Aircraft is said to be statically stable if _______

it has more thrust than drag

it has more lift than weight always

it has tendency to return to equilibrium state with the help of pilot�s input

it has initial tendency to come back to its original equilibrium condition after being disturbed

Correct Answer : it has initial tendency to come back to its original equilibrium condition after being disturbed

Explanation : An aircraft or an object is said to be statically stable if and only if it has initial tendency to return to its original equilibrium position after being disturbed. Lift is not always greater than the weight. At cruise it will be equal to weight of the aircraft.

Recently Updated in Aircraft Design Questions

Which of the following is not the type of aircraft dynamic mode?

Phugoid

Flap

Dutch roll

Lateral mode

Correct Answer : Option (B) : Flap

Explanation : Flap is a high lift device. Flap is used to increase lift produced by the wing. Flaps are used to increase camber and overall surface area of the wing. This results in increased lift. Dutch roll, phugoid, lateral mode etc. are typical aircraft dynamic modes.

Which of the following is an example of longitudinal mode?

Dutch

Lateral

Phugoid

Aileron

Correct Answer : Option (C) : Phugoid

Explanation : Phugoid mode is an example of longitudinal mode. Dutch and lateral mode are not example of longitudinal mode. Aileron is known as primary control surface. Aileron is used to control the aircraft rolling moment.

Find critical damping coefficient if damping ratio is 0.5 and damping coefficient is 1.1.

2.2

4.1

4.9

5.2

Correct Answer : Option (A) : 2.2

Explanation : Critical damping coefficient damping coefficient/ damping ratio 1.1/0.5 = 2.2.