Aircraft Fabric Covering
What is a tie-off knot?
A standard, modified seine knot used on all stitches expect the starting stitch.
What is the principal advantage of the envelope method for covering wings?
Almost all the seams are machine-sewed by the envelope supplier.
How would you determine the correct spacing for rip stitching if the original spacial wad unknown?
Consult the chart in AC43.13.1B
What two types of organic fibers are used for covering aircraft?
Cotton and linen
What types of inorganic fibers are used for covering aircraft?
Fiberglass and polyester .
Which of the several types of fabric is unaffected by moisture and mildew?
Fiberglass.
What is the function or purpose of reinforcing tape?
It is used between the fabric and the rib stitching to prevent the lacing cord from cutting through the fabric.
What is the purpose of the selvage edge on a roll of fabric?
It prevents the fabric from unraveling.
Fabric is considered unairworthy when it has deteriorated to what percentage of it's original Strength
Less than 70%.
What are the principle methods used to test the condition of the fabric
Maule tester and Seyboth tester.
Aircraft covering fabrics are made of materials from what two sources?
Organic and Inorganic
Where would you use surface tape?
Over rib stitching and sewed seams, over lapped edges, around corners, and along leading and trailing edges.
Name three common types of machine-sewed seams.
Plain overlap, Folded- fell, and French-fell.
What identification marking is found on the selvage edge, and in which direction is the warp applied?
The FAA-PMA stamp is found on the selvage edge and the warp is applied parallel to the line of flight.
How would you determine the strength requirements for fabric used to re-cover an aircraft?
The fabric must be of at least the quality and strength of the fabric used by the original manufacturer.
How are the fabric type and strength requirements determined for fabric-covered aircraft?
The original manufacturer determines the fabric type and the strength requirements are a function of the never-exceed speed and wing loading.
How should a structure that will be covered with dope fabric be prepared following inspection and prior covering?
Treat it with a protective coating of paint or varnish as appropriate
Where are anti-tear strips used?
Under wing rib stitching when the never-exceed speed is greater than 250 Mph.
How should the edges of drainage, inspection, and ventilation holes be reinforced?
With plastic, aluminum, or brass grommets .
What is meant by warp, weft, and bias
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