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33 Cards in this Set
- Front
- Back
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What are three forms of wood commonly used in aircraft construction? |
Solid, laminated, and plywood |
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What type of wood should be used when splicing or reinforcing plywood webs? |
The same type of wood as originally used |
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Name at least four different types of defects found in wood |
Knots, checks, splits, pitch pockets, cross grain, curly grain, decay, dry rot, etc. |
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Can a section of wood containing a hard knot be used? |
Yes, within specified limits |
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What type of glue may have been used in older wooden aircraft construction that requires careful inspection to detect deterioration? |
Caesein glue |
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What are the three types of glues used in modern aircraft construction and repair? |
Resorcinol glue, phenol-formaldehyde, and epoxy resin glue |
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Is compression wood acceptable for structural repairs? |
No |
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Why should the various pieces of wood being joined be kept in the same room for at least 24 hours prior to joining? |
To allow the moisture content to equalize, thereby minimizing dimensional changes to the wood |
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Why is it important to consider the open-assembly time when gluing wooden structures? |
If the max open-assembly time is exceeded, the joint may fail since the glue may begin setting up before the joint is assembled |
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Why is it important to apply the proper clamping pressure to a glue joint? |
Clamping forces air out of the joint, brings wood surfaces together evenly, and is, in part, responsible for the strength of the glue line |
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Describe some of the methods used to apply pressure to glue joints |
Clamps, nailing strips, power presses, Brad's, nails, and small screws |
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What minimum curing temp should be observed when joining wood with various adhesives? |
70 degrees Fahrenheit or as specified by glue manufacturer |
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When inspecting wood structures, why might it be important to consider stains and discolored areas? |
Stains and discoloration usually accompany decay or rot |
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Describe acceptable methods used to repair elongated bolt holes found in a wooden wing spar |
Remove the section containing the elongated holes and splice in a new section or replace the entire spar |
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What type of joint is used to splice a solid or rectangular wood spar? |
A scarf joint |
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In what areas are spices to a wood spar prohibited? |
Under an attachment fitting for the wing root, landing gear, engine mount, lift, or interplane strut |
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What is the maximum number of splices allowed for any single spar? |
2 |
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Describe the characteristics of a scarf joint |
The pieces to be joined are tapered or beveled on a slope of 1 to 10 or 1 to 12 |
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Why must the beveled cut be accurate on both pieces of wood being repaired with a scarf joint? |
The two pieces must match exactly to ensure a tight glue joint |
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What are two primary uses for plywood in aircraft construction? |
Gusset or reinforcing plates in aircraft skin |
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Provide examples of at least three types of plywood skin repairs |
Splayed patches, surface patches, plug patches, and scarfed patches |
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What type of patch should be used to repair small holes in thin plywood skin if the skin is less than 1/10 of an inch thick? |
A Splayed patch may be used if the hole can be cleared out to a diameter of less than 15 thicknesses of the skin |
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What should be done to prevent a plywood patch and pressure plate from sticking together if glue is extruded from the joint? |
Place a piece of wax paper or vinyl plastic between the patch and the pressure plate |
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Why are lightweight steel bushings sometimes used in wooden structures? |
Bushings prevent the wood from being crushed when bolts are tightened |
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What is the purpose of large surface area washers when used on wooden structures? |
Large washers provide additional bearing area for hardware to help prevent damage to the wood when the hardware is tightened |
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Name several facings and core materials used in bonded honeycomb structures intended for special applications |
Stainless steel, titanium, magnesium, plywood, glass, nylon, and cotton cloth |
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Describe the construction of a bonded honeycomb structure |
It is a laminated structure that has a solid facing bonded to either side of a core consisting of open, six-sided cells |
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What must be done with a damaged area in a bonded honeycomb structure prior to beginning repairs? |
The damaged area must be completely removed |
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A drill bit used for drilling composite should have an included angle of how many degrees? |
135° |
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What are the most common causes for delamination of a composite structure? |
Sonic vibration, expansion of internal moisture, liquid leakage, and a manufacturing error |
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What type of defect in, or damage to, a bonded honeycomb structure can be repaired to using the potted repair method? |
Filling a hole |
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Name some of the factors that cause crazing in transparent plastic windows and windshields |
Exposure to ultraviolet light, stress, solvents, and improper handling |
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How should a hole be drilled in plexiglass to avoid damage to the hole when the drill breaks through to the under side? |
Back up the plastic with a piece of wood and feed the drill slowly |
