NASA Technical Memorandum 104326

Flight and Static Exhaust Flow

Properties of an F110-GE-129

Engine in an F-16XL Airplane

During Acoustic "rests

Jon K. Holzman, Lannie D. Webb, and Frank W. Burcham, Jr.

NASA Dryden Flight Research Center

Edwards, Cafifornia

1996

National Aeronautics and

Space Administration

Dryden Flight Research Center

Edwards, California 93523-0273

CONTENTS

F-16XL AIRCRAFT DESCRIPTION ................................................... 3

Inlet Description ................................................................. 3

Engine Description ............................................................... 6

MEASUREMENTS

................................. . ............................... 6

Aircraft

........................................................................

Engine ........................................................................ 7

Acoustics Measurements

..........................................................

Flyover Tests

................................................................

Flyover Space Positioning ...................................................... 8

Static Acoustic Tests

......................... ° ................................ 8

Meteorology .................................................................... 9

TEST PROCEDURES

................................. . ............................. 9

Climb-To-Cruise Tests

........................................................... 0

ANOPP Tests

.................................................................. 0

Static Tests

.................................................................... 11

ANALYTICAL TECHNIQUES ...................................................... 11

Engine Exhaust Flow Properties ................................................... 11

F110-GE-129 Digital Engine Model ' ............................................... 12

Engine Model Description ..................................................... 12

Data Selection Procedure

...................................................... 2

Engine Model Inputs ......................................................... 12

Engine Model Output ......................................................... 14

Exhaust Flow Properties ...................................................... 14

Ideal or Jet Expansion Parameters

........................... • ................... 14

Area Ratio Parameters

........................................................ 4

Exhaust Static Temperature .................................................... 14

Local Speed of Sound and Exhaust Velocities ..................................... 15

RESULTS AND DISCUSSION

" ° ' " " " ° " " * ............................. * .... ° ......... _5

Verification of F 110-GE- 129 Engine Deck

........................................... 19

Ground Static Test Results

........................ • ............................... 23

°,.

nl
Flyover Exhaust Flow Properties Results ............................................ 23

CTC Test Results ............................................................... 23

ANOPP Test Results ............................................................ 24

CONCLUDING REMARKS ......................................................... 25

26 REFERENCES ...................................................................

TABLES

1. Climb-to-cruise test points ....................................................... 10

2. ANOPPtest points ............................................................. 10

3. Acoustics flight tests for the F-16XL, ship 2 ......................................... 11

4. F-16XL, ship 2, ground run test ................................................... 15

5. CTC test data ................................................................. 17

6. ANOPP flyover test data ......................................................... 18

FIGURES

1. The F-16XL, ship 2, airplane ...................................................... 4

2. The F-16XL, ship 2, inlet (893 in 2 capture area) ....................................... 5

3. Cutaway view of the F110-GE-129 engine and station designations ....................... 6

4. Ground track and array layout on Rogers Dry Lake, Edwards, CA ................. , ...... 7

5. Microphone array for the F-16XL, ship 2, ground static acoustic survey .................... 8

6. Photograph of the F-16XL, ship 2, ground acoustic test showing 3 microphones

in foreground .................................................................. 9

7. Ambient temperature and standard day temperature for the acoustics flyover tests ........... 13

8. Comparison of measured and deck-calculated parameters, ground run .................... 20

9. Comparison of measured and deck-calculated parameters, climb-to-cruise tests ............. 21

10. Comparison of measured and deck-calculated parameters, ANOPP tests ................... 22

11. Exhaust flow properties, F110-GE-129 engine in F-16XL, ship 2, ground run .............. 23

12. Exhaust flow properties, F110-GE-129 engine in F-16XL, ship 2, climb-to-cruise

tests, all tests at intermediate power, for altitudes, see table 5 ............................ 24

13. Exhaust flow properties, F110-GE-129 engine in F-16XL, ship 2, ANOPP tests,

3800 ft altitude ................................................................ 25

iv
ABSTRACT

The exhaust flow properties (mass flow, pressure, temperature, velocity, and Mach number) of the

F 110-GE-129 engine in an F-16XL airplane were determined from a series of flight tests flown at NASA

Dryden Flight Research Center, Edwards, California. These tests were performed in conjunction with

NASA Langley Research Center, Hampton, Virginia (LaRC) as part of a study to investigate the acoustic

characteristics of jet engines operating at high nozzle pressure conditions. The range of interest for both

objectives was from Mach 0.3 to Mach 0.9. NASA Dryden flew the airplane and acquired and analyzed

the engine data to determine the exhaust characteristics. NASA Langley collected the flyover acoustic

measurements and correlated these results with their current predictive codes. This paper describes the

airplane, tests, and methods used to determine the exhaust flow properties and presents the exhaust flow

properties. No acoustics results are presented.

NOMENCLATURE

A8

A9

AE8

AE9

AFFI'C

AGL

ANOPP

CTC

EGT

Vg

GAM7

jet

M9

M jet

Mach

Meas

NPR

N1

N2

OH

P1

Ps3

PT2.5

exhaust nozzle physical area at the throat, in 2

exhaust nozzle physical area at the exit plane, in 2

exhaust nozzle effective throat area, in 2

exhaust nozzle effective exit-plane area, in 2

Air Force Flight Test Center, Edwards AFB, California

above ground level

Aircraft Noise Prediction Program

climb to cruise

exhaust gas temperature downstream of the turbine, °R

gross thrust, lbf

specific heat ratio of exhaust gas at nozzle entrance

location where exhaust flow has expanded to ambient pressure

nozzle exit Mach number based on nozzle expansion ratio

fully expanded jet Mach number

Mach number

measured

nozzle pressure ratio (P8/Pamb)

fan rotor speed, rpm

core rotor speed, rpm

overhead

engine face total pressure, lbf/in 2

compressor discharge static pressure, lbf/in 2

fan discharge total pressure, lbf/in 2
P7

P8

Pamb

PLA

PLF

Ps9

Tamb

T1

T8

Ts9

Tsjet

V9

Vjet

WFE

W8

exhaust nozzle entrance total pressure, lbf/in 2

exhaust nozzle throat total pressure, lbf/in 2 '

ambient static pressure, lbffin 2

power lever angle, deg

power for level flight

exit plane static pressure, lbffin 2

ambient temperature, deg

engine face total temperature, °R

exhaust-nozzle rnixedjet total temperature at the throat, °R

exhaust nozzle exit static temperature, °R

fully expanded jet static temperature, °R

velocity at nozzle exit, from M9, ft/sec

fully expanded nozzle jet velocity, ft/sec

core engine fuel flow, lb/h

mass flow rate at the exhaust nozzle throat, lb/sec

INTRODUCTION

Exhaust flow properties (mass flow, temperature, pressure, velocity, and Mach number) of an engine

are key in determining the acoustic characteristics. Airport noise is one of the key issues in determining

the environmental acceptability of proposed supersonic transport airplanes. These airplanes will probably

be powered by engines operating at high nozzle pressure ratios (NPR) and high exhaust jet velocities.

Concern exists not only for noise produced during takeoff and landing but also for noise produced along

the flightpath of the airplane during the subsonic portion of the climb out for a distance of up to 50 miles.

To determine the engine noise for these transport designs, acoustic codes, such as the Aircraft

Noise Prediction Program (ANOPP), are used. 1 These codes were developed and validated using data

acquired from engines with NPR's and flight speeds lower than that planned for supersonic transports.

Doppler amplification of the shock noise in the forward approach arc of the vehicle flightpath was of

particular concern.

