081.04 STABILITY

Question 1

Stability and manoeuvrability are (proportional/inversily proportional) to each other.

Answer 1

Stability and manoeuvrability are (inversily proportional) to each other.

Question 2

For an aeroplane to possess dynamic stability it needs static stability (and/or/and not) sufficient damping.

Answer 2

For an aeroplane to possess dynamic stability it needs static stability (and) sufficient damping.

Question 3

If the sum of the moments in flight is not zero, the aeroplane will rotate around the (neutral point/CG/aerodynamic centre of the wing/centre of pressure).

Answer 3

If the sum of the moments in flight is not zero, the aeroplane will rotate around the (CG).

Question 4

For an aeroplane in steady, straight and level flight, lowest value of lift occurs at CG (forward/aft) and (high/low) thrust.

Answer 4

For an aeroplane in steady, straight and level flight, lowest value of lift occurs at CG (aft) and (high) thrust.

Question 5

Phugoid oscillations are (short/long) preiod oscillations in which speed (remains approximately constant/varies significantly) around the (longitudinal/lateral/vertical) axis.

Answer 5

Phugoid oscillations are (long) preiod oscillations in which speed (varies significantly) around the (lateral) axis.

Question 6

For a properly loaded aircraft, put the following in right order, forward to aft:

• manouevre point
• CG
• neutral point

Answer 6

For a properly loaded aircraft, put the following in right order:

1. CG
2. neutral point
3. manoeuvre point

- CiNeMa -

Question 7

An aeroplane that exhibits insufficient stick force per g, can resolve this by installing a (bobweight/spring) which pulls the stick (forwards/backwards).

Answer 7

An aeroplane that exhibits insufficient stick force per g, can resolve this by installing a (bobweight) which pulls the stick (forwards).

Question 8

The part of an aeroplane that provides the greatest positive contribution to static longitudinal stability is the (engine/wing/horizontal tailplane/fuselage).

Answer 8

The part of an aeroplane that provides the greatest positive contribution to static longitudinal stability is the (horizontal tailplane).

Question 9

A sideslip angle is considered to be (positive/negative) during a sideslip to the left = nose pointing to the (right/left), (right/left) wing low and airflow coming from the (left/right).

Answer 9

A sideslip angle is considered to be (negative) during a sideslip to the left = nose pointing to the (right), (left) wing low and airflow coming from the (left).

Question 10

A sideslip angle is considered to be (positive/negative) during a sideslip to the right = nose pointing to the (right/left), (right/left) wing low and airflow coming from the (left/right).

Answer 10

A sideslip angle is considered to be (positive) during a sideslip to the right = nose pointing to the (left), (right) wing low and airflow coming from the (right).

Question 11

The contribution of swept back wings to static directional stability is (positive/negative/neglectible).

Answer 11

The contribution of swept back wings to static directional stability is (positive).

Question 12

The following have a positive effect on lateral stability:

• (high/low)-mounted wing
• (dihedral/anhedral)
• (swept-back/straight) wing
• (dorsal/ventral/dorsal and ventral)

Answer 12

The following have a positive effect on lateral stability:

• (high)-mounted wing
• (dihedral)
• (swept-back) wing
• (dorsal)

Question 13

A sideslip to the right is created by (left/right) wing down and (left/right) rudder.

Answer 13

A sideslip to the right (so nose to the left) is created by (right) wing down and (left) rudder.

Question 14

Flap extension (increases/decreases/doesn’t affect) lateral stability.

Answer 14

Flap extension (decreases) lateral stability.

Question 15

A yaw damper suppresses the tendency to (…).

Answer 15

A yaw damper suppresses the tendency to (Dutch roll).

Question 16

The following have a postitive effect on directional stability:

• (forward/aft) CG
• (swept-back/straight) wings
• (dorsal/ventral/dorsal and ventral)

Answer 16

The following have a postitive effect on directional stability:

• (forward) CG (longer arm)
• (swept-back) wings (more drag on wing into the wind)
• (dorsal and ventral)

Question 17

In a spiral dive, the aircraft (is/is not) in a stalled condition. It is caused by (strong/weak) directional and (strong/weak) lateral stability. It is a combined lateral and directional (periodic/aperiodic) motion.

Answer 17

In a spiral dive, the aircraft (is not) in a stalled condition. It is caused by (strong) directional and (weak) lateral stability. It is a combined lateral and directional (aperiodic) motion.

Question 18

A Dutch roll is caused by (strong/weak) directional and (strong/weak) lateral stability. It is a combined lateral and directional (periodic/aperiodic) motion.

Answer 18

A Dutch roll is caused by (weak) directional and (strong) lateral stability. It is a combined lateral and directional (periodic)​ motion.

Question 19

Consider an aeroplane with swept back wings. With increasing altitude and constant IAS the static lateral stability will (increase/decrease) and the dynamic lateral-directional stability will (increase/decrease).

Answer 19

Consider an aeroplane with swept back wings. With increasing altitude and constant IAS the static lateral stability will (increase) and the dynamic lateral-directional stability will (decrease).