Aircraft Coverings Review

Question 1

What aircraft covering material has to be tested for tensile strength?

Answer 1

Cotton.

Question 2

What does the quality, strength, and weight of the aircraft fabric depend on?

Answer 2

Vne speed and the wing loading.

Question 3

What are the Vne and wing loading of grade A cotton and intermediate cotton?

Answer 3

Grade A: Vne over 160mph and wing loading over 9Ibs/in.
Intermediate: Vne less than 160mph and wing loading less than 9Ibs/in.

Question 4

What is the minimum tensile strength of grade A cotton and intermediate cotton?

Answer 4

Grade A: 80Ibs/in. Intermediate: 65Ibs/in.

Question 5

Grade A cotton is airworthy down to what percentage and its new Ibs/in.?

Answer 5

Down to 70% of new, 56Ibs/in.

Question 6

Intermediate cotton is airworthy down to what percentage and new Ibs/in.?

Answer 6

Down to 70% of new, 46Ibs/in.

Question 7

What cloth is not affected by moisture, mildew, chemicals or acids?

Answer 7

Glass cloth.

Question 8

How is finishing tape used?

Answer 8

Placed over seams and ribs to cover the stitchings.

Question 9

How should finishing tape be cut for compound curves?

Answer 9

In the Bias direction.

Question 10

How is reinforcing tape used?

Answer 10

It is used between the fabric covering and rib stitching.

Question 11

What is the tensile strength of hand sewing thread?

Answer 11

14Ibs/in.

Question 12

What is the tensile strength of machine sewing thread?

Answer 12

5Ibs/in.

Question 13

What are the two types of grommets?

Answer 13

Plain and seaplane.

Question 14

What are the four ways of attaching fabric to ribs?

Answer 14

Screws with plastic washers, Martin clamps, pull rivets, and stitching.

Question 15

What are the advantages of nitrate dope over butyrate?

Answer 15

Lower cost, more weight reduction, and fire resistant.

Question 16

How do you determine what type of dope is on an aircraft?

Answer 16

While rubbing a section with lacquer thinner, nitrate will become softer immediately, butyrate takes longer.

Question 17

What is a retarder used for?

Answer 17

To slow down the evaporation of the solvents in the dope.

Question 18

What is the purpose of aluminum paste?

Answer 18

It shields the fabric from UV rays from the sun.

Question 19

What does fabric rejuvenator do?

Answer 19

Restores the resiliency of the old dope film.

Question 20

Why is acetone used on fabrics?

Answer 20

Removes grease from the fabric.

Question 21

What causes pinholes?

Answer 21

Oil or water in the air supply.

Question 22

What causes blushing?

Answer 22

High humidity, low temperatures, and drafts over freshly doped surfaces.

Question 23

What are the four machine sewn seams?

Answer 23

French fell.
Folded fell.
Modified fell.
Lap.

Question 24

Hand sewn seams must be locked with how many stitches and with what knot?

Answer 24

Every 10 stitches and tied off with a double half hitch.

Question 25

What are the two covering methods?

Answer 25

Envelope method and Blanket method.

Question 26

Anti-tear strips are used on wings with a Vne over what MPH?

Answer 26

250mph.

Question 27

What are the two field tests for fabrics?

Answer 27

Seyboth and Maule.

Question 28

With a L-shaped tear, where does the stitching start?

Answer 28

At the apex.

Question 29

How is polyester fabric shurnk?

Answer 29

With a calibrated iron.