For these reasons, NASA Langley Research Center, Hampton, Virginia (LaRC), and Dryden Flight

Research Center, Edwards, California, jointly conducted tests to acquire in-flight acoustic data for high

NPR engines. Results of these tests would be used to update and validate the current noise predictive

codes. The two main flight test objectives were to assess subsonic climb-to-cruise (CTC) noise using an

aircraft with high NPR engines and to obtain an improved noise database to validate the ANOPP and other

noise predictive codes. The test airplanes included an F-18 powered by two F404-GE-400 engines,

(General Electric Company, Lynn, Massachusetts) and an F-16XL, ship 2, powered by a single F110-GEl 29 engine (General Electric Company, Evendale, Ohio). The F-18 exhaust characteristics were presented

in reference 2. NASA Dryden responsibilities for the F- 18 airplane are discussed in reference 3. For the

F- 16XL, ship 2 tests, the responsibilities were to plan and conduct the flyover tests, record and analyze the

2
flight data, determine the airplane space position, determine the engine exhaust gas flow properties, and

conduct a ground static acoustic survey. NASA Langley responsibilities were to setup the microphone

array, record the noise measurements, merge the acoustic and space position data, analyze and evaluate

the acoustic data, and correlate these data with Dryden-determined engine exhaust properties. The preliminary acoustic results are presented in the footnoted report.

The F-16XL, ship 2, study consisted of flights over a microphone array at varying speeds and

altitudes. Two types of flight tests were conducted: subsonic CTC noise determination and ANOPP predictive code validation. In the subsonic CTC portion of the study, flyovers were conducted at altitudes

from 3,800 to 12,300 ft and from Mach 0.3 to Mach 0.95 all at an intermediate (maximum nonafterburning) power setting. For the ANOPP evaluation flyovers, the tests were flown at 3,800 ft and from

Mach 0.3 to Mach 0.95. A static ground-level engine-run test was also conducted over the power setting

range from idle to intermediate power in order to establish baseline exhaust acoustic noise levels with no

forward airplane velocity.

This paper describes the F-16XL airplane and Fl10-GE-129 engine, presents the flight tests performed using the F-16XL airplane, documents the test and analysis techniques used to calculate the

engine flow properties, and presents the engine exhaust flow properties. Acoustics data are not presented.

Use of trade names or names of manufacturers in this document does not constitute an official endorsement of such products or manufacturers, either expressed or implied, by the National Aeronautics and

Space Administration.

F-16XL AIRCRAFT DESCRIPTION

The F-16XL airplane has a "cranked" delta wing and is an extensive modification of the F-16 airplane

(fig. 1). Two aircraft were built by Lockheed-Martin (formerly General Dynamics, Fort Worth, Texas).

The F-16XL, ship 2, a two-seat aircraft, has a length of 54.2 ft, a wingspan of 34.3 ft, and a maximum

weight of approximately 36,000 lb. Figure l(a) shows an in-flight photograph and figure l(b) shows a

three-view drawing with key dimensions of this airplane. It has a maximum Mach number of

approximately 2.05 and a nominal design load factor of 9 g which provides a large performance envelope

for flight research. The F-16XL, ship 2, aircraft is powered by a single F 110-GE-129 afterburning turbofan engine mounted in the rear fuselage.

Inlet Description

The F-16XL, ship 2, air inlet consists of a normal shock inlet mounted below the front fuselage

followed by an S duct to the engine. Inlet size and pressure recovery characteristics are important in

determining the engine exhaust flow conditions. A front view of the inlet is shown in figure 2(a). The

inlet has a geometric capture area of 893 in 2. This area is 56 in 2 larger than the F-16 A/B small inlet but

slightly smaller than the F- 16 C/D big inlet. Figure 2(b) shows the total pressure recovery of this inlet, as

determined from wind-tunnel tests, for a range of engine-corrected airflows and Mach numbers.

*Jeffrey J. Kelly, Mark R. Wilson, John Rawls Jr., Thomas D. Norum, and Robert A. Golub, F-16XL and F-18 High

Speed Acoustic Flight Test Data Base, NASA CD TM-10006, 1996. (This is a controlled distribution document. Direct

inquiries to the author of this document at NASA Langley Research Center Aeroacoustics Division.)
(a) In-flight photograph.

EC-91-646-1

[-- 54.2 _ _,

_.-.-_, _ IUULII.JJU_ '

(b) Three-view drawing.

Figure 1. The F-16XL, ship 2, airplane.

17.6 ft

960599

4
I

55.44 in. _'2

17.47 in.

Throat _ I

contour ___ contour

9606O0

(a) Drawing of the inlet capture area and throat area.

q.

1.0

.95

.90

Ram

pressure .85

recovery

,8O

.75

.70 I I I I I I

50 1O0 150 200 250 300

Corrected airflow, Iblsec

_D601

(b) Inlet ram pressure recovery.

-o--

-El--

-N-

-QMach

number

2.0

1.8

1.6

1.4

1.2

1.0 - 0.5

0.4

0.3

0.2

0

Figure 2. The F-16XL, ship 2, inlet (893 in 2 capture area).
Engine Description

For the acoustic tests, the F-16XL, ship 2, was powered by the F 110-GE-129 increased performance

engine. This two-spool, low-bypass, axial-flow turbofan engine with afterburner has a maximum thrust of

29,000 lbf. Figure 3 shows a cut away schematic view of the engine depicting the station designations,

including the "jet" station where the engine exhaust flow has adjusted to free stream static pressure. The

engine features a three-stage fan driven by a two-stage, low-pressure turbine and a seven-stage, highpressure compressor driven by a single-stage, high-pressure turbine. Variable inlet guide vane geometry

is incorporated into the fan and the first four stages of the high-pressure compressor. A fan/core mixer is

just upstream of the afterburner. The exhaust nozzle is of the convergent-divergent type with a variable

throat area. The engine is equipped with a digital engine control unit which controls the fuel flows, rotor

speeds, variable geometry, pressures, and temperatures in the engine. Idle power is at 20 ° power lever

angle (PLA) setting, and intermediate (maximum nonafterburning) power is at 85 ° PLA. At this latter setting, the engine produces NPR similar to those proposed for some versions of future supersonic transport

engine designs.

_- Compressor

- Fen \ ,- Combustor

_r \ _ _-- High-pressure turbine F Afterburner

\ _ \ /--Low'pressure turbine /___ N°zzle

I ' /L ---- 'Jl I

Station __ jet

number 2.1 2.5 3 4 5 6 7 8 9 (l_jet= Pamb)

Digital engine

control unit 9so602

Figure 3. Cutaway view of the F110-GE-129 engine and station designations.

MEASUREMENTS

The F-16XL, ship 2, airplane was instrumented to measure parameters of interest for the acoustic flyover test. Aircraft and engine parameters were included. In addition, acoustic, meteorological, and

airplane space-positioning measurements were made on the ground.

Aircraft

The F-16XL, ship 2, Mach number and altitude were obtained from the pitot-static probe on the noseboom. Pressures from the pitot probe were fed to the central airdata computer where Mach number and

altitude were calculated. The aircraft also had an inertial navigation system for accurate velocity and

position determination which was helpful in flying the airplane as close as possible to the designated

6
ground-track profile over the Edwards, California, fly-by line. Angle of attack and angle of sideslip were

measured by vanes on the noseboom. These data were recorded at 10 samples/sec onboard on a lO-bit

pulse code modulation (PCM) data system and were also transmitted to the ground. The airplane was

equipped with a C-band radar beacon to aid in precise space positioning.

