Structures Final

A well-designed rivet joint will subject the rivets to

shear loads

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

number of locking collar grooves.

Alloy 2117 rivets are heat treated

by the manufacturer and do not require heat treatment before being driven.

The general rule for finding the proper rivet diameter is

three times the thickness of the thickest sheet

The shop head of a rivet should be

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

One of the main advantages of HI-LOK type fasteners over earlier generations is that

they can be installed with ordinary hand tools.

Which of the following is one advantage of HI-LOK fasteners?

Inability to be over-torqued.

The markings on the head of a Dzus fastener identify the

body diameter, type of head, and length of the fastener.

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

hundredths of an inch.

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

sixteenths of an inch

Threaded rivets (Rivnuts) are commonly used to

attach parts or components with screws to sheet metal.

The installation of CherryMax and Olympic-Lok rivets is accomplished by utilizing

a pulling tool

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

Forms the cutting edges of the drill point.

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

Shallow scratches in sheet metal may be repaired by

burnishing

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

90°

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.

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

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.

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 is the minimum edge distance for aircraft rivets?

Two times the diameter of the rivet shank

When drilling stainless steel, the drill used should have an included angle of

140° and turn at a low speed

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

Three times the diameter of the rivet shank

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

1

Which is correct concerning the use of a file?

Apply pressure on the forward stroke, only, except when filing very soft metals such as lead or aluminum

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.

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

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

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.

When straightening members made of 2024-T4, the aviation mechanic should

straighten cold and reinforce.

Clad aluminum alloys are used in aircraft because they

have surface layers of pure aluminum or aluminum alloy bonded to the core material to inhibit corrosion.

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

repairable, using approved methods.

A factor which determines the minimum space between rivets is the

diameter of the rivets being used.

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

118°

Parts fabricated from Alclad 2024-T3 aluminum sheet stock must have all

scratches, kinks, tool marks, nicks, etc., must be held to a minimum.

Rivet gauge, or transverse pitch is the distance between the

centers of rivets in adjacent rows.

Rivet pitch is the distance between the

centers of adjacent rivets in the same row.

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

1

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.

The identifying marks on the heads of aluminum alloy rivets indicate the

specific alloy used in the manufacture of the rivets.

When an MS20470D rivet is installed, its full shear strength is obtained

only after a period of age hardening.

Which of the following need not be considered when determining minimum rivet spacing?

Rivet length

What is the purpose of refrigerating 2017 and 2024 aluminum alloy rivets after heat treatment?

To retard age hardening

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

low strength characteristics

A rivet set used to drive MS20470 rivets should

have a slightly greater radius than the rivet head

Heat-treated rivets in the D and DD series that are not driven within the prescribed time after heat treatment or removal from refrigeration

must be reheat treated before use.

The dimensions of an MS20430AD-4-8 rivet are

1/8 inch in diameter and 1/2 inch long.

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

2

Which part of 2017-T36 aluminum alloy indicates the temper designation?

T36

Which part of the 2017-T36 aluminum alloy designation indicates the primary alloying agent used in its manufacture?

2

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

Most rivets used in aircraft construction have

dimples

MS20426AD-6-5 indicates a countersunk rivet which has

an overall length of 5/16 inch

Which rivet may be used as received without further treatment?

2117-T3.

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

3

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

MS20470AD-4-4

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

Mild steel rivets are used for riveting

steel parts

A DD rivet is heat treated before use to

soften to facilitate riveting

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.

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

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.

Joggles in removed rivet shanks would indicate partial

shear failure.

What type loads cause the most rivet failures?

Shear

Which rivet is used for riveting magnesium alloy structures?

5056 aluminum.

Which rivet is used for riveting nickel-steel alloys?

Monel

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 Figure 4.) The length of flat A is

3.750 inches

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

0.3436 inch

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

3.7 inches

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

6.8 inches

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.

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

165°

When a piece of aluminum alloy is to be bent using a minimum radius for the type and thickness of material,

the layout should be made so that the bend will be 90° to the grain of the sheet.

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

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.

Unless otherwise specified, the radius of a bend is the

inside radius of the metal being formed.

The sharpest bend that can be placed in a piece of metal without critically weakening the part is called the

minimum radius of bend.

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

radius, thickness, and degree of bend.

The purpose of a joggle is to

allow clearance for a sheet or an extrusion.

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.

(Refer to Figure 6.) Determine the dimensions of A, B, and C in the flat layout.

Setback = .252

Bend allowance = .345

A = .748, B = 1.496, C = 1.248.

(Refer to Figure 6.) What is dimension D?

Setback = .252

Bend allowance = .345

4.182

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

(Refer to 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

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

subtracting the setback from both legs.

The aluminum alloys used in aircraft construction are usually hardened by which method?

Heat treatment

Which of the following statements is true regarding replacement rivets?

The new edge distance of larger replacement rivet must not be less than minimums

Which of the following are the desired effects of using Alodine(r) (also known as Bonderite(r)) on aluminum alloy?

A slightly rough surface and increased corrosion resistance

If masking tape is applied to an aircraft, such as for trim spraying, and is left on for several days and/or exposed to heat, it is likely that the tape will

cure to the finish and be very difficult to remove

What is used to slow the drying time of some finishes and to prevent blush?

Retarder

Which type of coating typically includes phosphoric acid as one of its components at the time of application?

Wash primer

Which properly applied finish topcoat is the most durable and chemical resistant?

Polyurethane

Aluminum pigment in dope is used primarily to

reflect ultraviolet from the fabric.

A correct use for acetone is to

remove grease from fabric.

When humidity is low, what is likely to occur if unhydrated wash primer is applied to unpainted aluminum and then, about 30 to 40 minutes later, a finish topcoat is applied?

Corrosion

Fungicidal dopes are used in aircraft finishing as the

first coat to prevent fabric rotting and are applied thin enough to saturate the fabric

Before applying a protective coating to any unpainted clean aluminum, the aviation mechanic should

avoid touching the surface with bare hands

When humidity is low, what is likely to occur if hydrated wash primer is applied to unpainted aluminum and then, 30 to 40 minutes later, a finish top coat is applied?

A glossy, blush-free finish.

What is the usual cause of runs and sags in aircraft finishes?

Too much material applied in one coat.