8 Quiz STABILITY

Why do stick forces per g decrease at high altitude?

• Because stability is increased.
• Because of the influence of the yaw damper
• Because the TAS decreases
• Because there is less aerodynamic damping

The effect a more aft position of the CG has on the aeroplane’s longitudinal static stability (i) and the required deflection of the pitch control (ii) is:

• (i) smaller; (ii) smaller
• (i) larger; (ii) smaller
• (i) larger; (ii) larger
• (i) smaller; (ii) larger

The lateral static stability of an airplane is increased by:

• Fuselage-mounted wings, dihedral, T-tail
• sweep back, under-wing-mounted engines, winglets
• high wing, sweep back, large and high vertical tail
• low wing, dihedral, elliptical wing planform

In trimmed level flight an acceleration of 10 kt has the effect on stick-force stability is:

• greater at high speeds
• greater at low airspeeds
• not affected by speed changes
• the same at all speeds

If the CG is on the forward limit and the trimmable horizontal stabiliser position is maximum nose-down then:

• rotation will require additional stick force
• rotation will be unaffected
• early rotation is necessary
• the take-off warning system will be activated

In addition to providing positive longitudinal stability, which of the following ensures longitudinal stability at high angles of attack?

• longitudinal dihedral
• a dorsal fin
• a symmetrical vertical stabiliser
• geometric dihedral

The relationship between lateral static stability and directional static stability is:

• dominant lateral static stability increases the tendency to spiral instability
• dominant directional static stability increases the tendency to Dutch roll
• dominant lateral static stability increases the tendency to Dutch roll
• dominant lateral static stability decreases the tendency to Dutch roll

The aerodynamic centre (AC) is the point at which:

• Cl is the same for all angles of attack
• all aerodynamic forces are the same for any angle of attack
• the lift for any angle of attack is the same
• the pitching moment is constant for all normal angles of attack

The position that the CG should be located is:

• between the aft limit and the neutral point
• a sufficient margin ahead of the neutral point
• aft of the neutral point
• at the neutral point

Which statement is correct?

• During both a phugoid and a short period oscillation altitude remains approximately constant.
• During both a phugoid and a short period oscillation altitude varies significantly.
• During a phugoid altitude remains approximately constant, but during a short period oscillation it varies significantly.
• During a phugoid altitude varies significantly, but during a short period oscillation it remains approximately constant.