Wood Structures

Question 1

Glue joints are usually designed to take what kind of loads?

Answer 1

Shear loads

Question 2

When inspecting failed glue joints, fibers on wood mean the glue is or is not at fault?

Answer 2

Glue is Not at fault

Question 3

When inspecting failed glue joints, no fibers on wood but grain imprint present means glue is or is not at fault?

Answer 3

Glue is at fault

Question 4

Decay is or is not acceptable in any form or amount in wood?

Answer 4

Not acceptable

Question 5

When inspecting wood condition, you should inspect for _______ failures which appear as ______ across the grain

Answer 5

You should inspect for COMPRESSION failures, which appear as A FAINT LINE across the grain

Question 6

3 forms of wood?

Answer 6

SOLID
LAMINATED
PLYWOOD

Question 7

Laminated wood has _____ or more layers of wood with the grains running ____

Answer 7

TWO or more layers, grains running PARALLEL

Question 8

Plywood usually has an _____ number of plies with the grain of each ply at a _____ angle from the adjacent ply

Answer 8

ODD number, 90 DEGREE angle (or 45 degree)

Question 9

The most common wood species?

Answer 9

SITKA SPRUCE

Question 10

Where do we look for substitution wood species?

Answer 10

AC43.13-1B for substitution

Question 11

Defects in wood should have a grain deviation no more than ___” over ___”

Answer 11

1” over 15” MAX

Question 12

Mineral streaks are acceptable as long as there is ______

Answer 12

NO DECAY

Question 13

Pin knot clusters are acceptable as long as they produce only a _____ ____ on grain deviation

Answer 13

Small effect on grain deviation

Question 14

Compression failures are or are not acceptable? How do they show up to the grain?

Answer 14

NOT ACCEPTABLE / appear as faint lines at right angles to the grain

Question 15

W1 =
W2 =

W1 - W2
———— X 100 = percent of moisture content
W2

Answer 15

W1 = weight before drying

W2 = weight after drying

Question 16

Moisture content percentage range

Answer 16

10% - 12%

Question 17

When glueing wood, should you apply glue to 1 or both surfaces?

Answer 17

Both surfaces

Question 18

When applying pressure, use ____to____ psi on softwood

Answer 18

125-150 psi

Question 19

When applying pressure use _____to____ psi on hardwood

Answer 19

150 - 200 psi

Question 20

What type screws can be used for small joints (ribs) ?

Answer 20

Small brass screws

Question 21

You should use ___ on small joints

Answer 21

Gussets

Question 22

The strength of a wood joint is provided by

Answer 22

The glue

Question 23

In test samples, the fractured piece should show at least ___% of the wood fibers evenly distributed over the fracture?

Answer 23

75%

Question 24

Should you ever smooth softwood surfaces with sandpaper that are to be glued?

Answer 24

N E V E R

Question 25

What can you use during plywood skin repair? (Patches)

Answer 25

(Patch)
SURFACE
PLUG
SPLAYED
SCARF

Question 26

Avoid abrupt changes in cross sectional areas which will cause stress concentrations by using what kind of patches?

Answer 26

Circular or elliptical patches

Question 27

A surface patch should extend at least ____times the skin thickness beyond the edges of the opening

Answer 27

Twelve times

Question 28

What kind of plug patch can be used on plywood skins?

Answer 28

Round and Oval patches

Question 29

Plug patches should only be used for _____repair not for damage of supporting structure under the skin

Answer 29

SKIN repair

Question 30

Edges of the plug patch are cut at ___Angle to the skin

Answer 30

Right angle

Question 31

Round plug patch are limited to a __” cut out

Answer 31

SIX INCH

Question 32

Oval plug patch max dimension is ___” long and ____” wide

Answer 32

7” long and 5” wide

Question 33

A splayed patch will provide a ___ surface

Answer 33

Flush

Question 34

In a splayed patch, taper the edges to ____T

Answer 34

TAPER EDGES TO 5T

Question 35

A ____ Patch is preferred for most skin repairs

Answer 35

SCARF PATCH

Question 36

In a scarf patch, the slope is ___to___

Answer 36

12 to 1

Question 37

In spar repairs, small damage areas on a web can be repaired with ____or____ patches

Answer 37

EXTERNAL OR FLUSH PATCHES

Question 38

In spar repairs, extensive damage should be repaired with ____patch

Answer 38

SCARF patch

Question 39

In spar repairs, no more than ___splices should be made in any one spar

Answer 39

TWO splices

Question 40

_____ wood spars can be substituted for solid spars

Answer 40

LAMINATED

Question 41

Spars can be spliced at any point except under:

Answer 41

Wing attachment fittings
Landing gear fittings
Engine mount fittings
Lift and interplane strut fittings

Question 42

For elongated bolt holes in a spar or cracks near bolt holes, you must ______in a new spar section or _____the entire spar

Answer 42

Splice or replace

Question 43

In rib repairs, cap strips can be repaired using _____splice

Answer 43

SCARF SPLICE

Question 44

Trailing edge repairs can be made by _____the damaged area and ____a block of soft wood

Answer 44

Removing the damaged area and inserting a block of soft wood

Question 45

Compression members can be repaired by using acceptable methods shown in AC_____________

Answer 45

AC43.13 1B PG 1-19 PARAGRAPH 1-46B (1,2,3), FIG 1-12

Question 46

Most moisture is found at the ____ point

Answer 46

Lowest

Question 47

What kind of failure strips glue

Answer 47

Tension failure

Question 48

Which direction should the grain be when replacing honeycomb

Answer 48

Perpendicular to the grain

Question 49

Hard knots are acceptable at ____”

Answer 49

3/8”