 92.8 85.1 92.i 82.6 76.4 70.4 65.7 *

I 2 1540.0 77.0 i01.2 92.4 86.1 9i.1 94.2 BS.B 85.0 77.i 75.3 64.2,

: : 3 1527.5 76.4 103.3 98.3 86.5 67.5 82.3 86.5 O0.I 75.4 69.1 58.0t

:Average 103.1 95.4 BB.l 91.0 84.0 89.1 83.0 77.1 72.5 64.2

• adjustedfor BroadbandContributions NA NotAvailable

-135-
TABLE B.7

CABINMICROPHONENUMBER3 : PORTENGINECOMPONENTS

Test I FlightI RPM IBPF I HarmonicleveX,dBre20microPa

Conditiont NumbeIr I Hz I 1 2 3 4 5 6 7 8 9 10 ."

............................................. . ........................................................................

1 I 1 1580.0 79.0 106.5 95.0 93.B 71.6* 78.0

2 1572,5 7B,6 105.8 89,9 95,0 BO,O 76,8 69,9 * 72,2 * 68,8 * 68,1 * 6B.0*

3 1572,5 78,6 106,6 92,3 94,3 7B,0 81,2 67,1 * 67,2 *

IAverage 106,3 92,9 94,4 77,7 79,1 68,7 70.4 6B,B 6B,1 68,0

2 I 1 1525,0 76,3 1(:)3,6 89,5 9B,1 BO.B 79.5 73,2* 6B,9* 71.2*

2 1525.0 76.3 102.4 92.3 97.1 75.7 75.B 74.8*

I 3 1525.0 76.3 103.2 89.3 95,6 73.4 77.2 68.4,

IAverage 103.1 90.6 97.1 77.8 77.8 72.9 68.9 71.2 NA NA

I

3 I I 1527.5 76.4 102.5 93.9 97.9 82.4 71.9* 75.1*

2 1525.0 76.3 100.1 98.7 97.0 83.7 81.2 75.6*

3 1525.0 76.3 98.7 97.8 95.7 84.5 81.0 65.5* 79.1 6B.0*

:Average 100.7 97.2 97.0 83.6 79.6 65.5 77.0 68.0 NA NA

I

4 ; I 1572.5 78.6 99.7 87.1 98.7 76.8 77.7 78.0*

2 1572.5 78.6 97.4 85.0 9B.6 80.7 82.4 82.1 67.2* 76.9*

3 1572.5 78.6 94.2 84.5 98.7 81.6 84.4 78.0* 68.3* 77.0*

IAverage 97.6 85.7 98.7 80.1 82.3 79.B 67.8 77.0 NA NA

9 I I 1572.5 78.6 BB.1 90.5 99.0 87.7 86.4 84.0 72.8* 67.2, 75.4,

', 2 1575.0 78.8 86.8 91.1 97.2 89.0 83.6 73.6* 81.1 70.3* 81.8

; 3 1572.5 7B.6 B7.4 97.0 97.3 8B.0 85.3 77.1* 79.0 70.I* BO.O

IAverage 87.5 93.9 97.9 BB.3 85.2 60.4 7B.B 69.4 79.B NA

I

10 I 1 1525.0 76.3 101.2 9B,0 96.7 BB,8 B0.9 77.9* 79.5*

2 1525.076.3 101.1 99.6 93.4 BB.3 82.9 85.7 76.9* 74.3, 68.9*

', 3 1525.076.3 99.6 100.0 92.4 87.7 76.6 84.0 71.2* 74.5*

IAverage 100.7 99.3 94.6 BB.3 80.8 83.6 77.0 74.4 NA 68.9

I

12 ; I 1520.076.0 102.0 96.7 92.0 83.7 69.7 77.2 72.3*

2 1520.076.0 101.5 96.2 84.1 72.1 76.8 80.5 70.3* 66.4*

3 1520.076.0 101.4 97.3 87.3 74.3 77.3 79.6 69.6* 72.2* 64.0* 63.5*

IAverage 101.6 96.8 89.0 79.7 75.7 79.3 71.2 71.4 64.0 65.2

17 I 1 1572.578.6 97.0 96.5 84.5 82.B 72.4 90.3 79.4 81.5 B2.9 75.2

l 2 1570,0 78,5 96,9 98,3 83,4 84,1 82.5 91.3 B3,2 83.2 80,1 69,7*

l 3 1570.078.5 96.2 95.6 82.4 84.6 73.6 90.0 75.3 76.4 76.2 68.9* ;

IAverage 96.7 96.9 83.5 83.9 78.6 90.6 80.4 Bl.l B0.5 72.2

d

18 I 1 1522,5 76,1 99,2 94,8 86,0 85,6 77,7 81,1 79,1 65,6 * 67.6*

l 2 1522.576.1 98.7 95.0 83.8 B4.5 73.8 81.0 76.3 67.3* 65.3*

3 1520.076.0 99.2 95.2 84.6 84.7 74.0 81.1 76.5 69.0, 70.5,

:Average 99.0 95.0 84.9 85.0 75.6 81.1 77.5 67.5 NA 68.3

......... ...........

-136-
TABLE B,B

CABINMICROPHONE NUMBER3 ."STARBOARDENGINECOMPONENTS

.... ........................ ................

Conditio:nNulberI : Hz : I 2 3 4 5 6 7 B 9 I0

I : I 1525.0 76.3 93.5 98.3 98.7 81.0 81.3

i 2 1520,0 76,0 94,2 I00.6 9B,4 82.2 B3,B 70,7* 71,3* 74,4*

: 3 1520.0 76.0 91.7 97.7 99.5 85.9 84.2 72.B,

IAverage 93.3 99.1 98.9 83.6 83.3 71.9 71.3 74.4 NA NA

2 I I 1570.0 78.5 89.4 95.6 96.1 85.6 80.2 69.2* 70.0*

: 2 1570.078.5 89.6 97.3 101.5 90.0 83.5 73.6 72.0*

3 1572.5 76.6 85.5 94.8 94.9 83.6 80.3 66.0* 71.2*

:Average 88.5 96.0 98.5 87.2 81.6 70.7 71.1 NA NA NA

I

3 : I 1572.5 78.6 96.7 100.6 92.0 85.5 83.2 75.2, 71.2,

2 1570.0 78.5 98.0 99.9 94.7 85.3 89.6 82.0 70.2*

3 1570.0 78.5 95.1 89.6 91.4 86.9 82.B 84.7 68.7* 73.0,

IAverage 96.B 98.7 92,9 86,0 86,4 82,1 70,2 73,0 NA NA

i

4 i I 1517.5 75.9 98.1 100.9 93.8 81.B 89.2 76.9.

'. 2 1517.575.9 97.9 101.7 94.3 72.3 94.7 72.7*

3 1517.575.9 98.4 96.5 94.0 75.0 89.3 73.7* 68.2*

:Average 98,I 100,2 94,0 78,2 91,9 74,8 68.2 NA NA NA

i

9 : I =u_,J..) 76.0 IL:..J 99.2 95.1 B5.B 91.7 82.9

: 2 1520.076.0 100.8 98.9 92.7 76.6 90.5 7b.7

: 3 1520.076.0 100.3 97.3 92.4 79.2 83.1 73.5*

:Average 101.3 98.5 93.6 82.3 89.7 79.4 NA NA NA NA

I0 I 1572.578.6 103.4 9B.6 92.8 81.6 90.5 81.3 79.0

2 1570.078.5 99.6 98.I 93.4 84.0 84.9 81.4 79.7 67.3* 68.2* _7.9*

3 1572.578.6 101.1 97.7 91.8 84.6 77.8 80.0 80.6

Average 101.7 98.I 92.7 83.6 87.0 80.9 79.8 67.3 68.2 67.9

11 I 1515.075.8 95.2 94.7 90.9 79.9 BB.B 86.0 68.2* 71.9, 65.5, 71.7

2 1515.075.8 96.5 96.3 90.3 78.9 BB.O 81.6 71.9 65.1* 70.8,

3 1515.075.8 99.7 92.9 91.1 83.1 81.0 79.0 71.4, 70.8* 63.7, 64.0,

Average 97,6 94,9 90,8 81,0 B7.0 83,2 70,8 70.1 67,B 69,4

17 I 1517.5 75.9 97.4 92.6 B4.2 79.1 8B.4 96.1 82.0 66.8* 77.5

2 1517.5 75.9 96.3 91.8 85.7 72.3 Bg.B 97.3 85.1 82.2 74.1* 72.5,

, 3 1517.5 75.9 94.7 88.9 79.2 76.9 83.0 93.1 82.3 70.0* 65.5*

IAverage 96.3 91.4 B3.B 76.9 87.9 95.8 83.4 77.8 74.5 72.5

I

. IS I I 1575.0 7B.B 9B.B 93.4 86.5 7B.6 86.0 92.5 91.2 85.2 79.0 73.1

2 1572.5 78.6 97.8 95.6 86.2 80.6 88.5 94.2 90.7 88.0 69._* 74.0

: 3 1570.0 78.5 98.3 93.2 85.3 78.3 85.9 91.3 89.7 85.3 79.2 75.1

IAverage 98.3 94.2 86.0 79.3 87,0 92,8 90,6 86,4 77.6 74.1

..................................................................................................................

• adjustedforBroadbandContributions NA NotAvailable

-137-
TAB LE B. 9

CABINMICROPHONENUMBER3 : PORT& STARBOARDENBINECOMPONENTS

Test : Flightl RPM IBPF I HarmonicLevel,dBre20 microPa

Condition=NumbeIr l Hz 1 ! 2 3 4 5 6 7 B 9 10

5 I 1 1532.576.6 105.2 101.4 92.2 91.1 91.6 83.0 77.9,

1 2 1530.0 76.5 100.8 102.2 94.1 91.2 90.0 82.7 73.8* 69.7* 68.7* 71.1*

3 1530.076.5 100.8 101.2 86.2 79.1 87.5 87.1 72.2* 73.7*

=Average 102.8 101.6 91.9 89.5 90.0 B4.B 75.3 72.1 68.7 71.1

6 1 I 1530.0 76.5 108.3 99.B 97.1 91.1 91.B 85.0 76.9, 70.5,

2 1532.5 76.6 106.7 99.6 96.2 90.7 92.1 84.1 73.3* 74.7, 69.5* 73.1*

3 1532.5 76.6 106.5 103.0 95.2 90.3 87.6 84.4 75.1, 75.8* 67.2* 72.1,

IAverage 107.2 101.1 96.2 90.7 90.9 84.5 75.3 74.2 68.5 72.6

7 I 1530.0 76.5 104.7 96.0 96.4 92.7 90.3 86.0 69.5* 76.7*

2 1530.0 76.5 105.8 98.4 98.0 90.6 90.0 83.0 74.6* 75.1* 75.1* 73.7*

3 1530.076.5 103.0 95.2 95.6 90.4 81.8 86.9 71.7* 7B.3* 68.2*

Average 104.6 96.8 96.8 91.4 88.7 85.6 72.4 76.9 75.1 71.8

B I 1530.076.5 102.2 103.5 94.1 86.6 92.2 88.0 77.5* 75.6*

2 1530.076.5 92.9 I04.1 94.0 86.4 92.6 86.0 76.2* 70.3* 71.7* 70.1*

3 1530.076.5 93.7 105.0 96.1 86.3 87.9 82.5 74.2* 74.2* 72.0* 69.5*

IAverage 98.4 104.2 94.8 86.4 91.4 86.0 76.2 73.9 71.9 69.8

13 l I 1527.5 76.4 98.8 85.7 85.7 83.2 86.9 96.0 79.1 74.1 78.9 71.1

2 1537.5 76.9 103.2 100.9 89.8 86.1 89.9 96.6 85.1 82.2 75.1 73.2

3 1525.0 76.3 97.0 96.2 83.9 83.0 83.6 93.2 80.2 7B.9 75.0 70.1*

_Average 100.5 97.5 87.2 84.3 87.5 95.5 82.3 79.5 76.7 71.7

14 i I 1527.5 76.4 97.1 97.9 90.4 86.4 BB.6 95.0 85.0 74.9 78.5 70.4

l 2 1537.5 76.9 101.2 84.7 92.9 86.5 92.0 97.8 86.2 83.7 77.2 76.1

'. 3 1527.5 76.4 96.2 95.6 88.I 88.7 85.2 92.6 82.4 80.2 73.9 73.7

IAverage 98.7 95.3 90.9 87.3 89.4 95.6 84.8 80.9 76.9 74.0

15 l I 1527.5 76.4 104.1 100.4 79.3 84.2 88.7 98.3 81.3 72.7 73.7 72.3

l 2 1537.5 76.9 93.7 99.2 91.2 85.8 92.5 95.2 80.2 85.3 78.0 72.1

3 1527.5 76.4 103.4 99.0 89.3 86.9 82.9 93.1 86.0 BO.O 72.2* 74.1

IAverage 102.2 99.6 BB.B 85.8 89.6 96.1 83.3 BI.B 75.4 72.9

l

16 _ 1 1527.5 76.4 95.5 95.3 85.2 86.4 BB.B 96.0 86.2 75.6 B0.5 72.2

I 2 1540.077.0 104.2 101.3 92.4 85.6 90.5 97.2 86.0 84.4 78.0 75.0

I 3 1527.576.4 98.7 93.1 87.7 85.6 83.0 93.0 83.0 77.1 71.4* 75.0

IAverage 100.9 98.0 89.5 85.9 BB.4 95.7 85.3 80.8 7B.0 74.3 -

• adjustefdorBroadbanCont d ributions NA NotAvailable w

-138-
TABLE B. 10

CABINMICROPHONE NUMBER4 : PORTENGINECOMPONENTS

• Test I Flight I RF'M : BPF I Harmonic. Level,dBre 20microPa ..............

ConditionI NumbeIr I Hz l 1 2 3 4 5 6 7 8 9 10

I I 1580.0 79.0 108.5 89.7 83.1 78.8 76.2 70.2 *

2 1572,5 78.6 107.4 90,2 83.2 88.1 81.0 78,9 72.6* 69.9*

. 3 1570.078.5 108.8 86.0 82.8 78.1 81.6 73.1* 72.3*

Average 108.3 89.0 83.0 84.2 80.2 73.1 75.4 72.6 69.9 NA

2 1 1525.0 76.3 102.4 94.2 87.5 78.5 71.0* 75.4*

2 1525.0 76.3 100.4 95.8 87.5 79.2 76.1 69.4*

3 1525.076.3 103.5 92.5 80.4 79.5 74.1 75.8*

Average 102.3 94.4 86.1 79.4 76.6 71.0 74.3 NA NA NA

3 I 1527.576.4 95.1 100.8 82.4 83.9 81.6 70.6* 74.2* 77.0*

2 1527.576.4 97.3 102.3 84.1 79.4 78.0 70.2* 78.3*

3 1522.5 76.1 98.1 101.2 80.9 83.1 80.2

iAverage 97.0 101.5 82.7 82.5 80.2 70.4 76.7 77.0 NA NA

4 l 1572.5 78.6 106.4 102.5 79.8 85.2 83.2

2 1572.5 78.6 106.2 101.4 80.5 87.8 80.3 74.3*

3 1572.5 78.6 107.7 101.7 78.2 89.9 82.8 76.9*

Average 106.8 101.9 79.6 88.0 82.3 75.8 NA NA NA NA

9 I 1572.5 78.6 106.5 I(10.787.3 91.3 82.1 78.5* 72.5* 68.5, 71.4* 68.3*

2 1575.078.8 104.6 100.8 86.6 91.6 86.5 71.7t 73.9* 68.0* 69.5*

3 1572.578.6 106.4 100.2 87.1 91.1 85.0 81.3 71.0,

:Average 105.9 100.6 87.0 91.3 84.9 78.7 72.6 68.5 70.0 68.9

10 ', I 1525.076.3 96.5 100.I 8%2 73.3 83.3 70.9* 74.2* 73.6*

2 1525.076.3 96.3 100.1 87.3 81.I 84.8 75.4* 74.2,

3 1525.076.3 96.4 98.0 86.9 79.5 85.6 68.2, 69.8* 74.5*

:Average 96.4 99.5 87.9 79.0 84.7 72.5 73.2 74.I NA NA

12 i I 1520.076.0 88.4 98.5 83.7 74.1 74.1 74.1* 64.5* 67.6*

I 2 1520.0 76.0 85.2 99.5 77.9 80.0 79.4 66.3* 72.0* 64.0* 62.0* 71.6*

l 3 1520.076.0 85.9 97.9 79.1 78.2 83.1 70.7* 72.2, 65.8* 61.0* 68.2*

:Average 86.7 98.7 81.0 78.I 80.2 71.4 72.1 64.8 64.6 70.2

I

17 I I 1572.5 78.6 101.2 93.2 81.4 78.I 74.5 83.0 69.9. 75.1* 68.4* 69.5.

l 2 1570.0 78.5 100.9 94.4 78.4 75.4 79.8 82.1 70.2* 70.8* 70.5* 66.5*

: 3 1570.0 78.5 100.I 90.I 81.4 79.8 68.9 76.1 72.4 71.2, 61.7, 66.2,

"- :Average lO0.B 92.9 80.6 78.1 76.4 81.3 71.0 72.8 68.2 67.7

18 I i 1522.576.1 96.5 90.7 79.1 67.2 68.1 80.6 71.5* 68.8* 72.8*

" I 2 1522.5 76.I 96.7 93.6 80.2 63.9 72.0 80.7 75.3 69.7* 63.2*

', 3 1522.5 76.1 96.3 90.7 74.0 65.8 67.0 79.2 72.1* 65._*

IAverage 96.5 91.9 78.5 65.8 69.6 80.2 73.3 69.3 NA 69.2

........... I..............

• adjustefod rBroadbandContributions NA NotAvailable

-139-
TABLE B.11

CABINMICROPHONENUMBER4 : STARBOARDENGINECOMPONENTS

........................................................................................................................

Test _ FlightI RPM :BPF ', HarmonicLevel,dBre20microPa

Condition€ Number: : Hz ; I 2 3 4 5 6 7 8 9 I0

I : I 1525.0 76.3 100.9 91.4 84.4 78,6 75.6 70.8*

: 2 1520.0 76.0 100.5 93.6 85.9 79.2 79.3 75.7*

3 1520.0 76.0 100.0 94.0 81.5 78.9 7B.0 69.3* 70.4*

:Average 100.5 93.1 84.3 78.9 77.9 73.6 70.6 NA NA NA

:

2 : I 1570.0 78.5 I01.B 91.6 82.7 75.1 78.0

2 1570.0 78.5 100.5 89.0 83.7 80.9 80.B

: 3 1572.578.6 99.1 91.3 78.4 73.8 78.I 68.0*

:Average 100.6 90.8 82.1 77.8 79.2 NA 68.0 NA NA NA

3 ', 1 1572.5 78.6 105.2 86.9 77.2 78.9 79.6 72.7 * 72.8 *

: 2 1570.078.5 105.3 BB.O 72.9 77.6 81.1 73.2* 70.3*

: 3 1570.078.5 103.2 92.6 69.4 77.6 82.6 68.4*

:Average 104.7 89.9 74.3 78.I 81.3 73.0 NA 72.B 69.5 NA

:

4 : I 1517.575.9 104.4 89.1 67.6 78.9 82.0 74.1* 72.1*

l 2 1520.076.0 104.0 90.3 76.0 73.1 80.7 70.9*

I 3 1520.076.0 103.5 90.4 76.4 79.3 82.4 73.2*

',Average 104.0 90.0 74.7 77.9 81.8 74.1 72.2 NA NA NA

,,

9 : I 1520.076.0 106.0 91.3 79.6 82.6 78.2 72.2. 76.1*

: 2 1520.076.0 104.4 90.3 B0.2 82.0 78.3 71.0. 75.4*

', 3 1520.076.0 104.3 89.7 77.1 86.0 81.0 79.3* 75.5*

:Average 105.0 90.5 79.2 83.9 79.4 75.8 75.7 HA NA NA

10 : I 1572.5 78.6 I08.0 B0.I 76.6 72.0 7B.9 82.5 71.7* 70.3*

: 2 1570.0 78.5 105.3 81.8 79.1 81.2 77.2 75.6 t 71.5. 66.2.

: 3 1572.578.6 106.7 88.I 74.3 82.5 78.I 79.2* 71.4* 67.2*

;Average 106.8 84.8 77.1 80.4 78.I 80.0 71.5 68.3 NA NA

:

11 : I 1517.5 75.9 102.6 84.3 75.5 75.9 75.6 78.0 1,9.1* 68.3* 67.2*

2 1515.075.B 102.9 86.7 74.6 77.8 78.8 78.2 69.4* &6.2* 68.4* 66.7*

3 1515.075.8 103.6 90.9 66.6 81.6 83.8 81.0 69.4. 75.1* 68.4. 67.8*

IAverage 103.1 88.2 73.6 79.1 80.7 79.3 69.4 71.7 68.4 67.3

17 : i 1517.575.9 101.0 86.4 76.6 75.6 79.2 83.1 82.0 63.1* 69.5* 69.1*

', 2 1517.5 75.9 100.2 75.6 74.1 76.1 78.3 88.3 82.6 75.0 70.1*

3 1517.5 75.9 99.2 80.5 79.7 77.7 76.7 86.3 83.1 77.0 69.0*

:Average 100.2 82.9 77.4 76.6 78.2 86.4 82.6 74.5 69.6 69.1 "

:

18 ', 1 1575.0 78.8 102.9 90.9 80.1 79.2 87.0 94.2 87.7 76.2 74.0 67.4 * "

p

: 2 1572.578.6 101.9 88.6 76.2 84.0 90.2 93.0 88.5 65.1* 75.7

I 3 1570.078.5 102.3 89.3 74.6 82.9 89.1 82.0 86.0 71.2. 71.5. 64.0.

:Average 102.4 89.7 77.6 82.5 89.0 92.0 87.5 72.9 74.1 66.0

: ..................................................................................................................

• adjuste{or d BroadbanCont d ributions NA NotAvailable

-140-
TAB LE B. 12

CABINMICROPHONENUMBER4 : PORT& STARBOARDENGINEC0MPONENTS

Test : FlightI RPM I BPF I HarmonicLevel,d8re 20 microPa

Condition',NumberI : Hz : I 2 3 4 5 6 7 8 9 I0

5 : 1 1532.5 76.6 106.3 102.1 87.3 82.1 84.7 79.2* 73.3i 71.1t

2 1530.0 76.5 102.8 101.9 87.5 80.6 85.3 74.5* 74.0* 78.5f

• : 3 1530.0 76.5 104.8 I01.8 85.0 85.5 87.2 82.9 74.3* 76.2* 70.1* 69.5*

IAverage 104.9 101.9 86.7 83.2 85.9 80.1 73.9 76.2 70.1 69.5

6 : I 1530.0 76.5 103.6 96.2 85.5 75.9 84.0 72.3t 72.9i

2 1530.0 76.5 I00.0 96.1 84.2 78.3 86.3 81.2 75.3t 74.1i 69.5t

3 1532.5 76.6 100.7 95.0 84.6 87.1 81.0 78.2J 72.6_ 74.9i 68.0i

IAverage 101.7 95.8 84.8 83.1 84.3 78.6 74.2 74.5 68.8 72.9

7 I I 1530.0 76.5 109.1 100.4 86.4 87.1 85.3 72.3_ 72.8t 70.6o 72.4i

2 1530.0 76.5 107.6 100.4 87.0 82.3 86.5 81.5 78.4i 74.7* 67.5i

Z 3 1530.0 76.5 108.2 97.6 86.2 89.6 87.5 79.1_ 75.5* 74.0i

IAverage 108.3 99.7 86.5 87.3 86.5 79.0 76.4 74.1 67.5 73.3

8 I I 1530.0 76.5 105.8 102.4 86.2 84.8 84.2 76.6t 75.9J 77.7i 70.6

l 2 1532.5 76.6 106.1 101.8 84.6 87.4 84.2 78.2t 76,9i 76.3t

3 1530.0 76.5 106.8 102.6 86.7 89.5 87.5 80._ 78.0_ 80.6i 70.5;

:Average 106.3 102.3 85.9 87.6 85.6 78.6 77.0 78.6 NA 70.6

13 ', i 1527.5 76.4 I01.9 78.8 81.4 82.9 80.1 89.2 82.4 80.1 77.2 72.9

I 2 1537.5 76.9 103.3 94.1 78.1 82.°. 81.3 92.7 86.0 79.5 77.4 67.?