Engine

The F110-GE-129 engine was extensively instrumented. For this paper, the parameters of interest are

those used as inputs to and for comparison with the F 110-GE-129 engine deck and for the acoustic analysis. These parameters include PLA; engine face total temperature, T1; fan discharge total pressure, PT2.5;

compressor discharge static pressure, Ps3; core engine fuel flow, WFE; fan rotor speed, N1; core rotor

speed, N2; engine exhaust gas temperature (EGT); and exhaust nozzle physical area at the throat, AS.

Acoustics Measurements

Flyover Tests

For the CTC and ANOPP tests, the acoustic data were measured with an analog and digital microphone array positioned along the flyby line on Rogers Dry Lakebed (fig. 4). This location provided a

good proximity to the tracking radar, an adequate distance from the Edwards, California, main runway,

and a large flat area suitable for acoustics measurements. The analog microphone setup was similar to the

setup used by NASA Dryden during the static ground-run engine acoustic test.

Typical ground

NASA

/

North

Array location

Radar site

Fly-by-line

960603

Figure 4. Ground track and array layout on Rogers Dry Lake, Edwards, CA.
Flyover Space Positioning

The NASA Dryden FPS-16 radar was used to track the radar beacon on F-16XL, ship 2, airplane during the acoustic flyovers. These data were used in the control room to assist the pilot in lineup, establish

the time for beginning and completing data runs, and determine the validity of the track for each flyover.

These data were also used by NASA Langley in the postflight analysis to determine the position of the

airplane for correlation with the microphone data.

Static Acoustic Tests

For the static tests conducted by NASA Dryden, a 24-microphone array was located on a large flat

taxiway area (fig. 5). Nominal microphone placement was every 7.5 ° on an arc 99 ft from the engine

exhaust centerline. Inverted microphones were mounted inside windscreens with the diaphragms 0.5 in.

above a thin aluminum plate which was taped to the concrete or asphalt surface. This setup allowed for

measuring acoustic exhaust noise free of ground reflections.

Asphalt O

o

Concrete

Concrete

Asphalt

0 0

0

0

0 ) 0 0

0

0

Nominal spacing

every 7.5 °

O

O

O

O

O

O

96O604

Figure 5. Microphone array for the F-16XL, ship 2, ground static acoustic survey.

Figure 6 shows the airplane positioned for the static test. Three of the microphones are visible. The

NASA Dryden acoustics van was used to record the 24 channels of microphone data. Two 14-track tape

recorders were installed in the mobile trailer. Twelve channels of acoustic data were recorded on each of

the two recorders; meanwhile, the remaining two channels were used to record the time and the pilot's

event marker. Each of the 24 microphone stations was battery powered and consisted of a condenser

microphone, a preamplifier, and a line driver amplifier. Each station was connected to a separate line

driver by 1000 ft of shielded, coaxial signal cable. The line driver signal was in turn connected to one of

the recorder data channels in the trailer, using a 1000-ft length of neoprene-covered cable containing a

shielded, twisted pair of copper signal wires. The trailer also contained a weather station for recording
local temperatures as well as wind velocity and direction in the area of the microphone array and radios

for communication with the airplane.

Figure 6. Photograph of the F-16XL, ship 2, ground acoustic test showing 3 microphones in foreground.

Meteorology

Atmospheric properties affect the propagation of acoustics and are one of the inputs into the ANOPP.

Conditions for the flight data were determined from four sources:

1. The F-16XL, ship 2, onboard measurements

2. The weather balloons

3. A ground weather station at the acoustics van

4. A tethered balloon located near the flyover array

The onboard measurements were primarily winds aloft data readout from the airplane inertial system and

T1. The tethered balloon was raised and lowered periodically during the tests using a 1500-ft tether.

TEST PROCEDURES

To satisfy dual objectives of the program, two flight tests were conducted: subsonic CTC noise determination and ANOPP predictive code validation. In both cases, obtaining acoustic data during the period

when the airplane was more than 10° to 15 ° above the horizon as measured from the center of the acoustic array was desired. Distances of the start and end points away from the acoustic array were, therefore, a

function of the test altitude. At the lowest test altitude, 1500 ft above ground level (AGL), this distance

was approximately 1 mile. The pilot flew along the fly-by line using a combination of visual navigation,

onboard inertial navigation, and callouts from the control room.

9
Climb-To-Cruise Tests

The flight matrix for the CTC runs consisted of level flight accelerations over the acoustic array at

various Mach numbers and altitudes. During these runs, the engine power setting was constant at 85 °

(intermediate) in order to obtain the maximum engine NPR. Table 1 lists the CTC desired test conditions.

Test altitudes desired varied from an altitude of 3,800-32,300 ft, and the Mach numbers ranged from 0.30

to 0.90.

Table 1. Climb-to-cruise test points.

Mach Altitude,

number fl

0.3 3,800

0.6 7,300

0.65 12,300

0.75 22,300

0.9 32,300

For the CTC condition, the pilot first stabilized the aircraft at the desired altitude and just below the

desired Mach number. As the airplane approached the acoustic start point, based on a radio call from the

control room, the throttle was advanced to the intermediate power setting. Then the engine was allowed

to stabilize for approximately 5 sec before the start of the test run. The aircraft would accelerate depending on the degree of excess thrust through the desired test conditions in level flight. Some acoustic runs

were initiated directly over the center of the array with the run terminating when the elevation angle was

again 15 ° above the horizon. At some flight test conditions, the aircraft speed brakes were deployed to

reduce the acceleration during the acoustic data acquisition. Because of aircraft acceleration no data were

obtained at the 22,300 and 32,300 ft altitudes for the F-16XL, ship 2, tests.

ANOPP Tests

The ANOPP code evaluation tests were flown at constant Mach number and at an altitude of 3800 ft

(1500 ft above the local ground level). Test Mach numbers ranged from 0.30 to 0.95 (table 2). For the

ANOPP tests, the throttle setting was the power level flight (PLF) at constant speed and varied from

about 35 ° to 57 ° . For these runs, the pilot was vectored over the microphone array in similar fashion to

the CTC tests. Once power was set, it was not changed during the flyover, so small changes in Mach

number occurred. Speed brakes were not used for ANOPP tests.

Table 2. ANOPP test points.

Mach Altitude, Power setting,

number ft deg

0.3 3800 - 48 °

0.6 3800 - 35 °

0.8 3800 - 47 °

0.95 3800 - 56 °

Table 3 shows the CTC and ANOPP tests that were flown during three flights. Note that all of the

CTC tests resulted in a significant change in Mach number during the run, which was caused by the

10
excessthrust.Repeatestswereflown at someconditions.Thedatashownwith tablerunletterswerethe

primary acousticstestsfor CTCandANOPPtests.Exhaustflow propertiesfrom thesetestsareshownin

table4.

Table3.Acousticsflight testsfortheF-16XL, ship2.

