MMOPA 2013 Piston Engine Seminar

Transcription

1 MMOPA 2013 Piston Engine Seminar By Chad Menne / Malibu Aerospace Teledyne Continental Motors Gold Motor Textron Lycoming Grey Motor

2 Who am I and why are we here? Chad Menne Owner - Malibu Aerospace Maintain over 100 PA46s/year Over 9,000 hours of PA46 time Corporate flight experience Aircraft management Flight test experience Engineering Research & Development FAA Certification Tests Maintenance / Production Flight Tests

3 Today s Topics Both Lycoming & Continental Engines How do we operate these engines? Why do we operate them that way? What are we missing? What is my mechanic missing? What are common problems?

4 Engine Reliability 98 out of 1385 total accidents were due to powerplant failures (7%), representing 21.4Million flight hours (Nall report 2007). That is one ACCIDENT every 218,367 flight hours caused by engine failures, (turbine & piston), vs one accident every 15,451 hours for ALL causes. You're 14 times more likely to have an accident caused by something other than an engine failure. 11 of them resulted in FATALITIES (0.8%), which equals ONE fatal accident every 1,950,000 flight hours due to engine failure. The TOTAL FATAL accident rate is 1 per 84,920 flight hours for ALL types of accidents in ALL types of planes. You're 23 times more likely to have a FATAL accident caused by something other than an engine failure.

5 Accidents (21,400,000 Hrs) , Total Accidents Engine Accidents Total Fatal Engine Fatal

6 Engine Reliability The piston PA46 fleet averages about 150,000 hours/year That means we should see one accident every 1.5 years and one fatal accident every 13 years due to engine failure (piston & turbine) Some sources claim a piston engine fails every 3,200 flight hours. Pratt & Whitney claims a PT6 failure every 333,000 flight hours by comparison. If the data is correct,(it's difficult to find concrete data), the we should see approximately 47 piston engine failures per year in the PA46 fleet. Either we are maintaining these engines much better than normal, we aren't hearing about the failures, or it may be that a precautionary landing due to an engine problem,(such as rough running), may be counted as an engine failure.

7 Common Problems Both Malibu & Mirage Exhaust! Turbo transitions, slip joints, gaskets, clamps Magnetos Cam wear, moisture/corrosion, points, dist. block Turbochargers Don t expect them to go to TBO Cam & lifter corrosion and wear Excess moisture, fuel dilution, shearing & thermal breakdown of the oil Spark plug resistor failures Measure resistance, it must be under 5,000 Ohms

8 Magneto Pressure Leak

9 Spark Plugs Massive Plug Fine Wire Plug (broken)

10 Spark Plugs Broken Insulator Rusty Plug Core

11 Malibu specific problems Exhaust valves Most common cause from high power & high CHT & exhaust temps Starter drive adapters Lightweight Iskra starters can cause premature wear Air conditioner driveshaft seals can leak Cylinder & ring wear First to be blamed & rarely the cause Bearing end play Check for proper end play during pre-flight and DO NOT fly without end play! Borescope for detailed inspection before condemning a cylinder Be sure to use TCM master orifice tool for daily calibration during a compression check

12 Mirage specific problems Exhaust valve guide wear (high oil consumption and rough running) Broken oil control or compression rings Poor break-in results (high oil consumption) Lycoming does not allow mineral oil Cracked oil sump at turbo support studs Cracked internal oil baffle Be sure to check suction screen for rivets Fuel servo problems Unable to get proper ground mixture or full power fuel flow Can cause surging in cruise Fuel line AD every 100 hours (cracking due to improper securing of lines)

13 Ring Problems Broken Piston Rings Broken Oil Control Rings

14 Ring Problems Overheated Piston Ring Low Tension Blow-by

15 Heat Problems Burned Oil On Pistons Signs of Heat

16 Valve Problems Lycoming TCM Worn Exhaust Valve Worn Valve & Guide

17 Valve Problems Burned Exhaust Valve Burned Valve Seat

18 Believe it, or not! Lifter Main bearing

19 Crankcase bearing journal

20 Crankshaft Bearing Wear

21 Oil Sample - Good

22 Oil Sample - Bad

23 Most Common Sources of Wear Metal Elements in Oil Iron Cylinders, rotating shafts, valve train and any steel part sharing the oil. Copper Brass or bronze parts, bushings, bearings, oil coolers, sacrificial coatings. Nickel Valve guides, trace element in steel, some cylinder types. Chromium Rings, cylinders, a trace element in steel. Silver Sacrificial coatings, a trace element in some types of bearings, bearing cage plating Magnesium Engine casings, additives Aluminum Pistons, piston pin plugs, bearing overlay, casings. Lead Primarily leaded gas blow-by, traces from bearings Silicon Abrasive dirt from intake air, silicone sealers and gaskets, sample contamination. Tin Bearings, bronze parts (with copper), anti-wear coatings. Molybdenum Traces of anti-wear coatings, some cylinder types, and bearings.

