ACRM (NONMETALLIC) Flashcards
Used for some aircraft wing spars and is made of one solid piece cut from a log.
WOOD
Made of two or three pieces of thin wood glued together with the grain running in the same direction.
LAMINATED WOOD
Consists of three or more layers of thin veneer glued together so the grain of each successive layer crosses the others at an angle of 45 degrees or 90 degrees.
PLYWOOD
Come from deciduous trees having broad leaves
HARDWOOD
Come from coniferous trees with needle-like or scale-like leaves.
SOFTWOOD
Most common wood used in aircraft structures. Reference wood for aircraft construction.
SITKA SPRUCE
Maximum deviation of GRAIN DEVIATION
1:15
Identifies a point where a branch grew from the tree trunk. It weakens a board and are not acceptable in wood for aircraft construction or repair.
KNOT
Hard knots up to ______ inch at their maximum dimension are acceptable in aircraft wood.
⅜
are acceptable if they do not cause excessive grain deviation.
SMALL PIN-KNOT CLUSTERS
Small openings within the annual rings of a tree can fill with resin and form ____
Weakens a piece of wood slightly and are acceptable only in the center portion of a beam.
PITCH POCKET
If a tree leans in its growth, its annual rings are not concentric. Cannot be used in aircraft construction or repair.
COMPRESSION WOOD
Occurs when a tree falls and must not be confused with compression wood.
COMPRESSION FAILURE
Crack that runs across the annual rings of a board and occurs during the seasoning process.
CHECKS
Crack or separation that occurs when two annual rings separate along their boundary.
SHAKES
Lengthwise separation of the wood caused by the wood fibers tearing apart.
SPLITS
Caused by fungi that grow in damp wood.
DECAY
Hard in their normal state, but become soft and pliable when heated. When softened, it can be molded and shaped, and retain their shape when cooled.
THERMOPLASTIC RESINS
Transparent and light weight. However, it has a tendency to shrink and turn yellow.
When acetone is applied, it shrinks.
CELLULOSE ACETATE
Stiffer than cellulose acetate, more transparent and colorless. It burns with a clear flame and produces a fairly pleasant odor. If acetone is applied, it leaves a white residue but remains hard.
ACRYLIC
Usually have little strength in themselves and are generally used to impregnate linen, paper, or glass cloth. For example, both fiberglass cloth and mat have a great deal of strength for their weight, but lacks rigidity.
THERMOSETTING RESIN
To convert fiberglass into a useful structural material, it is impregnated with ____________ and molded into a desired form.
POLYSTER RESIN
cure by chemical action and differ from materials that cure by evaporation of an oil or solvent.
POLYESTERs
added to polyester resin to thin it and make it more workable.
STYRENE MONOMER
Extend their working time (pot life)
INHIBITORS
To initiate curing process, to suppress inhibitors.
CATALYSTS
To shorten the curing process, helps the catalysts.
ACCELERATORS
Low percentage of shrinkage, high strength for its weight, and the ability to adhere to a wide variety of materials.
EPOXY RESIN
Added to the resin to increase its viscosity.
THIXOTROPIC AGENTS
Among the more familiar thixotropic agents used in aviation maintenance are
MICROBALLOONS
When layers of paper are impregnated with a thermosetting resin such as phenol-formaldehyde or urea-formaldehyde, they can be molded into either flat sheets or complex shapes.
REINFORCING MATERIALS
Enhances the strength and durability of thermosetting resin.
GLASS FIBER
Form of glass fiber designed for use in high-temperature applications. It can withstand temperatures approaching 3,000F.
CERAMIC FIBER
Most commonly used cloth reinforcing fabrics. Soft yellow organic fiber that is extremely light, strong, and tough.
KEVLAR
Produces a change in the fiber’s molecular structure that makes it extremely lightweight, strong, and tough.
GRAPHITE FIBERS
To increase the strength and rigidity of many nonmetallic structures. Some of the more common core materials include honeycomb, aluminum, wood, and metal faced honeycomb.
LAMINATED STRUCTURAL MATERIALS
The cellular core for laminated honeycomb material may be made of
RESIN-IMPREGNATED PAPER / GLASS CLOTH
Most wood cores consist of ________ _______ that has been cut across its grain and the end-grain slabs bonded between two face sheets of fiberglass or metal.
BALSA WOOD
Honeycomb materials used in fiberglass laminations, the type of core is referred to as
METAL FACED HONEYCOMB
Serve both to retain fluids in their operating systems and to exclude air and contaminants. However, with the increased use of high pressure fluid systems, packings and gaskets must also be able to perform under a wide range of operating pressures and temperatures.
SEALS OR PACKINGS
Effectively seal in both directions and are used to prevent both internal and external leakage.
O-RING PACKINGS
re used with o-rings to prevent the o-ring from being forced out, or extruded, they are made of teflon.
BACKUP RINGS
One-way seals that are installed with the open end of the “V” facing the pressure.
V-RING PACKINGS / CHEVRON
Used in brake assemblies and brake master cylinders.
U-RING PACKINGS
Absorb the shock loads associated with landing, some older aircraft utilize shock absorber cord.
SHOCK ABSORBER CORD
Used in fluid systems around the end caps of actuating cylinders, valves, and other units.
GASKETS
Commonly used for spark plug gaskets and some hydraulic fittings.
SOLID COPPER WASHER
Used in areas such as between an engine crankcase and accessories.
CORK GASKETS
Used anywhere a compressible gasket is required. Its flexibility allows it to compress easily to provide a tight seal. Stay away from gasoline, oil, or some hydraulic fluids.
RUBBER SHEETING
Clean and lubricate the exposed portions of piston shafts.
WIPERS
Certain areas of all aircraft are sealed to withstand pressurization, prevent fuel leakage or passage of fumes, or to prevent corrosion by sealing against the weather.
SEALING COMPOUNDS
Ready for application as packaged.
ONE-PART SEALNT
Compounds requiring separate packaging to prevent curing prior to application.
TWO-PART SEALANT
Used for fuel tank sealant, resists deterioration from jet fuel.
PRC SEALANT
