Metallic structures Flashcards
What are the four common basic stresses on an aircraft?
They are tension, compression, shear, bearing.
What is the grip length of a rivet?
The grip length is the combined thickness of the materials to be joined by the rivet.
Where are special rivets, such as Huck or Cherry lock rivets used?
They are used in places where access to both sides of the riveted structure is impossible
What is bonded honeycomb (sandwich) construction?
It is a laminar construction consisting of a combination of alternating dissimilar materials, assembled and fixed in relation to each other so that the properties of each can be used to attain specific structural advantages for the whole assembly while reducing weight.
What type of materials are used in honeycomb construction?
Honeycomb construction may employ stainless steel, titanium, magnesium, plywood, resin impregnated paper, E-glass, nylon in various combinations.
Where are sandwich construction assemblies used?
They are used for such areas as bulkheads, control surfaces, fuselage panels, wing panels, radoms, empennage skins, or shear webs.
What calculations must be made when bending sheet metal?
Setback and bend allowance
What factors are used to determine setback?
The radius of the bend and the thickness of the material. Setback= Radius+ Thickness.
When bending sheet metal, how should the grain be in relation to the bend?
The grain should be perpendicular to the bend.
What is a bend tangent line?
The line at which the metal starts to bend.
What is a joggle?
A joggle is an offset near the edge of a piece of sheet metal to allow clearance for a sheet or extrusion.
What are several methods used in forming sheet metal?
Folding, bumping, crimping, shrinking, and stretching
What kind of metal forming is done by bumping?
Compound curves.
Briefly describe the anodizing process and what purpose it serves.
Aluminum alloys are placed in an electrolytic bath which causes a thin film of hydroxide to form on the surface of the aluminum.
What are the proper dimensions for the shop head of a rivet?
1.5 times the diameter in width and .5 times the diameter in height after bucking.
What size drill should be used for the common shank rivet diameters of 3/32 inch, 4/32 inch, and 5/32 inch?
For a 3/32 rivet, a number 40. For a 4/32 rivet, a number 30. For a 5/32 rivet, a number 21.
What is a lightening hole?
Lightening holes are cut into rib sections, fuselage frames, and other structural parts to decrease weight.
When cutting a piece of sheet metal at the edge, and you bend the corners in, what needs to be done?
You must drill a relief hole.
When Riveting, what are some safety considerations to be made?
Wear safety glasses, Do not point rivet gun, Wear gloves, Don’t hold down trigger.
What are the markings on rivet heads and what do they mean?
The markings on the rivet head tell you the type of material. AD is a dimple, A is Plain, D is raised point, DD is double dash.
What type of aircraft structure uses the aircraft skin to support the load?
Monocoque.
What type of shielding gases are used for GTA welding?
Helium and argon.
If you do a circle sheet metal patch, with 8 rivets, how many degrees apart should the rivets be?
360÷8=45 degrees apart.
How is the inner sleeve tube held in the structural tube until the gap is welded?
It is held in place with rosette welds.
Why doesn’t a TIG welder use flux?
It has a helium shielding gas
When opening an acetylene container how many turns is the valve turned?
1.5 times
