pt6a engine testing

PT6A SERIES ENGINE TESTING

1

PREPARED BY : JOKO ISMIYANTO

PT. NUSANTARA TURBIN & PROPULSI

2013

PT6A SERIES ENGINE TESTING

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TABLE OF CONTENT

1. ENGINE TEST FLOW CHART …………………………………………………………………. 3

2. TEST REQUIREMENT AND PROCEDURE MATRIX …………………….……………………. 5

3. LIST OF PT6A PARAMETER AND SYMBOL …………………….……………………. 6

4. TEST PROCEDURE SEQUENCE …………………….……………………. 7

5. ENGINE TEST OPERATING CONDITION LIMIT …………………….……………………. 9

6. ENGINE MOTORING, STARTING AND SHUT DOWN …………………….……………………. 10

7. RUN IN PROCEDURE …………………….……………………. 12

8. ACCESSORIES GEARBOX (AGB) VIBRATION SURVEY …………………….……………………. 13

9. REDUCTION GEARBOX (RGB) VIBRATION CHECK …………………….……………………. 15

10. ACCELERATION AND BODIE CHECK …………………….……………………. 16

11. TT5 TRIM DETERMINATION …………………….……………………. 21

12. ACCEPTANCE CHECK (PERFORMANCE) …………………….……………………. 26

13. CONTROL SETTING : MAXIMUM NG ADJUSTMENT …………………….……………………. 56

14. CONTROL SETTING : MINIMUM FUEL FLOW CHECK …………………….……………………. 60

15. POST TEST RUN CHECK …………………….……………………. 64

16. UNUSUAL OIL CONDITION …………………….……………………. 66

PT6A series engine testing

INSPEKSI VISUAL DAN CEK KELENGKAPAN

DOKUMEN

START

PREPARASI ENGINE & FASILITAS

QI TC17-002

QI TC17-002 danOVERHAUL MANUAL

CHECK ENGINE & FASILITAS TEST :• CEK KEWAJARAN NILAI ZERO

READING PARAMETER• CEK SISTEM PROTEKSI• CEK FUNGSI KONTROL DYNO

TEST ENGINEQI TC17-002 danOVERHAUL MANUAL

ENGINE TEST PROCESS FLOW CHART

ENGINE & DOKUMEN KOMPLIT

KONTAK PPC

TIDAK

YA

FASILITAS TEST

NORMAL

KONTAK FUNGSI

ETS

TIDAK

YA

EVALUASI HASIL TEST

A



3


BELLMOUTH & EXHAUST CHECK

A

DE-PREPARASI ENGINE

LENGKAPI DOKUMEN TEST

KONTAK PPC

FINISH




ENGINE TEST PROCESS FLOW CHART

4


TEST REQUIREMENT & PROCEDURE MATRIX

PARAGRAF NO.

PROCEDURE ENGINEGAS

GENERATOR

POWER SECTIO

N

1 General X X X

2 Consumable material X X X

3 Special tools X X X

4 Fixtures, equipment and supplier tools X X X

5 Engine test equipment X X X

7 Symbols X X X

8 Preparation for test X X X

9 Engine motoring, starting & shut down X X X

10A LIMITS X X X

10D Preliminary check X X X

10E AGB vibration survey X X

10G Acceleration and Bodie check X X

10H TT5 trim determination X X

10I Acceptance check / performance check X X

10J Acceptance Value X X

11A Control setting : Minimum Governor check X X

11BControl setting : Propeller Governor maximum speed X X

11CControl setting : Underspeed fuel governing check X X

11D Control setting : Maximum NG adjustment X X

11E Control setting : Minimum Fuel Flow Check X X

12 Post test run check X X

13 Unusual oil condition X

14 Preservation X X

15 Removal of test equipment X X X

18 Final check X X X

19 Power section run – in XNote : The vibration survey requirement applies only to engine being tested following overhaul or repair requiring balancing of the compressor rotor assembly

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LIST OF PT6A PARAMETER AND SYMBOL

During static condition / engine not running / zero reading ,the normal reading for parameters are listed below:

SYMBOLSPARAMETER NAME

NORMAL VALUE @ ZERO READING

COMPUTER OHM VALUE UNIT DYNOSP Dyno speed 0 rpmWFPPH Wf Fuel flow 0 pphNGPER Gas generator speed in percent 0 %

NG Ng Gas generator speed in radian per minute 0 rpmNFPER Power turbine speed in percent 0 %

NF Nf Power turbine speed in radian per minute 0 rpmTT11 Engine inlet temperature no 1 70 - 87 deg fTT12 Engine inlet temperature no 2 70 - 87 deg fTT13 Engine inlet temperature no 3 70 - 87 deg fTT14 Engine inlet temperature no 4 70 - 87 deg fTT1A Tt1 Engine inlet temperature average 70 - 87 deg fTT5 Tt5 Interturbine temperature 70 - 87 deg f

TT71 Engine exhaust nozzle temperature no. 1 70 - 87 deg fTT72 Engine exhaust nozzle temperature no. 2 70 - 87 deg fTT73 Engine exhaust nozzle temperature no. 3 70 - 87 deg fTT74 Engine exhaust nozzle temperature no. 4 70 - 87 deg fTT75 Engine exhaust nozzle temperature no. 5 70 - 87 deg fTT76 Engine exhaust nozzle temperature no. 6 70 - 87 deg fTT77 Engine exhaust nozzle temperature no. 7 70 - 87 deg fTT78 Engine exhaust nozzle temperature no. 8 70 - 87 deg f

TT7A Tt7 Engine exhaust nozzle temperature average 70 - 87 deg fTFUEL Tf Fuel temperature 70 - 87 deg fTOILIN Oil temperature 70 - 87 deg fTOILSC Scavenge Oil temperature 70 - 87 deg fPBARO Pam Ambient Barometric Pressure 13.3 - 13.5 psia

PS1 Psn Test cell static pressure same with pbaro psiaPS3 Ps3 Compressure discharge static pressure 0 psig

PGEAR Prgb Reduction Gearbox Static Pressure 0 psigMOP Main Oil Pressure 0 psig

POILSC Scavenge Oil pressure 0 psigTORQ2 Engine Torquemeter Pressure 0 psig

TORQ2S Pam Engine Torquemeter Static Pressure 0 psig

DELP ∂P Delta TORQ2 - TORQ2S TORQ2 - TORQ2S psigVBGEA Gearbox vibration 0 G'sTORQ1 Dyno torque 0 ft lbsTHETA TH THETA 0.92 - 1.053

THETAR RTH Ѵ THETA (AKAR THETA) 1.01 - 1.03DELTA DEL DELTA (PBARO (inHg)/29.921) 0.905 - 0.918

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ENGINE MOTORING, STARTING & SHUTDOWN

RUN-IN PROCEDURE

PRELIMINARY CHECK :1. OBTAIN NF/RTH = 33000 RPM2. PERFORM 2 FEATHERING OPERATION3. OIL PRESSURE CHECK

AGB VIBRATION SURVEY

IF ASSUMED THAT ENGINE TREATED AS OVERHAUL AND COMPRESSOR ROTOR HAVEBEEN BALANCING, THEN TEST PROCEDURE SEQUENCE IS:

START

RGB VIBRATION CHECK

ACCELERATION & BODIE CHECK

TT5 TRIM DETERMINATION

A

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ACCEPTANCE CHECK / PERFORMANCE

MINIMUM GOVERNOR CHECK

PROPELLER GOVERNOR MAXIMUM SPEED

IF ASSUMED THAT ENGINE TREATED AS OVERHAUL AND COMPRESSOR ROTOR HAVEBEEN BALANCING, THEN TEST PROCEDURE SEQUENCE IS:

UNDERSPEED FUEL GOVERNING CHECK

MAXIMUM NG ADJUSTMENT

MINIMUM FUEL FLOW CHECK

A

POST TEST RUN CHECK

FINISH

PRESERVATION

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ENGINE TEST OPERATING CONDITION LIMIT

