J « FM 55-63 7 FIELD MANUAL s ■f/T? 2/ ENTAL AIRFRAME MAINT RETURN TO ARMY LIBRARY ROOM 1 A 518 PENTAGON HEADQUARTERS DEP A R TMEN T 0 F T HE A RMY IANUARY 1974 *FM 55-63 FIELD MANUAL HEADQUARTERS DEPARTMENT OF THE ARMY NO. 65-63 WASHINGTON, D.C., 31 January 1974 FUNDAMENTALS OF AIRFRAME MAINTENANCE Paragraph Paffe CHAPTER 1. INTRODUCTION - 1,2 1 2. AIRCRAFT STRUCTURES Section I. General - 8,4 2 II. Principal Structural Units - 5-8 2 III. Aerodynamic Forces - 9-14 13 CHAPTER 3. AIRCRAFT STRUCTURAL METALS Section I. Properties and Characteristics 16,16 16 II. Metalworking Processes 17-28 18 CHAPTER 4. SHEET METAL TOOLS AND SHOP EQUIPMENT Section I. General 29, 80 57 II. Basic Hand Tools - 31-36 57 III. Special Tools and Devices — - 37,38 83 IV. Sheet Metal Shop Equipment 39-43 86 CHAPTER 6. ENGINEERING DRAWING AND BLUEPRINT READING Section I. Introduction 44,45 102 II. Type of Lines and Scale and Size . - 46,47 103 III. Dimensioning 48-60 108 IV. Types of Drawings and Views 61,62 111 V. Blueprints and Use of Microfilm 63,64 118 CHAPTER 6. FORMING PROCESS Section I. General - 66-68 121 II. Forming Operations 69-73 123 III. Forming Terms - 74-80 125 IV. Straight Line Bends or Folds 81-84 126 V. Methods of Evolving Patterns or Templates . - 86-87 133 VI. Hand-Forming of Aluminum 88-94 139 CHAPTER 7. RIVETS, SPECIAL PURPOSE BOLTS Section I. General - 95-97 148 II. Solid Shank Rivets 98-104 148 III. Special Rivets — 105-108 165 IV. Special Purpose Bolts 109-110 174 CHAPTER 8. FASTENERS Section I. General Ill, 112 187 II. Aircraft Bolts 118-116 187 III. Aircraft Nuts 117,118 197 IV. Aircraft Washers 119,120 206 V. Installation of Bolts and Nuts 121,122 210 VI. Aircraft Screws 123-125 211 VII. Turnlock Fasteners - - 126^1.28 222 CHAPTER 9. AIRFRAME REPAIR Section I. Basic Principles of Repair 129-132 230 II. General Structural Repair - 133-141 232 III. Structural Sealing 142-146 249 IV. Repair of Fuel Tanks 147-152 251 V. Sandwich Construction 153-156 253 VI. Repair of Sandwich Construction 157-162 256 CHAPTER 10. FLIGHT CONTROL SYSTEMS Section I. Flight Control Surfaces and Systems of Airplanes 163-165 261 lit manual tupertedet TM 55-408, B Jim* 1965, including all changet. Paragraph Page II. Flight Control Surfaces and Systems of Helicopters 166-168 269 III. Cable Linkage __ 169-173 271 IV. Push-Pull Linkage 174-176 275 V. Rigging 177-180 276 CHAPTER 11. REBALANCING OF MOVABLE € SURFACES Section I. General - 181,182 281 II. General Considerations in Balancing Surfaces 183-185 281 III. General Balancing Procedures J.86-187 283 CHAPTER 12. AIRFRAME WELDING Section I. Gas Welding, Brazing, and Soldering 188-204 288 II. Electric Arc Welding 205-215 316 III. Inert-Gas Shielded Arc Welding 216,217 842 CHAPTER 13. AIRCRAFT PLASTICS Section I. General 218,219 363 II. Transparent Thermoplastics 220-222 363 III. Transparent Acrylic Thermoplastics 223-230 364 IV. Transparent Cellulose Acetate Base Thermoplastics 1231, 232 381 V. Thermosetting Plastics (Reinforced Fiberglass) 233-238 381 APPENDIX A - 389 INDEX 390 € € ¡i INDEX Paragraph Page Paragraph Pase Acrylic plastic panels, transparent, Airframe parts (airplane), princi- installation 230 879 pal 6 2 Bolt and rivet mountings 230 379 Empennage 6d 8 General installation information . 