POF Q28 - Stability and Control Flashcards
Which of the following statements is correct?
Select one:
a.Static stability means that the aeroplane is also dynamically stable about the relevant axis.
b.A dynamically stable aeroplane would be almost impossible to fly manually.
c.Dynamic stability means that after being displaced from original equilibrium condition, the aeroplane will return to that condition without oscillation.
d.Dynamic stability is possible only when the aeroplane is statically stable about the relevant axis.
d.Dynamic stability is possible only when the aeroplane is statically stable about the relevant axis.
Positive static stability of an aeroplane means that following a disturbance from the equilibrium condition:
Select one:
a.the initial tendency is to diverge further from its equilibrium condition.
b.the tendency is to move with an oscillatory motion of decreasing amplitude.
c.the initial tendency is to return towards its equilibrium condition
d.the tendency is to move with an oscillatory motion of increasing amplitude.
c.the initial tendency is to return towards its equilibrium condition
If a body is dynamically unstable, any oscillations would be:
Select one:
a.neutral
b.contained
c.damped
d.divergent
d.divergent
An aeroplane that has positive static stability:
Select one:
a.is always dynamically stable.
b.can be dynamically stable, neutral or unstable.
c.is always dynamically unstable.
d.is never dynamically stable.
b.can be dynamically stable, neutral or unstable.
If an aircraft has negative dynamic and positive static stability, this will result in:
Select one:
a.undamped oscillations.
b.convergent oscillations.
c.divergent oscillations.
d.damped oscillations.
c.divergent oscillations.
An aeroplane that tends to return to its pre-disturbed equilibrium position after the disturbance has been removed is said to have:
Select one:
a.positive static stability.
b.neutral dynamic stability.
c.neutral static stability.
d.positive dynamic stability
a.positive static stability.
If an object is statically unstable, it will:
Select one:
a.oscillate.
b.return to the original position.
c.stop moving.
d.move in the direction of the displacement.
d.move in the direction of the displacement.
If the sum of all the moments in flight is not zero, the aeroplane will rotate about the:
Select one:
a.neutral point of the aeroplane.
b.longitudinal axis.
c.centre of gravity.
d.aerodynamic centre of the wing.
c.centre of gravity.
Static stability means that:
Select one:
a.the amplitude of the oscillatory motion of an aeroplane tends to increase over time.
b.following a disturbance from the equilibrium condition, a force and/or moment is generated that tends to increase the effects of that disturbance.
c.the amplitude of the oscillatory motion of an aeroplane tends to decrease over time.
d.following a disturbance from the equilibrium condition, a force and/or moment is generated that tends to counter the effects of that disturbance.
d.following a disturbance from the equilibrium condition, a force and/or moment is generated that tends to counter the effects of that disturbance.
An Aircraft that has Longitudinal stability has a
[ ] moment about the [ ] axis. Positive stability could cause a [ ] moment and if designated the symbol [ ].
[Pitching] [Lateral] [nose up] [M]
The point on an aerofoil where the size of the wing moment remains approximately constant at all angles of attack is known as the
a.Centre of Gravity.
b.Sum of reactive forces.
c.Centre of Pressure.
d.Aerodynamic Centre.
d.Aerodynamic Centre.
The aerodynamic centre for a positively cambered aerofoil at subsonic speed lies at a fixed point normally
a.between a range of 47% to 53% chord
b.between a range of 15% to 23% chord
c.between a range 27% to 32% chord
d.between a range of 23% to 27% of the chord
d.between a range of 23% to 27% of the chord
Consider a CL - Absolute Angle of Attack 𝛼a. For a positively cambered aerofoil, where does the curve cross the horizontal axis?
a.at 4º angle of attack.
b.To the left of the origin
c.The origin
d.to the right of the origin
c.The origin