3 1525.0 76.3 99.9 ,00.8 74.1 80.8 80.9 88.4 86.2 77.0 76.3 65.1i

',Average I(!1.9 91.1 78.8 82.3 80.8 90.5 85.2 79.1 77.0 69.8

14 I I 1527.5 76.4 93.6 93.5 83.2 76.2 81.9 88.1 85.0 75.0 78.3 75.2

I 2 1537.5 76.9 104.6 90.0 83.0 83.5 85.7 93.3 86.4 78.3 80,0 73.2

l 3 1527.5 76.4 88.2 89.I 82.7 79.5 85.4 84.8 86.2 75.6 77.0 72.3

IAverage 100.3 91.3 83.0 80.7 84.6 90.1 85.9 76.5 78.6 73.7

15 I I 1527.5 76.4 105.3 94.4 74.5 72.1 79.3 92.2 85.0 78.1 74.4 76.2

2 1537.5 76.9 90.9 91.5 83.3 79.0 87.2 88.3 85.7 78.2 78.9 74.6

I 3 1527.5 76.4 102.9 93.5 82.0 80.8 83.2 84.1 8b.9 75,3 76.1 71.3

:Average 102.6 93.3 81.3 78.6 84.4 89.4 85.9 77.4 76.9 74.5

I

16 : I 1527.5 76.4 101.8 91.6 79.1 79.3 80.6 89.0 84.0 75.2 77.3 74.6

l 2 1540.0 77.0 103.7 96.4 84.0 84.2 84.7 91.9 86.4 75.4 80.0 74.3

3 1527.5 76.4 102.2 90.5 79.9 81.7 81.7 84.8 84.1 76.1 77.3 72.1

". IAverage 102.6 93.6 81.6 82.2 82.7 89.5 85.0 75.6 78.4 73.8

l

• adjustedforBroadbandContributions NA NotAvailable

-141-
TAB LE B. 13

CABINMICROPHONE NUMBER5 : PORTEN61NECOMPONENTS

.... ........................ .........................

ConditionI Number: : Hz : I 2 3 4 5 6 7 B 9 10

...................................................................................................................... ,=_

1 : I 1510.079.0 99.5 104.7 93.1 11.4 73.7* 69.0* 70.9*

2 1572.578.6 98.3 103.6 94.8 85.9 78.4 78.9 a9.2* 71.7* 64.3* .

: 3 1572.578.6 I00.0 103.5 94.1 80.1 75.4 74.7* 69.4* 67.2* 70.6* "

:Average 99.3 104.0 94.3 83.2 76.3 75.8 69.9 67.2 71.2 64.3

2 ; I 1525.0 76.3 92.6 104.8 97.7 81.3 77.1* 75.8*

: 2 1525.076.3 90.6 103.4 95.6 80.9 70.5* 70.9* 66.1*

3 1525.0 76.3 93.1 103.2 92.7 80.1 72.6* 75.9* 6b.9*

:Average 92.2 103.9 95.B 80.B 74.3 74.7 66.5 NA NA NA

3 : I 1527.5 76.4 86.2 102.2 95.2 76.4 GAB B6.B 71.6*

2 1525.0 76.3 80.0 103.7 93.3 74.6 85.6 82.0 82.1 73.0*

3 1525.0 76.3 90.0 104.0 92.7 77.8 86.4 80.5 81.9

:Average 87.0 103.4 93.9 76.5 85.4 84.0 80.4 73.0 NA NA

4 : I 1572.578.6 98.8 106.8 92.8 8B.6 90.8 89.4 78.9* 76.6* 72.5*

2 1572.5 78.6 9B.I 104.4 89.6 85.3 81.8 87.9 81.5 72.7, 74.7,

3 1572.578.6 101.2 105.4 87.4 86.9 84.8 88.7 82.2* 77.7* 77.3* 73.6*

:Average 99.6 105.b 90.5 87.1 B7.4 88.7 81.I 76.1 75.3 73.6

9 I I 1572.578.6 98.2 105.9 93.6 89.1 91.6 91.0 B4.J

2 1575.078.8 93.0 105.8 90.7 88.6 90.4 86.0 80.1 72.1* 70.7*

3 1572.578.6 97.1 105.2 88.1 91.4 91.4 90.2 80.2, 67.3, 74.1*

;Average 96.6 105.6 91.4 89.9 91.2 89.5 81.9 NA 70.3 72.7

I0 : I 1525.076.3 8b.3 103.7 94.8 83.2 83.2 85.2 76.3* 74.1*

2 1525.076.3 88.8 105.2 93.0 82.5 80.3 87.9 74.7* 75.7*

3 1525.0 76.3 84.3 104.4 91.0 82.4 83.7 77.8, 75.5, 73.0,

:Average 86.9 104.5 93.2 82.7 82.6 85.3 75.5 74.4 NA HA

12 : I 1520.0 76.0 80.3 103.0 87.3 72.9 81.3 81.1 72.9, 73.7, aB.7*

2 1520.0 76.0 77.8 102.3 85.2 68.3 80.6 84.2 75.0 70.6*

: 3 1520.0 76.0 BB.4 103.4 84.3 64.3* 83.6 B2.1 77.1 72.3*

:Average 84.6 102.9 85.8 69.8 B2.0 82.7 75.3 72.4 6B.7 NA

17 I 1572.5 78.6 89.9 102.7 79.3 81.6 86.3 93.0 81.1 66.6* 80.4 69.5*

2 1570.0 7B.5 90.1 102.8 B2.3 78.4 86.9 89.1 77.0 69.B* 80.I 67.1*

3 1570.078.5 87.3 101.I 82.3 BI.O B4.4 91.0 73.2 6B.0* 76.5 i

Average 89.3 102.3 81.5 80.5 86.0 91,3 78.2 68.3 79.3 68.5

IB I 1522.5 76.1 90.1 99.2 82.1 69.4 B5.6 BB.5 79.7 66.3* D

2 1522.5 76.1 B7.5 9B.4 BI.9 76.2 16.0 B7.2 81.B 75.0 62.4*

3 1520.0 76.0 8B.9 93.5 87.9 73.6 84.1 8B.6 76.0 67.9 *

Average B9.0 97.7 84.9 73.9 85.3 BB.I 79.8 71.5 HA 62.4

• adjustedforBroadbandContributions NA NotAvailable

-142-
TABLE B. 14

CABINMICROPHONENUMBER5 : STARBOAREDNGINECOMPONENTS

.... iii....i-i iiii-i--iii--- ,-iii'-T........................ iii;ii i-iiiii -ii-;;-ii-; i;i-i; .........................

ConditionINumberI ',Hz ; I 2 3 4 5 6 7 I 9 10

I _ I 1525.076.3 94.5 97.5 81.9 72.0* 72.5*

. I 2 1520.076.0 91.B 100.5 90.3 74.0* 69.7* 69.4* 68.I * 64.2*

3 1520.076.0 95.5 98.9 81.4* 68.4* 72.6* 72.7*

IAverage 94.2 99.1 86.6 72.0 71.8 71.4 68.I NA NA 64.2

2 I I 1570.0 78.5 99.6 99.7 84.8 79.4 80.7 80.2 71.0*

2 1570.078.5 98.0 99.1 82.9 81.4 83.2 78.I 69.3* 67.4*

3 1572.5 78.6 99.1 91.7 82.2 12.2 78.5 73.7*

:Average 99.0 99.2 83.4 81.2 81.2 78.1 70.2 NA 67.4 NA

3 : I 1572.5 78.6 95.4 101.2 89.3 86.1 79.3 84.0 72.0*

2 1570.078.5 94.8 102.8 91.0 87.4 80.1 72.6* 71.1*

: 3 1570.0 78.5 95.1 103.0 90.0 86.1 74.9* 71.6* 73.4*

_Average 95.1 102.4 90.2 B6.6 78.6 79.8 72.3 NA NA NA

:

4 I I 1517.575.9 93.1 100.2 86.4 82.2 82.4

2 1520.076.0 93.8 102.1 89.0 79.4 85.4 71.3*

3 1517.575.9 92.! 100.2 89.1 79.4 83.1

:Average 93.1 100.9 88.3 80.5 83.8 71.3 HA NA NA NA

9 : I 1520.076.0 89.5 I01.6 88.0 85.2 82.6 75.5*

2 1520.076.0 91.1 101.6 88.4 83.6 85.8 78.5,

3 1520.076.0 89.4 100.4 88.5 83.3 77.5 75.3*

_Average 90.1 101.2 88.3 83.4 83.1 76.7 NA NA NA NA

:

10 : I 1572.578.6 94.9 103.4 86.7 86.3 91.3 77.9* 70.7*

2 1570.078.5 90.8 102.9 89.9 88.5 89.2 72.8* 70.1*

', 3 1572.578.6 94.9 104.4 88.5 88.6 85.9 74.1* 72.7* 67.7*

:Average 93.9 103.6 1B.6 87.9 89.3 HA 75.5 72.7 70.4 67.7

11 I I 1515.075.8 100.1 95.1 90.3 81.2 82.4 83.1 69.0, 69.3, 71.9

2 1517.575.9 98.3 98.7 89.8 81.4 83.7 82.0 65.7* 68.1* 59.6, 64.0,

3 1515.075.8 95.3 97.9 90.B 83.6 71.6 82.2 68.5, 71.5, 67.8,

:Averale 98.3 97.5 90.3 82.2 81.5 82.5 67.3 69.8 66.7 69.0

:

17 _ I 1517.575.9 93.6 96.9 84.4 83.1 83.0 89.7 63.8* 76.2 75.6* 70.6*

2 1517.575.9 93.0 93.7 86.6 83.1 84.2 88.5 75.0 73.9 71.3* 66.8*

3 1517.575.9 94.4 95.0 87.5 81.5 79.2 8&.& 71.9, 77.5, 71.6, 67.2,

:Average 93.7 95.4 86.4 82.6 82.6 81.4 72.2 76.1 73.3 68.6

_. 18 I 1575.071.8 87.7 103.3 90.9 88.7 91.3 92.7 85.1 76.3 82.3 72.4*

2 1572.5 78.6 89.1 101.3 90.7 85.4 92.6 86.2 84.0 73.9 81.0 75.2,

3 1570.0 78.5 90.2 101.7 91.3 87.8 19.5 84.0 74.3 80.7 70.6*

" Average 89.4 102.2 91.0 17.5 91.3 89.3 83.0 75.3 81.4 73.2

• adjustedforBroadbandContributions NA NotAvailable

-143-
TAB LE B. 15

CABINMICROPHONENUMBER5 : PORT& STARBOARDENGINECOMPONENTS

Test _ Flight_ RPM _BPF _ HarmonicLevel,-dB-re-20-_icro-Pa ........................

ConditioInNumber_ ; Hz ; I 2 3 4 5 6 7 B 9 10

...................................................................................................................... i

5 : I 1532.5 76.6 88.9 108.7 98.1 89.7 89.4 83.0 78.6* 77.4* 72.2* s

2 1530.076.5 91.3 108.9 97.0 88.2 89.9 83.6 78.3* 77.5* 70.6* 66.2*

; 3 1530.0 76.5 92.6 109.1 94.3 85.1 87.1 74.5* 74.7, 74.0* 71.5,

:Average 91.2 108.9 96.7 88.1 89.0 81.B 77.5 76.6 70.6 70.7 "m

6 I 1530.0 76.5 84.8 92.4 94.9 87.0 89.4 88.9 75.4* 76.4* 71.2*

2 1532.576.6 77.2 94.5 85.5 86.4 88.7 84.1 BO.l 75.7*

3 1532.5 76.6 83.9 97.1 90.6 89.9 B7.B 77.3* 73.4* 76.8* 67.8*

Average 83.0 95.1 91.9 88.1 88.7 85.6 77.2 76.3 69.8 NA

7 I 1530.0 76.5 91.8 106.0 95.2 86.4 86.7 88.1 77.9* 71.4*

2 1530.0 76.5 93.4 107.4 87.6 87.6 80.4 81.2* 78.1* 77.4* 75.3*

3 1530.0 76.5 92.8 106.0 92.4 89.4 88.2 7B.4* 74.6* 80.5* 68.4*

_Average 92.7 106.5 92.7 88.0 86.2 84.5 76.7 78.8 75.3 70.2 i

8 i I 1530.0 76.5 95.3 109.1 95.3 81.8 84.4 87.4 78.3, 69.5.

I 2 1532.5 76.6 92.6 109.1 91.4 80.4 85.2 86.0 77.1 * 75.2 *

f 3 1530.076.5 88.I I08.I 87.5 82.3 88.8 84.1 69.0* 76.7, 68.0*

;Average 92.9 108.8 92.5 81.6 86.6 86.0 74.7 76.9 NA 68.8

13 _ I 1527.5 76.4 99.4 90.1 89.7 82.4 89.0 88.4 B3.0 76.9 8!.0 69.7*

', 2 1537.5 76.9 89.4 103.5 89.9 85.6 91.8 89.2 81.1 77.0 77.9 73.2

3 1525.0 76.3 98.5 92.9 92.9 81.0 88.0 89.2 76.1 75.9 79.9 69.2*

:Average 97.4 99.3 91.1 83.4 89.9 88.9 80.9 76.6 79.8 71.1

14 l 1 1527.5 76.4 97.9 104.7 86.8 85.2 B7.0 91.2 BO.I 79.9 82.9 70.3 *

2 1537.576.9 94.6 97.1 87.4 85.6 85.9 92.3 81.2 74.7 79.3 74.8

', 3 1527.5 76.4 98.5 104.2 86.8 82.1 84.2 90.1 78.3 72.3* 78.5 71.8*

{Average 97.3 103.1 87.0 84.6 85.8 91.3 80.0 76.8 80.7 72.7

15 i I 1527.5 76.4 89.1 105.0 90.6 83.4 83.0 96.8 81.9 73.8* 79.3, 71.4*

2 1537.576.9 97.3 104.7 87.4 83.8 87.4 87.1 82.5 74.4 78.3 78.4

3 1527.576.4 90.5 102.0 87.5 85.6 89.8 90.6 81.1 76.1 78.5 72.0*

_Average 93.9 104.1 88.8 84.4 87.5 93.3 81.9 74.9 78.7 75.2

16 : 1 1527.5 76.4 98.3 98.7 89.0 84.5 89.6 93.1 82.5 79.7 81.9 71.1,

2 1540.0 77.0 88.0 102.7 87.0 86.3 93.9 92.9 81.2 74.5 79.8 76.2

; 3 1527.5 76.4 97.5 90.8 90.3 80.B 87.0 90.2 78.0 76.9 79.I 71.1*

:Average 96.4 99.6 89.0 84.4 91.1 92.3 80.9 77.5 80.4 73.5

......... ............:

-144-
TABLE B. 16

CABINMICROPHONUMBER NE 6 : PSRTENGINECSMPONENTS

........................................................................................................................

Test I FlightI RPM IBPF : HarmonicLevel,dBre20microPa

Condition: NumberI l Hz : I 2 3 4 5 6 7 8 9 10

I l I 1580.079.0 109.0 97.8 86.0 79.1 81.5 70.7*

", : 2 1572.5 78.6 107.7 99.5 84.1 78.2 84.0 72.4* 71.4f 69.7*

3 1572.578.6 108.3 97.6 87.6 82.2 83.7 68.7f 71.5J

• :Average 108.4 98.4 86.1 B0.2 83.2 70.9 71.2 NA 69.7 NA

2 1 1525.076.3 104.0 95.4 89.3 85.2 79.0i 70.0* 73.2

2 1525.076.3 102.5 96.2 BB.9 77.3* 73.5*

3 1525.076.3 103.6 93.9 83.4 83.4 74.2* 71.9* 72.8*

Average 103.4 95.3 87.9 83.0 77.2 72.0 73.0 NA NA NA

3 I 1527.5 76.4 103.1 95.4 75.0 85.0 84.3 81.3* 72.3*

2 1525.0 76.3 104.2 95.0 73.9 81.2 82.7 74.5t 77.1* 73.2*

3 1525.0 76.3 104.3 92.2 79.1 75.0* 81.7 76.1* 75.9* 70.9*

IAverage 103.9 94.4 76.6 82.0 83.0 78.3 76.5 72.2 NA NA

:

4 i I 1572.5 78.6 109.4 99.4 B4.B 87.4 93.8 81.4* 79.9* 77.5*

2 1572.5 78.6 109.2 99.5 81.1 86.9 87.9 83.1

3 1572.578.6 110.5 97.8 85.6 88.9 90.5 81.0* 74.7* 71.4.

:Average 109.7 99.0 84.2 87.8 91.4 81.9 78.0 75.4 NA NA

9 I 1572.578.6 109.8 97.2 B2.B 88.4 91.8 75.7* 75.9*

2 1575.0 78.8 107.8 98.9 85.4 B4.B 91.2 69.8* 70.6.

3 1572.5 78.6 109.4 100.6 86.9 87.9 90.2 78.5* 75.8* 73.6* 71.0*

Average 109.1 99.i 85.3 87.3 91.I 77.3 74.6 72.4 71.0 NA

10 I 1525.0 76.3 103.0 94.7 73.& 85.9 83.9 76.0* 76.6* 69.9*

2 1525.076.3 102.0 °.5.4 84.8 86.9 82.0 78.5* 74.8i

3 1525.076.3 102.2 95.5 80.I 86.5 84.4 72.4* 74.5i

:Average I(!2.4 95.2 81.5 86.5 83.5 76.3 74.7 76.6 NA 69.9

12 I 1520.076.0 100.0 82.8 72.0 85.1 87.5 84.0 78.0 76.0* 64.1*

2 1520.076.0 98.2 87.9 79.0 86.2 84.4 73.1* 70.2* 77.4.

3 1520.076.0 g8.B 86.0 80.I 85.3 83.7 76.6* 68.0* 70.3* 66.1* 61.5*

Average 99.1 86.0 78.2 85.6 85.5 80.2 74.3 75.5 66.1 63.0

17 1 1572.578.6 103.1 93.1 80.0 84.2 82.4 85.7 74.0. 78.3 73.5. 65.9*

2 1570.078.5 102.3 94.8 83.8 85.8 76.5 85.3 73.8* 75.4* 67.8* 67.5*

3 1570.078.5 101.7 92.6 82.6 82.4 83.2 81.6 77.0 71.8* 72.7*

:Average 102.4 93.6 82.4 84.4 81.5 84.5 75.2 75.9 72.0 66.8

I

• 18 l I 1522.5 76.1 96.8 91.0 72.1 * 83.°' 70.2 * 89.0. 74.8 * 72.6 * 64.4 *

2 lu_.u =_ = 76.I 97.3 91.1 76.2 85.9 73.7 88.6 79.1 74.6* 63.J" *,

- : 3 1520.076.0 96.5 91.9 82.5 80.4 78.8 85.0 77.2 68.6*

IAverage 96.9 91.4 79.0 83.o, 75.6 88.3 77.4 72.6 NA 6_.9

• adjustedforBroadbandContributions NA NotAvailable

-145-
TAB LE B. 17

CABINMICROPHONENUMBER6 :STARBOARDENGINECOMPONENTS

Test i Flight: RPM :BPF : HarmonicLevel,dBre20microPa

ConditioniNumberi _ Hz _ I 2 3 4 5 6 7 8 9 I0

I I 1525.076.3 100.5 89.1 86.5 82.3 76.1*

2 1520.076.0 99.8 91.8 70.7* 81.0 72.3* 67.4* "

3 1520.0 76.0 100.3 88.3 85.7 79.5 75.2* 68.7*

Average 100.2 90.0 84.4 81.1 74.8 67.4 68.7 NA NA NA -

2 I 1570.078.5 103.9 95.3 90.2 7B.B* 80.9* 71.0*

2 1570.078.5 102.6 93.3 87.3 78.4 73.1*

3 1572.5 78.6 102.3 96.0 BB.1 70.0* 78.5 *

Average 103.0 95.0 BB.7 77.1 78.5 71.0 NA HA NA NA

3 I 1572.578.6 103.8 92.4 80.2 74.4* 76.1* 73.9*

2 1570.078.5 104.4 94.7 74.5 76.9* 78.8* 79.0*

3 1570.078.5 101.5 99.4 76.0 80.7 75.3* 78.0*

:Average 103.4 96.5 77.6 78.I 77.0 77.5 NA NA NA NA

4 : I 1517.575.9 101.2 96.8 73.5 72.2* 80.0* 75.5* 72.6*

2 1520.076.0 101.3 96.5 77.3 75.0* 81.2

3 1517.5 75.9 100.5 95.1 78.8 76.2* 83.0 73.8* 72.9*

:Average 101.0 96.2 77.0 74.8 BI.6 74.7 72.9 NA NA 72.6

9 : I 1520.076.0 103.6 98.9 79.9 83.3

: 2 1520.0 76.0 101.B 97.B 78.5 83.5

3 1520.075.0 101.2 95.0 79.2 79.0 72.2,

:Average 102.3 97.5 79.2 82.4 72.2 NA NA NA NA NA

10 I 1572.57B.b 106.6 94.2 77.6 85.1 78.5* 75.6*

2 1570.078.5 103.6 88.1 79.5 77.6 69.7* 79.8*

3 1572.5 78.6 105.2 92.4 80.4 82.1 72,5* 80.2 * 75.7 * 74.9 *

Average 105.3 92.2 79.3 82.6 75.1 79.0 75.7 74.9 NA NA

11 I 1515.075.8 95.9 99.2 77.7 82.9 84.5 65.2* 69.I * 68.I* 68.0* 72.9*

2 1515.0 75.8 98.6 98.2 75.7 80.1 86.3 71.3, 70.6, 72.0, 65.9, 67.6,

3 1515.075.8 99.4 96.7 78.9 82.6 73.3, 68.2* 71.7, 67.4* 69.5, 67.2,

:Average 98.2 98.2 77.6 82.0 83.9 68.9 70.6 69.7 68.0 70.1

17 I 1517.575.9 95.9 93.7 81.8 66.2* 74.8 88.4 77.2 77.0 75.8* 68.6*

2 1517.575.9 95.6 93.3 84.1 72.6, 71.1* 84.9 78.8 72.9* 76.5, 67.3,

3 1517.575.9 93.4 94.2 83.9 67.6 75.3 80.7 78.5 78.6 71.5* 68.2,

Average 95.1 93.7 83.4 69.7 74.1 85.7 78.2 76.8 75.1 68.I

18 I 1575.07B.B 99.B 94.6 87.2 74.8 84.1 87.6 75.5, 79.0 70.1* 64.2*

2 1572.5 78.6 98.7 89.6 87.9 75.9 81.4 86.1 79.9 77.3 76.1 65.3*

3 1570.078.5 98.7 93.2 89.0 79.9 82.2 79.3 79.2 73.0* 70.7* 67.6* .

IAverage 99.1 92.9 88.1 77.5 82.7 85.5 78.6 77.1 73.2 65.9

• adjustedforBroadbandContributions NA NotAvailable

-146-
TABLE B. 18

CABINMICROPHONE NUMBER6 : PORT& STARBOARDENGINECOMPONENTS

.... ........................ ...............

