Aero 317 - Aircraft Dynamic Stability Modes

Question 1

Three oscillatory modes (complex Eigenvalues)

Answer 1

1. Short Period
2. Phugoid
3. Dutch Roll

Question 2

Two non-oscillatory modes (real Eigenvalues)

Answer 2

1. Subsidence Roll
2. Spiral

Question 3

Short Period

Answer 3

Oscillation primarily in pitch rate. High frequency, variable damping.

Question 4

Phugoid

Answer 4

Oscillation in pitch and longitudinal speeds. Low frequency and damping.

Question 5

Dutch Roll

Answer 5

Oscillation in sideslip, roll and yaw rates. Similar frequency to short period, variable damping.

Question 6

Roll Subsidence

Answer 6

Damping of roll motion, stable and highly damped.

Question 7

Spiral

Answer 7

Slow developing motion in sideslip, roll and yaw. Typically slightly unstable. Causes loss of altitude and increase in airspeed.