Wood Flashcards
How do you detect decay in a wood structure?
Stick a sharp pointed knife into the suspect area if it’s good it will come up as a long splinter , if it’s decayed it will come up as a chunk
Are mineral streaks in a piece of structural aircraft wood reason for rejecting wood ?
No, if there is no evidence of decay wood
How is compression wood identified
It has a high specific gravity , it appears to have an excessive growth of summer wood and it has a little contrast between spring wood and summer wood
Is a hard knot, 1/2. Inch in diameter allowed if it is in the web of a wing spar
No 3/8 inch diameter is its maximum allowable knot , and it must severe restrictions
Are pin knot clusters allowable in aircraft structural ?
Yes if they cause only a small effect on grain direction
What kind of glue is recommended for making repairs to a wood aircraft structure?
Synthetic resin and resorcinol glue
What reference material may be used for acceptable repairs to wood aircraft structure ?
Ac 43.13 1b chapter 1
How is a scarf spice on a wing reinforced
Solid spruce and birch plywood reinforcing plates are glued in each side of the spar and centered on each end of the scarf
What if the correct repair to a wooden aircraft wing spar if the wing attach bolt holes in the spar are elongated ?
Splice in a new section of the spar and drill new holes
What is the minimum taper to use when repairing a wood wing rio cap strip ?
12 times the thickness recommended and 10 times minimum
How is aircraft plywood prepared for making compound bend?
Soak the wood into hot water until its pliable
What if used to apply pressure to a glued joint when splicing a wood aircraft wing spar ?
Cabinetmakers parallel clamps
How much pressure must be applied to a glue joint in a price of soft wood to produce a strong joint?
125 to 150 pounds per square inch
What kind of repair is recommended for a hole in the plywood skin of an aircraft wing
A scarf patch
What is the recommended tapes for a splayed patch in a plywood aircraft skin ?
5 to 1
Which species of wood I’d consider to be the slandered when comparing other woods for use in aircraft structure ?
Sitka spruce
Why must abrupt changes in the cross sectional area of the wooden structure member be avoided ?
It concentrate stresses and can cause failures
What if the basic difference between laminated wood and plywood ?
Laminated wood all of the grain runs in the same direction while plywood , the grain in layers crosses the others in 90 or 45 degree angle
What effects does moisture have on wood aircraft structure ?
Moisture causes the wood to swell and crack while it drys out and it also allows fungus to develop in wood and causes it to decay
Which wood is more inclined to wrap flat grain or vertical grain
Flat grain
What is the recommended taper for a scarf patch in a plywood aircraft skin ?
12 to 1
Why should sandpaper never be used when preparing a scarf joint in a wing spar for splicing
The dust caused by sand paper will plug the pores of the wood so glue won’t get in to form a good bond
What is the largest hole in a plywood wing skin that can be repaired with a fabric patch ?
1inch in diameter
Why are light steel bushing often used in bolt holes in a wood wing spar ?
The bushing keeps the spar from being crushed when the nut in the attachment bolt is tightened
