6. Materials & hardware - Q&A
62 questions found
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The dimensions of an MS20430AD-4-8 rivets are
- 1/8 inch in diameter and 1/4 inch long.
- 4/16 inch in diameter and 8/32 inch long.
- 1/8 inch in diameter and 1/2 inch long.
Why? i know that the diameter must be in thirty-seconds inch division while length is expressed in sixteenths so 4/32 equals 1/8 and 8/16 equals 1/2.. is it wrong?
A non-electrolytic chemical treatment for aluminium alloys to increase corrosion resistance and paint bonding qualities is called
- alodizing.
- anodizing.
- dichromating.
Why not anodizing?
The steepest slope permitted on the scarf of a scarfed plywood repair is
- 1 in 20.
- 1 in 4.
- 1 in 12.
I don't understand what is a scarf of a scarfed plywood
MS20426AD-6-5 indicates a countersunk rivet which has
- a shank length of 5/16 inch (excluding head).
- an overall length of 5/16 inch.
- a shank length of 5/32 inch (excluding head).
plz teach me how ?
A plate 10 inches by 5 inches is to be riveted with 3 rows of rivets, with the normal 4D rivet spacing and 2 D edge distance. The rivets are AN460AD4-6. How many rivets are required?
- 60.
- 52.
- 56.
How?
What is an open assembly time?
- The time elapsing between the application of the adhesive and the assembly of the joint components.
- The time between the adhesive being applied to the joint surfaces and their assembly.
- The time elapsed from the adhesive being applied to the joint surfaces to them being clamped.
Are the first two answers not the same?
Which of these is a common cause of corrosion?
- Water in fuel.
- Spilled battery acid.
- Untreated metal.
surely they are all common causes of corrosion?
If aluminium alloy is not quenched within the minimum time allowed after heat treatment is it will be
- subject to corrosion.
- malleable.
- brittle.
this question makes me confused
if Al alloy not quenched are more prone to intergranular corrosion aren't they? Please give me explanation
Excessive stress on fluid or pneumatic metal tubing caused by expansion and contraction due to temperature changes can best be avoided by
- providing bends in the tubing.
- avoiding long straight sections of tubing between fixed parts of the structure of the aircraft.
- Both answers above are correct.
The answer should be 'providing bends in the tubing.
Ref.:- page 114 of AC65-9A.
Which of the following is the definition of cure time?
- The period after which the surface of the compound no longer exhibits adhesive properties.
- The time required for the mixed compound to reach an initial rubbery state.
- Both answers are correct.
I think the answer should be either A or B.
This is the ref.
http://www.toolingu.com/definition-670130-41274-cure-time.html.
http://www.wisegeek.com/what-is-curing-time.htm
Capped nuts are used so
- to prevent leaks from pipe ends.
- the part is not over torqued as the bolt touches the captive part first.
- to ensure that it is dry bolted.
for this question the answer is part not over torqued as bolt touches the captive part first..
meanwhile for this question, the answer is to stop leak:
Capped nuts are used
• prevent overtightening due to the threaded portion being restricted by the cap.
• to provide a dry torque joint.
• to stop leaks.
care to explain anyone?
Capped nuts are used
- prevent overtightening due to the threaded portion being restricted by the cap.
- to provide a dry torque joint.
- to stop leaks.
need expanation
Where the edge of a new fabric section will be located within 1 inch of a structural member to which the fabric is attached by rib lacing or other methods, the new fabric section should
- be extended 3 inches past the structural member.
- be extended to meet the structural member.
- be designated a major repair.
this is wrong answer should be "be extended 3 inch past the structure member"
When does an aircraft fabric covering repair become a major repair?
- When the repair extends over a wing rib.
- When the repair extends over three adjacent wing ribs.
- When the repair extends over two adjacent wing ribs.
the answer should be when the repair extends over two adjavent wing ribs..
Spilled mercury on aluminium
- increases susceptibility to hydrogen embrittlement
- may cause impaired corrosion resistance if left in prolonged contact.
- causes rapid and severe corrosion in prolonged contact.
Why not the third option is correct ???
Hydraulic pipes are made from
- 1100 or 2020 H14.
- annealed steel.
- 5056 or 7075.
why do we use annealed steel ...as far as i know annealed steel are soft...
Colour identification of an aluminium rivet is
- black.
- violet.
- green.
what is the reference for this answer
Worm drives operate in shafts which are
- 90 degrees to each other and in a differing plane.
- 90 degrees to each other and in the same plane.
- parallel to each other and in the same plane.
Difference between axis and plane of gears?
Intergrannular corrosion in structural aluminium alloy parts
- are not likely to occur in parts fabricated from heat-treated sheet aluminium.
- may be detected by the white, powdery deposit formed on the surface of the metal.
- cannot always be detected by surface indications.
Intergrannular corrosion cannot be observed by visual inspection isn't it? Intergrannular corrosion are microscopic corrosion due to improper heating?
Co-axial cables are used
- as they are able to handle high current.
- as the fields due to current flow in the inner and outer cancel each other out.
- as they are protected from electromagnetic interference.
isn't current flow in the inner and outer canceling each other out in co-axial cables?
Galvanic action caused by dissimilar metal contact may best be prevented by
- applying a non-porous dielectric material between the surfaces.
- special precautions are not required if they are properly bonded.
- priming both the surfaces with a light coat of zinc chromate primer.
non-porous dielectric material between the surfaces will prevent dissimilar metal contant.. isn't it?
Fibreglass laminate damage not exceeding the first layer or ply can be repaired by
- filling with putty consisting of compatible resin and clean, short glass fibres.
- sanding the damaged are until aerodynamically smooth.
- trimming the rough adges and sealing with paint.
maybe filling with putty consisting of compatible resin is the right answer. does sanding repair fibreglass laminate damage?
Which fibre to resin (%) ratio for advanced composite wet lay-ups is generally considered the best?
- 60:40.
- 50:50.
- 40:60.
Referring to Jeppesen Airframe book. It states that ratio is 60% fibre and 40% resin.. please explain
If the cross sectional area of a cable is increased, what will happen to the voltage drop?
- Decrease.
- Increase.
- Stay the same.
why does the voltage drop decreases? According to my understanding, V=IR. When cross sectional area increases, resistance will increase, hence increasing the voltage. Are voltage and voltage drop both different things?
What load are spring hooks subjected to?
- Bending.
- Tension.
- Compressive.
Can anyone explain to me why the answer is bending not the tension?