Condition: NumbeIr : Hz : 1 2 3 4' 5 6 7 B 9 10

. 5 I 1 1532.5 76.6 104.9 99.7 82.3 86.9 85.6 78.3* 71.6 * 76.0 * 74.5* 70.4*

: 2 1530.0 76.5 102.8 99.B 80.6 85.7 85.9 84.1 73.0* 74.5* 70.4*

3 1530.0 76.5 104.6 101.5 6B.4* 86.3 82.6 79.9* 78.0* 76.2*

• IAverage 104.2 100.4 79.9 86.3 84.9 81.5 75.1 76.1 74.5 70.4

£ : I 1530.076.5 92.9 94.5 78.I 88.I 87.0 76.5* 73.0* 73.7* 76.5* 71.5*

2 1532.576.6 91.9 93.2 84.5 87.5 B2.B 75.9* 82.1 72.7* 70.0*

I 3 1532.576.6 96.0 88.7 81.I 86.7 86.5 73.3* 77.1* 74.1* 75.0*

:Average 94.0 92.7 82.0 87.5 85.8 75.4 78.9 73.5 74.6 71.5

7 : I 1530.076.5 109.7 95.9 76.2 82.0 84.8 72.5* 75.2* 73.2*

', 2 1530.076.5 108.1 9B.2 83.8 79.8 86.5 76.5* 76.0* 74.4* 73.4* 73.9*

: 3 1530.07b.5 108.9 99.4 75.3 86.1 82.7 79.8* 74.5* 79.8*

;Average 108.9 98.I 80.2 83.4 84.9 7B.5 74.6 77.2 73.3 73.9

B : I 1530.07£.5 105.7 102.2 77.3 87.7 85.9 75.0* 75.7* 73.1*

2 1530.076.5 106.1 101.4 78.8 BB.4 80.9 81.2* 72.1+ 76.3* 74.5*

I 3 1530.076.5 107.5 102.2 82.3 87.2 86.9 80.0* 77.8* 72.3*

:Average 106.5 101.9 80.0 87.8 85.2 79.4 75.8 76.0 73.4 NA

I

13 : I 1527.576.4 100.2 B6.8 BO.O BB.3 79.3 89.3 78.0 79.1 74.5* 72.3*

2 1537.5 76.9 100.4 97.6 78.5 87.8 78.7 86.2 79.0 82.1 77.3 70.2,

I 3 1525.0 76.3 9B.0 86.7 83.9 B3.2 81.8 86.0 77.1 82.2 72.1* 70.1*

:Average 99.7 93.5 81.4 87.0 80.2 87.4 78.I 81.4 75.1 71.0

:

14 : I 1527.5 76.4 90.3 98.3 80.6 83.6 78.5 90.9 79.2 81.7 75.6* 66.9*

2 1537.5 76.9 103.0 88.2 80.4 89.3 74.0 90.3 79.5 82.5 72.8* 73.0*

3 1527.5 76.4 90.0 99.4 77.B 81.7 82.3 83.1 77.1 81.3 76.1 70.5*

:Average 98.7 97.3 79.B B6.1 79.5 89.2 7B.7 81.9 75.1 70.8

:

15 : I 1527.5 76.4 102.7 97.B 83.2 83.2 75.1 92.9 82.0 71.5* 77.2 73.4*

2 1537.5 76.9 93.0 99.3 76.9 81.9 80.2 83.7 76.1 82.2 78.7 74.2

: 3 1527.5 76.4 99.3 97.8 76.6 84.3 81.9 84.3 81.0 82.2 77.1 69.7,

:Average 99.9 98.4 80.1 83.2 79.9 89.1 80.3 80.6 77.7 72.8

16 ; I 1527.576.4 100.9 94.8 83.9 85.8 79.5 92.3 BO.l 81.1 74.7* 69.8*

2 1540.077.0 100.9 98.I 78.9 BB.2 78.8 91.4 78.0 77.2 77.1 75.2

3 1527.576.4 100.1 91.0 81.6 B2.B 80.7 B4.B 79.1 79.7 76.1 7_-..9

:Average 100.6 95.5 81.9 86.1 79.7 90.5 79.2 79.6 76.1 73.0

-q ...........

• adjustedforBroadbandContributions NA NotAvailable

-147-
-148-
_- APPENDIX C

B

Interior Sound Pressure Levels at Harmonicsof PropellerBlade

Passage Frequency: Flight 4, InteriorTreated with Fiberglass.

-149-
TAB LE C. I

CABIHMICROPHOHENUHBERI : FLIGHT14

Test IFlight_ RPM IBPF _ HarmonicLevel,dBre20microPa

Condition_ Number: : Hz i I 2 3 4 5 6 7 B 9 I0

STARBOARENGINE D ."

I 4 1520.0 76.0 I01.8 94.0 89.2 69.2* 66.2*

2 1570.078.5 102.1 97.5 84.0 75.2* 69.4 "

3 1572.578.6 104.7 98.2 81.2 73.2* 73.1 72.2*

4 1517.575.9 105.3 94.1 78.4 71.0* 60.3* 73.2e 69.7*

9 1530.0 76.5 105.7 91.4 78.I 72.1* 65.0* 73.4* 67.5*

10 1572.578.6 105.0 93.2 79.8 74.8 72.8 69.7*

11 1515.0 75.8 103.1 92.4 71.7 74.2 67.4 60.0*

17 1517.5 75.9 100.7 85.3 85.8 64.3 68.I 71.4* 61.1* 59.0*

18 1572.5 78.6 101.2 92.1 83.3 78.8 66.5 79.9 60.3* 59.3* 64.3*

PORTENGINE

I 4 1575.0 7B.B 103.1 101.9 80.9 76.8 59.5,

2 1525.0 76.3 105.5 99.1 84.8 69.8* 58.9* 72.1*

3 1527.5 76.4 109.4 100.4 85.1 73.6* 64.1* 70.3,

4 1572.5 78.6 108.3 100.5 88.2 74.0. 67.9. 71.3, 64.5,

9 1575.0 78.8 108.1 101.9 B7.8 75.2 73.8 75.5, 67.1*

10 1527.5 76.4 110.7 97.5 87.6 71.6* 70.4* 74.5*

12 1520.0 76.0 109.2 93.0 77.2 65.8* 5B.4* 66.2* 57.6* 60.6*

17 1570.0 78.5 104.6 94.5 81.2 77.5 67.3 78.0* 63.7* 56.1*

18 1522.5 76.1 105.2 89.0 82.1 71.6 64.8 61.6. 62.7*

BOTHENGINES

13 _ 4 1520.076.0 106.1 92.2 84.9 73.7 69.9 77.1 64.6* 64.0* 61.4*

• adjustedforBroadbandContributions

-150-
TABLE C. 2

CABINMICROPHONENUMBER2 : FLIGHT14

....Y-iiiii-T,-'Iii-'-,T-i........................ ,i'-T iI;III I-IIIIITii-;I-ii-I III-II .........................

ConditioInNumber: : Hz : 1 2 3 4 5 6 7 8 9 I0

STARBOARDENGINE

I 4 1520.0 76.0 106.0 93.2 B0.2 78.5 62.8* 56.2* 52.3*

2 1570.0 78.5 103.3 92.5 79.6 76.5 56.8* 59.0* 51.7i

3 1572.5 78.6 106.7 96.0 73.8 72.6 73.6 65.8; 62.6 57.2* 52.1* 51.3*

4 1517.5 75.9 109.4 91.9 76.6 71.7 75.7 64.3* 59.6* 55.4*

9 1530.0 76.5 109.6 91.9 79.7 71.2 74.6 67.2* 58.6* 59.7*

10 1572.5 78.6 107.5 95.6 77.5 70.7 75.3 69.5* 58.5* 63.6 54.4*

11 1515.0 75.B 108.7 92.7 79.2 71.2 72.4 60.9, 61.3,

17 1517.5 75.9 103.9 93.4 81.8 72.1 65.9 70.0 67.8 54.5* 59.0* 53.2

18 1572.5 78.6 102.1 95.2 73.9 77.6 70.7 75.4 63.8 56.4* 57.0* 55.2

PORTENBINE

I 4 1575.0 7B.B 105.1 103.0 81.2 71.0 68.9 68.6 59.0* 52.7*

2 1525.0 76.3 108.7 101.4 79.7 69.1 67.1 53.5* 53.5*

3 1527.5 76.4 112.0 94.1 79.5 69.2 76.2 73.1 b3.3

4 1572.5 78.6 109.4 99.4 82.2 67.B 77.9 71.3 65.2

9 !575.0 78.8 109.1 97.0 79.2 61.0, 79.0 76.2 69.0 51.0, 58.9* 54.9.

10 1527.5 76.4 112.7 94.6 86.6 68.7 75.7 77.6 65.3 53.0* 53.8*

12 1520.0 76.0 111.0 96.0 86.0 66.7 61.2 72.5 62.0 55.3

17 1570.0 78.5 105.9 97.3 83.3 71.0 76.3 71.1 61.1 63.0 60.9

IB 1522.576.1 107.2 94.5 81.8 66.4 6B.B 73.7 67.8 62.3 55.9

BOTHENGINES

13 : 4 1520.076.0 108.4 96.8 85.1 72.6 69.9 74.3 67.B 61.2 63.6 57.0

* adjustedforBroadbandContributions

-151-
TABLE C.3

CABINMICROPHONE NUMBER3 : FLIGHT#4

........................................................................................................................

Test :Flight: RPM : BPF : HarmoniLcevel,dBre20microPa

Condition: Number: : Hz : 1 2 3 4 5 6 7 8 9 10

STARBOAERNDGINE

I 4 1520.0 76.0 91.2 92.9 93.2 70.4 73.1 58.2* 59.3* 53.0

2 1570.0 78.5 84.2 BG.B 93.B 77.0 69.6 60.7* 54.3 55.3* "

3 1572.5 78.6 79.5 91.5 90.4 83.5 81.1 74.0 64.3, 61.5 58.6,

4 1517.575.9 97.2 92.8 89.6 81.4 78.9 65.6* 63.7* 5B.I

9 1530.0 76.5 98.9 94.7 90.7 82.6 76.2 75.0 68.6 56.2 54.9*

10 1572.578.6 91.4 87.6 90.4 81.7 7B.9 75.0 6B.I 63.4 62.1*

11 1515.0 75.8 97.6 93.7 88.5 81.9 72.9 73.1 61.2 bO.1 56.3, 52.7,

17 1517.5 75.9 97.3 92.7 82.8 78.3 69.6 83.2 59.7* 61.5 59.5* 63.6

18 1572.578.6 89.9 90.4 80.3 79.B 74.8 87.6 67.5 73.1 70.1 64.4

PORTENGINE

I 4 1575.07B.B I07.B 99.1 86.1 72.B 66.6 67.1 57.3, 54.7, 54.0

2 1525.076.3 106.5 93.9 84.4 69.1 69.7 66.9 55.6* 51.2*

3 1527.576.4 105.4 86.1 85.2 81.9 75.4 72.5

4 1572.578.6 !07.! %.4 89.9 81.5 79.6 76.4 59.3* 59.7, 57.3,

9 1575.07B.B 105.0 90.7 Bb.9 83.1 80.2 7B.6 62.7, 60.0, 61.6, 52.5,

10 1527.576.4 102.9 91.5 8B.2 83.B 69.9 71.9 61.1* 58.0,

12 1520.076.0 104.3 94.8 B3.9 79.0 72.3 70.0 62.7 5B.2 52.5* 48.5*

17 1570.07B.5 95.7 93.6 84.5 78.9 68.2 70.2 68.9 59.8 46.5* 51.2*

18 1522.57b.I 92.0 93.4 83.3 76.3 75.7 72.9 6B.0 53.5* 58.I* 50.0*

BOTHEN61NES

13 : 4 1520.076.0 98.4 96.7 85.3 80.4 76.4 84.3 67.1 63.7 _3.2 _2.1

:

* adjustedforBroadbandContributions

-152-
TABLE C.4

CABIN MICRDPHONE NUMBER 4 : FLIGHT 14

Test : Flight: RPM : BF'F :

: Condi tion : NUlllber : : Hz : 2 3

Harmonic Level, dB re 20 licro Pa

45678 9 11) 1 ______________________________________________________________________________________________________________________ :

STARBOARD ENGINE .

- ---------------- 1 4 1520.0 76.0 104.4 84.4 79.4 72.1 66.9 60.3 • 59.6 • 60.3 •

2 1570.0 78.5 100.1 75.8 81.6 66.1 58.0 • 55.3 •

3 1572.5 78.6 105.6 78.9 78.7 71.3 67.9

4 1517.5 75.9 109.8 88.6 72.6 65.2 75.9 63.7 • 60.7 f 61. 3 •

9 1530.0 76.5 110.4 84.8 77.5 70.9 70.1 66.6 • 62.8 f 61. 9 •

10 1572.5 78.6 106.7 83.5 79.8 70.5 69.5 61. 9 f 65.2 • 60.0 f 55.5 f

11 1515.0 75.8 109.2 86.1 73.0 67.5 73.7 63.3 f 57.2 • 62.7 54.9 • 54.7 * 17 1517.5 75.9 106.6 82.7 65.7 64.2 71.8 69.8 60.2 • 52.0 * 18 1572.5 78.6 102.0 89.0 65.7 71.3 75.2 71.1 68.2 59.1 • 59.1 f 49.4 *

PORT ENGWE

----------- 1 4 1575.0 78.8 111. 3 93.0 81.3 77.7 68.1 62.6 • 53.4 f

2 1525.0 76.3 111.6 94.3 78.2 72.9 58.4 • 59.6 •

3 1527.5 76.4 112.6 1M , ? 78.1 80.1 60. (, •

4 1572.5 78.6 113.0 99.6 80.4 81.9 65.6 f 68.4 f 57.3 *

9 1575.l- 78.8 I! 1.1 99.9 75.4 81.5 57.8 f 68.3 f 60.1 f 57. (, * 10 1527.5 76.4 111. 7 98.9 76.9 78.9 71.8 69.2 66.9 f

12 1520.0 76.0 111.2 96.8 57.5 71.5 72.0 64.1 61.6 61.7 49.6 f

17 1570.0 78.5 104.4 93.b 76.7 70.1 7(i.4 64.1 55.1 f 51. 0 f 53.5 *

18 1522.5 76.1 104.0 92.0 75.6 70.2 68.8 64.2 57.5 f 54.7 f

BOTH ENGINES

13 4 1520.0 76.0 107.8 92.4 75.1 68.7 73.2 72.6 61.2 58.1 f 61.4 52.6 t

f adjusted for Broadband Contributions

-153-
TABLE C. 5

CABINMICROPHONENUMBER5 : FLIGHT#4

........................................................................................................................

Test IFlight: RPM ',BPF I HarmonicLevel,dBre20microPa

ConditionI Number: I Hz I I 2 3 4 5 6 7 B 9 10

STARBOARDENGINE

I 4 1520.0 76.0 107.4 B9.B 77.6 63.4* 57.2* 57.5i

2 1570.0 78.5 106.0 90.6 78.5 59.8* 59.0* 58.0* 60.3* -

3 1572.5 78.6 I08.8 91.8 69.6 64.2* 59.0* 64.8* 59.6*

4 1517.5 75.9 110.8 93.5 74.9 68.0 72.2 59.3* 58.3;

9 1530.0 76.5 111.3 95.5 76.7 57.0* 73.8 67.4* 60.7; 59.4*

I0 1572.5 78.6 109.0 89.7 78.9 66.5* 73.1 68.5* 62.5*

II 1515.0 75.8 109.5 96.3 79.2 73.2 67.3 65.3 62.2 62.5 54.2*

17 1517.5 75.9 106.6 95.4 79.9 61.5* 67.4 55.1* 64.1 56.9*

IB 1572.578.6 103.9 94.6 BO.O 70.4 71.5 70.6 65.1 65.5 56.1* 57.4*

PORTENGINE

I 4 1575.0 78.8 106.2 100.6 87.2 77.7 70.6 61.1* 54.4,

2 1525.0 76.3 109.1 98.5 84.9 76.6 63.2m 53.8*

3 1527.5 76.4 111.9 100.0 70.7 80.4 79.5 66.2, 60.6, 58.6,

4 1572.5 78.6 llO.B 100.3 78.6 81.5 84.1 61.!* 61.4. 62.4*

9 1575.0 78.8 109.3 101.5 77.0 83.4 86.4 70.4* 64.4. 65.3

10 1527.5 76.4 111.7 100.4 80.9 83.0 79.1 69.9 59.9* 56.9*

12 !520.0 76.0 110.7 97.0 79.2 74.2 76.6 72.1 60.2 55.3, 59.8 54.8*

17 1570.0 78.5 104.1 93.7 78.6 82.6 77.8 72.2 63.1 63.1 57.2* 50.3*

18 1522.5 76.1 I05.0 91.4 79.2 81.7 75.5 67.8 55.2* 61.0, 50.7*

BOTHENGINES

13 I 4 1520.0 76.0 108.4 96.9 82.1 80.2 76.1 68.2 62.8 61.0 59.4 52.9

* adjustedforBroadbandContributions

-154-
TABLE C. 6

CABINMICROPHONNUMBER E 6 :FLIGHT14

.... --"........................ ................

Condition_Humber_ _ Hz _ I 2 3 4 5 6 7 B 9 10

STARBOARDENGINE

I 4 1520.0 76.0 98.5 96.4 76.5 69.8 60.1* 61.2* 56.B* 53.3

2 1570.0 78.5 100.1 96.2 82.4 72.9 57.0* 66.2 56.2* 53.5

3 1572.5 78.6 100.5 101.2 81.7 75.2 75.5 68.6 64.0* 55.8 58.6 52.2*

4 1517.5 75.9 98.9 98.0 79.3 75.7 74.6 68.7 60.1* 55.1 54.5*

9 1530.0 76.5 98.9 100.5 78.I 79.2 77.2 73.4 64.4* 61.5

10 1572.5 78.6 98.6 101.2 80.4 79.5 81.2 74.2 67.7 59.9 56.9*

II 1515.0 75.8 96.1 97.9 81.9 74.5 70.2 72.0 52.9* 60.6 58.2 52.5*

17 1517.5 75.9 94.2 95.6 80.7 78.5 78.3 77.9 54.5* 69.7

18 1572.578.6 95.9 97.5 83.0 77.6 79.0 82.1 69.0 66.1 60.8 56.7

PORTENGINE

1 4 1575.07B.B 97.4 106.1 97.5 BB.7 6b.9, 71.2, 57.8, 51.2, 62.0

2 1525.076.3 97.4 105.2 97.0 86.0 66.2* 72.6 52.8* 51.8*

3 1527.576.4 99.b 105.5 93.b 84.3 B4.B 77.1 66.7 57.7*

4 1572.57B.b 99.B 10b.B 9_.B 90.2 87.9 82.3 bB.7 b5.5 64.1 52.4*

9 1575.078.8 97.7 107.4 9i.5 89.1 87.9 84.1 69.1 65.& 66.0 53.9*

10 1527.576.4 98.3 105.9 90.9 84.9 83.5 80.! 71.2 64.B* 54.0*

12 1520.0 7b.O 99.4 104.2 87.1 84.0 80.1 78.9 65.2 55.7* 50.3* 51.1*

17 1570.078.5 89.7 I02.B 88.2 85.B 84.5 73.4 a5.2 61.9 63.1 58.I

18 1522.576.1 90.3 101.2 BB.3 80.5 81.4 75.5 70.1 53.0* 57.4

BOTHENOINES

13 : 4 1520.0 76.0 97.6 102.1 89.1 81.6 82.1 B0.5 69.2 &6.2 63.0 59.4

I

* adjustedforBroadbandContributions

-155-
-156-
: APPENDIX D

One-ThirdOctave Band Spectra for Exterior FluctuatingPressures:

Flights 3 and 4.

-157-
TABLE D. 1

ONE-THIRDOCTAVBAENDSOUNDPRESSURLEVE ELSFL, IGHT13

EXTERIOMICR ROPHOPNOERT,SIDE.

Band One-ThirdOctaveBandSoundPressureLevel, dBre 20microPa :

Center ..................................................................................

Frequency TestCondition : "

Hz 1 2 3 4 5 6 7 B 9 :

25 100.5 99.5 97.3 9B.3 96.8 97.0 96.5 96.5 96.0

32 101.3 101.3 9B.5 9B.3 97.0 97.B 97.3 97.3 98.3

40 103.0 103.3 lO0.B IOl.O 99.5 99.B 99.5 99.8 I00.0

50 107.0 106.5 104.5 105.0 103.0 103.0 103.B 103.3 103.8

63 113.0 115.5 114.8 112.5 114.8 114.0 115.0 115.3 111.8

80 129.B 129.5 129.0 129.5 129.3 129.0 129.5 130.0 129.0

100 113.3 111.5 109.8 112.3 109.5 110.0 110.0 110.0 111,8

125 114.5 I15.8 114.0 112.8 113.B 115.3 113.8 114.5 112.5

160 129.8 12B.8 127.B 129,0 127.5 129.3 127.5 128,B 129.0

200 117.8 119.5 118.0 117.0 117.3 118.5 118.5 118.8 116.5

250 127.0 125.3 123,5 126.0 123.8 124.8 124.8 125.3 126.3

315 123.0 121.8 120.0 122.0 120.0 121.0 121.5 121.0 123.0

400 120.0 118.5 116.5 118.5 117.0 118.5 118,0 117.5 1113

500 119.0 117.5 115.3 118.0 115.8 116.5 11b.5 116.3 118.3

630 116.0 115.3 113.0 114.5 113.0 113.5 113.3 113.3 114.5

800 ]15.3 115.3 112.8 113.8 III.8 113.0 113.0 112.5 113.3

1000 115.0 115.3 113.0 113.3 112.3 112.5 112.5 112.5 112,3

1250 114.5 114.8 112.5 113,0 112.0 112.3 112.0 112.3 112.3

IbO0 114.5 114.5 112.5 113.3 111.5 112.0 111.5 112.0 111.8

2000 114.3 114.0 112.3 113.3 111.5 111.5 111.5 111.8 112.0

2500 113.5 113.8 111,B 112.5 110.8 111.3 111.0 111.0 111.3

3150 113.3 113.5 111.8 112.B 111.3 111.8 111.8 111.0 112.0

4000 113.0 113.0 111.8 112.B 111.0 111.5 111.3 111,5 111.8

5000 111.8 112.0 111.3 111.5 110,5 111.3 110.5 110.5 110.8

NA NotAvailable

-158-
TABLE Dol (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT#3

EXTERIORMICROPHONE, PORTSIDE.

.................................................... _ ..........................................

Band One-ThirdOctaveBandSoundPressurLe vel,dBre20microPa

: Center ......................................................................

Frequency TestCondition

Hz I0 II 12 13 14 15 16 17 IB

25 96.3 91.B 93.5 93.0 93,3 93.5 92,B 92.B 93.5

9 7 € 32 97.0 93.0 93.3 93.3 9_.o 92.B 93.3 93.5 9o.,_

40 99.8 96.0 95.B 94.8 95.0 94.3 94.8 94.8 95.3

50 103.3 97.8 99.8 97.5 9B.0 98.0 98.0 98.3 98.3

63 115.0 IOl.O 113.8 111.3 II0.3 109.3 111.3 107.5 110.5

BO 129.3 109.8 127.5 19= •.J.J= 124.5 123.3 125.8 124.5 124.5

100 109.8 102.0 107.0 105.0 104.8 104.3 105.8 106.8 104.8

125 114.3 104.5 111.5 109.8 108.5 110.3 110.3 107.3 109.8

160 128.3 109.5 125.3 124.0 121.8 124.3 124.0 124.0 123.3

200 118.5 104.8 115.0 114.3 114.0 114.0 113.5 112.8 115.0

250 124.5 105.8 120.0 120.5 120.0 120.3 120.3 122.8 120.5

315 120.S 106.5 116.8 115.5 117.3 118.3 116.3 118.8 117.3

400 1!7.5 I%.B I13.0 113.3 115,0 115.0 114.8 116.0 I14.B

500 116.3 108.0 109.5 111.8 113.0 113.B 113.5 114.5 I12.8

630 113.3 107.8 107.8 109.3 !09.8 110.5 109.8 111.5 109.3

B'>O !12.3 !08.3 lOB._ lOB.O 109.0 109.3 lOB.B 110.3 108.5

1000 112.5 !08.5 lOB.O 108.0 108,5 108.5 108.5 109.4 I08.0

1250 111.5 I('B.B 108.3 107.8 108.0 108.5 lOB.O 108.5 108.3

IbO0 112.0 109.3 I07.B I07.B 108.3 I08.5 IOB.O 108.0 I08.5

2000 !!1.5 IOB.3 107.8 107.3 IOB.O 108.5 I08.0 107.5 I08.0

2500 111,0 108.3 107.5 107.3 107.5 I08.0 107.3 107.5 107.5

3150 110.5 IOB.3 107.8 107.5 I07.B 107.8 107.5 107.5 107.8

4000 1!0.5 I08.0 107.3 107.0 107.3 107.3 107.5 106,8 107.5

5000 110.8 107.5 106.0 106.8 107.3 107.0 107.3 106.5 107.3

..................................................................................

NA NotAvailable

-159-
TABLE D. 2

ONE-THIRODCTAVBAE NDSOUNPRD ESSURE LEVELSFL, ISHT13

EXTERIORMICROPHONE T STARBOARDSIDE.

Band One-ThirdOctaveBandSoundPressureLevelT dBre 20 microPa J Center ...................................................................................

