How do you define the lift coefficient?

Lift to drag

Thrust to weight

Wing lift to weight of aircraft

Ratio of aerodynamic lift to the dynamic lift

Correct Answer : Ratio of aerodynamic lift to the dynamic lift

Explanation : Lift coefficient is defined as aerodynamic lift divided by Dynamic lift. Dynamic lift is defined as product of dynamic pressure and reference area. Lift coefficient of airfoil and wing will be different.

Recently Updated in Aircraft Design Questions

Find the approximate value of wetted area Swet for given reference area of Sref=20 unit and parasite drag coefficient of 0.0028. Consider equivalent skin friction coefficient Cf as 0.003.

12 unit

18.67 unit

20 unit

65 unit

Correct Answer : Option (B) : 18.67 unit

Explaination : Wetted area Swet = Parasite drag coefficient*Sref/Cf
= 0.0028*20/0.003 = 18.67 unit.

Consider equivalent skin friction coefficient as 0.0025 and Swet/Sref = 0.6. Evaluate parasite drag.

02.34

1.23

0.0015

0.000025

Correct Answer : Option (C) : 0.0015

Explanation : Parasite drag = equivalent skin friction coefficient*(Swet/Sref)
= 0.0025*0.6 = 0.0015.

Determine the initial estimation of parasite drag coefficient if, equivalent skin friction coefficient is 0.004 and ratio of wetted area to the reference area is 0.8.

0.0032

0.04

1.2

4.2

Correct Answer : Option (A) : 0.0032

Explaination : Parasite drag coefficient = equivalent skin friction coefficient*area ratio
= 0.004*0.8 = 0.0032.