FUEL MANAGEME NT

1. FUEL MANAGEMENT RECOMMENDATIONS FOR BEST ECONOMY & LONG LIFE JIM MOSS

2. TOPICS • OBJECTIVES • DEFINITIONS • GENERAL RULES OF OPERATION • INJECTION VS. CARBURETION • LOW POWER / LOW RPM • INSTRUMENT CALIBRATION • LEAN OF PEAK OPERATION

3. OBJECTIVES • REDUCE FUEL CONSUMPTION • THRU PROPER LEANING • GREATER RANGE • REDUCE OPERATING COSTS • REDUCED FUEL CONSUMPTION • LESS MAINTENANCE • REDUCED SPARK PLUG FOULING • EXTEND ENGINE LIFE • MAINTAIN PROPER TEMPS • LESS CYLINDER COMPONENT WEAR

4. DEFINITIONS • PEAK EGT • PEAK EXHAUST GAS TEMP • CHEMICALLY CORRECT AIR-FUEL MIXTURE • 100% UTILIZATION OF ALL THE FUEL AND ALL THE AIR • ROP • RICH OF PEAK EGT • EXCESS FUEL TO AIR • COOLING OCCURS • LOP • LEAN OF PEAK EGT • EXCESS AIR TO FUEL • COOLING OCCURS • DA • DENSITY ALTITUDE • ALTITUDE CORRECTED FOR NON- STANDARD TEMPERATURE , PRESSURE AND DEW POINT • MP • MANIFOLD PRESSURE • INDICATION OF POWER

5. GENERAL RULES FOR NORMALLY ASPIRATED ENGINES • ALL LEANING RECOMMENDATIONS ARE BASED ON CALIBRATED INTRUMENTATION • OBSERVE RED-LINE TEMP LIMITS • TAKE OFF, CLIMB, HIGH PERFORMANCE CRUISE • CHT PER OPERATORS MANUAL • OIL TEMP OPERATORS MANUAL • ADJUST MIXTURE SLOWLY • RICH OR LEAN • AVOID SHOCK COOLING • DO NOT EXCEED 50 F PER MINUTE • ALWAYS RETURN MIXTURE SLOWLY TO FULL RICH • BEFORE INCREASING POWER SETTING

6. GENERAL RULESFOR NORMALLY ASPIRATED ENGINES • FULL RICH MIXTURE • TAKE OFF • CLIMB • HIGH PERFORMANCE CRUISE • EXCEPTIONS : • DENSITY ALTITUDE TAKE OFF • 5000’ DA • 3000’ DA FOR SOME CESSNA MODELS • BENDIX PS PRESSURE CARBS • CLIMB AT HIGHER ALTITUDE • MAXIMUM POWER MIXTURE • PERFORMANCE CRUISE POWER • PILOT OPERATING HANDBOOK • BEST ECONOMY MIXTURE • ECONOMY CRUISE POWER • PILOT OPERATING HANDBOOK

7. GENERAL RULESFOR NORMALLY ASPIRATED ENGINES • DURING DESCENT OR REDUCED POWER OPERATIONS • LEAVE MIXTURE SETTING AT CRUISE POSITION • MANUAL LEANING • LANDING • FULL RICH POSITION • LEANED SETTING FOR DA

8. METHODSFORSETTING MIXTURE • MAXIMUM POWER • SET CRUISE POWER PER POH • LEAN MIXTURE FROM FULL RICH • ASI PEAK OR TACH RPM PEAK (FIXED PITCH) • ASI PEAK (CONSTANT SPEED) • 100 F RICH OF PEAK EGT • BEST ECONOMY • SET CRUISE POWER PER POH • LEAN MIXTURE FROM FULL RICH • UNTIL ENGINE RUNS ROUGH, OR • UNTIL ASI DECREASE IS NOTED • ENRICHEN UNTIL ENGINE IS SMOOTH • ENRICHEN UNTIL AIRSPEED IS REGAINED • OPERATE AT PEAK EGT • SOME ENGINE POWER AND AIRSPEED MUST BE SACRIFICED TO GAIN ECONOMY

9. GROUNDOPERATIONS • PROPER ADJUSTMENT OF IDLE SPEED FUEL MIXTURE • @ 600-650 RPM • STARTUP & INITIAL WARMUP • AVOID PROLONGED CLOSED THROTTLE ENGINE IDLE SPEED • 1000-1200 RPM • RETARDS FORMATION OF LEAD SALT DEPOSITS • AVOID RAPID ENGINE COOL DOWN • PRIOR TO SHUTDOWN • 1000-1200 RPM UNTIL TEMPS STABILIZE • INCREASE SPEED TO 1800 RPM FOR 15-30 SEC • REDUCE TO 1000 RPM • SHUT DOWN IMMEDIATELY

11. ECONOMYCRUISE POWER • 55 TO 75% OF MAXIMUM POWER • LEAN TO BEST ECONOMY • PEAK EGT • MAY BE LEANED AT ANY ALTITUDE • NOT TO EXCEED 75% POWER • NOT FOR TAKE OFF & CLIMB • DAMAGE WILL NOT OCCUR FROM LEANING AT ECONOMY CRUISE POWER SETTINGS • IF CHT REACHES PEAK BEFORE EGT, USE CHT TO DICTATE LIMIT OF LEANING

