Sheet Metal & Non-Metallic Structures

Question 1

1. What is the grip length of a rivet?

Answer 1

Combined thickness of the materials to be joined

Question 2

2. Where are special rivets, such as Huck or Cherry Lock rivets used?

Answer 2

both sides of structure are impossible to acess or limited space for bucking bar

Question 3

3. What is bonded honeycomb construction?

Answer 3

Laminar structure , bonded on both sides of core consisting of open 6 sided cell with dissimilar materials, increases the strength, reducing weight

Question 4

4. What type of materials are used in honeycomb construction

Answer 4

Stainless steel, titanium, magnesium, plywood, resin impregnated paper, e glass, nylon

Question 5

5. Where are sandwich construction assemblies used?

Answer 5

Bulkheads, control surfaces, fuselage panels, wing panels, randomness, empennage skins

Question 6

6. What procedures should be used to prevent damage to the hole when drilling though plexiglass?

Answer 6

Backed with wood, drill slow, modified drill bit 60 degree tip angle

Question 7

7. What calculations must be made when bending sheet metal?

Answer 7

Setback & bend allowance

Question 8

8. What factors are used to determine setback?

Answer 8

Radius of the bend & thickness of material

Setback = Radius+Thickness

Question 9

9. When bending sheet metel, how should the grain be in relation to the bend?

Answer 9

Grain should be perpendicular to the bend

Question 10

10. What is a bend tangent line?

Answer 10

Line which metal starts to bend

Question 11

11. What is a joggle?

Answer 11

Offset near the edge of a sheet of metal to allow clearance for a sheet or clearance

Question 12

12. What are several methods used in forming sheet metal?

Answer 12

folding, bumping, crimping, shrinking, & stretching

Question 13

13. What kind of metal forming is done by bumping?

Answer 13

Compound curves

Question 14

14. What is crazing and how does it occur?

Answer 14

Hairline cracks in surface of plastic. Caused by heat damage and excessive stress

Question 15

15. Briefly describe the anodizing process and what purpose it serves?

Answer 15

Aluminum alloys placed in electrolyte bath
Creates thin film of hydroxide to form
Anodized coating provide resistance to corrosion & bond for paint

Question 16

16. What are the proper dimensions for the shop head of a rivet?

Answer 16

After bucking
1.5x diameter in width
.5x diameter in height

Question 17

17. When inspecting plexiglass, what should you look for?

Answer 17

Crazing & discoloration

Question 18

18. What causes honeycomb structure to delaminate?

Answer 18

Moisture

Question 19

19. What are the acceptable repair, methods for bonded honeycomb structure that has been damaged?

Answer 19

Potted repair

Laminated glass fabric cloth overlay

Question 20

20. What size drill should be used for the common shank rivet diameter of 3/32inch,4/32 inch, & 5/32

Answer 20

3/32 use #40
4/32 use #30
5/32 use #21

Question 21

21. What is used for hole filling in bonded honeycomb repair?

Answer 21

Potting compund

Question 22

22. What is a lightening hole?

Answer 22

Holes cut into metal to increase strength and reduce weight

Question 23

23. What special precautions should be observed when repairing a radome?

Answer 23

Must retain strength & electrical transparency

Question 24

24. What is a warp line?

Answer 24

Highlighted strand in fabric used for ply orientation

Question 25

25. What does “pot life” mean?

Answer 25

Length of time resin is workable after mixed

Question 26

26. What is a Barcol hardness tester?

Answer 26

Device that pushes into material to measure if its cured or not

Question 27

27. What is done to honeycomb before repairing?

Answer 27

Removed damaged area

Either replace with potting compound or install honeycomb replacement plug

Question 28

28. What is the difference between thermoplastics & thermosetting plastics?

Answer 28

Thermoplastics can be remelted

Thermosetting cannot