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Aircraft Powerplant Handbook, Airframe and Power Plant Series
Mechanics Handbook
516 pages
U.S. Department of Transportation

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Open: Aircraft Powerplant Handbook, Airframe and Power Plant Series

This advisory circular is printed for persons preparing for a mechanics certificate with a powerplant rating. It is intended to provide basic information on principles, fundamentals, and technical procedures in the areas relating to the power- plant rating. This is designed to serve as a guide for students enrolled in a formal course of instruction, as well as the individual who is studying on his own.

This volume is devoted to an explanation of the units which make up each of the systems that bring fuel, air, and ignition together in an aircraft engine for combustion. It also contains information on engine construction features, lubrication systems, exhaust systems, cooling systems, cylinder removal and replacement, compression checks, and valve adjustments.

Because there are so many different types of aircraft engines in use today, it is reasonable to expect minor differences to exist in like system components. To avoid undue repetition, the practice of using representative systems and units is carried out throughout the advisory circular. Subject-matter treatment throughout the text is from a generalized point of view and its use can be supplemented by reference to manufacturer's manuals and other textbooks if more detail is desired. This advisory circular is not intended to replace, substitute for, or supersede official regulations or manufacturer's instructions which should be consulted for final authority.

Grateful acknowledgement is extended to the manufacturers of engine, propellers, and powerplant accessories for their cooperation in making material available for inclusion in this handbook.

TOC

PREFACE iii
CONTENTS v
CHAPTER 1.— THEORY AND CONSTRUCTION OF AIRCRAFT ENGINES
General 1
Comparison of Aircraft Powerplants 2
Types of Reciprocating Engines 4
Reciprocating Engine Design and Construction 5
Crankshafts 11
Connecting Rods 12
Pistons IS Piston Rings 16
Cylinders 17
Cylinder Numbering 18
Firing Order 19 Valves 20
Valve-Operating Mechanism 21
Bearings 21
Propeller Reduction Gearing 25
Propeller Shafts 26
Reciprocating Engine Operating Principles 26
Operating Cycles 28
Four-Stroke Cycle 28
Reciprocating Engine Power and Efficiencies 30
Efficiencies 36
Turbine Engine Construction 38
Air Entrance 40
Accessory Section 41
Compressor Section 42
Combustion Section 48
Major Subassemblies 61
Turboprop Engines 63
Turboshaft Engines 63
Turbofan Engines 64
Turbine Engine Operating Principles 65 Thrust 66
Gas Turbine Engine Performance 67

CHAPTER 2— INDUCTION AND EXHAUST SYSTEMS
Reciprocating Engine Induction Systems 71
Induction System Icing 73
Internally Driven Superchargers 75
Externally Driven Superchargers 80
Turbosupercharger System for Large Reciprocating Engines 80
Turbochargcr 84
Sea Level Boosted Turbocharger System 86
Turbocompound S\ stems for Reciprocating Engines 89
Turbojet Engine Inlet Duct Systems 90
Turboprop Compressor Inlets 94
Reciprocating Engine Exhaust Systems 95
Reciprocating Engine Exhaust System Maintenance Practices 98
Turbine Engine Exhaust Ducts 101
Turboprop Exhaust S\ stem 102
Thrust Re\ ersei> 103
Engine Air-Inlet Vortex Destroyer 106

CHAPTER 3— ENGINE FUEL AND FUEL METERING SYSTEMS
Fuel System Requirements 109
Basic Fuel S\ stem 110
Fuel Metering Devices for Reciprocating Engines 110
Caiburetion Principles 113
Carburetor Sn stems 115
Carburetor T\ pes 116
Carburetor Icing 116
Float-Type Carburetors 117
Pressure Injection Carburetors 122
Stromberg PS Series Carburetor 134
Direct Fuel-Injection Systems 136
Carburetor Maintenance 142
Fuel System Inspection and Maintenance 146
Water Injection System for Reciprocating Engines 147
Turbine Engine Fuel System — General Requirements 119
Jet Fuel Controls U9 Coordinator 153
Fuel Control .-. .• 153
Speed-Sensor Control 151
Fuel Manifold Drain Valve 151
System Operation 151
Hydromechanical Fuel Control 156
Fuel Control Description 1 56
Fuel Scheduling System 163
Water Injection Re-Set System 167
Jet Fuel Control Maintenance 167
Engine Fuel System Components 169
Fuel Quantit) Indicating Units 171
Water or Coolant Injection 171

CHAPTER 4— ENGINE IGNITION AND ELECTRICAL SYSTEMS
Reciprocating Engine Ignition Systems 1
Battery Ignition System 177
Magneto Ignition System Operating Principles 177
Timing High-Tension System Distributor Fingers 208
Spark Plug Inspection and Maintenance 213
The Engine Analyzer 228
Turbine Engine Ignition Systems 230
Ignition System Inspection and Maintenance 23
Removal, Maintenance, and Installation of Ignition System Components 235
Powerplant Electrical Systems 233
Lacing and Tying Wire Bundles 246
Cutting Wire and Cable 249
Stripping Wire and Cable 250
Emergency Splicing Repairs 253
Connecting Terminal Lugs to Terminal Blocks 254
Bonding and Grounding 255
Connectors 257
Conduit 260
Electrical Equipment Installation 260