Frequency TestCondition

Hz t 2 3 4 5 6 7 B 9

25 107.0 I07.B 102.0 tOI.B 100.0 I01.3 i01.5 101,5 101.0

32 106.5 I08.3 102.0 I01.B IO0.B 101,5 102.3 I01.3 IOI.B

40 109.0 IOB.B 103,3 104.3 102.5 103.0 103.0 I02.B 103.5

50 110.0 II0.B 105.3 105.0 104.5 104.5 104.8 104.5 105.0

63 116.8 114.5 112.0 115.3 112.8 113.0 114.5 113.3 114.0

BO 129.3 129.0 128,0 128,3 127,0 127.3 129.0 127.3 127.5

I00 114.0 115.3 112.3 111.0 109.8 110.3 110.8 110.5 110.3

125 116.3 115.3 112.3 114.5 113.5 112.5 113.5 113.3 113.5

160 126.5 126.5 126.0 126.0 126.5 125.0 126.0 126.0 125.5

200 118.3 117.5 114.5 116.0 115.3 115.B 115.5 115.8 116.0

250 122.0 122,5 121.8 120,5 121.3 120.8 121.5 121.5 120.5

315 118.8 119.3 118.8 118.5 119.0 119.0 118.3 118.5 118.5

400 118.5 119.3 116.B 116.8 116.0 117.0 116.3 116.5 116.3

500 119.0 120.3 116.3 116.3 115.0 116.0 115.8 115.5 115.0

630 119.3 120.0 115.3 I15.B 114.0 114.5 114.3 114.0 114.5

800 119.5 120.5 115.5 116.0 113.8 114.8 114.8 114.3 114.8

I000 120.0 121.0 115.5 116.3 114.0 114,5 114.8 114.8 114.5

1250 I19.8 120,3 115.3 116.0 113,8 114.5 114.5 114.5 114.0

1600 119.8 119.8 115.5 115.B 113.5 114.3 114.3 114.3 114.0

2000 119.0 119.B 115.5 115.5 113.3 113.5 114.0 114.0 113,8

2500 118.0 118.3 114.0 114.8 112.5 113.3 113.5 113.5 113.3

3150 117.5 117.8 I14.0 114.5 112,0 113.0 113.3 113.3 112.5

4000 115.B 116.3 113.3 113.8 111.3 113.0 112.3 112.3 112.0

5000 113.5 115.0 111.5 112.3 109.8 111.0 110.8 111.3 111.0

..................................................................................

NA NotAvailable

I

-160-
TABLE D.2 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT13

EXTERIORMICROPHDNE, STARBOARDSIDE.

Band One-ThirdOctaveBandSoundPressureLevel,dBre20microPa

Center .......................................................................

Frequency TestCondition

Hz 10 11 12 13 14 15 16 17 18

25 101.8 97.8 94.8 96.3 95.5 96.8 96.5 95.5 96.3

32 102.0 98.3 97.3 %.8 97.3 97.3 %.0 97.0 97.8

40 102.8 110.3 9%3 98.5 98.5 9B.B 99.0 98.3 98.8

50 104.5 102.0 100.8 100.5 101.0 100.8 101.0 100.5 100.3

63 111.3 114.8 102.8 111.8 110,5 111.0 111.8 111.3 108.5

80 128.0 128.0 110.8 125.B 124.5 125.0 125.8 125.0 125.3

100 112.3 108.0 105.3 106.8 I06.8 I06.B 107,0 106.3 108.5

125 !12.3 112.B 106.B ltO.B 111.0 110,B 111,0 11!,5 109.0

160 126.3 125.3 I08.0 124.3 125.0 124.0 124.8 124.3 125.3

200 114.5 115.8 106.8 115.0 114.5 114.5 115.0 115.3 113.3

250 122.3 120.8 106.5 121.0 121.3 121.0 121.0 120.3 122.0

315 119.3 116.8 107.3 119.0 1110 118.8 118.8 118.3 120.3

400 1!7.0 113.3 108.0 116.B 116.5 117.0 117.3 116.0 118.8

500 116.5 110.8 I08.5 114.5 115.0 115.0 114.8 113.5 117.5

630 114.3 109.8 108.0 110.5 110.5 111.0 111.0 109.8 113.0

BOO 115.0 109.3 108.5 108.5 108.5 I08.8 IOS.3 108.5 111.0

1000 114.8 109.5 109.0 107.5 108.3 I08,5 108.3 107.5 109.0

1250 114.0 108.8 108.5 107.3 107.5 107.3 107.3 107.3 108.0

1600 114.3 109.0 109.0 107.0 107.8 107.0 107.3 107.0 107.8

2000 113.B 108.8 108.5 106.8 107.0 107.0 107.3 107.5 IOB.3

2500 113.3 I07.B 108.5 106.3 106.8 106.8 106.8 106.5 107.3

3150 112.5 107.8 108,0 106.5 106.8 106.5 106.5 106.8 106.8

4000 111.5 107.0 IOB.0 106.3 106.3 106.8 I06.3 106.0 105.5

5000 110.5 105.8 106.8 105.0 105.3 105.3 I05.0 104.5 105.3

NA NotAvailable

-161-
TABLE D. 3

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELSFLIG , HT#4

EXTERIORMICROPHONE, PORTSIDE.

Band One-ThirdOctaveBandSoundPressureLevel, dBre 20 microPa

Center .......................................................................:

Frequency TestCondition

Hz I 2 3 4 5 6 7 8 9

25 104.8 104.3 I02.0 102.5 NA NA NA NA 100.5

32 106.0 104.8 101.5 102.3 NA NA NA NA 100.8

40 107.3 107.3 104.0 103.8 NA NA NA NA 102.5

50 111.0 111.0 108.5 108.5 NA NA NA NA I07.0

63 117.0 120.3 118.5 115.3 NA NA NA NA 114.0

80 134.3 134.3 132.5 132.5 NA NA NA NA 131.8

100 117.5 116.0 113.8 115.3 NA NA NA NA 114.0

125 118.5 120.5 118.0 116.0 NA NA NA NA 114.8

160 134.0 133.5 132.0 132.0 NA NA NA NA 131.8

200 122.3 124.0 122.0 120.0 NA NA NA NA 119.5

250 131.3 129.8 128.3 129.5 NA NA NA NA 129.0

315 127.3 126.0 124.3 125.3 NA NA NA NA 125.3

400 124.3 123.0 120.8 122.0 NA NA NA NA 122.0

500 123.5 122.3 119.8 121.3 NA NA NA NA 120.8

630 120.0 119.5 117.3 118.0 NA NA NA NA 117.0

BOO 119.8 IIB.8 I16.B 117.0 NA NA NA NA 116.0

1000 119.0 119.5 116.8 116.8 NA NA NA NA 115.3

1250 118.8 119.0 116.3 115.8 NA NA NA NA 114.5

1600 118.8 lIB.B 116.0 116.0 NA NA NA NA 114.5

2000 118.5 118.8 116.0 115.8 NA NA NA NA 1!4.5

2500 118.0 118.0 115.5 115.8 NA NA NA NA 114.0

9qC_ o,u, 117.5 117.3 115.5 115.B NA NA NA NA 114,0

4000 117.5 117.0 115.8 115.5 NA NA NA NA 114.0

5000 116.5 115.8 114.3 114.5 NA NA NA NA 113.0

NA NotAvailable

-162-
TABLE D.3 (CONTINUED)

ONE-THIROCD TAVBEANDSOUNPDRESSURE LEVELS. FLIGH14T

EXTERIORMICROPHONE, PORTSIDE.

Band One-ThirdOctaveBandSoundPressurLeevel,dBre20microPa

Center .......................................................................

Frequency TestCondition

Hz I0 II 12 13 14 15 16 17 18

25 I00.8 94.0 95.8 93.8 NA NA NA 94.8 95.0

32 100.3 96.3 96.3 95.0 NA NA NA 95.0 94.5

40 102.8 98.8 99.0 96.5 NA NA NA 96.5 96.8

50 106.8 I00.0 102.3 I00.0 NA NA NA I01.0 100.8

63 118.0 102.8 115.5 I12.B NA NA NA 109.5 112.5

80 132.0 111.3 129.5 126.3 NA NA NA 126.5 126.5

I00 112.3 105.3 109.3 106.5 NA NA NA 109.0 106.8

125 117.5 I07.0 114.0 112.0 NA NA NA 110.5 112.5

160 131.3 112.3 127.5 125.5 NA NA NA 127.0 126.0

200 122.0 107.8 117.3 116.8 NA NA NA 115.5 117.8

250 128.0 109.0 123.0 122.3 NA NA NA 125.8 123.5

315 124.0 108.8 119.3 118.3 NA NA NA 121.5 119.5

400 121.5 109.8 115.0 116.0 NA NA NA 119.0 117.5

5c30 120.0 110.5 11_.0 _ = 114.0 NA NA NA 118.3 115.5

630 116.8 110.5 109.8 III.0 NA NA NA 114.5 112.3

800 116.0 11!.5 110.3 110.5 NA HA - NA 113.3 110.5

I000 115.3 I11.8 111.0 110.3 NA NA NA III.0 110.5

1250 114.3 112.0 110.3 109.8 NA NA NA 111.0 110.8

1600 114.8 112.0 110.8 10%8 NA HA HA 110.5 110.5

2000 114.5 111.5 110.3 10%8 NA NA NA 110.5 110.3

2500 114,0 111.5 109.8 109.5 NA NA NA 110.3 110.5

3150 114.5 111.5 109.8 109,5 NA NA NA 110.3 110,3

4000 114.3 I!I.0 10%8 109.8 NA NA NA 110.5 II0.0

5000 113.8 110.3 10%0 108.8 NA NA NA 109.5 109.3

NA NotAvailable

-163-
TABLE D. q

ONE-THIRDOCTAVBAND E SOUNDPRESSURLEVELS. E FLIBHT14

EXTERIORMICROPHONE, STARBOARDBIDE.

Band One-ThirdOctaveBandBoundPressurLe vel,dBre20|icroPa

Center .......................................................................

Frequency Test Condition

Hz 1 2 3 4 5 6 7 B 9

t

25 107.0 107.5 102,8 102.0 NA NA NA NA I00.0

32 I07,0 108.5 I01,3 101.8 NA NA NA NA I00.0

40 108.5 109.8 104.0 103.5 NA NA NA NA 101.8

50 109.3 111.0 I05,3 I05.B NA NA NA NA 103.5

63 117.0 114.5 112.3 115.3 NA NA NA NA 113.8

80 130.0 129.3 128.8 128.8 NA NA NA NA 127.8

100 114.5 115.8 112.5 110.B NA NA NA NA 109.8

125 116.5 116.0 112.8 114.3 NA NA NA NA 112.8

160 127.0 127.0 127.0 126.0 NA NA NA NA 125.8

200 118.5 117.5 115.0 116.5 NA NA NA NA 115.8

250 121.5 122.5 122.5 120.8 NA NA NA NA 121.5

315 119.5 119.B 119.3 118.3 NA NA NA NA 118.5

400 118.5 119.5 117.3 116.5 NA NA NA NA 116.3

500 119.0 120.5 116.8 116.0 NA NA NA NA 115.0

630 119.0 120.5 115.8 115.5 NA NA NA NA 114.0

B00 119.0 121.3 115.5 115.5 NA NA NA NA 113.8

1000 119.5 121.3 115.8 115.8 NA NA NA NA 114.0

1250 119.0 120.8 116.0 115.5 NA NA NA NA 113.5

1600 118.5 120.5 115.8 114.8 NA NA NA NA 113.5

2000 118.5 119.B 115.B 115.0 NA NA NA NA 113.3

2500 117.8 119.0 I15.0 114.B NA NA NA NA 112.5

3150 116.8 11B.5 113.5 114.5 NA NA NA NA 112.3

4000 115.8 116.3 113.0 113.3 NA NA NA NA 111.0

5000 113.8 115.B 112.0 111.0 NA NA NA NA 109.8

NA NotAvailable

-164-
TABLE D.4 [CONTINUED]

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELSFLI . GHT14

EXTERIORMICROPHONE, STARBOARDSIDE.

Band 0ne-ThirdOctaveBandSoundPressureLevel, dBre 20 microPa

: Center .......................................................................

Frequency TestCondition

Hz I0 11 12 13 14 15 16 17 IB

.................................................................................. i

25 I01.0 97.B 93.0 95.3 NA NA NA 93.B 94.B

32 101.3 97,3 95.3 94.8 NA NA NA 95.3 94.8

40 103.0 9B,5 97.0 96.5 NA NA NA 97.0 97.0

50 104.3 101.5 99.B 9B.B NA NA NA 9B.B 99.0

63 111.3 115.0 102.3 112.3 NA NA NA 111.5 109.3

BO 128.0 128.5 I11.0 125.8 NA NA NA 125.0 125.3

I00 111.5 IOB.5 104.3 106.0 NA NA NA 105.3 108.0

125 111.8 113.0 106.3 111.3 NA NA NA 110.8 108.3

160 126.8 125.5 107.3 124.5 NA NA NA 124.0 125.0

200 114.8 116.5 105.8 116.0 NA NA NA 115.3 112.5

250 123.0 121.0 106.0 121.0 NA NA NA 120.3 122.5

315 119.8 117.0 106.5 118.5 NA NA NA 118.0 120.0

400 117.5 113.B 106.8 115.B NA NA NA 115.8 118.0

500 116.5 111.0 108.0 113.5 NA NA NA 113.8 117.0

630 114.5 110.5 107.8 !!0.3 NA NA NA I09.B 112.5

BOO 115.0 107.8 108.5 107.3 NA NA NA I07.B 1!0.5

1000 114.3 110.3 IOV.O 107.5 NA NA NA I07.B 108.5

1250 114.8 109.3 109.3 106.8 NA NA NA 106.8 107.8

1600 114.0 109.8 tOB.B 106.8 NA NA NA I05.B 107.5

2000 113.8 IOB.B 109.S 106.3 NA NA NA 106.8 107.3

2500 113.3 lOB.5 I08.B 106.8 NA NA NA 106.8 I07,0

3150 112.3 108.5 10S.B 106.3 NA NA NA 106.3 106.5

4000 112.0 IOB.O 107.8 106.0 NA NA NA 106.0 106.5

5000 111.3 I05.B 106.8 105.0 NA NA NA 104.8 105.0

NA NotAvailable

-165-
-166-
: APPENDIX E

One-ThirdOctave Band Spectra for InteriorSound Pressures:

Flight 3, Bare Interior.

-167-
TABLE E. I

ONE-THIROCTD AVEBANDSOUNDPRESSURLE VELSFLIG . HT13

CABINMICROPHONUNEMBERI

Band One-ThirOcd taveBandSoundPressureLevel, dBre 20 microPa ] Center ..............................................................................

Frequency TestCondition

Hz I 2 3 4 5 6 7 8 9 "

..................................................................................

25 84.5 84.3 B7.3 86.0 90.3 90.0 88.8 87.0 89.0

32 85.0 85.0 78.3 80.3 80.0 80.5 80.0 79.8 82.0

40 74.8 75.3 69.0 69.5 68.5 68.3 69.0 69.3 69.5

50 78.0 77.8 77.0 77.8 77.0 74.5 79.0 78.0 78.0

63 94.3 96.0 96.8 96.3 96.5 92.3 98.5 97.8 95.8

80 111.5 110.8 111.5 113.8 111.3 107.0 113.3 112.3 113.8

100 92.5 89.8 90.8 94.3 90.3 86.8 91.5 91.0 94.5

125 85.8 84.0 84.5 86.8 83.8 86.8 84.5 85.8 85.3

160 97.3 95.0 95.5 96.5 92.5 98.5 92.8 96.0 95.3

200 92.5 89.3 87.0 88.5 87.8 89.0 89.3 89.8 89.0

250 97.3 93.8 91.5 92.0 88.5 92.5 93.3 93.3 91.8

315 90.0 89.0 93.0 94.5 87.8 93.3 92.5 89.3 92.5

400 84.5 85.0 87.0 87.5 86.5 88.0 87.8 87.3 86.8

500 87.5 87.5 89.0 90.3 91.0 91.5 91.0 90.0 90.8

630 86.8 86.8 87.8 87.3 86.8 86.8 87.3 87.3 87.5

800 85.0 84.8 85.0 85.3 85.0 85.5 85.5 85.3 85.5

I000 85.5 84.5 84.5 86.5 85.5 86.3 86.0 86.0 86.3

1250 84.8 84.8 82.3 83.5 82.3 83.5 83.8 83.8 83.8

1600 82.5 82.8 81.0 81.3 79.8 81.3 81.8 81.0 81.0

2000 79.5 7B.8 79.0 79.8 78.8 80.0 80.8 79.8 80.5

2500 76.5 76.0 77,0 77.8 75.8 77.8 77.8 77.0 77.3

3150 72.3 71.5 73.8 74.8 73.5 74.8 75.8 74.3 74.8

4000 70.5 70,0 72.3 73.0 70.8 72.0 73.3 71.5 72.5

5000 67.5 67.0 69.8 70.3 b8.O 70.0 71.3 69.8 70.3

NA NotAvailable

-168-
TABLE E,1 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNPDRESSURE LEVELS. FLIGHT13

CABINMICROPHONENUMBERI

" Band One-ThirdOctaveBandSoundPressurLe vel,dBre20microPa

Center ......................................................................

Frequency TestCondition

Hz I0 II 12 13 14 15 16 17 18

.................................................................................. i

25 88.5 7B.B 85.0 93.5 93.0 92.5 90.3 93.8 91.5

32 80.8 79.8 79.8 BI.3 BI.5 BO.O 79.5 82.5 B0.3

40 69.0 66.5 68.3 65.3 65.3 64.5 65.3 66.0 65.5

50 77.3 70.0 74.5 70.8 69.5 65.8 70.5 71.0 71.0

63 97.0 87.5 94.5 90.3 88.5 84.5 90.5 88.3 89.8

80 111.8 101.0 108.5 104.5 102.8 99.5 104.8 105.5 103.5

I00 91.0 81.8 86.3 83.0 82.5 79.8 83.3 86.3 83.5

125 85.8 81.0 Bl.O 85.3 80.3 83.0 84.8 81.0 82.5

160 96.8 83.5 84.0 98.8 85.3 95.8 97.9 90.8 95.8

200 88.8 84.3 81.5 84.3 87.0 86.5 86.8 86.5 88.5

250 92.0 87.5 83.0 87.3 92.0 91.5 91.8 92.3 94.3

315 92.8 83.5 84.5 86.5 85.5 85.5 83.0 81.5 91.0

400 88.0 83.5 81.3 84.5 82.5 84.0 86.0 84.5 86.3

500 90.8 85.8 84.0 88.8 88.0 88.5 87.3 90.3 87.5

630 86,5 80.3 79.0 82.5 81.8 82.3 82.0 83.3 83.0

810 84.8 79.3 78.0 79.0 79.3 79.0 80.0 80.0 80.8

I000 86.0 78.8 79.0 79.5 80.5 BO.O B0.3 80.5 80.8

1250 83.5 75.8 75.3 78.5 78.8 78.8 79.0 78.8 78.8

1600 81.5 74.5 73.8 77.0 78.0 78.8 78.8 77.8 77.3

2000 BO.O 72.5 73.3 74.3 73.3 75.0 74.8 74.3 74.0

2500 77.0 70.8 70.8 71.3 70.0 71.8 71,8 70.8 70.8

3150 75.0 69.0 69.0 69.3 67.8 69.3 70.3 69.0 69.0

4000 72.3 66.3 66.8 67.5 64.8 67.8 69.3 67.0 67.0

5000 69.8 65.0 67.3 65.0 63.0 65.8 66.3 64.B 65.0

NA NotAvailable

-169-
TAB LE E. 2

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELSFLI , GHT13

CABINMICROPHONUMBER NE 2

w

Band One-ThirdOctaveBandSoundPressureLevel, dBre 20microPa "

Center ..................................................................................

Frequency TestCondition -

Hz l 2 3 4 5 6 7 8 9 "

25 79.3 79.0 81.3 80.8 85.3 85.0 83.5 81,8 84.0

32 BO.5 BO.0 73.3 75.5 74.B 75.5 75,3 75,0 76.B

40 72.5 73.3 66.B 67.5 66.3 65.0 66.B 67.0 66.8

50 B0.3 79.5 78.5 80.0 77.8 76.0 79.3 79.0 79.3

63 94.5 96.B 97.0 96.0 96.5 93.5 9B.3 97.3 95.5

BO III.8 111.3 III.B 113.5 111.3 IOB.5 113.0 112.3 113.3

100 92.8 89.8 90.0 94.0 89.5 87.5 90.8 90.5 94.0

125 87.0 86.5 89.0 89.0 B9.3 90.3 89.3 90.8 89.8

160 94.0 94.0 97.3 96.5 100.3 102.0 95.5 103.0 100.3

200 88.0 88.0 88.3 87.0 B7.B 89,0 90.5 90.8 89.0

250 91.8 91.0 92.5 94.5 91.0 93.3 95.3 95.8 94.3

315 91.5 89.0 92.8 97.5 92.5 89.0 88.5 90.8 94.3

400 B7.0 86,8 BB.8 90.0 89.8 91.0 B9.B 90.3 90.8

500 86.8 B6.B 89.0 90.3 o¢.8 92.8 92.5 92.0 93.0

630 88.0 86.8 88.5 90.3 89.3 89.0 89.8 88.5 9(1.3

800 87.0 86.8 87.5 88.5 86.5 87.5 87.0 87.8 88.0

I000 86.5 B5.B 86.8 87,3 87.3 87,3 87,0 B7.B BB,3

1250 85.0 85.0 84.3 85.3 84.3 85.0 85.0 85.0 84.8

1600 83.0 81.8 81.3 82.8 81.5 82.5 83.3 82.3 82.5

2000 BO.O BO.O BO.O BO.B 79.3 80.3 80.3 B0.5 B0.8

2500 77.0 76.3 77.0 78.0 76.8 78.5 79.5 78.3 78.5

3150 73.5 73.3 75.5 76.3 74.8 76.3 76.5 75.3 76.0

4000 72.0 71.3 74.3 75.0 72.5 74.3 75.3 73.3 74.3

5000 70.5 69.5 73.3 72.8 70.5 72.8 74.0 71,5 72.3

..................................................................................

NA NotAvailable

-170-
TABLE E.2 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURLEE VELS. FLIGHT13

CABINMICROPHONENUMBE2R

8and One-ThirdOctaveBandSoundPressureLevel,dBre20microPa

Center .....................................................................

Frequency TestCondition

Hz 10 11 12 13 14 15 16 17 18

25 83.3 73.B B0.3 BB.O B8.0 B6,B B4.B 88.0 B5.8

32 75.0 75.5 75.3 76.8 76.B 75.3 75.0 77.3 75.b

40 66.5 62.0 65.0 61.0 61.0 60.0 61.0 /,I.3 60.8

50 77.5 71.5 75.8 70.8 71.0 69.5 71.0 72.0 71.5

63 97.0 85.5 95.3 88.8 B8.5 85.3 88.5 86.B 88.0

80 111.8 98.5 I09.0 103.0 103.0 99.5 103.0 104.3 102.5

100 90.0 78.8 86.3 82.0 81.B 79.3 81.8 85.0 82.0

125 90.5 84.0 87.3 86.3 85.5 85.0 87.0 85.0 86.5

160 100.5 8B.5 96.3 97.5 91.B 92.5 98.5 93.8 95.3

200 89.5 82.8 84.5 85.5 83.8 83.5 84.5 85.3 83.3

250 93.8 85.5 89.3 88.5 85.8 84.8 85.5 90.3 84.5

315 91.0 84.3 85.8 91.3 91.5 89.3 B6.5 87.5 90.0

400 91.0 84.8 83.0 88.0 86.8 87.0 86.0 87.5 90.0

500 91.8 85.5 85.0 92.5 88.8 88.8 89.3 94.0 92.0

630 88.5 81.5 82.5 84.8 85.3 85.0 84.8 86,0 85.3

800 87.8 81.8 81.0 82.0 81.5 82.0 81.8 82.5 83.0

I000 87.5 80.8 81.3 81.5 BI,O Bl.B 81.5 81.5 82.0

1250 84.8 77.0 76.3 79.3 79.3 80.5 80.8 79.B 79.8

1600 82.3 75.3 74.3 78.0 78.5 79.5 79.5 77.8 80.3

2000 80.0 73.5 74.0 74.3 73.5 74.5 74.8 74.3 74.5

2500 78.0 72,0 72.0 72,0 71.3 72,5 72,8 72,0 72.3

3150 75.8 70.3 70.3 70.B 68.8 71.0 71.8 70.0 70.8

4000 74.3 67.8 68.8 69.3 66.8 69.5 69.8 68.5 68.8

5000 71.5 67.3 69.5 67.5 65.0 67.8 68.0 66.5 67.0

......................................... . ...................................................

