Sheet Metal and Non-Metallic Structures Flashcards
Rivet gauge, or transverse pitch is the distance between the…
centers of rivets in adjacent rows
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.
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 type of bit should be used to drill holes in Plexiglas?
A specially modified twist drill.
The part of a replacement honeycomb core that must line up with the adjacent original is the…?
ribbon direction.
A piece of sheet metal is bent to a certain radius. The curvature of the bend is referred to as the___________?
bend radius.
Parts fabricated from Alclad 2024-T3 aluminum sheet stock must have all…?
Scratches, kinks, tool marks, nicks, etc., must be held to a minimum.
Composite fabric material is considered to be the strongest in what direction?
Warp.
A well-designed rivet joint will subject the rivets to…?
shear loads.
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.
(Refer to Figure 1.) Which of the rivets shown will accurately fit the conical depression made by a 100° countersink?
130 degree
Which statement is true regarding a cantilever wing?
No external bracing is needed.
Which statement is true regarding a cantilever wing?
No external bracing is needed
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.
Which rivets should be selected to join two sheets of .032-inch aluminum?
MS20470AD-4-4.
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 is the minimum spacing for a single row of aircraft rivets?
Three times the diameter of the rivet shank.
The aluminum alloys used in aircraft construction are usually hardened by which method?
Heat treatment.
If no scratches are visible after transparent plastic enclosure materials have been cleaned, their surfaces should be…?
Covered with a thin coat of wax.
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.
Which of the following are generally characteristic of aramid fiber (Kevlar) composites?
- High tensile strength.
- Flexibility.
- Stiffness.
- Corrosive effect in contact with aluminum.
- Ability to conduct electricity.
High Tensile strength and Flexibility
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.
When necessary, what type of cutting fluid is usually acceptable for machining composite laminates?
Water only.
What is the minimum edge distance for aircraft rivets?
The times the diameter of the rivet shank.
Proper pre-preg composite lay-up curing is generally accomplished by
- applying external heat.
- room temperature exposure.
- adding a catalyst or curing agent to the resin.
- applying pressure.
applying external heat and applying pressure
Which is correct concerning the use of a file?
Apply pressure on the forward stroke, only, except when filling very soft metals such as lead or aluminum.
Rivet pitch is the distance between the…?
centers of adjacent rivets in the same row.
Which fiber to resin (percent) ratio for advanced composite wet lay-ups is generally considered the best for strength?
60:40
Hole filling fasteners (for example, MS20470 rivets) should not be used in composite structures primarily because of the…?
Possibility of causing delamination
Sandwich panels made of metal honeycomb construction are used on modern aircraft because this type of construction…?
has high strength to weight ratio.
MS20426AD-6-5 indicates a countersunk rivet which has
an overall length of 5/16 inch.
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.
When straightening members made of 2024-T4, you should
straighten cold and reinforce
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.
Unless otherwise specified, the radius of a bend is the…?
inside radius of the metal being formed.
Shallow scratches in sheet metal may be repaired by…?
burnishing.
(Refer to Figure 5.) What is the length of flat A?
3.7 inches.
(Refer to Figure 3.) Which is the grip length of the flush rivet?
C. (3) - The grip length of a rivet is the total thickness of the material held together by the rivet. In this question, the grip length is dimension 3.
Alloy 2117 rivets are heat treated
by the manufacture and do not require heat treatment before being driven.
A DD rivet is heat treated before use to…?
soften to facilitate riveting.
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.
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.
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.
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.
Which of the following need not be considered when determining minimum rivet spacing?
Rivet length.
When an MS20470D rivet is installed, its full shear strength is obtained
only after a period of age hardening.
The classification for fiberglass reinforcement material that has high resistivity and is the most common is…?
E-glass
Mild steel rivets are used for riveting ____ ____?
Steel Parts
The primary alloying agent of 2024-T3 is indicated by the number __?
2
The primary alloying agent in 2024-T3 aluminum alloy is copper, which is identified by the first digit 2.
The sharpest bend that can be placed in a piece of metal without critically weakening the part is called the ___________________________?
minimum radius of bend.
Joggles in removed rivet shanks would indicate partial…?
shear failure.
(1) When performing a ring (coin tap) test on composite structures, 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
Statement (1) is true. A change in the sound made by the coin being tapped on a piece of composite structure may be caused by damage or by a transition to a different type of internal structure.
Statement (2) is not true. The ring, or coin tap, test is a quick and unscientific type of test that gives an indication of possible damage but does not accurately measure the extent of separation.
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.
Aircraft structural units, such as spars, engine supports, etc., which have been built up from sheet metal, are normally…?
repairable, using approved methods.
The installation of Cherrymax and Olympic-Lok rivets is accomplished by utilizing…?
a pulling tool.
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.