Testfor tablein Machnumber Altitude, Runlegs, Run

thisreport start-end ft mi type

Flight 1

A 0.33-0.75 -3,800 +_2 CTC

B 0.58-0.95 -7,300 +_4 CTC

C 0.70-0.92 - 12,300 +7 CTC

D 0.31-0.79 -3,800 +2 CTC

Flight 2

0.31-0.61 -3,800 +-2 CTC

0.34-0.55 -3,800 +-2 CTC

0.31-0.48 -3,800 0 to -2 CTC

0.32-0.47 -3,800 0 to -2 CTC

0.60-0.73 -7,300 +4 CTC

Flight 3

E

F

G

H

0.33-0.33

0.31-0.28

0.61-0.58

0.60-0.60

0.80-0.81

0.80-0.80

0.95-0.95

0.94-0.95

0.30-0.58

0.28-0.59

0.28-0.49

0.31-0.50

-3 800

-3 800

-3 800

-3 800

-3 800

-3 800

-3 800

-3 800

-3800

-3 800

-3 800

-3 800

+_2 ANOPP

+2 ANOPP

+2 ANOPP

+2 ANOPP

+-2 ANOPP

+2 ANOPP

+2 ANOPP

+2 ANOPP

+2 CTC

+-2 CTC

+_2 CTC

0 to 2 CTC

Static Tests

For the static tests, the F- 16XL, ship 2, aircraft was tied down, and engine power setting was varied to

achieve engine pressure ratio increments of 0.1 from idle to intermediate power (98.5 percent N2) and

then back to idle. At each test point, the engine was allowed to stabilize for 1 min; then acoustic data were

acquired for 30 sec. These tests were conducted with the wind speed below 5 kn to minimize wind noise.

Atmospheric data were obtained from the NASA Dryden acoustics van and from the Air Force Flight

Test Center (AFFTC), Edwards, California, observations.

ANALYTICAL TECHNIQUES

Engine Exhaust Flow Properties

Jet-mixing and shock cell noise are two primary sources of noise for high-NPR engines during takeoff and subsonic climb (ref. 2). These noise sources are primarily affected by the aircraft velocity,

11
exhaust-exitMachnumberandvelocity,andNPR.For acousticanalysis,exhaustcharacteristicsareoften

definedatthenozzleexit (station9) andalsoat anassumedfully expandedcondition(stationjet) (fig. 3).

Jet-mixing noise is primarily a function of the difference between the fully expanded nozzle jet velocity,

Vjet, and the free stream velocity. Shock cell noise is a function of the difference between the fully

expanded jet Mach number, Mjet, and the nozzle exit Mach number based on nozzle expansion ratio, M9.

At the point where M9 = Mjet, the shock cell noise is diminished. Nozzle exit velocity from nozzle exit,

V9, and Mach number M9 are based on the aerothermodynamic characteristics of the flow at the nozzle

exit plane (fig. 3).

Fl10-GE-129 Digital Engine Model

Flight and ground test data from the instrumented engine did not directly measure values of pressure,

temperature, velocity, and mass flow at station 9. At station jet, these data did not provide the data needed

for the evaluation of CTC and ANOPP codes. A digital engine performance model t was used to calculate

some of the needed parameters. Others were computed using follow-on calculations.

Engine Model Description

The F110-GE-129 engine performance model (also referred to as the engine deck) is a digital computer FORTRAN program which predicts engine parameters and performance consistent with a nominal

F 110-GE-129 engine. The aerothermodynamic model calculates the various engine operating parameters.

Many of these parameters would otherwise be difficult or impossible to measure because of the excessively high temperatures, inaccessibility of the area to instrumentation, or both.

Data Selection Procedure

Plots of selected flight parameters were compared with the times associated with the pilot call outs for

the selected inbound distance, the overhead point, and the selected outbound distance. Results revealed

that Mach number, altitude, A8, and PLA were the main parameters defining the quality of the data for a

test run. A PLA and A8, which were constant along with a constant or slowly accelerating Mach number

and a relatively constant altitude were needed. In the flight data tables, there are typically three data

points per flyover: one at the start point, one at the overhead point, and one at the end point.

Engine Model Inputs

The F110-GE-129 engine deck input parameters used for the analysis consist of altitude, Mach number, T1, and PLA. The aircraft total temperature probe was inoperative for the acoustics flights, and it was

planned to use the T1. For verification, the engine deck-calculated ambient temperature was compared

with the temperature measured by the AFFTC weather balloon at approximately the time of flights 1

and 3. Figure 7 compares the ambient temperatures calculated from the flight T1 measurement with the

weather balloon-measured data as a function of altitude. Standard day T1 is shown for reference. The

flight and balloon comparisons match well enough to justify the use of T1 in combination with aircraftcalculated Mach number and altitude.

*Wills, T. K., Cycle Deck User's Manual for F110-GE-129 Performance, GE R89AEB216, May 1989. (Contact General

Electric Company, Lynn, Massachusetts.)

12
Ambient

temperature,

°C

Ambient

temperature,

°C

14

12

10

8

• Flight 1

Temperatures

Standard day

• Weather ballon

[] Calculated

from airplane

measured T1

6 D"

4

o -- ___ []

-2

-4 I I 1 I I m I

20 -- Flight 3

15 -- • •__33 ANOPP points

10

5

0

-s I I I I I I • I

3 5 7 9 11 13 15 x 103

Altitude, ft 9soso6

Figure 7. Ambient temperature and standard day temperature for the acoustics flyover tests.

The engine deck uses Mach number and ambient pressure based on altitude to compute the free

stream total pressure. The inlet pressure recovery curve for the F-16XL, ship 2 (fig. 2(b)), was input into

the engine deck to provide the correct engine face pressure recovery.

13
Engine Model Output

The engine deck, models the engine as a gas generator and predicts output flight parameters based on

the measured airplane flight parameters which were previously input. Some of the unmeasureable

parameters that were calculated by the engine deck and were needed for the acoustic analysis were gross

thrust (Fg); Vjet; NPR; ratio of exhaust nozzle effective exit-plane area to its effective throat area, AE9/

AE8; ratio of exhaust nozzle flow exit-plane static pressure to ambient static pressure, Ps9/Pamb; exhaust

nozzle mixed-jet total temperature at the throat, T8; mass flow rate at the exhaust nozzle throat, W8; and

other useful exhaust nozzle exit stream parameters, such as throat total pressure, P8 and the specific heat

ratio of exhaust gas at nozzle entrance, GAM7. The engine deck also calculates parameters, such as

PT2.5, Ps3, WFE, N1, N2, and A8 which may be compared to the engine measurements.

In addition to the engine deck-calculated value of Vjet, the local values of V9, M9, and Mjet were

determined from later calculations.

Exhaust Flow Properties

For these calculations, steady, one-dimensional, adiabatic, isentropic flow was assumed to exist between the planes of the nozzle inlet (station 7) and the nozzle exit (station 9). One of three possible cases

is assumed to exist at the nozzle exit plane depending on the level of static pressure (Ps9) existing at the

moment of data sampling. If the condition (Ps9 < Pamb) exists, the flow is said to be overexpanded. If

the condition (Ps9 = Pamb) exists, the flow is said to be fully expanded. When the condition (Ps9 >

Pamb) exists, the flow is said to be underexpanded. In all cases, it is assumed that total temperature and

specific heat ratio of exhaust gas is equal at stations 7, 8, 9, and jet.

Ideal or Jet Expansion Parameters

One way to calculate exhaust properties is to assume that the total pressure at the nozzle throat is

isentropically expanded to atmospheric pressure. These jet parameters are independent of the nozzle

expansion ratio and are only a function of NPR. The Mjet parameter uses this assumption.

Area Ratio Parameters

M9 is another parameter of interest for acoustic analysis. This parameter is determined based entirely

on the ratio of the exhaust nozzle area at the exit plane to its area at the throat, A9/A8. It assumes that the

flow expands isentropically from the throat to the exit regardless of what the exit static pressure may be.

For the engine deck, an effective area ratio, AE9/AE8 is calculated and may be used to calculate M9. This

calculation is only useful for cases in which the flow at station 8 is choked.

Exhaust Static Temperature

The exhaust nozzle exit and fully expanded jet static temperatures, Ts9 and Tsjet, are calculated from

7'8 using GAM7 from the engine deck.

