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Flashcards in Wood Structures Deck (30):

What type of wood should be used when splicing or reinforcing plywood wood

The same type of plywood as originally used


Name at least four different types of defects found in wood

Knots, splits, decay, and dry rot


Can a section of wood containing a hard knot be used

Yes within specified limits


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

Casein glue


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

Resorcinol glue, phenol-formaldehyde glue, and epoxy resin


What is compression wood and why isn't it acceptable for aircraft structures

It has a high specific gravity and looks like it has an excessive growth of summerwood and is not acceptable because it is very detrimental to strength


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 contest to equalize which minimizes dimensional changes in the wood


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

If the open assembly time is exceeded the joint may fail since the glue may begin setting up before the joint is assembled


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

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


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

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


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

70 degrees Fahrenheit or as specified by the glue manufacture


When inspecting wood structures why might it be important to consider stains and dis colored areas

Means decay or rot


Describe the acceptance 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


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

Scarf joint


In what area are splices to a wood spar prohibited

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


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



Describe the characteristics of a scarf joint

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


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

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


What are the two primary uses for plywood in aircraft construction

Reinforcing plates and aircraft skin


Provide examples of at least three types of plywood skin repairs

Plug patches, surface patches, and scarfed patches


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

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


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

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


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


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

The damages area must be completely removed


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

135 degrees


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

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


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

Filling a hole


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

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


What are two forms of wood that are acceptable for the repair of wooden aircraft skin

Plywood and laminated woods


What are the three forms of woods commonly used in aircraft construction

Solid, laminated, plywood