Aircraft Covering Flashcards
What determines the required quality and strength of fabric that is to be used for covering aircraft?
The required strength and quality of aircraft fabric is determined by the pounds per square foot of wing loading, and the never-exceed airspeed of the aircraft.
When are anti-tear strips’ recommended, and where are they used?
Anti-tear strips are used on aircraft with never-exceed speeds in excess of 250 mph, and they are installed over the ribs under the reinforcing tape. They are recommended for the complete upper surface of the wings, and on the bottom surface of that part of the wing that is in the slipstream.
What is the maximum permissible deterioration of aircraft fabric before it is considered unworthy?
Fabric covering is considered unworthy when it deteriorates more than 30 percent from its originally required tensile strength.
What should be the strength of the fabric used for re-covering an aircraft?
All fabric, surface tape, reinforcing tape, thread and lacing cord used to re-cover or repair aircraft cover should be of high grade aircraft textile material. The materials must be at least as good a quality and of equivalent strength as those originally used by the aircraft manufacturer.
What is the purpose, location, and the method of installing drain grommets in aircraft fabric?
Drain grommets are located on the underside of airfoils at the trailing edge as close to the rib as practical, and at the lowest point along the center of the underside of each fuselage bay. They allow the condensed moisture to leave the aircraft as well as furnish ventilation. Brass grommets should be mounted on fabric patches and then doped to the covering. Plastic grommets are doped directly to the covering. Both types are installed with the second coat of dope, and the drain holes opened by cutting out the fabric with a small knife.
What is the purpose of reinforcing tape?
Reinforcing tape is used over ribs between the fabric covering and the rib stitching to prevent the stitching cord from cutting through the fabric.
What type of fabric is not affected by moisture and mildew?
Fiberglass fabric is not affected by moisture, mildew, chemicals, or most acids.
What methods are used to check the strength of doped fabric?
Fabric punch testers will provide a general indication of the strength of the fabric, but it a punch tester indicates that the fabric strength is marginal, a laboratory test should be performed to determine the actual strength of the fabric.
. What type of machine-sewed seams are used in aircraft covering?
Plain overlap seams, folded-fell seams, and French-fell seams.
What should be done with structure that will come in contact with doped fabric?
Treat all parts of the structure that will come in contact with doped fabric with a protective coating such as aluminum foil, dope-proof paint, or cellulose tape.
If the original rib stitch spacing cannot be determined when re-covering an aircraft. What rib stitch spacing should be used?
Use the rib stitch spacing chart in Advisory Circular 43.13-1B.
What is the standard tie-off knot used during rib stitching?
A modified seine knot is used to tie off all stitches except the starting stitch.
What do you call the edge of cloth, tape, or webbing that has been woven to prevent raveling?
Selvage edge.
The types of fabric used for covering aircraft are organic and synthetic. Name two organic and two synthetic fibers.
The organic fibers are cotton and linen. The synthetic fibers include fiberglass and heat shrinkable synthetic fibers such as nylon, orlon, and dacron.
When covering aircraft, where is surface tape used?
Sewed seams, lapped edges, and rib stitching or screws must be covered with pinked-edge surface tape.
