Wood Structures Flashcards
How would you inspect wood for rot (decay)?
Inspect for a dark discoloration of the wood surface or gray stains along the grain.
What three forms of wood are used in aircraft?
Solid, Laminaded and Plywood.
What is a laminated wood assembly?
Two or more layers glued together with the grain of all layers approximately parallel.
How is aircraft plywood constructed?
Made of an odd number of thin plies, and the grains of each layer, placed 90° with the adjacente ply or plies.
What specie of wood is used as a standard for strenght?
Spruce
Are hard knots acceptable?
Yes, within specified limits.
Why is compression wood NOT acceptable?
It is very prejudicial to strength.
When are mineral streaks acceptable?
If the inspection fails to reveal any decay.
Why is it necessary to examine all strains and discoloration?
To determine if the stains are harmless, preliminar or advanced decay.
What types of glues are used in aircraft wood structure repair?
Casein, Epoxies, Phenol-formaldehyde, Resorcino/ Glue.
What type of glue may have been used in OLDER AIRCRAFT construction that requires careful inspection to detect deterioration?
Casein Glue.
What types of glues are used in MODERN AIRCRAFT wood structure repair?
Resorcinol glue, Phenol-formaldehyde glue and Epoxi resin glue.
What is the minimum °F for curing wood joints with resin glue?
70°F or as specified by the glue manufacturer.
Why it is important to consider the open-assembly time when gluing wooden structures?
Because if the maximum open-assembly time is exceeded the joint may fail since the glue my begin setting up before the joint is assembled.
Why it is important to apply the proper clamping pressure to a glue joint?
Clamping forces the air out, brings the wood surfaces together evenly and in part responsible for the strength of the glue line
Describe the acceptable methods used to repair enlongated bolt holes found in a wooden wing spar:
Remove the damaged section and splice in a new section or replace the entire spar.