NA NotAvailable

-171-
TABLE E. 3

ONE-TH!RDOCTAVEBANDSOUNDPRESSURLEE VELS.FLIGHT13

CABINMICROPHONENUMBER3

Band One-ThirOcdtavBae ndSoundPressureLevel,dBre20microPa

Center .......................................................................

Frequency TestCondition .

Hz 1 2 3 4 5 6 7 B 9

..................................................................................

25 74.5 75.3 77.3 75.0 78.5 78.3 76.0 76.0 78.3

32 72.8 73.0 69.0 69.3 69.3 69.3 68.0 73.8 71.0

40 66.8 66.5 62,8 63,8 62.5 63.5 62,5 70.0 63,0

50 80.5 79.0 76.5 79.0 76.5 76.5 75.0 76.8 76.8

63 89.8 90.0 86.8 87.0 B6.0 91.5 88.8 83.0 87.3

80 106.5 103.8 100.5 102.0 99.0 106.3 102.5 93.0 100.3

I00 89.0 B5.5 86.0 87.0 85.3 88.0 86.8 86.3 86.3

125 88.0 86.5 88.8 88.8 89.3 90.5 87.5 91.0 89.0

160 98.5 96.3 98.3 97.0 101.3 102.8 95.0 104.8 99.8

200 95.3 93.0 91.3 92.3 88.0 91.0 90.8 91.8 91.5

250 100.3 98.8 97.5 100.0 89.5 95.5 95.5 96.3 98.3

315 90.8 90.3 91.0 89.3 90.3 91.8 91.8 89.5 90.3

400 89.8 BB.5 90.3 93.3 92.0 91.8 90.3 91.5 91.5

500 89.0 8B.3 93.5 94.0 93.0 92.5 93.0 93.0 92.3

630 92.8 91.0 93.3 93.5 92.8 95.3 95.3 93.5 93.8

800 90.3 89.3 90.8 92.0 90.8 91.5 91.8 91.3 91.5

1000 B8.5 88.0 89.5 91.0 90.0 90.8 90.8 90.5 90.5

1250 86.5 B5.B 86.3 87.3 86.0 87.3 87.0 87.3 B7.3

1600 85.0 84.5 83.8 85.3 84.0 85.0 85.0 85.0 85.0

2000 82.3 B2.5 BI.3 82.5 BI.5 82.5 82.B 82.5 82.5

2500 7g.0 7B.B 78.3 7g.5 7B.B 7g.5 BO.O 79.8 BO.O

3150 74.8 "41.3 76.0 77.3 76.5 76.8 77.8 77.3 77.3

4000 73.5 73.0 74.5 75.8 74.0 75.0 75.5 74.8 75.3

50i)0 71.3 71.0 73.0 73.5 73.0 73.3 73.8 73.0 73.5

NA NotAvailable

-172-
TABLE E.3 (CONTINUED)

0NE-THIRDOCTAVEBANDSOUNDPRESSURELVELS.FLISHT#3

CABINMICROPHONENUMBER3

_. Band One-ThirdOctaveBandBoundPressurLe vel,dBre20microPa

Center .......................................................................

Frequency Test Condition

Hz 10 11 12 13 14 15 16 17 18

25 77.3 70.3 75.5 83.0 72.8 82.3 81.0 82.8 80.8

32 6%8 69.0 69.3 70.3 70.B 69.8 6%0 71.8 69.8

40 63.3 61.8 62.3 62.0 61.8 63.0 62.5 62.3 69..c50 75.8 73.5 74.8 71.3 71.8 72.5 72.5 73.0 72.0

63 BB.O B7.0 87.5 B3.B 82.5 BB.B B5.3 B3.5 86,3

BO 103.3 I00.0 I01.3 97.0 95.5 103.0 99.0 ?B.O I01.0

100 86.8 83.8 83.8 B2.5 83.3 84.3 B3.3 83,0 84.8

125 89.8 85.3 88.0 85.0 85.3 87.0 83.B 84.3 85.5

160 101.8 92.8 97.3 96.3 96.3 99.5 92.3 %.3 97.3

200 90.3 8_.3 83.5 84.3 B5.B 86.3 85.5 84.B 85.5

250 75.0 90.5 87.0 84.8 BB.8 B9.3 88.5 84.5 BB.O

315 91.0 85.5 81.0 85.5 89.3 BB.3 B6.5 B6.B B7.3

400 90.3 85.5 84.0 90.8 90.5 90.5 89.8 91.5 89.5

500 °.3.5 87.0 85.B .°5.5 95.5 95.8 95.0 96.5 %.0

630 93.8 89.3 87.5 90.5 90.0 90.0 8%3 BB.3 92.0

BOO 71.5 8,_.,, 83.8 86.0 86.0 86.5 B_.5 B6.0 B7.3

1000 ?O.B B",.t_",.., 82.5 84.0 84.5 B4.B B4.5 84.3 B4.3

1250 87.0 79.3 78.3 B2.B B3.3 B3.B 83.3 83.0 B3.3

1600 B4.5 77.B 77.3 BO.B 82.0 BI.O BO.B B0.3 B0.5

2000 82.3 75.5 76.8 77.0 76.5 77.3 77,8 76,8 77,3

2500 79.5 74.3 74.0 74.8 73.8 74.5 74.3 74.3 74.8

5 3150 77.0 71.0 71.5 72.5 71.0 72.0 73.0 72.5 7_._

4000 74.8 69.3 70.0 71.0 69.8 71.0 71.5 70.8 70.8

5¢P00 73.3 _8.3 70.5 70.0 68.5 69.5 70.5 69.5 69.5

.............................................................................................

NA NotAvailable

-173-
TABLE E. 4

ONE-THIRDOCTAVEBANDSOUNDPRESSURLEVELS. E FLIGHT13

CABINMICROPHONENUMBER4

Band One-ThirdOctaveBandSoundPressurLeevel,dBre20microPa

Center .......................................................................

Frequency TestCondition

Hz 1 2 3 4 5 6 7 8 9

25 85.0 B5.B 88.5 86.8 91.0 90.8 Bg.5 88.3 90.0

32 75.3 85.3 79.5 80.8 80.5 81.0 80.3 BO.B 82.8

40 71,B 72.5 69.3 70.3 69.0 69.8 69.0 69.3 69.8

50 74.3 73.5 73.0 74.3 73.5 73.0 75.3 74.0 74.5

63 92.0 90.0 87.8 92.3 90.3 86.0 92.5 91.5 92.3

BO 109.3 105.0 104.0 I08.5 104.5 100.0 107.5 106.5 108.3

100 90.3 86.0 87.0 B9.B 86.5 84.0 88.0 B7.B 89.3

125 87.8 87.0 88.8 87.8 8B.8 86.0 87.0 89.3 87.5

160 95.0 95.3 101.3 102.3 10!.5 95.3 97.5 102.0 100.5

200 88.0 88.3 86.0 88.5 87.0 85.5 85.0 86.0 87.0

250 88.5 87.5 85.5 85.8 86.5 87.0 87.3 87.B 88.5

315 90.3 88.8 90.5 92.8 90.3 90.5 91.8 92.0 93.8

400 90.5 89.0 91.5 92.3 92.5 91.0 92.5 91.5 92.0

500 89.B 89.5 %._ 93.3 92.3 a',3' 92.0 92.0 92.8

630 91.0 90.0 91.8 94.0 94.5 94.3 95.0 94.5 94.3

800 89.5 89.0 9!.3 92.8 91.0 91.5 91.8 92.0 92.0

1000 89.3 88.8 91,3 92.5 90.8 91.0 91.5 91.3 91.0

1250 87.5 87.3 87.3 88.5 88.3 88.8 88.5 BB.5 BB.8

1600 85.5 85.3 84.0 85.5 84.8 85.5 85.5 85.5 85.0

2000 82.0 8!.5 81.3 82.3 81.3 82.5 82.3 82.5 8_.u

2500 78.5 77.5 77.0 78.5 77.5 78.3 79.0 78.5 78.5

3150 73.5 73.0 75.0 76.0 75.0 76.0 76.5 76.5 76.3

4000 71.5 70.8 72.8 74.0 72.5 73.8 74.5 73.3 73.5

5000 69.3 69.0 70.8 71.8 71.3 71.3 72.3 71.8 72.0

NA NotAvailable

-174-
TABLE E,4 (CONTINUED)

8NE-]HIRDOCIAVEBANDSDUNDPRESSURLEVE ELS.FLIBHT13

CABINffICROPHONE NUMBER4

Band I One-ThirdOctaveBandSoundPressureLevel,dBre20microPa

tenter I.......................................................................

FrequencyI TestCondition

Hz I 10 II 12 13 14 15 16 17 18

25 I 8%3 80.5 86.5 94.8 94.5 93.8 92.3 95.3 93.0

32 I 81,0 81.0 80.8 82.0 82.3 BO.B 80.5 83.0 81.3

40 : 69.8 68.8 68.8 68.3 68,5 69.0 68.5 69.0 6%0

50 I 73.3 71.3 65.5 68.8 66.0 69.0 69.0 69.5 70.0

63 I B9.3 90.5 73.5 85.3 75.0 88.0 87.8 Bb.5 85.5

80 I 106.5 103.8 85.5 I00.0 88.3 102.3 102.3 !02.0 102.5

I00 ; B8,B 83.8 81.0 81.8 80.5 83.0 82.8 83°8 84.5

125 l 88.0 82.8 86.3 81.5 82.0 8_=.5 BI.B 81._= 82.5

160 I 98.3 91.3 97.5 91.0 89.8 94.3 90.0 90.5 93.0

200 I B6.B 81.B 79.8 83.5 83.8 93,8 83,5 B3,B 84.3

250 I 88.8 7B.3 80.8 77.8 83.3 82.5 81.5 84.0 79.8

315 I 89.3 85.0 B3.0 84.3 84.0 84.5 85,0 84.8 86.0

400 I 92.0 88.5 86.5 89.3 89.5 89.3 88,5 BB.3 91.B

500 I 92.3 88.0 85.3 93.0 91.5 92.0 90.0 91.0 90.5

630 I 92,5 91.0 84.5 89.5 90.5 90.3 90.8 9!.5 90.0

BOO I 91.0 86.3 83.8 84.5 86.0 BS.B 86.3 86.5 86.5

I000 I 91.0 B4.B 83.5 84.5 85.0 B6.0 B5.5 85.3 85.8

1250 I BB.O B2.0 79.8 83.3 B3.5 83.3 84.0 83.B 84.0

1600 I 85.3 78.3 76.8 81.5 81.0 81.8 81.5 81.3 81.5

2000 I 82.0 75.3 74.8 76.0 76.5 77.0 77.0 76.3 77.0

2500 I 78.8 72.3 72.3 72.8 73.0 73.5 73.5 72.8 73.0

3150 I 75.8 70.5 70.3 72.0 71.3 71.5 72.5 71.5 71.8

4000 I 73.3 67.5 67.B 70.0 69.3 69.5 70.B 70,0 70.0

5000 I 71.0 66.3 67.8 68.8 67.B 68.3 69.0 68.e 68.5

I..................................................................................

NA NotAvailable

-i'/5-
TABLE E. 5

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT13

CABINMICROPHONE NUMBER5

Band One-ThirOctave d BandSoundPressureLevel,dBre20microPa :

Center ......................................................................

Frequency TestCondition

Hz l 2 3 4 5 6 7 8 9 -

..................................................................................

25 72.3 72.3 73.5 72.5 75.3 76.0 75.3 74.0 73.5

32 70.5 70.8 65.0 66.0 66.3 67.3 65.3 66.3 67.5

40 65.5 66.0 61.5 62.0 61.0 60.3 60.5 60.8 61.0

50 81.0 79.3 77.3 80.3 76.3 74.3 74.0 76.0 78.3

63 86.3 85.5 82.5 85.5 81.0 BO.O 81.0 7%8 82.5

80 I01.0 99.5 95.5 101.0 91.8 B3.B 92.3 87.5 97.0

I00 85.3 84.3 85.0 86.3 85.0 83.5 84.8 BS.B 85.8

125 8%0 8%8 91.5 91.0 93.8 87.0 91.8 92.8 90.5

160 104.5 104.0 105.8 I(16.5 108.5 97.3 105.5 107.5 106.0

200 90.3 90.3 90.3 89.8 90.5 87.8 BB.B BB.5 89.5

250 95.3 93.8 94.5 92.3 94.0 91.5 92.3 88.3 91.3

315 88.5 89.3 8%0 89.5 87.3 91.8 90.5 87.3 92.5

400 87.5 87.8 90.3 91.0 90.5 90.8 91.0 91.3 93.3

500 88.3 88.0 91.8 94.3 90.5 91.3 91.3 91.5 94.0

_30 89.8 8_.8 92.3 92.0 92.5 91.8 91.5 90.8 91.8

800 88.5 88.5 90.3 9!.5 89.8 90.5 90.5 8%8 90.5

1000 87.5 87.3 8%0 89.3 88.8 89.5 Bg.5 89.0 89.5

1250 B5.B 86.0 85.5 86.5 86,3 86,5 86.8 86.3 B6.8

1600 84.8 84.0 83.0 84.3 84.0 84.0 84.5 84.3 84.0

2000 81.5 81.5 80.8 82.0 80.8 81.8 82.0 81.5 81.5

2500 77.3 77.8 77.3 78.5 77.5 78.3 78.5 78.5 78.0

3150 74.0 73.5 74.8 76.0 75.3 75.8 76.5 75.5 76.3

4000 71.B 71.0 73.3 74.3 73.3 73.5 74.5 73.5 7.4._ =

50!)0 69.8 69.5 71.3 71.B 71.3 71.8 72.5 _,_._'_71.8

NA NotAvailable

-176-
TABLE E.5 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT13

CABINMICROPHONE NUMBER5

Band I One-ThirdOctaveBandSoundPressureLevel,dBre20microPa ',

Center :.......................................................................

Frequency{ TestCondition

Hz { 10 11 12 13 14 15 16 17 18

25 : 73.8 6&.3 71.5 79.0 79.0 7B.B 76.8 79.3 77.0

32 : 65.3 65.8 66.0 67,0 67.0 66,5 66.0 68,0 66.5

40 I 61.0 59.0 59.5 60.5 60.0 60.0 60.0 60.5 60.5

50 _ 75.5 71.8 73.8 71.8 72.0 70.3 71.3 73.8 70.5

63 l 81.0 82.8 79.5 84.0 83.5 79.0 83.0 BI.B 78,5

80 ', q4.5 95.3 B7.B 9B.3 97.5 90.0 96.5 94.5 91.5

100 : B4.3 82,0 BI.3 Bl.O BI.5 BO,B BO.B B0.3 B0.3

125 : 91.8 86.3 89.5 83.0 90.0 BB.O B2.3 86.0 B7.3

16;- : 107.0 97.3 102.5 93.3 104.3 I01.B 91.3 101.5 102.8

200 I 90,8 85,5 82.5 BB.O 86.0 85,0 84.5 86.3 87.5

250 I 93,5 89,8 84.3 92,8 B6.B 86,5 B7.8 87,8 %..

315 I 91,0 85.3 80.3 B3.B 83.8 86,3 B3.3 B5,0 B8.5

400 ( 91.0 84.0 86.0 90.8 8B.8 91.5 B9.0 89.0 92.0

500 : 91.5 Bb.3 86.0 9!.3 92.0 92.3 91.3 93.3 91.5

630 I 91.5 87.5 84.5 8_.0 88.8 88.8 B9.0 89.0 88.5

800 : ?(!.5 84,0 82.5 84.5 B5.0 85.0 B4.B 85.3 86.3

I000 I B9.0 82.0 Bl.O 83.3 83.5 B3.3 B3.3 83,5 83,5

1250 I 86.5 79.0 78.0 BI,5 82.0 B2,5 82.3 82.3 82.3

1600 l 83.5 76.8 76.8 79.3 79.5 79.8 79.3 80.0 79.5

2000 : 82.0 75.0 75.3 75.5 75.5 75.8 76.5 76.0 76.0

2500 : 78.3 72.5 73.3 72.5 72.5 72.8 L._ 73.0 73.3

3150 l 75.8 69.3 71.0 71.3 6.0.5 71.0 71.3 70.8 71.0

4000 : 73.8 6B.0 69.0 69.8 68.0 69.0 70.0 69.0 69.0

5000 I 71.8 65.B 6%3 67.8 66.5 67.3 6B.3 67.3 67.5

NA NotAvailable

-177-
TAB LE E. 6

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT13

CABINMICROPHONE NUMBER6

Band One-ThirdOctaveBandSoundPressureLevel,dBre20microPa

Center .................................................................................. "

Frequency TestCondition

Hz 1 2 3 4 5 6 7 B 9 ."

25 84.8 85.3 88.3 87.3 91.0 91.3 90.5 88.8 90.5

32 85.8 86.0 80.0 81.5 81.3 82.3 81.0 81.0 83.(I

40 72.5 73.0 70.0 70.8 69.5 70.0 6°..5 69.8 70.3

50 73.5 73.3 73.3 75.3 73.0 72.8 75.8 74.0 74.3

63 91.5 90.8 91.0 93.3 90.0 B2.0 93.5 92.5 92.5

80 108,5 106,3 106,3 110,5 104,8 96,3 108,5 107,0 II0,0

100 90°0 87,3 87.5 92,0 86,0 84,3 88,5 87,5 91,5

125 BG,B 86,8 86,5 87,0 88,0 84,3 86,8 8B,8 87,3

160 9B,B 9B,3 100,0 100,3 101,5 90,8 99,3 102,0 102,0

200 88,5 89,0 87,3 85,5 85,8 84,8 85,8 87,5 Bb,G

250 91,3 0.1,5 85,3 BB,8 81,5 84,5 83,0 B5,B 88,5

315 91,0 90,8 80.,8 92,5 90,3 90,0 89,8 90,8 91,3

400 91,5 90,8 93,0 95,3 91,5 92,3 92,3 92,3 93,8

500 90,5 S9.B 93,0 93,8 92,3 93,, 92,8 92,8 93,0

b30 92,8 93,0 94,5 95,0 9.3,5 93,5 93,8 93,3 94,3

800 90.8 90.8 92.8 93.0 91.8 92.8 92.8 93.0 92.8

I000 89,8 89,3 90,8 0.1,5 91,5 91,8 91,5 91,8 91,8

1250 88.5 8B,0 87,5 89,3 88,5 89,0 89,3 88,5 89,0

1600 85.5 B5.B 84.5 86.0 85.3 86.3 86.3 86.0 86.0

2000 83.0 82.3 81.5 82.5 82.0 82.8 83.0 83.0 83.3

25(i0 79.0 78.8 77.5 79.0 78.8 79.0 79.3 79.5 79.5

3150 74.0 74.0 75.3 76.3 75.8 76.5 76.8 76.0 76.0

4000 71,5 71,0 72,5 73,8 73,0 73,8 74,0 73,8 73,8

5000 69,3 6B,8 70,3 71,5 71,0 71,0 72,0 71,0 71,5

..................................................................................

NA NotAvailable

-1'78-
TABLE E.6 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT13

CABINMICROPHONE NUMBER6

Band One-ThirdOctaveBandSoundPressurLe vel,dBre 20aicroPa

Center -......................................................................

Frequency TestCondition

Hz 10 11 12 13 14 15 16 17 18

25 89.5 81.3 86.8 95,0 95.0 94.3 92.0 95.0 93.0

32 BI.5 B2.0 BO.B 82.5 B2.B Bl.B 81.0 84.0 BI.5

40 70.0 69.3 69.3 69.0 69.0 69.0 69.0 69.3 69.5

50 73.B 70.0 68.0 66.3 64.0 66.5 67.3 67.5 67.B

63 90.8 B61B 84.3 B3.B 76.5 84.5 B6.0 85.0 B4.3

BO 106.8 99.5 98.0 98.0 90.0 99.0 100.5 I01.8 100.3

100 BB.3 83.0 82.3 81.3 81.5 8_-5. B2.5 84.3 83.3

125 86.0 85.0 B0.3 B0.5 B6.0 B4.B B0.5 83.3 B2.B

160 97.3 96.5 B8.0 89.0 100.0 98.3 90.5 96.5 95.5

200 B7.B 81.3 79.8 85.3 84.8 83.5 82.8 B4.B 86.0

250 86.8 81.3 82.0 85.0 79.8 80.3 79.0 8._.0 89.8

315 91.0 86.3 87.5 85.5 B4.5 86.0 B5.5 85.3 85.5

400 91.B 87,0 8B.0 88.B 88.5 88.5 B7.8 88.5 89.8

500 93.0 87.0 86.0 90.0 88.3 90.,, BB.B B9.5 90.3

630 94.0 88.0 86.5 91.5 _0.3 91.3 90.0 91.8 92.0

BOO 92.B 86.0 B4.B 86.3 86.8 87.0 BS.B B7.0 BB.3

IC.O0 91.3 85.0 82.8 84.8 85.5 85,0 85.5 85.3 B5.0

1250 88.8 81.3 Bl.O B4.0 B4.3 84.3 B4.3 84.0 84.3

1600 85.5 78.5 77.3 82.0 82.3 B2.5 82.5 82.0 82.5

2000 82.5 76.0 75.8 77.3 77.0 77.0 77.B 77.3 77.5

2500 78.8 73,3 72.5 74.0 73.8 74.5 74.8 73,8 74.0

3150 76.3 70.8 70.8 71.8 71.B 72.0 72.3 71.5 72.3

4000 73.5 67.8 68.5 69.8 69.0 69.5 70.B 69.8 69.8

5000 70.8 66.3 67.5 67.B 67.5 67.B 68.5 68.0 68.3

NA NotAvallable

-179-
-180-
APPENDIX F

One-Third Octave Band Spectra for InteriorSound Pressures:

Flight 4, Interior Treated with Fiberglass.

-181-
TABLE F. I

ONE-THIRDOCTAVEBANDSOUNDPRESSURELVELS,FLIGHT14

CABINMICROPHONENUMBERI

Band One-ThirdOctaveBandSoundPressureLevel, dBre 20microPa

Center .................................................................................

Frequency Test Condition

Hz I 2 3 4 5 6 7 B 9

25 97.5 97.0 101.5 102.3 NA NA NA NA 102.3

32 B5.3 83.0 85.0 8B.3 NA NA NA NA 88.8

40 74.0 73.5 69.3 70.0 NA NA NA NA 69.5

50 74.5 76.0 77.5 74.5 NA NA NA NA 74.8

63 89.5 91.B 95.3 93.3 NA NA NA NA 93.0

80 105.3 107.0 110.3 109.5 NA NA NA NA 110.0

100 B7.B 88,0 90.8 90.5 NA NA NA NA 91.0

125 85.8 86.5 BB.O 87.0 NA NA NA NA 86.0

160 IOI.B 101.0 102.3 101.5 NA NA NA NA 101.5

200 B9.0 88.0 87.0 B7.B NA NA NA NA 88.5

250 91.5 90.3 B8.B 89.B NA NA NA NA 89.5

315 B5.3 85.8 84.8 B4.3 NA NA NA NA 83.3

400 B3.5 84.3 86.5 86.0 NA NA NA NA 85.5

500 87.5 87.5 88.0 B8.0 NA NA NA NA 88.5

630 85,3 85.5 87.3 86.8 NA NA NA NA 86.8

800 82.0 82.8 84.8 84.8 NA NA NA NA 82.5

1000 84.0 BS.B B4.0 B4.0 NA NA NA NA B2.3

1250 81.3 81.0 79.3 79.8 NA NA NA NA 78.3

1600 80.5 80.0 79,5 79.5 NA NA NA NA 79.3

2000 79.0 77.5 78.0 7B.B NA NA NA NA 76.8

2500 75,3 74.B 76.3 76.5 NA NA NA NA 75.5

3150 70.0 70.3 72.5 72.0 NA NA NA NA 72.0

4000 66.8 66.5 68.8 6B.5 NA NA NA NA 67.3

5000 64.3 63.8 66.B 67.0 NA NA NA NA 66.0

NA NotAvailable

-182-
TABLE F.I (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT14

CABINMICROPHONENUMBERI

Band One-ThirdOctaveBandSoundPressureLevel, dBre 20 microPa

Center ..................................................................................

