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問題一覧
1
Where can you find information on acceptable substitutions when doing a wood repair?
manufacturer
2
what is used to seal end grain of wood
sealer*
3
When tap testing wood what sound would indicate damage such as delamination of the wood?
hollow sound
4
A moisture meter is used to determine if a mineral streak exists?
false
5
plastic resin?
1. urea-formaldehyde glue, 2. glue rapidly deteriorates in hot humid climate 3. should be considered obsolete for wood repairs
6
major factors that cause wood to become damaged?
1. moisture 2. temperature 3. sunlight
7
which of the following is not an example of aircraft wood?
plastic wood
8
What type of adhesive is used on aircraft due to it meeting the strength and durability requirements?
?
9
What is heartwood?
inner / non living part of tree
10
Cross grain (diagonal, wavy, curly, interlocked, spiral) are acceptable provided?
it does not exceed runout limits
11
What is the MAIN benefit of using a jig to create a wood structure?
ensures uniformity in size, shape and structure
12
is glue strength dependant on clamping pressure?
yes, True
13
“Hardwood” is strong in compression, tension and shear loads. True or False?
True
14
DO NOT sand wood when preparing to apply adhesives as wood dust enters the pores of the wood and will NOT bond proper
true
15
What are two general types of adhesives used on wood aircraft structure?
synthetic resins / casein
16
which type of tree grows fast and has a low density?
soft wood
17
early wood & late wood
early wood; light colour, early spring growth, less dense Late wood; darker colour, late summer growth, denser, stronger
18
what is the correct “Runnout limitations” for wood ? what permits a cross grain as acceptable?
1 inch high, 15 inch long
19
Where are spar repairs PERMITTED? Select all that apply.
compression struts, drag and anti drag wire fittings
20
surface patch Is performed on plywood skin. The patch used should be made out of what material?
ply wood
21
what is used to seal bolt holes before installing fastener ?
varnish
22
what should you do when applying adhesives?
1. ensure clean surface free of contaminants 2. apply even and smooth coat of adhesive 3. ensure correct wood orientation 4. observe glue life 5. CLAMPING
23
When doing any wood repair you always want to use material same as original or approved substitute?
True
24
what is another term for slope of the grain? what are acceptable limits to this? ** not sure if i have correct answers**
cut with wood grain & grain slope in same direction
25
what causes bond failure?
1. improper glueing 2. wrong glue type 3. glued components with prolonged moisture exposure
26
what are acceptable wood substitutions? which one is most used?
repair should be same as wood, Sitka spruce is standard for comparing “check AC manufacture” for substitutions
27
name and describe plywood repairs?
5 types of plywood patches 1. splayed patch 2. surface patch 3. plug patch 4. scarf patch 5. fabric patch “small holes”
28
Bond failure can be caused by improper gluing, wrong glue type and moisture exposure?
true
29
scarf patch
1. most difficult 2. must run in the same direction
30
resorcinol glue ?
1. meets strength and durability requirements 2. two part “resin and hardener” 3. ensure quality fit and bonding pressure
31
moisture meter
correct chart for wood type/ temp and humidity reading > 20% ideal for fungus growth reading 8-> 16% good reading 10>12% best reading
32
A fabric patch can NOT be used in the following locations?
1. less than 1 inch from the rib 2. frontal area of fuselage 3. leading edges
33
what is a shake?
longtitudinal cracks usually between two annual rings “runs parallel or follows the grain”
34
Which of the following is a form of decay?
1. rot 2. dote “fungus growth in wood” 3. red heart rot 4. purple heart
35
phenol-formaldehyde ?
1. used in manufacturing aircraft grade plywood 2. curing requires high temp & pressure 3. NOT ideal for A/C repairs
36
Which way should the face grain run when performing a plug patch?
same direction as skin grain
37
PLYWOOD consists of layers of wood bonded together with the grain in each layer running parallel or perpendicular?
perpendicular
38
What is the most common reason stress damage occurs?
over tightening of fasteners
39
when performing a probing inspection; if the wood feels firm and solid that indicates decay or dry rot ? true or false
false
40
The time of applying the glue to time part must be assembled best describes?
open assembly time
41
which of the following is the #1 major disadvantage of wood structure aircraft?
