NON METALLIC STRUCTURE

Which statement about wood decay is correct?. Decay that occurs before the wood is seasoned does not affect the strength of the finished piece. A limited amount of certain kinds of decay is acceptable in aircraft woods since decay affects the binding between the fibers and not the fibers themselves. Decay is not acceptable in any form or amount.

Laminated wood spars may be substituted for solid rectangular wood spars. only in certain instances where the primary load is shared by one or more other original structural member. if the same quality wood is used in both. only upon specific approval by the manufacturer or the FAA.

Fiberglass damage that extends completely through a laminated sandwich structure. may be repaired. must be filled with resin to eliminate dangerous stress concentrations. may be filled with putty which is compatible with resin.

Fiberglass laminate damage that extends completely through one facing and into the core. cannot be repaired. requires the replacement of the damaged core and facing. can be repaired by using a typical metal facing patch.

Composite fabric material is considered to be the strongest in what direction?. Fill. Warp. Bias.

When balsa wood is used to replace a damaged honeycomb core, the plug should be cut so that. the grain is parallel to the skin. it is about 1/8 inch undersize to allow sufficient bonding material to be applied. the grain is perpendicular to the skin.

In cases of elongated bolt holes in a wood spar or cracks in the vicinity of boltholes,. it is permissible to ream the hole, plug with hardwood, and redrill. the spar may be reinforced by using hardwood reinforcing plates. a new section of spar should be spliced in or the spar replaced entirely.

The I-beam wooden spar is routed to. increase strength. obtain uniform strength. reduce weight.

Finishing tape (surface tape) is used for what purpose?. To help prevent 'ripple formation' in. To provide additional wear resistance over the edges of fabric forming structures. To provide additional anti-tear resistance under reinforcement tape.

A faint line running across the grain of a wood spar generally indicates. compression failure. shear failure. decay.

If no scratches are visible after transparent plastic enclosure materials have been cleaned, their surfaces should be. polished with rubbing compound applied with a damp cloth. buffed with a clean, soft, dry cloth. covered with a thin coat of wax.

How many fabric thicknesses will be found in a French-fell seam?. Five. Three. Four.

Which parts of a semi-monocoque fuselage prevent tension and compression from bending the fuselage?. Ribs and formers. Longerons and stringers. Bulkheads and skin.

The best method of repair for a fabric-covered surface which has an L-shaped tear, each leg of which is approximately 14 inches long, Is to. re-cover the entire bay in which the tear is located. sew from the end of each leg to the center of the tear with a baseball stitch and then dope on a patch. sew with a baseball stitch from the center of the tear out toward the extremity of each leg and then dope on a patch.

A potted compound repair on honeycomb can usually be made on damages less than. 4 inches in diameter. 2 inches in diameter. 1 inch in diameter.

Proper prepreg composite lay-up curing is generally accomplished by. adding a catalyst or curing agent to the resin. applying external heat and pressure. room temperature exposure and applying pressure.

One method of inspecting a laminated fiberglass structure that has been subjected to damage is to. strip the damaged area of all paint and shine a strong light through the structure. use dye-penetrant inspection procedures, exposing the entire damaged area to the penetrant solution. use an eddy current probe on both sides of the damaged area.

The preferred way to make permanent repairs on composites is by. bonding on metal or cured composite patches. riveting on metal or cured composite patches. laminating on new repair plies.

The coefficient of expansion of most plastic enclosure materials is. greater than both steel and aluminum. greater than steel but less than aluminum. less than either steel or aluminum.

How does acoustic emission testing detect defects in composite materials?. By picking up the 'noise' of any deterioration that may be present. By analyzing ultrasonic signals transmitted into the parts being inspected. By creating sonogram pictures of the areas being inspected.