Frequency TestCondition

Hz I0 II 12 13 14 15 16 17 IB

25 101.8 93.8 99.5 103.0 NA NA NA 106.0 104.5

32 85.5 77.3 82,5 85,5 NA NA NA 92.3 8B.0

40 69.5 64.8 68.0 67.8 NA NA NA 71.8 69.3

50 78.3 70.5 74.5 73.0 NA NA NA 71.8 73.3

63 96.5 90.3 94.5 92.8 NA NA NA 89.5 91.5

BO 111.5 103.0 108.8 106.8 NA NA NA 105.3 106.3

100 91.8 83.5 87.8 85.3 NA NA NA B6.B 86.5

125 86.3 B1.B 83.3 BO.B NA NA NA 80.3 80.3

160 98.B 92.3 92.5 92.0 HA HA NA 94.5 94.0

200 88.3 83.3 BI.3 B4.0 NA NA NA 85.5 B4.B

250 B9.3 80.3 BO.O 85.5 NA NA NA B7.8 86.0

315 83.8 78.5 76.3 76.3 NA NA NA BO.O B0.8

400 B5.5 BI.5 BI.B 79.B HA NA HA B2.3 81.3

500 88.3 85.0 83.3 83.5 NA NA NA 85.5 85.5

630 B6.5 83.0 79.5 80.5 NA NA NA 79.0 80.3

800 83.8 79.5 77.5 79.8 NA NA NA 81.3 B0.3

1000 82.8 77.3 77.3 77.0 NA HA HA 78.0 77.5

1250 79.5 73.3 72.5 73.5 NA NA NA 74.3 74.3

1600 79.B 73.5 71.3 72.8 NA NA NA 74.3 73.B

2000 7%0 72.0 6B.B 70.8 NA NA NA 72.0 72.0

2500 76.5 69.3 68.0 6B.0 NA N_ HA 69.3 69.5

3150 72.5 68.0 66.5 66.0 NA NA NA 67.0 66.3

4000 68.5 65.0 64,5 62.3 NA NA NA 62.B 62.8

5000 66.8 63.8 63.8 61.5 NA NA NA 62.3 62.0

NA NotAvailable

-183-
TABLE F. 2

ONE-THIRDOCTAVEBANDSOUNDPRESSULREVE ELS. FLIGHT14

CABINMICROPHONUNEMBER2

Band One-ThirOctave d BandSoundPressurLee vel,dBre20microPa

Center .......................................................................

Frequency TestCondition

Hz I 2 3 4 5 6 7 B 9 "

25 84.0 83.8 88.0 89.0 NA NA NA NA 88.5

32 73.8 72.3 71.3 74.5 NA NA NA NA 75.0

40 72.5 72.8 68.8 68.0 NA NA NA NA 67.0

50 84.3 83.3 83.8 85.8 NA NA NA NA 84.5

63 93.0 94.5 Y8.O 96.8 NA NA NA NA 96.0

80 108.3 109.5 112.5 112.0 NA NA NA NA 112.0

I00 88.3 88.8 ?l.B 91.5 NA NA NA NA 92.0

125 89.0 90.0 89.3 89.5 NA NA NA NA 88.0

160 102.5 101.3 97.8 I00.0 NA NA NA NA 97.5

200 86.0 84.5 83.8 84.8 NA NA NA NA 84.0

250 84.8 83.5 82.5 84.0 NA NA NA NA 83.5

315 80.5 79.5 78.5 78.0 NA NA NA NA 76.5

400 76.3 76.0 81.3 82.5 NA NA NA NA 82.0

500 74.8 75.3 79.5 79.3 NA NA NA NA 81.8

630 73.0 72.8 76.3 77.3 NA NA NA NA 76.0

800 72.5 71.5 74.0 74.3 NA NA NA NA 73.8

1000 72.3 71.8 72.0 72.5 NA NA NA NA 71.3

1250 69.3 69.8 68.8 68.8 NA NA NA NA 67.8

1600 _7.3 66.8 67.3 67.3 NA NA NA NA 66.0

2000 64.8 65.0 65.0 64.5 NA NA NA NA 64.5

2500 62.8 61.8 62.5 62.3 NA NA NA NA 62.3

3150 60.0 60.0 61.5 61.8 NA NA NA NA 61.0

4000 60.0 60.0 61.0 61.0 NA NA NA NA 60.8

5000 60.0 60.0 60.3 60.5 NA NA NA NA 60.0

NANotAvailable

-184-
TABLE F.2 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNPDRESSURELVELSFL, IGHT#4

CABINMICROPHONENUMBER2

. Band One-ThirdOctaveBandSoundPressureLevel, dBre 20 microPa

Center ..................................................................................

Frequency TestCondition

= Hz I0 II 12 13 14 15 16 17 18

25 88.0 79.8 86.0 88.5 NA NA NA g2.0 90.0

32 72.0 64.3 69.0 70.8 NA NA NA 78.0 73.5

40 68.3 65.0 66.0 64.3 NA NA NA 64.5 64.5

50 83.8 76.8 79.3 76.8 NA NA NA 77.5 77.8

63 98.8 95.3 96.3 94.5 NA NA NA 91.5 93.0

80 113.5 109.0 110.3 108.5 NA NA NA 107.3 108.3

I00 92.0 86.8 88.3 86.5 NA NA NA 87.5 87.3

125 89.5 85.5 87.0 86.0 NA NA NA 86.5 86.0

160 98.0 92.8 95.5 96.0 NA NA NA 98.3 97.5

200 85.5 81.5 81.8 81.8 NA NA NA 82.8 81.8

250 87.3 79.5 85.3 84.8 NA NA NA 85.8 82.0

315 77.3 73.5 71.0 74.5 NA NA NA 74.3 79.8

400 82.0 75.8 73.3 75.0 NA NA NA 76.5 76.8

500 82.8 74.8 75.3 77.0 NA NA NA 80.5 80.0

630 75.0 73.0 67.3 71.5 NA NA NA 73.5 72.3

SO0 73.3 68.0 67.0 67.5 NA NA NA 70.0 69.5

1000 71.8 66.8 65.8 65.5 NA NA NA 66.3 6_.8

1250 69.0 63.5 61.8 62.8 NA NA NA 64.3 63.5

1600 66.5 61.0 60.0 60.0 NA NA NA 60.8 60.5

2000 65.5 60.3 60.0 60,0 NA NA NA 60.0 60.0

2500 62.8 60.0 60.0 60.0 NA NA NA 60.0 60.0

3150 6!.3 60.0 60.0 60.0 NA NA NA 60.0 60.0

4000 61.0 60.0 60.0 60.0 NA NA NA 60.0 60.0

5000 60.8 60.0 60.0 60.0 NA NA NA 60.0 60.0

NANotAvailable

-185-
TABLE F. 3

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIBH14T

CABINMICROPHONEHUMBER3

Band One-ThirdOctaveBandSoundPressureLeve!,dBre20microPa

Center ......................................................................

Frequency TestCondition .

Hz I 2 3 4 5 6 7 B 9 "

..................................................................................

25 88.0 8B.0 91.8 92.3 NA NA NA NA 92.0

32 74.5 72.0 75.5 78.0 NA HA NA NA 78.5

40 70.5 70.8 68.3 68.0 NA NA NA NA 66.3

50 84.8 84.3 85.0 86.0 NA NA NA NA 84.5

63 90.0 92.0 90.8 89.B NA NA NA NA 88.5

80 107.8 106.5 105.0 I07.0 NA NA NA NA 105.5

100 89.5 86.5 87.5 89.3 NA NA NA NA 88.3

125 85.3 84.3 85.0 86.5 NA NA NA NA 85.5

160 99.0 94.3 92.8 98.0 NA NA NA NA 95.5

200 BS.5 86.0 84.8 87.0 NA NA NA HA 86.0

250 93.0 93.8 91.8 92.3 NA HA NA NA 91.8

315 78.5 80.0 85.3 85.0 NA NA NA NA 85.8

4(,0 77.8 77.3 83.5 83.8 NA HA HA NA 83.5

500 76.0 76.8 80.3 80.5 NA HA NA NA 83.0

eSO 75.5 74.8 77.5 79.0 NA HA NA NA 79.0

8% 74.0 73.5 75.5 75.5 NA NA NA NA 75.3

1Or)r, 74.8 74.0 74.0 74.0 NA NA NA NA 73.3

1250 72.5 72.0 70.8 70.5 NA NA NA HA 70.3

1600 70.8 70.8 67.5 67.8 NA HA NA NA 6-.,-_..'

.._v?r_r'r_68.5 69.0 68.0 67.B NA NA NA NA b:._=

2500 65.0 66.0 63.5 64.0 NA NA NA NA 64.0

3150 62.0 62.3 63.5 63.5 NA NA NA NA 63.3

4000 63.8 63.5 64.3 64.3 NA HA NA HA 64.0

5000 64.3 63.8 64.5 64.5 HA NA NA NA 64.0

..................................................................................

NANotAvailable

-186-
TABLE F.3 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS,FLIGH14T

CABINMICROPHONENUMBE3R

Band One-ThirdOctaveBandBoundPressureLevel, dBre 20 microPa

Center ..................................................................................

Frequency TestCondition

Hz IO II 12 13 14 15 16 17 18

25 92,0 83.5 90.5 93.3 NA NA NA 96.5 95.0

32 76.0 68.0 73,0 75.8 NA NA NA 82.5 78.3

40 66.8 64.5 65.5 63.5 NA NA NA 65.8 64.5

50 83.8 75.0 77.8 74.8 NA NA NA 75.8 75.8

63 8%0 84.8 89.8 83.8 NA NA NA 84.8 79.3

80 102.8 97.5 103.5 96.8 NA NA NA g8.8 93.5

100 87.0 82.0 86.3 82.0 NA NA NA 83.3 82.5

125 85.8 83.8 86.0 84.0 NA NA NA 83.5 83.0

160 93.3 93.0 94.0 96.3 NA NA NA 95.8 94.5

200 85.5 84.5 80.0 81.5 NA NA NA 81.8 81.0

250 92.3 BB.3 83.5 85.3 NA NA NA 87.0 84.8

315 86.5 82.5 79.5 81.3 NA NA NA 82.0 82.0

400 81.8 76.8 75.5 81.8 NA NA NA 80.3 81.3

500 80.8 76.0 73.8 84.3 NA NA NA 83.3 88.3

b30 76.8 73.8 70.5 73.3 NA NA NA 73.3 77.0

800 75.5 7D.3 68.8 7_).8 NA N_ NA 72.0 73.8

lOOO 73.8 69.8 69.0 68.8 NA NA NA 69.3 70.0

1250 70.8 66.8 66.3 67.0 NA NA NA 66.8 67.0

1600 68.0 64.0 63.0 63.5 NA N_ NA 64.0 64.3

2000 67.8 65.0 63.8 63.8 NA NA NA 64.5 64.0

25(<! 64.0 61.5 60.5 61.0 NA NA NA 61.5 61.5

3150 64.0 61.5 61.3 61.0 NA NA NA 61.5 61.5

4000 64.3 62.8 6_,o_ 62.8 NA NA NA 62.8 _._.5

5000 64.3 64.0 63.8 63.0 NA NA NA 63.5 62.5

NANotAvailable

-187-
TABLE F. 4

ONE-THIRDOCTAVBAND E SOUNDPRESSURELEVELS.FLIBHT14

CABINMICROPHONE NUMBER4

Band One-ThirdOctaveBandSoundPressureLevel, dBre 20=icro Pa

Center ..................................................................................

Frequency TestCondition

Hz I 2 3 4 5 6 7 B 9

25 95.0 94,8 99.5 99.8 NA NA NA NA 99.8

32 BI.5 79.B B2.B 86.5 NA NA NA NA B6.B

40 6B.B 69.0 69.0 70.0 NA NA NA NA 69.5

50 77.0 78.3 79.3 79.5 NA NA NA NA 7B.B

63 94.8 97.0 98.3 9B.0 NA NA NA NA 97.0

BO iJI.8 lll.B 113.0 114.3 NA NA NA NA 113.5

tO0 92.5 Bg.B 91.5 94.0 NA NA NA NA 93.5

125 85.3 86.3 88.0 87.5 NA NA NA NA 86.0

160 93.0 94.3 99.8 99.5 NA NA NA NA 99.3

200 80.5 80.3 84.3 83.5 NA NA NA NA 83.5

250 B3.3 84.0 B2.3 BI.B NA NA NA NA BO,B

315 80.8 79.0 82.5 83.3 NA NA NA NA 82.5

400 77.3 76.5 79.0 80.B NA NA NA NA 7B.B

500 76.3 76.3 SO.3 80.5 NA NA NA NA 80.0

63!) 77.0 76.8 80.0 81.0 NA NA NA NA BO.B

BOO 74.8 74.5 77.8 77.3 NA NA NA NA 77.5

I000 74.5 74.5 74.8 75.3 NA NA NA NA 74.5

1250 74.B 74.5 71.8 71.B NA NA NA NA 71.0

1600 70.0 70.8 66.8 67.0 NA NA NA NA 67.0

2000 67.0 67.0 64.3 64.8 NA NA NA NA 64.B

2500 63.B 64.0 61.0 61.0 NA NA NA NA 60.B

3150 59.0 60.0 60.5 61.0 NA NA NA NA 60.3

4000 5B.3 60.0 60.0 60.0 NA NA NA NA 60.0

5000 57.B 60.0 60.0 60.0 NA NA NA NA 60.0

..................................................................................

NA NotAvailable

-188-
TABLE F.4 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLI6HT14

CABINMICROPHONE NUMBER4

• Band One-ThirOdctaveBandSoundPressureLevel,dBre20microPa

Center ......................................................................

Frequency TestCondit i on

• Hz 10 11 12 13 14 15 16 17 18

25 99.5 91.0 97.5 100.5 NA NA HA 103.8 I0_._

32 83.5 75.0 80.8 82.8 HA HA NA 90.0 85.5

40 68.8 66.0 68.0 66.5 HA HA HA 70.3 67.8

50 78.5 74.5 76.0 74.0 HA NA NA 73.5 71.8

63 97.8 95.5 96.3 94.3 NA NA NA 93.0 90.5

80 112.5 109.0 110.5 I07.B HA NA NA I08.0 105.5

100 91.3 8_.3 88.3 85.5 NA HA NA 86.8 85.3

125 87.5 Bl.B 85.0 81.0 NA NA NA 81.3 81.5

160 98.5 86.0 96.0 91.8 NA NA NA 93.B 93.5

200 B2.5 77.5 76.8 76.5 HA HA HA 77.0 78.5

250 82.0 75.0 69.5 75.5 NA NA NA 77.B 76.5

315 81.5 74.8 74.3 73.3 NA NA NA 74.5 76.0

400 SO.0 77.B 75.3 76.B HA NA NA 77.0 78.0

500 S'J.3 7b.5 73.8 75.5 NA NA NA 75.5 76.5

630 8:J.8 79.f. 71.B 76.5 NA NA NA 78.0 75.8

BOO 7B.3 72.3 69.3 70.0 NA NA NA 72.0 71.5

I000 75.3 69.5 68.5 67.5 NA NA HA 69.0 68.5

1250 71.8 /,5.0 63.8 /`4.5 NA NA NA /`5.5 65.5

I/`00 67.8 60.3 /,0.0 /,0.8 NA NA NA /,2.0 61.5

2000 65.3 58.3 60.0 58.B NA HA NA /`0.0 59.5

2500 /,1.3 56.0 60=0 57.8 NA NA NA 56.8 56.8

3150 /`0.5 55.8 60.0 55.0 NA NA NA 56.0 55.5

4000 60,0 55.0 60.0 55.5 HA HA NA 56.3 55.B

5000 60.0 5/,.5 /,0.0 56.0 NA NA NA 56.5 5/,.3

NA NotAvailable

-189-
TABLE F. 5

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT14

CABINffICROPHONE NUMBER5

Band One-ThirOcta d veBandSoundPressurLeevel,dBre20microPa "

Center .......................................................................

Frequency TestCondition

Hz I 2 3 4 5 6 7 8 9 "

.............................................................................................

25 95.5 95.3 IO0.O 100.3 NA NA NA NA 100.8

32 82.0 79.5 83.0 87.0 NA NA NA NA 87.0

40 68.5 68,8 6%3 70.0 NA NA NA NA 69.5

50 75.3 76.5 79.0 78,8 NA NA NA NA 78.3

63 94.3 95.3 98.0 97.8 NA NA NA NA 96.8

80 109.3 110.5 113.0 113.0 NA NA NA NA 112.8

I00 89.0 89.3 92.0 92.8 NA NA NA NA 92.5

125 85,3 86.3 88.0 86.8 NA NA NA NA 86.8

160 100.3 98.5 100.0 I01.0 NA NA NA NA 101.8

200 83.8 83.0 85,0 85.3 NA NA NA NA 85.5

250 87.3 85.5 79.3 82.0 NA NA NA NA 81.8

315 81.0 80.3 83.3 83.3 NA NA NA NA 84.3

400 7B.B 78.0 B2.B 86.3 NA NA NA NA BT.B

500 76.{! 75.8 80.5 BO.B NA NA NA NA 80.5

630 77.5 77.5 79.8 80.0 NA NA NA NA 79.8

800 75.0 75.5 77.5 77.5 NA NA NA NA 77.5

1000 75.3 74.8 74.3 74.8 NA NA NA NA 74.5

1250 75.3 75.0 71.5 71,8 NA NA NA NA 71.0

1600 71.3 70.8 67.3 67.5 NA NA NA NA 67.0

2000 6B.B 67.8 65.0 64.8 NA NA NA NA 64.5

2500 66.5 66.3 60.8 61.5 NA NA NA NA 61.5

3150 59.0 58.0 60.0 60.0 NA NA NA NA 60.0

4000 59.3 58.8 60.0 60.3 NA NA NA NA 60.0

501"0 59.3 58.5 60.3 60.3 NA NA NA NA 60.0

NA NotAvailable

-190-
TABLE F.5 (CONTINUED)

ONE-TH!RODCTAVEBANDSOUNDPRESSURELEVELS.FLIGH14T

CABINMICROPHONENUMBER5

Band One-ThirdOctaveBandSoundPressureLevel, dBre 20 microPa

Center ..................................................................................

Frequency TestCondition

Hz 10 11 12 13 14 15 16 17 18

--.................................................................................

25 100.0 91.5 98.3 101.3 NA NA NA I04.5 102.8

32 83.5 75.8 81.0 83.3 NA NA HA 90.0 85.8

40 69.0 66.0 67.8 67,5 NA NA NA 70.5 68.0

50 78.3 75.0 75.8 74.8 NA NA HA 73,3 72,5

63 98.0 95.8 96.0 95.0 NA HA NA 93.0 91,5

80 113.3 109.3 II0.3 109.0 NA NA NA 107.5 107.0

100 92.3 86.5 88.0 86.3 NA NA NA B6.5 86.5

125 87.8 83.8 84.3 83.8 NA NA HA 83.5 81.5

160 100.3 95.3 9a.3 96.5 NA NA NA 97.3 95.5

200 84=3 80.5 78.5 80,8 HA NA HA 81.3 81.0

=,_?_n 83.8 79.5 79.8 80.8 NA NA NA 82.3 B=.on _

315 85.0 76.8 77.0 80.3 NA NA NA 82.8 B2.0

400 82.8 75.8 78.8 78.0 NA NA NA 79.5 79.0

500 80,5 75.8 75.3 74.0 NA NA NA 76.5 75.8

630 79.8 76.0 72.3 77.3 HA NA NA 78.3 76.0

800 79._ 71.5 70.0 70.8 HA NA HA _=.n 7,._

1000 75.C 68.5 67.0 67.8 NA NA NA 68.5 68.5

1250 71.3 64.8 64.5 65.5 HA NA NA 66.5 66.0

1600 67.B 60.5 60.3 61.8 HA NA NA 63.0 63.0

2000 65.3 59.5 60.0 60.0 NA NA NA 60.5 61.3

2500 61.5 56.3 60.0 56.0 NA NA NA 56.5 56.5

3150 60.5 56.0 60.0 55.8 NA NA NA 56.3 56.0

4000 bO.O 57.0 60.0 56.8 NA NA NA 57.0 57.0

5000 60,0 58.5 60.0 57.8 HA NA NA 57.8 58.0

..................................................................................

NA NotAvailable

-191-
TABLE F.6

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT14

CABINMICROPHONENUMBER6

Band One-ThirdOctaveBandSoundPressureLevel,dBre20microPa

Center ......................................................................

Frequency TestCondition

Hz 1 2 3 4 5 6 7 B 9

25 86.5 86.5 90.0 91.0 NA NA NA NA QI.(

32 73.3 70.B 73.5 77.3 NA NA NA NA 77.5

40 69.8 69.8 67.0 66.5 NA NA NA NA 65.0

50 82.5 81.5 82.5 83.5 NA NA NA NA 82.3

63 B5.3 85.3 86.5 86.0 NA NA NA NA 85.0

BO 100.3 101.3 102.5 101.5 NA NA NA NA lO0.B

I00 83.0 83.8 84.8 B4.B NA NA NA NA 84.0

125 89.0 91.0 91.8 90.5 NA NA NA NA 90.8

160 ICJ._ _ _ 105.0 106.3 107.3 NA NA NA NA 107.3

200 Bg.B 90.8 89.3 89.5 NA NA NA NA BB.8

250 97.5 96.3 93.0 94.5 NA NA NA NA 92.0

315 88.0 86.5 85.5 90.0 NA NA NA NA 89.0

400 77.5 77.0 85.5 BB.8 NA NA HA NA BB.5

500 77.0 76.8 8!.0 84.0 NA NA NA NA 86.3

_30 73.8 74.0 77.3 77.0 NA NA NA NA 77.0

BOO 74.0 73.0 75.3 75.5 NA NA NA NA 75.0

I000 74.3 73.0 73.8 73.8 NA NA HA HA 73.5

1250 74.5 73.3 69.8 70.5 NA NA NA NA 69.0

1600 71.3 71.3 b7.0 67.5 NA HA NA NA 66.0

2000 69.3 70.0 65.0 65.3 NA NA NA NA 65.0

2500 a4.B 64.5 62.8 62.5 NA HA NA NA 62.5

3150 59.3 59.3 60.8 61.0 NA NA NA NA 61.0

4000 59.0 5B.B 60.0 61.3 HA NA NA NA 60.B

5000 59.0 58.5 60.0 60.3 NA NA NA NA 60.0

..................................................................................

NA NotAvailable

-192-
TABLE F.6 (CONTINUED)

ONE-THIRDOCTAVBEANDSDUNPRESSUR D LEVE ELS, FLIGHT14

CABINMICROPHONUMNEBE6R

Band : One-ThirdOctaveBandSoundPressureLevel, dBre 20microPa

Center :.......................................................................

Frequency: TestCondition

Hz : 10 11 12 13 14 15 16 17 18

25 Z 90,5 82.3 88.8 92.3 NA NA NA 95.5 93.5

32 _ 74.0 67.0 72.0 74.8 NA NA NA 81.5 77.3

40 : 65.8 63.8 64.0 63.0 NA NA NA 64.5 63.5

50 i 81.5 73.3 76.8 72,0 NA NA NA 75.3 73.0

63 : 85.3 82.5 84.8 83.8 NA NA NA 81.0 79.8

80 : 101.0 g5.8 98.5 97.8 NA NA NA 94.8 95.0

100 % 84.0 80.3 80.5 79.5 NA NA NA 78.5 79.5

125 : 92.3 86.0 90.0 88.0 NA NA NA 87.0 88.0

160 # 106.8 97.5 103.5 101.3 NA NA NA 103.0 102.5

200 _ 88.3 81.0 83.3 84.0 NA NA NA B4.B 84.8

250 : gO.5 81.3 86.3 88.0 NA NA NA 88.8 88.5

315 _ 85.5 76.8 83.8 82.0 NA NA NA 86.5 82.5

400 : 86.0 76.3 Bl.O 83.0 NA NA NA 85.8 84.3

500 I 82.8 75.3 78.9 80.8 NA NA HA 79.5 83.5

130 : 77.0 71.5 69.8 73.5 HA NA NA 75.0 74.0

800 I 75.5 69.0 67,8 69.0 HA NA HA 70.0 70.0

1000 : 74.0 68.0 67.3 67.0 NA NA NA 68.0 67.8

1250 = 70,0 64,5 63.0 63,8 NA NA NA 64.3 64.5

i_00 I 67.0 61.5 b0.8 61.0 NA NA NA 62.0 61.5

2000 : 65.8 61.0 60,3 59.5 NA NA HA 61.0 60.0

2500 % 62.8 58.0 57.8 57.3 NA NA NA _7wBl_n EuS.0

3150 I 61.3 56.8 56.3 56.5 NA HA NA 57.8 57.0

4000 : 60.8 57.0 56.8 56.8 NA NA NA 57.3 57.0

5000 _ 60.5 57.0 57.0 56.3 NA NA NA 56.8 56.5

NA NotAvailable

-193-
-194-
APPENDIX G

Effect of Cabin Pressurizationon Cabin Sound Pressure Levels

(Harmonicsand One-ThirdOctave Bands).