1. increase in labour for manufacturing 2. increased maintenance 3. moisture 4. lack of uniformity of wood (grain, type, moisture content) 5. not isotropic
42
The time the pressure needs to be applied to allow the adhesive (glue) to cure is called PRESSING TIME?
True
43
epoxy?
1. two part resin & hardener 2. mix according to manufactures spec 3. penetrates well into wood 4. joints weaken with high temp and humidity
44
how to store wooden aircraft?
store in well ventilated hangar, ensure drain holes and ventilation holes are not plugged
45
fabric patch?
less than 1 inch diameter uses fabric and dope to cover “can’t be done if within 1” of framing member or leading edge”
46
what wood is used as the reinforced wood?
sikka spruce
47
What defects are NOT permitted in aircraft wood? Select all that apply.
shakes, spilts, checks
48
Hard knots are permitted under what limitations?
1. “20 inches away from other damage “ 2. not on projecting I-beams 3. not greater than 3/8” diameter
49
what permits a cross grain as acceptable ?
not acceptable unless within limitations
50
what can cause compression wood failures?
wood being over stressed in compression, due to; 1. natural forces “wind” 2. rough or irregular ground 3. rough handling of logs or lumber
51
what should you NOT do when applying adhesives
?
52
Reaction wood?
formed when a leaning tree tries to return to normal position. forms differently for hardwood and soft wood
53
Wood is cut quarter sawn. This is accomplished by rotating the log 90 degrees after each cut?
true
54
It is important to remove all contaminates from the surface BEFORE applying any finish to wood?
true
55
surface patch
1. patch applied to the surface (along ribs and frames) 2. easiest
56
3 forms of aircraft wood?
?
57
what is a moisture meter used for? what do readings indicate ?
measure moisture in wood, readings indicate temperature and humidity
58
if dope is going to be applied on the surface of wood, a dope proof sealer must be used when sealing end grain?
True
59
why do exterior finishes require more protection than interior finishes?
requires more protection due to; 1. weather 2. abrasion 3. sunlight
60
factors that wood can be damaged by?
moisture, sunlight, temperature
61
A scarf patch is the easiest repair to do?
False
62
what is true about laminated wood?
grain direction runs parallel in each layer
63
what causes slitting or cracking in wood?
wood shrinking at different rates
64
When doing a scarf joint the scarf must be cut in the SAME direction of the wood grain slope?
True
65
When performing a splayed patch the patch wood grain should run perpendicular to the original skin grain?
False
66
The useable life of the glue (time mixed to time used) best describes?
pot life
67
what is a check?
longitudinal cracks extending across the annual rings “runs perpendicular to or cut through the grain”
68
advantages of wood structure on aircraft?
1. high strength to weight ratio 2. light weight 3. easy to manufacture 4. no specialized tools 5. ideal for small production
69
laminated wood
laminated wood, 2 or more layers of solid wood ply wood is ?
70
After removing the screws located in the doubler of a plug patch what must be done?
fill holes with approved adhesive
71
fungus causes decay in wood?
True
72
Examples of spar structures include: Solid, box, internally & externally routed, laminated, I beam
common spar types; 1. Solid 2. box 3. internally & externally routed 4. laminated 5. I-beam
73
what is a fabric patch
1. used for small holes less than 1” 2. fills holes prior to patching 3. uses fabric and dope to cover
74
during inspection, if decay is NOT found on a mineral streak is it permitted?
acceptable if no decay is found after inspection
75
what are ways wood can be bent?
boiling water, Steam, by hand if thin enough
76
what can cause finish failure?
1. moisture 2. wood splitting / abraision 3. sunlight
77
splayed patch
1. used for holes 2. flush 3. for thin plywood 1/8”
78
different methods for inspecting aircraft? ** not sure if correct answer**
1. microscopic examination 2. toughness test
79
glue time periods
1. pot life 2. open assembly time 3. closed assembly time 4. pressure time
80
what is sap wood?
outter / living part of the tree
81
pin knot clusters, what are permitted limitations ?
are acceptable but only if they produce a small effect on grain direction not acceptable if they produce a large affect
82
What inspection method is used to inspect the bond of joints?
prying
83
what causes decay in wood?
caused by fungus on open wood
84
plug patch
1. produces flush surface 2. requires doubler 3. must run in same direction
85
The time between applying the glue and applying pressure best describes?
closed assembly time
86
When inspecting a mineral streak “discoloured wood” you must ensure it is free from?
decay