CHAPTER 5.-ENGINE STARTING SYSTEMS General 263
Reciprocating Engine Starting Systems 263
Starting System Using Combination Inertia Starter 263
Direct-Cranking Electric Starting System for Large Reciprocating Engines 265
Direct-Cranking Electric Starting System for Small Aircraft 260
Gas Turbine Engine Starters 270
Air Turbine Starters 276
Cartridge/Pneumatic Turbine Engine Starter 279
Fuel/Air Combustion Turbine Starter 283
Auxiliary Ignition Units 190
Spark Plugs 195
Reciprocating Engine Ignition System Maintenance and Inspection 196
Magneto Ignition Timing Devices '^7
Checking the Internal Timing of a Magneto 201

CHAPTER 6.— LUBRICATION AND COOLING SYSTEMS
Principles of Engine Lubrication 285
Requirements and Characteristics of Reciprocating Engine Lubricants. . 285
Reciprocating Engine Lubrication Systems 286
Internal Lubrication of Reciprocating Engines 293
Lubrication System Maintenance Practices 291
Requirements for Turbine Engine Lubricants 30]
Turbine Engine Lubrication Systems 302
Typical Dry Sump Lubrication System 308
Engine Cooling Systems 314
Inspection of Cowling 318
Engine Cylinder Cooling Fin Inspection 319
Turbine Engine Cooling 322

CHAPTER 7— PROPELLERS General 325
Basic Propeller Principles 325
Propeller Operation 327
Types of Propellers 329
Classification of Propellers 331
Propellers Used on Light Aircraft 331
Constant Speed Propellers 331
Feathering 335
Hamilton Standard Hydromatic Propellers 338
Hydraulic Governors 344
Propeller Synchronization 347
Propeller Ice Control Systems 347
Propeller Inspection and Maintenance 349
Propeller Vibration 350
Blade Tracking 350
Checking and Adjusting Propeller Blade Angles 350
Propeller Balancing 352
Servicing Propellers 353
Turboprop Propeller 357
Blade Cuffs 358

CHAPTER 8.— ENGINE REMOVAL AND REPLACEMENT
General 359
Reasons for Removal of Reciprocating Engines 359
Preparation of Reciprocating Engines for Installation 361
QECA Buildup of Radial Engines 361
Inspection and Replacement of Powerplant External Units and Systems 364
Preparing the Engine for Removal 365
Removing the Engine 368
Hoisting and Mounting the Engine for Installation 369
Preparation of Engine for Ground and Flight Testing 372
Propeller Check 373
Checks and Adjustments after Engine Run-up and Operation 374
Removal and Installation of an Opposed-Type Engine 374
Engine Installation 375
Turbojet Powerplant Removal and Installation 375
Installation of Turbojet Engines 377
Rigging. Inspections, and Adjustments 378
Turboprop Powerplant Removal and Installation 380
Helicopter Engine Removal and Installation 381
Rigging and Adjustment of Helicopter QECA 382
Engine Mounts 382
Preservation and Storage of Engines 386
Corrosion Preventive Treatment 387
Engine Shipping Containers 388
Inspection of Stored Engines 390
Preservation and De-preservation of Gas Turbine Engines 390

CHAPTER 9.— ENGINE FIRE PROTECTION SYSTEMS
General 391
Reciprocating Engine Fire Protection Systems 391
Fire Zones 394
Fire Extinguishing Agents 394
Turbine Engine Fire Protection Systems 397
Typical Multi-Engine Fire Protection System 399
Fire Detection System Maintenance Practices 403
Fire Extinguisher System Maintenance Practices 406
Turbojet Aircraft Fire Protection System | Saberliner) 407

CHAPTER 10.— ENGINE MAINTENANCE AND OPERATION
Reciprocating Engine Overhaul 411
General Overhaul Procedures 411
Cylinder Assembly Reconditioning 415
Crankshaft Inspection 428
Connecting Rods 428
Block Testing of Reciprocating Engines 429
Reciprocating Engine Operation 436
Basic Engine Operating Principals 442
Factors Affecting Engine Operation 446
Engine Troubleshooting 453
Cylinder Maintenance 457
Cylinder Compression Tests 459
Cylinder Removal 462
Cylinder Installation 463
Valve and Valve Mechanism 465
Cold Cylinder Check 470
Turbine Engine Maintenance 472
Combustion Section 476
Inspection and Repair of Turbine Disc ^79
Commercial Ratings 483
Engine Instrumentation 483
Turbojet Engine Operation 486
Ground Operation 488
Engine Shutdown 489
Troubleshooting Turbojet Engines 490
Turboprop Operation 490
Troubleshooting Procedures for Turboprop Engines 492
Jet Calibration Test Unit 493
Troubleshooting Aircraft Tachometer System 497
Spectrometric Oil Analysis Program 498