230 379 Fuselage 6a 2 Synthetic fiber edge attachments - 230 379 Nacelle - 66 5 Acrylic thermoplastics, transparent, Wings 6c 5 cementing 225 369 Airframe parts (helicopter), prin- ' Assembling 225e 371 cipal 7 11 Pitting 2256 371 Cabin section 7a 11 Masking - 225c 371 Main rotor blades 7c 11 Methods 225a 369 Stabilizer - 76 11 Soaking — 225d 371 Tail cone section 7a 11 Acrylic thermoplastics, transparent, Tail rotor blades 7c 11 curing 226 372 Airframe patching procedures 140d 239 Acrylic thermoplastics, transparent, Airframe repair, basic principles: fabricating 224 367 General - 129 230 Drilling 224/ 369 Keeping weight to a minimum .. 132 232 Lay out 2246 367 Maintaining original contour 131 232 Routing - - 224d 368 Maintaining original strength -- 130 230 Sawing 224c 368 Airloc fastener 126d 223 Scribing and edge sanding 224e 369 Alloying 17 18 Acrylic thermoplastics, transparent, Aluminum and aluminum alloys 22 34 finishing 228 376 Description 22a 34 Annealing 228e 377 Identification 226 34 Ashing 2286 377 Working practices 22c 36 Buffing 228c 377 Aluminum, hand forming: Polishing 228d 377 Curving formed or extruded Sanding 228a 376 angles - 90 140 Acrylic thermoplastics, transparent, Forming by bumping 93 144 forming 223 364 Forming curved flange parts 92 141 Forms 223c 365 Forming flanged angles 91 141 Heating for forming _ 2236 364 Joggling 94 146 Methods - 223d 365 Straight line bends 89 140 Acrylic thermoplastics, transparent, Angle of attack 11 15 heat treatment 226 372 Annealing transparent acrylic thermo- Acrylic thermoplastics, transparent, plastics 228e 377 maintenance 229 377 Anvils 37a 83 Cleaning 2296 378 Ashing transparent acrylic thermo- Hot climate precautions 229e 378 plastics 2286 377 Polishing 229c 378 Waxing 229d 378 Balancing, control surface 181 281 Acrylic thermoplastics, transparent, Balancing movable surfaces, prin- repair 227 373 ciples 186 283 Emergency repairs 227a 373 Bandsaw, contour 40d 90 Permanent repairs 2276 374 Bar folder 43a 96 Adhesives, sandwich construction 156 255 Barcol tester 28e 54 Ailerons 163c 261 Bellcranks : Air density 13 15 Inspection 176a 276 Aircraft structures : Installation 176c 276 Early 3 2 Repair 1766 276 Present day 4 2 Benchplates 376 83 Airfoil 10d(l) 14 Bend allowance, metal 81 126 Shape 14 15 Bending metal 73 124 Speed 12 15 Bernoulli's principle 10d(2) 14 Hi Paragraph Page Paragraph Blueprints 63 118 Clamp 172a(3) 272 Bill of material and specifica- Clevis __ 172a(4) 272 tions 636 119 Clip 172a(5) 272 Change or revision block 636 120 Fork I72a(7) 272 Finish marks 63e 119 Shackle. 172a(8) 272 Notes 63i 120 Socket 172a(9) 272 Station numbers 63d 119 Stop 172a(10) 272 Title block 63a 118 Thimble 172a(ll) 273 Tolerances 63/ 119 Tumbuckle 172a (12) 273 Usage block 63p 120 Cable inspection 173a 273 Zone numbers 63c 119 Broken wires _ 173a(l) 273 Bolt and bolthole sizes 121 210 Corrosion 173a(2) 273 Bolts, standard, identification 114 187 Wear... 173a(3) 273 Bolthead markings 114 187 Cable tension, adjusting 179 277 Part number designations 114 187 Calipers 31i 59 Bolts, types of : Calipers, micrometer 31/ 60 Clevis 116 188 Camloc fastener 126c 222 Close tolerance 116 188 Castellated nuts 118a(l) 198 Drilled head _ 116 