SPINNING FINAL PAPER COMPLETE
QUESTIONS AND ANSWERS BUNDLED
STUDY RESOURCE
●● Dynamic stability
Answer: is the position with respect to time, or motion of an object after
a disturbance. Positive, neutral or negative.
●● How do static and dynamic stability relate?
Answer: If an object does not have positive static stability, it cannot have
positive dynamic stability.
●● Equilibrium
Answer: occurs when the sum of the forces and moments around the
center of gravity (CG) are equal to zero
●● Wing sweep helps or hurts longitudinal static stability?
Answer: When an F-14's wings are swept forward, they have a strong
longitudinally destabilizing effect. This is because the wing's AC is well
forward of the airplane's CG. This increases the F-14's maneuverability.
As sweep angle increases (i.e. the wings move aft), the wings' AC moves
aft, closer to the airplane's CG (Figure 1-9-11), making the airplane
more longitudinally stable. Sweeping an airplane's wings back is a
positive contributor to longitudinal static stability.
, ●● Fuselage effect on longitudinal stability?
Answer: The fuselage acts as an airfoil and thus produces lift. The
fuselage's AC is usually located ahead of the airplane's CG. If a
disturbance causes an increase in angle of attack, the fuselage will
produce greater lift that produces a destabilizing effect. The fuselage is a
negative contributor to longitudinal stability.
●● High vs low mounted wing on lateral static stability?
Answer: a high mounted wing is a positive contributor, and a low
mounted wing is a negative contributor to lateral static stability.
●● Different axis stability
Answer: Longitudinal stability is stability of the longitudinal axis around
the lateral axis (pitch). Later- al stability is stability of the lateral axis
around the longitudinal axis (roll). Directional stabili- ty is stability of
the longitudinal axis around the vertical axis (yaw).
●● Lateral stability effects; wings, fuselage, vertical tail, wing
placement
Answer: advancing wing on a straight winged airplane has a momentary
increase in airflow velocity as it moves forward. This increases parasite
drag on that wing and pulls it back to its equilibrium position. The swept
design of a wing will further increase directional stability. The
advancing wing not only experiences an increase in parasite drag, but
also an increase in induced drag due to the increased chordwise flow.
QUESTIONS AND ANSWERS BUNDLED
STUDY RESOURCE
●● Dynamic stability
Answer: is the position with respect to time, or motion of an object after
a disturbance. Positive, neutral or negative.
●● How do static and dynamic stability relate?
Answer: If an object does not have positive static stability, it cannot have
positive dynamic stability.
●● Equilibrium
Answer: occurs when the sum of the forces and moments around the
center of gravity (CG) are equal to zero
●● Wing sweep helps or hurts longitudinal static stability?
Answer: When an F-14's wings are swept forward, they have a strong
longitudinally destabilizing effect. This is because the wing's AC is well
forward of the airplane's CG. This increases the F-14's maneuverability.
As sweep angle increases (i.e. the wings move aft), the wings' AC moves
aft, closer to the airplane's CG (Figure 1-9-11), making the airplane
more longitudinally stable. Sweeping an airplane's wings back is a
positive contributor to longitudinal static stability.
, ●● Fuselage effect on longitudinal stability?
Answer: The fuselage acts as an airfoil and thus produces lift. The
fuselage's AC is usually located ahead of the airplane's CG. If a
disturbance causes an increase in angle of attack, the fuselage will
produce greater lift that produces a destabilizing effect. The fuselage is a
negative contributor to longitudinal stability.
●● High vs low mounted wing on lateral static stability?
Answer: a high mounted wing is a positive contributor, and a low
mounted wing is a negative contributor to lateral static stability.
●● Different axis stability
Answer: Longitudinal stability is stability of the longitudinal axis around
the lateral axis (pitch). Later- al stability is stability of the lateral axis
around the longitudinal axis (roll). Directional stabili- ty is stability of
the longitudinal axis around the vertical axis (yaw).
●● Lateral stability effects; wings, fuselage, vertical tail, wing
placement
Answer: advancing wing on a straight winged airplane has a momentary
increase in airflow velocity as it moves forward. This increases parasite
drag on that wing and pulls it back to its equilibrium position. The swept
design of a wing will further increase directional stability. The
advancing wing not only experiences an increase in parasite drag, but
also an increase in induced drag due to the increased chordwise flow.
