Jeppesen Oral- Chapter 3 ( Wood, Composite, Transparent 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 or 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, decay, dry rot

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4
Q

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

A

Yes within 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, epoxy resin

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7
Q

Is compression acceptable for structural repair?

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 moisture content to equalize, minimizes dimensional changes to the wood

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9
Q

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

A

If maximum is exceeded, the joint may fail

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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 together evenly

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11
Q

Describe some of the methods used to apply pressure to glue joints

A

Clamps, nailing strips, power presses, brads, nail, 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 F or recommended by manufacturer

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13
Q

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

A

Usually accompany decay

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14
Q

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

A

Remove section containing the elognated hole and splice in a new section or replace entire spare

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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, inter-plane strut

17
Q

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

A

2

18
Q

Describe the characteristics of a scarf joint

A

Pieces are tapered or beveled on a slope of 1 to 10 or 1 to 12

19
Q

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

A

To ensure exact tight fit between the two

20
Q

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

A

Gusset (or reinforcing) plates and aircraft skin

21
Q

Provide examples of at least three types of plywood skin repairs

A

Splayed patches, surface patches, plug patches, 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, if the hole can be cleared out to a diameter of less than 15 thickness 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 of vinyl plastic between the patch and the pressure plate

24
Q

Why are light weight 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

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

27
Q

Describe the construction of a bonded honeycomb structure

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

Damage area must be complety removed

29
Q

A drill bit used for drilling composites should have an included angle of how many degrees?

A

135 degrees

30
Q

What are the most common causes for de-lamination of a composite structure?

A

Sonic vibration, expansion of internal moisture, liquid leakage

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 can cause crazing in transparent plastic window and windshields?

A

Exposure to UV light, 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 piece of wood and drill slowly