PARAMETER

MAXIMUM OPERATINGCONDITION

LIMIT

PT6A-21 PT6A-27/28 PT6A-25

NG (rpm)Steady State

38,100 (101.7%)

38,100 (101.7%)

38,100 (101.7%)

Acceleration38,500

(102.75%)38,500

(102.75%)38,500

(102.75%)

NF (rpm)Steady State

34,200 (103.6%)

34,200 (102.9%)

34,200 (103.6%)

Acceleration*36,300 (110%)

36300 (109.2%)

36,300 (110%)

TT5 (deg F)

Start 1350 1440 1350

Steady State (trimmed) 1283 1380 1283

Steady State (untrimmed) 1325 1400 1325

delP (inHg)Steady State 92 125 94

Acceleration* 94 127 94

NOTE : Rundown time on the compressor from ground-idle must not be < 20 seconds

*2 second time limit

SUPPLEMENTARY LIMITATION

PARAMETER LIMIT

Fuel pressure @ engine inlet all time including transient 5 - 20 psig

Oil temperature for all running except transient 140 - 160 deg F

Scavenge oil b ack pressure @ engine outlet 20 - 50 psigMaximum permitted difference between individual inlet temp. indication 8:F

Maximum permitted difference between average Tt7 thermocouple reading between each exhaust nozzle assembly 60:F

Maximum permitted difference between thermocouple within a given nozzle 100:F

Maximum operating vibration limit 100 G's

Maximum acceptance vibration limit 70 G's

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ENGINE MOTORING, STARTING & SHUT DOWN

WET MOTORING RUN

IF FIRE CONDITIONS OCCURS WITHIN ENGINE DURING MOTORING RUN , IMMEDIATELY CLOSE FUEL SHUTOFF VALVE

AND CONTINUE MOTORING ENGINE

ALLOW SUFFICIENT STARTER COOLING PERIOD BETWEENMOTORING CYCLES AND ENGINE START; REFER TO STARTERMANUFACTURERS LIMITS AND RECOMMENDATIONS.

DRY MOTORING RUN

This procedure is used to remove internally trapped fuel and fuel vapor, or ifthere is evidence of fire within the engine. Air passing through the engineserves to purge fuel/fuel vapor from the combustion section, power turbine andexhaust system.

ENGINE STARTING

ALLOW SUFFICIENT STARTER COOLING PERIOD BETWEENMOTORING CYCLES AND ENGINE START; REFER TO STARTERMANUFACTURERS LIMITS AND RECOMMENDATIONS.

THE ENGINE MUST START AND REACH IDLE WITHIN 35 SECONDS OF INITIATION OF THE START. THE FIRST START OF THE DAY CAN SOMETIMES TAKE LONGER; THEREFORE, THE START TIME MUST BE CORRECTED TO COMPENSATE FOR LONG TIME TO LIGHT. FOR TTL GREATER THAN 3 SECONDS: TTI MODIFIED = TTI RECORDED - (TTL – 3 SECONDS). IF THIS REQUIREMENT IS NOT ACHIEVED, check the FCU pneumatic system for leaks. If no leaks are found, replace the FCU.

IF Tt5 OBSERVED EXCEEDS 1440°F OR CONTINUOUS FLAME ISSUESFROM EXHAUST, SHUT OFF START CONTROL LEVER IMMEDIATELY.DO NOT ATTEMPT TO RELIGHT ON RUNDOWN; WAIT UNTIL THEENGINE COMES TO REST, THEN IMPLEMENT A DRY MOTORING CYCLETO COOL THE ENGINE

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ENGINE MOTORING, STARTING & SHUT DOWN

SHUT DOWN

IF A FIRE OCCURS IN THE ENGINE AFTER SHUTDOWN, DO A DRYMOTORING RUN IMMEDIATELY

For normal shut down, allow engine to run at ground idle for at least one minute to stabilize at minimum running temperatures.

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RUN-IN PROCEDURE

NOTE : This procedure is to be done after scheduled or unscheduled overhaul/repair has been completed.

1) Do a wet motoring run followed with a dry motoring run.

