Airframe Oral (Jeppesen) Wood, Composite, and Transparent Plastic Structures Flashcards

1
Q

What are the three forms of wood commonly used in aircraft construction?

A

Solid, laminated, and plywood.

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2
Q

What type of wood should be used when splicing reinforcing plywood webs?

A

The same type of plywood as originally used.

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3
Q

Name at least four different types of defects found in wood.

A

Knots, checks, splits, pitch pockets, cross grain, curly grain, decay, dry rot, etc.

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4
Q

Can a section of wood containing a hard knot be used?

A

Yes, within specified limits.

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5
Q

What type of glue may have been used in older wooden aircraft construction that requires careful inspection to detect deterioration?

A

Casein glue.

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6
Q

What are the three types of glues used in modern aircraft construction and repair?

A

Resorcinol glue, Phenol-formaldehyde glue, and epoxy resin glue.

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7
Q

Is compression wood acceptable for structural repairs?

A

No.

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8
Q

Why should the various pieces of wood being joined be kept in the same room for at least 24 hours prior to joining?

A

To allow the moisture content to equalize, thereby minimizing dimensional changes in the wood.

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9
Q

Why is it important to consider the open-assembly time when gluing wooden structures?

A

If the maximum 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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10
Q

Why is it important to apply the proper clamping pressure to a glue joint?

A

Clamping forces air out of the joint, brings the wood surfaces together evenly and is in part responsible for the strength of the glue line.

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11
Q

Describe some of the methods used to apply pressure to a glue joint?

A

Clamps, nailing strips, power presses, brads, nails, and small screws.

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12
Q

What minimum curing temperature should be observed when joining wood with various adhesives?

A

70 degrees Fahrenheit or as specified by the glue manufacturer.

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13
Q

When inspecting wood structures, why might it be important to consider stains and discolored areas?

A

Stains and discoloration usually accompany decay and/or rot.

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14
Q

Describe the acceptable methods used to repair elongated bolt holes found in a wooden wing spar.

A

Remove the section containing the elongated hole{s} and splice in a new section or replace the entire spar.

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15
Q

What type of joint is used to splice a solid or rectangular wood spar?

A

A scarf joint.

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16
Q

In what areas are splices to a wood spar prohibited?

A

Under an attachment fitting for the wing root, landing gear, engine-mount, lift, or inter-plane strut.

17
Q

What is the maximum number of splices allowed for any single spar?

A

Two

18
Q

Describe the characteristics of a scarf joint.

A

The pieces to be joined are tapered or beveled on a slope of 1 to 10 or to 12.

19
Q

Why must the beveled cut be accurate on both pieces of wood being repaired with a scarfed joint?

A

The two pieces must match exactly to ensure a tight glue joint.

20
Q

What are the two primary uses for plywood in aircraft construction?

A

Gusset {or reinforcing} plates and aircraft and aircraft skin.

21
Q

Provide examples of at least three types of plywood skin repairs.

A

Splayed patches, surface patches, plug patches, and scarfed patches.

22
Q

What type of patch should be used to repair small holes in thin plywood skin if the skin is less than 1 / 10th inch thick?

A

A splayed patch may be used if the hole can be cleared out to a diameter of less than 15 thicknesses of the skin.

23
Q

What should be done to prevent a plywood patch and the pressure plate from sticking together if glue is extruded from the joint?

A

Place a piece of waxed paper or vinyl plastic between the patch and the pressure plate.

24
Q

Why are lightweight steel bushings sometimes used in wooden structures?

A

Bushings prevent the wood from being crushed when bolts are tightened.

25
Q

What is the purpose of large surface area washers when used on wooden structures?

A

Large washers provide additional bearing area for hardware to help preclude damage to the wood when the hardware is tightened.

26
Q

Name several facings and core materials used in bonded honeycomb structures intended for special applications.

A

Stainless steel, titanium, magnesium, plywood, glass, nylon, and cotton cloth.

27
Q

Describe the construction of a bonded honeycomb structure.

A

It is a laminated structure that has a solid facing bonded to either side of a core consisting of open, six-sided cells.

28
Q

What must be done with a damaged area in a bonded honeycomb structure prior to beginning repairs?

A

The area must first be inspected to determine the damaged area prior to completely removing the damaged material.

29
Q

A drill bit used for drilling composites should operate at approximately what speed?

A

Use an air-driven tool capable of a free speed of up to 20,000 rpm.

30
Q

What are the most common causes for delamination of a composite structure?

A

Sonic vibration, expansion of internal moisture, liquid leakage, and a manufacturing error.

31
Q

What type of defect in, or damage to, a bonded honeycomb structure can be repaired using the potted repair method?

A

Filling a hole.

32
Q

Name some of the factors that cause crazing in transparent plastic windows and windshields?

A

Exposure to ultraviolet light, stress, solvents, and improper handling.

33
Q

How should a hole be drilled in Plexiglas to avoid damage to the hole when the drill breaks through to the underside?

A

Back up the plastic with a piece of wood and feed the drill slowly.