8.3 Theory Of Flight

Question 1

What are the 4 forces acting on an aircraft?

Answer 1

• thrust
• drag
• lift
• weight

Question 2

Where does the weight always act?

Answer 2

Towards the centre of the earth

Question 3

In theory, where does weight, lift, thrust and drag all act on an aircraft?

Answer 3

The centre of gravity

Question 4

For stable flight, where must the centre of lift be?

Answer 4

Aft of the centre of gravity

Question 5

Where must the centre of lift be for level flight?

Answer 5

In the same place as the centre of gravity

Question 6

For steady flight conditions, what must the moments equal?

Answer 6

The sum of the moments = 0

Question 7

What is the force required to produce a turn called and where does it act?

Answer 7

The centrifugal force - acting horizontally

Question 8

What is the load factor (g-load)?

Answer 8

The resultant force (lift in turn)
————————————-
Weight

Question 9

What is the symbol for load factor?

Answer 9

n

Question 10

What are the principle lift augmentation devices?

Answer 10

• flaps
• slats
• slots

Question 11

How is the reduction of airspeed compensated for?

Answer 11

• Increased angle of attack

- The lift coefficient is therefore increased

Question 12

What are the four types of flaps?

Answer 12

• plain flap
• fowler flap
• split flap
• slotted flap

Question 13

What type of flap is the most efficient?

Answer 13

The fowler flap

• extends rearward/downward increasing area
• increases camber
• provides up to 90% increase in CLmax

Question 14

What is the purpose of slats?

Answer 14

• Increase the camber of the wing by extending forward of the leading edge.
• Reduce the flow separation at high angles of attack at low speeds