2) Start the engine and run at ground-idle 19750 ± 500 rpm Ng (propeller testing) or rotate dynamometer controller to obtain 5000 rpm Nf or maximum available (dynamometer testing) for 5 minutes.

3) Record Ng, Nf, Tt1, Tt5, del P, oil pressures and oil temperatures.

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NOTE: 1. The vibration survey requirement applies only to engines being tested following overhaul or repair requiring balancing of the compressor rotor assembly.

1) Select ‘‘Acceleration Survey’’ from the menu on the analyzer.

2) Set power control lever to GROUND-IDLE.

3) Set propeller control lever to 33000 rpm Nf.

NOTE: 2. Do the vibration survey using the following procedures and the ACES Operator’s Manual. Personnel must be familiar with the Analyzer prior to performing these operations.

CAUTION: DO NOT EXCEED ENGINE OPERATING LIMITS. ENGINEOPERATING LIMITS SUPERSEDE ANY INSTRUCTION IN ACESANALYZER PROCEDURE.

ACCELERATION SURVEY

4) Ng Sweep:

a) Press ‘‘Enter’’ on the analyzer to start recording.

b) Accelerate slowly at a rate of 5000 rpm/min from GROUND-IDLE to max available Ng without exceeding any operating limits. Reduce to GROUND-IDLE.

c) Press ‘‘Enter’’ on the analyzer to stop recording.

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1) Select ‘‘shutdown Survey’’ from the menu on the analyzer.

2) Press ‘‘Enter’’ on the ACES Analyzer to start recording. Shut down engine from idle.

SHUTDOWN SURVEY

3) End vibration survey after engine reaches 0 rpm and a sync error appears on the ACES Analyzer; then press ‘‘Enter’’ on the ACES Analyzer to stop recording.

1ENg VIBRATION ACCEPTANCE LIMIT

a. From the plots produced above, ensure that 1ENg vibration level does not exceed the following limits:GROUND-IDLE to max Ng ; 0.5 cm/secShutdown from GROUND-IDLE to 5000 rpm Ng; 0.5 cm/sec

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RGB VIBRATION CHECK

1) Set Nf to 33000 +100/-0 rpm.

2) Carry out a slow acceleration (4,000 rpm/min.) from ground idle to maximum attainable Ng, do not exceed any operating limit.

NG SWEEP

3) Carry out a slow deceleration (4,000 rpm/min.) from maximum attainable Ng to ground idle.

4) Record Ng, Nf, torque and vibrations at the highest vibration peak from steps (2) and (3).

NF SWEEP

1) Set Nf to 33000 +100/-0 rpm.

2) Increase power to a torque of 80 ± 3 in. Hg

3) Carry out a slow deceleration (4,000 rpm/min.) from 33000 +100/-0 rpm to 24,500 rpm. Engine torque must be kept at 80 ± 3 in. Hg during deceleration.

4) Carry out a slow acceleration (4,000 rpm/min.) from 24,500 rpm to 33000 +100/-0 rpm. Engine torque must be kept at 80 ± 3 in. Hg during acceleration.

5) Record Ng, Nf, torque and vibrations at the highest vibration peak from steps(3) and (4).

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1) If engine response is sluggish, or acceleration rate is too slow, check P3 and fuel system pneumatic control tubes and connectors for leakage or obstruction, before any fuel control adjustments are made

2) Position power control lever maximum stop on console to limit torque to 86.3 in.Hg.(PT6A-21 engines) or 108.6 in.Hg. (PT6A-27/-28 engines) or maximum obtainable without exceeding engine operating limits. Lock stop on console.

3) Rotate dynamometer controller to give 32000 rpm Nf (97% for PT6A-25, 96% for PT6A-27/28).

4) Record Ng, Nf, Tt1 and δP.

5) Decrease power control lever to flight-idle 23600 ± 100 rpm Ng.

6) Slam accelerate from flight-idle to T.O. timed to 97.5% of take-off Ng. Slam decelerate to ground-idle (19750 ± 500).

NOTE: The time taken to move power control lever in checks (5) through (6) must not exceed 1.0 second, engine should respond smoothly during acceleration and deceleration.