-195-
TABLE G. 1

CABINMICROPHONENUMBER3 : EFFECTOFPRESSURIZATION

?.... .....Tiiiii-T..................... ..................

ConditionINumberI I 2 3 4 5 6 7 B 9 10

_STAIBOARD ENGINECOMPONENTS

_Cond3- Cond213 _ %6 -5.2 -3.5 3,3 2,5 18,7 -2.5

ICond4-Condl] 3 ] 6.7 -1.2 -5.5 -10,9 5,1 0.9 "

:Cond3- Cond2] 4 ] -4.7 4.7 -3.4 6.5 11.5 3.6 7.2 3.3

=Cond4-Condl_ 4 _ 6.0 -0.1 -3.6 11.0 5.8 7.4 4.4 5.1

..............................................................................................

_PORTENGINECOMPONENTS

=Cond3-Cond21 3 -4.5 B.5 0.I II.I 3.B -2.9

_Cond4-Condl_ 3 -12.4 -7,B 4.4 3.6 3.2 10.9 I.I

ICond3- Cond2I 4 -I.I -7.B O.B 12.B 5.7 5,6

ICond4- Cond!= 4 -0.7 -2.7 3.B 8.7 13.0 9.3 2.0 2.6

CABINMICROPHONENUMBER6 : EFFECTOFPRESSURIZATION

Test I Flight_ HarmonicLevel,dBre20microFa

ConditionI Number_ 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 !0.0

ISTARBOARD ENGINECOMPONENTS

=Cond3-Cond2= 3 _ -O.B 3.4 -12.1 I0,7 -3.2

ICond4- Cond1: 3 : 0.2 6.8 -6.9 -3.3 7.8 4.2

ICond3- Con!2f 4 _ 0.4 5.0 -0.7 2.3 18.5 2.4 7.8 2.3

:Cond4-Condll 4 _ 0.4 1.6 2.8 5,9 14.5 7.5 3.3 l.B

IPOGTENGINECOMPONENTS

_Cond3-Cond21 3 0.7 -1.7 -4.3 -8.4 7.5 4.2 3.1

=Cond4-Condl_ 3 2,2 0,2 -2.0 6.7 6.8 12.3 3.2

ICond3-Cond2= 4 2.2 0.3 -3.4 -1.7 18.6 4.5 4.9

ICond4-Condl= 4 2.4 0.7 -2.7 1.5 21.0 11.I 10.9 14.3 2.1

-196-
TABLE G. 2

ONE-THIRDOCTAVEBANDSOUNDPRESSURE LEVELSFLIGHTS . 3 AND4.

EFFECTOFPRESSURIZATION

Changein SoundLevel,dO

One-lhird ..................................................................................

Octave CabinMicrophoneNo3 CabinMicrophoneNo6

Band Flight t3 Flight 14 Flight 13 Flight 14

Center ...........................................................................

Frequency Cond3 Cond4 Cond3 Cond4 Cond3 Cond4 Cond3 Cond4

Hz -Cond2 -Cond1 -Cond2 -Cond1 -Cond2 -Cond1 -Cond2 -Cond!

25 2.0 0.5 3.8 4.3 3.0 2.5 3.5 4.5

32 -4.0 -3.5 3.5 3.5 -6.0 -4.3 2.7 4.0

40 -3.7 -3.0 -2.5 -2.5 -3.0 -l.B -2.B -3.3

50 -2.5 -1.5 0.7 1.2 O.O 1.8 l.O 1.0

63 -3.2 -2.8 -1.2 -0.2 0.3 1.8 1.2 0.7

80 -3.3 -4.5 -1.5 -0.8 0.0 2.0 1.2 1.2

100 0.5 -2.0 1.0 -0.2 0.3 2.0 1.0 I.B

125 2.3 O.B 0.7 1.2 -0.3 0.3 O.B 1.5

160 2.0 -1.5 -1.5 -I.0 1.8 1.5 1.3 l.B

200 -1.7 -3.0 -1.2 -1.5 -I.8 -3.0 -1.5 -0.3

250 -1.3 -0.3 -2.0 -0.7 -6.3 -2.5 -3.3 -3.0

315 0.7 -1.5 6.3 6.5 -I.0 1.5 -1.0 2.0

400 1.8 3.5 6.2 6.0 2.3 3.8 B.5 11.3

500 5.2 5.0 3.5 4.5 3.3 3.3 4.2 7.0

630 2.3 0.7 2.7 3.5 1.5 2.3 3.3 3.2

800 1.5 1.7 2.0 1.5 2.0 2.3 2.3 1.5

IO00 1.5 2.5 O.O -0.8 1.5 t.B O.B -0.5

1250 0.5 O.B -1.2 -2.0 -0.5 0.8 -3.5 -4.0

1600 -0.7 0.3 -3.3 -3.0 -1.3 0.5 -1,.3 -3.B

2000 -1.2 0.2 -I.0 -0.7 -O.B -0.5 -5.0 -4.0

2500 -0.5 O.5 -2.5 -1.0 -1.3 0.0 -1.7 -2.3

3150 1.7 2.5 1.2 1.5 1.3 2.3 1.5 1.7

4000 1.5 2.3 0.8 0.5 1.5 2.3 1.2 2.3

5000 2.0 2.2 0.7 0.2 1.5 2.3 1.5 1.3

-197-
-198-
APPENDIX H

Noise Reduction for UntreatedCabin (Differencebetween Exterior

and InteriorHarmonics and One-Third Octave Band Sound Pressure

Levels).

-199-
TABLE H. 1

NOISEREDUCTIONEXT: ERIOSTRARBOARD MICSPL- CABINMIC_3SPL

(STARBOAPROPELLE RD CORMPONENT)

Test : Flight i RPM _BPF = HarmonicLevel dBre 20,icro Pa

Condition: Number: : Hz = 1 2 3 4 5 6 7 B 9 10 "

1 Flight 1520.0 76.0 37,8 2B.B 21.2 2B.6 25.2 3I.B

2 3 1572.5 7B.6 43.0 31.4 2&.O 29.4 26.4 40.1 37.3

3 1570.0 7B.5 32.5 3_.7 29.1 30.1 29.3 24.3 34.0 27.3

"t't 4 1520.0 76.0 30.1 29.4 26.! 40.3 23.1 o,.1 32.7

9 1520.0 76.0 27.7 2B.6 2B.4 3B.3 30.5 34.9

: 10 1572.5 7B.6 26.7 29.0 30.2 33.7 37,4 30.6 25,9

11 1515.075.B 2B.B 32.3 30.1 33.6 30.1 27.0 30.0 2B.6 32.0 29.7

17 1517.575.9 30.6 34,5 41.2 40.4 32.0 1B.4 26.2 35.9 36.7

IB 1570.07B.5 27.0 32.4 3&.9 42.1 32.2 23.5 23.1 23.9 28.3 2B.5

TABLE H o2

NOISEREDUCTION: EXTERIORPORTMICROPHONESPL- CABINMIC16SPL

(PORTPROPELLERCOMPONENT)

Test :FlightI RPM IBPF : HarmonicLevel,dBre20microPa

IConditio_nNumberI I Hz i I 2 3 4 5 6 7 B 9 10

I 1 Flight 1572.5 7B.6 21.7 31.B 39.4 40.3 34.4 46.4 39.5

2 3 1525.0 76.3 26.4 34.6 41.B 37.6 41.7 40.2 35.4

: 3 1525.0 76.3 24.7 34.B 44.5 44.2 32.2 33.9 30.4 32.6

I 4 1572.57B.& IB.B 31.2 40.0 31,B 26.6 32.B 35.3 35.6

I 9 1572.5 7B.6 19.3 27.4 3B.B 33.3 26.9 35.9 35.2 34.4 33.9

10 1525.0 76.3 26.4 31.5 43.6 33.1 30.7 3B.4 34.3

: 12 1520.0 76.0 2B.3 3B.B 40.0 30.4 26.6 2B.3 32.1 23.6 21.9 26.0

l 17 1570,0 7B.5 21,7 30,B 3B.9 35.7 31.3 30.1 32.1 34,5 31.9

: 1B 1520.0 76.0 27.4 30.4 37.5 35.4 33.7 24.0 29.2 34.9

........................ _ ............................. _ ...................................................

-200-
TABLE H° 3

ONE-THIRDOCTAVEBANDSOUNDPRESSURE LEVELSFLIGHT . 13

EXTERIOSTRARBOAMRDICROPHON - CEABINMICROPH1O3NE

Band Changien One-ThirdOctaveBandSoundPressureLevelt dB

Center ..................................................................................

Frequency TestCondition

Hz I 2 3 4 5 6 7 B 9

25 32.5 32.5 24.7 26.8 21.5 23.0 25.5 25.5 22.7

32 33.7 35.3 33.0 32.5 31,5 32.2 34.3 27,5 30,8

40 42.2 42.3 40.5 40.5 40.0 39.5 40.5 32.6 40.5

50 29.5 31.8 28.9 26.0 29.0 28.0 29.8 27.7 28.2

63 27.0 24.5 25.2 28.3 26.8 21.5 25.7 30.3 26.7

80 22.8 25.2 27.5 26.3 28.0 21.0 26.5 34.3 27.2

100 25.0 29.8 26.3 24.0 24.5 22.3 24.0 24.2 24.0

125 28.3 28.8 23.5 25.7 24.2 22.0 26.0 22.3 24.5

160 28.0 30.2 27.7 29.0 25.2 22.2 31.0 21.2 25.7

200 23.0 24.5 23.2 23.7 27.3 24.8 24.7 24.0 24.5

250 21.7 23.7 24.3 20.5 31.8 25.3 26.0 25.2 22.2

315 28.0 29.0 27.8 29.2 28.7 27.2 26.5 29.0 28.2

400 28.7 30.8 26.5 23.5 24.0 25.2 26.0 25.0 24.8

500 30.0 32.0 22.8 22.3 22.0 23.5 22.8 22.5 22.7

630 26.5 29.0 22.0 22.3 21.2 19.2 19.0 20.5 20.7

800 29.2 31.2 24.7 24.0 23.0 23.3 23.0 23.0 23.3

1000 31.5 33.0 26.0 25.3 24.0 23.7 24.0 24.3 24.0

1250 33.3 34.5 29.0 28.7 27.8 27.2 27.5 27.2 26.7

1600 34.8 35.3 31.7 30.5 29.5 29.3 29.3 29.3 29.0

2000 36.7 37.3 34.2 33.0 31.8 31.0 31.2 31.5 31.3

2500 39.0 39.5 35.7 35.3 33.7 33.8 33.5 33.7 33.3

3150 42.7 43.5 38.0 37.2 35.5 36.2 35.5 36.0 35.2

4000 42.3 43.3 38.8 3B.0 37.3 38.0 36.B 37.5 36.7

5000 42.2 44.0 38.5 38.8 36.8 37.7 37.0 38.3 37.5

-201-
TABLE H.3 (CONTINUED)

ONE-THIRDOCTAVBEANDS0UNDPRESSURE LEVELS, FLIGHT13

EXTERIOSRTARBOARDMICROPHO-NECABINNICROPHONE13

Band Changien One-ThirdOctaveBandSoundPressureLevetl dB

Center ..................................................................................

Frequency TestCondition

Hz I0 11 12 13 14 15 16 17 18

25 24.5 27.5 19.3 13,3 22.7 14,5 15.5 12.7 15.5

32 32.2 29.3 28.0 26.5 26.5 27.5 27.0 25.2 28.0

40 39.5 48.5 37.0 36.5 36.7 35.8 36.5 36.0 36.3

50 28.7 28.5 25.0 29.2 29.2 28.3 28.5 27.5 28.3

63 23.3 27.8 15.3 28.0 28.0 22.2 26.5 27.8 22.2

80 24.7 28.0 9.5 28.8 29.0 22,0 26.8 27.0 24.3

I00 25.5 24.2 21.5 24.3 23.5 22,5 23.7 23,3 23.7

125 22.5 27.5 18.8 25.8 25.7 23.8 27.2 27.2 23.5

160 24.5 32.5 10.7 28.0 28.7 24.5 32.5 28.0 28.0

200 24.2 29.5 23.3 30.7 28.7 28.2 2%5 30.5 27.8

250 27.3 30.3 19.5 36.2 32.5 31,7 32.5 35.B 34.0

315 28.3 31.3 26,3 33.5 29.7 30.5 32.3 31.5 33.0

400 26.7 27.8 24.0 26.0 26.0 26.5 27.5 24.5 29.3

500 23.0 23.8 22.7 19.0 19.5 19.2 19.8 17.0 21.5

630 20.5 20.5 20,5 20.0 20.5 21.0 21.7 21.5 21.0

800 23.5 24.0 24.7 22.5 22.5 22.3 21.8 22.5 23.7

1000 24.0 26.0 26.5 23.5 23.8 23.7 23.8 23.2 24.7

1250 27.0 29.5 30.2 24.5 24.2 23.5 24.0 24.3 24.7

1600 29.8 31.2 31,7 26.2 25.8 26.0 26.5 26.7 27.3

2000 31.5 33.3 31.7 29.8 30.5 29.7 29.5 30.7 31.0

2500 33.8 33.5 34.5 31.5 33.0 32.3 32.5 32.2 32.5

3150 35.5 36.8 36.5 34.0 35.8 34.5 33.5 3q.3 34.3

4000 36.7 37.7 38.0 35.3 36.5 35.8 34.8 35.2 34.7

5000 37.2 37.5 36.3 35.0 36,8 35.8 34.5 35.0 35.8

-202-
TABLE H. 4

ONE-THIRDOCTAVEBANDSOUNDPRESSURE LEVELSF.LIEHT13

EXTERIORPORTMICROPHONE - CABINMICROPHON16E

Band Changein One-ThirdOctaveBandSoundPressureLevel, dB

Center ..................................................................................

Frequency TestCondition

Hz 1 2 3 4 5 6 7 B 9

25 15.6 14.3 9,0 11.0 5,8 5.8 6.0 7.8 5.5

32 15.6 15.3 1B.5 16.8 15.8 15.6 16.3 16.3 15.3

40 30.5 30.3 30.8 30.3 30.0 29.B 30.0 30.1 29.8

50 33.5 33.3 31.3 29.8 30.0 30.3 2B.I 29.3 29.6

63 21.5 24.B 23.B 19.3 24.B 32.0 21.5 22.B 19.3

80 21.3 23.3 22.B 19.0 24.6 32.8 21.0 23.0 19.0

100 23.3 24.3 22.3 20.3 23.5 25.B 21.5 22.5 20.3

125 27.8 29.1 27.5 25.8 25.8 31.1 27.1 25.B 25.3

160 31.1 30.6 27.8 2B.B 26.0 38.6 28.3 26.8 27.0

200 29.3 30.5 30.B 31.5 31.6 33.8 32.8 31.3 29.B

250 35.8 33.B 38.3 37.3 42.3 40.3 41.B 39.6 37.B

315 32.0 31.1 30.3 29.5 29.B 31.0 31.B 30.3 31.B

400 2B,5 27,B 23.5 23,3 25.5 26,3 25.B 25,3 25.6

500 2B.5 27.B 22.3 24.3 23.6 23.3 23.B 23.6 25.3

630 23.3 22.3 18.5 19.5 19.5 20.0 19.6 20.1 20.3

800 24.6 24.6 20,1 20.8 20.1 20.3 20.3 19.5 20.6

1000 25.3 26.I 22.3 21.B 20.8 20,8 21.0 20.8 20.6

1250 26.0 2b.8 25.0 23.8 23.5 23.3 22.8 23.8 23.3

1600 29.0 2B.B 28.0 27.3 26.3 25.B 25.3 26.0 25.8

2000 31.3 31.B 30.B 30.B 29.5 2B.B 2B.5 2B.B 2B.B

2500 34.5 35.I 34.3 33.5 32.1 32,3 31.8 31.5 31.8

3150 39.3 39.5 36.6 36.6 35.6 35.3 35.1 35.0 36.0

4000 41,5 42.0 39.3 39.1 3B.O 37.B 37.3 37.B 38.I

5000 42.6 43.3 41.1 40.0 39.5 40.3 38.5 39.5 39.3

-203-
TABLE H.4 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURLEVELS. E FLIGHT13

EXTERIORPORTH]CROPHONE - CABINNICROPHD16NE

Band Changein One-ThirdOctaveBandSoundPressureLeve], dB

Center ..................................................................................

Frequency TestCondition

Hz 10 11 12 13 14 15 16 17 18

I

25 6.8 10.5 6.8 -2.0 -1.7 -O.B 0.8 -2.2 0.5

32 15.5 II,0 12.5 10.8 9.5 11.0 12.3 9.5 12.0

40 29.8 26.8 26.6 25.8 26.0 25.3 25.8 25.6 25.8

50 29.6 27.8 31.8 31.3 34.0 31.5 30.8 30.8 30.6

63 24.3 14.3 29.6 27.6 33.8 24.8 25.3 22.5 26.3

80 22.6 10.3 29.5 27.5 34.5 24.3 25.3 22.8 24.3

I00 21.6 19.0 24.8 23.8 23.3 21.8 23.3 22.6 21.6

125 28.3 19,5 31.3 29.3 22.5 25.6 29.8 24.1 27.1

160 31.1 13.0 37,3 35.0 21.8 26.1 33.5 27.5 27.8

200 30.9 23.6 35,3 29.1 29.3 30.5 30.8 28,1 29.0

250 37.9 24.6 38.0 35.5 40.3 40.1 41.3 36.8 30.8

315 29.8 20.3 29.3 30.0 32.8 32.3 30.8 33.6 31.8

400 25.8 19.8 25.0 24.6 26.5 26.5 27.1 27.5 25.1

500 23.3 21.0 23.5 21.8 24.8 23,6 24.8 25,0 22.6

630 19.3 19.8 21.3 17.8 19.6 19.3 19.8 19.8 17.3

800 19.6 22.3 23,6 21.8 22.3 22.3 22.1 23.3 20.3

I000 21,3 23,5 25.3 23.3 23,0 23,5 23.0 24,2 23.0

1250 22.8 27.6 27.3 23.8 23.8 24.3 23.8 24.5 24.1

1600 26.5 30.8 30.6 25.8 26.1 26.0 25.5 26.0 26.0

2000 29.0 32.3 32.1 30.1 31.0 31.5 30.3 30.3 30.5

2500 32.3 35,I 35.0 33,3 33,8 33,5 32,6 33,8 33.5

3150 34.3 37.6 37.1 35.8 36.1 35.8 35.3 36,0 35.6

4000 37.0 40.3 38.8 37.3 38.3 37.8 36.8 37.1 37.8

5000 40.1 41.3 3B.5 39.1 39.8 39.3 38.8 38.5 39.1

-204-
APPENDIX I

Noise Reduction for Treated Cabin (DifferenceBetween Exterior and

Interior Harmonics and One-ThirdOctave Band Sound Pressure

Levels).

-205- !
TABLE I. 1

NOISEREDUCTION: EXTERIOSRTARBOARDM!CSPL- CABINM!C13SPL

(STARBOARD PROPELLERCOMPONENTI

Test I FlightI RPM IBPF I HarmonicLevel,dBre20microPa

ConditionI NumberI I Hz I I 2 3 4 5 6 7 9 9 I0

1 Flight 1520.0 76.0 38.9 34.3 27.8 45.6 38.3 47.9 43.0 49.3

2 4 1570.0 79.5 44.8 40,0 26.8 36.9 37.8 49.1 56.2 54.8

3 1572.578.6 49,0 35.& 3!.9 34.9 33.1 35.4 40.3 39,7 38,9 "

4 1517.575.9 31,8 33,4 31.1 34.? 33.8 41.6 37,3 41,3

9 !530.076.5 28.6 31.5 30.1 35.1 37.1 34.9 35.6 44.6

10 1572.5 79,6 36,7 39,B 32.4 36,8 37.0 37,1 39,4 40.6 37.1

!I 15!5.0 75.8 31.0 31.8 32.9 35,1 38.8 33.0 40.6 40.2 40.2 39.6

17 1517.5 75,9 28,0 31.4 37.9 39.9 44.5 27.9 48.3 44.2 42,5 35.4

IB 1572.5 78.6 35,5 34.6 42.2 40.0 42.6 27.4 44.3 36.2 37.0 39.8

TABLE I. 2

NOISEREDUCTION: EXTERIORPORTMICROPHONESPL- CABINM!C16SPL

(PORTPROPELLERCOMPONENT)

Test IFli_tI RPM I BPF _ HarmonicLevel,dBre20microPa

ConditionINumberI I Hz I I 2 3 4 5 6 7 8 9 I0

I Flight 1575.0I 78.8 36.9 27.4 33.6 38,4 55.9 49.0 57.7 61.8 46.6

2 4 1525.0I76.3 37.2 28.0 33.1 39.5 53.8 45.1 57.0 48.2

3 1527.5I76.4 33.3 26.4 34.B 39.2 33.3 39.2 4_.3 50.4

4 1572.5I79.6 33.1 25.4 34.7 34.1 32.7 35,3 44.5 45,3 42,9 51.0

9 1575.0I 7B.B 34.4 23.8 37.5 36.! 33.4 33.0 45.7 46.5 42.5 52.2

10 1527.5I76.4 33.9 25.5 37.5 38.9 3_.I 37.1 42.4 44,9 47.2

12 1520.0{76.0 30.7 23.B 36.1 35.1 33.7 29.4 39.5 40.9 42.4 39.7

17 1570.0I79.5 36.5 24.3 37.0 35.B 33.6 41.6 47.4 49.2 45.0 46,_

18 1517.5I75.9 36.6 24.6 34.7 38.5 35.2 37.7 40.0 54.2 44.3

-206-
TABLE I. 3

ONE-THIRDOCTAVBAND E SOUNDPRESSURE LEVELSFL, I6HT14

EXTERIOSTRARBOANICROPHONE RD - CABINNICROPHONE 13

Band Changein One-ThirdOctaveBandSoundPressureLevel, dB

Center ..................................................................................

Frequency TestCondition

Hz 1 2 3 4 5 6 7 8 9

25 19.0 19.5 ll.O 9.7 6.0

32 32.5 36.5 25.8 23.8 21.5

40 38.0 39.0 35.7 35.5 35.5

50 24.5 26.7 20.3 19.8 19.0

63 27.0 22.5 21.5 25.5 25.3

80 22.2 22.8 23.8 21.8 22.3

I00 25.0 39.3 25,0 21.5 21.5

125 31.2 31.7 27,8 27.8 27.3

160 28.0 32.7 34.2 28.0 30.3

200 30.0 31.5 30.2 29.5 29.8

250 28.5 28.7 30.7 28.5 2%7

315 41.0 39.8 33.0 33.3 32.7

400 40.7 42.2 33.8 32.7 32.8

500 43.0 43.7 36.5 35.5 32.0

630 43.5 45.7 38.3 36.5 35.0

800 45.0 47,8 40.0 40.0 38.5

1000 44.7 47.3 41.8 41.8 40.7

1250 46.5 48.8 45.2 45.0 43.2

1600 47,7 4%7 48.3 47.0 46.2

2000 50.0 50.8 47.9 47.2 45.8

2500 52.8 53.0 51.5 50.8 48.5

3150 54.8 56,2 50.0 51.0 49.0

4000 52.0 52.8 48.7 49.0 47.0

5000 49.5 52.0 47.5 46.5 45.8

-207-
TABLE 1.3 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURE LEVELSFLIGHT . 14

EXTERIORSTARBOARRDICROPHONE - CABINMICROPHONE 13

Band Changien One-ThirdOctaveBandSoundPressureLevelt dB

Center ..................................................................................