13. DIRECT DRIVEFIXED PITCHNORMALLY ASPIRATED • HIGHER ALTITUDE REQUIRES HIGHER RPM TO MAINTAIN POWER • NO MANIFOLD PRESSURE GUAGE • LEAN FOR ANY ALTITUDE • 75% POWER OR LESS

15. MAXIMUMSERVICE LIFE • MAINTAIN THE FOLLOWING RECOMMENDED LIMITS FOR CONTINUOUS CRUISE OPERATION • ENGINE POWER SETTING • 65% OF RATED POWER, OR LESS • CYLINDER HEAD TEMPERATURE • 400 F OR BELOW • OIL TEMPERATURE • 165 F TO 220 F

16. CARBURETOR VSFUEL INJECTION • CARBURETOR • $ • SIMPLE • UNBALANCED DISTRIBUTION • OK ECONOMY • CARB ICING • ADVERSELY AFFECTED BY COLD WX • UPRIGHT • LARGE LINES • ??? • FUEL INJECTION • $$$ • COMPLEX • PRECISE DISTRIBUTION • IMPROVED ECONOMY • NO ICING • AFFECTED BY COLD WEATHER • AEROBATIC • SMALL LINES • FUEL FLOW DATA

17. LOW POWER/LOW RPMCONSIDERATIONS • PRO • LOWER RPM = LESS FRICTION • LONGER LIFE • FUEL SAVINGS • LOWER VIBRATION • LESS NOISE • CON • LOWER POWER = REDUCED PERFORMANCE • AVOID HIGH MP/LOW RPM • DETONATION • COLD WEATHER • TEMPS < NORMAL • EXCESSIVE OIL USAGE • NOT FOR BREAK-IN

21. INSTRUMENT CALIBRATION • TACHOMETER • PHOTO TACH VERIFICATION • MANIFOLD PRESSURE • REMOTE MANUAL GUAGE • OIL TEMP GUAGE • REMOTE MANUAL GUAGE • BOILING WATER • CYLINDER HEAD TEMP • BOILING WATER • RESISTANCE, MILLIVOLT OUTPUT • EXHAUST GAS TEMP • OEM TEST TOOL • BOILING WATER • RESISTANCE, MILLIVOLT OUTPUT TEST

22. LEAN OF PEAKOPERATION • THOUGHT TO BE A CONSPIRACY • MFG SELLS MORE ENGINE PARTS • OEM PADS PERFORMANCE DATA • NACA RESEARCH FROM 1943 • TOP SECRET PROJECT • EXTEND RANGE OF MILITARY A/C • COOLER & CLEANER • 19,000 SETS OF GAMI INJECTORS • SEVERAL HUNDRED THOUSAND HOURS OF OPERATION • OEMS NOW REQUIRE LOP OPERATION

23. LEAN OF PEAKOPERATION • REDUCE FUEL CONSUMPTION • UP TO 20% • REDUCE OPERATING COSTS • REDUCED MAINTENANCE • EXTEND ENGINE LIFE • LESS WEAR • 5% AIRSPEED LOSS

24. LEAN OF PEAKOPERATION • PROBLEM IS NOT RUNNING LEAN • PROBLEM IS RUNNING TOO RICH WITHOUT KNOWING IT • UNEVEN FUEL DISTRIBUTION • OVERFUELING • SOME CYLINDERS ARE MUCH HOTTER THAN OTHERS • RUNNING ROP VS LOP • MORE RESIDUE • WARPED VALVES • WORN CYLINDERS

25. LEAN OF PEAKOPERATION • KEY TO HEALTHY CYLINDERS IS KEEPING THEM COOL • RICH MIXTURE • POUR UNBURNED FUEL THRU • LEAN MIXTURE • RESTRICT FUEL AND REDUCE HEAT • KEEP CHT < 380 F • ENRICHEN MIXTURE IN CLIMB • REDUCE CLIMB ANGLE • DECREASE THE POWER • RUN LOP IN CRUISE

26. LEAN OF PEAKOPERATION • PROPER ENGINE MONITORS REQUIRED • INDIVIDUAL EGT & CHT • GRAPHIC MONITORS HELP • BALANCED FUEL INJECTORS REQUIRED • CANNOT BE USED WITH CARBURETED ENGINES • CANNOT BE USED WITH SINGLE POINT EGT

27. LEAN OF PEAKOPERATION • AIR TAXI OPERATOR RECOMMENDATION • RUN 25-50 F LOP @ 65% POWER • CALM WINDS / TAILWINDS • GREATER RANGE AND ECONOMY • RUN 150 F ROP @ 75% POWER • HEADWINDS • TOP SPEED • PROVIDES A RELIABLE GROUND SPEED

28. REFERENCES • LYCOMING FLYER KEY REPRINTS • AVAILABLE HERE AT AIRVENTURE • AVAILABLE ON LINE • SO WRONG FOR SO LONG BY DAVE HIRSCHMAN • AOPA FRUGAL FLYER • JULY 2009

29. QUESTIONS? Northside.av@gmail.com