Static Stability

One of the factors that limits the maximum aft position of the CG is:

• (a) minimum value of the stick force per ‘g.’

• (b) maximum longitudinal stability of the aeroplane

• (c) maximum elevator deflection

• (d) too small an effect of the controls of an aeroplane

In what way is the longitudinal stability affected by the degree of positive camber of an aerofoil?

• (a) Positive, because the CP moves aft as the AoA increases.

• (b) Negative, because the lift vector slopes forward as the AoA increases.

• (c) Positive, because the lift vector slopes backward as the AoA increases.

• (d) No effect, because the camber of the aerofoil produces a constant pitch-down moment coefficient independent of the AoA.

The aft movement of the CP during acceleration through the transonic flight regime will:

• (a) decrease the static lateral stability

• (b) increase the static longitudinal stability

• (c) decrease the longitudinal stability

• (d) increase the static lateral stability

How does the exterior appearance of an aeroplane change when it is trimmed for a speed increase?

• (a) The elevator is deflected further upward by a downward deflection of the trim tab.

• (b) The elevator is deflected further downward by a movable horizontal stabiliser.

• (c) The exterior appearance of the aeroplane will not change.

• (d) Elevator deflection is increased further downward by the upward deflection of the trim tab.

Aft movement of the CG will:

• (a) increase the elevator-up effectiveness

• (b) decrease the elevator-down effectiveness

• (c) not affect the elevator effectiveness

• (d) change the elevator effectiveness depending on the wing location

During the landing of a low-winged jet aeroplane, maximum elevator-up deflection is usually required when the flaps are (i) . . . . . . . . . and the CG is (ii) . . . . . .

• (a) (i) up; (ii) fully aft

• (b) (i) fully down; (ii) fully forward

• (b) (i) fully down; (ii) fully forward

• (c) (i) up; (ii) fully forward (d) (i) fully down; (ii) fully aft

The effect that a ventral fin has on the static stability of an aeroplane is longitudinal (i) . . . . . . ; lateral (ii) . . . . . . . . . ; directional (iii) . . . . . . . . . .

• (a) (i) none; (ii) negative; (iii) positive

• (b) (i) positive; (ii) negative; (iii) negative

• (c) (i) negative; (ii) positive; (iii) positive

• (d) (i) none; (ii) positive; (iii) negative

Sensitivity for a spiral dive will occur when:

• (a) the Dutch-roll tendency is too strongly suppressed by the yaw damper

• (b) the static directional stability is positive and the static lateral stability is relatively weak

• (c) the static directional stability is negative and the static lateral stability is positive

• (d) the static lateral and directional stability are both negative

The effect of heavy tropical rain on the aerodynamic characteristics of an aeroplane are to (i) . . . . . . . . .. Clmax and to (ii) . . . . . . . . .. Drag:

• (a) (i) decrease; (ii) increase

• (b) (i) decrease; (ii) decrease

• (c) (i) increase; (ii) increase

• (d) (i) increase; (ii) decrease

In straight and level flight the value of manoeuvre stability is 150 N/g. To achieve a load factor of 2.5 the increase of stick force necessary is:

• (a) 450 N

• (b) 150 N

• (c) 225 N

• (d) 375 N