188 Castle shear nuts 118a(2) 198 Hexagon head 116 188 Cellulose acetate base thermoplastics, Internal wrenching 116 188 transparent : Bolts versus screws 112 187 General 231 381 Bonded magnesium panels, repair _. _ 159 257 Working practices 232 381 Bonded stiffeners 158 257 Cellulose plastics 219d 363 Box and pan brake 43c 98 Cementing transparent acrylic therm- Brake line, locating 83 128 oplastics. (See Acrylic thermoplas- Brakes, speed 1656 267 tics, transparent, cementing.) Brinell tester 286 51 Chisels 341 78 Bucking bars 102a(l)(c) 156 Cleco fasteners 32a (1) 68 Buffing transparent acrylic thermo- Clevis bolts H6e 188 plastics 228c 377 Close tolerance bolts 1166 188 Bulkhead repair - - „ 141e 245 Coding: Bumping metal _.. _ _ 69 123 Nuts 1176 197 Buring tools 34m 79 Screws 124 212 Coin tapping technique 161 260 C-clamp 32a (2) 68 Cold working of metal 20 22 Cable accessories : Collective pitch control 167a 269 Actuator 1726(1) 273 Combination set 31/ 58 Bellcrank 1726 (2) 273 Compasses, pencil 31A 58 Cable drum 1726(3) 273 Connectors, plumbing. (See Plumbing Fairlead 1726(4) 273 connectors.) Pulley 1726(5) 273 Control surface balancing ... 181 281 Quadrant 1726(6) 273 Control surface travel, limiting _ _... 180 278 Sheave 1726 (7) 273 Controls, neutralizing 178 276 Cable construction 170 271 Copper and copper alloys: Cable fabrication 173 273 Description ... 27a 50 Cutting 1736(1) 273 Identification 276 50 Swaging 1736(2) 274 Working practices 27c 50 Cable fabrication hardware 172 272 Core materials for sandwich construc- Cable fittings. (See specific item.) tion _ 154 253 Cable accessories. (See specific item.) Cornice brake 436 97 Cable fabrication terms : Corrosion : Free end 171/ 272 Control 137 233 Serving 171¿ 272 Inspection 137 237 Size 171o 271 Removal 137 237 Splicing I7ic 272 Treatment 137 237 Standing length 171/ 272 Corrosion, common types 1376 235 Swaging 1716 271 Concentration cell corrosion 1376(6) 236 Tucking nig 272 Exfoliation corrosion 1376(4) 235 Unlaying 17ie 272 Fatigue corrosion .. 1376(8) 237 Cable fittings : Galvanic corrision 1376(5) 235 Ball type 172a(l) 272 Intergranular corrosion ...... .. 1376(3) 235 Bushing 172a(2) 272 Pitting corrosion 1376(2) 235 Cable eye I72a(6) 272 Stress corrosion cracking 1376(7) 237 tv Paragraph Page Paragraph Paw Uniform etch corrosion 1376(1) 235 Dzus fastener (stud, grommet, and Counterbores 34J 76 receptacle) 1266 222 Countersinking rivets 1026(1) (6) 160 Dzus fastener (stud, grommet, and Countersinks - - - 34; 76 spring) 126a 222 102a(l)(e) 157 Electrical screws 125d Countersunk-head rivets, removal — 1046 165 214 Elevators 163a Countersunk washers - 120c 207 261 Engine self-locking nuts 1186(3) Crimping metal - 201 Epoxy resins 2606 Curing transparent acrylic thermo- 70 124 plastics - 226 372 Fabricating transparent acrylic Cutters, rivet 102a(l)(6) 155 thermoplastics. (See Acrylic therm- Cyclic pitch control . 166 269 oplastics, transparent, fabricating.) Fabrication of cable. (See cable fabri- Damage, structural, classification. cation.) (See Structural damage, classifi- Fabrication of rebalance weights .. 187c cation.) - - 287 Facing materials for sandwich con- Dies 34A 75 struction 154 Dimensioning 48 108 253 Fasteners, turnlock.