14
Local Speed of Sound and Exhaust Velocities

The speed of sound propagation in the hot gas stream was calculated using conventional gas dynamics relationships, then multiplied by the Mach number to arrive at the exhaust velocities. These calculations were performed in a follow-on program to supplement the engine deck outputs.

RESULTS AND DISCUSSION

The results of the ground run, CTC tests, and ANOPP tests are presented in tables 4, 5, and 6. Each

table shows first, in part (a), the measured input data and measured engine parameters; second, in part (b),

a comparison of the engine deck-calculated values to the engine measurements; and third, in part (c), the

engine deck and follow-on calculated exhaust parameters. For the flyovers, there are usually three data

points: one at the beginning of the run, one at the overhead point, and one at the end.

Table 4. F-16XL, ship 2, ground run test.

(a) Measured and engine deck-calculated parameters.

Mach number 0.0, pressure altitude = 2270 ft

Input to deck Deck output

Test PLA, Tamb, Pamb, T1, P1,

point deg °R lbf/in 2 °R lbffin 2

Measured engine parameters

PT2.5, Ps3, WFE, N1, N2, EGT, A8,

lbf/in 2 lbf/in 2 lb/h rpm rpm °R in 2

1 20.4 517.6 13.53 517.6 13.2 15.9 53 1179 3141 10354 1456 965

2 24.7 517.6 13.53 517.6 13.1 17.5 71 1587 3992 11126 1426 770

3 30.5 517.6 13.53 517.6 13.0 21.0 108 2513 5113 11899 1445 520

4 32.5 517.6 13.53 517.6 12.9 21.8 116 2663 5341 12062 1530 519

5 38.7 517.6 13.53 517.6 12.8 24.6 145 3481 6051 12529 1542 496

6 43.9 517.6 13.53 517.6 12.6 26.5 168 4062 6491 12846 1580 491

7 48.9 517.6 13.53 517.6 12.5 28.1 185 4578 6858 13117 1631 489

8 55.1 517.6 13.53 517.6 12.3 30.1 207 5310 7207 13445 1678 492

9 60.2 517.6 13.53 517.6 12.1 31.7 227 6042 7510 13765 1732 499

10 67.6 517.6 13.53 517.6 12.0 33.8 251 6882 7693 14033 1793 482

11 72.8 517.6 13.53 517.6 11.8 36.7 287 8197 7860 14339 1899 444

12 83.6 517.6 13.53 517.6 11.4 38.5 312 9427 8187 14663 1999 445

13 85.2 517.6 13.53 517.6 11.4 38.3 314 9385 8215 14710 1996 444

14 53.7 517.6 13.53 517.6 12.4 29.7 205 5116 7135 13414 1628 488

15 29.7 517.6 13.53 517.6 13.0 20.4 104 2276 4972 11859 1379 546

16 15.2 517.6 13.53 517.6 13.2 15.9 52 1201 3111 10400 1497 975

15
Table 4. Continued.

(b) Comparison of measured and engine deck-calculated engine parameters.

Test PLA, PT2.5, Ps3, WFE, N1, N2 A8,

point deg lbf/in 2 lbf/in 2 lb/h rpm rpm in2

Meas Deck Meas Deck Meas Deck Meas Deck Meas Deck Meas Deck

20.4 15.9 16.2 52.5 50.0 1179.1 1117 3141 3105 965 958

24.7 17.5 17.8 71.3 70.7 1587.3 1434 3992 3961 770 761

30.5 21.0 21.0 108.1 107.1 2512.9 2233 5113 5094 520 520

32.5 21.8 21.8 115.7 115.0 2663.4 2420 5341 5253 519 520

38.7 24.6 24.7 145.3 146.0 3480.9 3227 6051 6052 496 490

1

2

3

4

5

6

7

8

9

10

11

12

13

43.9

48.9

55.1

60.2

67.6

72.8

83.6

85.2

26.5 26.7 167.6 167.0 4061.8 3803 6491 6500

28.1 28.3 184.6 184.0 4578.1 4298 6858 6872

30.1 30.5 207.1 209.0 5309.9 5049 7207 7235

31.7 32.4 227.3 232.0 6041.9 5814 7510 7520

33.8 34.6 251.3 260.0 6881.9 6728 7693 7740

36.7 37.0 287.3 290.0 8196.8 7760 7860 7887

38.5 39.7 312.5 325.0 9427.0 9191 8187 8224

38.3 39.9 313.8 327.0 9384.8 9262 8215 8241

10354 10187

11126 11137

11899 11950

12062 12094

12529 12590

12846 12858 491 485

13117 13083 489 485

13445 13442 492 487

13765 13733 499 491

14033 14079 482 477

14339 14423 444 448

14663 14696 445 448

14710 14709 444 449

Table 4. Concluded.

(c) Deck output and calculated exhaust parameters.

Test PLA, P8, T8,

point deg lbffin 2 °R

Fg, W8, AE9/

GAM7 lbf lb/sec AE8

Exhaust properties

Station 9, f(A9/A8) Jet, f(NPR)

vg, Psg/ Vjet,

M9 ft/sec Pamb NPR Mjet ft/sec

1 20.4 13.8 852

2 24.7 14.2 848

3 30.5 16.7 918

4 32.5 17.1 929

5 38.7 19.4 991

6 43.9 21.0 1032

7 48.9 22.2 1065

8 55.1 24.0 1115

9 60.2 25.6 1165

10 67.6 28.2 1233

11 72.8 31.9 1321

12 83.6 34.6 1411

13 85.2 34.7 1415

14 53.7 23.5 1101

15 29.7 16.3 906

16 15.2 13.8 852

1.386

1.387

1.382

1.381

1.377

1.374

1.372

1.368

1.364

1.359

466 67.4 1.298 - - - 1.019 0.173 232

1028 89.1 1.261 - - - 1.053 0.279 385

2753 114.9 1.121 - - - 1.233 0.561 800

3079 121.2 1.121 - - - 1.263 0.594 849

4537 140.2 1.100 1.372 1804.1 0.47 1.436 0.746 1082

5498 151.9 1.096 1.362 1831.0 0.52 1.550 0.826 1210

6302 161.3 1.096 1.362 1859.3 0.55 1.642 0.882 1302

7426 173.2 1.097 1.364 1904.7 0.59 1.770 0.952 1423

8478 153.6 1.100 1.368 1950.9 0.63 1.890 1.011 1529

9732 191.5 1.090 1.348 1984.8 0.72 2.088 1.095 1682

1.353 11049 195.3 1.068 1.300 1998.4 0.87 2.360 1.194 1867

1.347 12626 206.8 1.070 1.305 2070.6 0.94 2.559 1.258 2009

1.346 12696 207.3 1.071 1.307 2076.4 0.94 2.567 1.261 2015

1.369 7133 170.2 1.097 1.360 1888.8 0.58 1.737 0.935 1392

1.383 2503 111.7 1.132 - - - 1.203 0.527 748

1.386 457 67.5 1.300 - - - 1.018 0.170 227

16
Table5. CTCtestdata.

(a)CTCmeasuredandinput to deckdata.

