AMT 1201S Metallic Structures

You can distinguish between aluminum and aluminum alloy by

testing with a 10 percent solution of caustic soda.

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.

(Refer to question # 8157 Figure 4.) The amount of material required to make the 90° bend is

0.3436 inch.

(Refer to question # 8111 Figure 1.) Which of the rivets shown will accurately fit the conical depression made by a 100° countersink?

1

Refer to question 8128 Figure 2.) Select the preferred drawing for proper countersinking.

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 & 2

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 & 4

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.

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.

What should be the included angle of a twist drill for hard metal?

118°

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.

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 & 3

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 and 3.

Which of the following are generally characteristic of carbon/graphite fiber composites? 1. Flexibility. 2. Stiffness. 3. High compressive strength. 4. Corrosive effect in contact with aluminum. 5. Ability to conduct electricity.

2, 3, and 4

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, 3, and 4.

Which rivet may be used as received without further treatment?

2117-T3.

(Refer to question # 8144 Figure 3.) Which is the grip length of the flush rivet?

3

(Refer to Figure 5.) What is the length of flat A?

3.7 inches.

(Refer to question #8176 Figure 7.) What is dimension F? Setback at D = .095 Setback at E = .068 Bend allowance at D = .150 Bend 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

The length of rivet to be chosen when making a structural repair that involves the joining of 0.032-inch and 0.064-inch aluminum sheet, drilled with a No. 30 drill, is

5/16 inch.

(Refer to question 8159 Figure 5.) What is the flat layout dimension?

6.8 inches

Which fiber to resin (percent) ratio for advanced composite wet lay-ups is generally considered the best for strength?

60:40

What should be the included angle of a twist drill for soft metals?

90°.

What type of bit should be used to drill holes in Plexiglas?

A specially modified twist drill.

A piece of flat stock that is to be bent to a closed angle of 15° must be bent through an angle of

165°.

The primary alloying agent of 2024-T3 is indicated by the number

2

Which rivet is used for riveting magnesium alloy structures?

5056 aluminum.

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

When making repairs to fiberglass, cleaning of the area to be repaired is essential for a good bond. The final cleaning should be made using

MEK (methyl ethyl ketone

Which rivets should be selected to join two sheets of .032-inch aluminum

MS20470AD-4-4

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.

One of the main advantages of Hi-Lok type fasteners over earlier generations is that

they can be installed with ordinary hand tools.

The general rule for finding the proper rivet diameter is

three times the thickness of the thickest sheet.

Most rivets used in aircraft construction have

dimples

How does acoustic emission testing detect defects in composite materials?

By picking up the 'noise' of any deterioration that may be present.

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 the rivet shank and remove the rivet with a punch

The classification for fiberglass reinforcement material that has high resistivity and is the most common is

E-glass

Select the alternative which best describes the function of the flute section of a twist drill.

Forms the cutting edges of the drill point.

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

Which part(s) of a semi-monocoque fuselage prevent(s) tension and compression from bending the fuselage?

Longerons and stringers.

Which rivet is used for riveting nickel-steel alloys?

Monel

Which statement is true regarding a cantilever wing?

No external bracing is needed

When riveting dissimilar metals together, what precautions must be taken to prevent an electrolytic action?

Place a protective separator between areas of potential electrical difference.

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.

What type loads cause the most rivet failures

Shear

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.

What is the minimum spacing for a single row of aircraft rivets?

Three times the diameter of the rivet shank.

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 is the minimum edge distance for aircraft rivets?

Two times the diameter of the rivet shank.

What reference tool is used to determine how the fiber is to be oriented for a particular ply of fabric

Warp clock (or compass

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.

Which is an identifying characteristic of acrylic plastics?

Zinc chloride will have no effect

Repairing advanced composites using materials and techniques traditionally used for fiberglass repairs is likely to result in

an unairworthy repair

Clad aluminum alloys are used in aircraft because they

are less subject to corrosion than uncoated aluminum alloys.

Threaded rivets (Rivnuts) are commonly used to

attach parts or components with screws to sheet metal.

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.

Rivet pitch is the distance between the

centers of adjacent rivets in the same row.

Rivet gauge, or transverse pitch is the distance between the

centers of rivets in adjacent rows.

If no scratches are visible after transparent plastic enclosure materials have been cleaned, their surfaces should be

covered with a thin coat of wax.

A factor which determines the minimum space between rivets is the

diameter of the rivets being used.

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.

The coefficient of expansion of most plastic enclosure materials is

greater than both steel and aluminum.

A rivet set used to drive MS20470 rivets should

have a slightly greater radius than the rivet head.

The Dzus turnlock fastener consists of a stud, grommet, and receptacle. The stud length is measured in

hundredths of an inch.

Unless otherwise specified, the radius of a bend is the

inside radius of the metal being formed.

The preferred way to make permanent repairs on composites is by

laminating on new repair plies.

Longitudinal (fore and aft) structural members of a semi-monocoque fuselage are called

longerons and stringers

Under certain conditions, type A rivets are not used because of their

low strength characteristics

When comparing the machining techniques for stainless steel sheet material to those for aluminum alloy sheet, it is normally considered good practice to drill the stainless steel at a

lower speed with more pressure applied to the drill.

Fiberglass damage that extends completely through a laminated sandwich structure

may be repaired

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.

A main difference between Lockbolt/Huckbolt tension and shear fasteners (other than their application) is in the

number of locking collar grooves.

The shop head of a rivet should be

one and one-half times the diameter of the rivet shank.

The length of a rivet to be used to join a sheet of .032-inch and .064-inch aluminum alloy should be equal to

one and one-half times the rivet diameter plus .096 inch.

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

Hole filling fasteners (for example, MS20470 rivets) should not be used in composite structures primarily because of the

possibility of causing delamination.

The length of time that a catalyzed resin will remain in a workable state is called the

pot life

The most important factors needed to make a flat pattern layout are

radius, thickness, and degree of bend

Aircraft structural units, such as spars, engine supports, etc., which have been built up from sheet metal, are normally

repairable, using approved methods

Fiberglass laminate damage that extends completely through one facing and into the core

requires the replacement of the damaged core and facing

The part of a replacement honeycomb core that must line up with the adjacent original is the

ribbon direction

When inspecting a composite panel using the ring test/tapping method, a dull thud may indicate

separation of the laminates

A well-designed rivet joint will subject the rivets to

shear loads.

The Dzus turnlock fastener consists of a stud, grommet, and receptacle. The stud diameter is measured in

sixteenths of an inch.

The monocoque fuselage relies largely on the strength of

skin or covering

If a streamline cover plate is to be hand formed using a form block, a piece of dead soft aluminum should first be placed over the hollow portion of the mold and securely fastened in place. The bumping operation should be

started by tapping the aluminum lightly around the edges and gradually working down into the center

Mild steel rivets are used for riveting

steel parts.

When straightening members made of 2024-T4, you should

straighten cold and reinforce

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.

On a sheet metal fitting layout with a single bend, allow for stretching by

subtracting the setback from both legs.

The strength and stiffness of a properly constructed composite buildup depends primarily on

the orientation of the plies to the load direction

When repairing a small hole on a metal stressed skin, the major consideration in the design of the patch should be

the shear strength of the riveted joint.

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.

Which of the following drill bit types work best when drilling an aramid fiber (Kevlar(c)) composite laminate?

Carbide W-Point.