ACCELERATION CHECK

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7) Acceleration time must fall within range specified

NOTE: The time taken to move power control lever in checks (5) through (6) must not exceed 1.0 second, engine should respond smoothly during acceleration and deceleration.

8) If necessary, adjust engine acceleration by rotating FCU acceleration dome one detent at a time, using minimum number to obtain satisfactory acceleration. Rotate dome clockwise to decrease (faster acceleration) and counterclockwise to increase (slower acceleration) acceleration time.

CAUTION: MAXIMUM ADJUSTMENT ON FCU ACCELERATION DOME TO MEET ACCELERATION TIME IS THREE CLICKS CLOCKWISE ORCOUNTERCLOCKWISE.

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9) For example, the inlet screen temp. (TT1) during the day is 80: F, then the acceleration time limits are :low limit = 2.42 + 0.35 = 2.77 secondshi limit = 3.44 + 0.35 = 3.79 seconds

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1) Rotate FCU acceleration dome three detents clockwise to increase fuel flow.

2) Run engine for not less than one minute at maximum stop without exceeding operation limit (Ref. step (2) preceding) to achieve stabilization.

BODIE CHECK

3) Slam decelerate to 32000 Ng (85%), then without dwelling at lower speed, slam accelerate to maximum stop. Repeat to 26000 Ng (70%); again slam to maximum stop. Reduce Ng to GI.

4) If engine is stall and surge free on completion of bodie checks, reset acceleration dome to original position (three detents counterclockwise).

5) If engine stall or surge is experienced during checks, rotate acceleration dome one detent counterclockwise and repeat bodiecheck.

6) If surge is still evident, check compressor bleed valve operation..

7) If bleed valve is functioning correctly, the dome may be reset a further twodetents, a bodie check being implemented after each detent adjustment..

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8) When surge is eliminated, reset dome three detents counter clockwise from surge-free setting.

9) After satisfactory completion of bodie check following adjustment, recheck acceleration time (Ref. steps (5) and (6) ACCELERATION CHECK preceding).

BODIE CHECK continued

10) Following acceptable acceleration and bodie checks, if scribe marks do not align, remove seal and lockwire on FCU acceleration dome. Holding adjusting screw with an Allen wrench, loosen adjuster locknut. Turn dome to re-align scribe marks, then tighten locknut, lockwire and seal. lockwire dome tab.

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TT5 TRIM DETERMINATION

1) Start engine, and advance power control and propeller control levers (propeller testing) or rotate dynamometer controller until engine is operating at observed power of 550 ± 10 SHPCEG (PT6A-21 engines) or 680 ± 10 SHPCEG (PT6A-27/-28 engines) or maximum power obtainable without exceeding engine operating limits and at an NFC equal to 33000 rpm but not to exceed 34200 rpm (NF observed).

2) Run engine for 5 minutes at this power setting to obtain stabilization. Annotate log sheet; Tt5 Trim Determination and record set of readings.Nf, Ng, Pam or Baro, Psn or P1000, Ps3, Δp, SG, Tf, Tsg, Tt1, Tt5, Tt7

3) Determine trim value from readings in step (2), preceding. Process Data with Program PWC83020.

4) With results obtained in step (3) preceding, calculate trim to suppress TT5/TH to a value T5D/TH - 60° ± 10 F° (PT6A-21/-27/-28 engines) or T5D/TH - 65° ± 5 F° (PT6A-28 Piper engines only).Tt5 Trim Determination (example):TT5/TH = 1753°RT5D/TH = 1733°RT5D/TH - 60° = 1733 - 60 = 1673°Rdel T5/TH trim = 1753 – 1673 = 80°

5) Trim value obtained in step (a) preceding is for a 59°F day. To trim engine, this value should be denormalized as follows:

del T5/TH x TH = del T5.

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TT5 TRIM DETERMINATION continued

6) Select appropriate class of trim harness (P/N 3013604 or P/N 3031417) (Ref. Table703).

7) Install selected trim harness (Ref. Final Assembly), and record class in log sheet.

8) Start engine and run at take-off power (Ref. step (1), preceding).

