Sheetmetal non metallic structures + Woods
(Refer to Figure 1.) Which of the rivets shown will accurately fit the conical depression made by a 100° countersink?
1
Which of the following are generally characteristic of aramid fiber (Kevlar) composites? 1. High tensile strength. 2. Flexibility. 3. Stiffness. 4. Corrosive effect in contact with aluminum. 5. Ability to conduct electricity.
1. High tensile strength. 2. Flexibility.
Proper pre-preg composite lay-up curing is generally accomplished by 1. applying external heat. 2. room temperature exposure. 3. adding a catalyst or curing agent to the resin. 4. applying pressure.
1. applying external HEAT. 4. applying PRESSURE.
A sheet metal repair is to be made using two pieces of 0.040-inch aluminum riveted together. All rivet holes are drilled for 3/32-inch rivets. The length of the rivets to be used will be
1/4 inch
The flat layout or blank length of a piece of metal from which a simple L-shaped bracket 3 inches by 1 inch is to be bent depends upon the radius of the desired bend. The bracket which will require the greatest amount of material is one which has a bend radius of
1/8 inch
The dimensions of an MS20430AD-4-8 rivet are
1/8 inch in diameter and 1/2 inch long 4/32 inch (1/8 inch) in diameter and 8/16 inch (1/2 inch) long.
When repairing puncture-type damage of a metal faced laminated honeycomb panel, the edges of the doubler should be tapered to
100 times the thickness of the metal.
A single-lap sheet splice is to be used to repair a section of damaged aluminum skin. If a double row of 1/8-inch rivets is used, the minimum allowable overlap will be
13/16 inch The minimum row distance is 2-1/2 D. (D = diameter) 4 D + 2-1/2 D = Total overlap. 6-1/2 D = 13/2 D Given the rivet diameter (D) specified in this question: 13/2(1/8") = 13/16 inches total overlap
When drilling stainless steel, the drill used should have an included angle of
140° and turn at a LOW speed.
Which of the following, when added to wet resins, provide strength for the repair of damaged fastener holes in composite panels? 1. Microballoons.2. Flox.3. Chopped fibers.
2. Flox.3. Chopped fibers.
How many of the following are benefits of using microballoons when making repairs to laminated honeycomb panels? 1. Greater concentrations of resin in edges and corners. 2. Improved strength to weight ratio. 3. Less density 4. Lower stress concentrations
2. IMPROVED strength to WEIGHT ratio. 3. LESS density 4. LOWER stress concentrations
Which of these methods may be used to INSPECT fiberglass/honeycomb structures for entrapped water? 1. Acoustic emission monitoring. 2. X-ray. 3. Backlighting.
2. X-ray. 3. Backlighting.
Which rivet may be used as received without further treatment?
2117-T3
(Refer to Figure 4.) The length of flat A is
3.750 inches.
(Refer to Figure 6.) What is dimension D?Setback = .252Bend allowance = .345
4.182
(Refer to Figure 7.) What is dimension F?Setback at D = .095Setback at E = .068Bend allowance at D = .150Bend allowance at E = .112
5.936
A sheet metal repair is to be made using two pieces of 0.0625-inch aluminum riveted together. All rivet holes are drilled for 1/8-inch rivets. The length of the rivets to be used will be
5/16 inch. Each of the two sheets of material to be riveted together has a thickness of 0.0625 inch.The total thickness of the material is 0.125 inch, and the 1/8-inch rivets should extend through the material for 1-1/2 diameters, which is 0.1875 inch.The total length of the rivet must be 0.3125 inch, which is 5/16 inch.
Which rivet is used for riveting MAGNESIUM ALLOY structures?
5056 aluminum
Which statement about wood DECAY is correct?
Decay IS NOT ACCEPTABLE in any form or amount.
On a semimonocoque fuselage, the skin is reinforced by LONGitudinal structural members called
LONGerons and stringers.
Under certain conditions, type A rivets are not used because of their
LOW STRENGTH characteristics.
The SHARPEST bend that can be placed in a piece of metal without critically weakening the part is called the
MINIMUM radius of bend
Which rivet is used for riveting NICKEL-steel alloys?
MONEL LIKE MONEY
Which rivets should be selected to join two sheets of .032-inch aluminum?
MS20470AD-4-4
When bending metal, the material on the outside of the curve stretches while the material on the inside of the curve compresses. That part of the material which is NOT AFFECTED BY EITHER stress is the
NEUTRAL line.
The cantilever wing uses
NO external bracing
The shop head of a rivet should be
ONE AND ONE-HALF times the diameter of the rivet SHANK
LAMINATED wood is sometimes used in the construction of highly stressed aircraft components. This wood can be identified by its
PARALLEL GRAIN construction.