Measuredandcalculated

inputstodeck Calculatedby deck Measured engine data

PLA, Mach Altitude, T1, Tamb, Pamb, P1, PT2.5, Ps3, WFE, N1, N2, EGT, A8,

Test Segment deg number ft °R °R lbf/in 2 lbf/in 2 lbf/in 2 lbf/in 2 lb/h rpm rpm °R in2

A Start 85.0 0.344

A OH 85.0 0.557

A End 85.0 0.758

B Start 85.1 0.622

B OH 85.0 0.852

B End 85.0 0.945

C OH 85.0 0.684

C End 85.0 0.946

D Start 85.1 0.329

D OH 85.1 0.563

D End 85.1 0.755

3565 520.9 508.9 12.90 13.72 45.6 381 10789 8305 14686 1846 446

3610 538.5 507.1 12.88 15.58 53.2 440 12911 8470 14936 2153 446

3603 563.4 505.3 12.89 18.47 61.8 500 14654 8536 15060 2027 447

7042 540.1 501.3 11.32 14.18 49.3 410 12071 8470 14887 1920 446

7040 569.6 497.4 11.32 17.83 58.9 477 13869 8547 15044 2156 447

7035 585.5 496.8 11.33 19.73 63.1 501 14853 8566 15029 2190 447

11975 543.4 496.9 09.36 12.54 42.6 356 10724 8486 14866 1998 445

12060 581.3 493.1 09.32 16.26 52.5 422 12442 8556 15044 2160 447

3498 521.3 510.3 12.93 13.66 44.9 376 11033 8300 14607 1821 446

3540 541.6 509.3 12.91 15.69 53.7 447 13005 8492 14960 2130 446

3558 563.6 486.1 12.90 18.45 61.4 499 12957 8520 15094 2136 446

Table 5. Continued.

(b) Comparison of measured and deck-calculated engine parameters.

PLA, Mach PT2.5, Ps3, WFE,

Test Segment deg number lbf/in 2 lbf/in 2 lb/h

N1, N2, A8,

rpm rpm in2

A Start

A OH

A End

B Start

B OH

B End

C OH

C End

D Start

D OH

D End

Meas Deck Meas Deck Meas Deck Meas Deck Meas Deck Meas Deck

85.0 0.344 45.6 47.9 381 395 10789 11099 8305 8295 14686 14775 446 450

85.0 0.557 53.2 55.0 440 456 12911 13161 8470 8469 14936 15034 446 451

85.0 0.758 61.8 63.0 500 511 14654 14797 8536 8535 15060 15098 447 452

85.1 0.622 49.3 50.9 410 420 12071 12173 8470 8476 14887 15049 446 450

85.0 0.852 58.9 59.9 477 482 13869 13834 8547 8542 15044 15039 447 452

85.0 0.945 63.1 64.2 501 508 14853 14609 8566 8561 15029 15078 447 452

85.0 0.684 42.6 44.1 356 392 10724 10577 8486 8490 14866 15066 445 450

85.0 0.946 52.5 53.7 422 456 12442 12357 8556 8556 15044 15074 447 447

85.1 0.329 44.9 47.6 376 392 11033 11020 8300 8287 14607 14772 446 449

85.1 0.563 53.7 55.3 447 456 13005 13208 8492 8482 14960 15057 446 451

85.1 0.755 61.4 64.4 499 529 14700 15215 8520 8482 15094 15009 446 452

17
Table 5. Concluded.

(c) CTC deck and calculated parameters.

PLA, Mach P8, T8, W8, Fg, AE9/

Test Segment deg number Ibf/in 2 °R GAM7 Ib/sec lb AE8

Exhaust characteristics

Station 9, f(AE9/AE8) Jet, f(NPR)

V9, Ps9/ Vjet,

M9 ft/sec Pamb NPR Mjet ft/sec

A

A

A

B

B

B

C

C

D

D

D

Start 85.0 0.344 41.8 1422 1.346 248.5 16793 1.199 1.520 2328 0.88 3.24 1.428 2223

OH 85.0 0.557 48.2 1480 1.342 280.5 20401 1.224 1.553 2412 0.96 3.74 1.528 2382

End 85.0 0.758 54.4 1488 1.342 319.3 24189 1.224 1.553 2419 1.09 4.22 1.610 2478

Start 85.1 0.622 44.5 1484 1.342 258.7 19145 1.223 1.553 2415 1.01 3.93 1.562 2422

OH 85.0 0.852 51.2 1481 1.343 304.2 23416 1.224 1.553 2413 1.17 4.52 1.656 2519

End 85.0 0.945 54.4 1484 1.342 325.2 25462 1.224 1.553 2416 1.24 4.80 1.696 2562

OH 85.0 0.684 38.5 1489 1.342 224.2 16852 1.223 1.552 2418 1.06 4.11 1.593 2460

End 85.0 0.946 46.0 1496 !.342 269.9 21343 1.221 1.549 2421 1.28 4.93 1.713 2590

Start 85.1 0.329 41.6 1421 1.346 247.1 16647 1.194 1.510 2317 0.88 3.22 1.423 2216

OH 85.1 0.563 48.3 1493 !.342 281.2 20488 1.224 1.553 2423 0.97 3.74 1.529 2386

End 85.1 0.755 55.7 1466 1.343 330.8 25016 1.224 1.553 2401 1.11 4.32 1.625 2474

Table 6. ANOPP flyover test data.

(a) ANOPP flyover measured input data to deck.

Engine data

Measured and calculated

inputs to deck Calculated by deck Measured engine parameters

PLA Mach Altitude, T1, Tamb, Pamb, P1, PT2.5, Ps3, WFE, N1, N2, EGT, A8,

Test Segment deg number ft °R °R lbf/in 2 lbf/in 2 lbf/in 2 lbf/in 2 lb/h rpm rpm °R in 2

E Start 48.5 0.308

E OH 48.5 0.300

E End 48.5 0.282

F Start 35.1 0.603

F OH 35.1 0.601

F End 34.8 0.605

G Start 46.6 0.793

G OH 46.6 0.804

G End 46.6 0.814

H Start 55.5 0.946

H OH 55.6 0.955

H End 55.5 0.947

3783 530.0 520.1 12.79 13.40 30.3 201.1 4736 6948 13314 1620 478

3730 530.3 520.9 12.82 13.37 30.1 200.0 5285 6936 13304 1608 480

3648 529.1 520.8 12.86 13.31 29.9 198.5 4619 6937 13290 1607 478

3780 558.6 520.7 12.80 16.03 31.8 194.2 4360 6396 13321 1576 463

3740 559.0 521.3 12.82 16.03 31.8 193.8 4332 6388 13316 1579 463

3750 561.3 523.0 12.81 16.08 31.8 194.0 4332 6381 13318 1565 459

3728 584.5 519.2 12.82 19.02 43.5 289.3 7148 7317 14069 1741 469

3735 586.5 519.4 12.82 19.23 43.8 291.1 7221 7306 14064 1741 469

3770 589.1 520.2 12.80 19.39 43.8 293.2 7185 7308 14079 1757 468

3753 610.9 518.2 12.81 22.34 54.8 379.8 9992 7815 14576 1882 471

3745 611.8 517.5 12.81 22.57 55.3 382.0 9864 7823 14590 1747 474

3742 611.8 518.8 12.82 22.37 54.8 379.5 9864 7806 14576 1719 472

18
Table 6. Continued.

(b) Comparison of measured and deck-calculated parameters.

