Major Structural Components
- Wings
- Fuselage
- Powerplant
- Empennage (Tail Section)
- Undercarriage (Landing Gear)
WINGS
- Wing Position
- Low Wing
- Mid Wing
- High Wing
- Wing Shape
- Rectangular
- Tapered
- Swept (Slight, Moderate, Great, and Forward Sweep Wing)
- Delta (Simple and Complex Delta Wing)
- Wing Number
- Monoplane
- Biplane / Multiple Wings
- Triplane / Multiple Wings
- Others..
- Canard
- Winglet
- Semi-Cantilever (braces)
FUSELAGE
- Nose and Empennage
Parts
- Longerons
- Struts
- Stingers
- Bulkhead
Types
- Monocoque (Single Shell)
- Semimonocoque
POWERPLANT
- Engine Position
- On the wings
- On the wing pylons
- Close to the Fuselage
- Rear Mounted
- Engine Number
- Single Engine
- Twin Engine
- Triple Engine
- Four (Multiple) Engine
- Kind of Engine
- Piston (Propeller)
- Turboprop (Propeller Turbine)
- Jet Engine
- Turbofan
Types of Powerplant
- Tractor (front)
- Pusher (back)
- Variable Direction
EMPENNAGE
Types
- Conventional / Standard
- Twin Vertical Stabilizers
- Triple Vertical Stabilizers
- V-Butterfly Tail
- T- Tail
Parts
- Vertical (Fin) and Horizontal Stabilizers
- Dorsal (Top) and Ventral (Bottom) Fins
- Ruders (yaw and p-factor) and Elevators (pitch)
- Right and Left Fin
LANDING GEAR
- Floaters / Hull
- Wheel (Dual, Tricycle and Multiple)
Types
- Nose Wheel (For Pusher Type)
- Main Landing Gear (fixed and retractable)
- Tail Wheel (For Tractor)
Specialized
- Rough Field
- Soft Field
CONTROL SURFACES
- Wing
- Flaps
- Ailerons
- Tail Unit
- Rudders (yaw and p factor)
- Elevators
Fairing – curving
Property of Materials
- Hardness (resist abrasion) vs
- Toughness (deformed w/o breaking)
- Elasticity (return orig shape) vs
- Plasticity (recover shape after deform)
- Malleability (hammer into shape w/o breaking) vs
- Ductility (bent w/o breaking)
- Strength (resist stress w/o deform) vs
- Stiffness (resist elastic deform)
- Fusibility (heat – liquid)
- Conductivity (carry heat and electricity)
- Contraction and Expansion
- Density (weight of unit volume) m/v
- Brittleness (deform w/o shattering)
Non-Metallic Materials
WOOD
Wood Structures
- Solid Wood (pie)
- Laminated Wood (2 – 3 pieces)
- Ply Wood (3 or more layers)
2 Basic Species Used in Aircraft Construction
- Hardwood (deciduous trees w/ broad leaves)
- Mahogany (heavier than spruce, aircraft skin)
- Birch (shock resistant, wing spars and propellers)
- Softwood (coniferous trees w/ needle like leaves)
- Sitka Spruce (common, free from defects)
- Douglas Fir (strength exceed, heavier than spruce, tends to split)
- Noble Fir (lighter, superior all properties except hardness and shock resistance. Heavy bending such as spars)
- Balsa (light wood, lack structural strength)
Wood: Defects
| Acceptable Defects | Non-Acceptable Defects | |
| Cross Grain | Spiral and Diagonal grain. Does not diverge from longitudinal axis | Grain exceeds longitudinal axis |
| Wavy, Curly, and Interlocked grain | Irregularities do not exceed spiral and diagonal grain | Within the limitations specified in the description of acceptable defects listed |
| Hard Knots | Sound, hard knots up to 3/8 inch diameter | Within the limitations specified in the description of acceptable defects listed |
| Pin knot Clusters | Small clusters small deviation of grain direction | Produce large effect on direction of the grain |
| Spike Knots | Reject wood | |
| Pitch Pockets | Center portion of the beam atleast 14 inches apart at the same growth ring don’t exceed 1-1/2 inches length and 1/8 inch depth | Within the limitations specified in the description of acceptable defects listed |
| Mineral Streaks | There is no decay | Decay wound |
| Checks, Shakes and Splits | Reject | |
| Compression Wood | Reject | |
| Compression Failures | Perform microscopic test or toughness test | |
| Decay | Red heart or purple heart |
Wood: Adhesives
- Casein Adhesive – powder from milk, deteriorates over the years
- Synthetic Resin Adhesives
- Resorcinol Glue – common, two part (resin and hardener)
- Phenol-formaldehyde – common aircraft grade plywood. Requires high curing temp and pressure, impractical in field
- Epoxy Resins – two part also. Requires less attention.
