Lift

Question 1

What is the lift formula and describe its components?

Answer 1

0.5R * V2SCl
R is air density
V is airflow velocity squared
S is wing plan area
Cl is coefficient of lift

Question 2

What is the coefficient of lift Cl?

Answer 2

Lifting ability of the wing, Depends on shape of wing and AoA

Question 3

Describe centre of pressure?

Answer 3

Single point on the wing chord line at a right angle to the relative airflow, through which the wings lif tis produce. Not a fixed point, depends on distribution of pressure along aerofoil. Higher AoA, closer to the leading edge

Question 4

Describe the lift-weight pitching moments?

Answer 4

If the lift and weight aren’t acting through the same point it will cause a pitching moment. Change during flight as C of G changes during flight

Question 5

Describe aspect ratio?

Answer 5

ratio of the wings span to it’s geometric chord.
High aspect ratio in high lift aircraft
Low aspect ratio in low lift aircraft but more capable of higher speeds

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Question 6

What is lift?

Answer 6

Lift is force experienced due to pressure differences above and below the aerofoil.

Question 7

During what phase is lift the greatest?

Answer 7

Takeoff
greatest difference in pressure due to 4 things.
1) Configuration (flap setting)
2)Speed of airflow over the wing
3)AoA optimised during takeoff
4)Air density

Question 8

What is direct lift control?

Answer 8

Elevator and stabilizer are aerofoils which can directly effect lift control. The position creates an upward or downward balancing force that controls the lift produced from the main aerofoils.