9) After allowing for stabilization of readings, make sure that selected trim reduces Tt5 by the required value. If you are using program PWC83020, check the T5 trim check box and the output screen will state if the trim is good or not. Should it be necessary, install another class of trim and recheck.

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TABLE 703, Trim Harness Classification

3031417 ± 5% @ 70°F Approx. Ohms Approx. Range F° 3013604

Class 10 3.75 to 3.95 -208 to -200 -

Class 11 3.95 to 4.20 -200 to -190 -

Class 12 4.20 to 4.45 -190 to -180 -

Class 13 4.45 to 4.75 -180 to -171 -

Class 14 4.75 to 5.10 -171 to -161 -

Class 15 5.10 to 5.50 -161 to -151 -

Class 16 5.50 to 5.90 -151 to -142 -

Class 17 5.90 to 6.40 -142 to -132 -

Class 18 6.40 to 6.90 -132 to -123 -

Class 19 6.90 to 7.66 -123 to -114 -

Class 20 8 -114 to -104 -

Class 25 9 -104 to - 91 Class 1

Class 30 10.5 - 91 to - 80 Class 2

Class 35 12 - 80 to - 71 Class 3

Class 40 14 - 71 to - 61 Class 5

Class 45 16 - 61 to - 51 Class 7

Class 50 19 - 48 to - 45 Class 10

Class 55 24 - 40 to - 35 Class 20

Class 60 30 - 34 to - 28 Class 30

Class 65 43 - 25 to - 20 Class 40

Class 70 72 - 15 to - 10 Class 50

Class 75 110 - 9 to - 6 Class 60

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FLOW CHART OF TT5 TRIM DETERMINATION

1. Run engine to maximum power obtainable, NFC =

33000 rpm, don't exceed operating limit.

2. Stabilize for 5 minutes.

3. Take fullset reading

START

TSG, SG, LHV, Ng, Nf, Pbaro,

Psn, P3, Tt5, Torq1, delP,

Wf,Tfuel, Tt1, Tt7

Input to and process

with Program Drp

PWC83020

TT5TH AND T5DTHNOTE :

TH = (Tt1+459.688)/518.688

delT5TH = TT5TH - (T5DTH - 60)

delT5 = delT5TH x TH

delT5

LOOKUP TABLE 703

TRIM

CLASS

install trim harness

1. Run engine to TAKEOFF or maximum power

obtainable, NFC = 33000 rpm, don't exceed

operating limit.

2. Make sure that selected trim reduces Tt5 by the

required value.

SELESAI

example :

TH = 1.05,

TT5TH = 1753 R,

T5DTH = 1733 R,

delT5TH = 1753 - (1733 - 60) = 80,

delT5 = 80 x 1.05 = 84,

lookup table 703, p/n : 3031417

trim class = class 30, -91 to -80

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EXAMPLE OF TT5 TRIM DETERMINATION

The data from left column above, taken from fullset @ takeoff. The data will process with DRP program PWC83020.

The output from program are :THETA = (ENGINE INLET TEMP + 459.688)/518.688

= (85.93 + 459.688)/518.688 = 1.05T5D/THETA = 1723.8 deg RCORR.TT5 (TT5/THETA) = 1752.4 deg R

With refer to flow chart, then :(T5D/THETA ) - 60 = 1723.8 – 60 = 1663.8DELTA TT5/ THETA TRIM = CORR.TT5 (TT5/THETA) – (T5D/THETA) – 60

= 1752.4 – 1663.8 = 88.6DELTA TT5 DENORMALIZE = DELTA TT5/ THETA TRIM X THETA

= 88.6 X 1.05 = 93.03 = 93LOOKUP TO TABLE 703 → 93 → CLASS 25 OR CLASS 30

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ACCEPTANCE CHECK (PERFORMANCE)

Before we move deeply to Acceptance Check, better if we have a goodunderstanding on several important parameter which were used fordetermine the result of acceptance check .

The parameter which mentioned above are SHPCEG, NGC, WFC, SFC andTT5C.