PLA, Mach PT2.5, Ps3, WFE, N1, N2, A8,

Test Segment deg number lbf/in 2 lbf/in 2 lb/h rpm rpm in 2

E Start

E OH

E End

F Start

F OH

F End

G Start

G OH

G End

H Start

H OH

H End

Meas Deck Meas Deck Meas Deck Meas Deck Meas Deck Meas Deck

48.5 0.308 30.3 30.0 201.1 195.4 4736 4506 6948 6927 13314 13219 478 476

48.5 0.300 30.1 30.0 200.0 195.0 5285 4497 6936 6926 13304 13221 480 476

48.5 0.282 29.9 29.9 198.5 194.1 4619 4472 6937 6918 13290 13206 478 476

35.1 0.603 31.8 31.9 194.2 190.0 4360 4229 6396 6344 13321 13101 463 458

35.1 0.601 31.8 31.9 193.8 190.0 4332 4227 6388 6345 13316 13104 463 458

34.8 0.605 31.8 31.7 194.0 188.0 4332 4182 6381 6319 13318 13103 459 458

46.6 0.793 43.5 43.8 289.3 288.0 7148 6922 7317 7288 14069 13895 469 458

46.6 0.804 43.8 44.2 291.1 290.0 7221 6981 7306 7290 14064 13911 469 457

46.6 0.814 43.8 44.5 293.2 291.0 7185 7022 7308 7292 14079 13932 468 456

55.5 0.946 54.8 55.3 379.8 381.0 9992 9722 7815 7803 14576 14490 471 467

55.6 0.955 55.3 55.9 382.0 385.0 9864 9834 7823 7809 14590 14497 474 468

55.5 0.947 54.8 55.3 379.5 381.0 9864 9719 7806 7804 14576 14492 472 467

Table 6. Concluded.

(c) ANOPP test engine deck and calculated outputs.

PLA, Mach P8, T8, Fg,

Test Segment deg number lbf/in 2 °R GAM7 lb

Exhaust conditions

Station 9, f(AE9/ Jet, f(NPR)

AE8)

W8, AE9/ V9, Ps9/ Vjet,

lb/sec AE8 M9 ft/sec Pamb NPR Mjet ft/sec

E Start

E OH

E End

F Start

F OH

F End

G Start

G OH

G End

H Start

H OH

H End

48.5 0.308 23.58 1078 1.371 7400 170 1.089 1.35 1859 0.63 1.843 0.985 1444

48.5 0.300 23.53 1078 1.371 7363 169 1.090 1.35 1859 0.63 1.836 0.981 1440

48.5 0.282 23.43 1076 1.371 7288 169 1.090 1.35 1857 0.62 1.822 0.975 1430

35.1 0.603 25.14 1057 1.373 7934 175 1.076 1.32 1810 0.70 1.965 1.039 1496

35.1 0.601 25.13 1058 1.373 7918 175 1.076 1.32 1810 0.70 1.961 1.038 1494

34.8 0.605 25.00 1058 1.373 7840 174 1.076 1.32 1811 0.69 1.952 1.034 1490

46.6 0.793 34.93 1188 1.363 13499 235 1.104 1.37 1973 0.91 2.724 1.298 1893

46.6 0.804 35.24 1191 1.363 13665 236 1.108 1.38 1986 0.90 2.749 1.305 1902

46.6 0.814 35.46 1194 1.364 13787 237 1.112 1.39 1999 0.90 2.770 1.310 1911

55.5 0.946 44.10 1290 1.356 19093 290 1.237 1.53 2227 0.91 3.443 1.468 2160

55.6 0.955 44.57 1292 1.356 19373 293 1.237 1.53 2229 0.92 3.478 1.475 2169

55.5 0.947 44.11 1291 1.356 19091 290 1.237 1.53 2228 0.91 3.442 1.468 2160

Verification of F110-GE-129 Engine Deck

Use of the F 110-GE-129 engine deck, which represents a nominal engine, could introduce errors if

the flight test engine were significantly different from the assumed nominal engine. To assess such potential errors, a comparison of some engine-measured parameters with calculated parameters from the

19
engine deck was made. Tables 4(b), 5(b), and 6(b) compare the airplane-measured parameters with the

engine deck-calculated parameters. There are six measured engine parameters (in addition to the PLA,

T1, altitude, and Mach number that are inputs to the engine deck) that may be compared with engine

deck-calculated parameters. These are N1, N2, PT2.5, Ps3, WFE, and A8. Inspection of these tables

shows very good agreement for these comparisons, indicating that the engine deck is a good representation of the engine flown in the F-16XL, ship 2. Plots of the comparisons are shown in figure 8 for the

ground run, figure 9 for the CTC tests, and fig 10 for the ANOPP tests. The ground run, CTC, and

ANOPP flyover data show good to excellent agreement between measured and calculated

engine parameters.

PT2.5,

Ibf/in 2

40 400

3O

2O

I0

300

Ps3, 200

Ibf/in 2

100

I I o

Parameters

[] Deck calculation

• Measured

Fuel flow,

Ib/hr

10,000

8,000

6,000

4,000

2,000

0

i I

N1,

rpm

10,000

8,000

6,000

4,000

2,000

0

I I

15,000 1000800f __;

14,000

600

rpm 12,000 A8, I I

in2 400 --

10,000

200

8,ooo I I I

0 50 100 0 50 100

PLA, dag PLA, deg 9_oo7

Figure 8. Comparison of measured and deck-calculated parameters, ground run.

20
PT 2.5,

Ibf/in 2

70

65

60

55

5O

45

40

35

30

_3,500 ft r-_

altitude --_

-- altitude

I f I

570

520

470

Ps 3, 420

Ibf/in2 370

320

27O

220

Parameters

D Deck calculation

• Measured

m

3,500 ft

altitude__

-- _7,000"_ ! _ l:;O0:dfte

altitude

I 1 I I

16,000

14,000

WFE, 12,000 Ib/sec

10,000

8,000

r 3,500 ft _ •

altitude--_

N1,

rpm

8600 --

8550 --

8500 --

8450 --

8400 --

8350 --

8300 _

8250 I I I I

N2,

rpm

15,100 _ _['-][-'] [_]mm[] _ 14,600

14,1 O0

13,600

A8,

in 2

48o

450

440

430 n

420 --

410

.3

13,100 I I I I I I I I

.3 .5 .7 .9 1.1 .5 .7 .9 1.1

Mach number Mach number

960608

Figure 9. Comparison of measured and deck-calculated parameters, climb-to-cruise tests.

21
PT2.5,

Ibf/in 2

WFE,

Ib/hr

60

50

40

30

20

10

0

10,000

8,000

6,000

4,000

2,000

0

!

B @

Ps3,

Ibf/in 2

N1,

_ rpm

I I

400 --

300--

200 --

100 --

0

8000--

6000 --

4000 --

2000--

0

Parameters

[] Deck calculation

• Measured

I I

I I

N2,

rpm

15,000

14,500

14,000

13,500 m

A8, in 2

5O(:)

480

460

440

420

4OO

D

e, e

13,ooo I I I

0 .50 1.0 0 .50 1.0

Mach number Mach number

96o6o9

Figure 10. Comparison of measured and deck-calculated parameters, ANOPP tests.

Another indication of the quality of these engine deck data may be inferred from figure 7 which

shows temperatures of no more than 10 °C from standard day temperature and not much variation for the

2 test days. Cycle decks tend to be less accurate as deviations from standard day temperature (where

much of the cycle deck data were obtained) increase.

22
Ground Static Test Results

The ground static run data are listed in table 4 for the range of power settings from idle to intermediate. Note that the nozzle is unchoked below a PLA of 38 ° and is overexpanded for all ground conditions.

Maximum NPR is 2.57 at intermediate power.

Figure 11 plots these values for Mjet and M9 versus PLA for the test points where the flow is choked.

The M9 and Mjet are separated at the lower values of PLA and approach each other at the higher PLA

where the nozzle is only slightly overexpanded. The corresponding values of V9 and Vjet are also plotted

showing similar trends to the Mach numbers.

