6.3.2

Question 1

What are the main lengthwise members in a wing called?

Answer 1

Spars

Question 2

What are wood spars normally made from?

Answer 2

Sitka spruce

Question 3

What is meant by a solid wood spar?

Answer 3

When the spar is made from one whole piece of wood

Question 4

What is meant by laminated wood spar?

Answer 4

When the spar is made from multiple pieces of wood glued together with the grain in the same direction

Question 5

What forces does a box spar take?

Answer 5

Torsional and bending

Question 6

What is the main cause of timber shrinkage?

Answer 6

Large cyclic changes of temperature and humidity

Question 7

What will long exposure to weather or strong sunlight do to wooden aircraft?

Answer 7

It will destroy the weather-proofing qualities of fabrics and surface finishes

Question 8

What happens when fabric covered ply structures are neglected?

Answer 8

Surface finish will crack allowing in moisture resulting in deterioration

Question 9

How should you store a wooden aircraft?

Answer 9

In a dry, well ventilated hangar with all inspection panels removed

Question 10

Before examining glued joints or carrying out repairs what must you ensure on a wooden aircraft?

Answer 10

That it is thoroughly dried out

Question 11

Upon opening an inspection panel what should you check?

Answer 11

For a smell of fungal growth or dampness

Question 12

Where does timber and glue deterioration often take place?

Answer 12

The inside of a structure

Question 13

Why is assessment of glued joints in wooden aircraft structures difficult?

Answer 13

There is no NDT for it and lack of accessibility

Question 14

Where access is required and no approved scheme exists who do you contact?

Answer 14

Aircraft manufacturer or a CAA approved organisation

Question 15

How are access holes created?

Answer 15

With a sharp trepanning tool and in a circular shape

Question 16

If a rectangle access hole is created, what must you ensure with the corners?

Answer 16

That they have the correct radii

Question 17

When checking a glue line what must be removed?

Answer 17

All protective coatings of paint by scraping

Question 18

When inspecting a glue line with a feeler gauge, what is the outcome if any penetration is possible?

Answer 18

The joint should be regarded a defective

Question 19

How is dry rot detected?

Answer 19

Small patches of crumbling wood

Question 20

What are the signs of water penetration?

Answer 20

Dark discolouration or grey streaks

Question 21

How is bruising and Cushing caused on wooden aircraft?

Answer 21

Over tightening of bolts

Question 22

How long is timber cut then stacked prior to shipment for?

Answer 22

60 days

Question 23

How long is timber usually seasoned in air-drying sheds for?

Answer 23

1-3 years

Question 24

What is the reason timber is seasoned?

Answer 24

It reduces moisture until it is the same moisture level as atmospheric moisture which allows ease of treatments

Question 25

Before taking timber for testing what should happen?

Answer 25

Approximately 6 inches should be cut from the end as it might be drier than the rest

Question 26

What are the two ways of testing for moisture content in timber?

Answer 26

Moisture meter and weighing before and after drying

Question 27

What is the general correct moisture content levels for timber?

Answer 27

15% with +/-2%

Question 28

If timber has a rate of growth of less than 6 rings per 25mm what should happen?

Answer 28

It should be rejected

Question 29

What are the two types of sawing?

Answer 29

Rift sawing and tangential sawing

Question 30

What is rift sawing?

Answer 30

When you cut timber along the radius of the rings

Question 31

What is tangential sawing?

Answer 31

When you cut timber at a tangent of the rings

Question 32

What sawing method is commonly known as flower-face?

Answer 32

Tangential sawing

Question 33

What is the worst defect for timber to have?

Answer 33

Dote disease

Question 34

What must you do if you find timber with dote disease?

Answer 34

Burn it

Question 35

What should you do if you find heart-shake or ring-shake in timber?

Answer 35

Cut it out

Question 36

When gluing wood together what is important?

Answer 36

Prevent end-grain gluing and apply pressure evenly over the surfaces

Question 37

What should you do before gluing plywood together?

Answer 37

Sand it to remove surface glazing and loose fibres

Question 38

What should happen to timber surfaces that are going to be glued?

Answer 38

They should be roughened to form a firm key for adhesives

Question 39

Why is moisture content important before glueing two pieces of wood together?

Answer 39

The pieces of wood should have the same moisture content to prevent swelling or shrinkage

Question 40

What should happen to temperature of the wood before gluing?

Answer 40

The wood should be left to settle at room temperature

Question 41

When gluing two pieces of timber together how should the glue be applied?

Answer 41

To both pieces with a glue spreader

Question 42

When using solvent adhesive why is it important to make sure it has all evaporated before using?

Answer 42

Bubbles may be created causing weakness

Question 43

What will happen if you’re applying too much heat to timber and freshly applied glue?

Answer 43

It could scorch the timber and cause the glue to bubble

Question 44

Where should tests of timber be carried out?

Answer 44

On off cuts

Question 45

If off cuts aren’t available to test on what should be used?

Answer 45

Representative test pieces

Question 46

When storing adhesives what should the temperature not exceed?

Answer 46

21C