Frequency TestCondition

Hz 10 II 12 13 14 15 16 17 18

m

25 9.0 14.3 2.5 2.0 -2.7 -0.2

32 25.3 29.3 22.3 19.0 12.8 16.5

40 36.2 34.0 31.5 33.0 31.2 32.5

50 20.5 26".5 22.0 24.0 23.0 23.2

63 22.3 30.2 12.5 28.5 26.7 29.0

80 25.2 31.0 7.5 29.0 26.2 31.8

100 24.5 26.5 18.0 24.0 22.0 25.5

125 26.0 29.2 20.3 27.3 27.3 25.3

160 33.5 32.5 13.3 29.2 28.2 30.5

200 29.3 32.0 25.8 34.5 33.5 31.5

250 30.7 32.7 22.5 35.7 33,3 37.7

315 33.3 34.5 27.0 37.2 36.0 38.0

400 35.7 37.0 31.3 34,0 35.5 36.7

500 35.7 35.0 34.2 29.2 30.5 28.7

630 37.7 36.7 37.3 37.0 36.5 35.5

B00 39.5 39.5 39.7 36.5 35.B 36.7

1000 40.5 40.5 40.0 38.7 38.5 38.5

1250 44.0 42.5 43.0 39.8 40.0 40.8

1600 46.0 45.8 45.B 43.3 42.8 43.2

2000 46.0 43.8 45.0 42.5 42.3 43.3

2500 49.3 47.0 48.3 45.8 45.3 45.5

3150 48.3 47.0 47.5 45.3 44.8 45.0

4000 47.7 45.2 45.5 43.2 43.2 44.0

5000 47,0 41.8 43.0 42,0 41,3 42,5

..................................................................................

-208-
TABLE I. 4

ONE-THIRDOCTAVEBANDSOUNPRE D SSURLEEVELSFLI . BHT14

EXTERIORPORTMICROPHO-NECABINMICROPHONl&E

............................................................ ,,-..................................

Band Changien One-ThirdOttaveBandSoundPressureLevel, dB

Center ..................................................................................

Frequency TestCondition

Hz t 2 3 4 5 & 7 B 9

25 18.3 17.8 12.0 11.5 0.0 0.0 0.0 0.0 9.5

32 32.7 34,0 28.0 25.0 0,0 0.0 0,0 0.0 23.3

40 37.5 37.5 37.0 37,3 0,0 0.0 0.0 0.0 37.5

50 28,5 29.5 26.0 25.0 0,0 0,0 0.0 0.0 24.7

63 31,7 35.0 32.0 29.3 0.0 0.0 0.0 0.0 2%0

BO 34,0 33,0 30.0 31,0 0,0 0,0 0,0 0,0 31.0

100 34,5 32,2 2%0 30.5 0,0 0.0 0.0 0,0 30.0

125 29.5 2%5 26.2 25.5 0.0 0.0 0.0 0.0 24.0

160 28.5 28.5 25,7 24.7 0.0 0.0 0.0 0.0 24.5

200 32.5 33.2 32.7 30.5 0.0 0.0 0.0 0.0 30.7

250 33,B 33.5 35,3 35,0 0,0 0.0 0.0 0,0 37,0

315 39.3 39.5 3B.B 35.3 0.0 0.0 0.0 0.0 36.3

400 46.8 46.0 35.3 33.2 0.0 0.0 0.0 0.0 33.5

500 46,5 45.5 38.8 37.3 0.0 0.0 0.0 0.0 34.5

630 46.2 45.5 40.0 41.0 0,0 0.0 0.0 0.0 40,0

800 45.8 45,B 41.5 41.5 0,0 0.0 0.0 0.0 41.0

I000 44.7 46.5 43.0 43.0 0,0 0.0 0.0 0.0 41.8

1250 44.3 45.7 46.5 45.3 0.0 0,0 0.0 0.0 45.5

1600 47.5 47.5 49.0 48.5 0.0 0.0 0.0 0.0 48.5

2000 49.2 48.8 51.0 50.5 0.0 0.0 0.0 0.0 49.5

2500 53.2 53.5 52.7 53.3 0.0 0.0 0,0 0.0 51.5

3150 58.2 58.0 54.7 54.8 0.0 0.0 0.0 0.0 53.0

4000 58,5 58.2 55.8 54.2 0,0 0.0 0.0 0.0 53.2

5000 57.5 57.3 54.3 54.2 0.0 0.0 0.0 0.0 53.0

..................................................................................

NA NotAvailable

-209-
TABLE 1.4 (CONTINUED}

ONE-THIROCTAVE D BANDSOUNDPRESSURE LEVELS. FLIGHT14

EXTERIOPORT R HICRDPHONE - CABINHICROPHONE 16

]}and Changien One-ThirdOctaveBandSoundPressureLevel_ dB

Center ..................................................................................

Frequency Test Condition

Hz I0 11 12 13 14 15 16 17 18

25 10.3 11.7 7.0 1.5 -0.7 1,5

32 26.3 29.3 24.3 20.2 13,5 17.2

40 37,0 35.0 35,0 33,5 32,0 33,3

50 25.3 26.7 25.5 28.0 25.7 27.8

&3 32.7 20.3 30.7 29.0 28.5 32.7

80 31.0 15.5 31.0 28.5 31.7 30.5

100 28.3 25.0 28,8 27.0 30,5 27,3

125 25.2 21,0 24.0 24,0 23,5 24,5

1/,0 24.5 14.8 24.0 24.2 24.0 23.5

200 33.7 26.8 34.0 32.8 30.7 33.0

250 37.5 27.7 3&.7 34.3 37.0 35.0

315 37.5 32.0 35.5 36.3 35.0 37.0

400 35.5 33.5 34.0 33,0 33.2 33,2

500 37,2 35.2 33,7 33.2 38.8 32.0

630 39.8 39.0 40.0 37,5 39,5 38.3

800 40.5 42.5 42.5 41.5 43.3 40.5

I000 41.3 43.8 43.7 43.3 43.0 42.7

1250 44.3 47.5 47.3 46.0 46.7 4&,3

1600 47.8 50.5 50.0 48.B 48.5 49.0

2000 48.7 50.5 50.0 50.3 49.5 50.3

2500 51.2 53.5 52.0 52.2 52.5 52.5

3150 53.2 54.7 53.5 53.0 52.5 53.3

4000 53.5 54.0 53.0 53.0 53.2 53.0

5000 53.3 53.3 52.0 52.5 52.7 52.8

-210-
" APPENDIX J

InsertionLoss Provided by Treatment (Differencesin Harmonic and

One-ThirdOctave Band Sound PressureLevels for Flights 3 and 4;

No Adjustments for Changes in Exterior Sound Pressure Level).

-211-
TABLE J. 1

INSERTIONLOSSATPROPELLERHARMONICS

CABINMICROPHONENUMBER3 : STARBOARENGINE D COMPONENTS

Test '.Flight: RPM IBPF : InsertionLossatGivenHarmoniOrde c r_dB I

Conditio:nNumber: : Hz : I 2 3 4 5 6 7 B 9 10 r

i.............................................................................................................. i I

I I :Flight311520.0 76.0 0.5 4.B 6.3 15.5 II.I !4.6

: 2 ', - : 1570,0 7B.5 1,3 B.O 1.1 6,6 10.7 10.5

', 3 :Flight411572.5 78,6 15.6 -I.9 1.0 3.4 1.7 10.7 4,4 11,5

4 : 1517.5 75.9 1.2 3.7 4.4 -6,4 10.4 B.! 4.5 ',

', 0, : 1530.0 76.5 1.4 2.6 !.7 -3.4 6.9 -!.5 I

: 10 : 1572.5 7B,6 9.7 I0.I 1.4 2.9 -I.! 5.0 12.5

: I! ; 1515,0 75.G 2,1 -0.8 2,6 1.2 9.! 5.9 10.2 !:3.7 7,4 11.3 :

: !7 : 1517.5 75,9 -2.6 -3,B -3.6 -1.4 13.4 9.9 22.6 9.5 6.0 :

: 18 : 1572.5 7B.6 8.4 2.B 5.0 -1.5 ll.; 3.7 _, .2'_2 12.2 9.i !0.7

................................. I

CABINMICROPHDNENUMBER3 :PORTENGINECOMPONENTS

:--%;1 ....Ti[;iiI'T-'iii---'-iii'-,; ............... :::::::::::::::::::::::::::::::::::::::::: .................

ConditionINumber: : Hz : I 2 3 4 5 6 7 B 9 !0

.............................................................................................................. !

I :Flight311575.078.B -1,2 -6.B B.2 5.2 14.6 0.0 9.9

2 '. - I1525.0 76.3 -3.3 -4.6 11.2 4.3 7.5 1.5

3 :Flight4; 1527.576.4 -6.7 11,7 10.5 2.6 5.6 -7.0

4 = : 1572.578.6 -12.9-11.9 B.B 0.1 4,B 1.6 9,0 17.3

9 : : 1575.07B.B -17.6 6.3 10,4 4.9 5.1 -1.5 16.3 I0.',18.4

I0 : :1527.5 76.4 -3,3 B.5 4.2 3.9 6.7 12.1 10.1 ',6._=

Ii : : 1520.076.0 -2.9 2.5 3.4 -4.7 5.0 9.6 6.9 14.0 11.5 !5.0

17 : I 1570.0 78.5 0.5 2.0 -2.1 5,7 5.4 19.8 6.4 16,6 2%7 17,7

18 : : 1522.5 76.1 7.2 l.B 1.3 B,4 -1.7 8.2 8.5 15.5 20.5

........... I........i

-212-
TABLE J.2

INSERTIONLOSSATPROPELLERHARMONICS

CABINMICROPHONE NUMBER& : STARBOARDENSINECOMPONENTS

"-- iii....T-i[,[iiI-TiiiTiiF-T............... ilIIIi[IIilII;i-i ;Ii-i;I;IIiI-iTilI................. Tii

Conditioni Numbe=r I Hz I 1 2 3 4 5 t 7 B ! 10

Q ........................................ _ .....................................................................

1 _Flight311520.0 76.0 l.B -B.l 9.2 9.7 15.1 11.9

2 : I 1570.0 78.5 2.2 -0.2 5.7 -2.9 21.5

3 IFlight4',1572.5 78,6 1,0 -l.B -5.7 5,5 -0.2 9.4

4 I 1517.5 75.9 1.6 -2.9 -0.5 0.5 8.4 5,1 12.B

9 : 1530.0 76.5 2.3 -5,5 I.I -0.2 -5.0

I0 : 1572.5 7B.6 6.5 -B.B 0.0 2.6 -B.7 6,0 B.O 15.0

It I 1515.075.B 3.3 -1,2 -3.0 B.l 3.1 -3.8 IB.B 6.8 11.3 14.7

17 I 1517.575.9 -O.B -1.4 3.2 -10.9 -3.0 2.B 24.0 B.9 6B.2

ZB I 1572.57B,6 2.B -4.3 &.O 2.3 3.2 -2.8 !0,2 6.9 9.0, !O._

CABINMICROPHONE NUMBER6 : POETENGINECOMPONENTS

................................................................................................................

Test IFlight: RPM ; BPF I InsertionLossatGivenHarmonicOrder,dB

ConditicInNumberI I Hz ; I 2 3 4 5 6 7 B 9 I0

1 IFZight31 1575.078.8 10.9 -B.5 -9.9 -6.5 l&.B -2.5 13.7

2 I - ; 1525.076.3 &.2 -11.3-13.6 -2.6 B.O -0.7

3 IFlight411527.576.4 4.7 -13.3-14.5 -9,3 -3.1 -1.0 9.2 13.2

4 I I 1572,5 78,6 10.7 -%0 -9.2 -1.3 2.6 -1.3 6.0 5.9

O. ; 11575.0 78.8 11.7 -6.B -4.6 -!.2 2.3 -5,6 /,.7 B.O 5.0

I0 I I 1527.5 76.4 3.9 -10.4 -!O.B 1.6 0.9 -7.7 3.3

11 I I 1520.0 71LO -O.& -lB.2 -7.0 1,3 _,a -2.3 2.B !4.6 15.B _.0.4

17 ; I 1570.07B.5 12.0-10.2 -5,6 -3.4 -1.3 B.2 ll.B %9 9.6

IB I ; 1522.576.1 6,2 -9.3 -5.8 -0.I -2.6 9.5 7.1 15.6

-2"13-
TABLE J. 3

ONE-THIRDOCTAVBAENDSOUNPRESSU D LREEVELS. FLI6HT13- FLI6HT#4

CABINMICROPHONENUMBE3R

Band Insertion Loss,dB "

Center ...................................................................................

Frequency TestCondition B

Hz I 2 3 4 5 6 7 B 9

25 -13.5 -12.7 -14.5 -17.3 -13.7

32 -1.7 1.0 -6.5 -B.7 -7.5

40 -3.7 -4.3 -5.5 -4.2 -3.3

50 -4.3 -5.3 -8.5 -7.C' -7.7

63 -0.2 -2.0 -4.0 -2.8 -1.2

80 -1.3 -2.7 -4.5 -5.0 -5.2

100 -0.5 -I.0 -1.5 -2.3 -2.0

125 2.7 2.2 3.8 2.3 3.5

160 -0.5 2.0 5.5 -1.0 4.3

200 6.8 7.0 6.5 5.3 5.5

250 7.3 5.0 5.7 7.7 6.5

315 12.3 10.3 4.7 4.3 4.5

400 12.0 11.2 6.8 9.5 8.0

5(,0 13.0 11•.5 13.9. I_._..., %3

630 17.3 16.2 15.8 14.5 14.8

800 16.3 15.8 15.3 16.5 16.2

I000 13.7 14.0 15.5 17.0 17.2

1250 14.0 13.8 15.5 16.8 17.0

1600 14.2 13.7 16.3 17.5 17.7

2000 13.8 13.5 13.3 14.7 15.0

2500 14.0 12.8 14.8 15.5 16.0

3150 12.8 12.0 12.5 13.8 14.0

4000 9.7 9.5 10.2 11.5 11.3

5000 7.0 7.2 8.5 9.0 9.5

-214-
TABLE J.3 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT13 - FLIGHTI4

CABINMICRDPHDNENUMBER3

Band InsertionLoss,dB

Center ............................................................................

Frequency TestCondition

Hz I0 II 12 13 14 15 16 17 IB

25 -14.7 -13.2 -15.0 -10.3 -13,7 -14.2

32 -6.2 1.0 -3.7 -5.5 -I0.7 -B.5

40 -3.5 -2.7 -3.2 -1.5 -3.5 -2.0

50 -8.0 -1.5 -3.0 -3.5 -2.8 -3.8

63 -I.0 2.2 -2.3 0.0 -I.3 7.0

80 0.5 2.5 -2.2 0.2 -0.B 7.5

I00 -0.2 1.8 -2.5 0.5 -0.3 2.3

125 4.0 1.5 2.0 1.0 0.8 2.5

150 8.5 -0.2 3.3 0.0 0.5 2.8

2)0 4.8 l.B 3.5 2.8 3.0 4.5

250 2.7 2.2 3.5 -0.5 -2.5 3.2

315 4.5 3.0 1.5 4.2 4.8 5.3

400 8.5 8.7 8.5 9.0 11.2 8.2

500 12.7 Ii.0 12.0 11.2 13.2 7.7

830 17.0 15.5 17.0 I,_'.:" 15.0 15.0

800 16.0 15.0 15.0 I__',: _ 14.0 13.5

1000 17.0 13.7 13,5 15.2 15.0 14.3

1250 16.2 12.5 12.0 15.8 18.2 16.3

16))0 !6.5 13.8 14.3 17.3 16.3 16.2

2000 14.5 10.5 13.0 13.2 12.3 13.3

2500 15.5 12.8 13.5 13.B 12.8 13.3

3150 13.0 9.5 10.2 11.5 II.0 II.0

4000 I0.5 6.5 7.7 B.2 B.O 8.3

5000 9.0 4.3 6.7 7.0 6.0 7.0

-215-
TABLE J. 4

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT#3 - FLIBHTI4

CABINMICROPHONENUMBER6

Band InsertionLoss,dB

Center ............................................................................-

Frequency TestCondition

Hz I 2 3 4 5 6 7 B 9

........... i •

25 -I.8 -1.3 -1.8 -3.8 -0.5

32 12.5 15.2 6.5 4.2 5.5

40 2.7 3.2 3.0 4.3 5.3

50 -%0 -8.3 -%3 -8.3 -8.0

63 6.2 5.5 4.5 7.3 7.5

80 8,2 5.0 3.8 9.0 9.2

100 7.0 3.5 2.7 7.2 7.5

125 -2,3 -4.3 -5.3 -3.5 -3.5

160 -6.8 -6.8 -6.3 -7.0 -5.3

200 -1.3 -1.8 -2.0 -4.0 -2.0

_uO -6.3 -4.8 -7.8 -5.8 -3.5

315 3.0 4.3 4.3 2.5 2.3

400 14.0 13.8 7.5 6.5 5.3

500 13.5 13.0 12.0 9.8 6.7

630 19.0 19.0 17.2 18,0 17.3

800 1e.8 17.8 17.5 17.5 17.8

I000 15.5 16.3 17.0 17.7 18.3

1250 14.0 14.7 17.7 18.B 20,0

1600 14.2 14.5 17.5 18.5 20.0

2000 13,7 12.3 16.5 17.2 18.3

2500 14.2 14.3 14.7 16.5 17.0

3150 14.7 14.7 14.5 15.3 15.0

4000 12.5 12.2 12.5 12,5 13.0

5000 10.3 10.3 10.3 11.2 11.5

-216-
TABLE J.4 (CONTINUED)

ONE-THIRDOCTAVEBANDSOUNDPRESSURELEVELS.FLIGHT13- FLIGHTI4

CABINMICROPHONENUMBER6

Band InsertionLoss,dB

Center ............................................................................

Frequency TestCondition

Hz I0 II 12 13 14 15 16 17 IB

25 -I.0 -I.0 -2.0 2.7 -0.5 -0.5

32 7.5 15.0 B.B 7.7 2.5 4.2

40 4.2 5.5 5.3 6.0 4.B 6.0

50 -7.B -3.3 -B.B -5.B -7.B -5.3

63 5.5 4.3 -0.5 .0 4.0 4.5

BO 5.B 3.7 -0.5 0.2 7.0 4.3

100 4.3 2.7 I.B 1.B 5.B 3.8

125 -6.3 -1.0 -%8 -7.5 -3.B -5.3

160 -9.5 -I.0 -15.5 -12.3 -6.5 -7.0

200 -0.5 0,3 -3,5 1,3 .0 1.2

250 -3.B .0 -4,3 -3.0 -2,B 1,3

315 4.5 9.5 3.7 3.5 -1.3 3.0

400 5.B 10.7 7.0 5.B 2.7 5.5

500 10.2 11.7 7.2 9.2 10.0 6.B

630 17.0 16.5 16.7 IB.O 16.B IB.O

BOO 17.3 17.0 17.0 17.3 17.0 1B.3

1000 17.3 17.0 15.5 17.B 17.3 17.2

1250 18.8 16.B 18.0 20.2 1%7 19.B

1600 1B.5 17.0 16.5 21.0 20.0 21.0

2000 16.7 15.0 15.5 17.B 16.3 17.5

2500 16.0 15.3 14.7 16.7 16.0 16,0

3150 15.0 14.0 14.5 15.3 13.7 15,3

4000 12.7 10.B 11.7 13.0 12.5 12,8

5000 10.3 9.3 10.5 11.5 11.2 II.B

-217-
-218-
APPENDIX K

InsertionLoss Providedby Treatment (Differencesin Harmonic and

• One-ThirdOctave Band Sound PressureLevels for Flights 3 and 4;

Adjusted for Changes in Exterior Sound PressureLevel).

-219-
TABLE K. 1

INSERTIONLOSSATPROPELLEHARMON R ICS,ADJUSTEFOR D CHANGESINEXTERIORSOUNDPRESSURELEVEL

CABINMICROPHONNUMBER E 3 : STARBOARDENGINECOMPONENTS

Test IFlight_ RPM IBPF _ InsertionLossdB

ConditionI NumberI I Hz I I 2 3 4 5 & 7 B 9 tO

1 IFlight 1520.076.0 1.1 5.5 6.& 17.0 13.1 16.1

2 _ 3 1570.078.5 1.B B.6 O.B 7.5 11.4 11=B

3 I - 1572.5 7B.6 16.5 -1.1 2.8 4.7 3.B 11.1 &.3 12.4

4 _ Flight 1517.575.9 1.7 4.0 5.0 -5.4 10.7 B.5 4.6

9 I 4 1530.0 76.5 0.9 2.9 1.7 -3.2 6.6 0.0

10 _ 1572.57B.6 10.0 9.B 2.2 3.1 -0.4 6.5 12.5

11 I !515.0 75.B 2.2 -0.5 2.B 1.5 B.7 6.0 I0.6 11.6 B.2 9.9

17 I 1517.575.9 -2.6 -3.1 -3.3 -1.5 12.5 9.5 22.1 B.3 5.B

IB I 1572.5 7B.6 B.5 2.2 5.3 -2.1 10.4 3.9 ?=I.=_ 12.3 B.7 10.3

I ........................ . ................................................

TABLE K.2

CABINMICROPHONE& : PORTENSINECOMPONENTS

I Test IFlightI RPM IBPF I InsertionLoss,dB

IConditionI NumberI I Hz ', I 2 3 4 5 6 7 B 9 10

I 1 IFligh41t 1575.0I 7B.B 15.2 -4.4 -5.B -1.9 21.5 1.6 18.2

2 = - I 1525.0I7L3 IO.B -6,6 -B.7 1.9 12.1 4,9

3 _FIight311527.5_ 76,4 B.6 -B.4 -9.7 -5.0 I.I 4.3 14.9 17.B

4 = _ 1572.5',7B.6 14.3 -5.B -5.3 2.3 6.1 2.5 %2 9.7

I 9 = = 1575.0I7B.B 15.1 -3.6 -1.3 2.B 6.5 -2,9 !0.5 12.1 e.&

= 10 ; _ 1527.5=76.4 7.5 -6.0 -6.! 5.B 5.4 -1.3 B.I

12 I ; 1520.0;76.0 2.4 -15.0 -3.9 4.7 7.1 I.I 6.4 17.3 20.5 13.7

I 17 I I !570.0I7B.5 14.8 -6.5 -1.9 0.I 2.3 11.5 15.3 13.7 13.1

I IB I I 1517.5_75.9 9.2 -5.B -2.B 3.1 1.5 13.7 10.B 19.3

I........... I........_........_..................................................................

-220-

Standard Bibliographic Page

1. Report No. 12. Government Accession No. 3. Recipient's Catalog No.

NASA CR-178004

4. Title and Subtitle 5. Report Date

IN-FLIGHT ACOUSTIC MEASUREi-lENTS ON A LIGHT November 1985

TWIN-ENGINED TURBOPROP AIRPLANE 6. Performing Organization Code !

I

7. Author(s) 8. Performing Organization Report No.

J. F. Wilby, C. D. McDaniel and E. G. ~.vilby 5838

9. Performing Organization Name and Address 10. Work l:nit No.

BBN Laboratories Incorporated

21120 Vanmven Street 11. Contract or Grant No.

Canoga Park, CA 91303 N2'.C::l-lht;?l

12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered

National Aeronautics and Space Administration Contractor Report

~'~ashington, DC 20546 14. Sponsoring Agency Code

15. Supplementary Notes

NASA Langley Technical Monitor: Dr. John S. Hixson

Final Report

16. Abstract

Four series of flight tests were conducted to measure sound !.Jressure

levels inside and outside the cabin of a twin-engined turboprop

airplane. Particular emphasis was placed on harmonics of the propeller blade passage frequency. The cabin 'vas unfurnished :l:or the

first three flights, \'lhen the main objective \-JaS to investigate the

repeatability of the data. For the fourth flight, the cabin \-las

treated with fiberglass batts. Typically, the exterior sound pressure levels \-lere found to vary 3 to 5 dB for a given harmonic, but

variations as high as 8 dB were observed. The variability of

harmonic levels \.;i thin the cabin was slightly higher but depended

on control of the relative phase between the propellers; '-lhen phase

was not controlled the averaae variability was about 10 dB. ~;oise

reductions provided by the fuselage structure were in the range of

20 to 40 dB, when an exterior microphone in the plane of rotation

of the propeller \'las used as reference. Installation of 5 ern of'

fiberglass blanket on the cabin walls and ceiling increased the

noise reduction at frequencies above about 200 HZ, but there Has

an apparent decrease in noise reduction at some 10vler frequencies.

17. Key Words (Suggested by Authors(s) 18. Distribution Statement

Airplane Interior Noise

Propeller Noise

Flight Test Unclassified - Unlimited

Data Repeatability

Noise Reduction Subject Category 71

119. Security Cla.ss,ift~f this report) 120. SecuritI Cla.ssif.~f.this page) 21. :"0. of Pages 122. Price

Unclassl led Unc aSSl led 230 All

For sale by the National Technical Information Service, Springfield, Virginia 22161

l"ASA Lanr10y Form 63 (Juno 1985)

a