WOOD & FABRIC

how many teeth per inch are there on a aircraft hack saw ?. from 18 to 22 teeth per inch. from 18 to 24 teeth per inch.

Which direction is the right to shrinkage ?. the shrinkage is the greatest in the tangential direction. (across the fiber and parallel to the growth). across the growth and parallel to the fiber.

Lacing cord shall have a minimum breaking strength of ?. forty Ibs. in single and 80 Ibs in double. 40 Ibs. in single and 70 Ibs in double.

Fabric per inch is measured in what?. is measured in threads per inch. is measured in fiber per inch.

How do you weigh a small aircraft ?. the platform scales are used to weigh a small aircraft and are specially built with low beams to allow them to fit under a low wing. Low scales.

when you put new fabric on. What % strength can it be?. 70 %. 60%.

What is the cause of blushing?. rapid drying of dope causes blushing (when humidity is comparatively high) humidity should be 65%. slow drying of dope causes blushing.

What is the main ingredient of dope ?. cellulose base coating (nitrocellulose). natural latex, which is used to give gloss and elasticity to the surfaces.

How can thermositure plastic be reformed ?. by using heat. by using cold work.

Which is the correct scarf joint ?. a. b. c.

Should rib repair be attached to the spar?. the attachment should be by means of adhesive with cement coated, barbed or spiral nails driven through the vertical rib members on each face of th spar. No, the rib repair should not be attached to the spar, as doing so can cause structural imbalance and compromise the wing's integrity.

What imaginary vertical plane from which all horizontal measurements are taken for balance purposes are called?. Datum. Cg.

Which drill do you use to hold a drill bit with a square shaft?. Brace (by a bow type brace). electric drill.

What is the most commonly used type of plywood for aircraft structure ?. there are two mahooany and birch. pine or cedar.

What is the clamping pressure in ponds per square inch for soft wood ?. 125 to 150 pounds per inch. 150 to 175 pounds per inch.

Which type of glue is used in aircraft wood structure ?. Synthetic resin. Epoxy.

What is the distance in square inches, in a row of nails ?. 1 square inch. 2 square inch.

What is the slope or angle on a scarf joint ?. 1 in 15. 2 in 20.

When the punch test fails on fabric, what do you do next ?. replace the fabric (if punch test fails the fabric should be condemned). Make a patch.

How do you jack a small aircraft ?. Jack on the jack points (electronic load cells may be placed between the jacks and the jack points to weigh the aircraft). Jack on any structural point.

Where exceptionally good drainage and ventilation is desired, what is used or what is it called ?. grommets (marine or seaplane grommets). plastic common drainage.

What are the outside layers of plywood called?. faces and face and back. face 1 and face 2.

A fungicidal paste mixed with a thinned coat of dope, and applied on what coat?. on the first coat. oon the thirth coat.

What are the inner layers called ?. the core and cross bands. inner and main.

What do you call a nut where they are installed at various locations on the wing and fusealge for the attachment of inspection doors, fuel tank cap covers and other parts called ?. fiber insert nut plates. Iron insert nut plates.

What is the most common form of modified wood found in aircraft construction ?. Plywood. Wet wood.

If fabric loses it's strength what should be done ?. remove it and recover the aircraft. a new Part is necessary.

On larger member (spar repair for example) how would you apply pressure?. by screw clamps such as cabinet makers parallel clamps and c clamps. Speed tape.

to prevent ultraviolet rays., Aluminum powder is mixed with clear dope and sprayed on when?. after the first coat of clear dope and just before the pigmented coats. after the pigmented coats.

what do you call a Patch where it is cut in around and taped in the spar, and patched?. plug patch. weld patch.

Surface patch plywood skins that are damaged between or along framing members may be repaired by surface or overlay patches if they are ?. Rectangular or triangular patches only. Circular patches only.

When the original routing for the inner rib bracing is not known the tape will be routed?. diagonally alternating between the top and the bottom of each rib cap. Straight from the top and the bottom of each rib cap.

What is the % of dope and thinner ?. 50/50. 60/40. 40/60.

How do you install a glass fabric on all wing ribs and other structural, attachments through out the air frame ?. double the number of original lace. Triple the number of original lace.

What is the best wood for use in aircraft or classified in which group ?. spruce (silk spruce. balsa.

How do you mix Rejuvenator ?. it is essentially a mixture of potent solvents and plasticizers. slow.

If the fabric is good but the dope is cracked, what can be done ?. It may be treated with rejuvenator. t may be treated with epoxy.

What adhesive is commonly used in the manufacturing of aircraft plywood ?. Phenol formaldehyde. Epoxy.

Which dope is using antifungi ?. Clear Dope. covered dope.

How many hours does fabric need to dry when it is ttached to the structure?. allow the fabric to dry completely, at least 48 hfs. (when all of the water has evaporated). allow the fabric to dry completely, at least 12 hfs.

What are the 3 most important points of a auger bit ?. screw, flute and cutting angle. size.

If the spar is damaged and it's 7/8 of an inch thick how long should the repair be?. if you don't have the right ans multiply 0.875*12=10.5). 1 1/2 times spar.

how do you strengthen polyester fabric on the aircraft ?. By heat (polyester fabric obtains maximum tension on the airframe at 350 o fahrenheit). By cold In freezer.

When you don't have a datum, which point on the aircraft do you use as a point of reference (for the purpose of balance) ?. moment (second is centre of gravity). front spar.

Scarf patch, what is the slope or angle needed for this patch?. 1 to 12. 1 to 20.

What is the maximum diameter of a hole or puncture that you can repair on a A wood skin structure (no more than what) with a plug patch ?. 6 inch. 5 inch.

How many days are needed for a repair to cure when it has been glued and clamped together?. 1 to 2 days (14 hrs). 3 days.

How do you strengthen the fabric on an aircraft?. Using heat applied by a house iron 225 to 250. in a oven.

What do you do next after the punch test?. Pull test. Water test.

What are the most commonly used fabrics on aircraft?. Dacron And Nylon. Cotton.

On a wing spar that is damaged what should the slope on the scarf splice be ?. from 1.10 to 1.12 or 1.10 to 1.14. from 1.30 to 1.50 or 1.30 to 1.60.