Aeroplanlære - Kap 6 (Stability)

Question 1

What happens when stability increases?

Answer 1

Controllability decreases

Question 2

What happens when controllability increases?

Answer 2

Stability decreases

Question 3

What do we use our control inputs for?

Answer 3

We use it to overcome the aircraft’s stability

Question 4

What is a major difference between a jet and a airliner?

Answer 4

An airliner has more stability and a jet has less, since the jet needs more controllability

Question 5

What does the equilibrium of an aircraft mean?

Answer 5

The sum of all forces and moments are zero about the CG

Question 6

What is static stability?

Answer 6

The immediate response of an object when it is displaced from it’s equilibrium

Question 7

What is dynamic stability?

Answer 7

The subsequent response of an object over time

Question 8

What is the different categories of static stability?

Answer 8

Positive, negative and neutral static stability

Question 9

What is another word for negative stability?

Answer 9

Instability or divergence

Question 10

If an object has positively static stability, what does it do?

Answer 10

Move towards it’s equilibrium after being displaced (Ball inside a bowl)

Question 11

If an object has neutral static stability, what does it do?

Answer 11

Has no tendency to move initially (Ball on a flat surface)

Question 12

If an object has negatively static stability, what does it do?

Answer 12

Move away from it’s equilibrium after being displaced (Ball resting on top of an upside down bowl)

Question 13

How do we maintain equilibrium?

Answer 13

Continuous pilot input
Trim input

Question 14

If an aircraft is in trim what is it also?

Answer 14

In equilibrium

Question 15

How do you describe if an object is more stabile than another?

Answer 15

That it has a greater static stability

Question 16

What is the different categories of dynamic stability?

Answer 16

Positive, negative and neutral dynamic stability

Question 17

What does positive dynamic stability do, if its periodic?

Answer 17

Moves the object towards it’s equilibrium if the object is positively static stabile bouncing up and down

Question 18

Which two forms of positive dynamic stability is there?

Answer 18

Periodic or aperiodic

Question 19

What does positive dynamic stability do, if its aperiodic?

Answer 19

Moves the object towards it’s equilibrium if the object is positively static stabile without bouncing up and down

Question 20

What does neutral dynamic stability do?

Answer 20

Keep the same degree of oscillation until inputs are made from the pilot, if it has positively static stability

Keep the same degree of displacement input until inputs are made from the pilot, if it has neutral static stability

Question 21

What does negative dynamic stability do?

Answer 21

Keep making oscillations worse if the object has positively static stability

Move away from the objects equilibrium if the object has negative static stability

Question 22

Describe how the different stabilities work on each other

Answer 22

Question 23

How does longitudinal static stability work?

Answer 23

Increased or decreased lifton the tailplane pull tail up or down resetting nose position

Question 24

How is longitudinal static stability increased?

Answer 24

By increasing:
Tailplane area
The distance between tailplane and the CG

Moving the CG forward

Question 25

How is lateral static stability increased?

Answer 25

Question 26

What does dorsal fins do to stability?

Answer 26

Question 27

What does ventral fins do to stability?

Answer 27