Exhaust

Mach

number

1.4

1.2

1.0

.8

k

m

m

B 6 B

.2

0

[] Nozzle exit, station 9

• Fully expanded jet

2500

2OOO

Exhaust 1500

velocity,

ft/sec

m

m

1000 -- O

I I

0 20 40 60 80 100

PLA, deg _o61o

Figure 11. Exhaust flow properties, F110-GE-129 engine in F-16XL, ship 2, ground run.

Flyover Exhaust Flow Properties Results

For most flyover tests, three data points per run are shown: the initial data at the beginning of the run,

a point over the microphone array, and the last point at the end of the data run. Table 3 shows a summary

of the flyover tests from the three flights. The airplane accelerated rapidly for the CTC tests, while the

ANOPP tests were at nearly constant Mach number.

CTC Test Results

Table 5 shows the measured and calculated parameters for the CTC tests. In all cases, the airplane

accelerated significantly during the run. Values of NPR varied from 3.2 to almost 5.

23
Figure12showsM9, and Mjet for the CTC conditions and compares both the exhaust Mach numbers

and velocities versus the aircraft free stream Mach number. Conditions shown in figure 12 are at intermediate power (PLA = 85 °) and at nominal altitudes ranging from 3,800 to 12,300 ft. Because the nozzle

area is essentially constant at intermediate power, A9/A8 does not vary significantly; therefore, M9 is

almost constant at a value of 1.55. At the lower aircraft Mach numbers (below Mach 0.6), the nozzle flow

is overexpanded as it was in the ground run, so Mjet < M9. Above Mach 0.6, the nozzle is underexpanded,

and Mjet > M9. The effects of altitude were quite small as would be expected for V9 and Vjet. Figure 12

shows a similar trend.

1.75 --

1.70 --

1.65

Exhaust

Mach 1.60 --

number 1.55-

1.50 _]

1.45 --

1.40 •

2600 --

2550 --

2500 --

Exhaust 2450 --

velocity, 2400 --

Wsec

2350

2300 _]

2250 i

2200

.3

l Mjet

[] rlM9

L I I I

V jet

ii B

[] Cjv,

[] Nozzle exit, station 9

• Fully expanded jet

1 I I I

.5 .7 .9 1.1

Free stream Mach number

960611

Figure 12. Exhaust flow properties, F110-GE-129 engine in F-16XL, ship 2, climb-to-cruise tests, all

tests at intermediate power, for altitudes, see table 5.

ANOPP Test Results

Table 6 lists ANOPP test data from flight 3. The flight points were near an altitude of 3800 fl (1500 ft

AGL) and were started two miles before and ended two miles past the microphone array. The PLA was

fixed at PLF. Because of the lower power settings, ANOPP test NPR values varied from 1.8 to 3.4. A significant variation also existed in PLA, so the A9/A8 parameter varied; hence, M9 varied from 1.32 to 1.53.

Figure 13 shows the exhaust Mach number and velocity as a function of airplane Mach number. The

M9 is higher than Mjet (fig. 13(a)) because the flow is overexpanded at all conditions. Similarly, V9 is

higher than Vjet. At the higher Mach number conditions, the nozzle flow is only slightly overexpanded.

24
Exhaust

Mach

number

1.6

1.5

1.4

1.3

1.2

1.1

1.0

.9

.8

n_

I I I I

•[] Nozzle Fully expanded exit, stationjet 9

2400

2200

2000

Exhaust 1800

velocity,

ft/sec 1600

1400

1200

1000

[]

--ira •

I I

.2 .4 .6 .8 1.0

Free stream Mach number

960612

I I

Figure 13. Exhaust flow properties, F110-GE-129 engine in F-16XL, ship 2, ANOPP tests, 3800 ft altitude.

CONCLUDING REMARKS

Flyover and static tests of the F-16XL, ship 2, airplane, powered by the GE F110-GE-129 engine,

were conducted as part of a joint NASA Dryden and NASA Langley program to study the acoustics of

high nozzle pressure ratio engines. An engine cycle deck was used to calculate parameters for comparison with measured parameters. The engine deck and follow-on calculations were also used to calculate

exhaust properties where measurements were not possible. Very good agreement was found between

cycle deck-calculated and measured engine parameters. Such agreement gives good confidence in the

calculated exhaust properties. Nozzle pressure ratios up to almost 5 occurred at intermediate power, with

a maximum jet Mach number of 1.7 and maximum jet velocity of nearly 2600 ft/sec. Nozzle conditions

ranged from underexpanded to overexpanded, depending on flight conditions.

Dryden Flight Research Center

National Aeronautics and Space Administration

Edwards, California, August 1996

25
REFERENCES

1. Zorumski, William E., Aircraft Noise Prediction Program Theoretical Manual, NASA TM-83199,

Part 1, 1982.

2 Ennix, Kimberly A., Burcham, Frank W., and Webb, Lannie D., Flight-Determined Engine Exhaust

Characteristics of an F404 Engine in an F-18 Airplane, NASA TM-4538, 1993.

3 Ennix, Kimberly A., Engine Exhaust Characteristics Evaluation in Support of Aircraft Acoustic

Testing, NASA TM-104263, 1993.

26

R EPO RT DOCU M E NTATIO N PAG E FormApproved

OMB No. 0704-0188

Pubhc reporting burden for this collection of information is eslimated to average I hour per response, including the time for reviewing instructions, searching existing data sources

gatheringand maintainingthe data needed, and completingand reviewingthecollectionofinformation.Send comments regardingthisburden estimateor any otheraspect ofthiscollectionof information,includingsuggestionsforreducingthisburden, IoWashington Headquarters Services,DirectorateforInfqrmationOperations and Reports. t215 JeffersonDavis

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORTTYPE AND DATES COVERED

November 1996 Technical Memorandum

4. TITLE AND SUBTITLE

Flight and Static Exhaust Flow Properties of an F110-GE-129 Engine in an

F-16XL Airplane During Acoustic Tests

6. AUTHOR(S)

Jon K. Holzman, Lannie D. Webb, and Frank W. Burcham, Jr.

7.PERFORMINGORGANIZATIONNAME(S) ANDADDRESS(ES)

NASA Dryden Flight Research Center

P.O. Box 273

Edwards, California 93523-0273

9.SPONSORING/MONITORING AGENCYNAME(S)ANDADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

5. FUNDING NUMBERS

WU 505-68-10

8. PERFORMING ORGANIZATION

REPORT NUMBER

H-2122

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

NASA TM- 104326

11.SUPPLEMENTARYNOTES

12a. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified--Unlimited

Subject Category 07

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

The exhaust flow properties (mass flow, pressure, temperature, velocity, and Mach number) of the

F110-GE-129 engine in an F-16XL airplane were determined from a series of flight tests flown at

NASA Dryden Flight Research Center, Edwards, California. These tests were performed in conjunction with NASA Langley Research Center, Hampton, Virginia (LaRC) as part of a study to investigate

the acoustic characteristics of jet engines operating at high nozzle pressure conditions. The range of

interest for both objectives was from Mach 0.3 to Mach 0.9. NASA Dryden flew the airplane and

acquired and analyzed the engine data to determine the exhaust characteristics. NASA Langley collected the flyover acoustic measurements and correlated these results with their current predictive

codes. This paper describes the airplane, tests, and methods used to determine the exhaust flow properties and presents the exhaust flow properties. No acoustics results are presented.

14. suaJ ECT TERMS

Acoustics; F110 engine; F-16XL airplane; Flyover noise

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION

OF REPORT OFTHIS PAGE OF ABSTRACT

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NSN 7540-01-280-5500 Available from the NASA Center for AeroSpace Information, 800 Elkridge Landing Road,

Linthicum Heights, MD 21090; (301)621-0390

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32

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