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SHPCEG BLOCK DIAGRAM

TT5

(interturbine temp)deg FTT5 DEG R

(tt5 + 459.688)

TT5C or TT5TH

(TT5 DEG R / THETA )

TT1 AVG

(engine inlet temp)deg F

THETA

(tt1 avg + 459.688 / 518.688)

TT5C or TT5TH BLOCK DIAGRAM

TORQ3

(static torq press) psig

TORQ2

(torqmeter press)psig

NF

(power turbine speed)rpm

KONSTAN

PT6A-27 = 5272

PT6A-25 = 5183

PBAR

(ambient press)

standard press

(14.696 psi)

TT1 avg


del P

(torq2 - torq3 x 2.036)

SHP

(del P x NF / KONSTAN)

psia

DELTA

(pbar / standard press)

THETA

(tt1 avg + 459.688) / 518.688

sq root THETA

(theta ̂0.5)

SHPCEG

(SHP / DELTA / sqroot THETA)

27



WFC BLOCK DIAGRAM

SFCC BLOCK DIAGRAM

FTSAMP

(fuel sample temp) deg F

SPGRAV

(fuel spec. gravity) psig

WFGPM

(fuel flow)gpm

PBAR

(ambient press)

standard press

(14.696 psi)

TT1 avg


CORR SPGRAV

(spgrav-1.2875)/(ftsamp+1164)x(tfuel-ftsamf)+spgrav

psia

DELTA


THETA

(tt1 avg + 459.688) / 518.688

sq root THETA

(theta ̂0.5)

WFC

(wfpph / DELTA x sqroot THETA)

TFUEL

(fuel temp)deg F

WFPPH

(wfgpm x 499.68 x corr spgrav)

SHPCEG

(corr shp engine)

WFC

(corr WF)

hp

SFCC

(shpceg / wfc)

pph

28



NGC BLOCK DIAGRAM

TT7C BLOCK DIAGRAM

TT1 avg

(engine inlet temp)deg FTHETA

(tt1 avg + 459.688) / 518.688

sq root THETA

(theta ̂0.5)

NGC

(ng / sqroot THETA)

NG

(gas producer speed)rpm

TT1 avg

(engine inlet temp)deg FTHETA

(tt1 avg + 459.688) / 518.688

TT7AC

(TT7A DEG R / THETA)

TT7 AVG

(engine exhaust nozzle temp)deg F

TT7A DEG R

(tt7 avg + 459.688)

PBAR

(ambient press)

standard press

(14.696 psi)

PS3

(compressor discharge press)psig

psia

DELTA


PS3C

(PS3 / DELTA )

PS3C BLOCK DIAGRAM

29



PROCEDURE

CAUTION : DO NOT EXCEED ENGINE OPERATING LIMITS

1) Run to following powers at Nf/RTH equal to 33000 rpm, but not to exceed 34200 rpm (observed).

2) Record readings for each of the power setting points :

3) PT6A-21 or PT6A -25 engines: :

a) 550 SHP/DELRTH or maximum power obtainable.

a) 495 SHP/DELRTH.

4) PT6A-27/28 engines: :

a) 680 SHP/DELRTH or maximum power obtainable.

a) 620 SHP/DELRTH.

5) From readings obtained in steps (3) or (4) preceding, process data with program PWC83020. Plot the best straight line across the normalized values of Wf, Tt5 and Ng against shp on engine performance graph. (Ref. Fig. 711).

30



PROCEDURE

31



ACCEPTANCE VALUE

1) Enter curve at 550 shp (PT6A-21 engines) or 680 shp (PT6A-27/-28 engines) and record corresponding values for SFC, Tt5 and Ng for take-off power in corrected engine performance block.

2) Check parameters determined in step (1) against required parameters (Ref. Table 704).

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ACCEPTANCE VALUE

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ACCEPTANCE VALUE

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ACCEPTANCE VALUE

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ACCEPTANCE VALUE

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ACCEPTANCE VALUE

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ACCEPTANCE VALUE

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ACCEPTANCE VALUE

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ACCEPTANCE VALUE

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ACCEPTANCE VALUE

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ACCEPTANCE CHECK – performance calculation example

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pt6a engine testing

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