24 Exhaust Woes Leaky Gasket Exhaust Gasket

25 Mirage Turbo Transition Heavy, Cast Inconel Erosion & Blistering

26 Malibu Turbo Transition.065 Stainless Steel Check at EVERY Oil Change!

27 Tailpipe Trouble Corrosion has its way Heat Muff - Uncovered

28 V-Band Clamps

29 Exhaust Clamps Malibu & Old-Style Mirage Clamps Crack from over-tightening

30 Exhaust Clamp Engagement The right way The WRONG way

31 Sump Cracks (Turbo Mounts)

32 Sump Repair

33 Oil Sump Baffle

34 Oil Sump Baffle Cracked Oil Baffle Crack at screw attachment hole

35 Turbochargers

36 Common Turbo Problems Compressor damage Bearing failure Seal failure Scavenge pump failure Scavenge hose failure Wastegate failure or sticking Broken or missing mount hardware

37 Turbochargers Bearings Compressor Damage

38 Turbo Trouble Carbon Buildup Flange & Clamp Leakage

39 Engine Cooling

40 Alternate Air Box Linkage

41 Wastegate Actuator Check linkage for wear Check spring for wear against tab Check for oil in drain

42 Broken Rings Check suction screen for parts during oil changes

43 Missing Baffle Hardware Watch for missing bolt in RH Fwd baffle

44 Common Baffle Cracks

45 Intercooler "tool shelves" This is what happens when a tool or part is left on top of the intercooler in flight

46 Broken Filter Drain Tube

47 Things that you can do for your engine Vent oil cap after shutdown (minimize corrosion) Watch EGTs and trend data (ignition and fuel injection anomalies) In-flight mag checks (look for hot or cold EGTs) Oil samples (watch for iron, nickel, almuminum) Watch for peak TIT drift (up or down) Drift up is usually ignition or low compression Drift down is usually a probe going bad

48 The best pilots can juggle The best way to prolong your engine s life and improve safety is to know how to balance parameters Trade one temp for another Engine limits are not intended to provide longest life, but are instead proven to be acceptable for short durations Add fuel only as necessary to achieve a good balance during climb Less fuel means more power! (power means heat)

49 Which is worse??? A. 360 CHT 1650 TIT B. 400 CHT 1580 TIT

50 Which is worse??? A. 360 CHT 1650 TIT The TIT is an exhaust gas temp, the CHT affects the engine s ability to dissipate heat A cooler CHT can transfer more heat away from a valve B. 400 CHT 1580 TIT Less differential from valve to seat and guides removes less heat from valve Localized oil temps will be hotter at valve guides & pistons

51 6% speed loss for 21% fuel savings LOP vs ECON cruise 11% speed loss for 35% fuel savings LOP vs NORM cruise Settings to think about 1kt loss from 50 RPM less and leaned.6 GPH less for same CHT 2kt loss from 140 RPM less and leaned 1.9 GPH less with 10 degree cooler CHT 1kt loss from 110 RPM less and leaned 1.6 GPH less with 8 degree cooler CHT 1kt loss from 90 RPM less and leaned 1.2 GPH less with 2 degree cooler CHT Mirage with fresh TOH, ISA+10 conditions 2kt loss from.8" Hg less and leaned 1 GPH less with 4 degree cooler CHT

52 Operations How hot is too hot??? CHT or EGT/TIT, not both (valve wear) High TIT means more exhaust wear Lean of Peak, no free lunch Lose speed (less power at same power setting) Wear exhaust (higher EGTs, more oxidation) Not as smooth (slight roughness or surging) Cooler CHTs (helps offset the higher EGTs and cool valves)

53 LOP Cost Comparison Continental 20% fuel savings ($28,000 over 2000 hours) 1500 hrs x 21GPH x $4.50/gal - 20% 2% speed loss ($9,000 additional aircraft cost over 2000 hours) 1500 hrs x 200kts - 2% / 196kts x $300/hr Increased exhaust wear costs ($3000 over 2000 hours) Lycoming 25% fuel savings ($35,000 over 2000 hours) 1500 hrs x 21GPH x $4.50/gal -25% 10% speed loss ($50,000 additional cost over 2000 hours) 1500 hrs x 200kts - 10% / 180kts x $300/hr Increased exhaust wear costs ($10,000 over 2000 hours)

54 Ignition timing and combustion speed How to change your ignition timing??? Engine speed Higher RPM = less advance (less time to burn) 2500 RPM = 1 Revolution every.024 seconds Lower RPM = more advance (more time to burn) 2300 RPM = 1 Revolution every.026 seconds or 9% more time Mixture ratio ROP Leaner mixture = more advance (burns faster sharper power pulse) Richer mixture = less advance (burns slower softer power pulse) Mixture ratio LOP Richer mixture = more advance (burns faster sharper power pulse) Leaner mixture = less advance (burns slower softer power pulse)

55 Affects of RPM on Combustion timing Lower RPM (Approx. 4% more time per 100 RPM) Intake Compression Combustion Exhaust Earlier Peak Pressure, More Time to Burn, More Cooling Time per Cycle, Less HP, Cooler EGT, Cooler CHT, Higher Turbo Speeds Higher RPM TDC TDC Peak Pressure Peak Pressure Intake Compression Combustion Exhaust Later Peak Pressure, Less Time to Burn, Less Cooling Time per Cycle, More HP, Hotter EGT, Hotter CHT, Lower Turbo Speeds

56 Affects of mixture on combustion timing ROP Combustion TDC Peak Pressure Intake Compression Combustion Exhaust Faster Combustion, Sharper Pulse, Cooler EGT, Hotter CHT LOP Combustion TDC Peak Pressure Intake Compression Combustion Exhaust Slower Combustion, Lower Pressure, Hotter EGT, Cooler CHT

57 Leaning Techniques No wonder you re confused! Rich of peak, lean to peak, lean of peak TIT peak method, a.k.a. the factory method Fuel flow method JPI lean find Lean L method JPI lean find Lean R method The big pull

58 What s My Horsepower??? Continental LOP, FF x 15 = HP ROP, FF x = HP (Can vary a lot) Lycoming LOP, FF x 14 = HP ROP, FF x 12 = HP (Can vary a lot)

59 Thank you! Questions Comments me, Fly Safe!