- Plastic Resin – urea-formaldehyde. Water, insect, and mold proof. Rapid deteriorates in hot, moist environment.
Wood: Inspection
- Moisture Metering
- Tapping
- Probing
- Prying (movement – separation)
- Smelling
- Visual Inspection
- External
- Internal
Wood: The bonding process
- Preparation
- Utilization
- Pot Life
- Open Assembly Time
- Closed Assembly Time
- Pressing
Clamping Pressure
- Performing
PLASTIC and RESINS
- Thermosetting resins – cannot softened and reshaped
- Themoplastic resins – can be soften by heat
- Cellulose Acetate – transparent and lightweight. Tendency to shrink and yellow. Acetone – softens (Aircraft windshield and side windows)
- Polyethylene – plastic bags, insulators, drums.
- Vinyl – seat covering, insulations, moldings, tubings. Flexible and resistant to chemical and moisture.
- Acrylic Resin – water clear plastic. Light transmission of 92%. (Aircraft windows and windshields)
- Polytetraflouroethylene (Teflon) – non-lubricated bearings, tubings, electrical devices and other applications.
AIRCRAFT FABRIC
- Process of covering aircraft open structures.
Fabric: Problem Areas
- Deterioration – exposure to UV radiation
- Tension – max airframe 350 degrees Fahrenheit
Aircraft Dope
- Adheres and protects fabric applied to other skin material
Aircraft Fabric and Synthetic
- STC (Supplemental Type Certificate) approved covering material
- Difference in fabric may be denier(linear density), tenacity (strength of fiber or yarn) , thread count, weight, shrink, tension and weave style
- Polyester Filaments
- Covering Procedures
- Installation
- Similar to natural fabric. Little slack as possible
Aircraft Fabric – Natural
- Used to recover and repair components of an aircraft.
Recovering Aircraft – same quality used by manufacturer
FAA – Fedaral Admissions and Regulations
Reinforcing tape – minimum 40 lbs resistance
Finishing tape – surface tape, should have same properties as fabric used in aircraft cover
Lacing Cord – minimum breaking strength of 40 lbs. Rib lace cord should have a micro-crystalline fungicidal wax, paraffin free wax, or beeswax coating to prevent wearing.
Machine thread – minimum 5 lbs breaking strength
Hand sewing thread – minimum 14 lbs break strength
Preparation of the structure for covering
- Battery box treatment
- Asphaltic, rubber based acid-proof coating application in the area of battery by box, brush (addtl. Protection from battery acid)
- Worn Holes
- Oversized screw holes or worn size 4 self tapping screw holes through ribs and other structures used to attach fabric may be redrilled a minimum 1-1/2 hole diameter distance from the original hole location with #44 drill bit.
Fairing Precaution – may cause a wrinkle to form in the fabric, at the edge of the lap joint. Trailing edges should be adequately secured to prevent movement and wrinkles.
Dope Protection – protective coating such as aluminum foil, cellulose tape, or dope proof paint to protect them against the action of the solvents in the dope.
Sealant Compound
- used to contain fuel, maintain cabin pressure, reduce fire hazards, exclude moisture, prevent corrosion, and fill gaps and smooth discontinuities on the aircraft exterior.
SEALING – is a process that confines liquids and gases within a given area or prevents them from entering area from which they must be excluded.
Categories of Compounds
- Silicone – white, red, grey. Used where heat resistance is required.
- Non-Silicone – any color. Heat resistance not required.
Specification and Classification
Class A – Brushcoat Sealant. (Thinned with solvent to provide viscosity suitable for
brushing).
Class B – Filleting Sealant. (Relatively heavy consistency with good thixotropic (low-
slump) properties).
Class C – Faying Surface Sealant. (Medium consistency for good spreadability).
Class D – Hole-Filling Sealant. (Similar to Class B but with very low slump).
Classes E and F – Sprayable sealant
Properties
Application Time (except class C)
Squeeze-out Life (class C) [ ex. C-20 minimum 20 hours]
Tack-free Time – hours after thawing
Cure Time
120 F or more – bubling may occur
Inside rib lacing [Rib – Fabric – Anti tear strip – reinforcement tape ] – surface tape