11.9 Balancing & Rigging

Question 1

What is static balance ?

Answer 1

The tendency of an object to remain stationary when supported by it’s centre of gravity

Question 2

What are the two types of static balance ?

Answer 2

Under balance +
Overbalance -

Question 3

Why might a control surface need re balancing?

Answer 3

When repairs are performed, extra weight is added to the control surface.

Question 4

What is dynamic balancing?

Answer 4

When rotating forces are balanced so there is no vibration due to imbalance

Question 5

When a control surface needs re-balancing what should it be placed on ?

Answer 5

Supported from its hinges in a neutral position on a suitable stand for a jig, and must be able to move freely

Question 6

How may a control surface be checked for balance ?

Answer 6

Using a bubble protractor or by eyesight

Question 7

What are the most common methods of re-balancing?

Answer 7

-calculation method,
-scale method ,
-Balance beam method

Question 8

Why is the calculation method advantageous to all the other methods of re-balancing?

Answer 8

You do not have to take the control surfaces off the aircraft

Question 9

What must be known for the calculation method ?

Answer 9

The weight of the repair and the overall weight

Question 10

If the repair is not in tolerance after using the calculation method, what may be used ?

Answer 10

Weights may be used, however the correct ones will be specified

Question 11

What is the scale method ?

Answer 11

Requires the control surface to be supported on a jig in a neutral position on a stand, a scale is placed underneath to find the centre of gravity

Question 12

Where is the balance beam method mostly used ?

Answer 12

Cessna and piper aircraft

Question 13

What must be manufactured in order to use the balance beam method ?

Answer 13

A specialised tool

Question 14

What materials can be used to counterbalance a control surface ?

Answer 14

Lead or steel however on some large aircraft depleted uranium may be used

Question 15

What is rigging ?

Answer 15

The adjustment and travel of the movable flight control systems

Question 16

What must be done to the flight control surfaces during rigging?

Answer 16

Control surfaces must be attached to their according location

Question 17

What does rigging involve?

Answer 17

Setting cable tension, adjusting travel limits and setting travel stops

Question 18

What are rigging pins used for ?

Answer 18

Used to establish the correct position for components in a transmission

Question 19

If a control surface is rigged correctly, what should happen ?

Answer 19

Control surfaces should move through a prescribed arc and are synchronised with the flight deck controls

Question 20

What are the three general steps of checking range of movement ?

Answer 20

-lock flight deck controls, bell cranks and control surfaces in neutral
- adjust cable tension with flight controls remaining in neutral
-adjust the control stops to limit the control surface travel

Question 21

What tools can be used for checking movement of control surfaces ?

Answer 21

Protractors, rigging fixtures, contour templates and rulers

Question 22

What can be used when rigging pins are not provided ?

Answer 22

-alignment marks,
-templates,
-taking linear measurements

Question 23

What are adjustable and non adjustable stops?

Answer 23

Limits throw range or travel movement of control surfaces