The length of time that a catalyzed RESIN will remain in a workable state is called the
POT life.
What is one of the determining factors which permits machine countersinking when flush riveting
Thickness of the material is GREATER than the thickness of the rivet head.
What is the purpose of refrigerating 2017 and 2024 aluminum alloy rivets after heat treatment?
To RETARD age hardening
Which procedure is correct when using a reamer to finish a drilled hole to the correct size?
Turn the reamer ONLY in the cutting direction.
What reference tool is used to determine how the fiber is to be oriented for a particular ply of fabric?
WARP CLOCK
When necessary, what type of cutting fluid is usually acceptable for machining composite laminates?
Water ONLY
Which is considered GOOD practice concerning the installation of acrylic plastics?
When rivets are used, ADEQUATE spacer or other SATISFACTORY means to prevent excessive tightening of the frame to the plastic should be provided.
In cases of elongated boltholes in a wood SPAR or cracks in the vicinity of boltholes,
a new section of SPAR should be spliced in or the spar replaced entirely.
The installation of CHERRYMAX and Olympic-Lok rivets is accomplished by utilizing
a pulling tool
MS20426AD-6-5 indicates a countersunk rivet which has
an OVERALL length of 5/16 inch.
Compression failures in wood aircraft structures are characterized by buckling of the fibers that appear as streaks on the surface
at right angles to the grain.
The markings on the head of a Dzus FASTENER identify the
body diameter, type of head, and length of the FASTENER.
Shallow scratches in sheet metal may be repaired by
burnishing
Alloy 2117 rivets are heat treated
by the manufacturer and DO NOT require heat treatment before being driven.
Laminated wood spars may be substituted for solid rectangular wood spars
if the same QUALITY wood is used in both.
Aircraft structural units, such as spars, engine supports, etc., which have been built up from sheet metal, are normally
repairable, using APPROVED METHODS
Parts fabricated from Alclad 2024-T3 aluminum sheet stock must have all
scratches, kinks, tool marks, nicks, etc., must be held to a minimum.
When inspecting a composite panel using the ring test/tapping method, a dull thud may indicate
separation of the laminates.
The identifying marks on the heads of aluminum ALLOY rivets indicate the
specific ALLOY used in the manufacture of the rivets
When straightening members made of 2024-T4, you should
straighten cold and REINFORCE.
On a sheet metal fitting layout with a single bend, allow for stretching by
subtracting the setback from BOTH legs
You can distinguish between aluminum and aluminum alloy by
testing with a 10 percent solution of caustic SODA
When balsa wood is used to replace a damaged honeycomb core, the plug should be cut so that
the grain is PERPENDICULAR to the skin
The strength and stiffness of a properly constructed composite buildup depends primarily on
the orientation of the PLIES to the load direction
A category of PLASTIC material that is capable of softening or flowing when reheated is described as a
thermoPLASTIC
Pin knot clusters ARE permitted in wood aircraft structure provided
they DO produce a small effect on grain direction.
One of the main advantages of Hi-Lok type fasteners over earlier generations is that
they can be installed with ordinary hand tools
When installing transparent plastic enclosures which are retained by bolts extending through the plastic material and self-locking nuts, the nuts should be
tightened to a firm fit, then BACKED OFF one full turn.
When repairing large, flat surfaces with polyester resins, warping of the surface is likely to occur. One method of reducing the amount of warpage is to
use SHORT STRIPS of fiberglass in the bonded repair
Glue deterioration in wood aircraft structure is indicated
when a joint has separated and the glue surface shows only the imprint of the wood with NO WOOD FIBERS CLINGING to the glue.
Which of the following is one advantage of Hi-Lok fasteners?
Inability to be over-torqued.
Any wooden member that has been overstrESSed is subject to which type of failure?
ComprESSion
How many MS20470 AD-4-6 rivets will be required to attach a 10 x 5 inch plate, using a single row of rivets, minimum edge distance, and 4D spacing?
56 The plate is 10 inches long and 5 inches wide. The rivets have a diameter of 1/8 inch and there is an edge distance of two rivet diameters.This requires two rows of rivets 9-1/2 inches long and two rows that are 4-1/2 inches long. The total length of the rivet seams is 28 inches.If the rivets are spaced every 1/2 inch (4D spacing), 56 rivets are needed.
Which fiber to resin (percent) ratio for advanced composite wet lay-ups is generally considered the best for strength?
60:40
Where is information found concerning acceptable species substitutions for wood materials used in AIRCRAFT REPAIR?
