Repair Of Wood Structures

Question 1

What kind of glue is recommended for making repairs to a wood aircraft structure?

Answer 1

Synthetic resin or resorcinol glue

Question 2

What reference material may be used for acceptable repairs to wood aircraft structure?

Answer 2

AC 43.13-1B, chapter 1

Question 3

How is a scarf splice on a wing spar reinforced?

Answer 3

Solid spruce or birch plywood reinforcing plates are glued to each side of the spar, centered at each end of the scarf

Question 4

What is the correct repair to a wooden aircraft wing spar if the wing-attach bolt holes in the spar are elongated?

Answer 4

Splice in a new section of the spar and drill new holes

Question 5

What is the minimum taper to use when repairing a wood wing rib cap strip?

Answer 5

12 times the thickness recommended, 10 times is minimum

Question 6

How is aircraft plywood prepared for making a compound bend?

Answer 6

Soak the wood in hot water until it is pliable

Question 7

What is used to apply pressure to a glued joint when splicing a wood aircraft wine spar?

Answer 7

Cabinetmakers parallel clamps

Question 8

How much pressure must be applied to a glue joint in a piece of softwood to produce a strong joint?

Answer 8

125 to 150 pounds per square inch

Question 9

What kind of repair is recommended for a hole in the plywood skin of an aircraft wing?

Answer 9

A scarf patch

Question 10

What is the recommended taper for a splayed patch in a plywood aircraft skin?

Answer 10

5 to 1

Question 11

What is the recommended taper for a scarf patch in a plywood aircraft skin?

Answer 11

12 to 1

Question 12

Why should sandpaper never be used when preparing a scarf joint in a wing spar for splicing?

Answer 12

The dust caused by sanding will plug the pores of the wood so the glue cannot get in to form a good bond

Question 13

What is the largest hole in a plywood wing skin that can be repaired with a fabric patch?

Answer 13

1 inch in diameter

Question 14

Where are light steel bushings often used in bolt holes in a wood wing spar?

Answer 14

The bushings keeps the spar from being crushed when the nut on the attachment bolt is tightened

Question 15

How long should a glue joint be kept under pressure when splicing a wood aircraft wing spar?

Answer 15

For at least 7 hours

Question 16

Which area of a wood wing spar must not contain any splice?

Answer 16

There must be no splice under wing attach fittings, landing gear fittings, engine mount fittings, or lift and interplane strut fittings

Question 17

What is done to a splice in a wood aircraft wing spar to strengthen the splice?

Answer 17

Reinforcing plates are glued to both sides of the splice