T50(E)(N16)T
NOVEMBER 2012
NATIONAL CERTIFICATE
AIRCRAFT METALWORK THEORY N3
(11021113)
16 November (X-Paper)
09:00 – 12:00
Candidates will require pens, a pencil, ruler and drawing instruments.
Calculators may be used.
This question paper consists of 4 pages and a 2-page diagram sheet.
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T50(E)(N16)T
DEPARTMENT OF HIGHER EDUCATION AND TRAINING
REPUBLIC OF SOUTH AFRICA
NATIONAL CERTIFICATE
AIRCRAFT METALWORK THEORY N3
TIME: 3 HOURS
MARKS: 100
________________________________________________________________________
INSTRUCTIONS AND INFORMATION
1.
Answer ALL the questions.
2.
Read ALL the questions carefully.
3.
Number the answers correctly according to the numbering system used in this
question paper.
4.
Start each question on a NEW page.
5.
ALL drawings and sketches must be neat and in good proportion.
6.
Write neatly and legibly.
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T50(E)(N16)T
QUESTION 1: TOOLS
1.1
1.2
1.3
FIGURE 1, DIAGRAM SHEET 1 (attached) shows a 'slip roll former'.
Give a description of this metal-forming machine and name the parts A to D.
(6)
FIGURE 2, DIAGRAM SHEET 1 (attached) shows a tool type. Name the
parts A to F and also indicate the name of the tool.
(7)
Name the portable hardness tester and describe how it is used.
(2)
[15]
QUESTION 2: MATERIALS
2.1
Give FOUR reasons why metals are electroplated.
2.2
To facilitate easy handling of aluminium a specific designated number is
allocated to alloys. Describe the main alloying elements of the following:
2.2.1
2.2.2
2.2.3
(4)
1xxx
5xxx
7xxx
(6)
[10]
QUESTION 3: CORROSION
3.1
3.2
How can dissimilar metals be protected against corrosion when magnesium is
involved?
Explain the anodising process with the aid of a sketch.
(3)
(7)
[10]
QUESTION 4: FASTENERS
4.1
Explain the difference between a channel gang nut and an anchor nut.
(4)
4.2
Explain the difference between radius dimpling and coin dimpling with the aid
of neat sketches.
(6)
4.3
Sketch and describe the removal of solid shank rivets.
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[20]
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T50(E)(N16)T
QUESTION 5: REPAIRS
5.1
5.2
Explain, with the aid of neat sketches, how a damaged transition honey comb
structure can be repaired.
Make a neat, labelled sketch of a semi-monocoque fuselage construction.
(15)
(5)
[20]
QUESTION 6: DEVELOPMENT
FIGURE 3, DIAGRAM SHEET 2 (attached) shows a transitional sheet metal article
rectangular to square.
Copy this article in the ANSWER BOOK and then develop the article. Show the full
development and construction lines to scale 1:1.
[15]
QUESTION 7: GENERAL
Indicate whether the following statements are TRUE or FALSE. Choose the answer
and write only true or false next to the question number (7.1 – 7.10) in the ANSWER
BOOK.
7.1
Joggles are used to form odd-shaped parts or finishing touches for which
large machines are not suitable.
7.2
Ketts saws are used to cut irregular lines on the inside of a sheet without
cutting through the edges.
7.3
The purpose of a hardness tester is to determine the results of the heattreatment process.
7.4
The hole to be drilled for a taper-lock fastener must be drilled at 10 degrees
perpendicular to the material.
7.5
The method to repair a dented steel-tube longeron is called a welded patch
repair.
7.6
The minimum spacing for a single row of aircraft rivets is two times the length
of the rivet shank.
7.7
The most commonly used aluminium alloy sheets on aircraft are 7075-T6.
7.8
Most rivets used during aircraft construction are known by their raised dottype rivets.
7.9
Black-coloured Cleco fasteners are 4,0 mm (5/32') fasteners.
7.10
Rivet pitch is the distance between one row of rivets and the next row.
TOTAL:
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T50(E)(N16)T
DIAGRAM SHEET 1
FIGURE 1
FIGURE 2
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T50(E)(N16)T
DIAGRAM SHEET 2
FIGURE 3
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