AC 43.13-1B.
Which statement concerning wood decay is correct?
ANY form or amount of DECAY is not permitted. BAD
A piece of sheet metal is bent to a certain RADIUS. The curvature of the BEND is referred to as the
BEND RADIUS
What is the material layer used within the vacuum bag pressure system to ABSORB excess resin during curing called?
BLEEDER
Which of the following conditions will determine acceptance of wood with mineral streaks?
Careful INSPECTION fails to reveal any decay.
What is generally the best procedure to use when removing a solid shank rivet?
Drill to the base of the manufactured rivet head with a drill one size SMALLER THAN RIVET SHANK and remove the rivet with a punch.
What is indicated by a black 'smoky' residue streaming back from some of the rivets on an aircraft
FRETTING corrosion is occurring between the rivets and the skin
Select the alternative which best describes the function of the flute section of a twist drill.
Forms the CUTTING EDGES of the drill point.
The STRENGTH of a well-designed and properly prepared wood splice joint is provided by the
GLUE
The Dzus turnlock fastener consists of a stud, grommet, and receptacle. The stud length is measured in
HUNDREDTHS of an inch
The aluminum alloys used in aircraft construction are usually HARDENED by which method?
Heat treatment
Unless otherwise specified, the radius of a bend is the
INSIDE radius of the metal being formed.
Which statement is true regarding the inspection of a stressed skin metal wing assembly known to have been critically loaded?
If genuine rivet tipping has occurred, groups of CONSECUTIVE rivet heads will be tipped in the same direction.
What precaution, if any, should be taken to prevent corrosion inside a REPAIRED metal honeycomb structure?
Prime the REPAIR with a corrosion inhibitor and seal from the atmosphere.
A DD rivet is heat treated before use to
SOFTEN to facilitate riveting.
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.
What type loads cause the most rivet failures?
Shear.
What is the most common method of cementing transparent plastics?
Soak method IN CIDER
What is the purpose of a gusset or gusset plate used in the construction and repair of aircraft structures?
TO JOIN and reinforce intersecting structural members
If a new safety belt is to be installed in an aircraft, the belt must conform to the strength requirements in which document?
TSO C22.
What is the minimum edge distance for aircraft rivets?
TWO TIMES the diameter of the rivet SHANK.
What is the minimum edge distance allowed for aluminum alloy single lap sheet splices containing a single row of rivets as compared to a joint with multiple rows, all rivets being equal in diameter?
The minimum edge distance for the single row is EQUAL to that for the multiple row
When patching a plywood skin, abrupt changes in cross-sectional areas which will develop dangerous stress concentration should be avoided by using
circular or elliptical patches.
A faint line running across the grain of a wood spar generally indicates
compression failure.
If an aircraft's transparent plastic enclosures exhibit FINE CRACKS which may extend in a network over or under the surface or through the plastic, the plastic is said to be
crazing.
FiberGLASS laminate damage not exceeding the first layer or ply can be repaired by
filling with a putty consisting of a compatible resin and clean, short GLASS fibers.
If it is necessary to compute a bend allowance problem and bend allowance tables are not available, the neutral axis of the bend can be
found by ADDING approximately ONE-HALF of the stock thickness to the bend radius.
Sandwich panels made of metal honeycomb construction are used on modern aircraft because this type of construction
has a high strength to weight ratio
One of the best ways to assure that a properly prepared batch of matrix resin has been achieved is to
have mixed enough for a test SAMPLE
The preferred way to make permanent repairs on COMPOSITES is by
laminating on new repair PLIES
Metal fasteners used with CARBON/graphite composite structures
must be constructed of material such as titanium or corrosion resistant STEEL
A main difference between Lockbolt/Huckbolt tension and shear fasteners (other than their application) is in the
number of locking collar grooves
Superficial scars, scratches, surface abrasion, or rain erosion on fiberglass laminates can generally be repaired by applying
one or more coats of suitable resin (ROOM-TEMPERATURE catalyzed) to the surface
The SIGHT LINE on a sheet metal flat layout to be bent in a cornice or box brake is measured and marked
one radius from the bend tangent line that is placed UNDER THE BRAKE
When an MS20470D rivet is installed, its full shear STRENGTH is obtained
only after a period of age HARDENING.
Repairs or splices involving stringers on the lower surface of stressed skin metal wings are usually
permitted but are normally MORE CRITICAL in reference to strength in tension THAN similar repairs to the UPPER surface
The most important factors needed to make a flat pattern layout are
radius, thickness, and degree of BEND
The I-beam wooden spar is routed to
reduce WEIGHT
