Sheetmetal & Non sheetmetalic structure

100問 • 1年前

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(1) When performing a ring (coin tap) test on composite structure, a change in sound may be due to damage or to transition to a different internal structure (2) The extent of separation damage in composite structures is most accurately measured by a ring (coin tap) test Regarding the above statements,

Only No.1 is true

Clad aluminum alloys are used in aircraft because they

Are less subject to corrosion than uncoated aluminum alloys

A well-designed rivet joint will subject the rivets to

Shear loads

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

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 thickness to the bend radius

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

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

Subtracting the setback from both legs

When necessary, what type of cutting fluid is usually acceptable for machining composite laminates?

Water only

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

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

A specially modified twist drill

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

Mild steel rivets are used for riveting

Steel parts

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

Number of locking collar grooves

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

Three times the diameter of the rivet shank

The coefficient of expansion of most plastic enclosure materials is

Greater than both steel and aluminum

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

90°

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

Rivet gauge, or transverse pitch is the distance between the

Centers of rivets in adjacent rows

Which statement is true regarding a cantilever wing?

No external bracing is needed

Fiberglass damage that extends completely through a laminated sandwich structure

May be repaired

Threaded rivets (Rivnuts) are commonly used to

Attach parts or components with screws to sheet metal

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

118°

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

A factor which determines the minimum space between rivets is the

Diameter of the rivets being used

What is the material layer used within the vacuum bag pressure system to absorb excess resin during curing called?

Bleeder

If a new safety belt is to be installed in an aircraft, the belt must conform to the strength requirements in which documents?

TSO C22

What is one of the determining factors which permit machine countersinking when flush riveting?

Thickness of the material is greater than the thickness of the rivet head

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

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

Low strength characteristics

Which rivet may be used as received without further treatment?

2117-T3

Cabin upholstery materials installed in current standard category airplanes must

Be at least flame resistant

A rivet set used to drive MS20470 rivets should

Have a slightly greater radius than the rivet head

The general rule for finding the proper rivet dimeter is

Three times the thickness of the thickest sheet

MS20426AD-6-5 indicates a countersunk rivet which has

An overall length of 5/16 inch

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

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

Requires the replacement of the damaged core and facing

When straightening members made of 2024-T4, you should

Straighten cold and reinforce

The classification for high tensile strength fiberglass used in aircraft structure is

S-glass

Repairs o 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

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

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

Sixteenths of an inch

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

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

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

Metal fasteners used with carbon/graphite composite structures

Must be constructed of material such as titanium or corrosion resistant steel

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

Ribbon direction

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

Longerons and stringers

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

140° and turn at a low speed

What is the minimum edge distance for aircraft rivets?

Two times the diameter of the rivet shank

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

Specific alloy used in the manufacture of the rivets

A piece of sheet metal is bent to a certain radius. The curvature of the bend is referred to as the

Bend radius

The installation of Cherrymax and Olympic-lok rivets is accomplished by utilizing

A pulling tool

Which is an identifying characteristic of acrylic plastics?

Zinc chloride will have no effect

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

Minimum radius of bend

What is the most common method of cementing transparent plastics?

Soak method

Which rivet is used for riveting nickel-steel alloys?

Monel

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

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

Carbide W-point

The purpose of a joggle is to

Allow clearance for a sheet an extrusion

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

To retard age hardening

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

60:40

Sandwich panels made of metal honeycomb construction ae used on modern aircraft because this type of construction

Has a high strength to weight ratio

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

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

Hundredths of an inch

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

165°

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

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

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)

What type loads cause the most rivet failures?

Shear

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

Repairable, using approved methods

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

Possibility of causing delamination

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

How does acoustic emission testing detect defects in composite materials?

By picking up the ‘noise’ of any deterioration that may be present

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

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

Covered with a thin coat of wax

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

Pot life

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

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

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

Alloy 2117 rivets are heat treated

By the manufacturer and do not require heat treatment before being driven

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

They can be installed with ordinary hand tools

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

Radius, thickness, and degree of bend

A potted compound repair on honeycomb can usually be made on damages less than

1 inch in diameter

Shallow scratches in sheet metal may be repaired by

Burnishing

The monocoque fuselage relies largely on the strength of

Skin or covering

You can distinguish between aluminum and aluminum alloy by

Testing with a 10 percent solution of caustic soda

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

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?

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 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

Fiberglass laminate damage out exceeding the first layer or play can be repaired by

filling with a putty consisting of a compatible resin and clean, short glass fibers.

Most rivets used in aircraft construction have

Dimples

Composite fabric material is considered to be the strongest in what direction?

Warp

The markings on the head of a Dzus fastener identify the

Body diameter, type of head, and length of the fastener

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

The orientation of the plies to the load direction

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

A DD rivet is heat treated before use to

Soften to facilitate riveting

When a piece of aluminum alloy is to be bent using 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

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

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

E-glass

100

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

airlaw

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